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Sample records for rapid colorimetric method

  1. Rapid determination of capsaicinoids by colorimetric method

    OpenAIRE

    Ryu, Wang-Kyun; Kim, Hee-Woong; Kim, Geun-Dong; Rhee, Hae-Ik

    2016-01-01

    Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid–liquid extraction and liquid–liquid extraction in test tubes ...

  2. Rapid determination of capsaicinoids by colorimetric method.

    Science.gov (United States)

    Ryu, Wang-Kyun; Kim, Hee-Woong; Kim, Geun-Dong; Rhee, Hae-Ik

    2017-10-01

    Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid-liquid extraction and liquid-liquid extraction in test tubes followed by a colorimetric analysis on the capsaicinoids by a selective chromogenic reaction with Gibbs reagent (2,6-dichloroquinone-4-chloroimide). In the comparison of the capsaicinoid content by the colorimetric method and HPLC using acetone extracts of fresh pepper and dry red pepper as samples, R2 was 0.9973 and 0.9816, respectively, which shows a high linear correlation. In addition, a minimum of 1 μg/mL capsaicinoids can be detected and it was therefore determined that the method can efficiently analyze a great quantity of samples in a short time. Copyright © 2016. Published by Elsevier B.V.

  3. Rapid determination of capsaicinoids by colorimetric method

    Directory of Open Access Journals (Sweden)

    Wang-Kyun Ryu

    2017-10-01

    Full Text Available Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC, but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid–liquid extraction and liquid–liquid extraction in test tubes followed by a colorimetric analysis on the capsaicinoids by a selective chromogenic reaction with Gibbs reagent (2,6-dichloroquinone-4-chloroimide. In the comparison of the capsaicinoid content by the colorimetric method and HPLC using acetone extracts of fresh pepper and dry red pepper as samples, R2 was 0.9973 and 0.9816, respectively, which shows a high linear correlation. In addition, a minimum of 1 μg/mL capsaicinoids can be detected and it was therefore determined that the method can efficiently analyze a great quantity of samples in a short time.

  4. A rapid and specific colorimetric method for free tryptophan quantification.

    Science.gov (United States)

    Wu, Yinan; Wang, Tianmin; Zhang, Chong; Xing, Xin-Hui

    2018-01-01

    Tryptophan is one of the eight essential amino acids and plays an important role in many biological processes. For its interaction with human health, environment and relevant commercial interest in biotechnology-based production, rapid and specific quantification method for this molecule accessible to common laboratories is badly needed. We herein reported a simple colorimetric method for free tryptophan quantification with 96-well-plate-level throughput. Our protocol firstly converted tryptophan to indole enzymatically by purified tryptophanases and then used reactivity of indole with hydroxylamine to form pink product with absorption peak at 530nm, enabling the quantification of tryptophan with simple spectrometry in just two hours. We presented that this method exhibited a linear detection range from 100μM to 600μM (R(2) = 0.9969) with no detection towards other naturally occurring tryptophan analogs or tryptophan residues in proteins. It was very robust in complicated biological samples, as demonstrated by quantifying the titer of 36 mutated tryptophan-producing strains with Pearson correlation coefficient of 0.93 in contrast to that measured by high performance liquid chromatography (HPLC). Our method should be potent for routine free tryptophan quantification in a high-throughput manner, facilitating studies in medicine, microbiology, food chemistry, metabolic engineering, etc. Copyright © 2017. Published by Elsevier B.V.

  5. Comparison of rapid colorimetric method with conventional method in the isolation of mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Oberoi A

    2004-01-01

    Full Text Available The aim of the study was to evaluate two methods (colorimetric and conventional for isolation of Mycobacterium tuberculosis. A total of 500 clinical specimens were processed by modified Petroff′s method and then inoculated into MB/BacT-240 system bottles and on LJ medium slopes. The specimens included 242 sputum, 95 gastric aspirates, 47 pleural fluids, 45 CSF, 32 urine, 18 pus, 11 bronchoalveolar lavage, 3 tissue, 2 stool, 2 lymphnode specimens, 2 synovial fluid and 1 bronchial wash specimens. The isolation rate was 16.4% by the colorimetric method and 2.2% by the conventional method. The mean detection time was 16 days and 26 days respectively. Among 36 direct smear positive samples, 63.9%(23/36 and 30%(11/36 were positive by colorimetric and conventional methods respectively. Out of 464 direct smear negative samples 12.9%(60/464 and 0.6%(3/464 were positive by colorimetric and conventional methods respectively. Therefore, colorimetric method enables rapid detection leading to early diagnosis and drug susceptibility testing.

  6. Visual and colorimetric methods for rapid determination of total tannins in vegetable raw materials

    Directory of Open Access Journals (Sweden)

    S. P. Kalinkina

    2016-01-01

    Full Text Available The article is dedicated to the development of rapid colorimetric method for determining the amount of tannins in aqueous extracts of vegetable raw materials. The sorption-based colorimetric test is determining sorption tannins polyurethane foam, impregnated of FeCl3, receiving on its surface painted in black and green color of the reaction products and the determination of their in sorbent matrix. Selectivity is achieved by determining the tannins specific interaction of polyphenols with iron ions (III. The conditions of sorption-colorimetric method: the concentration of ferric chloride (III, impregnated in the polyurethane foam; sorbent mass in the analytical cartridge; degree of loading his agent; the contact time of the phases. color scales have been developed for the visual determination of the amount of tannins in terms of gallic acid. Spend a digitized image obtained scales using computer program “Sorbfil TLC”, excluding a subjective assessment of the intensity of the color scale of the test. The results obtained determine the amount of tannins in aqueous extracts of vegetable raw rapid method using tablets and analytical cartridges. The results of the test determination of tannins with visual and densitometric analytical signal registration are compared to known methods. Spend a metrological evaluation of the results of determining the amount of tannins sorption rapid colorimetric methods. Time visual and densitometric rapid determination of tannins, taking into account the sample preparation is 25–30 minutes, the relative error does not exceed 28 %. The developed test methods for quantifying the content of tannins allow to exclude the use of sophisticated analytical equipment, carry out the analysis in non-laboratory conditions do not require highly skilled personnel.

  7. A Rapid Colorimetric Method Reveals Fraudulent Substitutions in Sea Urchin Roe Marketed in Sardinia (Italy).

    Science.gov (United States)

    Meloni, Domenico; Spina, Antonio; Satta, Gianluca; Chessa, Vittorio

    2016-06-25

    In recent years, besides the consumption of fresh sea urchin specimens, the demand of minimally-processed roe has grown considerably. This product has made frequent consumption in restaurants possible and frauds are becoming widespread with the partial replacement of sea urchin roe with surrogates that are similar in colour. One of the main factors that determines the quality of the roe is its colour and small differences in colour scale cannot be easily discerned by the consumers. In this study we have applied a rapid colorimetric method for reveal the fraudulent partial substitution of semi-solid sea urchin roe with liquid egg yolk. Objective assessment of whiteness (L*), redness (a*), yellowness (b*), hue (h*), and chroma (C*) was carried out with a digital spectrophotometer using the CIE L*a*b* colour measurement system. The colorimetric method highlighted statistically significant differences among sea urchin roe and liquid egg yolk that could be easily discerned quantitatively.

  8. Rapid quantitative analysis of lipids using a colorimetric method in a microplate format.

    Science.gov (United States)

    Cheng, Yu-Shen; Zheng, Yi; VanderGheynst, Jean S

    2011-01-01

    A colorimetric sulfo-phospho-vanillin (SPV) method was developed for high throughput analysis of total lipids. The developed method uses a reaction mixture that is maintained in a 96-well microplate throughout the entire assay. The new assay provides the following advantages over other methods of lipid measurement: (1) background absorbance can be easily corrected for each well, (2) there is less risk of handling and transferring sulfuric acid contained in reaction mixtures, (3) color develops more consistently providing more accurate measurement of absorbance, and (4) the assay can be used for quantitative measurement of lipids extracted from a wide variety of sources. Unlike other spectrophotometric approaches that use fluorescent dyes, the optimal spectra and reaction conditions for the developed assay do not vary with the sample source. The developed method was used to measure lipids in extracts from four strains of microalgae. No significant difference was found in lipid determination when lipid content was measured using the new method and compared to results obtained using a macro-gravimetric method.

  9. O-antigen and virulence profiling of Shiga toxin-producing Escherichia coli by a rapid and cost-effective DNA microarray colorimetric method

    Directory of Open Access Journals (Sweden)

    Beatriz eQuiñones

    2012-05-01

    Full Text Available Shiga toxin-producing Escherichia coli (STEC is a leading cause of foodborne illness worldwide. The present study developed the use of DNA microarrays with the ampliPHOX colorimetric method to rapidly detect and genotype STEC strains. A low-density 30-mer oligonucleotide DNA microarray was designed to target O-antigen gene clusters of eleven E. coli serogroups (O26, O45, O91, O103, O104, O111, O113, O121, O128, O145 and O157 that have been associated with the majority of STEC infections. In addition, the DNA microarray targeted eleven virulence genes, encoding adhesins, cytotoxins, proteases, and receptor proteins, which have been implicated in conferring increased ability to cause disease for STEC. Results from the validation experiments demonstrated that this microarray-based colorimetric method allowed for a rapid and accurate genotyping of STEC reference strains from environmental and clinical sources and from distinct geographical locations. Positive hybridization signals were detected only for probes targeting serotype and virulence genes known to be present in the STEC reference strains. Quantification analysis indicated that the mean pixel intensities of the signal for probes targeting O-antigen or virulence genes were at least three times higher when compared to the background. Furthermore, this microarray-based colorimetric method was then employed to genotype a group of E. coli isolates from watershed sediment and animal fecal samples that were collected from an important region for leafy-vegetable production in the central coast of California. The results indicated an accurate identification of O-type and virulence genes in the tested isolates and confirmed that the ampliPHOX colorimetric method with low density DNA microarrays enabled a fast assessment of the virulence potential of STEC using low-cost reagents and instrumentation.

  10. O-antigen and virulence profiling of Shiga toxin-producing Escherichia coli by a rapid and cost-effective DNA microarray colorimetric method

    OpenAIRE

    Beatriz eQuiñones; Swimley, Michelle S.; Koh-Eun eNarm; Patel, Ronak N.; Cooley, Michael B.; Mandrell, Robert E.

    2012-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a leading cause of foodborne illness worldwide. The present study developed the use of DNA microarrays with the ampliPHOX colorimetric method to rapidly detect and genotype STEC strains. A low-density 30-mer oligonucleotide DNA microarray was designed to target O-antigen gene clusters of eleven E. coli serogroups (O26, O45, O91, O103, O104, O111, O113, O121, O128, O145 and O157) that have been associated with the majority of STEC infections. ...

  11. A quick colorimetric method for total lipid quantification in microalgae.

    Science.gov (United States)

    Byreddy, Avinesh R; Gupta, Adarsha; Barrow, Colin J; Puri, Munish

    2016-06-01

    Discovering microalgae with high lipid productivity are among the key milestones for achieving sustainable biodiesel production. Current methods of lipid quantification are time intensive and costly. A rapid colorimetric method based on sulfo-phospho-vanillin (SPV) reaction was developed for the quantification of microbial lipids to facilitate screening for lipid producing microalgae. This method was successfully tested on marine thraustochytrid strains and vegetable oils. The colorimetric method results correlated well with gravimetric method estimates. The new method was less time consuming than gravimetric analysis and is quantitative for lipid determination, even in the presence of carbohydrates, proteins and glycerol. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Colorimetric method for the determination of hydralazine ...

    African Journals Online (AJOL)

    A colorimetric method was developed for the quantitative determination of hydralazine hydrochloride in dosage forms. The method was based on the formation of a hydrazone following a coupling reaction between hydralazine and vanillin in acidic condition and the spectrophotometric determination at the absorption ...

  13. A Wash-Free Homogeneous Colorimetric Immunoassay Method

    OpenAIRE

    Liu, Huiqiao; Rong, Pengfei; Jia, Hongwei; Yang, Jie; Dong, Bo; Dong, Qiong; Yang, Cejun; Hu, Pengzhi; Wang, Wei; Liu, Haitao; Liu, Dingbin

    2016-01-01

    Rapid and convenient biosensing platforms could be beneficial to timely diagnosis and treatment of diseases in virtually any care settings. Sandwich immunoassays, the most commonly used methods for protein detection, often rely on expensive tags such as enzyme and tedious wash and incubation procedures operated by skilled labor. In this report, we revolutionized traditional sandwich immunoassays by providing a wash-free homogeneous colorimetric immunoassay method without requirement of any se...

  14. A rapid colorimetric assay for mold spore germination using XTT tetrazolium salt

    Science.gov (United States)

    Carol A. Clausen; Vina W. Yang

    2011-01-01

    Current laboratory test methods to measure efficacy of new mold inhibitors are time consuming, some require specialized test equipment and ratings are subjective. Rapid, simple quantitative assays to measure the efficacy of mold inhibitors are needed. A quantitative, colorimetric microassay was developed using XTT tetrazolium salt to metabolically assess mold spore...

  15. Colorimetric deoxyribonucleic acid hybridization assay for rapid screening of Salmonella in foods: collaborative study.

    Science.gov (United States)

    Curiale, M S; Klatt, M J; Mozola, M A

    1990-01-01

    A collaborative study was performed in 11 laboratories to validate a colorimetric DNA hybridization (DNAH) method for rapid detection of Salmonella in foods. The method was compared to the standard culture method for detection of Salmonella in nonfat dry milk, milk chocolate, soy isolate, dried whole egg, ground black pepper, and raw ground turkey. Samples inoculated with high (0.4-2 cells/g) and low (0.04-0.2 cells/g) levels of Salmonella and uninoculated control samples were included in each food group analyzed. There was no significant difference in the proportion of samples positive by DNAH and culture procedure for any of the 6 foods. The colorimetric DNA hybridization assay screening method has been adopted official first action as a rapid screening method for detection of Salmonella in all foods.

  16. A Wash-Free Homogeneous Colorimetric Immunoassay Method.

    Science.gov (United States)

    Liu, Huiqiao; Rong, Pengfei; Jia, Hongwei; Yang, Jie; Dong, Bo; Dong, Qiong; Yang, Cejun; Hu, Pengzhi; Wang, Wei; Liu, Haitao; Liu, Dingbin

    2016-01-01

    Rapid and convenient biosensing platforms could be beneficial to timely diagnosis and treatment of diseases in virtually any care settings. Sandwich immunoassays, the most commonly used methods for protein detection, often rely on expensive tags such as enzyme and tedious wash and incubation procedures operated by skilled labor. In this report, we revolutionized traditional sandwich immunoassays by providing a wash-free homogeneous colorimetric immunoassay method without requirement of any separation steps. The proposed strategy was realized by controlling the growth of gold nanoparticles (AuNPs) to mediate the interparticle spacing in the protein-AuNP oligomers. We have demonstrated the successful in vitro detection of cancer biomarker in serum samples from patients with high clinical sensitivity and specificity.

  17. Development of Rapid and Economical Colorimetric Screening Method for p-Phenylenediamine in Variety of Biological Matrices and its Application to Eleven Fatal Cases of p-Phenylenediamine Poisoning.

    Science.gov (United States)

    Imran, Muhammad; Usman, Hafiz Faisal; Shafi, Humera; Sarwar, Muhammad; Tahir, Muhammad Ashraf

    2017-03-01

    A rapid colorimetric method for detection of p-phenylenediamine (PPD) in various biological samples is developed. The o-cresol test for acetaminophen detection has been modified to detect PPD in blood, urine, gastric contents, and liver. After precipitating protein with trichloroacetic acid solution (2 mL, 10% w/v), biological specimens were required to convert PPD metabolites to PPD by acid hydrolysis. Finally, o-cresol solution (1 mL, 1% w/v), hydrogen peroxide (200 μL, 3%v/v), and concentrated ammonium hydroxide (0.5 mL) were added in the biological samples. The presence of PPD was indicated by formation of violet color which was turned to bluish green color within 10-15 min. The limit of detection was found to be 2 mg/L in blood, urine, and gastric contents and 2 mg/Kg in liver. This method is also free from any potential interference by p-aminophenol, acetaminophen, and other amine drugs under test conditions. This method was successfully employed to thirteen fatal cases of PPD poisoning. © 2016 American Academy of Forensic Sciences.

  18. An alternative colorimetric method for the determination of ...

    African Journals Online (AJOL)

    ... could be routinely used for the determination of chloramphenicol in bulk drug and in different dosage forms. The advantage of the method is its speed and simplicity. Key words: Chloramphenicol, colorimetric assay, microbiological assay, p-dimethyl-aminobenzaldehyde. Trop J Pharm Res, December 2003; 2(2): 215-221 ...

  19. Evaluation of a direct colorimetric assay for rapid detection of ...

    African Journals Online (AJOL)

    Yemane Berhane

    bromide (MTT) for a rapid detection of rifampicin resistance. Methods: Sputum was inoculated directly into 7H9 .... a loopful of the corresponding broth on nutrient agar and incubating it at 370C for 24 hours before performing the .... and Training in Tropical Diseases (TDR). This study was part of the MSc thesis of DW at Addis ...

  20. Antitumor evaluation of epigallocatechin gallate by colorimetric methods

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Soon Ok [Korean Ginseng and Tobacco Research institute, Daejon (Korea, Republic of); Kim, Il Kwang; Baek, Seung Hwa; Han, Du Seok [Wonkwang Unvi., Iksan (Korea, Republic of)

    1998-08-01

    In the present study, we were evaluated cytotoxic effects of epigallocatechin gallate in human skin melanoma cells such as HTB-69. The light microscopic study showed morphological changes of the treated cells. Disruptions in cell organelles were determined by colorimetric methods; 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, neutral red (NR) assay and sulforhodamine B protein (SRB) as-say. These results suggest that epigallocatechin gallate retains a potential antitumor activity.

  1. Rapid, low level determination of silver(I) in drinking water by colorimetric-solid-phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Matteo P.; Porter, Marc D.; Fritz, James S

    2003-04-15

    A rapid, highly sensitive two-step procedure for the trace analysis of silver(I) is described. The method is based on: (1) the solid-phase extraction (SPE) of silver(I) from a water sample onto a disk impregnated with a silver-selective colorimetric reagent, and (2) the determination of the amount of complexed analyte extracted by the disk by diffuse reflectance spectroscopy (DRS). This method, called colorimetric-solid-phase extraction (C-SPE), was recently shown effective in determining low concentrations (0.1-5.0 mg/ml) of iodine and iodide in drinking water. This report extends C-SPE to the trace ({approx}4 {mu}g/l) level monitoring of silver(I) which is a biocide used on the International Space Station (ISS). The determination relies on the manually driven passage of a water sample through a polystyrene-divinylbenzene disk that has been impregnated with the colorimetric reagent 5-(p-dimethylaminobenzylidene) rhodanine (DMABR) and with an additive such as a semi-volatile alcohol (1,2-decanediol) or nonionic surfactant (Brij 30). The amount of concentrated silver(I) is then determined in a few seconds by using a hand-held diffuse reflectance spectrometer, with a total sample workup and readout time of {approx}60 s. Importantly, the additive induces the uptake of water by the disk, which creates a local environment conducive to silver(I) complexation at an extremely high concentration factor ({approx}800). There is no detectable reaction between silver(I) and impregnated DMABR in the absence of the additive. This strategy represents an intriguing new dimension for C-SPE in which additives, directly loaded in the disk material, provide a means to manipulate the reactivity of the impregnated reagent.

  2. A smartphone-based colorimetric reader coupled with a remote server for rapid on-site catechols analysis.

    Science.gov (United States)

    Wang, Yun; Li, Yuanyuan; Bao, Xu; Han, Juan; Xia, Jinchen; Tian, Xiaoyu; Ni, Liang

    2016-11-01

    The search of a practical method to analyze cis-diol-containing compounds outside laboratory settings remains a substantial scientific challenge. Herein, a smartphone-based colorimetric reader was coupled with a remote server for rapid on-site analysis of catechols. A smallest-scale 2×2 colorimetric sensor array composed of pH indicators and phenylboronic acid was configured. The array was able to distinguish 13 catechols at 6 serial concentrations, through simultaneous treatment via principal component analysis, hierarchical cluster analysis, and linear discriminant analysis. After both the discriminatory power of the array and the prediction ability of the partial least squares quantitative models were proved to be predominant, the smartphone was coupled to the remote server. All the ΔRGB data were uploaded to the remote server wherein linear discriminant analysis and partial least squares processing modules were established to provide qualitative discrimination and quantitative calculation, respectively, of the analytes in real time. The applicability of this novel method to a real-life scenario was confirmed by the on-site analysis of various catechols from a water sample of the Yangtze River; the feedback result in the smartphone showed the method was able to identify the catechols with 100% accuracy and predict the concentrations to within 0.706-2.240 standard deviation. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Tuning Toehold Length and Temperature to Achieve Rapid, Colorimetric Detection of DNA from the Disassembly of DNA-Gold Nanoparticle Aggregates.

    Science.gov (United States)

    Lam, Michael K; Gadzikwa, Tendai; Nguyen, Trang; Kausar, Abu; Alladin-Mustan, B Safeenaz; Sikder, Md Delwar; Gibbs-Davis, Julianne M

    2016-02-16

    Gold nanoparticles have been widely utilized to achieve colorimetric detection for various diagnostic applications. One of the most frequently used methods for DNA detection involves the aggregation of DNA-modified gold nanoparticles driven by target DNA hybridization. This process, however, is intrinsically slow, limiting its use in rapid diagnostics. Here we take advantage of the reverse process: the disassembly of preformed aggregates triggered by the addition of target DNA via a strand displacement mechanism. A systematic study of the dependence of the disassembly rate on temperature, with and without toeholds, has delivered a system that produces an extremely rapid colorimetric response. Furthermore, using an optimal toehold length of 5 nucleotides, target triggered disassembly is rapid over a wide range of ambient temperatures. Using this overhang system, simple visualization of low picomole amounts of target DNA is possible within 10 min at room temperature.

  4. Applicability of a colorimetric method for evaluation of lactic acid bacteria with probiotic properties.

    Science.gov (United States)

    Jung, Min Young; Lee, Jina; Park, Boyeon; Hwang, Hyelyeon; Sohn, Sung-Oh; Lee, Se Hee; Lim, Hyeong In; Park, Hae Woong; Lee, Jong-Hee

    2017-06-01

    Rapid colorimetric methods using various indicator reagents have been developed to monitor bacterial viability. Here, we examined the applicability of a method based on the reduction of resazurin or water-soluble tetrazolium salt-8 (WST-8) to screen lactic acid bacteria (LAB) for growth, tolerance against bile acid and low pH. The resazurin reduction test proved unsuitable for screening LAB such as Lactobacillus plantarum and Leuconostoc mesenteroides since it reacted with acid present in the cultures. LAB growth could be indirectly quantified by measuring WST-8 reduction. This method proved more sensitive and quickly results than counting bacterial colony forming units and turbidity at 600 nm in the presence of bile and acid. Our results suggested that the WST-8-based method could be useful for the characterization of growth and tolerance of the lactic acid producing bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Rapid and selective lead (II) colorimetric sensor based on azacrown ether-functionalized gold nanoparticles

    Science.gov (United States)

    Alizadeh, A.; Khodaei, M. M.; Karami, Ch; Workentin, M. S.; Shamsipur, M.; Sadeghi, M.

    2010-08-01

    A gold nanoparticle (AuNPs)-based simple and fast colorimetric sensor for selective detecting of Pb(II) in aqueous solution has been developed. Monodisperse AuNPs (approx. 2.0 nm diameter) has been prepared facilely and further modified with an alkanethiol-bearing monoazacrown ether terminus. These AuNPs are shown to selectively sense Pb2 + through color change, which is visually discernible by an appearance of the surface plasmon band (SPB) at 520 nm. The recognition mechanism is attributed to the unique structure of the monoazacrown ether attached to AuNPs and metal sandwich coordination between two azacrown ether moieties that are attached to separate nanoparticles. This inter-particle cross-linking results in an aggregation and apparent color change from brown to purple. Additionally, TEM experiments support the optical absorption data proving the aggregation between azacrown ether-capped gold nanoparticles. This AuNP-based colorimetric assay is a facile and robust method and allows fast detection of Pb2 + at ambient temperatures. More importantly, the developed technique does not utilize enzymatic reactions, light-sensitive dye molecules, lengthy protocols or sophisticated instrumentation.

  6. A new diatom growth inhibition assay using the XTT colorimetric method.

    Science.gov (United States)

    Jiang, Weina; Akagi, Takuya; Suzuki, Hidekazu; Takimoto, Ayaka; Nagai, Hiroshi

    2016-01-01

    Marine biofouling, which leads to significant operational stress and economic damage on marine infrastructures, is a major problem in marine related industries. Currently, the most common way to avoid marine biofouling involves the use of biocidal products in surface coatings. However, the need for environmentally friendly antibiofouling compounds has increased rapidly with the recent global prohibition of harmful antifoulants, such as tributyltin (TBT). In particular, periphytic diatoms have been shown to contribute significantly to biofilms, which play an important role in biofouling. Therefore, inhibiting the proliferation of fouling diatoms is a very important step in the prevention of marine biofouling. In this study, we developed a new, rapid, accurate, and convenient growth inhibition assay using the XTT colorimetric method to prevent the growth of the fouling periphytic diatom, Nitzschia amabilis Hidek. Suzuki (replaced synonym, Nitzschia laevis Hustedt). The feasibility of this method was verified by determining the growth inhibition activities of two standard photosynthetic inhibitors, DCMU and CuSO4. However, neither inhibitor had any cytotoxic activities at the range of concentrations tested. Moreover, this method was applied by screening and purification of herbicidic but non-cytotoxic compounds from cyanobacteria extracts. Our results demonstrate the utility of this newly established growth inhibition assay for the identification of marine anti-biofouling compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. A colorimetric assay of 1-aminocyclopropane-1-carboxylate (ACC) based on ninhydrin reaction for rapid screening of bacteria containing ACC deaminase.

    Science.gov (United States)

    Li, Z; Chang, S; Lin, L; Li, Y; An, Q

    2011-08-01

    1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity is an efficient marker for bacteria to promote plant growth by lowering ethylene levels in plants. We aim to develop a method for rapidly screening bacteria containing ACC deaminase, based on a colorimetric ninhydrin assay of ACC. A reliable colorimetric ninhydrin assay was developed to quantify ACC using heat-resistant polypropylene chimney-top 96-well PCR plates, having the wells evenly heated in boiling water, preventing accidental contamination from boiling water and limiting evaporation. With this method to measure bacterial consumption of ACC, 44 ACC-utilizing bacterial isolates were rapidly screened out from 311 bacterial isolates that were able to grow on minimal media containing ACC as the sole nitrogen source. The 44 ACC-utilizing bacterial isolates showed ACC deaminase activities and belonged to the genus Burkholderia, Pseudomonas or Herbaspirillum. Determination of bacterial ACC consumption by the PCR-plate ninhydrin-ACC assay is a rapid and efficient method for screening bacteria containing ACC deaminase from a large number of bacterial isolates. The PCR-plate ninhydrin-ACC assay extends the utility of the ninhydrin reaction and enables a rapid screening of bacteria containing ACC deaminase from large numbers of bacterial isolates. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

  8. Rapid colorimetric sensing platform for the detection of Listeria monocytogenes foodborne pathogen.

    Science.gov (United States)

    Alhogail, Sahar; Suaifan, Ghadeer A R Y; Zourob, Mohammed

    2016-12-15

    Listeria monocytogenes is a serious cause of human foodborne infections worldwide, which needs spending billions of dollars for inspection of bacterial contamination in food every year. Therefore, there is an urgent need for rapid, in-field and cost effective detection techniques. In this study, rapid, low-cost and simple colorimetric assay was developed using magnetic nanoparticles for the detection of listeria bacteria. The protease from the listeria bacteria was detected using D-amino acid substrate. D-amino acid substrate was linked to the carboxylic acid on the magnetic nanoparticles using EDC/NHS chemistry. The cysteine residue at the C-terminal of the substrate was used for the self-assembled monolayer formation on the gold sensor surface, which in turn the black magnetic nanobeads will mask the golden color. The color will change from black to golden color upon the cleavage of the specific peptide sequence by the Listeria protease. The sensor was tested with serial dilutions of Listeria bacteria. It was found that the appearance of the gold surface area is proportional to the bacterial concentrations in CFU/ml. The lowest detection limit of the developed sensor for Listeria was found to be 2.17×10(2) colony forming unit/ml (CFU/ml). The specificity of the biosensor was tested against four different foodborne associated bacteria (Escherichia coli, Salmonella, Shigella flexnerii and Staphylococcus aureus). Finally, the sensor was tested with artificially spiked whole milk and ground meat spiked with listeria. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A colorimetric and spectrophotometric method for in vitro susceptibility testing of Aspergillus species against caspofungin.

    NARCIS (Netherlands)

    Dorsthorst, D.T.A. te; Zwaaftink, R.B.; Rijs, A.J.M.M.; Meletiadis, J.; Verweij, P.E.

    2007-01-01

    The in vitro susceptibility of 45 Aspergillus fumigatus, Aspergillus flavus and Aspergillus terreus isolates against caspofungin (CAS) was assessed by the CLSI reference method with spectrophotometric reading and by a colorimetric method that employed the dye MTT. Perfect agreement was found between

  10. A microdevice for rapid, monoplex and colorimetric detection of foodborne pathogens using a centrifugal microfluidic platform.

    Science.gov (United States)

    Sayad, Abkar; Ibrahim, Fatimah; Mukim Uddin, Shah; Cho, Jongman; Madou, Marc; Thong, Kwai Lin

    2018-02-15

    Outbreaks of foodborne diseases have become a global health concern; hence, many improvements and developments have been made to reduce the risk of food contamination. We developed a centrifugal microfluidic automatic wireless endpoint detection system integrated with loop mediated isothermal amplification (LAMP) for monoplex pathogen detection. Six identical sets were designed on the microfluidic compact disc (CD) to perform 30 genetic analyses of three different species of foodborne pathogens. The consecutive loading, mixing, and aliquoting of the LAMP primers/reagents and DNA sample solutions were accomplished using an optimized square-wave microchannel, metering chambers and revulsion per minute (RPM) control. We tested 24 strains of pathogenic bacteria (Escherichia coli, Salmonella spp and Vibrio cholerae), with 8 strains of each bacterium, and performed DNA amplification on the microfluidic CD for 60min. Then, the amplicons of the LAMP reaction were detected using the calcein colorimetric method and further analysed via the developed electronic system interfaced with Bluetooth wireless technology to transmit the results to a smartphone. The system showed a limit of detection (LOD) of 3 × 10-5ngμL-1 DNA by analysing the colour change when tested with chicken meat spiked with the three pathogenic bacteria. Since the entire process was performed in a fully automated way and was easy to use, our microdevice is suitable for point-of-care (POC) testing with high simplicity, providing affordability and accessibility even to poor, resource-limited settings. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A highly sensitive and selective aptamer-based colorimetric sensor for the rapid detection of PCB 77.

    Science.gov (United States)

    Cheng, Ruojie; Liu, Siyao; Shi, Huijie; Zhao, Guohua

    2018-01-05

    A highly sensitive, specific and simple colorimetric sensor based on aptamer was established for the detection of polychlorinated biphenyls (PCB 77). The use of unmodified gold nanoparticles as a colorimetric probe for aptamer sensors enabled the highly sensitive and selective detection of polychlorinated biphenyls (PCB 77). A linear range of 0.5nM to 900nM was obtained for the colorimetric assay with a minimum detection limit of 0.05nM. In addition, by the methods of circular dichroism, UV and naked eyes, we found that the 35 base fragments retained after cutting 5 bases from the 5 'end of aptamer plays the most significant role in the PCB 77 specific recognition process. We found a novel way to truncated nucleotides to optimize the detection of PCB 77, and the selected nucleotides also could achieve high affinity with PCB 77. At the same time, the efficient detection of the PCB 77 by our colorimetric sensor in the complex environmental water samples was realized, which shows a good application prospect. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Evaluation of micro-colorimetric lipid determination method with samples prepared using sonication and accelerated solvent extraction methods.

    Science.gov (United States)

    Billa, Nanditha; Hubin-Barrows, Dylan; Lahren, Tylor; Burkhard, Lawrence P

    2014-02-01

    Two common laboratory extraction techniques were evaluated for routine use with the micro-colorimetric lipid determination method developed by Van Handel (1985) [2] and recently validated for small samples by Inouye and Lotufo (2006) [1]. With the accelerated solvent extraction method using chloroform:methanol solvent and the colorimetric lipid determination method, 28 of 30 samples had significant proportional bias (α=1%, determined using standard additions) and 1 of 30 samples had significant constant bias (α=1%, determined using Youden Blank measurements). With sonic extraction, 0 of 6 samples had significant proportional bias (α=1%) and 1 of 6 samples had significant constant bias (α=1%). These demonstrate that the accelerated solvent extraction method with chloroform:methanol solvent system creates an interference with the colorimetric assay method, and without accounting for the bias in the analysis, inaccurate measurements would be obtained. Published by Elsevier B.V.

  13. Analyte-induced photoreduction method for visual and colorimetric detection of tyrosine

    Energy Technology Data Exchange (ETDEWEB)

    Satheeshkumar, Elumalai; Yang, Jyisy, E-mail: jyisy@dragon.nchu.edu.tw

    2015-06-16

    Highlights: • New detection scheme for detection of tyrosine is developed. • Photoactivity of tyrosine is used to form color nanoparticles selectively. • Detection step is simple and effective allowing rapid screening. • Highly sensitive and selective in detection of tyrosine. - Abstract: A new method based on photochemical formation of silver nanoparticles (AgNPs) was developed for detection of tyrosine (Tyr). To selectively detect Tyr and to simplify the detection procedure, the photoactivity of Tyr was utilized to trigger the photochemical reduction in production of AgNPs. The drastic change of solution color caused by the surface plasmon resonance (SPR) absorption band of the formed AgNPs was used to extract the quantitative information of Tyr. This developed method is simple in detection, while both the sensitivity and selectivity are significant improved. Meanwhile, the solution color was changed from colorless to dark yellow after the formation of AgNPs, which allows a much higher sensitivity in visual identification when compared with the SPR band shifting technique commonly, used in conventional colorimetric methods. To optimize the detection system and to understand the mechanism in this proposed method, parameters such as irradiation time, intensity of light source, and the concentration of Tyr were systematically examined. Results indicated that these factors mainly affected the reaction rate of photoreduction. The morphologies of the formed AgNPs were similar, but with small differences in particle sizes. In the examination of selectivity, sixteen other amino acids were examined. Results indicated that only amino acids of tryptophan, cysteine and histidine are photoactive and possess potential interferences in analysis of Tyr. Quantitative studies indicated that a linear response up to 10 μM with a detection limit of 100 nM could be obtained. For visually detection, color change could be observed with a concentration as low as 500 nM of Tyr.

  14. A Colorimetric Method for the Determination of the Exhaustion Level of Granular Activated Carbons Used in Rum Production

    Directory of Open Access Journals (Sweden)

    Harold Crespo Sariol

    2016-09-01

    Full Text Available Spectrophotometric measurement applied on saturated granular activated carbon (GAC is not yet explored. A colorimetric method in the visible range has been developed in order to determine the exhaustion level of GAC used in rum production. Aqueous ammonia solution has been used as an indicative agent to determine the extraction rate of taste compounds within the rum production process and the exhaustion degree of the GAC. The colorimetric results showed excellent correlation with the iodine number and the contact pH. The proposed colorimetric method opens possibilities for rum producers to improve the management and economical use of the activated carbon at the industrial scale.

  15. Rapid determination of trace copper in animal feed based on micro-plate colorimetric reaction and statistical partitioning correction.

    Science.gov (United States)

    Niu, Yiming; Wang, Jiayi; Zhang, Chi; Chen, Yiqiang

    2017-04-15

    The objective of this study was to develop a micro-plate based colorimetric assay for rapid and high-throughput detection of copper in animal feed. Copper ion in animal feed was extracted by trichloroacetic acid solution and reduced to cuprous ion by hydroxylamine. The cuprous ion can chelate with 2,2'-bicinchoninic acid to form a Cu-BCA complex which was detected with high sensitivity by micro-plate reader at 354nm. The whole assay procedure can be completed within 20min. To eliminate matrix interference, a statistical partitioning correction approach was proposed, which makes the detection of copper in complex samples possible. The limit of detection was 0.035μg/mL and the detection range was 0.1-10μg/mL of copper in buffer solution. Actual sample analysis indicated that this colorimetric assay produced results consistent with atomic absorption spectrometry analysis. These results demonstrated that the developed assay can be used for rapid determination of copper in animal feed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Elevated-temperature, colorimetric, monoclonal, enzyme-linked immunosorbent assay for rapid screening of Salmonella in foods: collaborative study.

    Science.gov (United States)

    Eckner, K F; Dustman, W A; Curiale, M S; Flowers, R S; Robison, B J

    1994-01-01

    A collaborative study was performed by 30 laboratories in 3 sets of trials to validate a modified colorimetric monoclonal enzyme-linked immunosorbent assay (ELISA) method for Salmonella detection. The modifications to the current methodology included incubation of enrichments and post-enrichments at an elevated temperature, addition of novobiocin to the M-broth post-enrichment, and elimination of the centrifugation and agitation steps. Five artificially contaminated foods (nonfat dry milk, milk chocolate, dried egg, ground black pepper, and soy flour) and 1 naturally contaminated food (raw ground turkey) were analyzed. The artificially contaminated foods were inoculated with individual Salmonella serotypes at a high (10-50 cells/25 g) and low (1-5 cells/25 g) contamination level. Results from the modified ELISA method were compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method. In 2 of the food products, milk chocolate and pepper, a number of laboratories isolated Salmonella from un-inoculated control samples, thus invalidating their data. As a result, there were too few laboratories remaining with valid data, and these foods were repeated. In the completed study, there were 11 false negative results obtained by the modified ELISA method, while there were 28 false negatives produced by the BAM/AOAC procedure. There were 11 ELISA positive assays which could not be confirmed by culture methods. Statistically, there were no differences between the modified, colorimetric, monoclonal ELISA and the reference culture method in all foods except raw turkey, where the ELISA method was more productive. The colorimetric monoclonal enzyme immunoassay (Salmonella-Tek) method for detecting Salmonella in all foods has been adopted first action by AOAC INTERNATIONAL.

  17. A Universal Fast Colorimetric Method for DNA Signal Detection with DNA Strand Displacement and Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xin Li

    2015-01-01

    Full Text Available DNA or gene signal detection is of great significance in many fields including medical examination, intracellular molecular monitoring, and gene disease signal diagnosis, but detection of DNA or gene signals in a low concentration with instant visual results remains a challenge. In this work, a universal fast and visual colorimetric detection method for DNA signals is proposed. Specifically, a DNA signal amplification “circuit” based on DNA strand displacement is firstly designed to amplify the target DNA signals, and then thiol modified hairpin DNA strands and gold nanoparticles are used to make signal detection results visualized in a colorimetric manner. If the target DNA signal exists, the gold nanoparticles aggregate and settle down with color changing from dark red to grey quickly; otherwise, the gold nanoparticles’ colloids remain stable in dark red. The proposed method provides a novel way to detect quickly DNA or gene signals in low concentrations with instant visual results. When applied in real-life, it may provide a universal colorimetric method for gene disease signal diagnosis.

  18. BIOORGANIC CONCEPTS INVOLVED IN THE DETERMINATION OF GLUCOSE, CHOLESTEROL AND TRIGLYCERIDES IN PLASMA USING THE ENZYMATIC COLORIMETRIC METHOD

    National Research Council Canada - National Science Library

    Menezes, Fabrício G; Neves, Ana C. O; Lima, Djalan F. de; Lourenço, Sheeza D; Silva, Lilian C. da; Lima, Kássio M. G. de

    2015-01-01

    .... In this proposal, several aspects related to analyses of glucose, cholesterol and triglycerides using the enzymatic colorimetric method were involved, and the findings have at least two relevant implications...

  19. An improved colorimetric method for the determination of proline in the presence of other ninhydrin-positive compounds

    Science.gov (United States)

    Wren, J. J.; Wiggall, P. H.

    1965-01-01

    1. The conditions required for sensitive and specific colorimetric determination of proline with acidified ninhydrin were investigated. 2. A method applicable to protein samples was developed. 3. The only compound found to interfere appreciably was a hydroxyproline. PMID:14342233

  20. Colorimetric determination of nitrate plus nitrite in water by enzymatic reduction, automated discrete analyzer methods

    Science.gov (United States)

    Patton, Charles J.; Kryskalla, Jennifer R.

    2011-01-01

    This report documents work at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) to validate enzymatic reduction, colorimetric determinative methods for nitrate + nitrite in filtered water by automated discrete analysis. In these standard- and low-level methods (USGS I-2547-11 and I-2548-11), nitrate is reduced to nitrite with nontoxic, soluble nitrate reductase rather than toxic, granular, copperized cadmium used in the longstanding USGS automated continuous-flow analyzer methods I-2545-90 (NWQL laboratory code 1975) and I-2546-91 (NWQL laboratory code 1979). Colorimetric reagents used to determine resulting nitrite in aforementioned enzymatic- and cadmium-reduction methods are identical. The enzyme used in these discrete analyzer methods, designated AtNaR2 by its manufacturer, is produced by recombinant expression of the nitrate reductase gene from wall cress (Arabidopsis thaliana) in the yeast Pichia pastoris. Unlike other commercially available nitrate reductases we evaluated, AtNaR2 maintains high activity at 37°C and is not inhibited by high-phenolic-content humic acids at reaction temperatures in the range of 20°C to 37°C. These previously unrecognized AtNaR2 characteristics are essential for successful performance of discrete analyzer nitrate + nitrite assays (henceforth, DA-AtNaR2) described here.

  1. Colorimetric visualization of tin corrosion: A method for early stage corrosion detection on printed circuit boards

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2017-01-01

    circuit board assembly (PCBA) provides a basis for the mechanistic understanding of PCBA corrosion failures and leak current tracks which eventually can lead to electrochemical migration. This paper presents a method for identification of such failures at the early stage of corrosion by using...... a colorimetric tin ion indicator applied as a gel. The examples provided in this paper include visualization of corrosion caused by weak organic acids found in solder fluxes, corrosion profiling on the PCBAs after climatic device level testing, and failure analysis of field returns....

  2. Standard test method for lead in the atmosphere by colorimetric dithizone procedure

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Determination of low levels of lead in the atmosphere using a very selective dithizone colorimetric procedures is described. Particulate lead (that collected on a 0.45-..mu..m membrane filter) and vaporous lead (that passing through the 0.45-..mu..m filter) are determined separately. The method as described is without interference from 20 ..mu..g of Bi, 10 ..mu..g of Tl(I), 100 ..mu..g of Sn(II), and 200 ..mu..g of In(III).

  3. An overview of colorimetric assay methods used to assess survival or proliferation of mammalian cells.

    Science.gov (United States)

    Vega-Avila, Elisa; Pugsley, Michael K

    2011-01-01

    The aim of this review is to briefly describe some colorimetric methods that are commonly used to evaluate a new chemical entity (NCE) on cell cultures in non-clinical oncology discovery research. These methods have the distinct advantage over other techniques in that they can be applied and used in a cell monolayer or a suspension culture. Both protein assay determination and cell viability assays may be conducted using these culture systems. The viability of cell cultures is routinely assessed by utilizing the metabolic capacity of cells which biochemically convert chemicals (usually color dyes) which can then be conveniently measured at specific wavelengths using a multi-well plate reader. Resazurin (Alamar Blue) is an example of one of these metabolically active compounds. Resazurin is a nontoxic dye that can also be used to measure migration and cellular invasion without resorting to sacrifice of the cells during the test procedure. Another is 5-bromo-2-deoxyuridine (bromodeoxyuridine or BrdU) which is a thymidine analog that incorporates into the DNA of dividing cells during the S-phase of the cell cycle. We will also discuss the colorimetric version of the traditional 3H-thymidine incorporation and immunoenzymatic assay used to measure DNA synthesis and its application to discovery research.

  4. Single-layer MnO2 nanosheets for sensitive and selective detection of glutathione by a colorimetric method

    Science.gov (United States)

    Di, Weihua; Zhang, Xiang; Qin, Weiping

    2017-04-01

    The rapid, sensitive and selective detection of glutathione (GSH) is of great importance in the biological systems. In this work, a template-free and one-step method was used to synthesize the single-layer MnO2 nanosheets via a redox reaction. The resulting product was characterized by XRD, TEM, FTIR, XPS and UV-vis absorption. The addition of GSH results in the change of solution color depth owing to the occurrence of a redox reaction between MnO2 and GSH, enabling colorimetric detection of GSH. At a pH of 3.6, the proposed sensor gives a linear calibration over a GSH concentration range of 10-100 μM, with a rapid response of less than 2 min and a low detection limit of 0.5 μM. The relative standard deviation for seven repeated determinations of GSH is lower than 5.6%. Furthermore, the chemical response of the synthesized MnO2 nanosheets toward GSH is selective. Owing to the advantages with good water solubility, rapid response, high sensitivity, good biocompatibility and operation simplicity, this two-dimensional MnO2-based sensing material might be potential for detecting GSH in biological applications.

  5. High-performance peroxidase mimics for rapid colorimetric detection of H2O2 and glucose derived from perylene diimides functionalized Co3O4 nanoparticles.

    Science.gov (United States)

    Ding, Yanan; Chen, Miaomiao; Wu, Kaili; Chen, Mingxing; Sun, Lifang; Liu, Zhenxue; Shi, Zhiqiang; Liu, Qingyun

    2017-11-01

    N,N'-di-caboxy methyl perylene diimides (PDI), as one of the most promising functional materials in optional chemosensing, was first used to combine with Co3O4 nanoparticles through a facile two-step hydrothermal method and obtain the PDI functionalized Co3O4 nanocomposites (PDI-Co3O4 NCs). PDI-Co3O4 NCs were characterized by a series of technical analysis including transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), respectively. The experimental results indicated that the as-prepared PDI-Co3O4 NCs possessed the higher peroxidase-like activity than that of Co3O4 nanoparticles without PDI, and could rapidly catalyze oxidation reaction of the chromogenic substrate TMB in the presence of H2O2 to a blue product (oxTMB) observed by the naked eye. The improved catalytic activity of PDI-Co3O4 NCs for colorimetric reactions could be attributed to the synergistic effects of PDI and Co3O4 nanoparticles. On the basis of these experimental results, a convenient colorimetric system based on PDI-Co3O4 as enzyme mimic that is highly sensitive and selective was developed for glucose detection. Meanwhile, the electron transfer between H2O2 and TMB was responsible for the oxidation of TMB. The present work demonstrates a general strategy for the design of organic molecules functionalized oxide for different applications, such as nanocatalysts, biosensors and nanomedicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Relationships between ytterbium precipitation assay, colorimetric ...

    African Journals Online (AJOL)

    vitro biological activities of tannins and the commonly used, rapid colorimetric and gravimetric assays of phenolic concentration was of interest. An in vitro gas production bioassay was used to assess the potential biological effect of tannins by incubating tree fruits with and without tannin-binding PEG. Material and Methods.

  7. [Study on the counting of Streptococcus mutans, Streptococcus sanguis, Haemophilus actinomycetemcomitans by methyl thiazolyl tetrazolium colorimetric method].

    Science.gov (United States)

    Wang, Zhong-Chao; Fan, Li-Yuan; Jiang, Jun-Qiang; Cai, Wei; Ding, Yi

    2010-06-01

    To explore the feasibility of methyl thiazolyl tetrazolium (MTT) colorimetric method and the applied condition for the normal bacteria in the mouth, as Streptococcus mutans (S. mutans), Streptococcus sanguis (S. sanguis), Haemophilus actinomycetemcomitans (H. actinomycetemcomitans). Colony forming units (CFU) which was the standard antitheses was used to count bacteria. This study would gain some parameters by changing wavelength, reactive time, dosage and so on. MTT colorimetric method was applied in the counting of S. mutans, S. sanguis and H. actinomycetemcomitans. When counting S. mutans, the best wavelength was 510 nm, the best range was 1.5 x 10(5) - 1.0 x 10(7) CFU x mL(-1). When counting S. sanguis, the best wavelength was 545 nm, the best range was 1.5 x 10(5) - 2.0 x 10(7) CFU x mL(-1). When counting H. actinomycetemcomitans, the best wavelength was 557 nm, the best range was 1.0 x 10(6) - 5.0 x 10(7) CFU x mL(-1). MTT colorimetric method can be used for different aged S. mutans, S. sanguis and H. actinomycetemcomitans. Oral bacteria could be counted by MTT colorimetric method, which is fast and convenient.

  8. Rapid methods for detection of bacterial resistance to antibiotics.

    Science.gov (United States)

    March-Rosselló, Gabriel Alberto

    2017-03-01

    The most widely used antibiotic susceptibility testing methods in Clinical Microbiology are based on the phenotypic detection of antibiotic resistance by measuring bacterial growth in the presence of the antibiotic being tested. These conventional methods take typically 24hours to obtain results. Here we review the main techniques for rapid determination of antibiotic susceptibility. Data obtained with different methods such as molecular techniques, microarrays, commercial methods used in work routine, immunochromatographic methods, colorimetric methods, image methods, nephelometry, MALDI-TOF mass spectrometry, flow cytometry, chemiluminescence and bioluminescence, microfluids and methods based on cell disruption are analysed in detail. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  9. A convenient method for synthesis of glyconanoparticles for colorimetric measuring carbohydrate-protein interactions

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Yen-Jun [Faculty of Engineering, University of Georgia, Athens, GA 30602 (United States); Zhou, Xichun, E-mail: xichunz@adatech.com [ADA Technologies, Inc., 8100 Shaffer Parkway, Ste 130, Littleton, CO 80127-4107 (United States); Pan, Zhengwei [Faculty of Engineering, University of Georgia, Athens, GA 30602 (United States); Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States); Turchi, Craig [ADA Technologies, Inc., 8100 Shaffer Parkway, Ste 130, Littleton, CO 80127-4107 (United States)

    2009-11-06

    Carbohydrate functionalized nanoparticles, i.e., the glyconanoparticles, have wide application ranging from studies of carbohydrate-protein interactions, in vivo cell imaging, biolabeling, etc. Currently reported methods for preparation of glyconanoparticles require multi-step modifications of carbohydrates moieties to conjugate to nanoparticle surface. However, the required synthetic manipulations are difficult and time consuming. We report herewith a simple and versatile method for preparing glyconanoparticles. This method is based on the utilization of clean and convenient microwave irradiation energy for one-step, site-specific conjugation of unmodified carbohydrates onto hydrazide-functionalized Au nanoparticles. A colorimetric assay that utilizes the ensemble of gold glyconanoparticles and Concanavalin A (ConA) was also presented. This feasible assay system was developed to analyze multivalent interactions and to determine the dissociation constant (K{sub d}) for five kind of Au glyconanoparticles with lectin. Surface plasmon changes of the Au glyconanoparticles as a function of lectin-carbohydrate interactions were measured and the dissociation constants were determined based on non-linear curve fitting. The strength of the interaction of carbohydrates with ConA was found to be as follows: maltose > mannose > glucose > lactose > MAN5.

  10. A Colorimetric Method for Monitoring Tryptic Digestion Prior to Shotgun Proteomics

    Science.gov (United States)

    Somiari, Richard I.; Renganathan, Kutralanathan; Wolfe, Steven; Somiari, Stella B.

    2014-01-01

    Tryptic digestion is an important preanalytical step in shotgun proteomics because inadequate or excessive digestion can result in a failed or incomplete experiment. Unfortunately, this step is not routinely monitored before mass spectrometry because methods available for protein digestion monitoring either are time/sample consuming or require expensive equipment. To determine if a colorimetric method (ProDM Kit) can be used to identify the extent of tryptic digestion that yields the best proteomics outcome, plasma and serum digested for 8 h and 24 h were screened with ProDM, Bioanalyzer, and LC/MS/MS, and the effect of digestion on the number of proteins identified and sequence coverage was compared. About 6% and 16% less proteins were identified when >50% of proteins were digested in plasma and serum, respectively, compared to when ~46% of proteins were digested. Average sequence coverage for albumin, haptoglobin, and serotransferrin after 2 h, 8 h, and 24 h digestion was 52%, 45%, and 45% for serum and 54%, 47%, and 42% for plasma, respectively. This paper reiterates the importance of optimizing the tryptic digestion step and demonstrates the extent to which ProDM can be used to monitor and standardize protein digestion to achieve better proteomics outcomes. PMID:24678421

  11. A colorimetric method for lysyl oxidase activity in copper deficient rats fed a high fructose diet

    Energy Technology Data Exchange (ETDEWEB)

    Werman, M.J.; Bhathena, S.J. (Dept. of Agriculture, Beltsville, MD (United States))

    1991-03-11

    Lysyl oxidase is involved in initiating cross link formation in collagen and elastin. The activity of lysyl oxidase is traditionally assessed by the tritium released assay. The authors describe a simplified and modified method for measuring lysyl oxidase activity in rats, based on measuring ammonia release according to the Bertholet colorimetric reaction. Lysyl oxidase activity was measured in copper deficient rats using this method. Sixteen weanling Sprague Dawley male rats were fed for four weeks either copper adequate or copper deficient diets containing 62% fructose. Copper deficiency was confirmed by significant low copper levels in heart, brain, liver and skin, and by nondetectable levels of ceruloplasmin. Lysyl oxidase activity was significantly lower in heart and skin of rats fed a copper deficient diet compared to those fed a copper adequate diet. No significant difference in activity was observed in brain tissue. A correlation was not observed between decreased tissue copper levels and decreased lysyl oxidase activity. Thus, the determination of ammonia liberated during lysyl oxidase activity may serve as an effective tool in assessing lysyl oxidase activity.

  12. Application of the S-CIELAB color model to processed and calibrated images with a colorimetric dithering method

    Science.gov (United States)

    Chorro, E.; Perales, E.; de Fez, D.; Luque, M. J.; Martínez-Verdú, F. M.

    2007-06-01

    This work uses the S-CIELAB color model to compare images that have been calibrated and processed using a colorimetric dithering method which simulates increments in viewing distance. Firstly, we obtain XYZ calibrated images by applying the appropriate color transformations to the original images. These transformations depend on whether the image is viewed on a display device or encoded by a capture device, for example. Secondly, we use a colorimetric dithering method consisting of a partitive additive mixing of XYZ tristimulus values. The number of dithered pixels depends on simulated viewing distance. The dithered tristimulus values are transformed to digital data to observe the dithering effects in the image. Finally, we predict color differences using the S-CIELAB model as color appearance model for images. Moreover, this paper proposes some applications of this method to artistic and industrial problems where one must compare two images that appear different at close viewing distance, but match when they are seen from afar.

  13. Multicentre laboratory validation of the colorimetric redox indicator (CRI) assay for the rapid detection of extensively drug-resistant (XDR) Mycobacterium tuberculosis.

    Science.gov (United States)

    Martin, Anandi; Paasch, Fabienne; Docx, Sven; Fissette, Krista; Imperiale, Belen; Ribón, Wellman; González, Liliana Andrea; Werngren, Jim; Engström, Anna; Skenders, Girts; Juréen, Pontus; Hoffner, Sven; Del Portillo, Patricia; Morcillo, Nora; Palomino, Juan Carlos

    2011-04-01

    To perform a multicentre study to evaluate the performance of the colorimetric redox indicator (CRI) assay and to establish the MICs and critical concentrations of rifampicin, isoniazid, ofloxacin, kanamycin and capreomycin. The study was carried out in two phases. Phase I determined the MIC of each drug. Phase II established critical concentrations for the five drugs tested by the CRI assay compared with the conventional proportion method. Phase I: a strain was considered resistant by the CRI assay if the MIC was ≥0.5 mg/L for rifampicin, ≥0.25 mg/L for isoniazid, ≥4.0 mg/L for ofloxacin and ≥5.0 mg/L for kanamycin and capreomycin. Sensitivity was 99.1% for isoniazid and 100% for the other drugs and specificity was 97.9% for capreomycin and 100% for the other drugs. Phase II: the critical concentration was 0.5 mg/L for rifampicin, 0.25 mg/L for isoniazid, 2.0 mg/L for ofloxacin and 2.5 mg/L for kanamycin and capreomycin giving an overall accuracy of 98.4%, 96.6%, 96.7%, 98.3% and 90%, respectively. Results demonstrate that the CRI assay is an accurate method for the rapid detection of XDR Mycobacterium tuberculosis. The CRI assay is faster than the conventional drug susceptibility testing method using solid medium, has the same turnaround time as the BACTEC MGIT 960 system, but is less expensive, and could be an adequate method for low-income countries.

  14. Tentative method of test for lead in the atmosphere by colorimetric dithizone procedure. [Dithizone: Spectrophotometrically

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    Determination of low levels of atmospheric lead with separate measurement of particulate lead and vaporous lead isdescribed. Particulate lead is collected on an efficiency filter, and vaporous lead is that which will pass through a 0.45 ..mu..m membrane filter or its equivalent and includes various tetra-alkyl lead compounds or their partially decomposed products, or both. After separation, the particulate lead sample is digested with nitric and perchloric acids, and the dissolved lead is determined by a colorimetric dithizone procedure. The lead passing through the 0.45 ..mu..m membrane filter is absorbed on activated carbon. The method is intended primarily for measuring weekly averages of vaporous lead in ambient air at concentrations below 0.5 ..mu..g/m/sup 3/ and particulate lead in air at concentrations of 0.01 to 10.0 ..mu..g/m/sup 3/. Interference with the dithizone complex are noted for Bi, Sn/sup 2 +/, Tl/sup +/, and In. Since volatile organic compounds of these metals are not normally found in ambient air or they are removed by filters, these elements do not generally interfere with the determination of vaporous lead. A double extraction carried out at a higher pH will eliminate these interferences from the determination of particulate lead. (BLM)

  15. BIOORGANIC CONCEPTS INVOLVED IN THE DETERMINATION OF GLUCOSE, CHOLESTEROL AND TRIGLYCERIDES IN PLASMA USING THE ENZYMATIC COLORIMETRIC METHOD

    OpenAIRE

    Menezes, Fabrício G.; Neves, Ana C. O.; Lima,Djalan F. de; Lourenço, Sheeza D.; Lilian C. da Silva; Kássio M. G. Lima

    2015-01-01

    Bioorganic and biological chemistry have been found to be highly motivating to undergraduate students and in this context, biochemical blood parameter analysis emerges as highly attractive content. In this proposal, several aspects related to analyses of glucose, cholesterol and triglycerides using the enzymatic colorimetric method were involved, and the findings have at least two relevant implications: i) introducing students to connections between organic chemistry and biology based on enzy...

  16. Method for estimating effects of unknown correlations in spectral irradiance data on uncertainties of spectrally integrated colorimetric quantities

    Science.gov (United States)

    Kärhä, Petri; Vaskuri, Anna; Mäntynen, Henrik; Mikkonen, Nikke; Ikonen, Erkki

    2017-08-01

    Spectral irradiance data are often used to calculate colorimetric properties, such as color coordinates and color temperatures of light sources by integration. The spectral data may contain unknown correlations that should be accounted for in the uncertainty estimation. We propose a new method for estimating uncertainties in such cases. The method goes through all possible scenarios of deviations using Monte Carlo analysis. Varying spectral error functions are produced by combining spectral base functions, and the distorted spectra are used to calculate the colorimetric quantities. Standard deviations of the colorimetric quantities at different scenarios give uncertainties assuming no correlations, uncertainties assuming full correlation, and uncertainties for an unfavorable case of unknown correlations, which turn out to be a significant source of uncertainty. With 1% standard uncertainty in spectral irradiance, the expanded uncertainty of the correlated color temperature of a source corresponding to the CIE Standard Illuminant A may reach as high as 37.2 K in unfavorable conditions, when calculations assuming full correlation give zero uncertainty, and calculations assuming no correlations yield the expanded uncertainties of 5.6 K and 12.1 K, with wavelength steps of 1 nm and 5 nm used in spectral integrations, respectively. We also show that there is an absolute limit of 60.2 K in the error of the correlated color temperature for Standard Illuminant A when assuming 1% standard uncertainty in the spectral irradiance. A comparison of our uncorrelated uncertainties with those obtained using analytical methods by other research groups shows good agreement. We re-estimated the uncertainties for the colorimetric properties of our 1 kW photometric standard lamps using the new method. The revised uncertainty of color temperature is a factor of 2.5 higher than the uncertainty assuming no correlations.

  17. A Smartphone-Based Automatic Measurement Method for Colorimetric pH Detection Using a Color Adaptation Algorithm.

    Science.gov (United States)

    Kim, Sung Deuk; Koo, Youngmi; Yun, Yeoheung

    2017-07-10

    This paper proposes a smartphone-based colorimetric pH detection method using a color adaptation algorithm for point-of-care applications. Although a smartphone camera can be utilized to measure the color information of colorimetric sensors, ambient light changes and unknown built-in automatic image correction operations make it difficult to obtain stable color information. This paper utilizes a 3D printed mini light box and performs a calibration procedure with a paper-printed comparison chart and a reference image which overcomes the drawbacks of smartphone cameras and the difficulty in preparing for the calibration procedure. The color adaptation is performed in the CIE 1976 u'v' color space by using the reference paper in order to stabilize the color variations. Non-rigid u'v' curve interpolation is used to produce the high-resolution pH estimate. The final pH value is estimated by using the best-matching method to handle the nonlinear curve properties of multiple color patches. The experimental results obtained using a pH indicator paper show that the proposed algorithm provides reasonably good estimation of pH detection. With paper-printed accurate color comparison charts and smart color adaptation techniques, superior estimation is achieved in the smartphone-based colorimetric pH detection system for point-of-care application.

  18. Determination Total Phosphour of Maize Plant Samples by Continuous Flow Analyzer in Comparison with Vanadium Molybdate Yellow Colorimetric Method

    OpenAIRE

    LIU Yun-xia; WEN Yun-jie; HUANG Jin-li; LI Gui-hua; CHAI Xiao; WANG Hong

    2015-01-01

    The vanadium molybdate yellow colorimetric method(VMYC method) is regarded as one of conventional methods for determining total phosphorus(P) in plants, but it is time consuming procedure. Continuous flow analyzer(CFA) is a fluid stream segmentation technique with air segments. It is used to measure P concentration based on the molybdate-antimony-ascorbic acid method of Murphy and Riley. Sixty nine of maize plant samples were selected and digested with H2SO4-H2O2. P concentrations in the dige...

  19. Improved Colorimetric Determination of Reserpine in Tablets Using ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, rapid and improved colorimetric method for the assay of reserpine in tablets. Method: The method is based on the aromatic ring coupling of reserpine with 4-carboxyl-2,6-dinitrobenzene diazonium ion with the consequent formation of an azo adduct. Optimization of reaction conditions and ...

  20. Novel methods for improving rapid paper-based protein assays with gold nanoparticle detection

    OpenAIRE

    Lama, Lara

    2017-01-01

    This thesis describes methods for improving sensitivity in rapid singleplex and multiplex microarray assays. The assays utilize the optical characteristics of colloidal gold nanoparticles for the colorimetric detection of proteins. Multiplexed detection in sandwich immunoassays is limited by cross-reactivity between different detection antibodies. The cross-reactivity between antibodies can contribute to increased background noise - decreasing the Limit-of-Detection of the assay - or generate...

  1. Colorimetric micro-assay for accelerated screening of mould inhibitors

    Science.gov (United States)

    Carol A. Clausen; Vina W. Yang

    2013-01-01

    Since current standard laboratory methods are time-consuming macro-assays that rely on subjective visual ratings of mould growth, rapid and quantitative laboratory methods are needed to screen potential mould inhibitors for use in and on cellulose-based products. A colorimetric micro-assay has been developed that uses XTT tetrazolium salt to enzymatically assess...

  2. Accelerated Colorimetric Micro-assay for Screening Mold Inhibitors

    Science.gov (United States)

    Carol A. Clausen; Vina W. Yang

    2014-01-01

    Rapid quantitative laboratory test methods are needed to screen potential antifungal agents. Existing laboratory test methods are relatively time consuming, may require specialized test equipment and rely on subjective visual ratings. A quantitative, colorimetric micro-assay has been developed that uses XTT tetrazolium salt to metabolically assess mold spore...

  3. Selective colorimetric sensors based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction for a simple and rapid determination of mercury

    Science.gov (United States)

    Jarujamrus, Purim; Amatatongchai, Maliwan; Thima, Araya; Khongrangdee, Thatsanee; Mongkontong, Chakrit

    2015-05-01

    In this work, selective colorimetric sensors for simple and rapid detection of Hg(II) ions based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction were developed. The average diameter of synthesized AgNPs was 8.3 ± 1.4 nm which was characterized by transmission electron microscopy (TEM). The abrupt change in absorbance of the unmodified AgNPs was observed which progressively decreased and slightly shifted to the blue wavelength as the concentration of Hg(II) increased, indicating the oxidation of Ag(0) to Ag(I) occurred. It appears that the AgNPs were oxidized by Hg(II), resulting in disintegration of the AgNPs into smaller particles as well as mediating the reduction of Hg(II) to Hg(0) adsorbed onto the surface of AgNPs. The adsorption of Hg(0) resulted in the lack of sufficient charges on AgNPs surfaces due to the decrease in the surface coverage of negatively charged citrate molecules, which then leaded to enlargement of AgNPs. The calibration curve of this technique was demonstrated from 0.5 to 7 ppm (r2 = 0.995), the limit of detection (LOD) was 0.06 ppm (SDblank/slope of calibration curve) with the precision (RSD, n = 4) of 3.24-4.53. Interestingly, the results show a significant enhance in the Hg(II) analytical sensitivity when Cu(II) is doped onto the unmodified AgNPs, which improves the quantitative detection limit to 0.008 ppm. In addition, greater selectivity toward Hg(II) compared with the other metal ions tested was observed. Furthermore, the percentage recoveries of spiked drinking water, tap water and SRM1641d (mercury in water) were in acceptable range with a good precision (RSD) which were in agreement with the values obtained from graphite furnace atomic absorption spectrometer (GFAAS). The technique proposed in this study provides a rapid, simple, sensitive and selective detection method for Hg(II) in water samples.

  4. BIOORGANIC CONCEPTS INVOLVED IN THE DETERMINATION OF GLUCOSE, CHOLESTEROL AND TRIGLYCERIDES IN PLASMA USING THE ENZYMATIC COLORIMETRIC METHOD

    Directory of Open Access Journals (Sweden)

    Fabrício G. Menezes

    2015-05-01

    Full Text Available Bioorganic and biological chemistry have been found to be highly motivating to undergraduate students and in this context, biochemical blood parameter analysis emerges as highly attractive content. In this proposal, several aspects related to analyses of glucose, cholesterol and triglycerides using the enzymatic colorimetric method were involved, and the findings have at least two relevant implications: i introducing students to connections between organic chemistry and biology based on enzymatic processes, including reactivity and mechanistic aspects; ii performing a micro scale bioassay analysis. The proposal requires two theoretical classes (2 h per class and one practical class (4 h.

  5. Colorimetric determination of ferrous-ferric ratio in glass

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, E W

    1987-02-20

    This memorandum describes a simple, rapid colorimetric procedure that can be used for analysis of vitrified melter feed. This method can replace the Moessbauer spectroscopy method for routine DWPF process control analysis. A colorimetric method has been developed that is recommended as a replacement for Moessbauer spectroscopy for process control measurements of the Fe(II)/Fe(III) ratio of melter feed for the DWPF analytical laboratory. The results agree satisfactorily with Moessbauer values. The method is suitable for remote operation and has several advantages. The total time involved is less than 30 minutes. Quantitative measurements of samples, reagents, and dilutions are unnecessary because only the ratio value is required and both Fe(II) and total Fe are measured on the same solution. Small samples (<3 mg total Fe) are required, minimizing radiation exposure, because of the high sensitivity of the colorimetric method. Relative precision and relative accuracy are about {plus minus}5%.

  6. Microfluidic Integration of a Cloth-Based Hybridization Array System (CHAS) for Rapid, Colorimetric Detection of Enterohemorrhagic Escherichia coli (EHEC) Using an Articulated, Centrifugal Platform.

    Science.gov (United States)

    Geissler, Matthias; Clime, Liviu; Hoa, Xuyen D; Morton, Keith J; Hébert, Harold; Poncelet, Lucas; Mounier, Maxence; Deschênes, Mylène; Gauthier, Martine E; Huszczynski, George; Corneau, Nathalie; Blais, Burton W; Veres, Teodor

    2015-10-20

    We describe the translation of a cloth-based hybridization array system (CHAS), a colorimetric DNA detection method that is used by food inspection laboratories for colony screening of pathogenic agents, onto a microfluidic chip format. We also introduce an articulated centrifugal platform with a novel fluid manipulation concept based on changes in the orientation of the chip with respect to the centrifugal force field to time the passage of multiple components required for the process. The platform features two movable and motorized carriers that can be reoriented on demand between 0 and 360° during stage rotation. Articulation of the chip can be used to trigger on-the-fly fluid dispensing through independently addressable siphon structures or to relocate solutions against the centrifugal force field, making them newly accessible for downstream transfer. With the microfluidic CHAS, we achieved significant reduction in the size of the cloth substrate as well as the volume of reagents and wash solutions. Both the chip design and the operational protocol were optimized to perform the entire process in a reliable, fully automated fashion. A demonstration with PCR-amplified genomic DNA confirms on-chip detection and identification of Escherichia coli O157:H7 from colony isolates in a colorimetric multiplex assay using rfbO157, fliCH7, vt1, and vt2 genes.

  7. A rapid molecular diagnosis of cutaneous leishmaniasis by colorimetric malachite green-loop-mediated isothermal amplification (LAMP) combined with an FTA card as a direct sampling tool.

    Science.gov (United States)

    Nzelu, Chukwunonso O; Cáceres, Abraham G; Guerrero-Quincho, Silvia; Tineo-Villafuerte, Edwin; Rodriquez-Delfin, Luis; Mimori, Tatsuyuki; Uezato, Hiroshi; Katakura, Ken; Gomez, Eduardo A; Guevara, Angel G; Hashiguchi, Yoshihisa; Kato, Hirotomo

    2016-01-01

    Leishmaniasis remains one of the world's most neglected diseases, and early detection of the infectious agent, especially in developing countries, will require a simple and rapid test. In this study, we established a quick, one-step, single-tube, highly sensitive loop-mediated isothermal amplification (LAMP) assay for rapid detection of Leishmania DNA from tissue materials spotted on an FTA card. An FTA-LAMP with pre-added malachite green was performed at 64°C for 60min using a heating block and/or water bath and DNA amplification was detected immediately after incubation. The LAMP assay had high detection sensitivity down to a level of 0.01 parasites per μl. The field- and clinic-applicability of the colorimetric FTA-LAMP assay was demonstrated with 122 clinical samples collected from patients suspected of having cutaneous leishmaniasis in Peru, from which 71 positives were detected. The LAMP assay in combination with an FTA card described here is rapid and sensitive, as well as simple to perform, and has great potential usefulness for diagnosis and surveillance of leishmaniasis in endemic areas. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. A micro-plate colorimetric assay for rapid determination of trace zinc in animal feed, pet food and drinking water by ion masking and statistical partitioning correction.

    Science.gov (United States)

    Wang, Jiayi; Niu, Yiming; Zhang, Chi; Chen, Yiqiang

    2018-04-15

    A new micro-plate colorimetric assay was developed for rapid determination of zinc in animal feed, pet food and drinking water. Zinc ion was extracted from sample by trichloroacetic acid and then reacted with 2-(5-Bromo-2-pyridylazo)-5-[N-propyl-N-(3-sulfopropyl)amino]phenol (5-Br-PAPS) to form a Zn-PAPS complex to be detected by a micro-plate reader at 552 nm. An ion masking formula including salicylaldoxime, deferoxamine and sodium citrate were screened and applied to exclude the interference from other heavy metals and a partitioning correction approach was proposed to eliminate the matrix effect derived from feed sample. The entire procedure can be completed within 40 min and the detection range was 0.038-8.0 μg mL-1 zinc in buffer solution. Moreover, the analysis in real samples revealed the consistency of results by this assay and those by atomic absorption spectrometry analysis. These features highlighted the possibility for this proposed assay to be used for rapid determination of zinc in complex samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Comparing different methods for fast screening of microbiological quality of beach sand aimed at rapid-response remediation.

    Science.gov (United States)

    Testolin, Renan C; Almeida, Tito C M; Polette, Marcus; Branco, Joaquim O; Fischer, Larissa L; Niero, Guilherme; Poyer-Radetski, Gabriel; Silva, Valéria C; Somensi, Cleder A; Corrêa, Albertina X R; Corrêa, Rogério; Rörig, Leonardo R; Itokazu, Ana Gabriela; Férard, Jean-François; Cotelle, Sylvie; Radetski, Claudemir M

    2017-05-15

    There is scientific evidence that beach sands are a significant contributor to the pathogen load to which visitors are exposed. To develop beach quality guidelines all beach zones must be included in microbiological evaluations, but monitoring methods for beach sand quality are relatively longstanding, expensive, laborious and require moderate laboratory infrastructure. This paper aimed to evaluate the microorganism activity in different beach zones applying and comparing a classical method of membrane filtration (MF) with two colorimetric screening methods based on fluorescein (FDA) and tetrazolium (TTC) salt biotransformation to evaluate a new rapid and low-cost method for beach sand microbiological contamination assessments. The colorimetric results can help beach managers to evaluate rapidly and at low cost the microbiological quality of different beach zones in order to decide whether remedial actions need to be adopted to prevent exposure of the public to microbes due to beach sand and/or water contamination. Copyright © 2017. Published by Elsevier Ltd.

  10. In vitro colorimetric evaluation of the efficacy of various bleaching methods and products.

    Science.gov (United States)

    Dietschi, Didier; Rossier, Sandrine; Krejci, Ivo

    2006-01-01

    Various bleaching modalities are now offered to patients, either monitored by the dental office or self-directed, for which relative efficacy is unknown. The aim of this in vitro study was to evaluate the ability of different bleaching products and protocols to lighten enamel and dentin. Bovine tooth samples of standardized thickness (2.5 +/- 0.025 mm with similar dentin and enamel thicknesses) were prepared and stained with whole blood and hemolysate before being submitted to 11 different bleaching regimens: home bleaching using 10%, 15%, 16%, or 20% carbamide peroxide, power bleaching using 15% hydrogen peroxide, 30% hydrogen peroxide, or 25% carbamide peroxide with or without light activation, and over-the-counter bleaching strips containing 5.3% hydrogen peroxide. Colorimetric measurements were performed on each sample side, according to the CIE L*a*b* system, before and after staining as well as after each series of 5 bleaching sessions (number of applications varied from 5 to 20 times, according to the bleaching protocol). All products and protocols produced a similar bleaching effect on enamel, while the home bleaching regimen proved largely superior to lighten dentin. In-office bleaching techniques proved less efficient than home bleaching for removing stains deposited in dentin.

  11. Colorimetric detection for paper-based biosensing applications

    Science.gov (United States)

    Brink, C.; Joubert, T.-H.

    2016-02-01

    Research on affordable point-of-care health diagnostics is rapidly advancing1. Colorimetric biosensor applications are typically qualitative, but recently the focus has been shifted to quantitative measurements2,3. Although numerous qualitative point-of-care (POC) health diagnostic devices are available, the challenge exists of developing a quantitative colorimetric array reader system that complies with the ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, Deliverable to end-users) principles of the World Health Organization4. This paper presents a battery powered 8-bit tonal resolution colorimetric sensor circuit for paper microfluidic assays using low cost photo-detection circuitry and a low-power LED light source. A colorimetric 3×3-pixel array reader was developed for rural environments where resources and personnel are limited. The device sports an ultralow-power E-ink paper display. The colorimetric device includes integrated GPS functionality and EEPROM memory to log measurements with geo-tags for possible analysis of regional trends. The device competes with colour intensity measurement techniques using smartphone cameras, but proves to be a cheaper solution, compensating for the typical performance variations between cameras of different brands of smartphones. Inexpensive methods for quantifying bacterial assays have been shown using desktop scanners, which are not portable, and cameras, which suffer severely from changes in ambient light in different environments. Promising colorimetric detection results have been demonstrated using devices such as video cameras5, digital colour analysers6, flatbed scanners7 or custom portable readers8. The major drawback of most of these methods is the need for specialized instrumentation and for image analysis on a computer.

  12. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.

    2006-01-01

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  13. Integration of Nanoparticle-Based Paper Sensors into the Classroom: An Example of Application for Rapid Colorimetric Analysis of Antioxidants

    Science.gov (United States)

    Sharpe, Erica; Andreescu, Silvana

    2015-01-01

    We describe a laboratory experiment that employs the Nanoceria Reducing Antioxidant Capacity (or NanoCerac) Assay to introduce students to portable nanoparticle-based paper sensors for rapid analysis and field detection of polyphenol antioxidants. The experiment gives students a hands-on opportunity to utilize nanoparticle chemistry to develop…

  14. Colorimetric method for the detection of melamine using in-situ formed silver nanoparticles via tannic acid

    Science.gov (United States)

    Alam, Md. Fazle; Laskar, Amaj Ahmed; Ahmed, Shahbaz; Shaida, Mohd. Azfar; Younus, Hina

    2017-08-01

    Melamine toxicity has recently attracted worldwide attention as it causes renal failure and the death of humans and animals. Therefore, developing a simple, fast and sensitive method for the routine detection of melamine is the need of the hour. Herein, we have developed a selective colorimetric method for the detection of melamine in milk samples based upon in-situ formation of silver nanoparticles (AgNPs) via tannic acid. The AgNPs thus formed were characterized by UV-Visible spectrophotometer, transmission electron microscope (TEM), zetasizer and dynamic light scattering (DLS). The AgNPs were used to detect melamine under in vitro condition and in raw milk spiked with melamine. Under optimal conditions, melamine could be selectively detected in vitro within the concentration range of 0.05-1.4 μM with a limit of detection (LOD) of 0.01 μM, which is lower than the strictest melamine safety requirement of 1 ppm. In spiked raw milk, the recovery percentage range was 99.5-106.5% for liquid milk and 98.5-105.5% for powdered milk. The present method shows extreme selectivity with no significant interference with other substances like urea, glucose, glycine, ascorbic acid etc. This assay method does not utilize organic cosolvents, enzymatic reactions, light sensitive dye molecules and sophisticated instrumentation, thereby overcoming some of the limitations of the other conventional methods.

  15. Optimization of the reactional medium and a food impact study for a colorimetric in situ Salmonella spp. detection method.

    Science.gov (United States)

    Junillon, Thomas; Mosticon, David; Mallen, Benoît; Baril, Florent; Morand, Lucie; Michel, Déborah; Flandrois, Jean-Pierre

    2014-07-02

    Foodborne pathogens are still a major concern for public health authorities. In this paper, we describe the optimization of a previously reported method which combines a highly specific capture of targeted food pathogens with an intracellular staining method. The reaction medium was optimized to simultaneously allow specific enrichment of Salmonella and maximize the staining of the target pathogen. This in situ colorimetric concept was evaluated with a broad range of food samples artificially contaminated with low levels of stressed Salmonella to mimic natural contamination conditions. This direct detection method compared favorably to a commercially available immunoassay system (Vidas® UP Salmonella), for cooked meat, dry milk powder and egg products. Globally 88% agreement was obtained between the two methods with a sensitivity of 80% and a specificity of 100% for the tested method. Main discordances were obtained with food matrices having high levels of competitive Gram negative microflora. These observations show that the design of an adapted culture medium is necessary to enhance the specific in situ capture and revelation system. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Innovative rapid construction/reconstruction methods.

    Science.gov (United States)

    2005-07-01

    Innovative construction and reconstruction methods provide the opportunity to significantly reduce the time of roadway projects while maintaining the necessary quality of workmanship. The need for these rapid methods stems from the increase in ...

  17. Paper-based magnetic nanoparticle-peptide probe for rapid and quantitative colorimetric detection of Escherichia coli O157:H7.

    Science.gov (United States)

    Suaifan, Ghadeer A R Y; Alhogail, Sahar; Zourob, Mohammed

    2017-06-15

    There is a critical and urgent demand for a simple, rapid and specific qualitative and quantitative colorimetric biosensor for the detection of the food contaminant Escherichia coli O157:H7 (E. coli O157:H7) in complex food products due to the recent outbreaks of food-borne diseases. Traditional detection techniques are time-consuming, require expensive instrumentation and are labour-intensive. To overcome these limitations, a novel, ultra-rapid visual biosensor was developed based on the ability of E. coli O157:H7 proteases to change the optical response of a surface-modified, magnetic nanoparticle-specific (MNP-specific) peptide probe. Upon proteolysis, a gradual increase in the golden color of the sensor surface was visually observed. The intensification of color was correlated with the E. coli O157:H7 concentration. The color change resulting from the dissociation of the self-assembled monolayer (SAM) was detected by the naked eye and analysed using an image analysis software (ImageJ) for the purpose of quantitative detection. This biosensor demonstrated high sensitivity and applicability, with lower limits of detection of 12CFUmL -1 in broth samples and 30-300CFUmL -1 in spiked complex food matrices. In conclusion, this approach permits the use of a disposable biosensor chip that can be mass-produced at low cost and can be used not only by food manufacturers but also by regulatory agencies for better control of potential health risks associated with the consumption of contaminated foods. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Colorimetric-Solid Phase Extraction Technology for Water Quality Monitoring: Evaluation of C-SPE and Debubbling Methods in Microgravity

    Science.gov (United States)

    Hazen-Bosveld, April; Lipert, Robert J.; Nordling, John; Shih, Chien-Ju; Siperko, Lorraine; Porter, Marc D.; Gazda, Daniel B.; Rutz, Jeff A.; Straub, John E.; Schultz, John R.; hide

    2007-01-01

    Colorimetric-solid phase extraction (C-SPE) is being developed as a method for in-flight monitoring of spacecraft water quality. C-SPE is based on measuring the change in the diffuse reflectance spectrum of indicator disks following exposure to a water sample. Previous microgravity testing has shown that air bubbles suspended in water samples can cause uncertainty in the volume of liquid passed through the disks, leading to errors in the determination of water quality parameter concentrations. We report here the results of a recent series of C-9 microgravity experiments designed to evaluate manual manipulation as a means to collect bubble-free water samples of specified volumes from water sample bags containing up to 47% air. The effectiveness of manual manipulation was verified by comparing the results from C-SPE analyses of silver(I) and iodine performed in-flight using samples collected and debubbled in microgravity to those performed on-ground using bubble-free samples. The ground and flight results showed excellent agreement, demonstrating that manual manipulation is an effective means for collecting bubble-free water samples in microgravity.

  19. A new method for rapid Canine retraction

    Directory of Open Access Journals (Sweden)

    "Khavari A

    2001-06-01

    Full Text Available Distraction osteogenesis method (Do in bone lengthening and rapid midpalatal expansion have shown the great ability of osteognic tissues for rapid bone formation under distraction force and special protocol with optimum rate of one millimeter per day. Periodontal membrane of teeth (PDM is the extension of periostium in the alveolar socked. Orthodontic force distracts PDM fibers in the tension side and then bone formation will begin.Objects: Rapid retraction of canine tooth into extraction space of first premolar by DO protocol in order to show the ability of the PDM in rapid bone formation. The other objective was reducing total orthodontic treatment time of extraction cases.Patients and Methods: Tweleve maxillary canines in six patients were retracted rapidly in three weeks by a custom-made tooth-born appliance. Radiographic records were taken to evaluate the effects of heavy applied force on canine and anchorage teeth.Results: Average retraction was 7.05 mm in three weeks (2.35 mm/week. Canines rotated distal- in by mean 3.5 degrees.Anchorage loss was from 0 to 0.8 mm with average of 0.3 mm.Root resorption of canines was negligible, and was not significant clinically. Periodontium was normal after rapid retraction. No hazard for pulp vitality was observed.Discussion: PDM responded well to heavy distraction force by Do protocol. Rapid canine retraction seems to be a safe method and can considerabely reduce orthodontic time.

  20. Simple Extractive Colorimetric Determination of Oxaprozin by Acid-Dye Complexation Methods in Solid Dosage Form

    Directory of Open Access Journals (Sweden)

    M. Ganesh

    2008-01-01

    Full Text Available A simple and sensitive extractive spectrophometric method has been described for the assay of oxaprozin (OXA either in pure form or in pharmaceutical solid dosage form. The developed method involves formation of colored chloroform extractable ion-pair complex of OXA with bromocresol green in aqueous acidic medium. The extracted complexes showed absorbance maxima at 421 nm. Beer's law is obeyed in the concentration range of 10-50 μg mL-1. This method has been applied to the determination of drug in commercial tablets. Results of analysis were validated statistically. The excipients present in the formulations do not interfere with the assay procedure.

  1. Tentative test method for lead in the atmosphere by colorimetric dithizone procedure

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    This method covers the determination of low levels of atmospheric lead. It involves separate measurements of particulate lead and vaporous lead. For the purpose of this method particulate lead is that collected on an efficient filter. Vaporous lead is that which will pass through a 0.45-..mu..m membrane filter or its equivalent and includes various tetra alkyl lead compounds or their partially decomposed products, or both.

  2. A scoping review of rapid review methods.

    Science.gov (United States)

    Tricco, Andrea C; Antony, Jesmin; Zarin, Wasifa; Strifler, Lisa; Ghassemi, Marco; Ivory, John; Perrier, Laure; Hutton, Brian; Moher, David; Straus, Sharon E

    2015-09-16

    Rapid reviews are a form of knowledge synthesis in which components of the systematic review process are simplified or omitted to produce information in a timely manner. Although numerous centers are conducting rapid reviews internationally, few studies have examined the methodological characteristics of rapid reviews. We aimed to examine articles, books, and reports that evaluated, compared, used or described rapid reviews or methods through a scoping review. MEDLINE, EMBASE, the Cochrane Library, internet websites of rapid review producers, and reference lists were searched to identify articles for inclusion. Two reviewers independently screened literature search results and abstracted data from included studies. Descriptive analysis was conducted. We included 100 articles plus one companion report that were published between 1997 and 2013. The studies were categorized as 84 application papers, seven development papers, six impact papers, and four comparison papers (one was included in two categories). The rapid reviews were conducted between 1 and 12 months, predominantly in Europe (58 %) and North America (20 %). The included studies failed to report 6 % to 73 % of the specific systematic review steps examined. Fifty unique rapid review methods were identified; 16 methods occurred more than once. Streamlined methods that were used in the 82 rapid reviews included limiting the literature search to published literature (24 %) or one database (2 %), limiting inclusion criteria by date (68 %) or language (49 %), having one person screen and another verify or screen excluded studies (6 %), having one person abstract data and another verify (23 %), not conducting risk of bias/quality appraisal (7 %) or having only one reviewer conduct the quality appraisal (7 %), and presenting results as a narrative summary (78 %). Four case studies were identified that compared the results of rapid reviews to systematic reviews. Three studies found that the conclusions between

  3. Simple extractive colorimetric determination of levofloxacin by acid-dye complexation methods in pharmaceutical preparations.

    Science.gov (United States)

    Ashour, Safwan; Al-Khalil, Raghad

    2005-09-01

    Two simple and sensitive extractive spectrophotometric methods have been described for the assay of levofloxacin (LVFX) either in pure form or in pharmaceutical formulations. The developed methods involve formation of colored chloroform extractable ion-pair complexes (1:1 and 1:2 drug/dye) of levofloxacin with bromophenol blue (BPB) and bromocresol green (BCG) in aqueous acidic medium. The extracted complexes showed absorbance maxima at 424 and 428 nm for LVFX-BPB and LVFX-BCG, respectively. Beer's law is obeyed in the concentration ranges 1.85-31.5 and 1.85-25 microg ml(-1) with BPB and BCG, respectively. The methods have been applied to the determination of drug in commercial tablets. Results of analysis were validated statistically. The excipients present in the formulations do not interfere with the assay procedure.

  4. Photometric and Colorimetric Assessment of LED Chip Scale Packages by Using a Step-Stress Accelerated Degradation Test (SSADT) Method.

    Science.gov (United States)

    Qian, Cheng; Fan, Jiajie; Fang, Jiayi; Yu, Chaohua; Ren, Yi; Fan, Xuejun; Zhang, Guoqi

    2017-10-16

    By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in LEDs, the thermal, photometric, and colorimetric properties of two types of LED chip scale packages (CSPs), i.e., 4000 °K and 5000 °K samples each of which was driven by two different levels of currents (i.e., 120 mA and 350 mA, respectively), were investigated under an increasing temperature from 55 °C to 150 °C and a systemic study of driving current effect on the SSADT results were also reported in this paper. During SSADT, junction temperatures of the test samples have a positive relationship with their driving currents. However, the temperature-voltage curve, which represents the thermal resistance property of the test samples, does not show significant variance as long as the driving current is no more than the sample's rated current. But when the test sample is tested under an overdrive current, its temperature-voltage curve is observed as obviously shifted to the left when compared to that before SSADT. Similar overdrive current affected the degradation scenario is also found in the attenuation of Spectral Power Distributions (SPDs) of the test samples. As used in the reliability qualification, SSADT provides explicit scenes on color shift and correlated color temperature (CCT) depreciation of the test samples, but not on lumen maintenance depreciation. It is also proved that the varying rates of the color shift and CCT depreciation failures can be effectively accelerated with an increase of the driving current, for instance, from 120 mA to 350 mA. For these reasons, SSADT is considered as a suitable accelerated test method for qualifying these two failure modes of LED CSPs.

  5. A Low-Cost Imaging Method for the Temporal and Spatial Colorimetric Detection of Free Amines on Maize Root Surfaces

    Directory of Open Access Journals (Sweden)

    Truc H. Doan

    2017-08-01

    Full Text Available Plant root exudates are important mediators in the interactions that occur between plants and microorganisms in the soil, yet much remains to be learned about spatial and temporal variation in their production. This work outlines a method utilizing a novel colorimetric paper to detect spatial and temporal changes in the production of nitrogen-containing compounds on the root surface. While existing methods have made it possible to conduct detailed analysis of root exudate composition, relatively less is known about where in the root system exudates are produced and how this localization changes as the root grows. Furthermore, there is much to learn about how exudate localization and composition varies in response to stress. Root exudates are chemically diverse secretions composed of organic acids, amino acids, proteins, sugars, and other metabolites. The sensor utilized for the method, ninhydrin, is a colorless substance in solution that reacts with free amino groups to form a purple dye. A detection paper was developed by formulating ninhydrin into a print solution that was uniformly deposited onto paper with a commercial ink jet printer. This “ninhydrin paper” was used to analyze the chemical makeup of root surfaces from maize seedlings grown vertically on germination paper. Through contact between the ninhydrin paper and seedling root surfaces, combined with images of both the seedlings and dried ninhydrin papers captured using a standard flatbed scanner, nitrogen-containing substances on the root surface can be localized and concentration of signal estimated for over 2 weeks of development. The method was found to be non-inhibiting to plant growth over the analysis period although damage to root hairs was observed. The method is sensitive in the detection of free amines at concentrations as little as 140 μM. Furthermore, ninhydrin paper is stable, showing consistent color changes up to 2 weeks after printing. This relatively simple, low

  6. Proteus mirabilis biofilm - Qualitative and quantitative colorimetric methods-based evaluation

    Directory of Open Access Journals (Sweden)

    Joanna Kwiecinska-Piróg

    2014-12-01

    Full Text Available Proteus mirabilis strains ability to form biofilm is a current topic of a number of research worldwide. In this study the biofilm formation of P. mirabilis strains derived from urine of the catheterized and non-catheterized patients has been investigated. A total number of 39 P. mirabilis strains isolated from the urine samples of the patients of dr Antoni Jurasz University Hospital No. 1 in Bydgoszcz clinics between 2011 and 2012 was used. Biofilm formation was evaluated using two independent quantitative and qualitative methods with TTC (2,3,5-triphenyl-tetrazolium chloride and CV (crystal violet application. The obtained results confirmed biofilm formation by all the examined strains, except quantitative method with TTC, in which 7.7% of the strains did not have this ability. It was shown that P. mirabilis rods have the ability to form biofilm on the surfaces of both biomaterials applied, polystyrene and polyvinyl chloride (Nelaton catheters. The differences in ability to form biofilm observed between P. mirabilis strains derived from the urine of the catheterized and non-catheterized patients were not statistically significant.

  7. Proteus mirabilis biofilm - qualitative and quantitative colorimetric methods-based evaluation.

    Science.gov (United States)

    Kwiecinska-Piróg, Joanna; Bogiel, Tomasz; Skowron, Krzysztof; Wieckowska, Ewa; Gospodarek, Eugenia

    2014-01-01

    Proteus mirabilis strains ability to form biofilm is a current topic of a number of research worldwide. In this study the biofilm formation of P. mirabilis strains derived from urine of the catheterized and non-catheterized patients has been investigated. A total number of 39 P. mirabilis strains isolated from the urine samples of the patients of dr Antoni Jurasz University Hospital No. 1 in Bydgoszcz clinics between 2011 and 2012 was used. Biofilm formation was evaluated using two independent quantitative and qualitative methods with TTC (2,3,5-triphenyl-tetrazolium chloride) and CV (crystal violet) application. The obtained results confirmed biofilm formation by all the examined strains, except quantitative method with TTC, in which 7.7% of the strains did not have this ability. It was shown that P. mirabilis rods have the ability to form biofilm on the surfaces of both biomaterials applied, polystyrene and polyvinyl chloride (Nelaton catheters). The differences in ability to form biofilm observed between P. mirabilis strains derived from the urine of the catheterized and non-catheterized patients were not statistically significant.

  8. A colorimetric competitive displacement assay for the evaluation of catalytic peptides.

    Science.gov (United States)

    Gest, Anneliese M M; Aguiluz, Erika M; Mays, Malik T; Liu, Xinyu; Neidhart, Eliza K; Witus, Leah S

    2017-12-13

    An indicator displacement assay has been adapted to detect the diol products of the aldol reaction between 4-nitrobenzaldehyde and hydroxyacetone in crude reaction mixtures. This provides a rapid colorimetric method of detecting product formation and thus evaluating potential catalysts, which is demonstrated using multiple catalytic peptides.

  9. Photometric and Colorimetric Assessment of LED Chip Scale Packages by Using a Step-Stress Accelerated Degradation Test (SSADT Method

    Directory of Open Access Journals (Sweden)

    Cheng Qian

    2017-10-01

    Full Text Available By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT in LEDs, the thermal, photometric, and colorimetric properties of two types of LED chip scale packages (CSPs, i.e., 4000 °K and 5000 °K samples each of which was driven by two different levels of currents (i.e., 120 mA and 350 mA, respectively, were investigated under an increasing temperature from 55 °C to 150 °C and a systemic study of driving current effect on the SSADT results were also reported in this paper. During SSADT, junction temperatures of the test samples have a positive relationship with their driving currents. However, the temperature-voltage curve, which represents the thermal resistance property of the test samples, does not show significant variance as long as the driving current is no more than the sample’s rated current. But when the test sample is tested under an overdrive current, its temperature-voltage curve is observed as obviously shifted to the left when compared to that before SSADT. Similar overdrive current affected the degradation scenario is also found in the attenuation of Spectral Power Distributions (SPDs of the test samples. As used in the reliability qualification, SSADT provides explicit scenes on color shift and correlated color temperature (CCT depreciation of the test samples, but not on lumen maintenance depreciation. It is also proved that the varying rates of the color shift and CCT depreciation failures can be effectively accelerated with an increase of the driving current, for instance, from 120 mA to 350 mA. For these reasons, SSADT is considered as a suitable accelerated test method for qualifying these two failure modes of LED CSPs.

  10. Comparison of serum copper determination by colorimetric and atomic absorption spectrometric methods in seven different laboratories. The S.F.B.C. (Société Française de Biologie Clinique) Trace Element Group.

    Science.gov (United States)

    Arnaud, J; Chappuis, P; Zawislak, R; Houot, O; Jaudon, M C; Bienvenu, F; Bureau, F

    1993-02-01

    An interlaboratory collaborative trial was conducted on the determination of serum copper using two different methods, based on colorimetry (test combination Copper, Boehringer Mannheim, Mannheim, Germany) and flame atomic absorption spectrometry (FAAS). The general performance of the colorimetric method was below that of FAAS, except for sensitivity and linear range, as assessed by detection limit (0.44 versus 1.32 mumol/L) and upper limit of linearity (150 versus 50 mumol/L). The range of the between-run CVs and the recovery of standard additions were, respectively, 2.3-11.9% and 92-127% for the colorimetric method and 1.1-6.0% and 93-101% for the FAAS method. Interferences were minimal with both methods. The two techniques correlated satisfactorily (the correlation coefficients ranged from 0.945-0.970 among laboratories) but the colorimetric assay exhibited slightly higher results than the FAAS method. Each method was transferable among laboratories.

  11. Analytical properties of some commercially available nitrate reductase enzymes evaluated as replacements for cadmium in automated, semiautomated, and manual colorimetric methods for determination of nitrate plus nitrite in water

    Science.gov (United States)

    Patton, Charles J.; Kryskalla, Jennifer R.

    2013-01-01

    -water and groundwater samples that were analyzed in parallel by CFA-CdR and CFA enzyme-reduction methods. Finally, (3) demonstration of a semiautomated batch procedure in which 2-milliliter analyzer cups or disposable spectrophotometer cuvettes serve as reaction vessels for enzymatic reduction of nitrate to nitrite prior to analytical determinations. After the reduction step, analyzer cups are loaded onto CFA, flow injection, or discrete analyzers for simple, rapid, automatic nitrite determinations. In the case of manual determinations, analysts dispense colorimetric reagents into cuvettes containing post-reduction samples, allow time for color to develop, insert cuvettes individually into a spectrophotometer, and record percent transmittance or absorbance in relation to a reagent blank. Data presented here demonstrate equivalent analytical performance of enzymatic reduction NOx methods in these various formats to that of benchmark CFA-CdR NOx methods.

  12. Determination of dietary starch in animal feeds and pet food by an enzymatic-colorimetric method: collaborative study.

    Science.gov (United States)

    Hall, Mary Beth

    2015-01-01

    Starch, glycogen, maltooligosaccharides, and other α-1,4- and α-1,6-linked glucose carbohydrates, exclusive of resistant starch, are collectively termed "dietary starch". This nutritionally important fraction is increasingly measured for use in diet formulation for animals as it can have positive or negative effects on animal performance and health by affecting energy supply, glycemic index, and formation of fermentation products by gut microbes. AOAC Method 920.40 that was used for measuring dietary starch in animal feeds was invalidated due to discontinued production of a required enzyme. As a replacement, an enzymatic-colorimetric starch assay developed in 1997 that had advantages in ease of sample handling and accuracy compared to other methods was considered. The assay was further modified to improve utilization of laboratory resources and reduce time required for the assay. The assay is quasi-empirical: glucose is the analyte detected, but its release is determined by run conditions and specification of enzymes. The modified assay was tested in an AOAC collaborative study to evaluate its accuracy and reliability for determination of dietary starch in animal feedstuffs and pet foods. In the assay, samples are incubated in screw cap tubes with thermostable α-amylase in pH 5.0 sodium acetate buffer for 1 h at 100°C with periodic mixing to gelatinize and partially hydrolyze α-glucan. Amyloglucosidase is added, and the reaction mixture is incubated at 50°C for 2 h and mixed once. After subsequent addition of water, mixing, clarification, and dilution as needed, free + enzymatically released glucose are measured. Values from a separate determination of free glucose are subtracted to give values for enzymatically released glucose. Dietary starch equals enzymatically released glucose multiplied by 162/180 (or 0.9) divided by the weight of the as received sample. Fifteen laboratories that represented feed company, regulatory, research, and commercial feed

  13. Rapid determination of total phenols in seawater by 4-aminoantipyrine colorimetry

    Digital Repository Service at National Institute of Oceanography (India)

    Kadam, A.N.; Bhangale, V.P.

    A rapid and efficient 4-aminoantipyrine (4-AAP) colorimetric method without any cleanup step to determine total phenols in seawater is described. Efficiency of the method for seawater using external addition of phenol concentrations with working...

  14. Rapid Column Extraction method for SoilRapid Column Extraction method for Soil

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod, L. III; Culligan, Brian K.

    2005-11-07

    The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu) neptunium (Np), uranium (U), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha spectrometry. The method combines a rapid fusion step for total dissolution to dissolve refractory analytes and matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

  15. Preparation of reversible colorimetric temperature nanosensors and their application in quantitative two-dimensional thermo-imaging.

    Science.gov (United States)

    Wang, Xu-dong; Song, Xin-hong; He, Chun-yan; Yang, Chaoyong James; Chen, Guonan; Chen, Xi

    2011-04-01

    Reversible colorimetric temperature nanosensors were prepared using a very simple precipitation method to encapsulate two color luminescent dyes. These nanosensors presented obvious reversible temperature response and enabled both rapid colorimetric temperature estimation using the eyes and quantitative two-dimensional thermo-imaging. Heat-exchange induced fluid motion was, for the first time, rapidly, precisely, and quantitatively imaged by just taking color pictures, and this presented good temporal and spatial resolution for studying heat-driven hydrodynamics. These nanosensors should have great application in micro/nanoscale research and also fabrication into films for macroscopic study.

  16. Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method.

    Science.gov (United States)

    Song, Dean; Liu, Huijuan; Qiang, Zhimin; Qu, Jiuhui

    2014-05-15

    Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe. A kinetic equation was first derived to estimate the reaction rate constant of DPD towards chlorine under a given pH and temperature condition. Then, on that basis, an SFS competition kinetics method was proposed to determine directly the chlorination rate constants of several representative compounds including tetracycline, ammonia, and four α-amino acids. Although Cl2O is more reactive than HOCl, its contribution to the overall chlorination kinetics of the test compounds could be neglected in this study. Finally, the developed method was validated through comparing the experimentally measured chlorination rate constants of the selected compounds with those obtained or calculated from literature and analyzing with Taft's correlation as well. This study demonstrates that the SFS competition kinetics method can measure the chlorination rate constants of a test compound rapidly and accurately. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. A new colorimetric DPPH• scavenging activity method with no need for a spectrophotometer applied on synthetic and natural antioxidants and medicinal herbs.

    Science.gov (United States)

    Akar, Zeynep; Küçük, Murat; Doğan, Hacer

    2017-12-01

    2,2-Diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging, the most commonly used antioxidant method with more than seventeen thousand articles cited, is very practical; however, as with most assays, it has the major disadvantage of dependence on a spectrophotometer. To overcome this drawback, the colorimetric determination of the antioxidant activity using a scanner and freely available Image J software was developed. In this new method, the mixtures of solutions of DPPH• and standard antioxidants or extracts of common medicinal herbs were dropped onto TLC plates, after an incubation period. The spot images were evaluated with Image J software to determine CSC50 values, the sample concentrations providing 50% colour reduction, which were very similar with the SC50 values obtained with spectrophotometric method. The advantages of the new method are the use of lower amounts of reagents and solvents, no need for costly spectrophotometers, and thus significantly lowered costs, and convenient implementation in any environment and situation.

  18. Estimation of alpha-amino nitrogen in plasma and urine by the colorimetric ninhydrin reaction

    Science.gov (United States)

    Matthews, D. M.; Muir, G. G.; Baron, D. N.

    1964-01-01

    Methods are described for the estimation of plasma and urine α-amino nitrogen by the colorimetric ninhydrin reaction; in the method for urine, both ammonia and urea are separated by a rapid ion-exchange resin procedure. Two methods of estimation are given; one has the advantage of great simplicity, but involves the use of cyanide; in the other, cyanide is eliminated. Normal values are reported; they correspond well with those obtained by the gasometric ninhydrin method. PMID:14149940

  19. Colorimetric pH measurement for seawater samples using a three light-emitting diodes detector and a calibration method for temperature dependence.

    Science.gov (United States)

    Okamura, Kei; Kimoto, Hideshi; Noguchi, Takuroh; Hatta, Mayumi; Kawakami, Hiroaki; Suzue, Takahiko

    2014-01-01

    A colorimetric pH measurement of seawater samples using a light source comprising a three light-emitting diodes (TLED) detector and meta-cresol purple (mCP) as an indicator was investigated. The molar absorption ratios (e1, e2, and e3/e2) for mCP using the TLED detector at 25°C were determined to be 0, 1.9994, and 0.1010, respectively. Next, the pH values of 2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) and 2-aminopyride (AMP) seawater buffers were determined. Notably, the raw pH of TRIS buffer (∼8.1) agreed with the reference value, while that for the AMP buffer (∼6.8) had an error of +0.004 due to the small absorption ratio (R) and being out of the lower adequate pH range (> 7.2) for mCP. pHT measurements obtained for seawater samples using the present colorimetric method agreed with those obtained using a glass electrode. These results demonstrate that this low-cost TLED detection system with a short cell length, 5 cm, can be used for seawater pHT analysis.

  20. Multi-colorimetric sensor array for detection of illegal materials

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Boisen, Anja; Jakobsen, Mogens Havsteen

    2012-01-01

    The detection of low pressure illegal compounds is an important analytical problem which requires reliable, selective and sensitive detection methods which provide the highest level of confidence in the result. Therefore, to contribute in the successful development of the recognition technology...... and signal processing enhancements to sensing methods, recognition ability, data acquisition time and data processing algorithms are necessary. In this research we work towards the development of a rapid, easy in use, highly sensitive, specific (minimal false positives) sensor based on a colorimetric sensing...

  1. A sensitive method for determining total vanadium in water samples using colorimetric-solid-phase extraction-fiber optic reflectance spectroscopy.

    Science.gov (United States)

    Filik, Hayati; Yanaz, Zeynep

    2009-12-30

    A selective colorimetric-solid-phase extraction (C-SPE) method for the determination of total vanadium in water samples was developed. This method introduced a new variation of C-SPE. The colour reaction is based on the reaction of vanadium(V) ternary complex formed with 1-(2-Pyridylazo)-2-naphtol (PAN) in the presence hydrogen peroxide (H(2)O(2)). In this technique, the target analytes in samples are extracted onto solid matrix loaded with a colorimetric reagent and then quantified directly on the adsorbent surface by using a miniature fiber optic reflectance spectrometer. The measurements were carried out at a wavelength of 589.4 nm since it yielded the largest divergence different in reflectance spectra before and after reaction with the vanadium. The overall time required for the C-SPE procedure was approximately 20 min. The amount of concentrated V is then determined in a few seconds by using miniature reflectance spectrometer. At the optimal conditions, a calibration curve was constructed, revealing a linear range of 0.05-0.52 mg L(-1) and a detection limit as low as 0.01 mg L(-1) while the RSD lower than 2.8%. In order to verify the accuracy of the method, a certified reference water samples (TMDA) were analysed and the results obtained were in good agreement with the certified values. The proposed method was applied to the determination of vanadium in tap water, seawater samples with a recovery for the spiked samples in the range of 98-102%.

  2. Colorimetric Estimation of Ni(II Ions in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    S. Mathpal

    2009-01-01

    Full Text Available A rapid and accurate colorimetric method has been proposed for the estimation of nickel(II in aqueous solution. It is found that nickel(II ions have maximum absorbance at 393 nm in distilled water and in aqueous sucrose solution (0.3 mol dm-3. In both case, the Beer’s law was obeyed over the range from 0.04 to 0.08 mol dm -3 of nickel(II.The value of molar absorpitivity was constant 5.13±0.03 mol dm-3. This method is more rapid than the existing spectrophotometeric methods for the estimation of nickel(II. The variation in the results obtained by the method is ±2.1%.

  3. Colorimetric detection of ammonia using smartphones based on localized surface plasmon resonance of silver nanoparticles.

    Science.gov (United States)

    Amirjani, Amirmostafa; Fatmehsari, Davoud Haghshenas

    2018-01-01

    In this work, a rapid and straightforward method was developed for colorimetric determination of ammonia using smartphones. The mechanisms is based on the manipulation of the surface plasmon band of silver nanoparticles (AgNPs) via the formation of Ag (NH 3 ) 2 + complex. This complex decreases the amount of AgNPs in the solution and consequently, the color intensity of the colloidal system decreases. Not only the variation in color intensity of the solution can be tracked by a UV-vis spectrophotometer, but also a smartphone can be employed to monitor the color intensity variation by RGB analysis. Ammonia, in the concentration range of 10-1000mgL -1 , was successfully measured spectrophotometrically (UV-vis spectrophotometer) and colorimetrically (RGB measurement) with the detection limit of 180 and 200mgL -1 , respectively. Linear relationships were also developed for both methods. Also, the response time of the developed colorimetric sensor was around 20s. Both of the colorimetric and spectrophotometric methods showed a reliable performance for determination of ammonia in the real samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Evaluation of the β-CARBA™ test, a colorimetric test for the rapid detection of carbapenemase activity in Gram-negative bacilli.

    Science.gov (United States)

    Bernabeu, Sandrine; Dortet, Laurent; Naas, Thierry

    2017-06-01

    There is an urgent need for accurate and fast diagnostic tests to identify carbapenemase-producing bacteria. Here, we have evaluated a novel colorimetric test (the β-CARBA™ test; Bio-Rad) to detect carbapenemase-producing Gram-negative bacilli from cultured colonies. The performance of the β-CARBA™ test was compared with that of the Carba NP test (or the CarbAcineto NP test) and RAPIDEC ® CARBA NP (bioMérieux) using a collection of 290 isolates with characterized β-lactamase content. This collection included 199 carbapenemase producers (121 Enterobacteriaceae, 36 Pseudomonas and 42 Acinetobacter baumannii ) and 91 non-carbapenemase producers (55 Enterobacteriaceae, 20 Pseudomonas and 16 A. baumannii ). The β-CARBA™ test correctly detected 84.9% of the carbapenemase producers, including all KPC and IMP, 96.4% of VIM, 85.3% of NDM, 80.5% of OXA-48-like and 91.2% of A. baumannii -related OXA carbapenemases (OXA-23, OXA-40, OXA-58, OXA-143 and overexpressed OXA-51). All rare metallo-β-lactamases (SPM, AIM, GIM, DIM and SIM) were detected. Importantly, all non-KPC Ambler class A carbapenemases were not detected, including GES variants with carbapenemase activity ( n  = 6), IMI ( n  = 3), NMC-A ( n  = 1), SME ( n  = 2), FRI-1 ( n  = 1) and BIC-1 ( n  = 1). All non-carbapenemase producers gave a negative result except with OXA-163-, OXA-405- and one TEM-3-producing Citrobacter freundii . The overall sensitivity and specificity of the β-CARBA™ test were 84.9% and 95.6%, respectively. This test is easy to perform and to interpret by non-specialized staff members. Despite lack of specificity towards non-KPC Ambler class A and OXA-48-like carbapenemases, the β-CARBA™ test could complete the existing panel of tests available for the confirmation of carbapenemases in Gram-negatives.

  5. Detection of beer spoilage bacteria Megasphaera and Pectinatus by polymerase chain reaction and colorimetric microplate hybridization.

    Science.gov (United States)

    Satokari, R; Juvonen, R; Mallison, K; von Wright, A; Haikara, A

    1998-12-08

    Anaerobic bacteria of the genera Megasphaera and Pectinatus cause beer spoilage by producing off flavours and turbidity. Detection of these organisms is complicated by the strict anaerobic conditions and lengthy incubation times required for their cultivation, consequently there is a need for more rapid detection methods. A polymerase chain reaction (PCR) method and a colorimetric microplate hybridization assay were developed for the rapid and specific detection of Megasphaera cerevisiae and Pectinatus spp. A biotinylated primer pair was designed for the amplification of a 403 base pair (bp) fragment of the M. cerevisiae 16S rRNA gene and a primer pair from literature was used for the amplification of an 816 bp fragment of Pectinatus 16S rRNA gene. Amplified PCR products were analyzed by the colorimetric microplate hybridization method in which a biotinylated PCR product was captured by streptavidin and hybridized with a digoxigenin-labelled oligonucleotide probe. In the final step an enzyme-linked antibody and a colorimetric reaction were utilized. A simple and rapid sample treatment was set up for the PCR detection of contaminants in beer. Detection of M. cerevisiae (> or = 5 x 10(3) colony forming units [cfu]/100 ml) and Pectinatus frisingensis (> or = 5 x 10(5) cfu/100 ml) in beer was successful, but the sensitivity of the assay still needs to be improved for direct detection of the small amounts of bacteria present in beer.

  6. A sensitive colorimetric method for the determination of nitrite in water supplies, meat and dairy products using ionic liquid-modified methyl red as a colour reagent.

    Science.gov (United States)

    Zhang, Haijuan; Qi, Shengda; Dong, Yalei; Chen, Xiaojiao; Xu, Yinyin; Ma, Yanhua; Chen, Xingguo

    2014-05-15

    This paper describes a colorimetric approach to determine trace amounts of nitrite in water supplies, meat and dairy products using 1-butyl-3-methylimidazolium-modified methyl red ([BMIM]MR) as a colour reagent. The technique capitalises on the catalytic effect of nitrite on the oxidative degradation of [BMIM]MR by potassium bromate in acidic media. The absorbances were proportional to nitrite concentrations in the range of 8.70×10(-2) to 4.17 μM with a detection limit of 1.64×10(-2) μM. Compared with the method using methyl red as a colour reagent, 60 times improvement of sensitivity was obtained. Activation energy and the apparent rate constant for the catalytic reaction are 61.11 kJ mol(-1) and 1.18×10(4) s(-1), respectively. The proposed method was successfully applied for the analysis of nitrite in Yellow River water, chicken, and milk with recoveries ranging from 96% to 105%. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Rapid method for detection of salmonella in meat

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a rapid method for the detection of Salmonella in meat as well as to a kit for performing said method. The method provides a time-to-result of less than 8 hours.......The present invention relates to a rapid method for the detection of Salmonella in meat as well as to a kit for performing said method. The method provides a time-to-result of less than 8 hours....

  8. Visualizing Capsaicinoids: Colorimetric Analysis of Chili Peppers

    Science.gov (United States)

    Thompson, Robert Q.; Chu, Christopher; Gent, Robin; Gould, Alexandra P.; Rios, Laura; Vertigan, Theresa M.

    2012-01-01

    A colorimetric method for total capsaicinoids in chili pepper ("Capsicum") fruit is described. The placental material of the pepper, containing 90% of the capsaicinoids, was physically separated from the colored materials in the pericarp and extracted twice with methanol, capturing 85% of the remaining capsaicinoids. The extract, evaporated and…

  9. Methods and compositions for rapid thermal cycling

    Science.gov (United States)

    Beer, Neil Reginald; Benett, William J.; Frank, James M.; Deotte, Joshua R.; Spadaccini, Christopher

    2015-10-27

    The rapid thermal cycling of a material is targeted. A microfluidic heat exchanger with an internal porous medium is coupled to tanks containing cold fluid and hot fluid. Fluid flows alternately from the cold tank and the hot tank into the porous medium, cooling and heating samples contained in the microfluidic heat exchanger's sample wells. A valve may be coupled to the tanks and a pump, and switching the position of the valve may switch the source and direction of fluid flowing through the porous medium. A controller may control the switching of valve positions based on the temperature of the samples and determined temperature thresholds. A sample tray for containing samples to be thermally cycled may be used in conjunction with the thermal cycling system. A surface or internal electrical heater may aid in heating the samples, or may replace the necessity for the hot tank.

  10. Rapid colorimetric detection of Zika virus from serum and urine specimens by reverse transcription loop-mediated isothermal amplification (RT-LAMP).

    Science.gov (United States)

    Calvert, Amanda E; Biggerstaff, Brad J; Tanner, Nathan A; Lauterbach, Molly; Lanciotti, Robert S

    2017-01-01

    Zika virus (ZIKV) has emerged as a major global public health concern in the last two years due to its link as a causative agent of human birth defects. Its rapid expansion into the Western Hemisphere as well as the ability to be transmitted from mother to fetus, through sexual transmission and possibly through blood transfusions has increased the need for a rapid and expansive public health response to this unprecedented epidemic. A non-invasive and rapid ZIKV diagnostic screening assay that can be performed in a clinical setting throughout pregnancy is vital for prenatal care of women living in areas of the world where exposure to the virus is possible. To meet this need we have developed a sensitive and specific reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) assay to detect ZIKV RNA in urine and serum with a simple visual detection. RT-LAMP results were shown to have a limit of detection 10-fold higher than qRT-PCR. As little as 1.2 RNA copies/μl was detected by RT-LAMP from a panel of 178 diagnostic specimens. The assay was shown to be highly specific for ZIKV RNA when tested with diagnostic specimens positive for dengue virus (DENV) and chikungunya virus (CHIKV). The assay described here illustrates the potential for a fast, reliable, sensitive and specific assay for the detection of ZIKV from urine or serum that can be performed in a clinical or field setting with minimal equipment and technological expertise.

  11. Photoacoustic and Colorimetric Visualization of Latent Fingerprints.

    Science.gov (United States)

    Song, Kai; Huang, Peng; Yi, Chenglin; Ning, Bo; Hu, Song; Nie, Liming; Chen, Xiaoyuan; Nie, Zhihong

    2015-12-22

    There is a high demand on a simple, rapid, accurate, user-friendly, cost-effective, and nondestructive universal method for latent fingerprint (LFP) detection. Herein, we describe a combination imaging strategy for LFP visualization with high resolution using poly(styrene-alt-maleic anhydride)-b-polystyrene (PSMA-b-PS) functionalized gold nanoparticles (GNPs). This general approach integrates the merits of both colorimetric imaging and photoacoustic imaging. In comparison with the previous methods, our strategy is single-step and does not require the signal amplification by silver staining. The PSMA-b-PS functionalized GNPs have good stability, tunable color, and high affinity for universal secretions (proteins/polypeptides/amino acids), which makes our approach general and flexible for visualizing LFPs on different substrates (presumably with different colors) and from different people. Moreover, the unique optical property of GNPs enables the photoacoustic imaging of GNPs-deposited LFPs with high resolution. This allows observation of level 3 hyperfine features of LFPs such as the pores and ridge contours by photoacoustic imaging. This technique can potentially be used to identify chemicals within LFP residues. We believe that this dual-modality imaging of LFPs will find widespread use in forensic investigations and medical diagnostics.

  12. Evaluation of the accuracy of the microplate Alamar Blue assay for rapid detection of MDR-TB in Peru [Short Communication

    National Research Council Canada - National Science Library

    Chauca, J.A; Palomino, J-C; Guerra, H

    2007-01-01

    .... This study evaluates the usefulness of the colorimetric method using Alamar Blue for the rapid detection of resistance to rifampicin and isoniazid in 63 clinical isolates of Mycobacterium tuberculosis in Peru...

  13. Rapid colorimetric detection of Zika virus from serum and urine specimens by reverse transcription loop-mediated isothermal amplification (RT-LAMP.

    Directory of Open Access Journals (Sweden)

    Amanda E Calvert

    Full Text Available Zika virus (ZIKV has emerged as a major global public health concern in the last two years due to its link as a causative agent of human birth defects. Its rapid expansion into the Western Hemisphere as well as the ability to be transmitted from mother to fetus, through sexual transmission and possibly through blood transfusions has increased the need for a rapid and expansive public health response to this unprecedented epidemic. A non-invasive and rapid ZIKV diagnostic screening assay that can be performed in a clinical setting throughout pregnancy is vital for prenatal care of women living in areas of the world where exposure to the virus is possible. To meet this need we have developed a sensitive and specific reverse transcriptase loop-mediated isothermal amplification (RT-LAMP assay to detect ZIKV RNA in urine and serum with a simple visual detection. RT-LAMP results were shown to have a limit of detection 10-fold higher than qRT-PCR. As little as 1.2 RNA copies/μl was detected by RT-LAMP from a panel of 178 diagnostic specimens. The assay was shown to be highly specific for ZIKV RNA when tested with diagnostic specimens positive for dengue virus (DENV and chikungunya virus (CHIKV. The assay described here illustrates the potential for a fast, reliable, sensitive and specific assay for the detection of ZIKV from urine or serum that can be performed in a clinical or field setting with minimal equipment and technological expertise.

  14. Systematic comparisons of various spectrophotometric and colorimetric methods to measure concentrations of protein, peptide and amino acid: detectable limits, linear dynamic ranges, interferences, practicality and unit costs.

    Science.gov (United States)

    Chutipongtanate, Somchai; Watcharatanyatip, Kamolwan; Homvises, Teerada; Jaturongkakul, Kewalee; Thongboonkerd, Visith

    2012-08-30

    There is limited and inconclusive information regarding detectable limits and linear dynamic ranges of various quantitative protein assays. We thus performed systematic comparisons of seven commonly used methods, including direct spectrophotometric quantitation at λ205 and λ280 nm (A205 and A280, respectively), bicinchoninic acid (BCA), Biuret, Bradford, Lowry and Ninhydrin methods. Purified BSA, porcine kidney extract, tryptic digested peptides derived from purified BSA, and glycine, were used as representative purified protein, complex protein mixture, peptide and amino acid, respectively. Bradford method was the most sensitive assay (LOD=0.006 mg/ml) and had the widest range of detectability (LOD-UOD=0.006-100mg/ml) for purified protein and complex protein mixture. For peptide, A205, A280, Lowry and Ninhydrin methods had a comparable LOD (0.006 mg/ml), but Ninhydrin method had the widest detectability range (LOD-UOD=0.006-100mg/ml). For amino acid, A205 and Ninhydrin methods had a comparable LOD (0.006 mg/ml), but A205 had a wider detectability range (LOD-UOD=0.006-6.250 mg/ml). Biuret method offered the widest linear dynamic range for purified protein and complex protein mixture (0.391-100mg/ml), A280 offered the widest linear dynamic range for peptide (0.024-6.250 mg/ml), and Ninhydrin method offered the widest linear dynamic range for amino acid (0.024-0.195 mg/ml). Both Laemmli's and 2-D lysis buffers had dramatic interfering effects on all assays. Concerning the practicality and unit costs, A205 and A280 were the most favorable. Among the colorimetric methods, Bradford method consumed the least amount of samples and shortest analytical time with the lowest unit cost. These are the most extensive comparative data of commonly used quantitative protein assays that will be useful for selecting the most suitable method for each study. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Optimization, validation and application of UV-Vis spectrophotometric-colorimetric methods for determination of trimethoprim in different medicinal products

    OpenAIRE

    Goran Stojković; Elizabeta Dimitrieska-Stojković; Marija Soklevska; Romel Velev

    2016-01-01

    Two simple, sensitive, selective, precise, and accurate methods for determination of trimethoprim in different sulfonamide formulations intended for use in human and veterinary medicine were optimized and validated. The methods are based on the trimethoprim reaction with bromcresol green (BCG) and 2,4-dinitro-1-fluorobenzene (DNFB). As extraction solvents we used 10 % N,N-dimethylacetamide in methanol and acetone for both methods, respectively. The colored products are quantified applying vis...

  16. An organic indicator functionalized graphene oxide nanocomposite-based colorimetric assay for the detection of sarcosine

    Science.gov (United States)

    Xue, Zhonghua; Yin, Bo; Wang, Hui; Li, Mengqian; Rao, Honghong; Liu, Xiuhui; Zhou, Xinbin; Lu, Xiaoquan

    2016-03-01

    Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS functionalized GO nanocomposite through π-π stacking has been demonstrated to be useful as a highly efficient catalyst system for the selective and sensitive colorimetric determination of sarcosine by providing a nanocomposite-amplified colorimetric response. Meanwhile, the strategy offered excellent selectivity toward sarcosine species against other amino acids as well as a satisfying detection limit of 0.73 μM. More importantly, by using an electrochemical method, a credible sensing mechanism of GO nanocomposite-based colorimetric platform for a special analyte determination can be easily verified and elucidated, which also provides an attractive alternative to conventional characterization strategies.Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS

  17. Could colorimetric method replace the individual minimal erythemal dose (MED) measurements in determining the initial dose of narrow-band UVB treatment for psoriasis patients with skin phototype III-V?

    Science.gov (United States)

    Kwon, I H; Kwon, H H; Na, S J; Youn, J I

    2013-04-01

    Assessment of minimal erythemal dose (MED) for individual patients has been used to guide the narrowband Ultraviolet B (NB-UVB) phototherapy, which sometimes causes discomfort and additional time. The L* value (the lightness of color in Commission Internationlale de l'Eclairge L*a*b* color scale) measured by colorimeter was shown to be useful for predicting sensitivity to NB-UVB irradiation. To compare the efficacy and safety of NB-UVB phototherapy between 50% of MED and colorimetric L* value starting dose regimens for skin phototype III-V Korean patients with psoriasis. Twenty seven patients determined starting doses based on colorimetric L* value, and 27 patients based on 50% of MED. Since correlation analysis showed that L* value had the most significant association with MED compared with skin phototypes, a*, and b* values, we designated starting doses of L* value regimen as follows: 300 mJ/cm(2) (L* >66), 400 mJ/cm(2) (62 MED based regimen in efficacy and safety for skin phototype III-V patients. Since it provides much convenience and ease for both patients and physicians, colorimetric L* value could partly substitute the MED checking methods in NB-UVB phototherapy. © 2012 The Authors. Journal of the European Academy of Dermatology and Venereology © 2012 European Academy of Dermatology and Venereology.

  18. Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang, E-mail: panyuanjiang@zju.edu.cn

    2016-01-01

    In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu{sup 2+} through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10{sup −3}–10{sup −6} M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments. - Highlights: • A novel task-specific ionic liquid functionalized gold nanoparticle was successfully prepared. • This material was successfully applied to recognizing five amino acids with Cu(II) through distinctive color changes. • The proposed strategy was successfully used to analyze the histidine in real samples.

  19. Validation of a user-friendly and rapid method for quantifying iodine content of salt.

    Science.gov (United States)

    Rohner, Fabian; Garrett, Greg S; Laillou, Arnaud; Frey, Simone K; Mothes, Ralf; Schweigert, Florian J; Locatelli-Rossi, Lorenzo

    2012-12-01

    Despite considerable progress made in the past decade through salt iodization programs, over 2 billion people worldwide still have inadequate iodine intake, with devastating consequences for brain development and intellectual capacity. To optimize these programs with regard to salt iodine content, careful monitoring of salt iodine content is essential, but few methods are available to quantitatively measure iodine concentration in a simple, fast, and safe way. We have validated a newly developed device that quantitatively measures the content of potassium iodate in salt in a simple, safe, and rapid way. The linearity, determination and detection limit, and inter- and intra-assay variability of this colorimetric method were assessed and the method was compared with iodometric titration, using salt samples from several countries. Linearity of analysis ranged from 5 to 75 mg/kg iodine, with 1 mg/kg being the determination limit; the intra- and interassay imprecision was 0.9%, 0.5%, and 0.7% and 1.5%, 1.7%, and 2.5% for salt samples with iodine contents of 17, 30, and 55 mg/kg, respectively; the interoperator imprecision for the same samples was 1.2%, 4.9%, and 4.7%, respectively. Comparison with the iodometric method showed high agreement between the methods (R2 = 0.978; limits of agreement, -10.5 to 10.0 mg/kg). The device offers a field- and user-friendly solution to quantifying potassium iodate salt content reliably. For countries that use potassium iodide in salt iodization programs, further validation is required.

  20. Rapid determination of lipid peroxidation using a novel pyridoxamine-participating ferrous oxidation-sulfosalicylic acid spectrophotometric method.

    Science.gov (United States)

    Chen, Jingnan; Cai, Danqian; Zhang, Yu

    2016-11-15

    A novel method is developed to rapidly analyze lipid peroxidation in edible oils and fatty foods at room temperature, which is called the pyridoxamine-participating ferrous oxidation-sulfosalicylic acid (PFOS) method. The PFOS method evaluates the lipid peroxide value colorimetrically via detecting the pyridoxamine-mediated pigment produced by 5-sulfosalicylic acid and Fe(3+) at 500nm, while the latter is converted from Fe(2+) in the presence of lipid peroxides. The optimized formulation was ethanol (70%, v/v), Fe(2+) (4mmol/L), 5-sulfosalicylic acid (40mmol/L) and pyridoxamine (18mmol/L). The limit of quantitation is 0.087mmol Fe(3+)/L with acceptable reproducibility. In addition, current method has a significant linear correlation with both conventional thiobarbituric acid (R(2)=0.9999) and ferric thiocyanate assays (R(2)=0.9675). This method offers a rapid technique for evaluating lipid peroxidation without heating and sophisticated instrumental procedures. Besides, current method provides a new option to evaluate the lipid peroxidation state and improve the reproducibility of ferrous-oxidation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Effective staining method with iodine for leukoplakia and lesions surrounding squamous cell carcinomas of the tongue assessed by colorimetric analysis.

    Science.gov (United States)

    Maeda, Keiko; Yamashiro, Masashi; Michi, Yasuyuki; Suzuki, Tetsuo; Ohyama, Yoshio; Okada, Norihiko; Amagasa, Teruo

    2009-12-01

    To determine whether staining with iodine solution provides an efficient criterion for determining the area of resection for the lesions surrounding squamous cell carcinoma (SCC) and leukoplakia of the tongue, we determined the optimum density of iodine solution and staining procedure and analyzed the color of lightly stained lesions (LSLs) in relation to the histopathologic findings. Sixty-five patients with SCC or leukoplakia of the tongue were divided into two groups: lesions stained with 3% Lugol solution and restained with either 5% Lugol solution (n=38) or 10% iodine glycerin (n=27). Among the lesions stained with 5% Lugol solution, significant differences were found in all color values. Color difference values (DeltaE*ab) using 3% and 5% Lugol solutions were significantly different between epithelial hyperplasia/mild epithelial dysplasia and moderate to severe dysplasia (P Lugol solution. These results suggest that the most effective method for obtaining a clear boundary and distinguishing moderate to severe dysplasia from mild or no epithelial dysplasia according to the measured color value was to stain with 3% followed by 5% Lugol solution.

  2. A sensitive colorimetric assay system for nucleic acid detection based on isothermal signal amplification technology.

    Science.gov (United States)

    Hu, Bo; Guo, Jing; Xu, Ying; Wei, Hua; Zhao, Guojie; Guan, Yifu

    2017-08-01

    Rapid and accurate detection of microRNAs in biological systems is of great importance. Here, we report the development of a visual colorimetric assay which possesses the high amplification capabilities and high selectivity of the rolling circle amplification (RCA) method and the simplicity and convenience of gold nanoparticles used as a signal indicator. The designed padlock probe recognizes the target miRNA and is circularized, and then acts as the template to extend the target miRNA into a long single-stranded nucleotide chain of many tandem repeats of nucleotide sequences. Next, the RCA product is hybridized with oligonucleotides tagged onto gold nanoparticles. This interaction leads to the aggregation of gold nanoparticles, and the color of the system changes from wine red to dark blue according to the abundance of miRNA. A linear correlation between fluorescence and target oligonucleotide content was obtained in the range 0.3-300 pM, along with a detection limit of 0.13 pM (n = 7) and a RSD of 3.9% (30 pM, n = 9). The present approach provides a simple, rapid, and accurate visual colorimetric assay that allows sensitive biodetection and bioanalysis of DNA and RNA nucleotides of interest in biologically important samples. Graphical abstract The colorimetric assay system for analyzing target oligonucleotides.

  3. Determination of chemical oxygen demand in heterogeneous solid or semisolid samples using a novel method combining solid dilutions as a preparation step followed by optimized closed reflux and colorimetric measurement.

    Science.gov (United States)

    Noguerol-Arias, Joan; Rodríguez-Abalde, Angela; Romero-Merino, Eva; Flotats, Xavier

    2012-07-03

    This paper reports the development of an innovative sample preparation method for the determination of the chemical oxygen demand (COD) in heterogeneous solid or semisolid samples, with high suspended solids and COD concentrations, using an optimized closed reflux colorimetric method. The novel method, named solid dilution (SD), is based on a different technique of sample preparation, diluting the sample with magnesium sulfate (MgSO(4)) previous to COD determination. With this, it is possible to obtain a solid homogeneous mixture much more easily analyzable. Besides, a modification of concentration and ratio of reagents was optimized to make the closed reflux colorimetric method suitable for complex substrates with COD levels ranging from 5 to 2500 g O(2) kg(-1) TS. The optimized method has been tested with potassium hydrogen phthalate (KHP) as primary solid standard and using different solid or semiliquid substrates like pig slaughterhouse waste and sewage sludge, among others. Finally, the optimized method (SD/SM-CRC) was intensively tested in comparison to the standard titrimetric method (SM-ORT) using different certified reference materials (CRM). The developed method was found to give higher accuracy, 1.4% relative standard deviation (RSD) vs 10.4%, and bias of 2.8% vs 8.0%, in comparison to the standard open reflux titrimetric method.

  4. RAPID METHOD FOR DETERMINATION OF RADIOSTRONTIUM IN EMERGENCY MILK SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Culligan, B.

    2008-07-17

    A new rapid separation method for radiostrontium in emergency milk samples was developed at the Savannah River Site (SRS) Environmental Bioassay Laboratory (Aiken, SC, USA) that will allow rapid separation and measurement of Sr-90 within 8 hours. The new method uses calcium phosphate precipitation, nitric acid dissolution of the precipitate to coagulate residual fat/proteins and a rapid strontium separation using Sr Resin (Eichrom Technologies, Darien, IL, USA) with vacuum-assisted flow rates. The method is much faster than previous method that use calcination or cation exchange pretreatment, has excellent chemical recovery, and effectively removes beta interferences. When a 100 ml sample aliquot is used, the method has a detection limit of 0.5 Bq/L, well below generic emergency action levels.

  5. High-sensitive and high-efficient biochemical analysis method using a bionic electronic eye in combination with a smartphone-based colorimetric reader system.

    Science.gov (United States)

    Kaiqi Su; Quchao Zou; Ning Hu; Ping Wang

    2015-01-01

    Bionic electronic eye (Bionic e-Eye), a developed smartphone-based colorimetric reader system, consists of smartphone or pad (iPhone 4s or iPad 3) as detection instrument and portable accessory as illumination provider, integrating with a wide-angle lens, a piece of lowest-power electro luminescent and a custom-made dark hood. A 96-well microtiter plate (MTP) was positioned on the electro luminescent and Bionic e-Eye captures the detection images by the back camera of smartphone. Being similar to human visual system, the hue, saturation and value (HSV, also called hex cone model) color model was employed in image processing algorithm of Bionic e-Eye. Optimized system dimension was determined by the system steadiness experiment of different photograph distances. Moreover, the commercially available BCA protein assay and CCK8 cell number assay were carried out to evaluate this Bionic e-Eye. Analytical performance of Bionic e-Eye had the better precision, higher sensitivity than microtiter plate reader (MTPR) and previous smartphone-based colorimetric reader for both two assays. Also, Bionic e-Eye using optical image detection had simultaneous and synchronous working mode, while MPTR using machine moving detection had asynchronous working mode in high throughput detection. Therefore, Bionic e-Eye will be an ideal point-of-care (POC) colorimetric detection device in the field of clinical application, industrial quality control, environment monitoring, and food assessment.

  6. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of the total phosphorus by a Kjeldahl digestion method and an automated colorimetric finish that includes dialysis

    Science.gov (United States)

    Patton, Charles J.; Truitt, Earl P.

    1992-01-01

    A method to determine total phosphorus (TP) in the same digests prepared for total Kjeldahl nitrogen (TKN) determinations is desribed. The batch, high-temperature (block digester), HG(II)-catalyzed digestion step is similar to U.S. Geological Survey methods I-2552-85/I-4552-85 and U.S. Environmental Protection Agency method 365.4 except that sample and reagent volumes are halved. Prepared digests are desolvated at 220 degrees Celsius and digested at 370 degrees Celsius in separate block digesters set at these temperatures, rather than in a single, temperature-programmed block digester. This approach is used in the method escribed here, which permits 40 calibrants, reference waters, and smaples to be digested and resolvated in about an hour. Orthophosphate ions originally present in samples, along with those released during the digestion step, are determined colorimetrically at a rate of 90 tests per hour by an automated version of the phosphoantimonylmolybdenum blue procedure. About 100 microliters of digest are required per determination. The upper concentration limit is 2 milligrams per liter (mg/L) with a method detection limt of 0.01 mg/L. Repeatability for a sample containing approximately 1.6 mg/L of TP in a high suspended-solids matrix is 0.7 percent. Between-day precision for the same sample is 5.0 percent. A dialyzer in the air-segmented continuous flow analyzer provides on-line digest cleanup, eliminated particulates that otherwise would interfere in the colorimetric finish. An single-channel analyzer can process the resolvated digests from two pairs of block digesters each hour. Paired t-test analysis of TP concentrations for approximately 1,600 samples determined by the new method (U.S. Geologial Survey methods I-2610-91 and I-4610-91) and the old method (U.S. Geological Survey methods I-2600-85 and I-4600-85) revealed positive bias in the former of 0.02 to 0.04 mg/L for surface-water samples in agreement with previous studies. Concentrations of total

  7. A universal, rapid, and inexpensive method for genomic DNA ...

    Indian Academy of Sciences (India)

    MOHAMMED BAQUR SAHIB A. AL-SHUHAIB

    Abstract. There is no 'one' procedure for extracting DNA from the whole blood of both mammals and birds, since each species has a unique property that require different methods to release its own DNA. Therefore, to obtain genomic DNA, a universal, rapid, and noncostly method was developed. A very simple biological ...

  8. Rapid, cost-effective liquid chromatograghic method for the ...

    African Journals Online (AJOL)

    GRACE

    2006-07-03

    Jul 3, 2006 ... 1Department of Medicinal Chemistry and Quality Control, National Institute for Pharmaceutical Research and Development, Abuja,. Nigeria. ... A rapid and cost effective method for the analysis of metronidazole in biological samples was ... effective HPLC method of assaying metronidazole both in.

  9. A universal, rapid, and inexpensive method for genomic DNA ...

    Indian Academy of Sciences (India)

    ... of both mammals and birds, since each species has a unique property that require different methods to release its own DNA. Therefore, to obtain genomic DNA, a universal, rapid, and noncostly method was developed. A very simple biological basis is followed in this procedure, in which, when the bloodis placed in water, ...

  10. Exploiting pH-Regulated Dimer-Tetramer Transformation of Concanavalin A to Develop Colorimetric Biosensing of Bacteria.

    Science.gov (United States)

    Xu, Xiahong; Yuan, Yuwei; Hu, Guixian; Wang, Xiangyun; Qi, Peipei; Wang, Zhiwei; Wang, Qiang; Wang, Xinquan; Fu, Yingchun; Li, Yanbin; Yang, Hua

    2017-05-03

    Gold nanoparticles (AuNPs) aggregation-based colorimetric biosensing remains a challenge for bacteria due to their large size. Here we propose a novel colorimetric biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7) in milk samples based on pH-regulated transformation of dimer/tetramer of Concanavalin A (Con A) and the Con A-glycosyl recognition. Briefly, antibody-modified magnetic nanoparticles was used to capture and concentrate E. coli O157:H7 and then to label with Con A; pH adjusted to 5 was then applied to dissociate Con A tetramer to release dimer, which was collected and re-formed tetramer at pH of 7 to cause the aggregation of dextran-modified AuNPs. The interesting pH-dependent conformation-transformation behavior of Con A innovated the design of the release from the bacteria surface and then the reconstruction of Con A. Therefore, we realized the sensitive colorimetric biosensing of bacteria, which are much larger than AuNPs that is generally not suitable for this kind of method. The proposed biosensor exhibited a limit of detection down to 41 CFU/mL, short assay time (~95 min) and satisfactory specificity. The biosensor also worked well for the detection in milk sample, and may provide a universal concept for the design of colorimetric biosensors for bacteria and virus.

  11. Methods for Rapid Screening in Woody Plant Herbicide Development

    Directory of Open Access Journals (Sweden)

    William Stanley

    2014-07-01

    Full Text Available Methods for woody plant herbicide screening were assayed with the goal of reducing resources and time required to conduct preliminary screenings for new products. Rapid screening methods tested included greenhouse seedling screening, germinal screening, and seed screening. Triclopyr and eight experimental herbicides from Dow AgroSciences (DAS 313, 402, 534, 548, 602, 729, 779, and 896 were tested on black locust, loblolly pine, red maple, sweetgum, and water oak. Screening results detected differences in herbicide and species in all experiments in much less time (days to weeks than traditional field screenings and consumed significantly less resources (<500 mg acid equivalent per herbicide per screening. Using regression analysis, various rapid screening methods were linked into a system capable of rapidly and inexpensively assessing herbicide efficacy and spectrum of activity. Implementation of such a system could streamline early-stage herbicide development leading to field trials, potentially freeing resources for use in development of beneficial new herbicide products.

  12. Methods and systems for rapid prototyping of high density circuits

    Science.gov (United States)

    Palmer, Jeremy A [Albuquerque, NM; Davis, Donald W [Albuquerque, NM; Chavez, Bart D [Albuquerque, NM; Gallegos, Phillip L [Albuquerque, NM; Wicker, Ryan B [El Paso, TX; Medina, Francisco R [El Paso, TX

    2008-09-02

    A preferred embodiment provides, for example, a system and method of integrating fluid media dispensing technology such as direct-write (DW) technologies with rapid prototyping (RP) technologies such as stereolithography (SL) to provide increased micro-fabrication and micro-stereolithography. A preferred embodiment of the present invention also provides, for example, a system and method for Rapid Prototyping High Density Circuit (RPHDC) manufacturing of solderless connectors and pilot devices with terminal geometries that are compatible with DW mechanisms and reduce contact resistance where the electrical system is encapsulated within structural members and manual electrical connections are eliminated in favor of automated DW traces. A preferred embodiment further provides, for example, a method of rapid prototyping comprising: fabricating a part layer using stereolithography and depositing thermally curable media onto the part layer using a fluid dispensing apparatus.

  13. A rapid ultrasound particle agglutination method for HIV antibody detection: Comparison with conventional rapid HIV tests.

    Science.gov (United States)

    Bystryak, Simon; Ossina, Natalya

    2017-11-01

    We present the results of the feasibility and preliminary studies on analytical performance of a rapid test for detection of human immunodeficiency virus (HIV) antibodies in human serum or plasma that is an important advance in detecting HIV infection. Current methods for rapid testing of antibodies against HIV are qualitative and exhibit poor sensitivity (limit of detection). In this paper, we describe an ultrasound particle agglutination (UPA) method that leads to a significant increase of the sensitivity of conventional latex agglutination tests for HIV antibody detection in human serum or plasma. The UPA method is based on the use of: 1) a dual mode ultrasound, wherein a first single-frequency mode is used to accelerate the latex agglutination process, and then a second swept-frequency mode of sonication is used to disintegrate non-specifically bound aggregates; and 2) a numerical assessment of results of the agglutination process. The numerical assessment is carried out by optical detection and analysis of moving patterns in the resonator cell during the swept-frequency mode. The single-step UPA method is rapid and more sensitive than the three commercial rapid HIV test kits analyzed in the study: analytical sensitivity of the new UPA method was found to be 510-, 115-, and 80-fold higher than that for Capillus™, Multispot™ and Uni-Gold™ Recombigen HIV antibody rapid test kits, respectively. The newly developed UPA method opens up additional possibilities for detection of a number of clinically significant markers in point-of-care settings. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A novel biphenolic ligand for selective Mg2+and Zn2+ions sensing followed by colorimetric, spectroscopic and cell imaging methods.

    Science.gov (United States)

    Maheswari, Palanisamy Uma; Renuga, Duraisamy; Jeeva Kumari, H L; Ruckmani, Kandasamy

    2018-01-12

    The (E)-2-((2-hydrohy-5-methylphenylimino) methyl) phenol ligand was synthesized. The receptor was characterized by IR, 1 H and 13 C NMR and CHN analysis. The ligand exhibits colorimetric and fluorometric sensing of Zn 2+ and Mg 2+ ions in semi-aqueous medium (DMSO-H2O). The receptor was tested with series of transition metal ions (Cr 2+ , Fe 2+ , Ni 2+ , Co 2+ , Cu 2+ , Zn 2+ ) and heavy metal ions (Sn 2+ , Pd 2+ , Ce 2+ , Hg 2+ , Cd 2+ ) and the essential human body elements like Ca 2+ , Mg 2+ , Na + and K + ions. The naked eye colorimetric sensing was absorbed only for Zn 2+ and Mg 2+ . Both ions (ZnCl 2 and MgCl 2 in H 2 O), when added to the colorless solutions of the receptor of about 1 equivalence in incremental additions turn the solution into bright turmeric yellow. All other ions remain inactive, in colorimetric sensing. Further the Zn 2+ and Mg 2+ ions were probed by absorption and emission spectroscopy through incremental addition of respective metal ions. The in-situ deprotonation of the ligand on both Mg 2+ and Zn 2+ ions binding was confirmed by 1 H NMR titration studies. The imino nitrogen of the receptor is not coordinated to the metal ions. The Job's plot studies reveal the 1:2 binding ratio of metal ions to the receptor. The high fold fluorescence output on metal ions binding was positively used to sense the Zn 2+ and Mg 2+ ions, separately and together in HeLa cancer cells through cell imaging. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY SOIL SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Culligan, B.; Noyes, G.

    2009-11-09

    A new rapid method for the determination of actinides in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for samples up to 2 grams in emergency response situations. The actinides in soil method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride soil matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA Resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA Resin. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha sources are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency soil samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinides in soil results were reported within 4-5 hours with excellent quality.

  16. Rapid method to estimate temperature changes in electronics elements

    Directory of Open Access Journals (Sweden)

    Oborskii G. A., Savel’eva O. S., Shikhireva Yu. V.

    2014-06-01

    Full Text Available Thermal behavior of electronic equipment is the determining factor for performing rapid assessment of the effectiveness of design and operation of the equipment. The assessment method proposed in this article consists in fixation of an infrared video stream from the surface of the device and converting it into a visible flow by means of a thermal imager, splitting it into component colors and their further processing using parabolic transformation. The result of the transformation is the number used as a rapid criterion for estimation of distribution stability of heat in the equipment.

  17. Colorimetric Sensor Array Based on Gold Nanoparticles with Diverse Surface Charges for Microorganisms Identification.

    Science.gov (United States)

    Li, Bingyu; Li, Xizhe; Dong, Yanhua; Wang, Bing; Li, Dongyang; Shi, Youmin; Wu, Yayan

    2017-10-17

    We report a simple and novel colorimetric sensor array for rapid identification of microorganisms. In this study, four gold nanoparticles (AuNPs) with diverse surface charges were used as sensing elements. The interactions between AuNPs and microorganisms led to obvious color shifts, which could be observed by the naked eye. A total of 15 microorganisms had their own response patterns and were differentiated by linear discriminant analysis (LDA) successfully. Moreover, microorganism mixtures could also be well discerned. The method is simple, fast (within 5 s), effective, and visual, showing the potential applications in pathogen diagnosis and environmental monitoring.

  18. Evaluation of a Rapid Method of Determination of Plasma Fibrinogen

    Science.gov (United States)

    Thomson, G. W.; McSherry, B. J.; Valli, V. E. O.

    1974-01-01

    An evaluation was made of a rapid semiautomated method of determining fibrinogen levels in bovine plasma. This method, the fibrometer method of Morse, Panek and Menga (8), is based on the principle that when thrombin is added to suitably diluted plasma the time of clotting is linearly related to the fibrinogen concentration. A standard curve prepared using bovine plasma had an r value of .9987 and analysis of variance showed there was no significant deviation from regression. A comparison of the fibrometer method and the biuret method of Ware, Guest and Seegers done on 158 bovine plasma samples showed good correlation between the two methods. It was concluded that the fibrometer method does measure bovine fibrinogen and has considerable merit for use in clinical diseases of cattle. PMID:4277474

  19. Rapid methods for determination of fluoxetine in pharmaceutical formulations.

    Science.gov (United States)

    Mandrioli, R; Pucci, V; Visini, D; Varani, G; Raggi, M A

    2002-08-01

    Two different analytical methods for the quality control of fluoxetine in commercial formulations have been developed and compared: a spectrofluorimetric method and a capillary zone electrophoretic (CZE) method. The fluorescence emission values were measured at lambda=293 nm when exciting at lambda=230 nm. The CZE method used an uncoated fused-silica capillary and pH 2.5 phosphate buffer as the background electrolyte. The extraction of fluoxetine from the capsules consisted of a simple one-step dissolution with methanol/water, filtration and dilution. Both methods gave satisfactory results in terms of precision; the best results were obtained for the electrophoretic method, with RSD% values always lower than 2.0%. The accuracy was assessed by means of recovery studies, which gave very good results, between 97.5 and 102.6%. Furthermore, both methods also have the advantage of being very rapid.

  20. A simple and rapid method for determining transgenic cotton plants.

    Science.gov (United States)

    Zhang, Baohong; Wang, Hongmei; Liu, Fang; Wang, Qinglian

    2013-01-01

    Determining transgenic events is a critical step for obtaining transgenic plants as well as the later stage of application. Traditional methods, such as Northern blotting and qRT-PCR, for determining transgenic events either require radioactively labeled substrates, expensive instruments, or long-time commitments, which result in lab and time-consuming as well as expensive costs. These methods also require destroying the transgenic events. In this chapter, we present a simple and rapid method for determining transgenic cotton plants in both laboratory and field conditions. This method is based on the sensitivity of transgenic and non-transgenic plants to a specific chemical, such as antibiotics or herbicides. This method will facilitate the screening of transgenic events, save time, reduce cost, and speed up the application of transgenic technology on cotton breeding and production. More important, this is a nondestructive bioassay method; the transgenic plants can be transferred into greenhouse or field for the later study after the detection process.

  1. Rapid and selective method for quantitation of metronidazole in pharmaceuticals.

    Science.gov (United States)

    Sanyal, A K

    1988-01-01

    A selective and highly sensitive assay for N-1-substituted nitroimidazoles has been modified and adapted for rapid estimation of metronidazole in pharmaceuticals. The color reaction is based on diazotization of sulfanilamide with the nitrite ions liberated by alkaline hydrolysis of metronidazole and subsequent coupling of the diazonium salt with N-1-(naphthyl)-ethylenediamine dihydrochloride. This method is applicable for the assay of benzoyl metronidazole in oral suspension. Officially recommended excipients and preservatives do not interfere.

  2. Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

    Science.gov (United States)

    Gorka, Caroline A.

    2014-01-01

    A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes. PMID:24637334

  3. Rapid Enzymatic Method for Pectin Methyl Esters Determination

    Directory of Open Access Journals (Sweden)

    Lucyna Łękawska-Andrinopoulou

    2013-01-01

    Full Text Available Pectin is a natural polysaccharide used in food and pharma industries. Pectin degree of methylation is an important parameter having significant influence on pectin applications. A rapid, fully automated, kinetic flow method for determination of pectin methyl esters has been developed. The method is based on a lab-made analyzer using the reverse flow-injection/stopped flow principle. Methanol is released from pectin by pectin methylesterase in the first mixing coil. Enzyme working solution is injected further downstream and it is mixed with pectin/pectin methylesterase stream in the second mixing coil. Methanol is oxidized by alcohol oxidase releasing formaldehyde and hydrogen peroxide. This reaction is coupled to horse radish peroxidase catalyzed reaction, which gives the colored product 4-N-(p-benzoquinoneimine-antipyrine. Reaction rate is proportional to methanol concentration and it is followed using Ocean Optics USB 2000+ spectrophotometer. The analyzer is fully regulated by a lab written LabVIEW program. The detection limit was 1.47 mM with an analysis rate of 7 samples h−1. A paired t-test with results from manual method showed that the automated method results are equivalent to the manual method at the 95% confidence interval. The developed method is rapid and sustainable and it is the first application of flow analysis in pectin analysis.

  4. Cost Effective Paper-Based Colorimetric Microfluidic Devices and Mobile Phone Camera Readers for the Classroom

    Science.gov (United States)

    Koesdjojo, Myra T.; Pengpumkiat, Sumate; Wu, Yuanyuan; Boonloed, Anukul; Huynh, Daniel; Remcho, Thomas P.; Remcho, Vincent T.

    2015-01-01

    We have developed a simple and direct method to fabricate paper-based microfluidic devices that can be used for a wide range of colorimetric assay applications. With these devices, assays can be performed within minutes to allow for quantitative colorimetric analysis by use of a widely accessible iPhone camera and an RGB color reader application…

  5. Feature extraction using distribution representation for colorimetric sensor arrays used as explosives detectors

    DEFF Research Database (Denmark)

    Alstrøm, Tommy Sonne; Raich, Raviv; Kostesha, Natalie

    2012-01-01

    We present a colorimetric sensor array which is able to detect explosives such as DNT, TNT, HMX, RDX and TATP and identifying volatile organic compounds in the presence of water vapor in air. To analyze colorimetric sensors with statistical methods, a suitable representation of sensory readings...

  6. SIMS: a hybrid method for rapid conformational analysis.

    Directory of Open Access Journals (Sweden)

    Bryant Gipson

    Full Text Available Proteins are at the root of many biological functions, often performing complex tasks as the result of large changes in their structure. Describing the exact details of these conformational changes, however, remains a central challenge for computational biology due the enormous computational requirements of the problem. This has engendered the development of a rich variety of useful methods designed to answer specific questions at different levels of spatial, temporal, and energetic resolution. These methods fall largely into two classes: physically accurate, but computationally demanding methods and fast, approximate methods. We introduce here a new hybrid modeling tool, the Structured Intuitive Move Selector (sims, designed to bridge the divide between these two classes, while allowing the benefits of both to be seamlessly integrated into a single framework. This is achieved by applying a modern motion planning algorithm, borrowed from the field of robotics, in tandem with a well-established protein modeling library. sims can combine precise energy calculations with approximate or specialized conformational sampling routines to produce rapid, yet accurate, analysis of the large-scale conformational variability of protein systems. Several key advancements are shown, including the abstract use of generically defined moves (conformational sampling methods and an expansive probabilistic conformational exploration. We present three example problems that sims is applied to and demonstrate a rapid solution for each. These include the automatic determination of "active" residues for the hinge-based system Cyanovirin-N, exploring conformational changes involving long-range coordinated motion between non-sequential residues in Ribose-Binding Protein, and the rapid discovery of a transient conformational state of Maltose-Binding Protein, previously only determined by Molecular Dynamics. For all cases we provide energetic validations using well

  7. A novel method for rapid in vitro radiobioassay

    Science.gov (United States)

    Crawford, Evan Bogert

    Rapid and accurate analysis of internal human exposure to radionuclides is essential to the effective triage and treatment of citizens who have possibly been exposed to radioactive materials in the environment. The two most likely scenarios in which a large number of citizens would be exposed are the detonation of a radiation dispersal device (RDD, "dirty bomb") or the accidental release of an isotope from an industrial source such as a radioisotopic thermal generator (RTG). In the event of the release and dispersion of radioactive materials into the environment in a large city, the entire population of the city -- including all commuting workers and tourists -- would have to be rapidly tested, both to satisfy the psychological needs of the citizens who were exposed to the mental trauma of a possible radiation dose, and to satisfy the immediate medical needs of those who received the highest doses and greatest levels of internal contamination -- those who would best benefit from rapid, intensive medical care. In this research a prototype rapid screening method to screen urine samples for the presence of up to five isotopes, both individually and in a mixture, has been developed. The isotopes used to develop this method are Co-60, Sr-90, Cs-137, Pu-238, and Am-241. This method avoids time-intensive chemical separations via the preparation and counting of a single sample on multiple detectors, and analyzing the spectra for isotope-specific markers. A rapid liquid-liquid separation using an organic extractive scintillator can be used to help quantify the activity of the alpha-emitting isotopes. The method provides quantifiable results in less than five minutes for the activity of beta/gamma-emitting isotopes when present in the sample at the intervention level as defined by the Centers for Disease Control and Prevention (CDC), and quantifiable results for the activity levels of alpha-emitting isotopes present at their respective intervention levels in approximately 30

  8. MATRIX DISCRIMINANT ANALYSIS WITH APPLICATION TO COLORIMETRIC SENSOR ARRAY DATA.

    Science.gov (United States)

    Zhong, Wenxuan; Suslick, Kenneth S

    2015-09-01

    With the rapid development of nano-technology, a "colorimetric sensor array" (CSA) which is referred to as an optical electronic nose has been developed for the identification of toxicants. Unlike traditional sensors which rely on a single chemical interaction, CSA can measure multiple chemical interactions by using chemo-responsive dyes. The color changes of the chemo-responsive dyes are recorded before and after exposure to toxicants and serve as a template for classification. The color changes are digitalized in the form of a matrix with rows representing dye effects and columns representing the spectrum of colors. Thus, matrix-classification methods are highly desirable. In this article, we develop a novel classification method, matrix discriminant analysis (MDA), which is a generalization of linear discriminant analysis (LDA) for the data in matrix form. By incorporating the intrinsic matrix-structure of the data in discriminant analysis, the proposed method can improve CSA's sensitivity and more importantly, specificity. A penalized MDA method, PMDA, is also introduced to further incorporate sparsity structure in discriminant function. Numerical studies suggest that the proposed MDA and PMDA methods outperform LDA and other competing discriminant methods for matrix predictors. The asymptotic consistency of MDA is also established. R code and data are available online as supplementary material.

  9. Smartphone spectrometer for colorimetric biosensing.

    Science.gov (United States)

    Wang, Yi; Liu, Xiaohu; Chen, Peng; Tran, Nhung Thi; Zhang, Jinling; Chia, Wei Sheng; Boujday, Souhir; Liedberg, Bo

    2016-05-23

    We report on a smartphone spectrometer for colorimetric biosensing applications. The spectrometer relies on a sample cell with an integrated grating substrate, and the smartphone's built-in light-emitting diode flash and camera. The feasibility of the smartphone spectrometer is demonstrated for detection of glucose and human cardiac troponin I, the latter in conjunction with peptide-functionalized gold nanoparticles.

  10. Rapid assessment methods in eye care: An overview

    Directory of Open Access Journals (Sweden)

    Srinivas Marmamula

    2012-01-01

    Full Text Available Reliable information is required for the planning and management of eye care services. While classical research methods provide reliable estimates, they are prohibitively expensive and resource intensive. Rapid assessment (RA methods are indispensable tools in situations where data are needed quickly and where time- or cost-related factors prohibit the use of classical epidemiological surveys. These methods have been developed and field tested, and can be applied across almost the entire gamut of health care. The 1990s witnessed the emergence of RA methods in eye care for cataract, onchocerciasis, and trachoma and, more recently, the main causes of avoidable blindness and visual impairment. The important features of RA methods include the use of local resources, simplified sampling methodology, and a simple examination protocol/data collection method that can be performed by locally available personnel. The analysis is quick and easy to interpret. The entire process is inexpensive, so the survey may be repeated once every 5-10 years to assess the changing trends in disease burden. RA survey methods are typically linked with an intervention. This article provides an overview of the RA methods commonly used in eye care, and emphasizes the selection of appropriate methods based on the local need and context.

  11. A Colorimetric Bioassay for Perchlorate

    Science.gov (United States)

    Heinnickel, M. L.; Smith, S.; Coates, J. D.

    2007-12-01

    Recognition of perchlorate (ClO4-) as a widespread contaminant across the United States and its potential adverse affects towards human health has motivated the EPA to place ClO4- on its contaminant candidate list for drinking water supplies. While a federal MCL has not yet been set, a recommended public health goal of 1 ppb (μg.L-1) was established by the US EPA in 2002. To date, methods of detection require use of sensitive ion chromatographic equipment that are expensive, time consuming, and require highly trained personnel for use. Our studies are focused on the development of a highly sensitive, simple, and robust colorimetric bioassay based on the primary enzyme involved in microbial ClO4- reduction, the perchlorate reductase (Pcr). A previously published assay used reduced methyl viologen (MV, the dye is reduced with sodium hydrosulfite) as an electron donor to demonstrate Pcr activity. The assay directly correlates the amount of MV oxidized with the amount of ClO4- reduced by assuming a transfer of four electrons. To test this assumption, we compared actual concentrations of MV oxidized to ClO4- reduced in this assay. ClO4- concentrations were determined using a Dionex ICS-500 ion chromatography system, while MV concentrations were determined using a standard curve generated at 578 nm. Comparisons between the two revealed that twelve molecules of MV were oxidized for each molecule of ClO4- reduced. The oxidation of these additional eight MV molecules is explained by the interaction of the dye with chlorite (the product of the Pcr reaction) and other contaminants that could be present in the enzyme prep. This unsettling result indicated this assay would be problematic for the detection of ClO4- in soil, which has many chemicals that could react with MV. To improve upon this assay, we have tried to reduce ClO4- using less reactive dyes and reductants. The reductants ascorbic acid, NADH, and dithiothreitol drive Pcr catalyzed ClO4- reduction, however, they

  12. A rapid DNA extraction method suitable for human papillomavirus detection.

    Science.gov (United States)

    Brestovac, Brian; Wong, Michelle E; Costantino, Paul S; Groth, David

    2014-04-01

    Infection with oncogenic human papillomavirus (HPV) genotypes is necessary for the development of cervical cancer. Testing for HPV DNA from liquid based cervical samples can be used as an adjunct to traditional cytological screening. In addition there are ongoing viral load, genotyping, and prevalence studies. Therefore, a sensitive DNA extraction method is needed to maximize the efficiency of HPV DNA detection. The XytXtract Tissue kit is a DNA extraction kit that is rapid and so could be useful for HPV testing, particularly in screening protocols. This study was undertaken to determine the suitability of this method for HPV detection. DNA extraction from HeLa and Caski cell lines containing HPV 18 and 16 respectively together with DNA from five liquid based cervical samples were used in a HPV PCR assay. DNA was also extracted using the QIAamp DNA mini kit (Qiagen, Hilden, Germany) as a comparison. DNA extracts were serially diluted and assayed. HPV DNA was successfully detected in cell lines and cervical samples using the XytXtract Tissue kit. In addition, the XytXtract method was found to be more sensitive than the QIAmp method as determined by a dilution series of the extracted DNA. While the XytXtract method is a closed, the QIAamp method uses a spin column with possible loss of DNA through DNA binding competition of the matrix, which could impact on the final extraction efficiency. The XytXtract is a cheap, rapid and efficient method for extracting HPV DNA from both cell lines and liquid based cervical samples. © 2014 Wiley Periodicals, Inc.

  13. Radiometric method for the rapid detection of Leptospira organisms

    Energy Technology Data Exchange (ETDEWEB)

    Manca, N.; Verardi, R.; Colombrita, D.; Ravizzola, G.; Savoldi, E.; Turano, A.

    1986-02-01

    A rapid and sensitive radiometric method for detection of Leptospira interrogans serovar pomona and Leptospira interrogans serovar copenhageni is described. Stuart's medium and Middlebrook TB (12A) medium supplemented with bovine serum albumin, catalase, and casein hydrolysate and labeled with /sup 14/C-fatty acids were used. The radioactivity was measured in a BACTEC 460. With this system, Leptospira organisms were detected in human blood in 2 to 5 days, a notably shorter time period than that required for the majority of detection techniques.

  14. Method for rapidly determining a pulp kappa number using spectrophotometry

    Science.gov (United States)

    Chai, Xin-Sheng; Zhu, Jun Yong

    2002-01-01

    A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO.sub.2). Consequently, spectral interference from the precipitated MnO.sub.2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.

  15. Rapid coulometric method for the Kjeldahl determination of nitrogen.

    Science.gov (United States)

    Boström, C A; Cedergren, A; Johansson, G; Pettersson, I

    1974-11-01

    A rapid coulometric method for the Kjeldahl determination of nitrogen is described. The samples are digested by means of the Tecator AB digestion system which permits forty samples to be digested at the same time. The digestion products are diluted to 75 ml and 1 ml is coulometrically titrated in 1-2 min: 20-30 determinations can be performed per hour. For substances containing nitrogen in the per cent range the relative standard deviations for eight different substances were 0.1-1%.

  16. A Novel Rapid Method to Determine Cannabis Seed Germination Ability

    OpenAIRE

    吉澤, 政夫; 荒金, 眞佐子; 鈴木, 幸子; 北川, 重美; 中嶋, 順一; 森, 謙一郎; 荻野, 周三; Masao, Yoshizawa; Masako, Aragane; Yukiko, Suzuki; Shigemi, Kitagawa; Jun'ichi, Nakajima; Ken'ichiro, Mori; Shuzo, Ogino; 東京都健康安全研究センター薬用植物園

    2011-01-01

    A novel rapid method to determine cannabis seed germination ability was developed. Cannabis seeds were soaked in water for 15 minutes at 40℃, and germs were removed from the seeds by cracking the shell with tweezers. The germs were soaked in water for 15 minutes at 40℃, and the swollen skin was peeled off. The peeled germs were again soaked in water for 10 minutes at 40℃, and the angles between the seed leaves were measured. Cannabis seeds with angles of the seed leaves exceeding 30 degrees w...

  17. Colorimetric Detection of Norovirus in Oysters Samples through DNAzyme as Signaling Probe.

    Science.gov (United States)

    Batule, Bhagwan Sahebrao; Kim, Seong U; Mun, Hyoyoung; Choi, Changsun; Shim, Won-Bo; Kim, Min-Gon

    2018-01-30

    Worldwide, norovirus (NV) is one of the most associated cause of acute gastroenteritis, which leads nearly 50,000 child deaths every year in developing countries. Therefore, there is great demand to develop rapid, low-cost, and accurate detection assay for the foodborne norovirus infection in order to reduce mortality caused by norovirus. Considering importance of norovirus, we have demonstrated a highly sensitive and specific colorimetric detection method for analysis of human norovirus genogroups I and II (HuNoV GI and II) in oyster samples. This is the first report to employing colorimetric HRPzyme-integrated PCR for direct norovirus detection from the real shellfish samples. We found that the HRPzyme-integrated PCR method is more sensitive than gel-electrophoresis approach and could detect HuNoV GI and II genome upto one copy per milliliter. The specificity of the proposed method was successfully demonstrated for HuNoV GI and II. Further, we performed testing HuNoVs in the spiked oyster samples and the HRPzyme-integrated PCR method proved to be an ultrasensitive and selective method for detecting HuNoVs in the real samples. By integrating the proposed method with the portable PCR machine, it would be more reliable to improve food safety by detecting HuNoVs in the different types of shellfish such as oyster and mussel at the production field.

  18. Simple colorimetric detection of doxycycline and oxytetracycline using unmodified gold nanoparticles

    Science.gov (United States)

    Li, Jie; Fan, Shumin; Li, Zhigang; Xie, Yuanzhe; Wang, Rui; Ge, Baoyu; Wu, Jing; Wang, Ruiyong

    2014-08-01

    The interaction between tetracycline antibiotics and gold nanoparticles was studied. With citrate-coated gold nanoparticles as colorimetric probe, a simple and rapid detection method for doxycycline and oxytetracycline has been developed. This method relies on the distance-dependent optical properties of gold nanoparticles. In weakly acidic buffer medium, doxycycline and oxytetracycline could rapidly induce the aggregation of gold nanoparticles, resulting in red-to-blue (or purple) colour change. The experimental parameters were optimized with regard to pH, the concentration of the gold nanoparticles and the reaction time. Under optimal experimental conditions, the linear range of the colorimetric sensor for doxycycline/oxytetracycline was 0.06-0.66 and 0.59-8.85 μg mL-1, respectively. The corresponding limit of detection for doxycycline and oxytetracycline was 0.0086 and 0.0838 μg mL-1, respectively. This assay was sensitive, selective, simple and readily used to detect tetracycline antibiotics in food products.

  19. Selective spectrophotometric determination of TNT using a dicyclohexylamine-based colorimetric sensor.

    Science.gov (United States)

    Erçağ, Erol; Uzer, Ayşem; Apak, Reşat

    2009-05-15

    Because of the extremely heterogeneous distribution of explosives in contaminated soils, on-site colorimetric methods are efficient tools to assess the nature and extent of contamination. To meet the need for rapid and low-cost chemical sensing of explosive traces or residues in soil and post-blast debris, a colorimetric absorption-based sensor for trinitrotoluene (TNT) determination has been developed. The charge-transfer (CT) reagent (dicyclohexylamine, DCHA) is entrapped in a polyvinylchloride (PVC) polymer matrix plasticised with dioctylphtalate (DOP), and moulded into a transparent sensor membrane sliced into test strips capable of sensing TNT showing an absorption maximum at 530 nm when placed in a 1-mm spectrophotometer cell. The sensor gave a linear absorption response to 5-50 mg L(-1) TNT solutions in 30% aqueous acetone with limit of detection (LOD): 3 mg L(-1). The sensor is only affected by tetryl, but not by RDX, pentaerythritoltetranitrate (PETN), dinitrotoluene (DNT), and picric acid. The proposed method was statistically validated for TNT assay against high performance liquid chromatography (HPLC) using a standard sample of Comp B. The developed sensor was relatively resistant to air and water, was of low-cost and high specificity, gave a rapid and reproducible response, and was suitable for field use of TNT determination in both dry and humid soil and groundwater with a portable colorimeter.

  20. RAPID SEPARATION METHOD FOR EMERGENCY WATER AND URINE SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Culligan, B.

    2008-08-27

    The Savannah River Site Environmental Bioassay Lab participated in the 2008 NRIP Emergency Response program administered by the National Institute for Standards and Technology (NIST) in May, 2008. A new rapid column separation method was used for analysis of actinides and {sup 90}Sr the NRIP 2008 emergency water and urine samples. Significant method improvements were applied to reduce analytical times. As a result, much faster analysis times were achieved, less than 3 hours for determination of {sup 90}Sr and 3-4 hours for actinides. This represents a 25%-33% improvement in analysis times from NRIP 2007 and a {approx}100% improvement compared to NRIP 2006 report times. Column flow rates were increased by a factor of two, with no significant adverse impact on the method performance. Larger sample aliquots, shorter count times, faster cerium fluoride microprecipitation and streamlined calcium phosphate precipitation were also employed. Based on initial feedback from NIST, the SRS Environmental Bioassay Lab had the most rapid analysis times for actinides and {sup 90}Sr analyses for NRIP 2008 emergency urine samples. High levels of potential matrix interferences may be present in emergency samples and rugged methods are essential. Extremely high levels of {sup 210}Po were found to have an adverse effect on the uranium results for the NRIP-08 urine samples, while uranium results for NRIP-08 water samples were not affected. This problem, which was not observed for NRIP-06 or NRIP-07 urine samples, was resolved by using an enhanced {sup 210}Po removal step, which will be described.

  1. A method for rapid similarity analysis of RNA secondary structures

    Directory of Open Access Journals (Sweden)

    Liu Na

    2006-11-01

    Full Text Available Abstract Background Owing to the rapid expansion of RNA structure databases in recent years, efficient methods for structure comparison are in demand for function prediction and evolutionary analysis. Usually, the similarity of RNA secondary structures is evaluated based on tree models and dynamic programming algorithms. We present here a new method for the similarity analysis of RNA secondary structures. Results Three sets of real data have been used as input for the example applications. Set I includes the structures from 5S rRNAs. Set II includes the secondary structures from RNase P and RNase MRP. Set III includes the structures from 16S rRNAs. Reasonable phylogenetic trees are derived for these three sets of data by using our method. Moreover, our program runs faster as compared to some existing ones. Conclusion The famous Lempel-Ziv algorithm can efficiently extract the information on repeated patterns encoded in RNA secondary structures and makes our method an alternative to analyze the similarity of RNA secondary structures. This method will also be useful to researchers who are interested in evolutionary analysis.

  2. Colorimetric determination of in vitro feed protein degradation

    African Journals Online (AJOL)

    A colorimetric method for determining protein degradation us' ing a diazonium chromophore was compared with the dacron bag technique. Diazotized f ish meal, maize gluten meal and soya-bean were incubated with strained rumen fluid and a suitable growth medium. Only 49o/o and 18% of the colour bound to soya-bean ...

  3. Rapid identification of cytokinins by an immunological method

    Energy Technology Data Exchange (ETDEWEB)

    Morris, R.O.; Jameson, P.E.; Morris, J.W. (Univ. of Missouri-Columbia (USA)); Laloue, M. (Centre Nationale de la Recherche Scientifique, Gif-sur-Yvette (France))

    1991-04-01

    A method for rapid identification of bacterial cytokinins has been developed in which cultures are fed ({sup 3}H)adenine, the cytokinins (including, {sup 3}H-labeled cytokinins) are isolated by immunoaffinity chromatography, and analyzed by HPLC with on-line scintillation counting. Analysis of Agrobacterium tumefaciens strains showed that some produced primarily trans-zeatin, whereas others produced primarily trans-zeatin riboside. Pseudomonas syringae pv savastanoi produced mixtures of transzeatin, dihydrozeatin, 1{double prime}-methyl-trans-zeatin riboside, and other unknown cytokinin-like substances. Corynebacterium fascians, produced cis-zeatin, isopentenyladenine and isopentenyladenosine. The technique is designed for qualitative rather than quantitative studies and allows ready identification of bacterial cytokinins. It may also have utility in the study of plant cytokinins if adequate incorporation of label into cytokinin precursor pools can be achieved.

  4. A rapid protection switching method in carrier ethernet ring networks

    Science.gov (United States)

    Yuan, Liang; Ji, Meng

    2008-11-01

    Abstract: Ethernet is the most important Local Area Network (LAN) technology since more than 90% data traffic in access layer is carried on Ethernet. From 10M to 10G, the improving Ethernet technology can be not only used in LAN, but also a good choice for MAN even WAN. MAN are always constructed in ring topology because the ring network could provide resilient path protection by using less resource (fibre or cable) than other network topologies. In layer 2 data networks, spanning tree protocol (STP) is always used to protect transmit link and preventing the formation of logic loop in networks. However, STP cannot guarantee the efficiency of service convergence when link fault happened. In fact, convergent time of networks with STP is about several minutes. Though Rapid Spanning Tree Protocol (RSTP) and Multi-Spanning Tree Protocol (MSTP) improve the STP technology, they still need a couple of seconds to achieve convergence, and can not provide sub-50ms protection switching. This paper presents a novel rapid ring protection method (RRPM) for carrier Ethernet. Unlike other link-fault detection method, it adopts distributed algorithm to detect link fault rapidly (sub-50ms). When networks restore from link fault, it can revert to the original working state. RRPM can provide single ring protection and interconnected ring protection without the formation of super loop. In normal operation, the master node blocks the secondary port for all non-RRPM Ethernet frames belonging to the given RRPM Ring, thereby avoiding a loop in the ring. When link fault happens, the node on which the failure happens moves from the "ring normal" state to the "ring fault" state. It also sends "link down" frame immediately to other nodes and blocks broken port and flushes its forwarding database. Those who receive "link down" frame will flush forwarding database and master node should unblock its secondary port. When the failure restores, the whole ring will revert to the normal state. That is

  5. A colorimetric detection of acrylamide in potato chips based on nucleophile-initiated thiol-ene Michael addition.

    Science.gov (United States)

    Hu, Qinqin; Fu, Yingchun; Xu, Xiahong; Qiao, Zhaohui; Wang, Ronghui; Zhang, Ying; Li, Yanbin

    2016-02-07

    Acrylamide (AA), a neurotoxin and a potential carcinogen, has been found in various thermally processed foods such as potato chips, biscuits, and coffee. Simple, cost-effective, and sensitive methods for the rapid detection of AA are needed to ensure food safety. Herein, a novel colorimetric method was proposed for the visual detection of AA based on a nucleophile-initiated thiol-ene Michael addition reaction. Gold nanoparticles (AuNPs) were aggregated by glutathione (GSH) because of a ligand-replacement, accompanied by a color change from red to purple. In the presence of AA, after the thiol-ene Michael addition reaction between GSH and AA with the catalysis of a nucleophile, the sulfhydryl group of GSH was consumed by AA, which hindered the subsequent ligand-replacement and the aggregation of AuNPs. Therefore, the concentration of AA could be determined by the visible color change caused by dispersion/aggregation of AuNPs. This new method showed high sensitivity with a linear range from 0.1 μmol L(-1) to 80 μmol L(-1) and a detection limit of 28.6 nmol L(-1), and especially revealed better selectivity than the fluorescence sensing method reported previously. Moreover, this new method was used to detect AA in potato chips with a satisfactory result in comparison with the standard methods based on chromatography, which indicated that the colorimetric method can be expanded for the rapid detection of AA in thermally processed foods.

  6. Method for Rapid Protein Identification in a Large Database

    Directory of Open Access Journals (Sweden)

    Wenli Zhang

    2013-01-01

    Full Text Available Protein identification is an integral part of proteomics research. The available tools to identify proteins in tandem mass spectrometry experiments are not optimized to face current challenges in terms of identification scale and speed owing to the exponential growth of the protein database and the accelerated generation of mass spectrometry data, as well as the demand for nonspecific digestion and post-modifications in complex-sample identification. As a result, a rapid method is required to mitigate such complexity and computation challenges. This paper thus aims to present an open method to prevent enzyme and modification specificity on a large database. This paper designed and developed a distributed program to facilitate application to computer resources. With this optimization, nearly linear speedup and real-time support are achieved on a large database with nonspecific digestion, thus enabling testing with two classical large protein databases in a 20-blade cluster. This work aids in the discovery of more significant biological results, such as modification sites, and enables the identification of more complex samples, such as metaproteomics samples.

  7. Development and validation of a colorimetric sensor array for fish spoilage monitoring

    DEFF Research Database (Denmark)

    Morsy, Mohamed K.; Zor, Kinga; Kostesha, Natalie

    2016-01-01

    Given the need for non-destructive methods and sensors for food spoilage monitoring, we have evaluated sixteen chemo-sensitive compounds incorporated in an array for colorimetric detection of typical spoilage compounds (trimethylamine, dimethylamine, cadaverine, putrescine) and characterized...

  8. Colorimetric determination of melamine in milk using unmodified silver nanoparticles

    Science.gov (United States)

    Kumar, Naveen; Kumar, Harish; Mann, Bimlesh; Seth, Raman

    2016-03-01

    Melamine is nitrogen rich chemical compound used as an adulterant in dairy products by unscrupulous people to increase the apparent protein content. This incident prompted the researchers to develop simple methods for easy detection of melamine in food samples. In the present paper, we report a simple and sensitive colorimetric method for detection of melamine in milk based on silver nanoparticles. This method relies upon the principle that melamine causes the aggregation of silver nanoparticles, resulting in abrupt color change from yellow to red under optimized conditions. The concentration of melamine in adulterated sample can be quantitated by monitoring the absorption spectra of silver nanoparticles using ultraviolet-visible (UV-Vis) spectrometer. The present colorimetric method which utilizes silver nanoparticles of 35 nm can reliably detect melamine down to a concentration of 0.04 mg l- 1.

  9. RAPID TEST METHOD FOR EVALUATION OF ANTIFREEZE ADDITIVE EFFICIENCY

    Directory of Open Access Journals (Sweden)

    S. V. Gushchin

    2015-01-01

    Full Text Available Usage of chemical additives while executing concrete works at negative temperatures is considered as a convenient and economical method. Range of the used antifreeze additives is rather wide. A great number of new additives are advertised but their characteristics have not been practically studied. Evaluation of the antifreeze additive efficiency is unfortunately rather long process and it does not provide comprehensive data on concrete structure formation processes. Due to this development of rapid and comprehensive methodology for construction companies is urgently required.Freezing processes of antifreeze additive aqueous solutions and hardening of cement paste with them have been investigated in the paper. The paper proposes a methodology for determination of freezing point for aqueous solutions of chemical additives of various applications. Identity of  freezing point for a chemical additive aqueous solution and cement paste with an equal concentration of the additive in the paste pore fluid has been determined while taking  calcium nitrate and sodium formate additives as an example. The paper demonstrates the possibility to evaluate efficiency of antifreeze additive action on the basis of kinetics in temperature changes of the cement paste with additives by its consecutive freezing and defrosting.  A methodology for operational evaluation in the field of chemical additive application for concreting items at negative temperatures has been offered in the paper.  The methodology does not require  deficient and expensive test-equipment. It can be applied at ordinary construction companies and it is comprehensible for personnel of low-qualification.  The paper shows the possibility to develop an original methodology for designing concrete structure which is based on operating efficiency determinations  for single and integrated antifreeze additives.

  10. A new rapid method for rockfall energies and distances estimation

    Science.gov (United States)

    Giacomini, Anna; Ferrari, Federica; Thoeni, Klaus; Lambert, Cedric

    2016-04-01

    and distances at the base to block and slope features. The validation of the proposed approach was conducted by comparing predictions to experimental data collected in the field and gathered from the scientific literature. The method can be used for both natural and constructed slopes and easily extended to more complicated and articulated slope geometries. The study shows its great potential for a quick qualitative hazard assessment providing indication about impact energy and horizontal distance of the first impact at the base of a rock cliff. Nevertheless, its application cannot substitute a more detailed quantitative analysis required for site-specific design of mitigation measures. Acknowledgements The authors gratefully acknowledge the financial support of the Australian Coal Association Research Program (ACARP). References Dorren, L.K.A. (2003) A review of rockfall mechanics and modelling approaches, Progress in Physical Geography 27(1), 69-87. Agliardi, F., Crosta, G.B., Frattini, P. (2009) Integrating rockfall risk assessment and countermeasure design by 3D modelling techniques. Natural Hazards and Earth System Sciences 9(4), 1059-1073. Ferrari, F., Thoeni, K., Giacomini, A., Lambert, C. (2016) A rapid approach to estimate the rockfall energies and distances at the base of rock cliffs. Georisk, DOI: 10.1080/17499518.2016.1139729.

  11. A Simple Assay for Ultrasensitive Colorimetric Detection of Ag+ at Picomolar Levels Using Platinum Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yi-Wei Wang

    2017-11-01

    Full Text Available In this work, uniformly-dispersed platinum nanoparticles (PtNPs were synthesized by a simple chemical reduction method, in which citric acid and sodium borohydride acted as a stabilizer and reducer, respectively. An ultrasensitive colorimetric sensor for the facile and rapid detection of Ag+ ions was constructed based on the peroxidase mimetic activities of the obtained PtNPs, which can catalyze the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB by H2O2 to produce colored products. The introduced Ag+ would be reduced to Ag0 by the capped citric acid, and the deposition of Ag0 on the PtNPs surface, can effectively inhibit the peroxidase-mimetic activity of PtNPs. Through measuring the maximum absorption signal of oxidized TMB at 652 nm, ultra-low detection limits (7.8 pM of Ag+ can be reached. In addition to such high sensitivity, the colorimetric assay also displays excellent selectivity for other ions of interest and shows great potential for the detection of Ag+ in real water samples.

  12. Digital colorimetric determination of vitamin C using 18-molybdo-2-phosphate

    Directory of Open Access Journals (Sweden)

    Galyna O. Petrushyna

    2016-12-01

    Full Text Available Reduction with ascorbic acid of tetraethylammonium salt of 18-molybdo-2-phosphate heteropoly complex impregnated on the filter or the chromatographic paper was investigated. Digital scan images of colored paper test strips obtained with the office scanner were resolved into R, G, and B colors. It was found that dependence of the coordinates of RGB colors on the ascorbic acid concentration is satisfactorily linearized using the equation y = yo + Aexp(–c/t. Rapid and simple colorimetric method for the determination of ascorbic acid based on its reaction with impregnated on the paper 18-MPC was developed. Method was applied to the determination of vitamin C in juices.

  13. Rapid Methods for detection of Veterinary Drug residues in Meat

    Directory of Open Access Journals (Sweden)

    Chandan

    2010-10-01

    methodologies, the variety of residues to search per sample and the need to invest on powerful new instruments for identification and confirmatory purposes. Rapid and versatile screening methodologies make its control easier and reduce the number of non-compliant samples to be confirmed through tedious and costly confirmatory analytical methodologies. For instance, the multiresidue analysis can be performed better by using fast LC methods. Thus, the availability of new screening methodologies and the improvement of the existing ones will contribute to a better safety assurance of meat and other foods of animal origin. [Vet. World 2010; 3(5.000: 241-246

  14. Development of a colorimetric sensor array for squid spoilage assessment.

    Science.gov (United States)

    Zaragozá, Patricia; Fuentes, Ana; Ruiz-Rico, María; Vivancos, José-Luis; Fernández-Segovia, Isabel; Ros-Lis, José V; Barat, José M; Martínez-Máñez, Ramón

    2015-05-15

    The aim of this work was to develop and evaluate a rapid, easy-to-use optoelectronic system for the shelf-life assessment of squid in cold storage. For this purpose, an optoelectronic nose was designed, which consisted of an array containing six sensing materials prepared by combining different dyes and two inorganic supports (aluminium oxide and silica gel). Samples were packaged with the colorimetric array and kept in cold storage for 12 days. Squid spoilage was monitored simultaneously by the colorimetric array and by the physico-chemical and microbial analyses during storage. Samples exceeded the acceptability limits for microbial counts on the third day. PCA analysis carried out with CIELab showed that the colorimetric array was able to discriminate between fresh squid fit for consumption and spoiled squid. The statistical models obtained by PLS, with the optoelectronic nose, successfully predicted CO2 and O2 content in the headspace as well as microbial growth. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Rapid method for identification of transgenic fish zygosity

    Directory of Open Access Journals (Sweden)

    . Alimuddin

    2007-07-01

    Full Text Available Identification of zygosity in transgenik fish is normally achieved by PCR analysis with genomic DNA template extracted from the tissue of progenies which are derived by mating the transgenic fish and wild-type counterpart.  This method needs relatively large amounts of fish material and is time- and labor-intensive. New approaches addressing this problem could be of great help for fish biotechnologists.  In this experiment, we applied a quantitative real-time PCR (qr-PCR method to analyze zygosity in a stable line of transgenic zebrafish (Danio rerio carrying masu salmon, Oncorhynchus masou D6-desaturase-like gene. The qr-PCR was performed using iQ SYBR Green Supermix in the iCycler iQ Real-time PCR Detection System (Bio-Rad Laboratories, USA.  Data were analyzed using the comparative cycle threshold method.  The results demonstrated a clear-cut identification of all transgenic fish (n=20 classified as a homozygous or heterozygous.  Mating of those fish with wild-type had revealed transgene transmission to the offspring following expected Mendelian laws. Thus, we found that the qTR-PCR to be effective for a rapid and precise determination of zygosity in transgenic fish. This technique could be useful in the establishment of breeding programs for mass transgenic fish production and in experiments in which zygosity effect could have a functional impact. Keywords: quantitative real-time PCR; zygosity; transgenic fish; mass production   ABSTRAK Identifikasi sigositas ikan transgenik biasanya dilakukan menggunakan analisa PCR dengan cetakan DNA genomik yang diekstraksi dari jaringan ikan hasil persilangan antara ikan transgenik dan ikan normal.   Metode ini memerlukan ikan dalam jumlah yang banyak, dan juga waktu serta tenaga.  Pendekatan baru untuk mengatasi masalah tersebut akan memberikan manfaat besar kepada peneliti bioteknologi perikanan.  Pada penelitian ini, kami menggunakan metode PCR real-time kuantitatif (krt-PCR untuk

  16. A rapid cloning method employing orthogonal end protection

    NARCIS (Netherlands)

    Jakobi, A.J.|info:eu-repo/dai/nl/311489621; Huizinga, E.G.|info:eu-repo/dai/nl/12314969X

    2012-01-01

    We describe a novel in vitro cloning strategy that combines standard tools in molecular biology with a basic protecting group concept to create a versatile framework for the rapid and seamless assembly of modular DNA building blocks into functional open reading frames. Analogous to chemical

  17. [Development of MTS/pms colorimetric assay in the proliferation of leukemic cells].

    Science.gov (United States)

    Chen, Xiu-Sheng; Fang, Tie-Lan; Cai, Rui-Bo; Guo, Gui-Lan

    2002-10-01

    In order to establish a new more rapid, safe and sensitive colorimetric assay for the proliferation of leukemic cells, MTS/pms has been developed. This automated colorimetric assay is based on the characteristic of viable and metabolically active leukemic cells to cleave MTS/pms into a water-soluble product whose optical density is determined at 492 nm by an automated microtiter-plate reader photometer. The results indicated that only active leukemic cells cleaved MTS/pms into product measured, and dead cells did not reduce MTS/pms. A linear relations hip were found between the viable cell number and optical density of MTS/pms cleaved by HL-60 and K562 cell (r = 0.963). Compared with MTT and INT assays, the reduced product of MTS/pms is water-soluble. It is concluded that MTS/pms colorimetric assay is more rapid, accurate and sensitive for the bioassay of proliferation of leukemic cells.

  18. Colorimetric characterization of LCD based on constrained least squares

    Science.gov (United States)

    LI, Tong; Xie, Kai; Wang, Qiaojie; Yao, Luyang

    2017-01-01

    In order to improve the accuracy of colorimetric characterization of liquid crystal display, tone matrix model in color management modeling of display characterization is established by using constrained least squares for quadratic polynomial fitting, and find the relationship between the RGB color space to CIEXYZ color space; 51 sets of training samples were collected to solve the parameters, and the accuracy of color space mapping model was verified by 100 groups of random verification samples. The experimental results showed that, with the constrained least square method, the accuracy of color mapping was high, the maximum color difference of this model is 3.8895, the average color difference is 1.6689, which prove that the method has better optimization effect on the colorimetric characterization of liquid crystal display.

  19. Rapid Radiochemical Method for Americium-241 in Building ...

    Science.gov (United States)

    Technical Fact Sheet Analysis Purpose: Qualitative analysis Technique: Alpha spectrometry Method Developed for: Americium-241 in building materials Method Selected for: SAM lists this method for qualitative analysis of americium-241 in concrete or brick building materials. Summary of subject analytical method which will be posted to the SAM website to allow access to the method.

  20. Rapid Radiochemical Method for Radium-226 in Building ...

    Science.gov (United States)

    Technical Fact Sheet Analysis Purpose: Qualitative analysis Technique: Alpha spectrometry Method Developed for: Radium-226 in building materials Method Selected for: SAM lists this method for qualitative analysis of radium-226 in concrete or brick building materials Summary of subject analytical method which will be posted to the SAM website to allow access to the method.

  1. Detection of Carbendazim Residues with a Colorimetric Sensor Based on Gold Nanoparticles

    Science.gov (United States)

    Ma, Y.; Jiang, H.; Shen, C.; Hou, Ch.; Huo, D.; Wu, H.; Yang, M.

    2017-07-01

    Carbendazim is among the most popular benzimidazole bactericides that are widely used to boost food production, and its residue poses a great threat to human health and the environment. In this paper, we presented a colorimetric sensor based on gold nanoparticles (Au-NPs) for the detection of carbendazim residues. The Au-NPs were stabilized by citric acid synthesized by chloroauric acid and sodium citrate with a diameter of about 13 nm. Upon reaction with carbendazim, the sensor gave a clear color change that could be distinguished with the naked eye. Thus we elaborated a new method for rapid determination of this benzimidazole bactericide. After optimization of the detection conditions, the sensor showed a very good linear relationship with the carbendazim concentrations varying from 10 to 600 ppb with a detection limit down to 3.4 ppb (S/N = 3). These preliminary results demonstrate that the presented sensor is promising for fast carbendazim analysis.

  2. Rapid method for plutonium-241 determination in soil samples

    OpenAIRE

    Piekarz, M.; Komosa, A.

    2014-01-01

    A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied to soil samples contaminated with Chernobyl fallout.

  3. Notes toward a verifiable vector algebraic basis for colorimetric modeling

    OpenAIRE

    Oulton, David P.

    2009-01-01

    The presented notes aim toward improved models of the scalar visual response to flat-field stimuli, and are prompted by unease over the complexity of existing colour difference models. Some of the basic assumptions of colorimetry are examined in detail, and analytical methods whereby these assumptions can be investigated experimentally are presented. A key finding is that the standard CIE colorimetric model is verifiably correct as a predictor of point colour identity and metameric visual equ...

  4. Comparison of colorimetric and membrane introduction mass spectrometry techniques for chloramine analysis.

    Science.gov (United States)

    Lee, Wontae; Westerhoff, Paul; Yang, Xin; Shang, Chii

    2007-07-01

    Three methods for the determination of chloramines in water were compared using pH-buffered nanopure water and natural organic matter (NOM) solutions. We investigated whether the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method and/or an adapted indophenol method (Hach MonochlorF) are suitable for determining the concentration of monochloramine in drinking water. Membrane introduction mass spectrometry (MIMS) was used as a reference analysis method to determine the different chloramine species in water. All methods measured monochloramine accurately in Nanopure water, but the DPD colorimetric method measured higher residuals (inorganic and organic chloramines) than MonochlorF or MIMS when in the presence of NOM due to organic chloramines. The indophenol method (MonochlorF) accurately detected only monochloramine and not other chloramine forms. Overall, the monochloramine concentration measured by MonochlorF was comparable with the MIMS results. A combined chlorine residual approach by the DPD colorimetric method does not differentiate between monochloramine and organic chloramines. Therefore, DPD colorimetric methods can overestimate disinfection efficacy in chloraminated water systems because of interference from organic chloramines that have no or poor bactericidal ability. Compared with the DPD colorimetric method, MonochlorF is a better choice for chloraminated water systems.

  5. A rapid, small-scale sedimentation method to predict breadmaking quality of hard winter wheat

    Science.gov (United States)

    Breeders and processors are always looking for rapid and accurate methods to evaluate wheat quality. A rapid small-scale hybrid sedimentation method was developed for predicting breadmaking quality of breeders samples by combining the sodium dodecyl-sulfate (SDS) sedimentation method (AACC 56-70) an...

  6. A rapid method to estimate Westergren sedimentation rates

    Science.gov (United States)

    Alexy, Tamas; Pais, Eszter; Meiselman, Herbert J.

    2009-01-01

    The erythrocyte sedimentation rate (ESR) is a nonspecific but simple and inexpensive test that was introduced into medical practice in 1897. Although it is commonly utilized in the diagnosis and follow-up of various clinical conditions, ESR has several limitations including the required 60 min settling time for the test. Herein we introduce a novel use for a commercially available computerized tube viscometer that allows the accurate prediction of human Westergren ESR rates in as little as 4 min. Owing to an initial pressure gradient, blood moves between two vertical tubes through a horizontal small-bore tube and the top of the red blood cell (RBC) column in each vertical tube is monitored continuously with an accuracy of 0.083 mm. Using data from the final minute of a blood viscosity measurement, a sedimentation index (SI) was calculated and correlated with results from the conventional Westergren ESR test. To date, samples from 119 human subjects have been studied and our results indicate a strong correlation between SI and ESR values (R2=0.92). In addition, we found a close association between SI and RBC aggregation indices as determined by an automated RBC aggregometer (R2=0.71). Determining SI on human blood is rapid, requires no special training and has minimal biohazard risk, thus allowing physicians to rapidly screen for individuals with elevated ESR and to monitor therapeutic responses. PMID:19791973

  7. Colorimetric sensor for bad odor detection using automated color correction

    Science.gov (United States)

    Schmitt, K.; Tarantik, K.; Pannek, C.; Benito-Altamirano, I.; Casals, O.; Fàbrega, C.; Romano-Rodríguez, A.; Wöllenstein, J.; Prades, J. D.

    2017-06-01

    Colorimetric sensors based on color-changing dyes offer a convenient approach for the quantitative measurement of gases. An integrated, mobile colorimetric sensor can be particularly helpful for occasional gas measurements, such as informal air quality checks for bad odors. In these situations, the main requirement is high availability, easy usage, and high specificity towards one single chemical compound, combined with cost-efficient production. In this contribution, we show how a well stablished colorimetric method can be adapted for easy operation and readout, making it suitable for the untrained end user. As an example, we present the use of pH indicators for the selective and reversible detection of NH3 in air (one relevant gas contributing to bad odors) using gas-sensitive layers dip coated on glass substrates. Our results show that the method can be adapted to detect NH3 concentrations lower than 1 ppm, with measure-to-result times in the range of a few minutes. We demonstrate that the color measurements can be carried out with the optical signals of RGB sensors, without losing quantitative performance.

  8. Rapid and Reliable HPLC Method for the Determination of Vitamin ...

    African Journals Online (AJOL)

    Purpose: To develop and validate an accurate, sensitive and reproducible high performance liquid chromatographic (HPLC) method for the quantitation of vitamin C in pharmaceutical samples. Method: The drug and the standard were eluted from Superspher RP-18 (250 mm x 4.6 mm, 10ìm particle size) at 20 0C.

  9. Rapid, cost-effective liquid chromatograghic method for the ...

    African Journals Online (AJOL)

    The method is highly sensitive, with limit of detection of 1 ng/ml. The coefficient of variation for within-day run was less than 4% while that of day-to-day run was less than 6%. There were no interfering peaks from endogenous materials in the serum. The method was validated and used for pharmacokinetic studies ...

  10. A simple and rapid molecular method for Leptospira species identification

    NARCIS (Netherlands)

    Ahmed, Ahmed; Anthony, Richard M.; Hartskeerl, Rudy A.

    2010-01-01

    Serological and DNA-based classification systems only have little correlation. Currently serological and molecular methods for characterizing Leptospira are complex and costly restricting their world-wide distribution and use. Ligation mediated amplification combined with microarray analysis

  11. A method of rapid testing of radioactivity of different materials

    Directory of Open Access Journals (Sweden)

    Yu. Zabulonov

    2016-10-01

    Full Text Available A new method for the detection of low-level ionising radiation in solid, liquid or loose materials, which is based on the use of the Bayesian approach for the estimation of probabilistic parameters and a special statistical criterion, is offered in the present paper. We describe the algorithm and show the advantages of the method. The approach can be effective even in the case of extremely low signals whose intensity is much less than the background radiation.

  12. Colorimetric plasmon resonance microfluidics on nanohole array sensors

    Directory of Open Access Journals (Sweden)

    Austin Hsiao

    2015-09-01

    Full Text Available We present the label-free colorimetric visualization in microfluidics using plasmon resonance on a large-area and over a wide field-of-view (>100 mm2 nanohole array device called nanoLycurgus Cup Array (nanoLCA. We demonstrate the spectral detection and colorimetric sensing of static solutions of different concentrations of glycerol–water confined in parallel microfluidic channels integrated with nanoLCA. Taking advantage of the large sensor area and the colorimetric sensing capability of nanoLCA, we visualize in real-time the modulation of two immiscible solutions (water and oil, generated with integrated flow-focus microfluidics, in a label-free manner. Finite Element Method (FEM based simulation tool (COMSOL was used to verify the droplet formation in the microfluidics. Finite Difference Time Domain (FDTD electromagnetic simulation was used to identify the resonance modes of the plasmonic sensor. Finally, we demonstrate the real-time monitoring of streptavidin–biotin biomolecular interaction with the plasmonic biosensor.

  13. A rapid cloning method employing orthogonal end protection.

    Directory of Open Access Journals (Sweden)

    Arjen J Jakobi

    Full Text Available We describe a novel in vitro cloning strategy that combines standard tools in molecular biology with a basic protecting group concept to create a versatile framework for the rapid and seamless assembly of modular DNA building blocks into functional open reading frames. Analogous to chemical synthesis strategies, our assembly design yields idempotent composite synthons amenable to iterative and recursive split-and-pool reaction cycles. As an example, we illustrate the simplicity, versatility and efficiency of the approach by constructing an open reading frame composed of tandem arrays of a human fibronectin type III (FNIII domain and the von Willebrand Factor A2 domain (VWFA2, as well as chimeric (FNIII(n-VWFA2-(FNIII(n constructs. Although we primarily designed this strategy to accelerate assembly of repetitive constructs for single-molecule force spectroscopy, we anticipate that this approach is equally applicable to the reconstitution and modification of complex modular sequences including structural and functional analysis of multi-domain proteins, synthetic biology or the modular construction of episomal vectors.

  14. Rapid, specific and sensitive method for isoniazid determination in serum.

    Science.gov (United States)

    Sadeg, N; Pertat, N; Dutertre, H; Dumontet, M

    1996-01-12

    An original simple, specific and rapid high-performance liquid chromatographic assay for the determination of isoniazid (INH) in human serum is presented. The drug was extracted from the serum by protein precipitation with 30% (w/v) trichloroacetic acid, then the drug was reacted with the coupling reagent, trans-cinnamaldehyde, to form a derivative absorbing at 340 nm. A 20-microliters aliquot was injected into the chromatograph after neutralization with 1 M KOH solution. A liquid chromatograph equipped with a reversed-phase 30-microns C18 precolumn linked to a 4-microns C18 analytical column was used. The drug was eluted with a mixture of acetonitrile-water-triethylamine-acetic acid (400:600:2:1, v/v), pH value was 5 +/- 1. Flow-rate and wavelength were set at 1 ml/min and 340 nm, respectively. The extraction recoveries from human serum averaged 100% for INH at concentrations of 1, 2 and 4 mg/l. The coefficients of variation for three different concentrations for INH in serum in the within-day study varied between 1.2 and 3.5%, whereas those in the day-to-day study varied between 2.8 and 4.3%.

  15. Highly selective and sensitive colorimetric determination of Cr3 + ion by 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol functionalized Au nanoparticles

    Science.gov (United States)

    Shahrivari, Shima; Faridbod, Farnoush; Ganjali, Mohammad Reza

    2018-02-01

    In this work, a rapid, selective naked eyes colorimetric chemical probe for the detection of Cr3 + was developed based on functionalization of gold nanoparticles. For this purpose, surface of Au NPs was functionalized using 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol (AMTT). Through colorimetric studies, it was found that in the presence of Cr3 + ions, AMTT-Au NPs instantly aggregated and resulted in a color change of the solution from red to blue. The color change of AMTT-Au NPs due to the aggregation induced by Cr3 + can be seen with even naked eyes and also by UV-Vis spectroscopy with a detection limit of 1.8 μM and 0.1 μM, respectively. AMTT-Au NPs showed excellent selectivity toward Cr3 + compared to other cations tested, including K+, Na+, Cs+, Fe3 +, Ni2 +, Cu2 +, Co2 +, Zn2 +, Ba2 +, Ca2 +, Mg2 +, Cd2 +, Pb2 +, Hg2 + ions and especially all trivalent lanthanide ions. The absorbance ratio (A650/A525) was linear toward Cr3 + concentrations in the range of 0.6-6.1 μM (R2 = 0.996). The best response was achieved over a pH range of 3-5. Furthermore, the proposed colorimetric method based on AMTT-Au NPs was successfully used for Cr3 + ion detection in plasma sample and some water samples.

  16. Asymptotic and Numerical Methods for Rapidly Rotating Buoyant Flow

    Science.gov (United States)

    Grooms, Ian G.

    This thesis documents three investigations carried out in pursuance of a doctoral degree in applied mathematics at the University of Colorado (Boulder). The first investigation concerns the properties of rotating Rayleigh-Benard convection -- thermal convection in a rotating infinite plane layer between two constant-temperature boundaries. It is noted that in certain parameter regimes convective Taylor columns appear which dominate the dynamics, and a semi-analytical model of these is presented. Investigation of the columns and of various other properties of the flow is ongoing. The second investigation concerns the interactions between planetary-scale and mesoscale dynamics in the oceans. Using multiple-scale asymptotics the possible connections between planetary geostrophic and quasigeostrophic dynamics are investigated, and three different systems of coupled equations are derived. Possible use of these equations in conjunction with the method of superparameterization, and extension of the asymptotic methods to the interactions between mesoscale and submesoscale dynamics is ongoing. The third investigation concerns the linear stability properties of semi-implicit methods for the numerical integration of ordinary differential equations, focusing in particular on the linear stability of IMEX (Implicit-Explicit) methods and exponential integrators applied to systems of ordinary differential equations arising in the numerical solution of spatially discretized nonlinear partial differential equations containing both dispersive and dissipative linear terms. While these investigations may seem unrelated at first glance, some reflection shows that they are in fact closely linked. The investigation of rotating convection makes use of single-space, multiple-time-scale asymptotics to deal with dynamics strongly constrained by rotation. Although the context of thermal convection in an infinite layer seems somewhat removed from large-scale ocean dynamics, the asymptotic

  17. A colorimetric and smartphone readable method for uracil-DNA glycosylase detection based on the target-triggered formation of G-quadruplex.

    Science.gov (United States)

    Nie, Huaijun; Wang, Wei; Li, Wang; Nie, Zhou; Yao, Shouzhuo

    2015-04-21

    A simple, visible and smartphone readable strategy for the sensitive detection of uracil-DNA glycosylase (UDG) activity has been developed. This is based on the UDG-catalyzed removal of uracil bases, which induces the formation of a G-quadruplex-cofactor complex. The guanine-rich DNA probe can form a special G-quadruplex structure with hemin to display peroxidase activity and catalyze the H2O2-mediated oxidation of ABTS(2-) to the colored ABTS˙(-), providing a visible signal for UDG detection. The proposed sensing platform exhibits a good linear response to UDG concentrations ranging from 0.008 to 0.2 U mL(-1), with a low detection limit of 0.008 U mL(-1). Based on the theory of chromatics, we can directly read out the color value using a smartphone app to reflect the content of UDG with high resolution, providing a new vision for the portable assay strategy. Furthermore, the utility of this method for screening potential UDG inhibitors has also been demonstrated.

  18. Rapid, cost-effective liquid chromatograghic method for the ...

    African Journals Online (AJOL)

    GRACE

    2006-07-03

    Jul 3, 2006 ... Akay C, Ozkan SA, Senturk Z, Cevheroglu S (2002). Simultaneous determination of metronidazole and miconazole in pharmaceutical dosage form by HPLC. Farmaco. Nov.57(11): 953-7. Galmier MJ, Frasey AM, Bastide M, Beyssac E, Petit J, Aiache JM,. Lartigue-Mattei (1998). Simple and sensitive method ...

  19. RESEARCH NOTE A Universal, rapid, and inexpensive method for ...

    Indian Academy of Sciences (India)

    Navya

    very satisfactory for many researchers to prepare reagents for “all in one” ready to use method to extract gDNA from very wide range sources of blood samples. To meet these criteria, a universal and versatile DNA extraction procedure should be developedwith a minimal chemicals and equipment.On the other hand, the ...

  20. Rapid prototyping methods for the manufacture of fuel cells

    Directory of Open Access Journals (Sweden)

    Dudek Piotr

    2016-01-01

    The potential for the application of this method for the manufacture of metallic bipolar plates (BPP for use in proton exchange membrane fuel cells (PEMFCs is presented and discussed. Special attention is paid to the fabrication of light elements for the construction of PEMFC stacks designed for mobile applications such as aviation technology and unmanned aerial vehicles (UAVs.

  1. [Methods for the rapid preparation of paraffin blocks].

    Science.gov (United States)

    Shmurun, R I

    1992-01-01

    Two accelerated chloroform-paraffin processings of materials with the use of ultrasound (US) and microwave (MW) irradiation in the stove "Electronica" as well as a combined method with US- and MW-irradiation are proposed to shorten drastically the duration of the prehistologic processing.

  2. Rapid multi-residue method for the determination of pesticide ...

    African Journals Online (AJOL)

    Exposure to pesticides can represent a potential risk to humans. Agricultural workers are at risk of chronic toxicity. Hence, the evaluation of pesticide residues in their blood gives an indication about the extent of exposure and help in assessing adverse health effects. The aim of our study was to develop analytical method for ...

  3. Evaluation of the Randox colorimetric serum copper and zinc assays against atomic absorption spectroscopy.

    Science.gov (United States)

    Beckett, Jeffrey M; Hartley, Thomas F; Ball, Madeleine J

    2009-07-01

    Analysis of copper and zinc in serum is commonly performed using atomic absorption spectrometry (AAS); however, these methods are often not readily available in smaller laboratories. Randox colorimetric assays for copper and zinc in serum were evaluated on the Thermo Electron Data Pro analyser against flame AAS methods. Copper and zinc were measured in 48 serum samples using the Randox colorimetric copper (CU2340) and zinc (ZN2341) assays on the Data Pro analyser and the results compared with those from a Varian Spectra 880 atomic absorption spectrometer. A smaller set of samples (n = 15) were also analysed colorimetrically for zinc on the Roche Cobas Mira. Linear regression analyses of Bland and Altman plots from the Data Pro - AAS comparison gave the following results for copper: correlation r = 0.6669 (P < 0.01), slope = -0.2499 (P < 0.01), intercept = 3.219 (P < 0.01). For zinc, results were as follows: correlation r = 0.1976, slope = 0.1807, intercept = -1.922. For the smaller set of samples, the Cobas Mira - AAS comparison for zinc gave correlation r = 0.4379, slope = 0.5294, intercept = -4.074. The results indicated significant systematic and fixed bias between the colorimetric copper and the AAS method. Performances in comparison to AAS methods indicated the colorimetric methods, as used, are unsuitable for the accurate determination of copper and zinc in human serum.

  4. Time evolution of the wave equation using rapid expansion method

    KAUST Repository

    Pestana, Reynam C.

    2010-07-01

    Forward modeling of seismic data and reverse time migration are based on the time evolution of wavefields. For the case of spatially varying velocity, we have worked on two approaches to evaluate the time evolution of seismic wavefields. An exact solution for the constant-velocity acoustic wave equation can be used to simulate the pressure response at any time. For a spatially varying velocity, a one-step method can be developed where no intermediate time responses are required. Using this approach, we have solved for the pressure response at intermediate times and have developed a recursive solution. The solution has a very high degree of accuracy and can be reduced to various finite-difference time-derivative methods, depending on the approximations used. Although the two approaches are closely related, each has advantages, depending on the problem being solved. © 2010 Society of Exploration Geophysicists.

  5. A taxonomy of rapid reviews links report types and methods to specific decision-making contexts.

    Science.gov (United States)

    Hartling, Lisa; Guise, Jeanne-Marie; Kato, Elisabeth; Anderson, Johanna; Belinson, Suzanne; Berliner, Elise; Dryden, Donna M; Featherstone, Robin; Mitchell, Matthew D; Motu'apuaka, Makalapua; Noorani, Hussein; Paynter, Robin; Robinson, Karen A; Schoelles, Karen; Umscheid, Craig A; Whitlock, Evelyn

    2015-12-01

    Describe characteristics of rapid reviews and examine the impact of methodological variations on their reliability and validity. We conducted a literature review and interviews with organizations that produce rapid reviews or related products to identify methods, guidance, empiric evidence, and current practices. We identified 36 rapid products from 20 organizations (production time, 5 minutes to 8 months). Methods differed from systematic reviews at all stages. As time frames increased, methods became more rigorous; however, restrictions on database searching, inclusion criteria, data extracted, and independent dual review remained. We categorized rapid products based on extent of synthesis. "Inventories" list what evidence is available. "Rapid responses" present best available evidence with no formal synthesis. "Rapid reviews" synthesize the quality of and findings from the evidence. "Automated approaches" generate meta-analyses in response to user-defined queries. Rapid products rely on a close relationship with end users and support specific decisions in an identified time frame. Limited empiric evidence exists comparing rapid and systematic reviews. Rapid products have tremendous methodological variation; categorization based on time frame or type of synthesis reveals patterns. The similarity across rapid products lies in the close relationship with the end user to meet time-sensitive decision-making needs. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Multiplexed Colorimetric Solid-Phase Extraction

    Science.gov (United States)

    Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

    2009-01-01

    Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

  7. Systems and methods for rapid processing and storage of data

    Science.gov (United States)

    Stalzer, Mark A.

    2017-01-24

    Systems and methods of building massively parallel computing systems using low power computing complexes in accordance with embodiments of the invention are disclosed. A massively parallel computing system in accordance with one embodiment of the invention includes at least one Solid State Blade configured to communicate via a high performance network fabric. In addition, each Solid State Blade includes a processor configured to communicate with a plurality of low power computing complexes interconnected by a router, and each low power computing complex includes at least one general processing core, an accelerator, an I/O interface, and cache memory and is configured to communicate with non-volatile solid state memory.

  8. Development of a loop-mediated isothermal amplification method for rapid mass-screening of sand flies for Leishmania infection.

    Science.gov (United States)

    Nzelu, Chukwunonso O; Gomez, Eduardo A; Cáceres, Abraham G; Sakurai, Tatsuya; Martini-Robles, Luiggi; Uezato, Hiroshi; Mimori, Tatsuyuki; Katakura, Ken; Hashiguchi, Yoshihisa; Kato, Hirotomo

    2014-04-01

    Entomological monitoring of Leishmania infection in leishmaniasis endemic areas offers epidemiologic advantages for predicting the risk and expansion of the disease, as well as evaluation of the effectiveness of control programs. In this study, we developed a highly sensitive loop-mediated isothermal amplification (LAMP) method for the mass screening of sand flies for Leishmania infection based on the 18S rRNA gene. The LAMP technique could detect 0.01 parasites, which was more sensitive than classical PCR. The method was robust and could amplify the target DNA within 1h from a crude sand fly template without DNA purification. Amplicon detection could be accomplished by the newly developed colorimetric malachite green (MG)--mediated naked eye visualization. Pre-addition of MG to the LAMP reaction solution did not inhibit amplification efficiency. The field applicability of the colorimetric MG-based LAMP assay was demonstrated with 397 field-caught samples from the endemic areas of Ecuador and eight positive sand flies were detected. The robustness, superior sensitivity, and ability to produce better visual discriminatory reaction products than existing LAMP fluorescence and turbidity assays indicated the field potential usefulness of this new method for surveillance and epidemiological studies of leishmaniasis in developing countries. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Rapid new methods for paint collection and lead extraction.

    Science.gov (United States)

    Gutknecht, William F; Harper, Sharon L; Winstead, Wayne; Sorrell, Kristen; Binstock, David A; Salmons, Cynthia A; Haas, Curtis; McCombs, Michelle; Studabaker, William; Wall, Constance V; Moore, Curtis

    2009-01-01

    Chronic exposure of children to lead can result in permanent physiological impairment. In adults, it can cause irritability, poor muscle coordination, and nerve damage to the sense organs and nerves controlling the body. Surfaces coated with lead-containing paints are potential sources of exposure to lead. In April 2008, the U.S. Environmental Protection Agency (EPA) finalized new requirements that would reduce exposure to lead hazards created by renovation, repair, and painting activities, which disturb lead-based paint. On-site, inexpensive identification of lead-based paint is required. Two steps have been taken to meet this challenge. First, this paper presents a new, highly efficient method for paint collection that is based on the use of a modified wood drill bit. Second, this paper presents a novel, one-step approach for quantitatively grinding and extracting lead from paint samples for subsequent lead determination. This latter method is based on the use of a high-revolutions per minute rotor with stator to break up the paint into approximately 50 micron-size particles. Nitric acid (25%, v/v) is used to extract the lead in 95% for real-world paints, National Institute of Standards and Technology's standard reference materials, and audit samples from the American Industrial Hygiene Association's Environmental Lead Proficiency Analytical Testing Program. This quantitative extraction procedure, when paired with quantitative paint sample collection and lead determination, may enable the development of a lead paint test kit that will meet the specifications of the final EPA rule.

  10. Evaluation of colorimetric loop-mediated isothermal amplification assay for visual detection of Streptococcus agalactiae and Streptococcus iniae in tilapia.

    Science.gov (United States)

    Suebsing, R; Kampeera, J; Tookdee, B; Withyachumnarnkul, B; Turner, W; Kiatpathomchai, W

    2013-10-01

    Streptococcus agalactiae and Strep. iniae are bacterial pathogens that cause streptococcosis in many fish species. An accelerated colorimetric loop-mediated isothermal amplification (LAMP) assay with pre-addition of calcein was established, and the transmission and detection of Strep. agalactiae and Strep. iniae in tilapia under natural aquatic environment were investigated. A positive reaction was observed by a colour change from orange to green through the naked eyes after completion at 63°C for 30 min with 10 times higher sensitivity than that of nested PCR assays and without cross-amplification with other fish bacterial pathogens. All sample types of Nile and red tilapia (broodstock, fertilized egg, fry) were Strep. agalactiae- and Strep. iniae positive by this new method, implying that they could be vertically transmitted. With its application for screening broodstock and fry before stocking and for monitoring fish health in grow-out ponds, the method would become very useful in fish farming industry. The application of colorimetric LAMP with pre-addition of calcein offers simple, rapid and sensitive technique with applicability for small field laboratories. This technique explored the possible vertical transmission mode of Strep. agalactiae and Strep. iniae under natural aquatic environment. It could be such preliminary data provided for the screening broodstock before breeding and/or the specific-pathogen-free production. © 2013 The Society for Applied Microbiology.

  11. A colorimetric probe based on desensitized ionene-stabilized gold nanoparticles for single-step test for sulfate ions

    Science.gov (United States)

    Arkhipova, Viktoriya V.; Apyari, Vladimir V.; Dmitrienko, Stanislava G.

    2015-03-01

    Desensitized ionene-stabilized gold nanoparticles have been prepared and applied as a colorimetric probe for the single-step test for sulfate ions at the relatively high concentration level. The approach is based on aggregation of the nanoparticles leading to the change in absorption spectra and color of the solution. These nanoparticles are characterized by the decreased sensitivity due to both electrostatic and steric stabilization, which allows for simple, and rapid direct single-step determination of sulfate at the relatively high concentration level in real water samples without sample pretreatment or dilution. Influence of different factors (the time of interaction, pH, the concentrations of sulfate ions and the nanoparticles) on the aggregation and analytical performance of the procedure was investigated. The method allows for the determination of sulfate ions in the mass range of 0.2-0.4 mg with RSD of 5% from the sample volume of less than 2 mL. It has a sharp dependence of the colorimetric response on the concentration of sulfate, which makes it prospective for indicating deviations of the sulfate concentration regarding some declared value chosen within the above range. The time of the analysis is 2 min. The method was applied to the analysis of mineral water samples.

  12. Susceptibility testing of filamentous fungi to amphotericin B by a rapid radiometric method

    Energy Technology Data Exchange (ETDEWEB)

    Merz, W.G.; Fay, D.; Thumar, B.; Dixon, D.

    1984-01-01

    A rapid, radiometric method was developed to determine the susceptibility of filamentous fungi to amphotericin B. The rapid, radiometric method depended on measurement of the inhibition of /sup 24/CO/sub 2/ production in the presence of amphotericin B. Thirty isolates of filamentous fungi were tested by the rapid, radiometric method and a reference agar dilution method. There was 93% agreement between the two methods when an 80% or greater decrease in CO/sub 2/ production was used to calculate the minimal inhibitory concentration with the rapid, radiometric method. Minimal inhibitory concentrations, based on 80% decrease of CO/sub 2/ production, were achieved within 24 h of incubation with all of the fungi tested.

  13. Microwave as a rapid cooking method for beef tenderness evaluation.

    Science.gov (United States)

    Silva, Douglas R G; Fernandez, Ludimila C; Torres Filho, Robledo A; Fontes, Paulo R; Ramos, Alcinéia L S; Ramos, Eduardo M

    2017-11-20

    Semitendinosus (ST) muscle steaks were grouped according to three locations (proximal, middle, and distal end), grilled to endpoint temperature of 71C or cooked for 20, 30, 40, 50, or 60 s in a microwave oven (Mw). The location did not affect (p > .05) the cooking loss (CL) or shear force (SF) values. The CL increased (p  .05) from the grill samples. None of the microwaves' SF values were different (p > .05) from the grill values, with treatments Mw30 to Mw50 showing moderate repeatability (R = 0.51-0.60) and Mw30 and Mw60 showing higher correlations (r > .71) with grill values. Cooking beef strips with a microwave is a potential method for tenderness evaluation, but requires additional study to evaluate and optimize this application in different muscles and for comparison to sensorial data. The work was intended to evaluate the possibility of using a microwave oven for cooking meat to be used in objective measurement protocols for meat tenderness and to optimize the conditions for this purpose. The use of a standardized microwave procedure allows a dramatic reduction in analysis time and may reduce error variance due to nonuniform cooking procedures. © 2017 Wiley Periodicals, Inc.

  14. A method for rapid abundance estimation of semiplanktonic meiofauna

    Science.gov (United States)

    Armonies, Werner

    2000-12-01

    Many meiofaunal copepods and plathelminths enter the tidal waters at night thus exhibiting a life-style intermediate between benthic and planktonic. At the same time, ostracods may leave their interstitial dwelling and move across the sediment surface. In laboratory experiments, the percentage of plathelminth populations emerging from the sediment varied with the species, temperature, light conditions, and the dimensions of the sediment cores studied, but not with tidal level, season, ambient density of conspecifics, or the sediment composition. Therefore, the swimming activity may be utilised for extraction of semiplanktonic meiofauna provided that the extraction procedure is standardised with respect to temperature, light and core size. For free-living plathelminths from the Wadden Sea intertidal a robust standard procedure is as follows: sediment cores 1.6 cm in diameter (2 cm2 surface area) and 3 cm deep are fitted into cylindrical containers and submerged into aquaria containing filtered seawater (ambient salinity, room temperature, darkness) for 24 h. The sediment containers are then removed and the aquarian water filtered through appropriate meshes; the residue contains the emergent faunal component. For plathelminths, this procedure reduces sorting time by some 90% compared with the standard shaking-decantation method and thus makes it possible to process a high number of samples in a short time. Similar procedures may be developed for copepods and epibenthic ostracods.

  15. Rapid methods for the detection of foodborne bacterial pathogens: principles, applications, advantages and limitations

    Science.gov (United States)

    Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han

    2015-01-01

    The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases. PMID:25628612

  16. Rapid Methods for the Detection of Foodborne Bacterial Pathogens: Principles, Applications, Advantages and Limitations

    Directory of Open Access Journals (Sweden)

    Law eJodi Woan-Fei

    2015-01-01

    Full Text Available The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR, multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA, loop-mediated isothermal amplification (LAMP and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases.

  17. Methods and Magnitudes of Rapid Weight Loss in Judo Athletes Over Pre-Competition Periods

    Directory of Open Access Journals (Sweden)

    Kons Rafael Lima

    2017-06-01

    Full Text Available Purpose. The study aimed to analyse the methods and magnitudes of rapid weight loss (RWL in judo team members in distinct periods before the biggest state competition in Southern Brazil.

  18. Colorimetric values of esthetic stainless steel crowns.

    Science.gov (United States)

    Hosoya, Yumiko; Omachi, Koichi; Staninec, Michal

    2002-01-01

    The colorimetric values of two different kinds of esthetic stainless steel crowns were measured and compared with the colorimetric values of primary anterior teeth in Japanese children. The colorimetric values of resin composite-faced stainless steel crowns (Kinder Krown) and epoxy-coated stainless steel crowns (White Steel Crown) were measured with a color difference meter. The Commission Internationale de Eclairage L*, a*, b*, and delta E*ab values and Munsell value, chroma, and hue were calculated. The data were compared with previously reported colorimetric values of Japanese primary anterior teeth measured with the same color difference meter used in this study. Compared to Japanese primary anterior teeth, Kinder Krown Pedo I and Pedo II showed much higher L* values and lower hue; on the other hand, White Steel Crown showed much higher L*, a*, b* values, much higher value and chroma, and much lower hue. Color analysis revealed that the colors of the White Steel Crown and Kinder Krown Pedo I were substantially different from the color of Japanese primary anterior teeth. The color difference between Pedo II crowns and Japanese primary anterior teeth was relatively high, but the color of Pedo II might be acceptable for clinical use.

  19. Colorimetric Titration Experiment for the Undergraduate Laboratory.

    Science.gov (United States)

    Lopez, Edwin; Vassos, Basil H.

    1984-01-01

    Describes a colorimetric titration instrument usable in the undergraduate laboratory that fulfills the objectives of ruggedness, freedom from ambient light interference, and low cost. Although accessories can be added (raising the price), the basic instrument is low priced and can be used manually with a simple voltmeter. (JN)

  20. Quantification of 20-hydroxyeicosatetraenoic acid by colorimetric ...

    Indian Academy of Sciences (India)

    Quantification of 20-hydroxyeicosatetraenoic acid by colorimetric competitive enzyme linked immunosorbent assay. Harry E Grates Richard M Mc Gowen ... Assays were developed with and without a proprietary enhancer solution which allows for the extraction-free measurement of 20-HETE in urine samples. The bound ...

  1. Rapid identification of salmonella serotypes with stereo and hyperspectral microscope imaging Methods

    Science.gov (United States)

    The hyperspectral microscope imaging (HMI) method can reduce detection time within 8 hours including incubation process. The early and rapid detection with this method in conjunction with the high throughput capabilities makes HMI method a prime candidate for implementation for the food industry. Th...

  2. Colorimetric Determination of Cefadroxil and Ceftriazone in ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, rapid and selective method for the spectrophotometric determination of cefadroxil and ceftriaxone using 1, 2- napthaquinone-4- sulfonic acid sodium. Methods: The method was based on the derivatization of cefadroxil and ceftriaxone with 1, 2-naphthaquinone-4- sulfonic acid sodium in ...

  3. Assessment of three rapid methods for the detection of methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Soares, Maria João; Soares, Carlos; Mendes, Ana Constança; Guimarães, Maria Luís; Cabeda, José Manuel; Amorim, José Manuel

    2004-01-01

    We evaluated three rapid methods to detect methicillin-resistant Staphylococcus aureus (MRSA) and compared them with PCR amplification of mecA. A total of 103 S. aureus strains were studied by MRSA-Screen, BBL Crystal, Velogene Genomic and mecA PCR. All the methods detected the 61 MRSA strains having the mecA gene, showing 100% sensitivity and specificity. Despite the correlation between all the rapid methods and PCR, the ease of use and shorter turnaround time of MRSA-Screen were important factors leading to the selection of this method as the routine screening technique for MRSA.

  4. [Research on parameters of dynamic colorimetric temperature sensor and it's application to fuel air explosion temperature field detection].

    Science.gov (United States)

    Li, Lei; Liu, Qing-ming; Wang, Jian-ping

    2013-09-01

    According to the theory of colorimetric thermometry,the influences of center wavelength, wavelength bandwidth and solid angle on response speed and the precision of the sensor was analyzed systematically, and the operating parameters for transient high temperature measurement system were determined. A calculation method based on photoelectric conversion coefficient, and higher and lower operating wavelength of the colorimetric temperature sensor was given. At the optimal operating temperature, calibration experiment was conducted in a high temperature blackbody furnace. Based on the experimental results, the operating parameters of the sensor were determined and the colorimetric temperature response was calculated. The results show that the errors between the calculated response and the experiment one are less than 1%. By using the colorimetric temperature sensor, the temperature response of fuel air explosion field was detected and the variations of temperature with time and space in detonation field were obtained.

  5. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    Science.gov (United States)

    Tsai, Tsung-Ting; Shen, Shu-Wei; Cheng, Chao-Min; Chen, Chien-Fu

    2013-08-01

    A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h.

  6. Hybrid nanosensor for colorimetric and ultrasensitive detection of nuclease contaminations

    Science.gov (United States)

    Cecere, Paola; Valentini, Paola; Pompa, Pier Paolo

    2016-04-01

    Nucleases are ubiquitous enzymes that degrade DNA or RNA, thus they can prejudice the good outcome of molecular biology experiments involving nucleic acids. We propose a colorimetric test for the naked-eye detection of nuclease contaminations. The system uses an hybrid nanosensor, based on gold nanoparticles functionalized with DNA probes. Our assay is rapid, instrument-free, simple and low-cost. Moreover, it reaches sensitivity equal or better than those of commercial kits, and presents a lot of advantageous aspects. Therefore, it is very competitive, with a real market potential. This test will be relevant in routine process monitoring in scientific laboratories, and in quality control in clinical laboratories and industrial processes, allowing the simultaneous detection of nucleases with different substrate specificities and large-scale screening.

  7. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Tsung-Ting Tsai, Shu-Wei Shen, Chao-Min Cheng and Chien-Fu Chen

    2013-01-01

    Full Text Available A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h.

  8. The scope of application of incremental rapid prototyping methods in foundry engineering

    Directory of Open Access Journals (Sweden)

    M. Stankiewicz

    2010-01-01

    Full Text Available The article presents the scope of application of selected incremental Rapid Prototyping methods in the process of manufacturing casting models, casting moulds and casts. The Rapid Prototyping methods (SL, SLA, FDM, 3DP, JS are predominantly used for the production of models and model sets for casting moulds. The Rapid Tooling methods, such as: ZCast-3DP, ProMetalRCT and VoxelJet, enable the fabrication of casting moulds in the incremental process. The application of the RP methods in cast production makes it possible to speed up the prototype preparation process. This is particularly vital to elements of complex shapes. The time required for the manufacture of the model, the mould and the cast proper may vary from a few to several dozen hours.

  9. Evaluation of two methods of rapid blood-glucose monitoring by unskilled personnel during surgery

    DEFF Research Database (Denmark)

    Madsbad, S; Adelhøj, B; Bigler, Dennis Richard

    1984-01-01

    The accuracy of two rapid methods of blood-glucose monitoring without (Haemo-glucotest 1-44) and with a reflectance meter (Hypocount B) was compared using a laboratory method. The assessment was carried out by personnel with no previous experience in measuring blood glucose. Eighty-five percent o...

  10. A rapid and convenient method for preparing salt-free (. gamma. -/sup 32/P)ATP

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, J.L.; Avruch, J.

    1981-09-15

    (..gamma..-/sup 32/P)ATP is prepared by an existing enzymatic method that yields approximately 95% incorporation of /sup 32/P into ATP. A rapid and convenient method for purifying the (..gamma..-/sup 32/P)ATP which results in a product free of both salt and buffer is reported.

  11. High performance liquid chromatography method for rapid and accurate determination of homocysteine in plasma and serum

    DEFF Research Database (Denmark)

    Vester, Birte; Rasmussen, K

    1991-01-01

    Determination of homocysteine in plasma or serum for evaluation of cobalamin and folate deficiency is becoming an important diagnostic procedure. Accurate, rapid and low cost methods for measuring homocysteine are therefore required. We have improved an HPLC method and made it suitable for clinical...

  12. A rapid method to determine sterol, erythrodiol, and uvaol concentrations in olive oil.

    Science.gov (United States)

    Mathison, Brian; Holstege, Dirk

    2013-05-15

    A rapid, accurate, and efficient method for determining the sterol, uvaol, and erythrodiol concentrations was developed to meet International Olive Council (IOC) certification criteria for extra virgin olive oil (EVOO). The unsaponifiable fraction of the sample (0.2 g) was separated with a diatomaceous earth column, and the sterol and triterpenic dialcohols were isolated with a novel base-activated silica solid-phase extraction (SPE) cartridge cleanup protocol. The improved method and the IOC method provided identical pass/fail results (n = 34) for each of the six sterol and erythrodiol/uvaol IOC criteria used to assess olive oil. This method was validated, and recoveries of stigmasterol (88%) and β-sitosterol (84%) were greater than previously published values obtained using the IOC method. This method requires approximately one-third the time required to complete the IOC method and has great utility for the rapid screening of EVOO to detect adulteration, false labeling, and an inferior product.

  13. Colorimetric detection of endogenous hydrogen sulfide production in living cells

    Science.gov (United States)

    Ahn, Yong Jin; Lee, Young Ju; Lee, Jaemyeon; Lee, Doyeon; Park, Hun-Kuk; Lee, Gi-Ja

    2017-04-01

    Hydrogen sulfide (H2S) has received great attention as a third gaseous signal transmitter, following nitric oxide and carbon monoxide. In particular, H2S plays an important role in the regulation of cancer cell biology. Therefore, the detection of endogenous H2S concentrations within biological systems can be helpful to understand the role of gasotransmitters in pathophysiology. Although a simple and inexpensive method for the detection of H2S has been developed, its direct and precise measurement in living cells remains a challenge. In this study, we introduced a simple, facile, and inexpensive colorimetric system for selective H2S detection in living cells using a silver-embedded Nafion/polyvinylpyrrolidone (PVP) membrane. This membrane could be easily applied onto a polystyrene microplate cover. First, we optimized the composition of the coating membrane, such as the PVP/Nafion mixing ratio and AgNO3 concentration, as well as the pH of the Na2S (H2S donor) solution and the reaction time. Next, the in vitro performance of a colorimetric detection assay utilizing the silver/Nafion/PVP membrane was evaluated utilizing a known concentration of Na2S standard solution both at room temperature and at 37 °C in a 5% CO2 incubator. As a result, the sensitivity of the colorimetric assay for H2S at 37 °C in the incubator (0.0056 Abs./μM Na2S, R2 = 0.9948) was similar to that at room temperature (0.0055 Abs./μM Na2S, R2 = 0.9967). Moreover, these assays were less sensitive to interference from compounds such as glutathione, L-cysteine (Cys), and dithiothreitol than to the H2S from Na2S. This assay based on the silver/Nafion/PVP membrane also showed excellent reproducibility (2.8% RSD). Finally, we successfully measured the endogenous H2S concentrations in live C6 glioma cells by s-(5‧-adenosyl)-L-methionine stimulation with and without Cys and L-homocysteine, utilizing the silver/Nafion/PVP membrane. In summary, colorimetric assays using silver

  14. Smartphone-based colorimetric detection of glutathione.

    Science.gov (United States)

    Vobornikova, Irena; Pohanka, Miroslav

    2016-12-18

    /L. The smartphone-based assay seems to be promising because of simplicity, reliability, robustness and low cost. In spite of the fact that there is a large scale for approaches for the glutathione determination, the main advantage of our colorimetric method is portability and easibility to perform the assay in the field and publically availability of smartphones for home applications.

  15. Colorimetric estimation of total iridoid content of Picrorhiza kurrooa.

    Science.gov (United States)

    Narayanan, Pushpa; Akamanchi, K G

    2003-06-01

    A colorimetric method has been developed for the selective analysis of the total iridoid content of the rhizomes of Picrorhiza kurrooa in terms of catalpol. The method of analysis is based on the reaction between iridoid compounds and primary amine. The iridoid glycosides present in P. kurrooa are mainly the esters of catalpol, and can be easily converted into catalpol by saponification. Catalpol thus obtained by hydrolysis is treated with glycine in acidic medium to give a purple color with a maxmimum absorption of 542 nm. The method was validated as per the ICH guidelines for linearity, accuracy and precision. Several other rhizome samples of the plant were also assayed using this method. The method developed is precise, sensitive, reproducible and easy to perform and can be used for the standardization of crude drug.

  16. Commercially Available Rapid Methods for Detection of Selected Food-borne Pathogens.

    Science.gov (United States)

    Valderrama, Wladir B; Dudley, Edward G; Doores, Stephanie; Cutter, Catherine N

    2016-07-03

    Generally, the enumeration and isolation of food-borne pathogens is performed using culture-dependent methods. These methods are sensitive, inexpensive, and provide both qualitative and quantitative assessment of the microorganisms present in a sample, but these are time-consuming. For this reason, researchers are developing new techniques that allow detection of food pathogens in shorter period of time. This review identifies commercially available methods for rapid detection and quantification of Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Shiga toxin-producing Escherichia coli in food samples. Three categories are discussed: immunologically based methods, nucleic acid-based assays, and biosensors. This review describes the basic mechanism and capabilities of each method, discusses the difficulties of choosing the most convenient method, and provides an overview of the future challenges for the technology for rapid detection of microorganisms.

  17. A fast, sensitive and easy colorimetric assay for chitinase and cellulase activity detection.

    NARCIS (Netherlands)

    Ferrari, Alessandro; Gaber, Yasser; Fraaije, Marco

    2014-01-01

    BACKGROUND: Most of the current colorimetric methods for detection of chitinase or cellulase activities on the insoluble natural polymers chitin and cellulose depend on a chemical redox reaction. The reaction involves the reducing ends of the hydrolytic products. The Schales' procedure and the

  18. Rapid high temperature field test method for evaluation of geothermal calcite scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.

    1982-08-01

    A test method is described which allows the rapid field testing of calcite scale inhibitors in high- temperature geothermal brines. Five commercial formulations, chosen on the basis of laboratory screening tests, were tested in brines with low total dissolved solids at ca 500 F. Four were found to be effective; of these, 2 were found to be capable of removing recently deposited scale. One chemical was tested in the full-flow brine line for 6 wks. It was shown to stop a severe surface scaling problem at the well's control valve, thus proving the viability of the rapid test method. (12 refs.)

  19. Colorimetric evaluation of irradiated red beet roots

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Thaise C.F.; Rogovschi, Vladimir D.; Fabbri, Adriana D.T.; Sagretti, Juliana M.A.; Hirashima, Fabiana K.; Sabato, Susy F., E-mail: thaisecfnunes@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The red beetroot contain antioxidant and anticancer activity and have been consumed all over the world. In order to increase the consumption of beetroot the food industry has created a practical alternative, a beetroot shaped like a small ball, minimally processed with the convenience in meal preparation. Food irradiation is in consonance with the proposal to increase the consumption of beetroot whilst maintaining quality and product safety. The aim of this study was to analyze changes in colorimetric properties in beetroot after the irradiation process. Samples of minimally processed beetroot were purchased at a local supermarket. The samples were exposed to gamma rays with doses of 1.0kG{sub y}, 2.0kG{sub y}, 3.0kG{sub y} and 4.0 kG{sub y} and were stored at 5 deg C. Colorimetric characteristics were analyzed such as L{sup *}, a{sup *}, b{sup *}, C{sup *}, h{sup *}, δE and WI. The results of the colorimetric evaluation showed no significant difference among the samples. The authors concluded that the treatment with low doses of gamma radiation keeps the quality of beetroot. (author)

  20. Novel colorimetric sensor for oral malodour.

    Science.gov (United States)

    Alagirisamy, Nethaji; Hardas, Sarita S; Jayaraman, Sujatha

    2010-02-19

    Volatile sulphur compounds are the primary constituents of oral malodour. Quantitative tools for the detection of oral malodour are beneficial to evaluate the intensity of malodour, analyse its causes and monitor the effectiveness of customized treatments. We have developed an objective, cost effective, do-it-yourself colorimetric sensor for oral malodour quantification. The sensor consisted of a sensing solution, a gas sampling unit for collecting a known volume of mouth air and a photometric detector. The sensing solution was iodine and the depletion of iodine on reaction with hydrogen sulphide was detected colorimetrically using starch. The detection limit of the sensor is 0.05 microg L(-1) of hydrogen sulphide, which is fit-for-purpose for oral malodour detection in healthy subjects as well as halitosis patients. Volatile sulphur compounds in mouth air were quantified in healthy human volunteers using this portable sensor and the detected levels were in the range of 0.2-0.4 microg L(-1). There was a good correlation between the VSC levels detected by the colorimetric sensor and halimeter (R(2)=0.934). The developed sensor can be easily fabricated in the laboratory, and it shows high potential to be used as a clinical evaluation tool for oral malodour assessments. Copyright 2009 Elsevier B.V. All rights reserved.

  1. Novel colorimetric sensor for oral malodour

    Energy Technology Data Exchange (ETDEWEB)

    Alagirisamy, Nethaji; Hardas, Sarita S. [Hindustan Unilever Research Center, 64 Main Road, Whitefield, Bangalore 560066 (India); Jayaraman, Sujatha, E-mail: sujatha.jayaraman@unilever.com [Hindustan Unilever Research Center, 64 Main Road, Whitefield, Bangalore 560066 (India)

    2010-02-19

    Volatile sulphur compounds are the primary constituents of oral malodour. Quantitative tools for the detection of oral malodour are beneficial to evaluate the intensity of malodour, analyse its causes and monitor the effectiveness of customized treatments. We have developed an objective, cost effective, do-it-yourself colorimetric sensor for oral malodour quantification. The sensor consisted of a sensing solution, a gas sampling unit for collecting a known volume of mouth air and a photometric detector. The sensing solution was iodine and the depletion of iodine on reaction with hydrogen sulphide was detected colorimetrically using starch. The detection limit of the sensor is 0.05 {mu}g L{sup -1} of hydrogen sulphide, which is fit-for-purpose for oral malodour detection in healthy subjects as well as halitosis patients. Volatile sulphur compounds in mouth air were quantified in healthy human volunteers using this portable sensor and the detected levels were in the range of 0.2-0.4 {mu}g L{sup -1}. There was a good correlation between the VSC levels detected by the colorimetric sensor and halimeter (R{sup 2} = 0.934). The developed sensor can be easily fabricated in the laboratory, and it shows high potential to be used as a clinical evaluation tool for oral malodour assessments.

  2. Colorimetric sensing of malathion using palladium-gold bimetallic nanozyme.

    Science.gov (United States)

    Singh, Shefali; Tripathi, Pranav; Kumar, Nitin; Nara, Seema

    2017-06-15

    In this work, a simple, sensitive and selective label free colorimetric assay using palladium-gold nanorod as nanozyme is reported for malathion detection. Study investigates the peroxidase potential of the nanozyme on colorimetric substrates and explores the effect of selected organophosphates on their enzyme mimetic activity. Palladium-gold nanozyme shows excellent peroxidase mimetic activity with O-phenylenediamine in the presence of hydrogen peroxide. Its Kinetic parameters Km and kcat are better than horseradish peroxidase which makes it a superior enzyme. Nanozyme is stable over a broad temperature range (4-70°C) and shows high peroxidase activity from 2 to 6pH. The peroxidase activity of nanozyme is selectively quenched with increasing concentration of malathion and is the principle of developed assay. Assay has a lowest detection limit of 60ng/ml and shows no cross-reaction with other analogous organophosphates or metal salts. Validation on tap water samples spiked with different concentrations of malathion shows good recovery in the range of 80-106%. Assay also displays good intra and inter-assay precision which lie in the range of 2.7-6.1% and 3.2-5.9% respectively. This study demonstrated the catalytic potential of palladium-gold nanorods, which can be employed as nanozyme for developing highly sensitive detection methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. A Simple and Green Route for Room-Temperature Synthesis of Gold Nanoparticles and Selective Colorimetric Detection of Cysteine.

    Science.gov (United States)

    Bagci, Pelin Onsekizoglu; Wang, Yi-Cheng; Gunasekaran, Sundaram

    2015-09-01

    Gold nanoparticles (AuNPs) were synthesized at room temperature following a simple, rapid, and green route using fresh-squeezed apple juice as a reducing reagent. The optimal AuNPs, based on the particle color, stability, and color change suitable for colorimetric detection of cysteine (Cys), are synthesized using 5 mL of 10% apple juice, 1 mL of 10 mM gold precursor solution, and 1 mL of 0.1 M NaOH. Under this set of parameters, the AuNPs are synthesized within 30 min at room temperature. The average size (11.1 ± 3.2 nm) and ζ potential (-36.5 mV) of the AuNPs synthesized were similar to those of AuNPs prepared via the conventional citrate-reduction method. In the presence of Cys, unlike with any other amino acid, the AuNPs aggregated, possibly due to the gold-sulfur covalent interaction, yielding red-to-purple color change of the sample solution. The red-shift of the localized surface plasmon resonance peak of the AuNPs responsible for the color change was recorded by UV-vis spectrometer. The effect of other potential interferents such as glucose, ascorbic acid, K(+) , Na(+) , Ca(2+) , Zn(2+) , Ag(+) , Ni(2+) , Cu(2+) , Co(2+) , and Hg(2+) were also examined. The results show that AuNPs can be used to selectively detect and measure Cys with a linear dependency in the range of 2 to 100 μM and a limit of detection (signal-to-noise ratio > 3) of 50 nM. The results suggest that the green-synthesized AuNPs are useful for simple, rapid, and sensitive colorimetric detection of Cys, which is an essential amino acid in food and biological systems. © 2015 Institute of Food Technologists®

  4. [Rapid antibiotic susceptibility test in Clinical Microbiology].

    Science.gov (United States)

    March Rosselló, Gabriel Alberto; Bratos Pérez, Miguel Ángel

    2016-01-01

    The most widely used antibiotic susceptibility testing methods in Clinical Microbiology are based on the phenotypic detection of antibiotic resistance by measuring bacterial growth in the presence of the antibiotic being tested. These conventional methods take typically 24hours to obtain results. A review is presented here of recently developed techniques for the rapid determination of antibiotic susceptibility. Data obtained with different methods such as molecular techniques, flow cytometry, chemiluminescence, mass spectrometry, commercial methods used in routine work, colorimetric methods, nephelometry, microarrays, microfluids, and methods based on cell disruption and sequencing, are analyzed and discussed in detail. Copyright © 2014 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  5. Clinical chemistry measurements with commercially available test slides on a smartphone platform: Colorimetric determination of glucose and urea.

    Science.gov (United States)

    Wu, Yuanyuan; Boonloed, Anukul; Sleszynski, Neal; Koesdjojo, Myra; Armstrong, Chadd; Bracha, Shay; Remcho, Vincent T

    2015-08-25

    Rapidly increasing healthcare costs in economically advantaged countries are currently unsustainable, while in many developing nations, even 50-year-old technologies are too expensive to implement. New and unconventional technologies are being explored as solutions to this problem. In this study, we examined the use of a smartphone as the detection platform for 2 well-developed, relatively inexpensive, commercially available clinical chemistry assays as a model for rapid and inexpensive clinical diagnostic testing. An Apple iPhone 4 camera phone equipped with a color analysis application (ColorAssist) was combined with Vitros® glucose and urea colorimetric assays. Color images of assay slides at various concentrations of glucose or urea were collected with the iPhone 4 and quantitated in three different spectral ranges (red/green/blue or RGB) using the ColorAssist app. When the diffuse reflectance data was converted into absorbance, it was possible to quantitate glucose or blood urea nitrogen (BUN) over their clinically important concentration ranges (30-515mg/dl for glucose or 2-190mg/dl for BUN), with good linearity (R(2)=0.9994 or 0.9996, respectively [n=5]). Data collected using the iPhone 4 and canine serum samples were in agreement with results from the instrumental "gold standard" (Beckman Coulter AU480 Chemistry System) (R(2)=0.9966 and slope=1.0001 for glucose; R(2)=0.9958 and slope=0.9454 for BUN). Glucose determinations of serum samples made using this smartphone method were as accurate as or more accurate than a commercial colorimetric dry slide analyzer (Heska® Element DC Chemistry Analyzer, Loveland, CO) and 2 glucometers: ReliOn® Ultima (Abbott Diabetes Care Inc) and Presto® (AgaMatrix Inc.H). BUN determinations made using the smartphone approach were comparable in accuracy to the Heska instrument. This demonstration shows that smartphones have the potential to be used as simple, effective colorimetric detectors for quantitative diagnostic tests

  6. A rapid method for soil cement design : Louisiana slope value method.

    Science.gov (United States)

    1964-03-01

    The current procedure used by the Louisiana Department of Highways for laboratory design of cement stabilized soil base and subbase courses is taken from standard AASHO test methods, patterned after Portland Cement Association criteria. These methods...

  7. Non-crosslinking gold nanoprobe-LAMP for simple, colorimetric, and specific detection of Salmonella typhi

    Energy Technology Data Exchange (ETDEWEB)

    Bozorgmehr, Ali; Yazdanparast, Razieh, E-mail: ryazdan@ut.ac.ir [University of Tehran, Institute of Biochemistry and Biophysics (Iran, Islamic Republic of); Mollasalehi, Hamidreza [Shahid Beheshti University, Protein Research Center (Iran, Islamic Republic of)

    2016-12-15

    In this study, we developed a non-crosslinking gold nanoprobe loop-mediated isothermal amplification (LAMP) method for nanodiagnosis of bacterial typhoid fever source, Salmonella typhi. Therefore, a unique region in the S. typhi genomic DNA was targeted for LAMP amplification using a specific set of four precisely designed primers. Also, for specific colorimetric visualization of the amplicons, a thiolated oligonucleotide probe, complementary to the single-stranded loop region of the amplicons between F2 and F1C segments, was designed. The probe was bound to the surface of gold nanoparticles via covalent bonds. Increasing the salt concentration in the detection reaction medium led to aggregation of nanoprobes in the blank and the negative vessels in a time-dependent form. That was followed by a change in the surface plasmon resonance (SPR) leading to blue/black color that was observable by the naked eyes after about 5 min. Meanwhile, the original pink/red color was retained in the positive sample due to the large interparticle spaces and the stability against the ionic strength elevation which persisted for about 30 min. The whole process of DNA extraction, amplification, and detection took less than 2 h with a sensitivity of 20 CFU/ml. The developed gold nanoprobe-LAMP could serve as a simple, rapid, and cost-effective method for nanodiagnosis of S. typhi in point-of-need applications.

  8. Collaborative study of the colorimetric determination of zirconium in antiperspirant aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Beavin, P. Jr.

    1977-05-01

    A previously published method for determining zirconium in antiperspirant aerosols was collaboratively studied by 7 laboratories. The method consists of 2 procedures: a rapid dilution procedure for soluble zirconium compounds or a lengthier fusion procedure for total zirconium followed by colorimetric determination. The collaborators were asked to perform the following: Spiking materials representing 4 levels of soluble zirconium were added to weighed portions of a zirconium-free cream base concentrate and the portions were assayed by the dilution procedure. Spiking materials representing 4 levels of zirconium in either the soluble or the insoluble form (or as a mixture) were also added to portions of the same concentrate and these portions were assayed by the fusion procedure. They were also asked to concentrate and assay, by both procedures, 2 cans each of 2 commercial aerosol antiperspirants containing zirconyl hydroxychloride. The average percent recoveries and standard deviations for spiked samples were 99.8-100.2 and 1.69-2.71, respectively, for soluble compounds determined by the dilution procedure, and 93.8-97.4 and 3.09-4.78, respectively, for soluble and/or insoluble compounds determined by the fusion procedure. The average perent zirconium found by the dilution procedure in the 2 commercial aerosol products was 0.751 and 0.792. Insufficient collaborative results were received for the fusion procedure for statistical evaluation. The dilution procedure has been adopted as official first action.

  9. Non-crosslinking gold nanoprobe-LAMP for simple, colorimetric, and specific detection of Salmonella typhi

    Science.gov (United States)

    Bozorgmehr, Ali; Yazdanparast, Razieh; Mollasalehi, Hamidreza

    2016-12-01

    In this study, we developed a non-crosslinking gold nanoprobe loop-mediated isothermal amplification (LAMP) method for nanodiagnosis of bacterial typhoid fever source, Salmonella typhi. Therefore, a unique region in the S. typhi genomic DNA was targeted for LAMP amplification using a specific set of four precisely designed primers. Also, for specific colorimetric visualization of the amplicons, a thiolated oligonucleotide probe, complementary to the single-stranded loop region of the amplicons between F2 and F1C segments, was designed. The probe was bound to the surface of gold nanoparticles via covalent bonds. Increasing the salt concentration in the detection reaction medium led to aggregation of nanoprobes in the blank and the negative vessels in a time-dependent form. That was followed by a change in the surface plasmon resonance (SPR) leading to blue/black color that was observable by the naked eyes after about 5 min. Meanwhile, the original pink/red color was retained in the positive sample due to the large interparticle spaces and the stability against the ionic strength elevation which persisted for about 30 min. The whole process of DNA extraction, amplification, and detection took less than 2 h with a sensitivity of 20 CFU/ml. The developed gold nanoprobe-LAMP could serve as a simple, rapid, and cost-effective method for nanodiagnosis of S. typhi in point-of-need applications.

  10. Gold nanoparticles mediated colorimetric assay for HIV-Tat protein detection

    Science.gov (United States)

    Hashwan, Saeed S. Ba; Ruslinda, A. Rahim; Fatin, M. F.; Gopinath, Subash C. B.; Thivina, V.; Tony, V. C. S.; Arshad, M. K. Md.; Hashim, U.

    2016-07-01

    Gold-nanoparticle (AuNP) based colorimetric assays have been formulated for different biomolecular interactions. With this assay the probe such as antibody immobilized on the Au surface and in the presence of appropriate binding partner (antigen), will interact with each other on the Au surface. By following this strategy, herein we formulated a detection system with two anti-HIV-Tat antibodies, Mono (McAb) - and polyclonal (PcAb) by immobilizing them independently with different AuNPs. Under this condition, these two antibodies are under dispersed condition, and in the presence of HIV-Tat antigen, these molecules will be connected and forms the aggregation of AuNPs. This strategy yield rapid results, can be monitored by the spectral changes in UV-Vis spectrophotometry. Experiments were performed with two different methods using two anti-HIV-Tats monoclonal and one Polyclonal antibody against the antigen HIV-Tat. Between these methods conjugation of HIV-Tat and McAb on the AuNP followed by addition of PcAb yielded better results.

  11. Furuncular myiasis: a simple and rapid method for extraction of intact Dermatobia hominis larvae.

    Science.gov (United States)

    Boggild, Andrea K; Keystone, Jay S; Kain, Kevin C

    2002-08-01

    We report a case of furuncular myiasis complicated by Staphylococcus aureus infection and beta-hemolytic streptococcal cellulitis. The Dermatobia hominis larva that caused this lesion could not be extracted using standard methods, including suffocation and application of lateral pressure, and surgery was contraindicated because of cellulitis. The botfly maggot was completely and rapidly extracted with an inexpensive, disposable, commercial venom extractor.

  12. Collision-induced fragmentation accurate mass spectrometric analysis methods to rapidly characterize phytochemicals in plant extracts

    Science.gov (United States)

    The rapid advances in analytical chromatography equipment have made the reliable and reproducible measurement of a wide range of plant chemical components possible. Full chemical characterization of a given plant material is possible with the new mass spectrometers currently available. New methods a...

  13. Collaborative validation of a rapid method for efficient virus concentration in bottled water

    DEFF Research Database (Denmark)

    Schultz, Anna Charlotte; Perelle, Sylvie; Di Pasquale, Simona

    2011-01-01

    Enteric viruses, including norovirus (NoV) and hepatitis A virus (HAV), have emerged as a major cause of waterborne outbreaks worldwide. Due to their low infectious doses and low concentrations in water samples, an efficient and rapid virus concentration method is required for routine control. Th...

  14. A Rapid Method for Measuring Strontium-90 Activity in Crops in China

    Directory of Open Access Journals (Sweden)

    Pan Lingjing Pan

    2017-01-01

    Full Text Available A rapid method for measuring Sr-90 activity in crop ashes is presented. Liquid scintillation counting, combined with ion exchange columns 4‘, 4“(5“-di-t-butylcyclohexane-18-crown-6, is used to determine the activity of Sr-90 in crops. The yields of chemical procedure are quantified using gravimetric analysis. The conventional method that uses ion-exchange resin with HDEHP could not completely remove all the bismuth when comparatively large lead and bismuth exist in the samples. This is overcome by the rapid method. The chemical yield of this method is about 60% and the MDA for Sr-90 is found to be 2:32 Bq/kg. The whole procedure together with using spectrum analysis to determine the activity only takes about one day, which is really a large improvement compared with the conventional method. A modified conventional method is also described here to verify the value of the rapid one. These two methods can meet di_erent needs of daily monitoring and emergency situation.

  15. A Rapid Method for Measuring Strontium-90 Activity in Crops in China

    Science.gov (United States)

    Pan, Lingjing Pan; Yu, Guobing; Wen, Deyun; Chen, Zhi; Sheng, Liusi; Liu, Chung-King; Xu, X. George

    2017-09-01

    A rapid method for measuring Sr-90 activity in crop ashes is presented. Liquid scintillation counting, combined with ion exchange columns 4`, 4"(5")-di-t-butylcyclohexane-18-crown-6, is used to determine the activity of Sr-90 in crops. The yields of chemical procedure are quantified using gravimetric analysis. The conventional method that uses ion-exchange resin with HDEHP could not completely remove all the bismuth when comparatively large lead and bismuth exist in the samples. This is overcome by the rapid method. The chemical yield of this method is about 60% and the MDA for Sr-90 is found to be 2:32 Bq/kg. The whole procedure together with using spectrum analysis to determine the activity only takes about one day, which is really a large improvement compared with the conventional method. A modified conventional method is also described here to verify the value of the rapid one. These two methods can meet di_erent needs of daily monitoring and emergency situation.

  16. Considerations for Task Analysis Methods and Rapid E-Learning Development Techniques

    Directory of Open Access Journals (Sweden)

    Dr. Ismail Ipek

    2014-02-01

    Full Text Available The purpose of this paper is to provide basic dimensions for rapid training development in e-learning courses in education and business. Principally, it starts with defining task analysis and how to select tasks for analysis and task analysis methods for instructional design. To do this, first, learning and instructional technologies as visions of the future were discussed. Second, the importance of task analysis methods in rapid e-learning was considered, with learning technologies as asynchronous and synchronous e-learning development. Finally, rapid instructional design concepts and e-learning design strategies were defined and clarified with examples, that is, all steps for effective task analysis and rapid training development techniques based on learning and instructional design approaches were discussed, such as m-learning and other delivery systems. As a result, the concept of task analysis, rapid e-learning development strategies and the essentials of online course design were discussed, alongside learner interface design features for learners and designers.

  17. An economical and combined method for rapid and efficient isolation of fungal DNA.

    Science.gov (United States)

    Lech, T; Syguła-Cholewinska, J; Szostak-Kot, J

    2014-12-18

    DNA isolation is a crucial step of conducting genetic studies in any organism. However, this process is quite difficult when studying fungi because of the need to damage the fungal cell walls of specific structures. In this study, we developed a method for the rapid and efficient isolation of fungal DNA based on simultaneous mechanical and enzymatic cell wall degradation. There are several typical modifications of the standard phenol-chloroform DNA extraction method. This method can be modified to degrade the fungal cell wall. The first step of the presented DNA extraction included manual homogenization in modified lysis buffer. Next, enzymatic digestion using 2 enzymes was conducted, including lyticase and proteinase K. To carefully select the most favorable conditions, we developed an economical, rapid, and reliable method for fungal DNA extraction that ensures both high efficiency and proper purity, which are essential for further analyses.

  18. Rapid method for determination of carbonyl groups in lignin compounds by headspace gas chromatography.

    Science.gov (United States)

    Li, Jing; Hu, Hui-Chao; Chai, Xin-Sheng

    2015-07-24

    The paper reports on a novel method for rapid determination of carbonyl in lignins by headspace gas chromatography (HS-GC). The method involves the quantitative carbonyl reduction for aldehydes in 2min at room temperature or for acetones in 30min at 80°C by sodium borohydride solution in a closed headspace sample vial. After the reaction, the solution was acidified by injecting sulfuric acid solution and the hydrogen released to the headspace was determined by GC using thermal-conductivity detector. The results showed that with the addition of SiO2 powder, the reduction reaction of carbonyl groups can be greatly facilitated. The method has a good measurement precision (RSD<7.74%) and accuracy (relative error <10% compared with a reference method) in the carbonyl quantification. It is suitable to be used for rapid determination of carbonyl content in lignin and related materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Multidimensional colorimetric sensor array for discrimination of proteins.

    Science.gov (United States)

    Mao, Jinpeng; Lu, Yuexiang; Chang, Ning; Yang, Jiaoe; Zhang, Sichun; Liu, Yueying

    2016-12-15

    An extensible multidimensional colorimetric sensor array for the detection of protein is developed based on DNA functionalized gold nanoparticles (DNA-AuNPs) as receptors. In the presence of different proteins, the aggregation behavior of DNA-AuNPs was regulated by the high concentrations of salt and caused different color change; while DNA-AuNPs grew induced by the reduction of HAuCl4 and NH2OH as a reductant on the surface of nanoparticles exhibited different morphologies and color appearance for different proteins. The transducers based on AuNPs modified by specific and nonspecific DNA enables naked-eye discrimination of the target analytes. This extensible sensing platform with only two receptors could simultaneously discriminate ten native proteins and their thermally denatured conformations using hierarchical cluster analysis (HCA) at the concentration of 50nM with 100% accuracy. This opens up the possibility of the sensor array to investigate the different conformational changes of biomacromolecules, and it gives a new direction of developing multidimensional transduction principles based on plasmonic nanoparticle conjugates. Furthermore, the sensing system could discriminate proteins at the concentration of 500nM in the presence of 50% human urine, which indicated this sensor array has great potential ability in analyzing real biological fluids. In addition, the multidimensional colorimetric sensor array is suitable for analysis of target analytes in the resource-restricted regions because of rapid, simple, low cost, and in-field detection with the naked eye. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Apparatus and method for rapid separation and detection of hydrocarbon fractions in a fluid stream

    Science.gov (United States)

    Sluder, Charles S.; Storey, John M.; Lewis, Sr., Samuel A.

    2013-01-22

    An apparatus and method for rapid fractionation of hydrocarbon phases in a sample fluid stream are disclosed. Examples of the disclosed apparatus and method include an assembly of elements in fluid communication with one another including one or more valves and at least one sorbent chamber for removing certain classifications of hydrocarbons and detecting the remaining fractions using a detector. The respective ratios of hydrocarbons are determined by comparison with a non separated fluid stream.

  1. A convenient and rapid method for genetic transformation of E. coli with plasmids.

    Science.gov (United States)

    Chen, X; Guo, P; Xie, Z; Shen, P

    2001-12-01

    A convenient and rapid method for the genetic transformation of Escherichia coli with plasmids is proposed. By mixing the recipient cells and plasmid DNA and spreading them directly on selective medium plates containing Ca2+, the so-called 'plate transformation' could achieve almost the same transformation efficiency as the classical transformation method with calcium. The whole protocol takes only about 2 min, its simplicity compared favorably, not only to the usual protocol, but also to all other documented modifications.

  2. A comparison of two colorimetric assays, based upon Lowry and Bradford techniques, to estimate total protein in soil extracts.

    Science.gov (United States)

    Redmile-Gordon, M A; Armenise, E; White, R P; Hirsch, P R; Goulding, K W T

    2013-12-01

    Soil extracts usually contain large quantities of dissolved humified organic material, typically reflected by high polyphenolic content. Since polyphenols seriously confound quantification of extracted protein, minimising this interference is important to ensure measurements are representative. Although the Bradford colorimetric assay is used routinely in soil science for rapid quantification protein in soil-extracts, it has several limitations. We therefore investigated an alternative colorimetric technique based on the Lowry assay (frequently used to measure protein and humic substances as distinct pools in microbial biofilms). The accuracies of both the Bradford assay and a modified Lowry microplate method were compared in factorial combination. Protein was quantified in soil-extracts (extracted with citrate), including standard additions of model protein (BSA) and polyphenol (Sigma H1675-2). Using the Lowry microplate assay described, no interfering effects of citrate were detected even with concentrations up to 5 times greater than are typically used to extract soil protein. Moreover, the Bradford assay was found to be highly susceptible to two simultaneous and confounding artefacts: 1) the colour development due to added protein was greatly inhibited by polyphenol concentration, and 2) substantial colour development was caused directly by the polyphenol addition. In contrast, the Lowry method enabled distinction between colour development from protein and non-protein origin, providing a more accurate quantitative analysis. These results suggest that the modified-Lowry method is a more suitable measure of extract protein (defined by standard equivalents) because it is less confounded by the high polyphenolic content which is so typical of soil extracts.

  3. Rapid qualitative research methods during complex health emergencies: A systematic review of the literature.

    Science.gov (United States)

    Johnson, Ginger A; Vindrola-Padros, Cecilia

    2017-09-01

    The 2013-2016 Ebola outbreak in West Africa highlighted both the successes and limitations of social science contributions to emergency response operations. An important limitation was the rapid and effective communication of study findings. A systematic review was carried out to explore how rapid qualitative methods have been used during global heath emergencies to understand which methods are commonly used, how they are applied, and the difficulties faced by social science researchers in the field. We also asses their value and benefit for health emergencies. The review findings are used to propose recommendations for qualitative research in this context. Peer-reviewed articles and grey literature were identified through six online databases. An initial search was carried out in July 2016 and updated in February 2017. The PRISMA checklist was used to guide the reporting of methods and findings. The articles were assessed for quality using the MMAT and AACODS checklist. From an initial search yielding 1444 articles, 22 articles met the criteria for inclusion. Thirteen of the articles were qualitative studies and nine used a mixed-methods design. The purpose of the rapid studies included: the identification of causes of the outbreak, and assessment of infrastructure, control strategies, health needs and health facility use. The studies varied in duration (from 4 days to 1 month). The main limitations identified by the authors were: the low quality of the collected data, small sample sizes, and little time for cross-checking facts with other data sources to reduce bias. Rapid qualitative methods were seen as beneficial in highlighting context-specific issues that need to be addressed locally, population-level behaviors influencing health service use, and organizational challenges in response planning and implementation. Recommendations for carrying out rapid qualitative research in this context included the early designation of community leaders as a point of

  4. Seed oil polyphenols: rapid and sensitive extraction method and high resolution-mass spectrometry identification.

    Science.gov (United States)

    Koubaa, Mohamed; Mhemdi, Houcine; Vorobiev, Eugène

    2015-05-01

    Phenolic content is a primary parameter for vegetables oil quality evaluation, and directly involved in the prevention of oxidation and oil preservation. Several methods have been reported in the literature for polyphenols extraction from seed oil but the approaches commonly used remain manually handled. In this work, we propose a rapid and sensitive method for seed oil polyphenols extraction and identification. For this purpose, polyphenols were extracted from Opuntia stricta Haw seed oil, using high frequency agitation, separated, and then identified using a liquid chromatography-high resolution mass spectrometry method. Our results showed good sensitivity and reproducibility of the developed methods. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. RAPID AND EFFICIENT METHOD FOR ENVIRONMENTAL DNA EXTRACTION AND PURIFICATION FROM SOIL

    Directory of Open Access Journals (Sweden)

    J. Hamedi

    2016-06-01

    Full Text Available Large proportion of microbial population in the world is unculturable. Extraction of total DNA from soil is usually a crucial step considering to the difficulties of study the uncultivable microorganisms. Humic acid is considered as the main inhibitory agent in the environmental DNA studies. Here, we introduced a rapid and efficient method for DNA extraction and purification from soil. Yield of DNA extraction by the presented method was 130 ng/µl. Three conventional methods of DNA extraction including liquid nitrogen incursion, bead beating and sonication were performed as control methods. Yield of DNA extraction by these methods were 110, 90 and 50 ng/µl, respectively. A rapid and efficient one step DNA purification method was introduced instead of hazardous conventional phenol-chloroform methods. Humic acid removal percentage by the introduced method was 95.8 % that is comparable with 97 % gained by the conventional gel extraction method and yield of DNA after purification was 84 % and 73 %, respectively. This study could be useful in molecular ecology and metagenomics study as a fast and reliable method.

  6. The use of rapid review methods in health technology assessments: 3 case studies.

    Science.gov (United States)

    Kaltenthaler, Eva; Cooper, Katy; Pandor, Abdullah; Martyn-St James, Marrissa; Chatters, Robin; Wong, Ruth

    2016-08-26

    Rapid reviews are of increasing importance within health technology assessment due to time and resource constraints. There are many rapid review methods available although there is little guidance as to the most suitable methods. We present three case studies employing differing methods to suit the evidence base for each review and outline some issues to consider when selecting an appropriate method. Three recently completed systematic review short reports produced for the UK National Institute for Health Research were examined. Different approaches to rapid review methods were used in the three reports which were undertaken to inform the commissioning of services within the NHS and to inform future trial design. We describe the methods used, the reasoning behind the choice of methods and explore the strengths and weaknesses of each method. Rapid review methods were chosen to meet the needs of the review and each review had distinctly different challenges such as heterogeneity in terms of populations, interventions, comparators and outcome measures (PICO) and/or large numbers of relevant trials. All reviews included at least 10 randomised controlled trials (RCTs), each with numerous included outcomes. For the first case study (sexual health interventions), very diverse studies in terms of PICO were included. P-values and summary information only were presented due to substantial heterogeneity between studies and outcomes measured. For the second case study (premature ejaculation treatments), there were over 100 RCTs but also several existing systematic reviews. Data for meta-analyses were extracted directly from existing systematic reviews with new RCT data added where available. For the final case study (cannabis cessation therapies), studies included a wide range of interventions and considerable variation in study populations and outcomes. A brief summary of the key findings for each study was presented and narrative synthesis used to summarise results for each

  7. Colorimetric determination of ambient ozone using indigo blue droplet

    Directory of Open Access Journals (Sweden)

    Felix Erika P.

    2006-01-01

    Full Text Available A simple and sensitive method based on a liquid droplet is described for the measurement of atmospheric ozone. A 30 µL drop of indigo blue solution is suspended in a flowing-air sampling stream. The ozone collected reacts with the indigo solution resulting in its decolorization. The colorimetric sensor is composed of two optical fibers and the source of monochromatic light was a red LED (625 nm. The calibration curve was constructed with ozone standard concentrations ranging from 37 - 123 ppbv. The detection limit achieved was 7.3 ppbv. The method considered here showed itself to be easy to apply with a fast response and a total analysis time of only 5 minutes.

  8. Fluorescent and Colorimetric Electrospun Nanofibers for Heavy-Metal Sensing

    Directory of Open Access Journals (Sweden)

    Idelma A. A. Terra

    2017-12-01

    Full Text Available The accumulation of heavy metals in the human body and/or in the environment can be highly deleterious for mankind, and currently, considerable efforts have been made to develop reliable and sensitive techniques for their detection. Among the detection methods, chemical sensors appear as a promising technology, with emphasis on systems employing optically active nanofibers. Such nanofibers can be obtained by the electrospinning technique, and further functionalized with optically active chromophores such as dyes, conjugated polymers, carbon-based nanomaterials and nanoparticles, in order to produce fluorescent and colorimetric nanofibers. In this review we survey recent investigations reporting the use of optically active electrospun nanofibers in sensors aiming at the specific detection of heavy metals using colorimetry and fluorescence methods. The examples given in this review article provide sufficient evidence of the potential of optically electrospun nanofibers as a valid approach to fabricate highly selective and sensitive optical sensors for fast and low-cost detection of heavy metals.

  9. [Development of a rapid test kit for antibody to HIV by nano immunomagnetic lateral flow method].

    Science.gov (United States)

    Yang, Fa-qing; Lee, Tony; Wang, Chao-nan; Sun, Shu-ye; Li, Shan-shan; Tian, Hui

    2010-06-01

    To develop a rapid test kit for antibody to HIV by nano immunomagnetic lateral flow method. A rapid test kit was developed by conjugation of the HIV antigen gp41 and gp36 to 200nm super paramagnetic particles by carbodiimide (EDC) and coating of the HIV antigen gp41 and gp36 to nitrocellulose membrane. Then the kit was evaluated with serials of experiments. The kit was qualified with examination of national reference panel of anti-HIV antibody for colloidal gold diagnostic kit. The sensitivity was 100% by tested with 20 HIV antibody positive sera, the specificity was 98.5% by tested with 600 HIV antibody negative sera, respectively. The stability of the kit was over 12 month by storage at room temperature. A diagnostic kit for antibody to HIV was developed with the advantages of convenience, rapid test, good stability and point of care.

  10. Fósforo extraído pela solução de Mehlich-1 determinado por colorimetria e ICP em solos do Sul do Brasil Phosphorus extracted with Mehlich-1 determined by colorimetric and ICP methods in South Brazilian soils

    Directory of Open Access Journals (Sweden)

    Leandro Bortolon

    2010-02-01

    Full Text Available A adoção do ICP para análise de fósforo tem apresentado controvérsias, pois o valor determinado por essa técnica, muitas vezes, não é comparável com o obtido por colorimetria. Nos EUA, alguns laboratórios apresentam restrições à adoção dessa técnica, pelas seguintes razões: as recomendações de adubação em uso foram desenvolvidas empregando-se o método colorimétrico para a determinação do P; e as diferenças significativas têm sido obtidas entre os teores determinados por colorimetria e por ICP, pois, devido à alta temperatura do plasma, o ICP mede outras formas de P além do ortofosfato, atribuída ao P orgânico na solução. Este estudo teve por objetivo comparar os teores de P extraído do solo pela solução de Mehlich-1, determinado por colorimetria (COL e por ICP, em 595 amostras de solos do Estado do Rio Grande do Sul, com amplas variações nas características físicas, químicas e mineralógicas. Os teores de P extraído, determinado por ICP e por COL, não diferiram estatisticamente (r = 0,94; p The adoption of ICP technique to determine P in soil testing has been questioned, due the values determined with this technique is not comparable that those determined with colorimetric method. In the USA, some laboratories are restricted to adopt the ICP technique due the follow reasons: the nutrient recommendations to plants were developed for colorimetric method for P determination; significantly differences have been obtained between P determined with colorimetric and ICP techniques, because the high plasma temperature can measure other P forms besides orthophosphate, attributed to organic P in solution. This study compared the P amounts extracted by Mehlich-1 solution and determined by COL and ICP techniques, in 595 soil samples from the state of Rio Grande do Sul (Brazil with s wide range of soil physic, chemistry and mineralogic properties. The P amounts determined by ICP and COL did not differ statistically

  11. Rapid culture-based methods for drug-resistance detection in Mycobacterium tuberculosis.

    Science.gov (United States)

    Palomino, Juan Carlos; Martin, Anandi; Von Groll, Andrea; Portaels, Francoise

    2008-10-01

    Tuberculosis still represents a major public health problem, especially in low-resource countries where the burden of the disease is more important. Multidrug-resistant and extensively drug drug-resistant tuberculosis constitute serious problems for the efficient control of the disease stressing the need to investigate resistance to first- and second-line drugs. Conventional methods for detecting drug-resistance in Mycobacterium tuberculosis are slow and cumbersome. The most commonly used proportion method on Löwenstein-Jensen medium or Middlebrook agar requires a minimum of 3-4 weeks to produce results. Several new approaches have been proposed in the last years for the rapid and timely detection of drug-resistance in tuberculosis. This review will address phenotypic culture-based methods for rapid drug susceptibility testing in M. tuberculosis.

  12. Rapid Column Extraction Method for Actinides and Sr-89/90 in Water Samples

    Energy Technology Data Exchange (ETDEWEB)

    MAXWELL III, SHERROD L.

    2005-06-15

    The SRS Environmental Laboratory analyzes water samples for environmental monitoring, including river water and ground water samples. A new, faster actinide and strontium 89/90 separation method has been developed and implemented to improve productivity, reduce labor costs and add capacity to this laboratory. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and Sr-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu), neptunium (Np), uranium (U), americium (Am), curium (Cm) and thorium (Th) using a single multi-stage column combined with alpha spectrometry. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized. The method can be used for routine analysis or as a rapid method for emergency preparedness. Thorium and curium are often analyzed separately due to the interference of the daughter of Th-229 tracer, actinium (Ac)-225, on curium isotopes when measured by alpha spectrometry. This new method also adds a separation step using DGA Resin{reg_sign}, (Diglycolamide Resin, Eichrom Technologies) to remove Ac-225 and allow the separation and analysis of thorium isotopes and curium isotopes at the same time.

  13. Mycobacteria mobility shift assay: a method for the rapid identification of Mycobacterium tuberculosis and nontuberculous mycobacteria

    Directory of Open Access Journals (Sweden)

    Letícia Muraro Wildner

    2014-06-01

    Full Text Available The identification of mycobacteria is essential because tuberculosis (TB and mycobacteriosis are clinically indistinguishable and require different therapeutic regimens. The traditional phenotypic method is time consuming and may last up to 60 days. Indeed, rapid, affordable, specific and easy-to-perform identification methods are needed. We have previously described a polymerase chain reaction-based method called a mycobacteria mobility shift assay (MMSA that was designed for Mycobacterium tuberculosis complex (MTC and nontuberculous mycobacteria (NTM species identification. The aim of this study was to assess the MMSA for the identification of MTC and NTM clinical isolates and to compare its performance with that of the PRA-hsp65 method. A total of 204 clinical isolates (102 NTM and 102 MTC were identified by the MMSA and PRA-hsp65. For isolates for which these methods gave discordant results, definitive species identification was obtained by sequencing fragments of the 16S rRNA and hsp65 genes. Both methods correctly identified all MTC isolates. Among the NTM isolates, the MMSA alone assigned 94 (92.2% to a complex or species, whereas the PRA-hsp65 method assigned 100% to a species. A 91.5% agreement was observed for the 94 NTM isolates identified by both methods. The MMSA provided correct identification for 96.8% of the NTM isolates compared with 94.7% for PRA-hsp65. The MMSA is a suitable auxiliary method for routine use for the rapid identification of mycobacteria.

  14. Adapting and Evaluating a Rapid, Low-Cost Method to Enumerate Flies in the Household Setting.

    Science.gov (United States)

    Wolfe, Marlene K; Dentz, Holly N; Achando, Beryl; Mureithi, MaryAnne; Wolfe, Tim; Null, Clair; Pickering, Amy J

    2017-02-08

    Diarrhea is a leading cause of death among children under 5 years of age worldwide. Flies are important vectors of diarrheal pathogens in settings lacking networked sanitation services. There is no standardized method for measuring fly density in households; many methods are cumbersome and unvalidated. We adapted a rapid, low-cost fly enumeration technique previously developed for industrial settings, the Scudder fly grill, for field use in household settings. We evaluated its performance in comparison to a sticky tape fly trapping method at latrine and food preparation areas among households in rural Kenya. The grill method was more sensitive; it detected the presence of any flies at 80% (433/543) of sampling locations versus 64% (348/543) of locations by the sticky tape. We found poor concordance between the two methods, suggesting that standardizing protocols is important for comparison of fly densities between studies. Fly species identification was feasible with both methods; however, the sticky tape trap allowed for more nuanced identification. Both methods detected a greater presence of bottle flies near latrines compared with food preparation areas (P < 0.01). The grill method detected more flies at the food preparation area compared with near the latrine (P = 0.014) while the sticky tape method detected no difference. We recommend the Scudder grill as a sensitive fly enumeration tool that is rapid and low cost to implement. © The American Society of Tropical Medicine and Hygiene.

  15. Rapid and effective DNA extraction method with bead grinding for a large amount of fungal DNA.

    Science.gov (United States)

    Watanabe, M; Lee, K; Goto, K; Kumagai, S; Sugita-Konishi, Y; Hara-Kudo, Y

    2010-06-01

    To identify a rapid method for extracting a large amount of DNA from fungi associated with food hygiene, extraction methods were compared using fungal pellets formed rapidly in liquid media. Combinations of physical and chemical methods or commercial kits were evaluated with 3 species of yeast, 10 species of ascomycetous molds, and 4 species of zygomycetous molds. Bead grinding was the physical method, followed by chemical methods involving sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), and benzyl chloride and two commercial kits. Quantity was calculated by UV absorbance at 260 nm, quality was determined by the ratio of UV absorbance at 260 and 280 nm, and gene amplifications and electrophoresis profiles of whole genomes were analyzed. Bead grinding with the SDS method was the most effective for DNA extraction for yeasts and ascomycetous molds, and bead grinding with the CTAB method was most effective with zygomycetous molds. For both groups of molds, bead grinding with the CTAB method was the best approach for DNA extraction. Because this combination also is relatively effective for yeasts, it can be used to extract a large amount of DNA from a wide range of fungi. The DNA extraction methods are useful for developing gene indexes to identify fungi with molecular techniques, such as DNA fingerprinting.

  16. Mycobacteria mobility shift assay: a method for the rapid identification of Mycobacterium tuberculosis and nontuberculous mycobacteria.

    Science.gov (United States)

    Wildner, Letícia Muraro; Bazzo, Maria Luiza; Liedke, Susie Coutinho; Nogueira, Christiane Lourenço; Segat, Gabriela; Senna, Simone Gonçalves; Schlindwein, Aline Daiane; Oliveira, Jaquelline Germano de; Rovaris, Darcita B; Bonjardim, Claudio A; Kroon, Erna G; Ferreira, Paulo C P

    2014-06-01

    The identification of mycobacteria is essential because tuberculosis (TB) and mycobacteriosis are clinically indistinguishable and require different therapeutic regimens. The traditional phenotypic method is time consuming and may last up to 60 days. Indeed, rapid, affordable, specific and easy-to-perform identification methods are needed. We have previously described a polymerase chain reaction-based method called a mycobacteria mobility shift assay (MMSA) that was designed for Mycobacterium tuberculosis complex (MTC) and nontuberculous mycobacteria (NTM) species identification. The aim of this study was to assess the MMSA for the identification of MTC and NTM clinical isolates and to compare its performance with that of the PRA-hsp65 method. A total of 204 clinical isolates (102 NTM and 102 MTC) were identified by the MMSA and PRA-hsp65. For isolates for which these methods gave discordant results, definitive species identification was obtained by sequencing fragments of the 16S rRNA and hsp65 genes. Both methods correctly identified all MTC isolates. Among the NTM isolates, the MMSA alone assigned 94 (92.2%) to a complex or species, whereas the PRA-hsp65 method assigned 100% to a species. A 91.5% agreement was observed for the 94 NTM isolates identified by both methods. The MMSA provided correct identification for 96.8% of the NTM isolates compared with 94.7% for PRA-hsp65. The MMSA is a suitable auxiliary method for routine use for the rapid identification of mycobacteria.

  17. A rapid chromatographic method for quality control of technetium-99m-bicisate.

    Science.gov (United States)

    Amin, K C; Saha, G B; Go, R T

    1997-03-01

    The purpose of this work was to develop a simple and rapid method to determine the radiochemical purity of 99mTc-bicisate. A rapid paper chromatographic (PC) method was developed to determine the radiochemical purity of 99mTc-bicisate and compare the results with those of the manufacturer's recommended method. The present PC method included Whatman 3MM paper as the solid phase and ethyl acetate as the solvent. The time for chromatography by this technique was 4-5 min compared to about 23 min by the manufacturer's method. The Rf value of 99mTc-bicisate (Rf = 0.9-1.0) was widely different from those of 99mTcO4- and reduced 99mTc (Rf = 0.0 for both) so the chromatographic strip after development could be readily cut into two segments, in order to determine the labeling yield. No significant difference in labeling yields was found between the present method and the manufacturer's method. The PC method using Whatman 3MM paper and ethyl acetate is a simple and fast technique to determine the radiochemical purity of 99mTc-bicisate and may be substituted for the manufacturer's recommended method to save time.

  18. A rapid method for soil cement design : Louisiana slope value method : part II : evaluation.

    Science.gov (United States)

    1966-05-01

    This report is an evaluation of the recently developed "Louisiana Slope Value Method". : The conclusion drawn are based on data from 637 separate samples representing nearly all major soil groups in Louisiana that are suitable for cement stabilizatio...

  19. Melting Temperature Mapping Method: A Novel Method for Rapid Identification of Unknown Pathogenic Microorganisms within Three Hours of Sample Collection.

    Science.gov (United States)

    Niimi, Hideki; Ueno, Tomohiro; Hayashi, Shirou; Abe, Akihito; Tsurue, Takahiro; Mori, Masashi; Tabata, Homare; Minami, Hiroshi; Goto, Michihiko; Akiyama, Makoto; Yamamoto, Yoshihiro; Saito, Shigeru; Kitajima, Isao

    2015-07-28

    Acquiring the earliest possible identification of pathogenic microorganisms is critical for selecting the appropriate antimicrobial therapy in infected patients. We herein report the novel "melting temperature (Tm) mapping method" for rapidly identifying the dominant bacteria in a clinical sample from sterile sites. Employing only seven primer sets, more than 100 bacterial species can be identified. In particular, using the Difference Value, it is possible to identify samples suitable for Tm mapping identification. Moreover, this method can be used to rapidly diagnose the absence of bacteria in clinical samples. We tested the Tm mapping method using 200 whole blood samples obtained from patients with suspected sepsis, 85% (171/200) of which matched the culture results based on the detection level. A total of 130 samples were negative according to the Tm mapping method, 98% (128/130) of which were also negative based on the culture method. Meanwhile, 70 samples were positive according to the Tm mapping method, and of the 59 suitable for identification, 100% (59/59) exhibited a "match" or "broad match" with the culture or sequencing results. These findings were obtained within three hours of whole blood collection. The Tm mapping method is therefore useful for identifying infectious diseases requiring prompt treatment.

  20. 3D virtual human rapid modeling method based on top-down modeling mechanism

    Directory of Open Access Journals (Sweden)

    LI Taotao

    2017-01-01

    Full Text Available Aiming to satisfy the vast custom-made character demand of 3D virtual human and the rapid modeling in the field of 3D virtual reality, a new virtual human top-down rapid modeling method is put for-ward in this paper based on the systematic analysis of the current situation and shortage of the virtual hu-man modeling technology. After the top-level realization of virtual human hierarchical structure frame de-sign, modular expression of the virtual human and parameter design for each module is achieved gradu-al-level downwards. While the relationship of connectors and mapping restraints among different modules is established, the definition of the size and texture parameter is also completed. Standardized process is meanwhile produced to support and adapt the virtual human top-down rapid modeling practice operation. Finally, the modeling application, which takes a Chinese captain character as an example, is carried out to validate the virtual human rapid modeling method based on top-down modeling mechanism. The result demonstrates high modelling efficiency and provides one new concept for 3D virtual human geometric mod-eling and texture modeling.

  1. Development of a loop-mediated isothermal amplification method for rapid detection of pigeon circovirus.

    Science.gov (United States)

    Tsai, Shinn Shyong; Chang, Yeng Ling; Huang, Yen Li; Liu, Hung Jen; Ke, Guan Ming; Chiou, Chwei Jang; Hsieh, Yao Ching; Chang, Tsung Chou; Cheng, Li Ting; Chuang, Kuo Pin

    2014-05-01

    There are no effective antiviral treatments for pigeon circovirus (PiCV); thus, rapid diagnosis is critical for effective control of the disease caused by this virus. The recent development of a novel LAMP technique that amplifies nucleic acids rapidly with high specificity and sensitivity under isothermal conditions has overcome some of the deficiencies of nucleic-acid-based diagnostic tests. We established a LAMP method for rapid detection of PiCV using two pairs of primers that were designed from PiCV and compared its sensitivity and specificity with that of PCR. Amplification by LAMP was optimal at 63 °C for 60 min. The detection limit was nearly 0.5 pg of PiCV DNA, making it ten times more sensitive than PCR. There was no cross-reaction with porcine circovirus type 2 (PCV2), pigeon Trichomonas gallinae, or pigeon herpesvirus (PHV) under the same conditions. The assay also successfully detected the pathogen DNA in the tissues of infected pigeons. This is the first report indicating that LAMP is a valuable, rapid method of detecting PiCV with high sensitivity and specificity.

  2. Prediction of warmed-over flavour development in cooked chicken by colorimetric sensor array.

    Science.gov (United States)

    Kim, Su-Yeon; Li, Jinglei; Lim, Na-Ri; Kang, Bo-Sik; Park, Hyun-Jin

    2016-11-15

    The aim of this study was to develop a simple and rapid method based on colorimetric sensor array (CSA) for evaluation of warmed-over flavour (WOF) in cooked chicken. All samples were classified according to storage time by CSA coupled with principle component analysis (PCA) or hierarchical cluster analysis (HCA). The CSA data were used to establish prediction models with thiobarbituric acid reactive substances (TBARS), pentanal, hexanal, or heptanal associated with WOF by partial least square regression (PLSR). For the TBARS model, the coefficient of determination (rp(2)) was 0.9997 in the prediction range of 0.28-0.69mg/kg. In each of the models for pentanal, hexanal, and heptanal, all rp(2) were higher than 0.960 in the range of 0.58-2.10mg/kg, 5.50-11.69mg/kg, and 0.09-0.16mg/kg, respectively. These results demonstrate that the CSA was able to predict WOF development and to distinguish between each storage time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. A new alginate-based rapid method for determining coliforms in milk.

    Science.gov (United States)

    Chang, Su-sen; Gray, Peter M; Woo, Gun-Jo; Kang, Dong-Hyun

    2003-11-01

    A new rapid method for monitoring coliforms was developed on the basis of the instant gelling effects of alginate and calcium. The effectiveness of this new method in the detection of coliforms was evaluated. Tests involving Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, total coliforms in milk, cold-injured coliforms, and total coliforms in raw milk were carried out. The bacterial samples were diluted in 0.2% peptone water containing 90 mM CaCl2 and added into test tubes containing modified purple broth base medium. Coliform concentrations were determined on the basis of the time of color change and gas production in the alginate tubes. All results obtained by the alginate method correlated strongly with those obtained by the conventional violet red bile agar (VRBA) plating method. The alginate method reduced detection time by 12 to 14 h compared with the conventional VRBA plating method. The alginate method can be applied in field studies more easily than melted-agar systems can. The results of this study indicate that the alginate method is an accurate, rapid, simple, and economical way to monitor and estimate concentrations of total coliforms in food.

  4. New method for vitrifying water and other liquids by rapid cooling of their aerosols

    Science.gov (United States)

    Mayer, Erwin

    1985-07-01

    A method for the vitrification of pure liquid water and dilute aqueous solutions is described which is the only one without a liquid cryomedium for heat transfer: rapid cooling of aqueous aerosol droplets on a solid cryoplate. This method is not limited to water and aqueous solutions, but can be used for the vitrification of any liquid aerosol, the only impurity being some codeposited vapor. The method can be applied in diverse fields such as cryobiology, cryomicroscopy, and low-temperature spectroscopy of water and dilute aqueous solutions to avoid the formation of crystalline ice.

  5. Rapid simulation of electromagnetic telemetry using an axisymmetric semianalytical finite element method

    Science.gov (United States)

    Chen, Jiefu; Zeng, Shubin; Dong, Qiuzhao; Huang, Yueqin

    2017-02-01

    An axisymmetric semianalytical finite element method is proposed and employed for rapid simulations of electromagnetic telemetry in layered underground formation. In this method, the layered media is decomposed into several subdomains and the interfaces between subdomains are discretized by conventional finite elements. Then a Riccati equation based high precision integration scheme is applied to exploit the homogeneity along the vertical direction in each layer. This semianalytical finite element scheme is very efficient in modeling electromagnetic telemetry in layered formation. Numerical examples as well as a field case with water based mud as drilling fluid are given to demonstrate the validity and effectiveness of this method.

  6. RAPID METHOD FOR PLUTONIUM, AMERICIUM AND CURIUM IN VERY LARGE SOIL SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S

    2007-01-08

    The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring. There is a need to measure actinide isotopes with very low detection limits. A new, rapid actinide separation method has been developed and implemented that allows the measurement of plutonium, americium and curium isotopes in very large soil samples (100-200 g) with high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu), americium (Am), and curium (Cm) using a single multistage column combined with alpha spectrometry. The method combines an acid leach step and innovative matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. This method is unique in that it provides high tracer recoveries and effective removal of interferences with small extraction chromatography columns instead of large ion exchange resin columns that generate large amounts of acid waste. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

  7. A novel sample preparation method using rapid nonheated saponification method for the determination of cholesterol in emulsified foods.

    Science.gov (United States)

    Jeong, In-Seek; Kwak, Byung-Man; Ahn, Jang-Hyuk; Leem, Donggil; Yoon, Taehyung; Yoon, Changyong; Jeong, Jayoung; Park, Jung-Min; Kim, Jin-Man

    2012-10-01

    In this study, nonheated saponification was employed as a novel, rapid, and easy sample preparation method for the determination of cholesterol in emulsified foods. Cholesterol content was analyzed using gas chromatography with a flame ionization detector (GC-FID). The cholesterol extraction method was optimized for maximum recovery from baby food and infant formula. Under these conditions, the optimum extraction solvent was 10 mL ethyl ether per 1 to 2 g sample, and the saponification solution was 0.2 mL KOH in methanol. The cholesterol content in the products was determined to be within the certified range of certified reference materials (CRMs), NIST SRM 1544 and SRM 1849. The results of the recovery test performed using spiked materials were in the range of 98.24% to 99.45% with an relative standard devitation (RSD) between 0.83% and 1.61%. This method could be used to reduce sample pretreatment time and is expected to provide an accurate determination of cholesterol in emulsified food matrices such as infant formula and baby food. A novel, rapid, and easy sample preparation method using nonheated saponification was developed for cholesterol detection in emulsified foods. Recovery tests of CRMs were satisfactory, and the recoveries of spiked materials were accurate and precise. This method was effective and decreased the time required for analysis by 5-fold compared to the official method. © 2012 Institute of Food Technologists®

  8. A Rapid and Economical Method for Efficient DNA Extraction from Diverse Soils Suitable for Metagenomic Applications.

    Directory of Open Access Journals (Sweden)

    Selvaraju Gayathri Devi

    Full Text Available A rapid, cost effective method of metagenomic DNA extraction from soil is a useful tool for environmental microbiology. The present work describes an improved method of DNA extraction namely "powdered glass method" from diverse soils. The method involves the use of sterile glass powder for cell lysis followed by addition of 1% powdered activated charcoal (PAC as purifying agent to remove humic substances. The method yielded substantial DNA (5.87 ± 0.04 μg/g of soil with high purity (A260/280: 1.76 ± 0.05 and reduced humic substances (A340: 0.047 ± 0.03. The quality of the extracted DNA was compared against five different methods based on 16S rDNA PCR amplification, BamHI digestion and validated using quantitative PCR. The digested DNA was used for a metagenomic library construction with the transformation efficiency of 4 X 106 CFU mL-1. Besides providing rapid, efficient and economical extraction of metgenomic DNA from diverse soils, this method's applicability is also demonstrated for cultivated organisms (Gram positive B. subtilis NRRL-B-201, Gram negative E. coli MTCC40, and a microalgae C. sorokiniana UTEX#1666.

  9. A Rapid and Economical Method for Efficient DNA Extraction from Diverse Soils Suitable for Metagenomic Applications.

    Science.gov (United States)

    Devi, Selvaraju Gayathri; Fathima, Anwar Aliya; Radha, Sudhakar; Arunraj, Rex; Curtis, Wayne R; Ramya, Mohandass

    2015-01-01

    A rapid, cost effective method of metagenomic DNA extraction from soil is a useful tool for environmental microbiology. The present work describes an improved method of DNA extraction namely "powdered glass method" from diverse soils. The method involves the use of sterile glass powder for cell lysis followed by addition of 1% powdered activated charcoal (PAC) as purifying agent to remove humic substances. The method yielded substantial DNA (5.87 ± 0.04 μg/g of soil) with high purity (A260/280: 1.76 ± 0.05) and reduced humic substances (A340: 0.047 ± 0.03). The quality of the extracted DNA was compared against five different methods based on 16S rDNA PCR amplification, BamHI digestion and validated using quantitative PCR. The digested DNA was used for a metagenomic library construction with the transformation efficiency of 4 X 106 CFU mL-1. Besides providing rapid, efficient and economical extraction of metgenomic DNA from diverse soils, this method's applicability is also demonstrated for cultivated organisms (Gram positive B. subtilis NRRL-B-201, Gram negative E. coli MTCC40, and a microalgae C. sorokiniana UTEX#1666).

  10. Simple and rapid method for the isolation of forskolin from Coleus forskohlii by charcoal column chromatography.

    Science.gov (United States)

    Saleem, A M; Dhasan, P B; Rafiullah, M R M

    2006-01-06

    A simple, safe, rapid and economical method was developed for the isolation of high-purity forskolin from Coleus forskohlii roots using activated charcoal as an adsorbent in a column. The elution was carried out under reduced pressure to make the process rapid. Activated charcoal acted as a reversed phase adsorbent and allowed elution of forskolin without much impurities. The residue, obtained from the eluate was purified and crystallized using different solvent mixtures to obtain pure forskolin. The forskolin isolated was analyzed and characterized by UV, IR, RP-HPLC, electrospray ionization MS, 1H NMR and 13C NMR. The yield was 0.097% w/w (RSD 5.6%). The purity was 96.9% w/w (RSD 0.3%) as determined by RP-HPLC. The present method enables researchers to produce high-purity forskolin in their labs by using common chemicals.

  11. Evaluation of methods for rapid determination of freezing point of aviation fuels

    Science.gov (United States)

    Mathiprakasam, B.

    1982-01-01

    Methods for identification of the more promising concepts for the development of a portable instrument to rapidly determine the freezing point of aviation fuels are described. The evaluation process consisted of: (1) collection of information on techniques previously used for the determination of the freezing point, (2) screening and selection of these techniques for further evaluation of their suitability in a portable unit for rapid measurement, and (3) an extensive experimental evaluation of the selected techniques and a final selection of the most promising technique. Test apparatuses employing differential thermal analysis and the change in optical transparency during phase change were evaluated and tested. A technique similar to differential thermal analysis using no reference fuel was investigated. In this method, the freezing point was obtained by digitizing the data and locating the point of inflection. Results obtained using this technique compare well with those obtained elsewhere using different techniques. A conceptual design of a portable instrument incorporating this technique is presented.

  12. Rapid direct methods for enumeration of specific, active bacteria in water and biofilms

    Science.gov (United States)

    McFeters, G. A.; Pyle, B. H.; Lisle, J. T.; Broadaway, S. C.

    1999-01-01

    Conventional methods for detecting indicator and pathogenic bacteria in water may underestimate the actual population due to sublethal environmental injury, inability of the target bacteria to take up nutrients and other physiological factors which reduce bacterial culturability. Rapid and direct methods are needed to more accurately detect and enumerate active bacteria. Such a methodological advance would provide greater sensitivity in assessing the microbiological safety of water and food. The principle goal of this presentation is to describe novel approaches we have formulated for the rapid and simultaneous detection of bacteria plus the determination of their physiological activity in water and other environmental samples. The present version of our method involves the concentration of organisms by membrane filtration or immunomagnetic separation and combines an intracellular fluorochrome (CTC) for assessment of respiratory activity plus fluorescent-labelled antibody detection of specific bacteria. This approach has also been successfully used to demonstrate spatial and temporal heterogeneities of physiological activities in biofilms when coupled with cryosectioning. Candidate physiological stains include those capable of determining respiratory activity, membrane potential, membrane integrity, growth rate and cellular enzymatic activities. Results obtained thus far indicate that immunomagnetic separation can provide a high degree of sensitivity in the recovery of seeded target bacteria (Escherichia coli O157:H7) in water and hamburger. The captured and stained target bacteria are then enumerated by either conventional fluorescence microscopy or ChemScan(R), a new instrument that is very sensitive and rapid. The ChemScan(R) laser scanning instrument (Chemunex, Paris, France) provides the detection of individual fluorescently labelled bacterial cells using three emission channels in less than 5 min. A high degree of correlation has been demonstrated between

  13. New multiplex PCR methods for rapid screening of genetically modified organisms in foods

    OpenAIRE

    Nelly eDatukishvili; Tamara eKutateladze; Inga eGabriadze; Kakha eBitskinashvili; Boris eVishnepolsky

    2015-01-01

    We present novel multiplex PCR methods for rapid and reliable screening of genetically modified organisms (GMOs). New designed PCR primers targeting four frequently used GMO specific sequences permitted identification of new DNA markers, in particular 141 bp fragment of cauliflower mosaic virus (CaMV) 35S promoter, 224 bp fragment of Agrobacterium tumefaciens nopaline synthase (NOS) terminator, 256 bp fragment of 5-enolppyruvylshikimate-phosphate synthase (epsps) gene and 258 bp fragment of C...

  14. A low complexity rapid molecular method for detection of Clostridium difficile in stool.

    Directory of Open Access Journals (Sweden)

    Cathal J McElgunn

    Full Text Available Here we describe a method for the detection of Clostridium difficile from stool using a novel low-complexity and rapid extraction process called Heat Elution (HE. The HE method is two-step and takes just 10 minutes, no specialist instruments are required and there is minimal hands-on time. A test method using HE was developed in conjunction with Loop-mediated Isothermal Amplification (LAMP combined with the real-time bioluminescent reporter system known as BART targeting the toxin B gene (tcdB. The HE-LAMP-BART method was evaluated in a pilot study on clinical fecal samples (tcdB(+, n = 111; tcdB(-, n= 107. The HE-LAMP-BART method showed 95.5% sensitivity and 100% specificity against a gold standard reference method using cytotoxigenic culture and also a silica-based robotic extraction followed by tcdB PCR to control for storage. From sample to result, the HE-LAMP-BART method typically took 50 minutes, whereas the PCR method took >2.5 hours. In a further study (tcdB(+, n = 47; tcdB(-, n= 28 HE-LAMP-BART was compared to an alternative commercially available LAMP-based method, Illumigene (Meridian Bioscience, OH, and yielded 87.2% sensitivity and 100% specificity for the HE-LAMP-BART method compared to 76.6% and 100%, respectively, for Illumigene against the reference method. A subset of 27 samples (tcdB(+, n = 25; tcdB(-, n= 2 were further compared between HE-LAMP-BART, Illumigene, GeneXpert (Cepheid, Sunnyvale, CA and RIDA®QUICK C. difficile Toxin A/B lateral flow rapid test (R-Biopharm, Darmstadt, Germany resulting in sensitivities of HE-LAMP-BART 92%, Illumigene 72% GeneXpert 96% and RIDAQuick 76% against the reference method. The HE-LAMP-BART method offers the advantages of molecular based approaches without the cost and complexity usually associated with molecular tests. Further, the rapid time-to-result and simple protocol means the method can be applied away from the centralized laboratory settings.

  15. Conventional rapid latex agglutination in estimation of von Willebrand factor: method revisited and potential clinical applications.

    Science.gov (United States)

    Mahat, Marianor; Abdullah, Wan Zaidah; Hussin, Che Maraina Che

    2014-01-01

    Measurement of von Willebrand factor antigen (VWF : Ag) levels is usually performed in a specialised laboratory which limits its application in routine clinical practice. So far, no commercial rapid test kit is available for VWF : Ag estimation. This paper discusses the technical aspect of latex agglutination method which was established to suit the purpose of estimating von Willebrand factor (VWF) levels in the plasma sample. The latex agglutination test can be performed qualitatively and semiquantitatively. Reproducibility, stability, linearity, limit of detection, interference, and method comparison studies were conducted to evaluate the performance of this test. Semiquantitative latex agglutination test was strongly correlated with the reference immunoturbidimetric assay (Spearman's rho = 0.946, P agglutination test and the reference assay. Using the scoring system for the rapid latex test, no agglutination is with 0% VWF : Ag (control negative), 1+ reaction is equivalent to 150% VWF : Ag (when comparing with immunoturbidimetric assay). The findings from evaluation studies suggest that latex agglutination method is suitable to be used as a rapid test kit for the estimation of VWF : Ag levels in various clinical conditions associated with high levels and low levels of VWF : Ag.

  16. A direct and rapid method to determine cyanide in urine by capillary electrophoresis.

    Science.gov (United States)

    Zhang, Qiyang; Maddukuri, Naveen; Gong, Maojun

    2015-10-02

    Cyanides are poisonous chemicals that widely exist in nature and industrial processes as well as accidental fires. Rapid and accurate determination of cyanide exposure would facilitate forensic investigation, medical diagnosis, and chronic cyanide monitoring. Here, a rapid and direct method was developed for the determination of cyanide ions in urinary samples. This technique was based on an integrated capillary electrophoresis system coupled with laser-induced fluorescence (LIF) detection. Cyanide ions were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) and a primary amine (glycine) for LIF detection. Three separate reagents, NDA, glycine, and cyanide sample, were mixed online, which secured uniform conditions between samples for cyanide derivatization and reduced the risk of precipitation formation of mixtures. Conditions were optimized; the derivatization was completed in 2-4min, and the separation was observed in 25s. The limit of detection (LOD) was 4.0nM at 3-fold signal-to-noise ratio for standard cyanide in buffer. The cyanide levels in urine samples from smokers and non-smokers were determined by using the method of standard addition, which demonstrated significant difference of cyanide levels in urinary samples from the two groups of people. The developed method was rapid and accurate, and is anticipated to be applicable to cyanide detection in waste water with appropriate modification. Published by Elsevier B.V.

  17. GSMA: Gene Set Matrix Analysis, An Automated Method for Rapid Hypothesis Testing of Gene Expression Data

    Directory of Open Access Journals (Sweden)

    Chris Cheadle

    2007-01-01

    Full Text Available Background: Microarray technology has become highly valuable for identifying complex global changes in gene expression patterns. The assignment of functional information to these complex patterns remains a challenging task in effectively interpreting data and correlating results from across experiments, projects and laboratories. Methods which allow the rapid and robust evaluation of multiple functional hypotheses increase the power of individual researchers to data mine gene expression data more efficiently.Results: We have developed (gene set matrix analysis GSMA as a useful method for the rapid testing of group-wise up- or downregulation of gene expression simultaneously for multiple lists of genes (gene sets against entire distributions of gene expression changes (datasets for single or multiple experiments. The utility of GSMA lies in its flexibility to rapidly poll gene sets related by known biological function or as designated solely by the end-user against large numbers of datasets simultaneously.Conclusions: GSMA provides a simple and straightforward method for hypothesis testing in which genes are tested by groups across multiple datasets for patterns of expression enrichment.

  18. Colorimetric stack pad immunoassay for bacterial identification.

    Science.gov (United States)

    Eltzov, Evgeni; Marks, Robert S

    2017-01-15

    A new colorimetric immunoassay concept, utilizing conventional lateral flow membranes (e.g., conjugation, sample, absorption and nitrocellulose), were placed in a different configuration in a stacking manner, where the liquid sample that may contain the analyte diffuses from the bottom to the upper-most layer. The key element of this proprietary technology is a capture layer, where a nitrocellulose membrane is modified with the target analyte of interest, namely in this study target Escherichia coli. During the immunoassay operation, samples contaminated with the target bacteria will conjugate to their corresponding HRP-antibodies laying in wait and the immune-target measurand complex flows by capillarity towards the upper-most layer to generate a colorimetric signal (positive answer) through an enzymatic reaction. In target-free samples, previously immobilized target bacteria on the capture layer will prevent the HRP-labeled anti-target antibodies from migrating to the upper-most layer, where the enzymatic substrate lays in wait. After optimization, the sensitivity of this approach was found to be 1,000 folds higher than ELISAs (102cellsmL-1). The advantages of the stacked pad assay include: miniaturization, operational simplicity, fast response time (less than 5min), useful sensitivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Interactive Rapid Dose Assessment Model (IRDAM): reactor-accident assessment methods. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Poeton, R.W.; Moeller, M.P.; Laughlin, G.J.; Desrosiers, A.E.

    1983-05-01

    As part of the continuing emphasis on emergency preparedness, the US Nuclear Regulatory Commission (NRC) sponsored the development of a rapid dose assessment system by Pacific Northwest Laboratory (PNL). This system, the Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program for rapidly assessing the radiological impact of accidents at nuclear power plants. This document describes the technical bases for IRDAM including methods, models and assumptions used in calculations. IRDAM calculates whole body (5-cm depth) and infant thyroid doses at six fixed downwind distances between 500 and 20,000 meters. Radionuclides considered primarily consist of noble gases and radioiodines. In order to provide a rapid assessment capability consistent with the capacity of the Osborne-1 computer, certain simplifying approximations and assumptions are made. These are described, along with default values (assumptions used in the absence of specific input) in the text of this document. Two companion volumes to this one provide additional information on IRDAM. The user's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Scenarios for Comparing Dose Assessment Models (NUREG/CR-3012, Volume 3) provides the results of calculations made by IRDAM and other models for specific accident scenarios.

  20. Comparison of concentration methods for rapid detection of hookworm ova in wastewater matrices using quantitative PCR.

    Science.gov (United States)

    Gyawali, P; Ahmed, W; Jagals, P; Sidhu, J P S; Toze, S

    2015-12-01

    Hookworm infection contributes around 700 million infections worldwide especially in developing nations due to increased use of wastewater for crop production. The effective recovery of hookworm ova from wastewater matrices is difficult due to their low concentrations and heterogeneous distribution. In this study, we compared the recovery rates of (i) four rapid hookworm ova concentration methods from municipal wastewater, and (ii) two concentration methods from sludge samples. Ancylostoma caninum ova were used as surrogate for human hookworm (Ancylostoma duodenale and Necator americanus). Known concentration of A. caninum hookworm ova were seeded into wastewater (treated and raw) and sludge samples collected from two wastewater treatment plants (WWTPs) in Brisbane and Perth, Australia. The A. caninum ova were concentrated from treated and raw wastewater samples using centrifugation (Method A), hollow fiber ultrafiltration (HFUF) (Method B), filtration (Method C) and flotation (Method D) methods. For sludge samples, flotation (Method E) and direct DNA extraction (Method F) methods were used. Among the four methods tested, filtration (Method C) method was able to recover higher concentrations of A. caninum ova consistently from treated wastewater (39-50%) and raw wastewater (7.1-12%) samples collected from both WWTPs. The remaining methods (Methods A, B and D) yielded variable recovery rate ranging from 0.2 to 40% for treated and raw wastewater samples. The recovery rates for sludge samples were poor (0.02-4.7), although, Method F (direct DNA extraction) provided 1-2 orders of magnitude higher recovery rate than Method E (flotation). Based on our results it can be concluded that the recovery rates of hookworm ova from wastewater matrices, especially sludge samples, can be poor and highly variable. Therefore, choice of concentration method is vital for the sensitive detection of hookworm ova in wastewater matrices. Crown Copyright © 2015. Published by Elsevier

  1. Rapid Determination of Isomeric Benzoylpaeoniflorin and Benzoylalbiflorin in Rat Plasma by LC-MS/MS Method

    Directory of Open Access Journals (Sweden)

    Chuanqi Zhou

    2017-01-01

    Full Text Available Benzoylpaeoniflorin (BP is a potential therapeutic agent against oxidative stress related Alzheimer’s disease. In this study, a more rapid, selective, and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS method was developed to determine BP in rat plasma distinguishing with a monoterpene isomer, benzoylalbiflorin (BA. The method showed a linear response from 1 to 1000 ng/mL (r>0.9950. The precision of the interday and intraday ranged from 2.03 to 12.48% and the accuracy values ranged from −8.00 to 10.33%. Each running of the method could be finished in 4 minutes. The LC-MS/MS method was validated for specificity, linearity, precision, accuracy, recovery, and stability and was found to be acceptable for bioanalytical application. Finally, this fully validated method was successfully applied to a pharmacokinetic study in rats following oral administration.

  2. Multifrequency excitation method for rapid and accurate dynamic test of micromachined gyroscope chips.

    Science.gov (United States)

    Deng, Yan; Zhou, Bin; Xing, Chao; Zhang, Rong

    2014-10-17

    A novel multifrequency excitation (MFE) method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE) method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes.

  3. Multifrequency Excitation Method for Rapid and Accurate Dynamic Test of Micromachined Gyroscope Chips

    Directory of Open Access Journals (Sweden)

    Yan Deng

    2014-10-01

    Full Text Available A novel multifrequency excitation (MFE method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes.

  4. A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa

    Science.gov (United States)

    Matsumoto, Yoshimi; Grushnikov, Andrey; Kikuchi, Kazuma; Noji, Hiroyuki; Yamaguchi, Akihito; Yagi, Yasushi

    2016-01-01

    The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM) device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller–Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation. PMID:26872134

  5. A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Yoshimi Matsumoto

    Full Text Available The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller-Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation.

  6. Adjustment of a rapid method for quantification of Fusarium spp. spore suspensions in plant pathology.

    Science.gov (United States)

    Caligiore-Gei, Pablo F; Valdez, Jorge G

    2015-01-01

    The use of a Neubauer chamber is a broadly employed method when cell suspensions need to be quantified. However, this technique may take a long time and needs trained personnel. Spectrophotometry has proved to be a rapid, simple and accurate method to estimate the concentration of spore suspensions of isolates of the genus Fusarium. In this work we present a linear formula to relate absorbance measurements at 530nm with the number of microconidia/ml in a suspension. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Rapid method for protein quantitation by Bradford assay after elimination of the interference of polysorbate 80.

    Science.gov (United States)

    Cheng, Yongfeng; Wei, Haiming; Sun, Rui; Tian, Zhigang; Zheng, Xiaodong

    2016-02-01

    Bradford assay is one of the most common methods for measuring protein concentrations. However, some pharmaceutical excipients, such as detergents, interfere with Bradford assay even at low concentrations. Protein precipitation can be used to overcome sample incompatibility with protein quantitation. But the rate of protein recovery caused by acetone precipitation is only about 70%. In this study, we found that sucrose not only could increase the rate of protein recovery after 1 h acetone precipitation, but also did not interfere with Bradford assay. So we developed a method for rapid protein quantitation in protein drugs even if they contained interfering substances. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Comparison of the NIDS® rapid assay with ELISA methods in immunogenicity testing of two biotherapeutics.

    Science.gov (United States)

    Pan, Jing; Small, Thomas; Qin, Dujie; Li, Shawn; Wang, Li; Chen, Dave; Pauley, Cindy; Verch, Thorsten; Kaplanski, Catherine; Bakhtiar, Ray; Vallejo, Yli Remo; Yin, Ray

    2011-01-01

    Rapid lateral flow immunogenicity assays for the detection of anti-drug antibodies (ADAs) to two biotherapeutic antibodies, an anti-HER2 antibody and an anti-TNF-α antibody, were developed using ANP Technologies, Inc.'s proprietary Nano-Intelligent Detection System (NIDS®) and compared to their ELISA counterparts. Biotin and hapten-labeled drugs are incubated with the patient serum sample to allow ADA to form a bridge complex with each drug conjugate. The reaction mixture is then added to a test strip with an anti-hapten capture zone which captures the mixed bridge complex. The bridge-complexed biotinylated drug then reacts with streptavidin-labeled gold particles in situ. The signal developed at the capture zone, which is directly proportional to ADA in the sample, is then quantitatively measured with a handheld reader. The counterpart ELISAs were run using the same reagents. Dose-response, specificity/free drug depletion, and screening cut-point assays were performed using both methods. The rapid assays' performance compare very closely to their ELISA counterparts'. Both types of assays identified the same positive samples in screening a limited population of 50 normal serum samples for the anti-HER2 antibody. In the case of anti-TNF-α, both assays identified the same positive samples out of 50 normal and 20 rheumatoid arthritis patient serum samples but differed in the assessment of two others. The rapid assay correctly identified as negative an ELISA false positive sample, and correctly tested as positive an ELISA false negative sample. Positive results were verified with a specificity/free drug depletion assay. The NIDS® rapid immunogenicity assay offers distinct advantages over current methods in simplicity, low cost, and short time to result. More importantly, the method requires no sample dilution and no washing steps which can perturb fragile complexes formed by low-affinity ADAs. Thus, the assay can potentially detect ADAs with various affinities

  9. A novel rapid and reproducible flow cytometric method for optimization of transfection efficiency in cells

    Science.gov (United States)

    Homann, Stefanie; Hofmann, Christian; Gorin, Aleksandr M.; Nguyen, Huy Cong Xuan; Huynh, Diana; Hamid, Phillip; Maithel, Neil; Yacoubian, Vahe; Mu, Wenli; Kossyvakis, Athanasios; Sen Roy, Shubhendu; Yang, Otto Orlean

    2017-01-01

    Transfection is one of the most frequently used techniques in molecular biology that is also applicable for gene therapy studies in humans. One of the biggest challenges to investigate the protein function and interaction in gene therapy studies is to have reliable monospecific detection reagents, particularly antibodies, for all human gene products. Thus, a reliable method that can optimize transfection efficiency based on not only expression of the target protein of interest but also the uptake of the nucleic acid plasmid, can be an important tool in molecular biology. Here, we present a simple, rapid and robust flow cytometric method that can be used as a tool to optimize transfection efficiency at the single cell level while overcoming limitations of prior established methods that quantify transfection efficiency. By using optimized ratios of transfection reagent and a nucleic acid (DNA or RNA) vector directly labeled with a fluorochrome, this method can be used as a tool to simultaneously quantify cellular toxicity of different transfection reagents, the amount of nucleic acid plasmid that cells have taken up during transfection as well as the amount of the encoded expressed protein. Finally, we demonstrate that this method is reproducible, can be standardized and can reliably and rapidly quantify transfection efficiency, reducing assay costs and increasing throughput while increasing data robustness. PMID:28863132

  10. A Rapid and Economical Method for Efficient DNA Extraction from Diverse Soils Suitable for Metagenomic Applications

    Science.gov (United States)

    Devi, Selvaraju Gayathri; Fathima, Anwar Aliya; Radha, Sudhakar; Arunraj, Rex; Curtis, Wayne R.; Ramya, Mohandass

    2015-01-01

    A rapid, cost effective method of metagenomic DNA extraction from soil is a useful tool for environmental microbiology. The present work describes an improved method of DNA extraction namely “powdered glass method” from diverse soils. The method involves the use of sterile glass powder for cell lysis followed by addition of 1% powdered activated charcoal (PAC) as purifying agent to remove humic substances. The method yielded substantial DNA (5.87 ± 0.04 μg/g of soil) with high purity (A260/280: 1.76 ± 0.05) and reduced humic substances (A340: 0.047 ± 0.03). The quality of the extracted DNA was compared against five different methods based on 16S rDNA PCR amplification, BamHI digestion and validated using quantitative PCR. The digested DNA was used for a metagenomic library construction with the transformation efficiency of 4 X 106 CFU mL-1. Besides providing rapid, efficient and economical extraction of metgenomic DNA from diverse soils, this method’s applicability is also demonstrated for cultivated organisms (Gram positive B. subtilis NRRL-B-201, Gram negative E. coli MTCC40, and a microalgae C. sorokiniana UTEX#1666). PMID:26167854

  11. New modelling method for fast reactor neutronic behaviours analysis; Nouvelles methodes de modelisation neutronique des reacteurs rapides de quatrieme Generation

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, P.

    2011-05-23

    Due to safety rules running on fourth generation reactors' core development, neutronics simulation tools have to be as accurate as never before. First part of this report enumerates every step of fast reactor's neutronics simulation implemented in current reference code: ECCO. Considering the field of fast reactors that meet criteria of fourth generation, ability of models to describe self-shielding phenomenon, to simulate neutrons leakage in a lattice of fuel assemblies and to produce representative macroscopic sections is evaluated. The second part of this thesis is dedicated to the simulation of fast reactors' core with steel reflector. These require the development of advanced methods of condensation and homogenization. Several methods are proposed and compared on a typical case: the ZONA2B core of MASURCA reactor. (author) [French] Les criteres de surete qui regissent le developpement de coeurs de reacteurs de quatrieme generation implique l'usage d'outils de calcul neutronique performants. Une premiere partie de la these reprend toutes les etapes de modelisation neutronique des reacteurs rapides actuellement d'usage dans le code de reference ECCO. La capacite des modeles a decrire le phenomene d'autoprotection, a representer les fuites neutroniques au niveau d'un reseau d'assemblages combustibles et a generer des sections macroscopiques representatives est appreciee sur le domaine des reacteurs rapides innovants respectant les criteres de quatrieme generation. La deuxieme partie de ce memoire se consacre a la modelisation des coeurs rapides avec reflecteur acier. Ces derniers necessitent le developpement de methodes avancees de condensation et d'homogenisation. Plusieurs methodes sont proposees et confrontees sur un probleme de modelisation typique: le coeur ZONA2B du reacteur maquette MASURCA

  12. Antioxidant properties of Krebs cycle intermediates against malonate pro-oxidant activity in vitro: a comparative study using the colorimetric method and HPLC analysis to determine malondialdehyde in rat brain homogenates.

    Science.gov (United States)

    Puntel, Robson Luiz; Roos, Daniel Henrique; Grotto, Denise; Garcia, Solange C; Nogueira, Cristina Wayne; Rocha, Joao Batista Teixeira

    2007-06-13

    A variety of Krebs cycle intermediaries has been shown to possess antioxidant properties in different in vivo and in vitro systems. Here we examined whether citrate, succinate, malate, oxaloacetate, fumarate and alpha-ketoglutarate could modulate malonate-induced thiobarbituric acid-reactive species (TBARS) production in rat brain homogenate. The mechanisms involved in their antioxidant activity were also determined using two analytical methods: 1) a popular spectrophotometric method (Ohkawa, H., Ohishi, N., Yagi, K., 1979. Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction. Analytical Biochemistry 95, 351-358.) and a high performance liquid chromatographic (HPLC) procedure (Grotto, D., Santa Maria, L. D., Boeira, S., Valentini, J., Charão, M. F., Moro, A. M., Nascimento, P. C., Pomblum, V. J., Garcia, S. C., 2006. Rapid quantification of malondialdehyde in plasma by high performance liquid chromatography-visible detection. Journal of Pharmaceutical and Biomedical Analysis 43, 619-624.). Citrate, malate, and oxaloacetate reduced both basal and malonate-induced TBARS production. Their effects were not changed by pre-treatment of rat brain homogenates at 100 degrees C for 10 min. alpha-Ketoglutarate increased basal TBARS without changing malonate-induced TBARS production in fresh and heat-treated homogenates. Succinate reduced basal--without altering malonate-induced TBARS production. Its antioxidant activity was abolished by KCN or heat treatment. Fumarate reduced malonate-induced TBARS production in fresh homogenates; however, its effect was completely abolished by heat treatment. There were minimal differences among the studied methods. Citrate, oxaloacetate, malate, alpha-ketoglutarate and malonate showed iron-chelating activity. We suggest that antioxidant properties of citrate, malate and oxaloacetate were due to their ability to cancel iron redox activity by forming inactive complexes, whereas alpha-ketoglutarate and malonate pro

  13. A rapid Salmonella detection method involving thermophilic helicase-dependent amplification and a lateral flow assay.

    Science.gov (United States)

    Du, Xin-Jun; Zhou, Tian-Jiao; Li, Ping; Wang, Shuo

    2017-08-01

    Salmonella is a major foodborne pathogen that is widespread in the environment and can cause serious human and animal disease. Since conventional culture methods to detect Salmonella are time-consuming and laborious, rapid and accurate techniques to detect this pathogen are critically important for food safety and diagnosing foodborne illness. In this study, we developed a rapid, simple and portable Salmonella detection strategy that combines thermophilic helicase-dependent amplification (tHDA) with a lateral flow assay to provide a detection result based on visual signals within 90 min. Performance analyses indicated that the method had detection limits for DNA and pure cultured bacteria of 73.4-80.7 fg and 35-40 CFU, respectively. Specificity analyses showed no cross reactions with Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Enterobacter aerogenes, Shigella and Campylobacter jejuni. The results for detection in real food samples showed that 1.3-1.9 CFU/g or 1.3-1.9 CFU/mL of Salmonella in contaminated chicken products and infant nutritional cereal could be detected after 2 h of enrichment. The same amount of Salmonella in contaminated milk could be detected after 4 h of enrichment. This tHDA-strip can be used for the rapid detection of Salmonella in food samples and is particularly suitable for use in areas with limited equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Rapid methods to detect organic mercury and total selenium in biological samples

    Directory of Open Access Journals (Sweden)

    Basu Niladri

    2011-01-01

    Full Text Available Abstract Background Organic mercury (Hg is a global pollutant of concern and selenium is believed to afford protection against mercury risk though few approaches exist to rapidly assess both chemicals in biological samples. Here, micro-scale and rapid methods to detect organic mercury ( Results For organic Hg, samples are digested using Tris-HCl buffer (with sequential additions of protease, NaOH, cysteine, CuSO4, acidic NaBr followed by extraction with toluene and Na2S2O3. The final product is analyzed via commercially available direct/total mercury analyzers. For Se, a fluorometric assay has been developed for microplate readers that involves digestion (HNO3-HClO4 and HCl, conjugation (2,3-diaminonaphthalene, and cyclohexane extraction. Recovery of organic Hg (86-107% and Se (85-121% were determined through use of Standard Reference Materials and lemon shark kidney tissues. Conclusions The approaches outlined provide an easy, rapid, reproducible, and cost-effective platform for monitoring organic Hg and total Se in biological samples. Owing to the importance of organic Hg and Se in the pathophysiology of Hg, integration of such methods into established research monitoring efforts (that largely focus on screening total Hg only will help increase understanding of Hg's true risks.

  15. Application of a colorimetric technique in quality control for printed pediatric orodispersible drug delivery systems containing propranolol hydrochloride

    DEFF Research Database (Denmark)

    Vakili, Hossein; Nyman, Johan O; Genina, Natalja

    2016-01-01

    hydrochloride in a colored ink base using three different edible substrates. A thin sweetener coating layer of saccharin was successfully included in the final dosage forms for palatability purposes using a casting knife. Optical microscopy, scanning electron microscopy and scanning white light interferometry......The feasibility of a colorimetric technique was investigated in CIELAB color space as an analytical quality control method for content uniformity of printed orodispersible pediatric delivery systems. Inkjet printing was utilized to fabricate orodispersibe film formulations containing propranolol....... to disintegrate within 180s. The colorimetric technique proved to be a reliable method to distinguish the small color differences between formulations containing an escalating dose of propranolol hydrochloride....

  16. Application of rapid cloud point extraction method for trace cobalt analysis coupled with spectrophotometric determination

    Science.gov (United States)

    Wen, Xiaodong; He, Lei; Shi, Chunsheng; Deng, Qingwen; Wang, Jiwei; Zhao, Xia

    2013-11-01

    In this work, the analytical performance of conventional spectrophotometer was improved through the coupling of effective preconcentration method with spectrophotometric determination. Rapidly synergistic cloud point extraction (RS-CPE) was used to pre-concentrate ultra trace cobalt and firstly coupled with spectrophotometric determination. The developed coupling was simple, rapid and efficient. The factors influencing RS-CPE and spectrophotometer were optimized. Under the optimal conditions, the limit of detection (LOD) was 0.6 μg L-1, with sensitivity enhancement factor of 23. The relative standard deviation (RSD) for seven replicate measurements of 50 μg L-1 of cobalt was 4.3%. The recoveries for the spiked samples were in the acceptable range of 93.8-105%.

  17. A rapid and direct real time PCR-based method for identification of Salmonella spp

    DEFF Research Database (Denmark)

    Rodriguez-Lazaro, D.; Hernández, Marta; Esteve, T.

    2003-01-01

    The aim of this work was the validation of a rapid, real-time PCR assay based on TaqMan((R)) technology for the unequivocal identification of Salmonella spp. to be used directly on an agar-grown colony. A real-time PCR system targeting at the Salmonella spp. invA gene was optimized and validated...... to be especially convenient because the pre-mix containing all PCR reagents except for the bacterial cells could be kept at -20 degreesC for at least I month before its use. The optimized TaqMan((R)) real-time PCR assay is a useful, simple and rapid method for routine identification of Salmonella spp...

  18. A rapid method for counting nucleated erythrocytes on stained blood smears by digital image analysis

    Science.gov (United States)

    Gering, E.; Atkinson, C.T.

    2004-01-01

    Measures of parasitemia by intraerythrocytic hematozoan parasites are normally expressed as the number of infected erythrocytes per n erythrocytes and are notoriously tedious and time consuming to measure. We describe a protocol for generating rapid counts of nucleated erythrocytes from digital micrographs of thin blood smears that can be used to estimate intensity of hematozoan infections in nonmammalian vertebrate hosts. This method takes advantage of the bold contrast and relatively uniform size and morphology of erythrocyte nuclei on Giemsa-stained blood smears and uses ImageJ, a java-based image analysis program developed at the U.S. National Institutes of Health and available on the internet, to recognize and count these nuclei. This technique makes feasible rapid and accurate counts of total erythrocytes in large numbers of microscope fields, which can be used in the calculation of peripheral parasitemias in low-intensity infections.

  19. [Three-Iindex-Value Method for Rapid Screening Unqualified Vegetable Oil].

    Science.gov (United States)

    He, Wen-xuan; Hong, Gui-shui; Fang, Run; Cai, Xian-chun; Huang, Sheng

    2015-04-01

    In the present study, by measuring the A3 005 (representing unsaturation), A985 (representing conjugated fatty acids), A960 + A985 (representing trans-fatty acid ) of southern common vegetable oils (peanut oil, corn oil, canola oil, soybean oil, sunflower oil, tea seed oil and olive oil), "waste oil" and overdue vegetable oils, the pass-setting-range of these three index values for the vegetable oils was obtained. On this basis, a method for rapid screening unqualified vegetable oil (expired, adding low-cost oil, adding "waste oil") was established. The method effectively improved the monitoring efficiency of vegetable oil. With this method of screening a number of suspected substandard oils were proved unqualified by determination of fatty acid composition and 11, 12, 13, 17 fatty acid content. Through the combination of several detection methods, the causes for disqualification of vegetable oils can be further inferred.

  20. New rapid DNA extraction method with Chelex from Venturia inaequalis spores.

    Science.gov (United States)

    Turan, Ceren; Nanni, Irene Maja; Brunelli, Agostino; Collina, Marina

    2015-08-01

    The objective of this study was to develop a rapid method to isolate DNA from Venturia inaequalis spores for use in diagnostic DNA mutation analysis. Chelex-100 resin was evaluated and compared with a well established DNA exctraction method, utilizing CTAB in order to have a robust comparison. In this research we demonstrated that Chelex-100 efficiently makes extraction of the DNA from V. inaequalis spores available for direct use in molecular analyses. Also, the quantity and quality of extracted DNA were shown to be adequate for PCR analysis. Comparatively, the quality of DNA samples isolated using Chelex method was better than those extracted using CTAB. In conclusion, the Chelex method is recommended for PCR experiments considering its simplicity and cost-effectiveness. Copyright © 2015. Published by Elsevier B.V.

  1. Rapid and sensitive liquid chromatography-mass spectrometry method for determination of ropinirole in human plasma.

    Science.gov (United States)

    Bhatt, Jignesh; Jangid, Arvind; Shetty, Raghavendra; Shah, Bhavin; Kambli, Sandeep; Subbaiah, Gunta; Singh, Sadhana

    2006-03-18

    A rapid and robust liquid chromatography-mass spectrometry (LC-MS/MS) method was developed for non-ergoline dopamine D(2)-receptor agonist, ropinirole in human plasma using Es-citalopram oxalate as an internal standard. The method involves solid phase extraction from plasma, reversed-phase simple isocratic chromatographic conditions and mass spectrometric detection that enables a detection limit at picogram levels. The proposed method was validated with linear range of 20-1,200 pg/ml. The extraction recoveries for ropinirole and internal standard were 90.45 and 65.42%, respectively. The R.S.D.% of intra-day and inter-day assay was lower than 15%. For its sensitivity and reliability, the proposed method is particularly suitable for pharmacokinetic studies.

  2. Simple and rapid methods for detecting Salmonella enteritidis in raw eggs.

    Science.gov (United States)

    Seo, Kun-Ho; Holt, Peter S; Stone, Henry D; Gast, Richard K

    2003-10-15

    The Centers for Disease Control and Prevention estimates there were 300,000 cases of Salmonella enteritidis (SE) in 1997. Egg products were associated with many of the cases. To address this problem, many producers implemented flock surveillance of the SE situation at their facilities. A rapid and simple method for detecting SE from poultry samples is critical for the effective implementation of such testing strategies. A lateral flow device for the detection of SE utilized in this study was manufactured by Neogen, Lansing, MI. The test panel is a presumptive qualitative test system that detects only members of Group D1 Salmonella species. A series of studies were conducted to optimize the test procedure for raw eggs with different sample preparations. A novel antigen extraction method was developed for use with the test panel kit. The detection limit of the test panel kit was increased approximately tenfold when the extraction method was used. Detection of SE was 100% in raw egg pools inoculated with 10 SE cells per ml of egg and incubated at a 1:10 ratio in buffered peptone water (BPW) or tetrathionate brilliant green broth (TBG) for 24 h at 37 degrees C. The developed lateral flow test kit could provide a simple, rapid, and inexpensive method for egg producers and processors to test specifically for Salmonella group D1 serovars, such as SE, in egg samples.

  3. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    Energy Technology Data Exchange (ETDEWEB)

    Pokorny, M.; Rebicek, J. [R& D Department, Contipro Biotech s.r.o., 561 02 Dolni Dobrouc (Czech Republic); Klemes, J. [R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic); Kotzianova, A. [R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic); Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno (Czech Republic); Velebny, V. [R& D Department, Contipro Biotech s.r.o., 561 02 Dolni Dobrouc (Czech Republic); R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic)

    2015-10-15

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  4. Rapid intrinsic fluorescence method for direct identification of pathogens in blood cultures.

    Science.gov (United States)

    Walsh, John D; Hyman, Jay M; Borzhemskaya, Larisa; Bowen, Ann; McKellar, Caroline; Ullery, Michael; Mathias, Erin; Ronsick, Christopher; Link, John; Wilson, Mark; Clay, Bradford; Robinson, Ron; Thorpe, Thurman; van Belkum, Alex; Dunne, W Michael

    2013-11-19

    A positive blood culture is a critical result that requires prompt identification of the causative agent. This article describes a simple method to identify microorganisms from positive blood culture broth within the time taken to perform a Gram stain (identification of the etiologic agent may benefit the clinical management of sepsis. Further evaluation is now warranted to determine the performance of the method using clinical blood culture specimens. Physicians often require the identity of the infective agent in order to make life-saving adjustments to empirical therapy or to switch to less expensive and/or more targeted antimicrobials. However, standard identification procedures take up to 2 days after a blood culture is signaled positive, and even most rapid molecular techniques take several hours to provide a result. Other techniques are faster (e.g., matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] mass spectrometry) but require time-consuming manual processing steps and expensive equipment. There remains a clear need for a simple, inexpensive method to rapidly identify microorganisms directly from positive blood cultures. The promising new method described in this research article can identify microorganisms in minutes by optical spectroscopy, thus permitting the lab to simultaneously report the presence of a positive blood culture and the organism's identity.

  5. Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality.

    Science.gov (United States)

    Green, Michael D; Nettey, Henry; Villalva Rojas, Ofelia; Pamanivong, Chansapha; Khounsaknalath, Lamphet; Grande Ortiz, Miguel; Newton, Paul N; Fernández, Facundo M; Vongsack, Latsamy; Manolin, Ot

    2007-01-04

    The proliferation of counterfeit and poor-quality drugs is a major public health problem; especially in developing countries lacking adequate resources to effectively monitor their prevalence. Simple and affordable field methods provide a practical means of rapidly monitoring drug quality in circumstances where more advanced techniques are not available. Therefore, we have evaluated refractometry, colorimetry and a technique combining both processes as simple and accurate field assays to rapidly test the quality of the commonly available antimalarial drugs; artesunate, chloroquine, quinine, and sulfadoxine. Method bias, sensitivity, specificity and accuracy relative to high-performance liquid chromatographic (HPLC) analysis of drugs collected in the Lao PDR were assessed for each technique. The HPLC method for each drug was evaluated in terms of assay variability and accuracy. The accuracy of the combined method ranged from 0.96 to 1.00 for artesunate tablets, chloroquine injectables, quinine capsules, and sulfadoxine tablets while the accuracy was 0.78 for enterically coated chloroquine tablets. These techniques provide a generally accurate, yet simple and affordable means to assess drug quality in resource-poor settings.

  6. A two-step method for rapid characterization of electroosmotic flows in capillary electrophoresis.

    Science.gov (United States)

    Zhang, Wenjing; He, Muyi; Yuan, Tao; Xu, Wei

    2017-12-01

    The measurement of electroosmotic flow (EOF) is important in a capillary electrophoresis (CE) experiment in terms of performance optimization and stability improvement. Although several methods exist, there are demanding needs to accurately characterize ultra-low electroosmotic flow rates (EOF rates), such as in coated capillaries used in protein separations. In this work, a new method, called the two-step method, was developed to accurately and rapidly measure EOF rates in a capillary, especially for measuring the ultra-low EOF rates in coated capillaries. In this two-step method, the EOF rates were calculated by measuring the migration time difference of a neutral marker in two consecutive experiments, in which a pressure driven was introduced to accelerate the migration and the DC voltage was reversed to switch the EOF direction. Uncoated capillaries were first characterized by both this two-step method and a conventional method to confirm the validity of this new method. Then this new method was applied in the study of coated capillaries. Results show that this new method is not only fast in speed, but also better in accuracy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Non-supervised method for early forest fire detection and rapid mapping

    Science.gov (United States)

    Artés, Tomás; Boca, Roberto; Liberta, Giorgio; San-Miguel, Jesús

    2017-09-01

    Natural hazards are a challenge for the society. Scientific community efforts have been severely increased assessing tasks about prevention and damage mitigation. The most important points to minimize natural hazard damages are monitoring and prevention. This work focuses particularly on forest fires. This phenomenon depends on small-scale factors and fire behavior is strongly related to the local weather. Forest fire spread forecast is a complex task because of the scale of the phenomena, the input data uncertainty and time constraints in forest fire monitoring. Forest fire simulators have been improved, including some calibration techniques avoiding data uncertainty and taking into account complex factors as the atmosphere. Such techniques increase dramatically the computational cost in a context where the available time to provide a forecast is a hard constraint. Furthermore, an early mapping of the fire becomes crucial to assess it. In this work, a non-supervised method for forest fire early detection and mapping is proposed. As main sources, the method uses daily thermal anomalies from MODIS and VIIRS combined with land cover map to identify and monitor forest fires with very few resources. This method relies on a clustering technique (DBSCAN algorithm) and on filtering thermal anomalies to detect the forest fires. In addition, a concave hull (alpha shape algorithm) is applied to obtain rapid mapping of the fire area (very coarse accuracy mapping). Therefore, the method leads to a potential use for high-resolution forest fire rapid mapping based on satellite imagery using the extent of each early fire detection. It shows the way to an automatic rapid mapping of the fire at high resolution processing as few data as possible.

  8. Interaction between Rivers and Aquifers: a method for rapid Identification of Transience in Streambed Conductance

    Science.gov (United States)

    Gianni, Guillaume; Perrochet, Pierre; Vogel, Alexandre; Brunner, Philip

    2016-04-01

    Streambed hydraulic conductance controls the interactions between surface water and groundwater. In order to quantify river-aquifer dynamics, quantifying conductance is indispensable. However, the streambed conductance is often subject to transience, as a result of the erosion and deposition processes in rivers. This transience has to be quantified and considered for any approach (i.e. numerical or analytical models) aimed at quantifying exchange fluxes. Directly measuring hydraulic properties in a river yields only point values, is time-consuming and therefore not suited to detect transience of the physical properties. We present a method to continuously and rapidly monitor transience of streambed conductance. Input data are time series of stream stage and hydraulic head variations in the aquifer. The method is based on the inversion of a floodwave response. The analytical model consists of only 3 parameters: x, the distance between streambank and an observation well, α, the aquifer diffusivity and a, the retardation coefficient that is inversely proportional to the streambed conductance. Estimation of a is carried out over successive time steps in order to identify transience in streambed conductance. The method is tested on synthetic data and is applied to field data from the Rhône River and its alluvial aquifer (Switzerland). The synthetic method demonstrated the robustness of the proposed methodology. Application of the method to the field site allowed identifying transience in streambed properties, following flood events in the Rhône. This method requires transience in the surface water, and the river should not change its width significantly with a rising water level. If these conditions are fulfilled, this method allows for a rapid and effective identification of transience of streambed conductance.

  9. The BUME method: a new rapid and simple chloroform-free method for total lipid extraction of animal tissue

    Science.gov (United States)

    Löfgren, Lars; Forsberg, Gun-Britt; Ståhlman, Marcus

    2016-06-01

    In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15-150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:ethyl acetate (3:1) and 500 μl 1% acetic acid a 5-minute two-phase extraction is performed. Lipids are recovered from the upper phase by automated liquid handling using a standard 96-tip robot. A second two-phase extraction is performed using 500 μl heptane:ethyl acetate (3:1). Validation of the method showed that the extraction recoveries for the investigated lipids, which included sterols, glycerolipids, glycerophospholipids and sphingolipids were similar or better than for the Folch method. We also applied the method for lipid extraction of liver and heart and compared the lipid species profiles with profiles generated after Folch and MTBE extraction. We conclude that the BUME method is superior to the Folch method in terms of simplicity, through-put, automation, solvent consumption, economy, health and environment yet delivering lipid recoveries fully comparable to or better than the Folch method.

  10. Rapid detection of carbapenemase production in Enterobacteriaceae using a modified paper strip Carba NP method.

    Science.gov (United States)

    Ho, Pak-Leung; Wang, Ya; Tse, Cindy Wing-Sze; Fung, Kitty Sau-Chun; Cheng, Vincent Ch-Chung; Lee, Rodney; To, Wing-Kin; Lai, Raymond Wai-Man; Luk, Wei-Kwang; Que, Tak-Lun; Tsang, Dominic Ngai-Chong

    2017-10-25

    Rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) is important for preventing their spread in healthcare settings. We compared the performance of the Carba NP test using the CLSI tube method with that using a modified paper strip method for detection of carbapenemase in 390 Enterobacteriaceae isolates. The isolates were identified by Hong Kong's carbapenem-resistant Enterobacteriaceae surveillance program in 2016 and comprised 213 CPE and 177 carbapenemase-negative Enterobacteriaceae Molecular genotype was used as the reference. Test results were read at different time points for the CLSI method (1 min, 5 min, 1 h and 2 h) and strip method (1 min, 5 min). The strip CNP and CLSI CNP tests correctly detect carbapenemase production in 93% and 93% KPC producers, 100% and 38% IMI producers, 94% and 85% IMP producers, 98% and 90% NDM producers, and, 29% and 12% OXA producers, respectively. Overall, the strip method has superior sensitivity than the CLSI method (86% vs. 75%, respectively, P NP test using the modified strip method has a higher sensitivity and a shorter assay time than using the CLSI tube method. Copyright © 2017 American Society for Microbiology.

  11. Rapid Staining Method to Detect and Identify Downy Mildew (Peronospora belbahrii in Basil

    Directory of Open Access Journals (Sweden)

    Adolfina R. Koroch

    2013-07-01

    Full Text Available Premise of the study: Demand for fresh-market sweet basil continues to increase, but in 2009 a new pathogen emerged, threatening commercial field/greenhouse production and leading to high crop losses. This study describes a simple and effective staining method for rapid microscopic detection of basil downy mildew (Peronospora belbahrii from leaves of basil (Ocimum basilicum. Methods and Results: Fresh leaf sections infected with P. belbahrii were placed on a microscope slide, cleared with Visikol™, and stained with iodine solution followed by one drop of 70% sulfuric acid. Cell walls of the pathogen were stained with a distinct coloration, providing a high-contrast image between the pathogen and plant. Conclusions: This new staining method can be used successfully to identify downy mildew in basil, which then can significantly reduce its spread if identified early, coupled with mitigation strategies. This technique can facilitate the control of the disease, without expensive and specialized equipment.

  12. The method of parallel-hierarchical transformation for rapid recognition of dynamic images using GPGPU technology

    Science.gov (United States)

    Timchenko, Leonid; Yarovyi, Andrii; Kokriatskaya, Nataliya; Nakonechna, Svitlana; Abramenko, Ludmila; Ławicki, Tomasz; Popiel, Piotr; Yesmakhanova, Laura

    2016-09-01

    The paper presents a method of parallel-hierarchical transformations for rapid recognition of dynamic images using GPU technology. Direct parallel-hierarchical transformations based on cluster CPU-and GPU-oriented hardware platform. Mathematic models of training of the parallel hierarchical (PH) network for the transformation are developed, as well as a training method of the PH network for recognition of dynamic images. This research is most topical for problems on organizing high-performance computations of super large arrays of information designed to implement multi-stage sensing and processing as well as compaction and recognition of data in the informational structures and computer devices. This method has such advantages as high performance through the use of recent advances in parallelization, possibility to work with images of ultra dimension, ease of scaling in case of changing the number of nodes in the cluster, auto scan of local network to detect compute nodes.

  13. Large Rapidity Gap Method to Select Soft Diffraction Dissociation at the LHC

    Directory of Open Access Journals (Sweden)

    Emily Nurse

    2016-01-01

    Full Text Available In proton-proton (pp collisions, any process involves exchanging the vacuum quantum numbers is known as diffractive process. A diffractive process with no large Q2 is called soft diffractive process. The diffractive processes are important for understanding nonperturbative QCD effects and they also constitute a significant fraction of the total pp cross section. The diffractive events are typically characterized by a region of the detector without particles, known as a rapidity gap. In order to observe diffractive events in this way, we consider the pseudorapidity acceptance in the forward region of the ATLAS and CMS detectors at the Large Hadron Collider (LHC and discuss the methods to select soft diffractive dissociation for pp collisions at s=7 TeV. It is shown that, in the limited detector rapidity acceptance, it is possible to select diffractive dissociation events by requiring a rapidity gap in the event; however, without using forward detectors, it seems not possible to fully separate single and double diffractive dissociation events. The Zero Degree Calorimeters can be used to distinguish the type of the diffractive processes up to a certain extent.

  14. Hierarchically rough, mechanically durable and superhydrophobic epoxy coatings through rapid evaporation spray method

    Energy Technology Data Exchange (ETDEWEB)

    Simovich, Tomer; Wu, Alex H.; Lamb, Robert N., E-mail: rnlamb@unimelb.edu.au

    2015-08-31

    A mechanically durable and scalable superhydrophobic coating was fabricated by combining the advantages of both bottom-up and top-down approaches into a one-pot, one-step application method. This is achieved by spray coating a solution consisting of silica nanoparticles, which are embedded within epoxy resin, onto a heated substrate to rapidly drive both solvent evaporation and curing simultaneously. By maintaining a high substrate temperature, the arrival of spray-delivered micrometer-sized droplets are rapidly cured onto the substrate to form surface microroughness, while simultaneously, rapid solvent evaporation within each droplet results in the formation of a nanoporous structure. SEM, dual-beam FIB, and cross-sectional TEM/EDAX elemental mapping were used to confirm both the chemistry and the requisite micro- and nano-porosity within the coating structure requisite for superhydrophobicity. The resultant coatings exhibit contact angles greater than 150° (153.8° ± 0.8°) and roll-off angles of 8° ± 2°, with a coating hardness of 6H on the pencil hardness scale, and a rating of 5 on an ASTM crosshatch test. - Highlights: • A highly superhydrophobic coating was fabricated utilizing epoxy and nanoparticles. • The coating was demonstrated to be very durable and abrasion resistant. • The fabrication involves a novel, scalable one-pot synthesis technique.

  15. Rapid Method for Ra-226 and Ra-228 in Water Samples

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod, L. III

    2006-02-10

    The measurement of radium isotopes in natural waters is important for oceanographic studies and for public health reasons. Ra-226 (1620 year half-life) is one of the most toxic of the long-lived alpha emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The analysis of radium-226 and radium-228 in natural waters can be tedious and time-consuming. Different sample preparation methods are often required to prepare Ra-226 and Ra-228 for separate analyses. A rapid method has been developed at the Savannah River Environmental Laboratory that effectively separates both Ra-226 and Ra-228 (via Ac-228) for assay. This method uses MnO{sub 2} Resin from Eichrom Technologies (Darien, IL, USA) to preconcentrate Ra-226 and Ra-228 rapidly from water samples, along with Ba-133 tracer. DGA Resin{reg_sign} (Eichrom) and Ln-Resin{reg_sign} (Eichrom) are employed in tandem to prepare Ra-226 for assay by alpha spectrometry and to determine Ra-228 via the measurement of Ac-228 by gas proportional counting. After preconcentration, the manganese dioxide is dissolved from the resin and passed through stacked Ln-Resin-DGA Resin cartridges that remove uranium and thorium interferences and retain Ac-228 on DGA Resin. The eluate that passed through this column is evaporated, redissolved in a lower acidity and passed through Ln-Resin again to further remove interferences before performing a barium sulfate microprecipitation. The Ac-228 is stripped from the resin, collected using cerium fluoride microprecipitation and counted by gas proportional counting. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

  16. A rapid and sensitive method for measuring N-acetylglucosaminidase activity in cultured cells.

    Directory of Open Access Journals (Sweden)

    Victor Mauri

    Full Text Available A rapid and sensitive method to quantitatively assess N-acetylglucosaminidase (NAG activity in cultured cells is highly desirable for both basic research and clinical studies. NAG activity is deficient in cells from patients with Mucopolysaccharidosis type IIIB (MPS IIIB due to mutations in NAGLU, the gene that encodes NAG. Currently available techniques for measuring NAG activity in patient-derived cell lines include chromogenic and fluorogenic assays and provide a biochemical method for the diagnosis of MPS IIIB. However, standard protocols require large amounts of cells, cell disruption by sonication or freeze-thawing, and normalization to the cellular protein content, resulting in an error-prone procedure that is material- and time-consuming and that produces highly variable results. Here we report a new procedure for measuring NAG activity in cultured cells. This procedure is based on the use of the fluorogenic NAG substrate, 4-Methylumbelliferyl-2-acetamido-2-deoxy-alpha-D-glucopyranoside (MUG, in a one-step cell assay that does not require cell disruption or post-assay normalization and that employs a low number of cells in 96-well plate format. We show that the NAG one-step cell assay greatly discriminates between wild-type and MPS IIIB patient-derived fibroblasts, thus providing a rapid method for the detection of deficiencies in NAG activity. We also show that the assay is sensitive to changes in NAG activity due to increases in NAGLU expression achieved by either overexpressing the transcription factor EB (TFEB, a master regulator of lysosomal function, or by inducing TFEB activation chemically. Because of its small format, rapidity, sensitivity and reproducibility, the NAG one-step cell assay is suitable for multiple procedures, including the high-throughput screening of chemical libraries to identify modulators of NAG expression, folding and activity, and the investigation of candidate molecules and constructs for applications in

  17. Rapid expansion method (REM) for time‐stepping in reverse time migration (RTM)

    KAUST Repository

    Pestana, Reynam C.

    2009-01-01

    We show that the wave equation solution using a conventional finite‐difference scheme, derived commonly by the Taylor series approach, can be derived directly from the rapid expansion method (REM). After some mathematical manipulation we consider an analytical approximation for the Bessel function where we assume that the time step is sufficiently small. From this derivation we find that if we consider only the first two Chebyshev polynomials terms in the rapid expansion method we can obtain the second order time finite‐difference scheme that is frequently used in more conventional finite‐difference implementations. We then show that if we use more terms from the REM we can obtain a more accurate time integration of the wave field. Consequently, we have demonstrated that the REM is more accurate than the usual finite‐difference schemes and it provides a wave equation solution which allows us to march in large time steps without numerical dispersion and is numerically stable. We illustrate the method with post and pre stack migration results.

  18. An evaluation of rapid methods for monitoring vegetation characteristics of wetland bird habitat

    Science.gov (United States)

    Tavernia, Brian G.; Lyons, James E.; Loges, Brian W.; Wilson, Andrew; Collazo, Jaime A.; Runge, Michael C.

    2016-01-01

    Wetland managers benefit from monitoring data of sufficient precision and accuracy to assess wildlife habitat conditions and to evaluate and learn from past management decisions. For large-scale monitoring programs focused on waterbirds (waterfowl, wading birds, secretive marsh birds, and shorebirds), precision and accuracy of habitat measurements must be balanced with fiscal and logistic constraints. We evaluated a set of protocols for rapid, visual estimates of key waterbird habitat characteristics made from the wetland perimeter against estimates from (1) plots sampled within wetlands, and (2) cover maps made from aerial photographs. Estimated percent cover of annuals and perennials using a perimeter-based protocol fell within 10 percent of plot-based estimates, and percent cover estimates for seven vegetation height classes were within 20 % of plot-based estimates. Perimeter-based estimates of total emergent vegetation cover did not differ significantly from cover map estimates. Post-hoc analyses revealed evidence for observer effects in estimates of annual and perennial covers and vegetation height. Median time required to complete perimeter-based methods was less than 7 percent of the time needed for intensive plot-based methods. Our results show that rapid, perimeter-based assessments, which increase sample size and efficiency, provide vegetation estimates comparable to more intensive methods.

  19. wzi Gene Sequencing, a Rapid Method for Determination of Capsular Type for Klebsiella Strains

    Science.gov (United States)

    Passet, Virginie; Haugaard, Anita Björk; Babosan, Anamaria; Kassis-Chikhani, Najiby; Struve, Carsten; Decré, Dominique

    2013-01-01

    Pathogens of the genus Klebsiella have been classified into distinct capsular (K) types for nearly a century. K typing of Klebsiella species still has important applications in epidemiology and clinical microbiology, but the serological method has strong practical limitations. Our objective was to evaluate the sequencing of wzi, a gene conserved in all capsular types of Klebsiella pneumoniae that codes for an outer membrane protein involved in capsule attachment to the cell surface, as a simple and rapid method for the prediction of K type. The sequencing of a 447-nucleotide region of wzi distinguished the K-type reference strains with only nine exceptions. A reference wzi sequence database was created by the inclusion of multiple strains representing K types associated with high virulence and multidrug resistance. A collection of 119 prospective clinical isolates of K. pneumoniae were then analyzed in parallel by wzi sequencing and classical K typing. Whereas K typing achieved typeability for 81% and discrimination for 94.4% of the isolates, these figures were 98.1% and 98.3%, respectively, for wzi sequencing. The prediction of K type once the wzi allele was known was 94%. wzi sequencing is a rapid and simple method for the determination of the K types of most K. pneumoniae clinical isolates. PMID:24088853

  20. A rapid method for measuring soil water content in the field with a areometer

    Directory of Open Access Journals (Sweden)

    Calbo Adonai Gimenez

    2002-01-01

    Full Text Available The availability of a rapid method to evaluate the soil water content (U can be an important tool to determine the moment to irrigate. The soil areometer consists of an elongated hydrostatic balance with a weighing pan, a graduated neck, a float and a pynometric flask. In this work an areometer was adapted to rapidly measure soil water content without the need of drying the soil. The expression U = (M A - M AD/(M M -M A was used to calculate the soil water content. In this equation M M is the mass to level the areometer with the pycnometric flask filled with water, M A the mass to level the areometer with a mass M M of soil in the pycnometer, the volume being completed with water, and similarly M AD the mass added to the pan to level the areometer with a mass M M of dried soil in the pycnometric flask. The convenience of this method is that the values M M and M AD are known. Consequently, the decision on irrigation can be made after a measurement that takes, about, ten minutes. The procedure involves only stirring the soil with water for at least 2 minutes to remove the adhered air. The soil water content data obtained with the areometric method were similar to those obtained weighing the soil before and after drying to constant weight, in an oven at 105º C.

  1. Single-step blood direct PCR: A robust and rapid method to diagnose triplet repeat disorders.

    Science.gov (United States)

    Singh, Inder; Swarup, Vishnu; Shakya, Sunil; Goyal, Vinay; Faruq, Mohammed; Srivastava, Achal Kumar

    2017-08-15

    DNA extraction prior to polymerase chain reaction (PCR) amplification in genetic diagnoses of triplet repeat disorders (TRDs) is tedious and labour-intensive and has the limitations of sample contamination with foreign DNA, including that from preceding samples. Therefore, we aimed to develop a rapid, robust, and cost-effective method for expeditious genetic investigation of TRDs from whole blood as a DNA template. Peripheral blood samples were collected from 70 clinically suspected patients of progressive ataxia. The conventional method using genomic DNA and single-step Blood-Direct PCR (BD-PCR) method with just 2μl of whole blood sample were tested to amplify triplet repeat expansion in genes related to spinocerebellar ataxia (SCA) types 1, 2, 3, 12 and Friedreich's ataxia (FRDA). Post-PCR, the allele sizes were mapped and repeat numbers were calculated using GeneMapper and macros run in Microsoft Excel programmes. Successful amplification of target regions was achieved in all samples by both methods. The frequency of the normal and mutated allele was concordant between both methods, diagnosing 37% positive for a mutation in either of the candidate genes. The BD-PCR resulted in higher intensities of product peaks of normal and pathogenic alleles. The nearly-accurate sizing of the normal and expanded allele was achieved in a shorter time (4-5h), without DNA extraction and any risk of cross contamination, which suggests the BD-PCR to be a reliable, inexpensive, and rapid method to confirm TRDs. This technique can be introduced in routine diagnostic procedures of other tandem repeat disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Combined Colorimetric and Gravimetric CMUT Sensor for Detection of Phenylacetone

    DEFF Research Database (Denmark)

    Mølgaard, Mathias Johannes Grøndahl; Laustsen, Milan; Thygesen, Ida Lysgaard

    2017-01-01

    The detection of phenylacetone is of interest as it is a common precursor for the synthesis of (meth)amphetamine. Resonant gravimetric sensors can be used to detect the mass and hereby the concentration of a gas while colorimetric arrays typically have an exceptional selectivity to the target...... analyte if the right colorimetric dyes are chosen. We present a sensor system consisting of a Capacitive Micromachined Ultrasonic Transducer (CMUT) and a colorimetric array for detection of phenylacetone. The CMUT is used as a resonant gravimetric gas sensor where the resonance frequency shift due to mass...

  3. Label-free colorimetric detection of cadmium ions in rice samples using gold nanoparticles.

    Science.gov (United States)

    Guo, Yongming; Zhang, Yi; Shao, Huawu; Wang, Zhuo; Wang, Xuefei; Jiang, Xingyu

    2014-09-02

    A simple and label-free colorimetric method for cadmium ions (Cd(2+)) detection using unmodified gold nanoparticles (AuNPs) is reported. The unmodified AuNPs easily aggregate in a high concentration of NaCl solution, but the presence of glutathione (GSH) can prevent the salt-induced aggregation of AuNPs. When Cd(2+) is added to the stable mixture of AuNPs, GSH, and NaCl, Cd(2+) can coordinate with 4× GSH as a spherical shaped complex, which decreases the amount of free GSH on the surface of gold nanoparticles to weaken the stability of AuNPs, and AuNPs will easily aggregate in high-salt conditions. On the basis of the mechanism, we design a simple, label-free colorimetric method using AuNPs accompanied by GSH in a high-salt environment to detect Cd(2+) in water and digested rice samples.

  4. Evaluation of the accuracy of the microplate Alamar Blue assay for rapid detection of MDR-TB in Peru.

    Science.gov (United States)

    Chauca, J A; Palomino, J-C; Guerra, H

    2007-07-01

    Tuberculosis control is hampered by the widespread increase in multidrug resistance. Rapid drug susceptibility testing would greatly aid in the adequate treatment of the disease. This study evaluates the usefulness of the colorimetric method using Alamar Blue for the rapid detection of resistance to rifampicin and isoniazid in 63 clinical isolates of Mycobacterium tuberculosis in Peru. Results obtained by receiver operating characteristic curve analysis and measures of gain in certainty showed greater diagnostic accuracy than with the gold standard, the proportion method on Löwenstein-Jensen medium.

  5. A Rapid Method for Determining the Concentration of Recombinant Protein Secreted from Pichia pastoris

    Science.gov (United States)

    Sun, L. W.; Zhao, Y.; Niu, L. P.; Jiang, R.; Song, Y.; Feng, H.; feng, K.; Qi, C.

    2011-02-01

    Pichia secretive expression system is one of powerful eukaryotic expression systems in genetic engineering, which is especially suitable for industrial utilization. Because of the low concentration of the target protein in initial experiment, the methods and conditions for expression of the target protein should be optimized according to the protein yield repetitively. It is necessary to set up a rapid, simple and convenient analysis method for protein expression levels instead of the generally used method such as ultrafiltration, purification, dialysis, lyophilization and so on. In this paper, acetone precipitation method was chosen to concentrate the recombinant protein firstly after comparing with four different protein precipitation methods systematically, and then the protein was analyzed by SDS-Polyacrylamide Gel Electrophoresis. The recombinant protein was determined with the feature of protein band by the Automated Image Capture and 1-D Analysis Software directly. With this method, the optimized expression conditions of basic fibroblast growth factor secreted from pichia were obtained, which is as the same as using traditional methods. Hence, a convenient tool to determine the optimized conditions for the expression of recombinant proteins in Pichia was established.

  6. Rapid Reticulin Fiber Staining Method is Helpful for the Diagnosis of Pituitary Adenoma in Frozen Section.

    Science.gov (United States)

    Noh, Songmi; Kim, Sun Ho; Cho, Nam Hoon; Kim, Se Hoon

    2015-05-01

    Approximately 90% of neoplasms found in the sellar region are adenoma of the pituitary gland. The use of frozen sections for the diagnosis of pituitary adenomas has an accuracy of 90% and is useful in evaluating complete tumor removal. However, it is sometimes difficult to diagnose pituitary adenomas using frozen sections because of the small sample size and marked artifact, and the contiguity of the pituitary adenoma with normal pituitary gland tissue. In this study, we evaluated the use of our modified reticulin stain to make correct decision in frozen section with reduced stain time and investigated the objective diagnostic criteria of pituitary adenoma with reticulin stain. We used Gomori's silver impregnation methods to stain reticulin fibers in frozen pituitary gland sections of 36 samples from 24 patients. We modified the conventional staining method by reducing the overall staining time. We diagnosed pituitary lesion according to our interpretation criteria and compared the results to those of the conventional method and findings of hematoxylin and eosin-stained slides. Reticulin fiber staining of normal adenohypophysis outlines the supporting stroma around the blood vessels and shows regular of the gland meshwork interconnecting the capillaries. In contrast, reticulin fiber staining of the adenomatous tissue shows loss of meshwork or frequent fragmentation. Our modified reticulin stain is more rapid than the established method and shows similar levels of accuracy. Independent evaluation by two pathologists showed discrepancies in diagnosis in four out of 36 cases with modified reticulin stain. Our rapid modified reticulin staining method for frozen sections may be useful as a diagnostic tool for pituitary adenomas and can complement routine hematoxylin and eosin staining.

  7. Clinical usefulness of multiplex PCR lateral flow in MRSA detection: a novel, rapid genetic testing method.

    Science.gov (United States)

    Nihonyanagi, Shin; Kanoh, Yuhsaku; Okada, Kiyomi; Uozumi, Toshiki; Kazuyama, Yukumasa; Yamaguchi, Tokiko; Nakazaki, Nobuhiko; Sakurai, Keizou; Hirata, Yasuyoshi; Munekata, Shinichi; Ohtani, Shinichi; Takemoto, Tsuyoshi; Bandoh, Yuki; Akahoshi, Tohru

    2012-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) with exogenous cassette DNA containing the methicillin-resistant gene mecA (SCCmec) poses a problem as a drug-resistant bacterium responsible for hospital- and community-acquired infections. The frequency of MRSA detection has recently been increasing rapidly in Japan, and SCCmec has also been classified more diversely into types I-V. A rapid test is essential for early diagnosis and treatment of MRSA infections, but detection by conventional methods requires at least two days. The newly developed multiplex PCR lateral flow method allows specific amplification of femA to detect S. aureus, mecA to detect SCCmec, and kdpC to detect SCCmec type II; moreover, PCR products can be evaluated visually in about 3 h. In the present study, we developed a PCR lateral flow method for MRSA using this method and investigated its clinical usefulness in the detection of MRSA. The results showed a diagnostic concordance rate of 91.7% for MRSA and methicillin-susceptible S. aureus between bacteriological examination and PCR lateral flow, and a high level of specificity in PCR lateral flow. In addition, a higher detection rate for S. aureus using the same sample was observed for PCR lateral flow (70.2%) than for bacteriological tests (48.6%). The above results show that PCR lateral flow for MRSA detection has high sensitivity, specificity, and speed, and its clinical application as a method for early diagnosis of MRSA infections appears to be feasible.

  8. Optimal estimation and scheduling in aquifer management using the rapid feedback control method

    Science.gov (United States)

    Ghorbanidehno, Hojat; Kokkinaki, Amalia; Kitanidis, Peter K.; Darve, Eric

    2017-12-01

    Management of water resources systems often involves a large number of parameters, as in the case of large, spatially heterogeneous aquifers, and a large number of "noisy" observations, as in the case of pressure observation in wells. Optimizing the operation of such systems requires both searching among many possible solutions and utilizing new information as it becomes available. However, the computational cost of this task increases rapidly with the size of the problem to the extent that textbook optimization methods are practically impossible to apply. In this paper, we present a new computationally efficient technique as a practical alternative for optimally operating large-scale dynamical systems. The proposed method, which we term Rapid Feedback Controller (RFC), provides a practical approach for combined monitoring, parameter estimation, uncertainty quantification, and optimal control for linear and nonlinear systems with a quadratic cost function. For illustration, we consider the case of a weakly nonlinear uncertain dynamical system with a quadratic objective function, specifically a two-dimensional heterogeneous aquifer management problem. To validate our method, we compare our results with the linear quadratic Gaussian (LQG) method, which is the basic approach for feedback control. We show that the computational cost of the RFC scales only linearly with the number of unknowns, a great improvement compared to the basic LQG control with a computational cost that scales quadratically. We demonstrate that the RFC method can obtain the optimal control values at a greatly reduced computational cost compared to the conventional LQG algorithm with small and controllable losses in the accuracy of the state and parameter estimation.

  9. Efficient 3D frequency response modeling with spectral accuracy by the rapid expansion method

    KAUST Repository

    Chu, Chunlei

    2012-07-01

    Frequency responses of seismic wave propagation can be obtained either by directly solving the frequency domain wave equations or by transforming the time domain wavefields using the Fourier transform. The former approach requires solving systems of linear equations, which becomes progressively difficult to tackle for larger scale models and for higher frequency components. On the contrary, the latter approach can be efficiently implemented using explicit time integration methods in conjunction with running summations as the computation progresses. Commonly used explicit time integration methods correspond to the truncated Taylor series approximations that can cause significant errors for large time steps. The rapid expansion method (REM) uses the Chebyshev expansion and offers an optimal solution to the second-order-in-time wave equations. When applying the Fourier transform to the time domain wavefield solution computed by the REM, we can derive a frequency response modeling formula that has the same form as the original time domain REM equation but with different summation coefficients. In particular, the summation coefficients for the frequency response modeling formula corresponds to the Fourier transform of those for the time domain modeling equation. As a result, we can directly compute frequency responses from the Chebyshev expansion polynomials rather than the time domain wavefield snapshots as do other time domain frequency response modeling methods. When combined with the pseudospectral method in space, this new frequency response modeling method can produce spectrally accurate results with high efficiency. © 2012 Society of Exploration Geophysicists.

  10. A new method for rapid determination of carbohydrate and total carbon concentrations using UV spectrophotometry.

    Science.gov (United States)

    Albalasmeh, Ammar A; Berhe, Asmeret Asefaw; Ghezzehei, Teamrat A

    2013-09-12

    A new UV spectrophotometry based method for determining the concentration and carbon content of carbohydrate solution was developed. This method depends on the inherent UV absorption potential of hydrolysis byproducts of carbohydrates formed by reaction with concentrated sulfuric acid (furfural derivatives). The proposed method is a major improvement over the widely used Phenol-Sulfuric Acid method developed by DuBois, Gilles, Hamilton, Rebers, and Smith (1956). In the old method, furfural is allowed to develop color by reaction with phenol and its concentration is detected by visible light absorption. Here we present a method that eliminates the coloration step and avoids the health and environmental hazards associated with phenol use. In addition, avoidance of this step was shown to improve measurement accuracy while significantly reducing waiting time prior to light absorption reading. The carbohydrates for which concentrations and carbon content can be reliably estimated with this new rapid Sulfuric Acid-UV technique include: monosaccharides, disaccharides and polysaccharides with very high molecular weight. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. A Simple and Rapid Data Extraction Method for the Precision Aspheric Optical Surface Height

    Science.gov (United States)

    Xing, Guohua; Peng, Yunfeng; Su, Xing

    2017-10-01

    Nowadays, the application of aspheric optics is becoming more and more popular in the precision optical engineering field. Therefore, it urges the rapid development of the precision machining and measuring technology. Generally, the aspheric optical component is measured by the interferometer. The underlying question is that the figure output by interferometer can’t be always recognized by other analysis software or program though the interferometer has its own unique data processing system. In this paper, a robust, rapid and simple method is presented to interpret the surface height data of the precision machined aspheric optical surface. The optical surface is measured by interferometer. The result figure is split into two parts, one of which is the interferogram picture of the whole aspheric optical surface and the other is the colour reference column indicating the height value. The ratios of the red (R), green (G) and blue (B) are analysed based on the middle of the colour reference column, and the corresponding relationship between the colours and surface height is established and looked as a reference data base. Then the interferogram picture of the whole aspheric optical surface is also analysed and divided according to the red (R), green (G) and blue (B) colours. By comparing the ratios and values of RGB colour, the aspheric optical surface height can be extracted approximately. The feasibility of this method was approved by the extraction processing experiment of a polished aspheric optical surface.

  12. A rapid, highly accurate method for quantifying CALR mutant allele burden in persons with myeloproliferative neoplasms.

    Science.gov (United States)

    Yao, Qiu-Mei; Zhou, Jiao; Gale, Robert Peter; Li, Jin-Lan; Li, Ling-Di; Li, Ning; Chen, Shan-Shan; Ruan, Guo-Rui

    2015-10-01

    Calreticulin (CALR) mutations were recently identified in a substantial proportion of persons with essential thrombocythemia (ET) and with primary myelofibrosis (PMF) without JAK2(V617F). Consequently rapid, sensitive, and specific methods to detect and quantify these mutations are needed. We studied samples from 1088 persons with myeloproliferative neoplasms (MPNs) including 421 JAK2(V617F) negative subjects with ET, PMF, polycythemia vera (PV), chronic myeloid leukemia (CML) and hyper-eosinophilic syndrome (HES). Detection of CALR exon 9 mutations was done by PCR amplification followed by fragment length analysis and direct sequencing. Dilution assays were used to determine CALR mutant allele burden. We detected CALR mutations in blood and bone marrow samples from 152 subjects with ET and with PMF but not in samples from normal or persons with PV, CML, or HES. CALR mutant peaks were distinct from wild-type peaks and dilution experiments indicated a sensitivity level of 0.5-5% for a CALR mutant allele in a wild-type background. Diverse types of mutations were detected including deletions, insertions, and complex indels. All mutations were confirmed by direct sequencing. We also used dilution experiments to quantify mutant allele burden. We were able to reproducibly detect mutant allele levels as low 5% (0.5-5%) in a wild-type background. PCR amplification followed by fragment length analysis is a rapid, sensitive, and specific method for screening persons with MPNs for CALR mutations, especially those with ET and PMF and for estimating mutant allele burden.

  13. Rapid fabrication method of a microneedle mold with controllable needle height and width.

    Science.gov (United States)

    Lin, Yen-Heng; Lee, I-Chi; Hsu, Wei-Chieh; Hsu, Ching-Hong; Chang, Kai-Ping; Gao, Shao-Syuan

    2016-10-01

    The main issue of transdermal drug delivery is that macromolecular drugs cannot diffuse through the stratum corneum of skin. Many studies have pursued micro-sized needles encapsulated with drugs to overcome this problem, as these needles can pierce the stratum corneum and allow drugs to enter the circulatory system of the human body. However, most microneedle fabrication processes are time-consuming and require expensive equipment. In this study, we demonstrate a rapid method for fabricating a microneedle mold using drawing lithography and a UV-cured resin. The mold was filled with a water-soluble material, polyvinylpyrrolidone (PVP), which was then demolded to produce a water-soluble microneedle array. The results of an in vitro skin insertion test using PVP microneedles and pig ear skin demonstrated the feasibility of the microneedle mold. In addition, by controlling the viscosity of the UV-cured resin through various heat treatments, microneedles with different heights and aspect ratios were produced. Compared with other methods, this technology significantly simplifies and accelerates the mold fabrication process. In addition, the required equipment is relatively simple and inexpensive. Through this technology, we can rapidly fabricate microneedle molds with controllable dimensions for various applications.

  14. Passive acoustic methods for fine-scale tracking of harbour porpoises in tidal rapids.

    Science.gov (United States)

    Macaulay, Jamie; Gordon, Jonathan; Gillespie, Douglas; Malinka, Chloë; Northridge, Simon

    2017-02-01

    The growing interest in generating electrical power from tidal currents using tidal turbine generators raises a number of environmental concerns, including the risk that marine mammals might be injured or killed through collision with rotating turbine blades. To understand this risk, information on how marine mammals use tidal rapid habitats and in particular, their underwater movements and dive behaviour is required. Porpoises, which are the most abundant small cetacean at most European tidal sites, are difficult animals to tag, and the limited size of tidal habitats means that any telemetered animal would be likely to spend only a small proportion of time within them. Here, an alternative approach is explored, whereby passive acoustic monitoring (PAM) is used to obtain fine scale geo-referenced tracks of harbour porpoises in tidal rapid areas. Large aperture hydrophone arrays are required to obtain accurate locations of animals from PAM data and automated algorithms are necessary to process the large quantities of acoustic data collected on such systems during a typical survey. Methods to automate localisation, including a method to match porpoise detections on different hydrophones and separate different vocalising animals, and an assessment of the localisation accuracy of the large aperture hydrophone array are presented.

  15. Miniaturized fluorescent RNA dot blot method for rapid quantitation of gene expression

    Directory of Open Access Journals (Sweden)

    Yadetie Fekadu

    2004-06-01

    Full Text Available Abstract Background RNA dot blot hybridization is a commonly used technique for gene expression assays. However, membrane based RNA dot/slot blot hybridization is time consuming, requires large amounts of RNA, and is less suited for parallel assays of more than one gene at a time. Here, we describe a glass-slide based miniaturized RNA dot blot (RNA array procedure for rapid and parallel gene expression analysis using fluorescently labeled probes. Results RNA arrays were prepared by simple manual spotting of RNA onto amino-silane coated microarray glass slides, and used for two-color fluorescent hybridization with specific probes labeled with Cy3 and 18S ribosomal RNA house-keeping gene probe labeled with Cy5 fluorescent dyes. After hybridization, arrays were scanned on a fluorescent microarray scanner and images analyzed using microarray image analysis software. We demonstrate that this method gives comparable results to Northern blot analysis, and enables high throughput quantification of transcripts from nanogram quantities of total RNA in hundreds of samples. Conclusion RNA array on glass slide and detection by fluorescently labeled probes can be used for rapid and parallel gene expression analysis. The method is particularly well suited for gene expression assays that involve quantitation of many transcripts in large numbers of samples.

  16. Hyperspectral Imaging as a Rapid Quality Control Method for Herbal Tea Blends

    Directory of Open Access Journals (Sweden)

    Majolie Djokam

    2017-03-01

    Full Text Available In South Africa, indigenous herbal teas are enjoyed due to their distinct taste and aroma. The acclaimed health benefits of herbal teas include the management of chronic diseases such as hypertension and diabetes. Quality control of herbal teas has become important due to the availability of different brands of varying quality and the production of tea blends. The potential of hyperspectral imaging as a rapid quality control method for herbal tea blends from rooibos (Aspalathus linearis, honeybush (Cyclopia intermedia, buchu (Agathosma Betulina and cancerbush (Sutherlandia frutescens was investigated. Hyperspectral images of raw materials and intact tea bags were acquired using a sisuChema shortwave infrared (SWIR hyperspectral pushbroom imaging system (920–2514 nm. Principal component analysis (PCA plots showed clear discrimination between raw materials. Partial least squares discriminant analysis (PLS-DA models correctly predicted the raw material constituents of each blend and accurately determined the relative proportions. The results were corroborated independently using ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS. This study demonstrated the application of hyperspectral imaging coupled with chemometric modelling as a reliable, rapid and non-destructive quality control method for authenticating herbal tea blends and to determine relative proportions in a tea bag.

  17. Rapid and label-free bioanalytical method of alpha fetoprotein detection using LSPR chip

    Science.gov (United States)

    Kim, Dongjoo; Kim, Jinwoon; Kwak, Cheol Hwan; Heo, Nam Su; Oh, Seo Yeong; Lee, Hoomin; Lee, Go-Woon; Vilian, A. T. Ezhil; Han, Young-Kyu; Kim, Woo-Sik; Kim, Gi-bum; Kwon, Soonjo; Huh, Yun Suk

    2017-07-01

    Alpha fetoprotein (AFP) is a cancer marker, particularly for hepatocellular carcinoma. Normal levels of AFP are less than 20 ng/mL; however, its levels can reach more than 400 ng/mL in patients with HCC. Enzyme linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) have been employed for clinical diagnosis of AFP; however, these methods are time consuming and labor intensive. In this study, we developed a localized surface plasmon resonance (LSPR) based biosensor for simple and rapid detection of AFP. This biosensor consists of a UV-Vis spectrometer, a cuvette cell, and a biosensor chip nanopatterned with gold nanoparticles (AuNPs). In our LSPR biosensor, binding of AFP to the surface of the sensor chip led to an increasing magnitude of the LSPR signals, which was measured by an ultraviolet-visible (UV-Vis) spectrometer. Our LSPR biosensor showed sufficient detectability of AFP at concentrations of 1 ng/mL to 1 μg/mL. Moreover, the overall procedure for detection of AFP was completed within 20 min. This biosensor could also be utilized for a point of care test (POCT) by employing a portable UV-Vis spectrometer. Owing to the simplicity and rapidity of the detection process, our LSPR biosensor is expected to replace traditional diagnostic methods for the early detection of diseases.

  18. Rapid HPLC method for the simultaneous monitoring of duloxetine, venlaflaxine, fluoxetine and paroxetine in biofluids.

    Science.gov (United States)

    Samanidou, Victoria F; Kourti, Paraskevi V

    2009-08-01

    A simple and rapid HPLC method is developed for the determination of two serotonin-norepinephrine-reuptake inhibitors (duloxetine and venlaflaxine) and two selective serotonin-reuptake inhibitors (fluoxetine and paroxetine) in human biofluids. Separation was performed on an Inertsil ODS-3 column (250 x 4.0 mm, 5 µm) with acetonitrile-ammonium acetate (0.05 M, 41:59 v/v) at 235 nm, within 7 min. SPE on Oasis(®) HLB cartridges was applied for the isolation of analytes from biofluids. The developed methodology was validated in terms of sensitivity, linearity, accuracy, precision, stability and selectivity. Relative standard deviation was less than 10.4%. Limit of detection was 0.2-0.6 ng/µl in blood plasma and 0.1-0.8 ng/µl in urine. The method was successfully applied to biofluids from a patient under duloxetine treatment.

  19. A rapid and scalable method for selecting recombinant mouse monoclonal antibodies

    Directory of Open Access Journals (Sweden)

    Wright Gavin J

    2010-06-01

    Full Text Available Abstract Background Monoclonal antibodies with high affinity and selectivity that work on wholemount fixed tissues are valuable reagents to the cell and developmental biologist, and yet isolating them remains a long and unpredictable process. Here we report a rapid and scalable method to select and express recombinant mouse monoclonal antibodies that are essentially equivalent to those secreted by parental IgG-isotype hybridomas. Results Increased throughput was achieved by immunizing mice with pools of antigens and cloning - from small numbers of hybridoma cells - the functionally rearranged light and heavy chains into a single expression plasmid. By immunizing with the ectodomains of zebrafish cell surface receptor proteins expressed in mammalian cells and screening for formalin-resistant epitopes, we selected antibodies that gave expected staining patterns on wholemount fixed zebrafish embryos. Conclusions This method can be used to quickly select several high quality monoclonal antibodies from a single immunized mouse and facilitates their distribution using plasmids.

  20. A method for rapidly screening functionality of actin mutants and tagged actins

    Directory of Open Access Journals (Sweden)

    Rommelaere Heidi

    2004-01-01

    Full Text Available Recombinant production and biochemical analysis of actin mutants has been hampered by the fact that actin has an absolute requirement for the eukaryotic chaperone CCT to reach its native state. We therefore have developed a method to rapidly screen the folding capacity and functionality of actin variants, by combining in vitro expression of labelled actin with analysis on native gels, band shift assays or copolymerization tests. Additionally, we monitor, using immuno-fluorescence, incorporation of actin variants in cytoskeletal structures in transfected cells. We illustrate the method by two examples. In one we show that tagged versions of actin do not always behave native-like and in the other we study some of the molecular defects of three &bgr;-actin mutants that have been associated with diseases.

  1. A rapid and efficient DNA extraction method suitable for marine macroalgae.

    Science.gov (United States)

    Ramakrishnan, Gautham Subramaniam; Fathima, Anwar Aliya; Ramya, Mohandass

    2017-12-01

    Macroalgae are a diverse group of organisms. Marine macroalgae, in particular, have numerous medicinal and industrial applications. Molecular studies of macroalgae require suitable concentrations of DNA free of contaminants. At present, numerous protocols exist for DNA extraction from macroalgae. However, they are either time consuming, expensive or work only with few species. The method described in this study is rapid and efficient and applicable to different types of marine macroalgae. This method yields an average of 3.85 µg of DNA per 50 mg of algal tissue, with an average purity of 1.88. The isolated DNA was suitable for PCR amplification of universal plastid region of macroalgae.

  2. Colorimetric Sensor Arrays for the Detection and Identification of Chemical Weapons and Explosives.

    Science.gov (United States)

    Kangas, Michael J; Burks, Raychelle M; Atwater, Jordyn; Lukowicz, Rachel M; Williams, Pat; Holmes, Andrea E

    2017-03-04

    There is a significant demand for devices that can rapidly detect chemical-biological-explosive (CBE) threats on-site and allow for immediate responders to mitigate spread, risk, and loss. The key to an effective reconnaissance mission is a unified detection technology that analyzes potential threats in real time. In addition to reviewing the current state of the art in the field, this review illustrates the practicality of colorimetric arrays composed of sensors that change colors in the presence of analytes. This review also describes an outlook toward future technologies, and describes how they could possibly be used in areas such as war zones to detect and identify hazardous substances.

  3. Meselect – A rapid and effective method for the separation of the main leaf tissue types

    Directory of Open Access Journals (Sweden)

    Julia Svozil

    2016-11-01

    Full Text Available Individual tissues of complex eukaryotic organisms have specific gene expression programs that control their functions. Therefore, tissue-specific molecular information is required to increase our understanding of tissue-specific processes. Established methods in plants to obtain specific tissues or cell types from their organ or tissue context typically require the enzymatic degradation of cell walls followed by fluorescence-activated cell sorting (FACS using plants engineered for localized expression of green fluorescent protein (GFP. This has facilitated the acquisition of valuable data, mainly on root cell type-specific transcript and protein expression. However, FACS of different leaf cell types is difficult because of chlorophyll autofluorescence that interferes with the sorting process. Furthermore, the cell wall composition is different in each cell type. This results in long incubation times for refractory cell types, and cell sorting itself can take several hours. To overcome these limitations, we developed Meselect (mechanical separation of leaf compound tissues, a rapid and effective method for the separation of leaf epidermal, vascular and mesophyll tissues. Meselect is a novel combination of mechanical separation and rapid protoplasting, which benefits from the unique cell wall composition of the different tissue types. Meselect has several advantages over cell sorting: it does not require expensive equipment such as a cell sorter and does not depend on specific fluorescent reporter lines, the use of blenders as well as the inherent mixing of different cell types and of intact and damaged cells can be avoided, and the time between wounding of the leaf and freezing of the sample is short. The efficacy and specificity of the method to enrich the different leaf tissue types has been confirmed using Arabidopsis leaves, but it has also been successfully used for leaves of other plants such as tomato or cassava. The method is therefore

  4. Colorimetric Assay Of Naproxen Tablets by Derivatization Using 4 ...

    African Journals Online (AJOL)

    A colorimetric assay of naproxen tablets based on chemical derivatization with the .... reported to couple with some phenol ethers. (anisole .... Properties, Applications 2nd ... Binding in: Physical Pharmacy: Physical. Chemical. Principles in the.

  5. Photonic crystal structures with tunable structure color as colorimetric sensors

    National Research Council Canada - National Science Library

    Wang, Hui; Zhang, Ke-Qin

    2013-01-01

    Colorimetric sensing, which transduces environmental changes into visible color changes, provides a simple yet powerful detection mechanism that is well-suited to the development of low-cost and low-power sensors...

  6. Development of rapid methods for relaxation time mapping and motion estimation using magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gilani, Syed Irtiza Ali

    2008-09-15

    Recent technological developments in the field of magnetic resonance imaging have resulted in advanced techniques that can reduce the total time to acquire images. For applications such as relaxation time mapping, which enables improved visualisation of in vivo structures, rapid imaging techniques are highly desirable. TAPIR is a Look- Locker-based sequence for high-resolution, multislice T{sub 1} relaxation time mapping. Despite the high accuracy and precision of TAPIR, an improvement in the k-space sampling trajectory is desired to acquire data in clinically acceptable times. In this thesis, a new trajectory, termed line-sharing, is introduced for TAPIR that can potentially reduce the acquisition time by 40 %. Additionally, the line-sharing method was compared with the GRAPPA parallel imaging method. These methods were employed to reconstruct time-point images from the data acquired on a 4T high-field MR research scanner. Multislice, multipoint in vivo results obtained using these methods are presented. Despite improvement in acquisition speed, through line-sharing, for example, motion remains a problem and artefact-free data cannot always be obtained. Therefore, in this thesis, a rapid technique is introduced to estimate in-plane motion. The presented technique is based on calculating the in-plane motion parameters, i.e., translation and rotation, by registering the low-resolution MR images. The rotation estimation method is based on the pseudo-polar FFT, where the Fourier domain is composed of frequencies that reside in an oversampled set of non-angularly, equispaced points. The essence of the method is that unlike other Fourier-based registration schemes, the employed approach does not require any interpolation to calculate the pseudo-polar FFT grid coordinates. Translation parameters are estimated by the phase correlation method. However, instead of two-dimensional analysis of the phase correlation matrix, a low complexity subspace identification of the phase

  7. Autoclave method for rapid preparation of bacterial PCR-template DNA.

    Science.gov (United States)

    Simmon, Keith E; Steadman, Dewey D; Durkin, Sarah; Baldwin, Amy; Jeffrey, Wade H; Sheridan, Peter; Horton, Rene; Shields, Malcolm S

    2004-02-01

    An autoclave method for preparing bacterial DNA for PCR template is presented, it eliminates the use of detergents, organic solvents, and mechanical cellular disruption approaches, thereby significantly reducing processing time and costs while increasing reproducibility. Bacteria are lysed by rapid heating and depressurization in an autoclave. The lysate, cleared by microcentrifugation, was either used directly in the PCR reaction, or concentrated by ultrafiltration. This approach was compared with seven established methods of DNA template preparation from four bacterial sources which included boiling Triton X-100 and SDS, bead beating, lysozyme/proteinase K, and CTAB lysis method components. Bacteria examined were Enterococcus and Escherichia coli, a natural marine bacterial community and an Antarctic cyanobacterial-mat. DNAs were tested for their suitability as PCR templates by repetitive element random amplified polymorphic DNA (RAPD) and denaturing gradient gel electrophoresis (DGGE) analysis. The autoclave method produced PCR amplifiable template comparable or superior to the other methods, with greater reproducibility, much shorter processing time, and at a significantly lower cost.

  8. A tree-based method for the rapid screening of chemical fingerprints

    Directory of Open Access Journals (Sweden)

    Pedersen Christian NS

    2010-01-01

    Full Text Available Abstract Background The fingerprint of a molecule is a bitstring based on its structure, constructed such that structurally similar molecules will have similar fingerprints. Molecular fingerprints can be used in an initial phase of drug development for identifying novel drug candidates by screening large databases for molecules with fingerprints similar to a query fingerprint. Results In this paper, we present a method which efficiently finds all fingerprints in a database with Tanimoto coefficient to the query fingerprint above a user defined threshold. The method is based on two novel data structures for rapid screening of large databases: the kD grid and the Multibit tree. The kD grid is based on splitting the fingerprints into k shorter bitstrings and utilising these to compute bounds on the similarity of the complete bitstrings. The Multibit tree uses hierarchical clustering and similarity within each cluster to compute similar bounds. We have implemented our method and tested it on a large real-world data set. Our experiments show that our method yields approximately a three-fold speed-up over previous methods. Conclusions Using the novel kD grid and Multibit tree significantly reduce the time needed for searching databases of fingerprints. This will allow researchers to (1 perform more searches than previously possible and (2 to easily search large databases.

  9. Development of a micropulverized extraction method for rapid toxicological analysis of methamphetamine in hair.

    Science.gov (United States)

    Miyaguchi, Hajime; Kakuta, Masaya; Iwata, Yuko T; Matsuda, Hideaki; Tazawa, Hidekatsu; Kimura, Hiroko; Inoue, Hiroyuki

    2007-09-07

    We developed a rapid sample preparation method for the toxicological analysis of methamphetamine and amphetamine (the major metabolite of methamphetamine) in human hair by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), to facilitate fast screening and quantitation. Two milligrams of hair were mechanically micropulverized for 5 min in a 2-ml plastic tube together with 100 microl of an aqueous solvent containing 10% acetonitrile, 100 mM trifluoroacetic acid and the corresponding deuterium analogues as internal standards. The pulverizing highly disintegrated the hair components, simultaneously allowing the extraction of any drugs present in the hair. After filtering the suspension with a membrane-filter unit, the clear filtrate was directly analyzed by HPLC-MS/MS. No evaporation processes were required for sample preparation. Method optimization and validation study were carried out using real-case specimens and fortified samples in which the drugs had been artificially absorbed, respectively. Concentration ranges for quantitation were 0.040-125 and 0.040-25 ng/mg for methamphetamine and amphetamine, respectively. Real-case specimens were analyzed by the method presented here and by conventional ones to verify the applicability of our method to real-world analysis. Our method took less than 30 min for a set of chromatograms to be obtained from a washed hair sample.

  10. Development of a Tunable LED-Based Colorimetric Source

    OpenAIRE

    Brown, Steven W.; Santana, Carlos; Eppeldauer, George P.

    2002-01-01

    A novel, spectrally tunable light-source utilizing light emitting diodes (LEDs) for radiometric, photometric, and colorimetric applications is described. The tunable source can simulate standard sources and can be used as a transfer source to propagate photometric and colorimetric scales from calibrated reference instruments to test artifacts with minimal increase in uncertainty. In this prototype source, 40 LEDs with 10 different spectral distributions were mounted onto an integrating sphere...

  11. Functionalized magnetic microparticle-based colorimetric platform for influenza A virus detection

    Science.gov (United States)

    Chen, Chaohui; Zou, Zhong; Chen, Lu; Ji, Xinghu; He, Zhike

    2016-10-01

    A colorimetric platform for influenza A virus detection was developed by using the high efficiency of enzymatic catalysis and the reduction of gold ions with hydrogen peroxide. Aptamer-functionalized magnetic microparticles were synthesized to capture the influenza A virus. This was followed by the binding of ConA-GOx-AuNPs to the H3N2 virus through the ConA-glycan interaction. The sandwich complex was subsequently dispersed in glucose solution to trigger an enzymatic reaction to produce hydrogen peroxide, which controlled the growth of gold nanoparticles and produced colored solutions. The determination of H3N2 concentration was realized by comparing the two differently colored gold nanoparticles. This method could detect the target virus as low as 11.16 μg ml-1. Furthermore, it opens new opportunities for sensitive and colorimetric detection of viruses and proteins.

  12. Bio-inspired colorimetric film based on hygroscopic coloration of longhorn beetles (Tmesisternus isabellae).

    Science.gov (United States)

    Seo, Han-Bok; Lee, Seung-Yop

    2017-03-21

    Structure-dependent colour is caused by the interaction of light with photonic crystal structures rather than pigments. The elytra of longhorn beetles Tmesisternus isabellae appear to be iridescent green in a dry state and turn to red when exposed to humidity. Based on the hygroscopic colouration of the longhorn beetle, we have developed centimeter-scale colorimetric opal films using a novel self-assembly method. The micro-channel assisted assembly technique adopts both natural evaporation and rotational forced drying, enhancing the surface binding of silica particles and the packing density by reducing the lattice constant and structural defects. The fabricated large-scale photonic film changes its structural colour from green to red when exposed to water vapour, similarly to the colorimetric feature of the longhorn beetle. The humidity-dependent colour change of the opal film is shown to be reversible and durable over five-hundred cycles of wetting and drying.

  13. Bio-inspired colorimetric film based on hygroscopic coloration of longhorn beetles (Tmesisternus isabellae)

    Science.gov (United States)

    Seo, Han-Bok; Lee, Seung-Yop

    2017-03-01

    Structure-dependent colour is caused by the interaction of light with photonic crystal structures rather than pigments. The elytra of longhorn beetles Tmesisternus isabellae appear to be iridescent green in a dry state and turn to red when exposed to humidity. Based on the hygroscopic colouration of the longhorn beetle, we have developed centimeter-scale colorimetric opal films using a novel self-assembly method. The micro-channel assisted assembly technique adopts both natural evaporation and rotational forced drying, enhancing the surface binding of silica particles and the packing density by reducing the lattice constant and structural defects. The fabricated large-scale photonic film changes its structural colour from green to red when exposed to water vapour, similarly to the colorimetric feature of the longhorn beetle. The humidity-dependent colour change of the opal film is shown to be reversible and durable over five-hundred cycles of wetting and drying.

  14. Evaluation of a PCR/DNA Probe Colorimetric Membrane Assay for Identification of Campylobacter spp. in Human Stool Specimens

    OpenAIRE

    Collins, Evelyn; Glennon, Maura; Hanley, Shirley; Murray, Anne-Marie; Cormican, Martin; Smith, Terry; Maher, Majella

    2001-01-01

    DNA was extracted from 50 human stool specimens using the QIAamp DNA stool minikit. PCR amplification was followed by post-PCR hybridization to DNA probes specific for the Campylobacter genus, Campylobacter jejuni, and Campylobacter coli in a colorimetric membrane assay. Thirty-two of 38 culture-positive specimens were PCR/DNA probe positive for C. jejuni. The assay is rapid and simple and can be applied to stool specimens for the detection of Campylobacter.

  15. NATO Advanced Research Workshop, 19-22 May 1997: Rapid Method for Monitoring the Environment for Biological Hazards.

    Science.gov (United States)

    1997-05-22

    The NATO Advanced Research Workshop met for the purpose of bringing to light rapid methods for monitoring the environment for biological hazards such as biological warfare agents, naturally occurring diseases, detection and identification of different biological threats in the environment , dormancy in non-sporulating bacteria and bioluminescence techniques with respect to the rapid detection of microbes in air, water and food.

  16. Plasmon-Based Colorimetric Nanosensors for Ultrasensitive Molecular Diagnostics.

    Science.gov (United States)

    Tang, Longhua; Li, Jinghong

    2017-07-28

    Colorimetric detection of target analytes with high specificity and sensitivity is of fundamental importance to clinical and personalized point-of-care diagnostics. Because of their extraordinary optical properties, plasmonic nanomaterials have been introduced into colorimetric sensing systems, which provide significantly improved sensitivity in various biosensing applications. Here we review the recent progress on these plasmonic nanoparticles-based colorimetric nanosensors for ultrasensitive molecular diagnostics. According to their different colorimetric signal generation mechanisms, these plasmonic nanosensors are classified into two categories: (1) interparticle distance-dependent colorimetric assay based on target-induced forming cross-linking assembly/aggregate of plasmonic nanoparticles; and (2) size/morphology-dependent colorimetric assay by target-controlled growth/etching of the plasmonic nanoparticles. The sensing fundamentals and cutting-edge applications will be provided for each of them, particularly focusing on signal generation and/or amplification mechanisms that realize ultrasensitive molecular detection. Finally, we also discuss the challenge and give our future perspective in this emerging field.

  17. Rapid Assessment of Health Services in Punjab using a Mixed Method Approach

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar

    2015-06-01

    Full Text Available Introduction: The out-of-pocket expenditure is quite high in Punjab. Hence, a rapid review of health facilities was undertaken to suggest remedial measures. Methods: Mixed method research approach was used to identify strengths and weaknesses of the health services in Punjab. All health institutions were included in the assessment from the three purposively sampled districts – one from each of the three regions of Punjab. Tools were developed to collect data from record review, observations, and in-depth interviews. Six building blocks framework proposed by the World Health Organization was used for data collection and analyses. Results: In general physical infrastructure, especially the buildings were found to be reasonably constructed at most of the healthcare facilities. However, the maintenance was not regular. The vacancies for general doctors, specialist doctors, nurses, and paramedics were 26%, 38%, 31% and 12% respectively. Supply of drugs was irregular and inadequate. A large proportion (45% of ‘user charges’ were spent on purchase of drugs and other consumables. Most registers were found to be updated, and reports were transmitted to higher levels usually on time. However, institutionalized system of monitoring and supervision was lacking. Govt. hospitals were providing in-patient care to about 35.5% of those who were estimated to need hospitalization. State had allocated about Rs. 1200 crores to health (0.46% of GDP, thus, spending only Rs. 433 per capita per year. Conclusions: Despite constraints, the government health service is catering to the needs of a large section of the population. Rapid health system assessment at periodic intervals using a mixed method approach can supplement routine monitoring of the health system.

  18. A New Colorimetric Assay of Tabletop Sweeteners Using a Modified Biuret Reagent: An Analytical Chemistry Experiment for the Undergraduate Curriculum

    Science.gov (United States)

    Fenk, Christopher J.; Kaufman, Nathan; Gerbig, Donald G., Jr.

    2007-01-01

    A new, fast and effective colorimetric analysis of the artificial sweetener aspartame is presented for application in undergraduate laboratory courses. This new method incorporates the use of a modified biuret reagent for selective detection and analysis of aspartame in aqueous solutions. The modified reagent is less caustic than the traditional…

  19. A rapid method of detecting autoantibody against FcεRIα for chronic spontaneous urticaria.

    Directory of Open Access Journals (Sweden)

    Mey-Fann Lee

    Full Text Available BACKGROUND: Chronic spontaneous urticaria (CU is a common skin disorder, with an estimated prevalence of 0.5-1.8% in most populations. Around 30-50% of CU patients have an autoimmune etiology, with autoantibodies (autoAbs against IgE, FcεRIα, and FcεRII/CD23. Although the in vivo autologous serum skin test (ASST and in vitro histamine release/activation assay are the most frequently used screening methods, these two have many limitations and do not directly measure susceptible autoAbs. This study aimed to establish an in vitro rapid screening test using recombinant autoantigen FcεRIα(rFcεRIα to improve the diagnosis of autoimmune urticaria. METHODS: Forty patients with CU and 20 healthy individuals were enrolled. After PCR-based cloning and the production of extracellular fragments of the FcεRIα protein using the E. coli expression system, serum autoAb to rFcεRIα was evaluated using in-house ELISA and rapid immunodot test. RESULTS: In ELISA-based detection, 14 out of 20 CU-ASST(+ patients exhibited anti- FcεRIα responses, whereas five of the 20 CU-ASST(- and two of the 20 non-CU patients showed autoantibody background in the assay. For the immunodot test, 55% (11/20 of the CU-ASST(+ sera exhibited anti-FcεRIα reactivity. There was no false positive among the CU-ASST(- and non-CU groups. Using clinical urticaria plus ASST(+ as the gold standard, in-house ELISA had 70% sensitivity, 82.5% specificity, and positive likelihood ratio of 4, while immunodot had 55% sensitivity, 100% specificity, and positive likelihood ratio >55. CONCLUSIONS: This study has developed a rapid immunodot method with high specificity for detecting autoAb to FcεRIαin patients with CU. Preliminary data indicates that this immunodot technique has the potential to be a routine diagnostic assay for autoimmune CU.

  20. Rapid Hydrothermal Synthesis of Zinc Oxide Nanowires by Annealing Methods on Seed Layers

    Directory of Open Access Journals (Sweden)

    Jang Bo Shim

    2011-01-01

    Full Text Available Well-aligned zinc oxide (ZnO nanowire arrays were successfully synthesized on a glass substrate using the rapid microwave heating process. The ZnO seed layers were produced by spinning the precursor solutions onto the substrate. Among coatings, the ZnO seed layers were annealed at 100°C for 5 minutes to ensure particle adhesion to the glass surface in air, nitrogen, and vacuum atmospheres. The annealing treatment of the ZnO seed layer was most important for achieving the high quality of ZnO nanowire arrays as ZnO seed nanoparticles of larger than 30 nm in diameter evolve into ZnO nanowire arrays. Transmission electron microscopy analysis revealed a single-crystalline lattice of the ZnO nanowires. Because of their low power (140 W, low operating temperatures (90°C, easy fabrication (variable microwave sintering system, and low cost (90% cost reduction compared with gas condensation methods, high quality ZnO nanowires created with the rapid microwave heating process show great promise for use in flexible solar cells and flexible display devices.

  1. A Rapid and Efficient Method for Evaluation of Suspect Testimony: Palynological Scanning.

    Science.gov (United States)

    Wiltshire, Patricia E J; Hawksworth, David L; Edwards, Kevin J

    2015-11-01

    A rapid method for evaluating suspect testimony is valuable at any stage in an inquiry and can result in a change of direction in an investigation. Rape cases, in particular, can present problems where a defendant renders DNA analysis redundant by claiming that the claimant consented to have sexual relations. Forensic palynology is valuable in confirming or eliminating locations as being crime scenes, thus checking the testimony of both parties. In contrast to some forensic disciplines, forensic palynology can provide critical information without time-consuming full analysis. Two cases are described where the palynological assemblages from comparator samples of pertinent places were compared with those obtained from clothing of claimants and defendants. The results of rapid microscopical scanning of relevant preparations led to early confessions, thus obviating the need for costly analyses and protracted court proceedings. A third case demonstrates the unbiased nature of this technique where a man, although innocent of any offense, lied about having visited the crime scene for fear of prosecution. This highlights the need for sensitive policing in claims of rape. © 2015 American Academy of Forensic Sciences.

  2. Rapid and Sensitive Lateral Flow Immunoassay Method for Procalcitonin (PCT Based on Time-Resolved Immunochromatography

    Directory of Open Access Journals (Sweden)

    Xiang-Yang Shao

    2017-02-01

    Full Text Available Procalcitonin (PCT is a current, frequently-used marker for severe bacterial infection. The aim of this study was to develop a cost-effective detection kit for rapid quantitative and on-site detection of PCT. To develop the new PCT quantitative detecting kit, a double-antibody sandwich immunofluorescent assay was employed based on time-resolved immunofluorescent assay (TRFIA combined with lateral flow immunoassay (LFIA. The performance of the new developed kit was evaluated in the aspects of linearity, precision, accuracy, and specificity. Two-hundred thirty-four serum samples were enrolled to carry out the comparison test. The new PCT quantitative detecting kit exhibited a higher sensitivity (0.08 ng/mL. The inter-assay coefficient of variation (CV and the intra-assay CV were 5.4%–7.7% and 5.7%–13.4%, respectively. The recovery rates ranged from 93% to 105%. Furthermore, a high correlation (n = 234, r = 0.977, p < 0.0001 and consistency (Kappa = 0.875 were obtained when compared with the PCT kit from Roche Elecsys BRAHMS. Thus, the new quantitative method for detecting PCT has been successfully established. The results indicated that the newly-developed system based on TRFIA combined with LFIA was suitable for rapid and on-site detection for PCT, which might be a useful platform for other biomarkers in point-of-care tests.

  3. Bacterial Cytological Profiling (BCP as a Rapid and Accurate Antimicrobial Susceptibility Testing Method for Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    D.T. Quach

    2016-02-01

    Full Text Available Successful treatment of bacterial infections requires the timely administration of appropriate antimicrobial therapy. The failure to initiate the correct therapy in a timely fashion results in poor clinical outcomes, longer hospital stays, and higher medical costs. Current approaches to antibiotic susceptibility testing of cultured pathogens have key limitations ranging from long run times to dependence on prior knowledge of genetic mechanisms of resistance. We have developed a rapid antimicrobial susceptibility assay for Staphylococcus aureus based on bacterial cytological profiling (BCP, which uses quantitative fluorescence microscopy to measure antibiotic induced changes in cellular architecture. BCP discriminated between methicillin-susceptible (MSSA and -resistant (MRSA clinical isolates of S. aureus (n = 71 within 1–2 h with 100% accuracy. Similarly, BCP correctly distinguished daptomycin susceptible (DS from daptomycin non-susceptible (DNS S. aureus strains (n = 20 within 30 min. Among MRSA isolates, BCP further identified two classes of strains that differ in their susceptibility to specific combinations of beta-lactam antibiotics. BCP provides a rapid and flexible alternative to gene-based susceptibility testing methods for S. aureus, and should be readily adaptable to different antibiotics and bacterial species as new mechanisms of resistance or multidrug-resistant pathogens evolve and appear in mainstream clinical practice.

  4. OSO paradigm--A rapid behavioral screening method for acute psychosocial stress reactivity in mice.

    Science.gov (United States)

    Brzózka, M M; Unterbarnscheidt, T; Schwab, M H; Rossner, M J

    2016-02-09

    Chronic psychosocial stress is an important environmental risk factor for the development of psychiatric diseases. However, studying the impact of chronic psychosocial stress in mice is time consuming and thus not optimally suited to 'screen' increasing numbers of genetically manipulated mouse models for psychiatric endophenotypes. Moreover, many studies focus on restraint stress, a strong physical stressor with limited relevance for psychiatric disorders. Here, we describe a simple and a rapid method based on the resident-intruder paradigm to examine acute effects of mild psychosocial stress in mice. The OSO paradigm (open field--social defeat--open field) compares behavioral consequences on locomotor activity, anxiety and curiosity before and after exposure to acute social defeat stress. We first evaluated OSO in male C57Bl/6 wildtype mice where a single episode of social defeat reduced locomotor activity, increased anxiety and diminished exploratory behavior. Subsequently, we applied the OSO paradigm to mouse models of two schizophrenia (SZ) risk genes. Transgenic mice with neuronal overexpression of Neuregulin-1 (Nrg1) type III showed increased risk-taking behavior after acute stress exposure suggesting that NRG1 dysfunction is associated with altered affective behavior. In contrast, Tcf4 transgenic mice displayed a normal stress response which is in line with the postulated predominant contribution of TCF4 to cognitive deficits of SZ. In conclusion, the OSO paradigm allows for rapid screening of selected psychosocial stress-induced behavioral endophenotypes in mouse models of psychiatric diseases. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. Performance of a Micro-UAV lifting system built with the usage of rapid prototyping methods

    Science.gov (United States)

    Dalewski, R. T.; Gumowski, K.; Barczak, T.; Godek, J.

    2014-08-01

    This article presents results of the aerodynamic testing of a micro unmanned aerial vehicle rotor efficiency. The rotors were prepared as a set of two rotors in a counter-rotating ducted drive. Prototypes of the drives were made using two rapid prototyping techniques - FDM - fused deposition modelling method and SLS - selective laser sintering. Rotors were made then treated by introducing additional finishing cyanoacrylate coating and abrasive processing. Main differences between those models were observed in fan shape, porosity, surface roughness and mechanical properties - stiffness. An influence of these factors was observed on an aerodynamic efficiency. For the obtained prototypes both simulations and experimental testing were conducted with thrust, power, torque measurements, as well as the measurement of velocity and pressure distribution at the outlet of the duct. The results show the possibility of using rapid prototyping techniques to produce prototypes of drives operating in the low and medium Reynolds numbers (6000-60000), and the aerodynamic shape relevant factors affecting the preparation and performance of such drives. In addition, simulation studies were performed using the Fluent environment where experimental results were confronted with the results of simulation studies.

  6. Use of a modified cluster sampling method to perform rapid needs assessment after Hurricane Andrew.

    Science.gov (United States)

    Hlady, W G; Quenemoen, L E; Armenia-Cope, R R; Hurt, K J; Malilay, J; Noji, E K; Wurm, G

    1994-04-01

    To rapidly obtain population-based estimates of needs in the early aftermath of Hurricane Andrew in South Florida. We used a modified cluster-sampling method (the Expanded Programme on Immunization [EPI] method) for three surveys. We selected a systematic sample of 30 quarter-mile square clusters for each survey and, beginning from a random start, interviewed members of seven consecutive occupied households in each cluster. Two surveys were of the most affected area (1990 population, 32,672) at three and ten days after the hurricane struck; one survey was of a less affected area (1990 population, 15,576) seven days after the hurricane struck. Results were available within 24 hours of beginning each survey. Initial findings emphasized the need for restoring utilities and sanitation and helped to focus medical relief on primary care and preventive services. The second survey of the most affected area showed improvement in the availability of food, water, electricity, and sanitation (P < or = .05). There was no evidence of disease outbreaks. For the first time, the EPI method provided population-based information to guide and evaluate relief operations after a sudden-impact natural disaster. An improvement over previous approaches, the EPI method warrants further evaluation as a needs assessment tool in acute disasters.

  7. ATP bioluminescence method: tool for rapid screening of organic and microbial contaminants on deteriorated mural paintings.

    Science.gov (United States)

    Unković, Nikola; Ljaljević Grbić, Milica; Stupar, Miloš; Vukojević, Jelena; Subakov-Simić, Gordana; Jelikić, Aleksa; Stanojević, Dragan

    2015-11-24

    The extent of the microbial contamination of the seventeenth-century wall paintings in the nave of the old Church of the Holy Ascension (Veliki Krčimir, Serbia) was evaluated via newly implemented ATP bioluminescence method, and traditional cultivation-based method, utilising commercially available dip slides. To assess the validity of ATP, as a biomarker for rapid detection of mural surface contamination, obtained zones of cleanliness values, in range from 1.0 to 5.3, were compared to documented total microbial counts, ranging between seven and 247 CFU/cm 2 . Small coefficients of determination, 0.0106-0.0385, suggest poor correlation between microbial counts and surface ATP levels; however, zones of cleanliness values are of great help in determining the high points of contamination, aka 'hotspots', which should be given special attention during sampling and investigation using other methods. In addition, various aspects of the possible implementation of the ATP bioluminescence method in an integrated system of wall painting conservation are discussed.

  8. A Rapid Dialysis Method for Analysis of Artificial Sweeteners in Foods (2nd Report).

    Science.gov (United States)

    Tahara, Shoichi; Yamamoto, Sumiyo; Yamajima, Yukiko; Miyakawa, Hiroyuki; Uematsu, Yoko; Monma, Kimio

    2017-01-01

    Following the previous report, a rapid dialysis method was developed for the extraction and purification of four artificial sweeteners, namely, sodium saccharide (Sa), acesulfame potassium (AK), aspartame (APM), and dulcin (Du), which are present in various foods. The method was evaluated by the addition of 0.02 g/kg of these sweeteners to a cookie sample, in the same manner as in the previous report. Revisions from the previous method were: reduction of the total dialysis volume from 200 to 100 mL, change of tube length from 55 to 50 cm, change of dialysate from 0.01 mol/L hydrochloric aqueous solution containing 10% sodium chloride to 30% methanol solution, and change of dialysis conditions from ambient temperature with occasional shaking to 50℃ with shaking at 160 rpm. As a result of these revisions, the recovery reached 99.3-103.8% with one hour dialysis. The obtained recovery yields were comparable to the recovery yields in the previous method with four hour dialysis.

  9. ReagentTF: a rapid and versatile optical clearing method for biological imaging(Conference Presentation)

    Science.gov (United States)

    Yu, Tingting; Zhu, Jingtan; Li, Yusha; Qi, Yisong; Xu, Jianyi; Gong, Hui; Luo, Qingming; Zhu, Dan

    2017-02-01

    The emergence of various optical clearing methods provides a great potential for imaging deep inside tissues by combining with multiple-labelling and microscopic imaging techniques. They were generally developed for specific imaging demand thus presented some non-negligible limitations such as long incubation time, tissue deformation, fluorescence quenching, incompatibility with immunostaining or lipophilic tracers. In this study, we developed a rapid and versatile clearing method, termed ReagentTF, for deep imaging of various fluorescent samples. This method can not only efficiently clear embryos, neonatal whole-brains and adult thick brain sections by simple immersion in aqueous mixtures with minimal volume change, but also can preserve fluorescence of various fluorescent proteins and simultaneously be compatible with immunostaining and lipophilic neuronal dyes. We demonstrate the effectiveness of this method in reconstructing the cell distributions of mouse hippocampus, visualizing the neural projection from CA1 (Cornu Ammonis 1) to HDB (nucleus of the horizontal limb of the diagonal band), and observing the growth of forelimb plexus in whole-mount embryos. These results suggest that ReagentTF is useful for large-volume imaging and will be an option for the deep imaging of biological tissues.

  10. Computationally rapid method of estimating signal-to-noise ratio for phased array image reconstructions.

    Science.gov (United States)

    Wiens, Curtis N; Kisch, Shawn J; Willig-Onwuachi, Jacob D; McKenzie, Charles A

    2011-10-01

    Measuring signal-to-noise ratio (SNR) for parallel MRI reconstructions is difficult due to spatially dependent noise amplification. Existing approaches for measuring parallel MRI SNR are limited because they are not applicable to all reconstructions, require significant computation time, or rely on repeated image acquisitions. A new SNR estimation approach is proposed, a hybrid of the repeated image acquisitions method detailed in the National Electrical Manufacturers Association (NEMA) standard and the Monte Carlo based pseudo-multiple replica method, in which the difference between images reconstructed from the unaltered acquired data and that same data reconstructed after the addition of calibrated pseudo-noise is used to estimate the noise in the parallel MRI image reconstruction. This new noise estimation method can be used to rapidly compute the pixel-wise SNR of the image generated from any parallel MRI reconstruction of a single acquisition. SNR maps calculated with the new method are validated against existing SNR calculation techniques. Copyright © 2011 Wiley-Liss, Inc.

  11. A rapid and sensitive method for the detection of aromatic amines in cosmetics.

    Science.gov (United States)

    Hailong, Xiao; Fen, Qian; Ying, Xu; Jianhong, Pan; Haiyun, Tu; Hongqing, Wang; Saijun, Lin; Jichun, Han

    2014-02-01

    Aromatic amines (AAs) are common chemical pollutants and banned ingredients in cosmetics. In this study, a rapid, simple and stable method for the detection of nine AAs in cosmetics was established based on the optimization of cation exchange solid-phase extraction and liquid chromatography tandem mass spectrometry. The method displayed good linearity within a range of 2-1,000 µg/kg, with limits of quantitation at the level of µg/kg for cosmetic samples. The recoveries obtained for all analyzed amines ranged between 83.6 and 97.8%, and the repeatability (r) and reproducibility (R) values indicated that all nine AAs showed good precision (r ≤ 4.5% and R ≤ 7.7%). The method was applied for the detection of 36 cosmetic samples. It was found that the primary pollutants of AAs were 3, 3'-dichlorobenzidine and 4-aminoazobenzene. The total amine concentration in cosmetic samples ranged from 880 to 5,200 µg/kg. The proposed method is applicable for the analysis of most cosmetic samples.

  12. A simple and rapid method to characterize lipid fate in skeletal muscle.

    Science.gov (United States)

    Massart, Julie; Zierath, Juleen R; Chibalin, Alexander V

    2014-06-24

    Elevated fatty acids contribute to the development of type 2 diabetes and affect skeletal muscle insulin sensitivity. Since elevated intramuscular lipids and insulin resistance is strongly correlated, aberrant lipid storage or lipid intermediates may be involved in diabetes pathogenesis. The aim of this study was to develop a method to determine the dynamic metabolic fate of lipids in primary human skeletal muscle cells and in intact mouse skeletal muscle. We report a simple and fast method to characterize lipid profiles in skeletal muscle using thin layer chromatography. The described method was specifically developed to assess lipid utilization in cultured and intact skeletal muscle. We determined the effect of a pan-diacylglycerol kinase (DGK) class I inhibitor (R59949) on lipid metabolism to validate the method. In human skeletal muscle cells, DGK inhibition impaired diacylglycerol (DAG) conversion to phosphatidic acid and increased triglyceride synthesis. In intact glycolytic mouse skeletal muscle, DGK inhibition triggered the accumulation of DAG species. Conversely, the DGK inhibitor did not affect DAG content in oxidative muscle. This simple assay detects rapid changes in the lipid species composition of skeletal muscle with high sensitivity and specificity. Determination of lipid metabolism in skeletal muscle may further elucidate the mechanisms contributing to the pathogenesis of insulin resistance in type 2 diabetes or obesity.

  13. A new rapid method for Clostridium difficile DNA extraction and detection in stool: toward point-of-care diagnostic testing

    National Research Council Canada - National Science Library

    Freifeld, Alison G; Simonsen, Kari A; Booth, Christine S; Zhao, Xing; Whitney, Scott E; Karre, Teresa; Iwen, Peter C; Viljoen, Hendrik J

    2012-01-01

    We describe a new method for the rapid diagnosis of Clostridium difficile infection, with stool sample preparation and DNA extraction by heat and physical disruption in a single-use lysis microreactor (LMR...

  14. A novel method for ATLAS FSI alignment based on rapid, direct phase monitoring

    CERN Document Server

    Gibson, S M; The ATLAS collaboration; Horton, K; Lewis, A; Liang, Z; Livermore, S; Mattravers, C; Nickerson, R B

    2010-01-01

    Frequency Scanning Interferometry is a precise, multiple distance measurement technique, originally developed for ATLAS, which is suited to a variety of applications in the survey and alignment of future accelerators and particle detectors. The ATLAS inner detector is instrumented with an automated FSI alignment system, capable of simultaneously measuring hundreds of interferometers within the operational particle tracker. The alignment system began data taking in 2008 and we present the latest results from the on-detector system during LHC running. A new method has been developed based on rapid, direct monitoring of the interferometer phase, which allows the measurement of short term motions with improved precision, at a fraction of the wavelength of light (typically sensitive to < 50 nm). We outline the theory behind this novel technique and demonstrate precise measurements from ATLAS, which reveal interesting micron-level movements of the inner detector, correlated with thermal cycles and magnetic f...

  15. Apparatus and method for rapid cooling of large area substrates in vacuum

    Science.gov (United States)

    Barth, Kurt L.; Enzenroth, Robert A.; Sampath, Walajabad S.

    2010-09-28

    The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.

  16. A rapid and economic in-house DNA purification method using glass syringe filters.

    Directory of Open Access Journals (Sweden)

    Yun-Cheol Kim

    Full Text Available BACKGROUND: Purity, yield, speed and cost are important considerations in plasmid purification, but it is difficult to achieve all of these at the same time. Currently, there are many protocols and kits for DNA purification, however none maximize all four considerations. METHODOLOGY/PRINCIPAL FINDINGS: We now describe a fast, efficient and economic in-house protocol for plasmid preparation using glass syringe filters. Plasmid yield and quality as determined by enzyme digestion and transfection efficiency were equivalent to the expensive commercial kits. Importantly, the time required for purification was much less than that required using a commercial kit. CONCLUSIONS/SIGNIFICANCE: This method provides DNA yield and quality similar to that obtained with commercial kits, but is more rapid and less costly.

  17. A robust and rapid method of producing soluble, stable, and functional G-protein coupled receptors.

    Directory of Open Access Journals (Sweden)

    Karolina Corin

    Full Text Available Membrane proteins, particularly G-protein coupled receptors (GPCRs, are notoriously difficult to express. Using commercial E. coli cell-free systems with the detergent Brij-35, we could rapidly produce milligram quantities of 13 unique GPCRs. Immunoaffinity purification yielded receptors at >90% purity. Secondary structure analysis using circular dichroism indicated that the purified receptors were properly folded. Microscale thermophoresis, a novel label-free and surface-free detection technique that uses thermal gradients, showed that these receptors bound their ligands. The secondary structure and ligand-binding results from cell-free produced proteins were comparable to those expressed and purified from HEK293 cells. Our study demonstrates that cell-free protein production using commercially available kits and optimal detergents is a robust technology that can be used to produce sufficient GPCRs for biochemical, structural, and functional analyses. This robust and simple method may further stimulate others to study the structure and function of membrane proteins.

  18. Rapid method for surveying CO concentrations in high-rise buildings

    Energy Technology Data Exchange (ETDEWEB)

    Flachsbart, P.G.; Ott, W.R.

    1986-01-01

    A rapid method for employing personal exposure monitors (PEMs) to measure carbon monoxide (CO) concentrations in high-rise buildings is described. The purpose is to determine whether or not a CO problem exists in a building, and, if so, what corrective actions should be taken. The methodology was applied to a 15-story building in Palo Alto, CA, where elevated CO concentrations were discovered on the first 11 floors. The source appeared to be an underground parking garage. A follow-up survey four years later revealed that mitigative measures designed to reduce these concentrations had been successful. The survey methodology is inexpensive and can be applied to a number of buildings in a city.

  19. Evaluation of rapid alternative methods for drug susceptibility testing in clinical isolates of Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Luciano Mengatto

    2006-08-01

    Full Text Available A study was carried out to compare the performance of a commercial method (MGIT and four inexpensive drug susceptibility methods: nitrate reductase assay (NRA, microscopic observation drug susceptibility (MODS assay, MTT test, and broth microdilution method (BMM. A total of 64 clinical isolates of Mycobacterium tuberculosis were studied. The Lowenstein-Jensen proportion method (PM was used as gold standard. MGIT, NRA, MODS, and MTT results were available on an average of less than 10 days, whereas BMM results could be reported in about 20 days. Most of the evaluated tests showed excellent performance for isoniazid and rifampicin, with sensitivity and specificity values > 90%. With most of the assays, sensitivity for ethambutol was low (62-87% whereas for streptomycin, sensitivity values ranged from 84 to 100%; NRA-discrepancies were associated with cultures with a low proportion of EMB-resistant organisms while most discrepancies with quantitative tests (MMT and BMM were seen with isolates whose minimal inhibitory concentrations fell close the cutoff. MGIT is reliable but still expensive. NRA is the most inexpensive and easiest method to perform without changing the organization of the routine PM laboratory performance. While MODS, MTT, and BMM, have the disadvantage from the point of view of biosafety, they offer the possibility of detecting partial resistant strains. This study shows a very good level of agreement of the four low-cost methods compared to the PM for rapid detection of isoniazid, rifampicin and streptomycin resistance (Kappa values > 0.8; more standardization is needed for ethambutol.

  20. A rapid and efficient method for assessing pathogenicity of ustilago maydis on maize and teosinte lines.

    Science.gov (United States)

    Chavan, Suchitra; Smith, Shavannor M

    2014-01-03

    Maize is a major cereal crop worldwide. However, susceptibility to biotrophic pathogens is the primary constraint to increasing productivity. U. maydis is a biotrophic fungal pathogen and the causal agent of corn smut on maize. This disease is responsible for significant yield losses of approximately $1.0 billion annually in the U.S.(1) Several methods including crop rotation, fungicide application and seed treatments are currently used to control corn smut(2). However, host resistance is the only practical method for managing corn smut. Identification of crop plants including maize, wheat, and rice that are resistant to various biotrophic pathogens has significantly decreased yield losses annually(3-5). Therefore, the use of a pathogen inoculation method that efficiently and reproducibly delivers the pathogen in between the plant leaves, would facilitate the rapid identification of maize lines that are resistant to U. maydis. As, a first step toward indentifying maize lines that are resistant to U. maydis, a needle injection inoculation method and a resistance reaction screening method was utilized to inoculate maize, teosinte, and maize x teosinte introgression lines with a U. maydis strain and to select resistant plants. Maize, teosinte and maize x teosinte introgression lines, consisting of about 700 plants, were planted, inoculated with a strain of U. maydis, and screened for resistance. The inoculation and screening methods successfully identified three teosinte lines resistant to U. maydis. Here a detailed needle injection inoculation and resistance reaction screening protocol for maize, teosinte, and maize x teosinte introgression lines is presented. This study demonstrates that needle injection inoculation is an invaluable tool in agriculture that can efficiently deliver U. maydis in between the plant leaves and has provided plant lines that are resistant to U. maydis that can now be combined and tested in breeding programs for improved disease resistance.

  1. A method for rapid measurement of laser ablation rate of hard dental tissue

    Science.gov (United States)

    Perhavec, T.; Gorkič, A.; Bračun, D.; Diaci, J.

    2009-06-01

    The aim of the study reported here is the development of a new method which allows rapid and accurate in-vitro measurements of three-dimensional (3D) shape of laser ablated craters in hard dental tissues and the determination of crater volume, ablation rate and speed. The method is based on the optical triangulation principle. A laser sheet projector illuminates the surface of a tooth, mounted on a linear translation stage. As the tooth is moved by the translation stage a fast digital video camera captures series of images of the illuminated surface. The images are analyzed to determine a 3D model of the surface. Custom software is employed to analyze the 3D model and to determine the volume of the ablated craters. Key characteristics of the method are discussed as well as some practical aspects pertinent to its use. The method has been employed in an in-vitro study to examine the ablation rates and speeds of the two main laser types currently employed in dentistry, Er:YAG and Er,Cr:YSGG. Ten samples of extracted human molar teeth were irradiated with laser pulse energies from 80 mJ to the maximum available energy (970 mJ with the Er:YAG, and 260 mJ with the Er,Cr:YSGG). About 2000 images of each ablated tooth surface have been acquired along a translation range of 10 mm, taking about 10 s and providing close to 1 million surface measurement points. Volumes of 170 ablated craters (half of them in dentine and the other half in enamel) were determined from this data and used to examine the ablated volume per pulse energy and ablation speed. The results show that, under the same conditions, the ablated volume per pulse energy achieved by the Er:YAG laser exceeds that of the Er,Cr:YSGG laser in almost all regimes for dentine and enamel. The maximum Er:YAG laser ablation speeds (1.2 mm 3/s in dentine and 0.7 mm 3/s in enamel) exceed those obtained by the Er,Cr:YSGG laser (0.39 mm 3/s in dentine and 0.12 mm 3/s in enamel). Since the presented method proves to be easy to

  2. Rapid, convenient method for screening imidazole-containing compounds for heme oxygenase inhibition.

    Science.gov (United States)

    Vlahakis, Jason Z; Rahman, Mona N; Roman, Gheorghe; Jia, Zongchao; Nakatsu, Kanji; Szarek, Walter A

    2011-01-01

    Sensitive assays for measuring heme oxygenase activity have been based on the gas-chromatographic detection of carbon monoxide using elaborate, expensive equipment. The present study describes a rapid and convenient method for screening imidazole-containing candidates for inhibitory activity against heme oxygenase using a plate reader, based on the spectroscopic evaluation of heme degradation. A PowerWave XS plate reader was used to monitor the absorbance (as a function of time) of heme bound to purified truncated human heme oxygenase-1 (hHO-1) in the individual wells of a standard 96-well plate (with or without the addition of a test compound). The degradation of heme by heme oxygenase-1 was initiated using l-ascorbic acid, and the collected relevant absorbance data were analyzed by three different methods to calculate the percent control activity occurring in wells containing test compounds relative to that occurring in control wells with no test compound present. In the cases of wells containing inhibitory compounds, significant shifts in λ(max) from 404 to near 412 nm were observed as well as a decrease in the rate of heme degradation relative to that of the control. Each of the three methods of data processing (overall percent drop in absorbance over 1.5h, initial rate of reaction determined over the first 5 min, and estimated pseudo first-order reaction rate constant determined over 1.5h) gave similar and reproducible results for percent control activity. The fastest and easiest method of data analysis was determined to be that using initial rates, involving data acquisition for only 5 min once reactions have been initiated using l-ascorbic acid. The results of the study demonstrate that this simple assay based on the spectroscopic detection of heme represents a rapid, convenient method to determine the relative inhibitory activity of candidate compounds, and is useful in quickly screening a series or library of compounds for heme oxygenase inhibition

  3. A rapid method of fruit cell isolation for cell size and shape measurements

    Directory of Open Access Journals (Sweden)

    Johnston Jason W

    2009-04-01

    Full Text Available Abstract Background Cell size is a structural component of fleshy fruit, contributing to important traits such as fruit size and texture. There are currently a number of methods for measuring cell size; most rely either on tissue sectioning or digestion of the tissue with cell wall degrading enzymes or chemicals to release single cells. Neither of these approaches is ideal for assaying large fruit numbers as both require a considerable time to prepare the tissue, with current methods of cell wall digestions taking 24 to 48 hours. Additionally, sectioning can lead to a measurement of a plane that does not represent the widest point of the cell. Results To develop a more rapid way of measuring fruit cell size we have developed a protocol that solubilises pectin in the middle lamella of the plant cell wall releasing single cells into a buffered solution. Gently boiling small fruit samples in a 0.05 M Na2CO3 solution, osmotically balanced with 0.3 M mannitol, produced good cell separation with little cellular damage in less than 30 minutes. The advantage of combining a chemical treatment with boiling is that the cells are rapidly killed. This stopped cell shape changes that could potentially occur during separation. With this method both the rounded and angular cells of the apple cultivars SciRos 'Pacific Rose' and SciFresh 'Jazz'™ were observed in the separated cells. Using this technique, an in-depth analysis was performed measuring cell size from 5 different apple cultivars. Cell size was measured using the public domain ImageJ software. For each cultivar a minimum of 1000 cells were measured and it was found that each cultivar displayed a different distribution of cell size. Cell size within cultivars was similar and there was no correlation between flesh firmness and cell size. This protocol was tested on tissue from other fleshy fruit including tomato, rock melon and kiwifruit. It was found that good cell separation was achieved with flesh

  4. Use of predictive models and rapid methods to nowcast bacteria levels at coastal beaches

    Science.gov (United States)

    Francy, Donna S.

    2009-01-01

    The need for rapid assessments of recreational water quality to better protect public health is well accepted throughout the research and regulatory communities. Rapid analytical methods, such as quantitative polymerase chain reaction (qPCR) and immunomagnetic separation/adenosine triphosphate (ATP) analysis, are being tested but are not yet ready for widespread use.Another solution is the use of predictive models, wherein variable(s) that are easily and quickly measured are surrogates for concentrations of fecal-indicator bacteria. Rainfall-based alerts, the simplest type of model, have been used by several communities for a number of years. Deterministic models use mathematical representations of the processes that affect bacteria concentrations; this type of model is being used for beach-closure decisions at one location in the USA. Multivariable statistical models are being developed and tested in many areas of the USA; however, they are only used in three areas of the Great Lakes to aid in notifications of beach advisories or closings. These “operational” statistical models can result in more accurate assessments of recreational water quality than use of the previous day's Escherichia coli (E. coli)concentration as determined by traditional culture methods. The Ohio Nowcast, at Huntington Beach, Bay Village, Ohio, is described in this paper as an example of an operational statistical model. Because predictive modeling is a dynamic process, water-resource managers continue to collect additional data to improve the predictive ability of the nowcast and expand the nowcast to other Ohio beaches and a recreational river. Although predictive models have been shown to work well at some beaches and are becoming more widely accepted, implementation in many areas is limited by funding, lack of coordinated technical leadership, and lack of supporting epidemiological data.

  5. Rapid radiometric methods to detect and differentiate Mycobacterium tuberculosis/M. bovis from other mycobacterial species

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqi, S.H.; Hwangbo, C.C.; Silcox, V.; Good, R.C.; Snider, D.E. Jr.; Middlebrook, G.

    1984-10-01

    Rapid methods for the differentiation of Mycobacterium tuberculosis/M. bovis (TB complex) from other mycobacteria (MOTT bacilli) were developed and evaluated in a three-phase study. In the first phase, techniques for identification of Mycobacterium species were developed by using radiometric technology and BACTEC Middlebrook 7H12 liquid medium. Based on /sup 14/CO/sub 2/ evolution, characteristic growth patterns were established for 13 commonly encountered mycobacterial species. Mycobacteria belonging to the TB complex were differentiated from other mycobacteria by cellular morphology and rate of /sup 14/CO/sub 2/ evolution. For further differentiation, radiometric tests for niacin production and inhibition by Q-nitro-alpha-acetyl amino-beta-hydroxy-propiophenone (NAP) were developed. In the second phase, 100 coded specimens on Lowenstein-Jensen medium were identified as members of the TB complex, MOTT bacilli, bacteria other than mycobacteria, or ''no viable organisms'' within 3 to 12 (average 6.4) days of receipt from the Centers for Disease Control. Isolation and identification of mycobacteria from 20 simulated sputum specimens were carried out in phase III. Out of 20 sputum specimens, 16 contained culturable mycobacteria, and all of the positives were detected by the BACTEC method in an average of 7.3 days. The positive mycobacterial cultures were isolated and identified as TB complex or MOTT bacilli in an average of 12.8 days. The radiometric NAP test was found to be highly sensitive and specific for a rapid identification of TB complex, whereas the radiometric niacin test was found to have some inherent problems. Radiometric BACTEC and conventional methodologies were in complete agreement in Phase II as well as in Phase III.

  6. A rapid minor groove binder PCR method for distinguishing the vaccine strain Brucella abortus 104M.

    Science.gov (United States)

    Nan, Wenlong; Qin, Lide; Wang, Yong; Zhang, Yueyong; Tan, Pengfei; Chen, Yuqi; Mao, Kairong; Chen, Yiping

    2018-01-24

    Brucellosis is a widespread zoonotic disease caused by Gram-negative Brucella bacteria. Immunisation with attenuated vaccine is an effective method of prevention, but it can interfere with diagnosis. Live, attenuated Brucella abortus strain 104M has been used for the prevention of human brucellosis in China since 1965. However, at present, no fast and reliable method exists that can distinguish this strain from field strains. Single nucleotide polymorphism (SNP)-based assays offer a new approach for such discrimination. SNP-based minor groove binder (MGB) and Cycleave assays have been used for rapid identification of four Brucella vaccine strains (B. abortus strains S19, A19 and RB51, and B. melitensis Rev1). The main objective of this study was to develop a PCR assay for rapid and specific detection of strain 104M. We developed a SNP-based MGB PCR assay that could successfully distinguish strain 104M from 18 representative strains of Brucella (B. abortus biovars 1, 2, 3, 4, 5, 6, 7 and 9, B. melitensis biovars 1, 2 and 3, B. suis biovars 1, 2, 3 and 4, B. canis, B. neotomae, and B. ovis), four Brucella vaccine strains (A19, S19, S2, M5), and 55 Brucella clinical field strains. The assay gave a negative reaction with four non-Brucella species (Escherichia coli, Pasteurella multocida, Streptococcus suis and Pseudomonas aeruginosa). The minimum sensitivity of the assay, evaluated using 10-fold dilutions of chromosomal DNA, was 220 fg for the 104M strain and 76 fg for the single non-104M Brucella strain tested (B. abortus A19). The assay was also reproducible (intra- and inter-assay coefficients of variation = 0.006-0.022 and 0.012-0.044, respectively). A SNP-based MGB PCR assay was developed that could straightforwardly and unambiguously distinguish B. abortus vaccine strain 104M from non-104M Brucella strains. Compared to the classical isolation and identification approaches of bacteriology, this real-time PCR assay has substantial advantages in terms of

  7. A Method for Rapid Measurement of Contrast Sensitivity on Mobile Touch-Screens

    Science.gov (United States)

    Mulligan, Jeffrey B.

    2016-01-01

    Touch-screen displays in cell phones and tablet computers are now pervasive, making them an attractive option for vision testing outside of the laboratory or clinic. Here we de- scribe a novel method in which subjects use a finger swipe to indicate the transition from visible to invisible on a grating which is swept in both contrast and frequency. Because a single image can be swiped in about a second, it is practical to use a series of images to zoom in on particular ranges of contrast or frequency, both to increase the accuracy of the measurements and to obtain an estimate of the reliability of the subject. Sensitivities to chromatic and spatio-temporal modulations are easily measured using the same method. A proto- type has been developed for Apple Computer's iPad/iPod/iPhone family of devices, implemented using an open-source scripting environment known as QuIP (QUick Image Processing, http://hsi.arc.nasa.gov/groups/scanpath/research.php). Preliminary data show good agreement with estimates obtained from traditional psychophysical methods as well as newer rapid estimation techniques. Issues relating to device calibration are also discussed.

  8. Modified agar dilution method for rapid antibiotic susceptibility testing of anaerobic bacteria.

    Science.gov (United States)

    Hanson, C W; Martin, W J

    1978-01-01

    A simplified method has been developed for agar dilution antimicrobial susceptibility testing of anaerobic bacteria, designed to economize on time and money when only a few isolates need to be tested. The procedure is based on the principle of using filter paper disks as carriers of the antibiotic and 35- by 10-mm petri dishes which, when inoculated with the Steers replicator, can test up to four organisms per plate. The procedure was run in parallel with conventional agar dilution techniques and showed 95% agreement to within one dilution for all minimal inhibitory concentrations recorded on fresh anaerobic isolates from clinical specimens. The technique was further simplified by using commercially available antibiotic-containing disks, thereby alleviating the tedious and time-consuming procedure of preparing the disks. The data indicated that 48- to 72-h diffusion periods were sufficient to achieve a uniform concentration of the antibiotic in the petri plate and that the antibiotics were stable at room temperature for that period of time. In terms of applicability and relevance to the needs of the clinical microbiology laboratory, the modified agar dilution method for rapid antimicrobial susceptibility testing of individual anaerobic isolates was found to be superior to the broth dilution method since it was easier to read and required considerably less set up time. PMID:400819

  9. Development of a rapid HRM genotyping method for detection of dog-derived Giardia lamblia.

    Science.gov (United States)

    Tan, Liping; Yu, Xingang; Abdullahi, Auwalu Yusuf; Wu, Sheng; Zheng, Guochao; Hu, Wei; Song, Meiran; Wang, Zhen; Jiang, Biao; Li, Guoqing

    2015-11-01

    Giardia lamblia is a zoonotic flagellate protozoan in the intestine of human and many mammals including dogs. To assess a threat of dog-derived G. lamblia to humans, the common dog-derived G. lamblia assemblages A, C, and D were genotyped by high-resolution melting (HRM) technology. According to β-giardin gene sequence, the qPCR-HRM primers BG5 and BG7 were designed. A series of experiments on the stability, sensitivity, and accuracy of the HRM method were also tested. Results showed that the primers BG5 and BG7 could distinguish among three assemblages A, C, and D, which Tm value differences were about 1 °C to each other. The melting curves of intra-assay reproducibility were almost coincided, and those of inter-assay reproducibility were much the same shape. The lowest detection concentration was about 5 × 10(-6)-ng/μL sample. The genotyping results from 21 G. lamblia samples by the HRM method were in complete accordance with sequencing results. It is concluded that the HRM genotyping method is rapid, stable, specific, highly sensitive, and suitable for clinical detection and molecular epidemiological survey of dog-derived G. lamblia.

  10. Rapid, high-temperature, field test method for evaluation of geothermal calcium carbonate scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.

    1986-09-01

    A new test method is described that allows the rapid field testing of calcium carbonate scale inhibitors at 500/sup 0/F (260/sup 0/C). The method evolved from use of a full-flow test loop on a well with a mass flow rate of about 1 x 10/sup 6/ lbm/hr (126 kg/s). It is a simple, effective way to evaluate the effectiveness of inhibitors under field conditions. Five commercial formulations were chosen for field evaluation on the basis of nonflowing, laboratory screening tests at 500/sup 0/F (260/sup 0/C). Four of these formulations from different suppliers controlled calcium carbonate scale deposition as measured by the test method. Two of these could dislodge recently deposited scale that had not age-hardened. Performance-profile diagrams, which were measured for these four effective inhibitors, show the concentration interrelationship between brine calcium and inhibitor concentrations at which the formulations will and will not stop scale formation in the test apparatus. With these diagrams, one formulation was chosen for testing on the full-flow brine line. The composition was tested for 6 weeks and showed a dramatic decrease in the scaling occurring at the flow-control valve. This scaling was about to force a shutdown of a major, long-term flow test being done for reservoir economic evaluations. The inhibitor stopped the scaling, and the test was performed without interruption.

  11. A simple and rapid cultural method for detection of Enterobacter sakazakii in environmental samples.

    Science.gov (United States)

    Guillaume-Gentil, O; Sonnard, V; Kandhai, M C; Marugg, J D; Joosten, H

    2005-01-01

    A method was developed to detect and identify Enterobacter sakazakii in environmental samples. The method is based on selective enrichment at 45+/-0.5 degrees C in lauryl sulfate tryptose broth supplemented with 0.5 M NaCl and 10 mg/liter vancomycin (mLST) for 22 to 24 h followed by streaking on tryptone soy agar with bile salts. When exposed to light during incubation at 37 degrees C, E. sakazakii produces yellow colonies within 24 h; identification was confirmed by testing for alpha-glucosidase activity and by using API 20E strips. All of the E. sakazakii strains tested (n = 99) were able to grow in mLST at 45+/-0.5 degrees C, whereas 35 of 39 strains of potential competitors, all belonging to the Enterobacteriaceae, were suppressed. A survey was carried out with 192 environmental samples from four different milk powder factories. Using this new protocol, E. sakazakii was isolated from almost 40% of the samples, whereas the reference procedure (enrichment in buffered peptone water, isolation on violet red bile glucose agar, and biochemical identification of randomly chosen colonies) only yielded 26% positive results. This selective method can be very useful for the rapid and reliable detection of E. sakazakii in environmental samples.

  12. Rapid, Simple, and Sensitive Spectrofluorimetric Method for the Estimation of Ganciclovir in Bulk and Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    Garima Balwani

    2013-01-01

    Full Text Available A new, simple, rapid, sensitive, accurate, and affordable spectrofluorimetric method was developed and validated for the estimation of ganciclovir in bulk as well as in marketed formulations. The method was based on measuring the native fluorescence of ganciclovir in 0.2 M hydrochloric acid buffer of pH 1.2 at 374 nm after excitation at 257 nm. The calibration graph was found to be rectilinear in the concentration range of 0.25–2.00 μg mL−1. The limit of quantification and limit of detection were found to be 0.029 μg mL−1 and 0.010 μg mL−1, respectively. The method was fully validated for various parameters according to ICH guidelines. The results demonstrated that the procedure is accurate, precise, and reproducible (relative standard deviation <2% and can be successfully applied for the determination of ganciclovir in its commercial capsules with average percentage recovery of 101.31 ± 0.90.

  13. Rapid Method for the Determination of the Stable Oxygen Isotope Ratio of Water in Alcoholic Beverages.

    Science.gov (United States)

    Wang, Daobing; Zhong, Qiding; Li, Guohui; Huang, Zhanbin

    2015-10-28

    This paper demonstrates the first successful application of an online pyrolysis technique for the direct determination of oxygen isotope ratios (δ(18)O) of water in alcoholic beverages. Similar water concentrations in each sample were achieved by adjustment with absolute ethyl alcohol, and then a fixed GC split ratio can be used. All of the organic ingredients were successfully separated from the analyte on a CP-PoraBond Q column and subsequently vented out, whereas water molecules were transferred into the reaction furnace and converted to CO. With the system presented, 15-30 μL of raw sample was diluted and can be analyzed repeatedly; the analytical precision was better than 0.4‰ (n = 5) in all cases, and more than 50 injections can be made per day. No apparent memory effect was observed even if water samples were injected using the same syringe; a strong correlation (R(2) = 0.9998) was found between the water δ(18)O of measured sample and that of working standards. There was no significant difference (p > 0.05) between the mean δ(18)O value and that obtained by the traditional method (CO2-water equilibration/isotope ratio mass spectrometry) and the newly developed method in this study. The advantages of this new method are its rapidity and straightforwardness, and less test portion is required.

  14. A rapid and efficient electroporation method for transformation of Halomonas sp. O-1.

    Science.gov (United States)

    Harris, Joshua R; Lundgren, Benjamin R; Grzeskowiak, Brian R; Mizuno, Kouhei; Nomura, Christopher T

    2016-10-01

    Halomonas sp. O-1 is a halophilic bacterium with a high potential for industrial application due to its natural ability to produce polyhydroxyalkanoates (PHAs) using seawater-based media. However, a major barrier preventing industrial scale implementation of this organism is a lack of molecular methodologies capable of readily transforming members of the Halomonas genus. Currently, the only reliable method used for introducing DNA into Halomonas spp. is bacterial conjugation, a somewhat tedious and time-consuming technique compared to electroporation-based methodologies. Here we describe a rapid and reproducible method for the electroporation of Halomonas sp. O-1 with plasmid DNA. Electrocompetent cells were generated by growing Halomonas sp. O-1 in a yeast extract-tryptone medium with a final salinity of 3.5%, pH of 7.5, followed by several washes using 300mM sucrose. Results show that plasmids containing chloramphenicol (Cm(R)) and gentamicin (Gm(R)) resistance cassettes are suitable antibiotic selection markers for transformation and yields of 10(4) transformants per μg of DNA were obtained. This method is simple to perform and the materials used are readily available in most research labs. Additionally, this plasmid-based transformation procedure has the potential to be adapted for a number of applications including the creation of recombinant stains and the generation of deletion mutants of Halomonas spp. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. A Rapid and Sensitive Method to Measure the Functional Activity of Shiga Toxins in Human Serum

    Directory of Open Access Journals (Sweden)

    Valentina Arfilli

    2015-11-01

    Full Text Available Shiga toxins (Stx have a definite role in the development of hemolytic uremic syndrome in children with hemorrhagic colitis caused by pathogenic Stx-producing Escherichia coli (STEC strains. The dramatic effects of these toxins on the microvasculature of different organs, particularly of the kidney, are well known, whereas there is no consensus on the mechanism by which Stx reach the endothelia of target organs and/or indirectly injure these body sites. We hereby describe a quick (4 h, radioactive, Raji cell-based method designed for the detection of Stx in human sera. The assay monitors the translation impairment induced by these powerful inhibitors of protein synthesis, which are identified properly by neutralizing their activity with specific monoclonal antibodies. By this method, we detected for the first time the functional activity of Stx in sera of STEC-infected patients during hemorrhagic colitis. Recent research has pointed to a dynamic process of Stx-induced renal intoxication in which concurrent and interactive steps are involved. Our rapid and specific method could be useful for studying the kinetics of Stx during the natural course of STEC infection and the interplay between Stx activity in serum and Stx presence in different blood fractions (neutrophils, monocytes, platelets, leukocyte-platelet aggregates, microvesicles, lipoproteins.

  16. FLASH: A rapid method for prototyping paper-based microfluidic devices‡

    Science.gov (United States)

    Martinez, Andres W.; Phillips, Scott T.; Wiley, Benjamin J.; Gupta, Malancha

    2011-01-01

    This article describes FLASH (Fast Lithographic Activation of Sheets), a rapid method for laboratory prototyping of microfluidic devices in paper. Paper-based microfluidic devices are emerging as a new technology for applications in diagnostics for the developing world, where low cost and simplicity are essential. FLASH is based on photolithography, but requires only a UV lamp and a hotplate; no clean-room or special facilities are required (FLASH patterning can even be performed in sunlight if a UV lamp and hotplate are unavailable). The method provides channels in paper with dimensions as small as 200 μm in width and 70 μm in height; the height is defined by the thickness of the paper. Photomasks for patterning paper-based microfluidic devices can be printed using an ink-jet printer or photocopier, or drawn by hand using a waterproof black pen. FLASH provides a straightforward method for prototyping paper-based microfluidic devices in regions where the technological support for conventional photolithography is not available. PMID:19023478

  17. AO–MW–PLS method applied to rapid quantification of teicoplanin with near-infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Jiemei Chen

    2017-01-01

    Full Text Available Teicoplanin (TCP is an important lipoglycopeptide antibiotic produced by fermenting Actinoplanes teichomyceticus. The change in TCP concentration is important to measure in the fermentation process. In this study, a reagent-free and rapid quantification method for TCP in the TCP–Tris–HCl mixture samples was developed using near-infrared (NIR spectroscopy by focusing our attention on the fermentation process for TCP. The absorbance optimization (AO partial least squares (PLS was proposed and integrated with the moving window (MW PLS, which is called AO–MW–PLS method, to select appropriate wavebands. A model set that includes various wavebands that were equivalent to the optimal AO–MW–PLS waveband was proposed based on statistical considerations. The public region of all equivalent wavebands was just one of the equivalent wavebands. The obtained public regions were 1540–1868nm for TCP and 1114–1310nm for Tris. The root-mean-square error and correlation coefficient for leave-one-out cross validation were 0.046mg mL−1 and 0.9998mg mL−1 for TCP, and 0.235mg mL−1 and 0.9986mg mL−1 for Tris, respectively. All the models achieved highly accurate prediction effects, and the selected wavebands provided valuable references for designing specialized spectrometers. This study provided a valuable reference for further application of the proposed methods to TCP fermentation broth and to other spectroscopic analysis fields.

  18. A simple electrochemical method for the rapid estimation of antioxidant potentials of some selected medicinal plants.

    Science.gov (United States)

    Amidi, Salimeh; Mojab, Faraz; Bayandori Moghaddam, Abdolmajid; Tabib, Kimia; Kobarfard, Farzad

    2012-01-01

    Clinical and Epidemiological studies have shown that a diet rich in fruits and vegetables is associated with a decreased risk of cardiovascular diseases, cancers and other related disorders. These beneficial health effects have been attributed in part to the presence of antioxidants in dietary plants. Therefore screening for antioxidant properties of plant extracts has been one of the interests of scientists in this field. Different screening methods have been reported for the evaluation of antioxidant properties of plant extracts in the literature. In the present research a rapid screening method has been introduced based on cyclic voltammetry for antioxidant screening of some selected medicinal plant extracts. CYCLIC VOLTAMMETRY OF METHANOLIC EXTRACTS OF SEVEN MEDICINAL PLANTS: Buxus hyrcana, Rumex crispus, Achillea millefolium, Zataria multiflora, Ginkgo biloba, Lippia citriodora and Heptaptera anisoptera was carried out at different scan rates. Based on the interpretation of voltammograms, Rumex crispus, Achillea millefolium and Ginkgo biloba showed higher antioxidant capability than the others while Lippia citriodora contained the highest amount of antioxidants. Cyclic voltammetry is expected to be a simple method for screening antioxidants and estimating the antioxidant activity of foods and medicinal plants.

  19. A Rapid and Sensitive Method to Measure the Functional Activity of Shiga Toxins in Human Serum

    Science.gov (United States)

    Arfilli, Valentina; Carnicelli, Domenica; Ardissino, Gianluigi; Torresani, Erminio; Scavia, Gaia; Brigotti, Maurizio

    2015-01-01

    Shiga toxins (Stx) have a definite role in the development of hemolytic uremic syndrome in children with hemorrhagic colitis caused by pathogenic Stx-producing Escherichia coli (STEC) strains. The dramatic effects of these toxins on the microvasculature of different organs, particularly of the kidney, are well known, whereas there is no consensus on the mechanism by which Stx reach the endothelia of target organs and/or indirectly injure these body sites. We hereby describe a quick (4 h), radioactive, Raji cell-based method designed for the detection of Stx in human sera. The assay monitors the translation impairment induced by these powerful inhibitors of protein synthesis, which are identified properly by neutralizing their activity with specific monoclonal antibodies. By this method, we detected for the first time the functional activity of Stx in sera of STEC-infected patients during hemorrhagic colitis. Recent research has pointed to a dynamic process of Stx-induced renal intoxication in which concurrent and interactive steps are involved. Our rapid and specific method could be useful for studying the kinetics of Stx during the natural course of STEC infection and the interplay between Stx activity in serum and Stx presence in different blood fractions (neutrophils, monocytes, platelets, leukocyte-platelet aggregates, microvesicles, lipoproteins). PMID:26556372

  20. Rapid and sensitive method for determination of withaferin-A in human plasma by HPLC.

    Science.gov (United States)

    Patial, Pankaj; Gota, Vikram

    2011-02-01

    To develop and validate a rapid and sensitive high-performance liquid chromatographic method for determination of withaferin-A in human plasma. Withaferin-A, the active molecule of a traditional Indian herb, has demonstrated several biological activities in preclinical models. A validated bioassay is not available for its pharmacokinetic evaluation. The chromatographic system used a reverse-phase C18 column with UV-visible detection at 225 nm. The mobile phase consisted of water and acetonitrile applied in a gradient flow. Withaferin-A was extracted by simple protein-precipitation technique. The calibration curve was linear in the concentration range of 0.05-1.6 µg/ml. The method has the desired sensitivity to detect the plasma concentration range of withaferin-A that is likely to show biological activity based on in vitro data. This is the first HPLC method ever described for the estimation of withaferin-A in human plasma which could be applied for pharmacokinetic studies.

  1. Basic design principles of colorimetric vision systems

    Science.gov (United States)

    Mumzhiu, Alex M.

    1998-10-01

    Color measurement is an important part of overall production quality control in textile, coating, plastics, food, paper and other industries. The color measurement instruments such as colorimeters and spectrophotometers, used for production quality control have many limitations. In many applications they cannot be used for a variety of reasons and have to be replaced with human operators. Machine vision has great potential for color measurement. The components for color machine vision systems, such as broadcast quality 3-CCD cameras, fast and inexpensive PCI frame grabbers, and sophisticated image processing software packages are available. However the machine vision industry has only started to approach the color domain. The few color machine vision systems on the market, produced by the largest machine vision manufacturers have very limited capabilities. A lack of understanding that a vision based color measurement system could fail if it ignores the basic principles of colorimetry is the main reason for the slow progress of color vision systems. the purpose of this paper is to clarify how color measurement principles have to be applied to vision systems and how the electro-optical design features of colorimeters have to be modified in order to implement them for vision systems. The subject of this presentation far exceeds the limitations of a journal paper so only the most important aspects will be discussed. An overview of the major areas of applications for colorimetric vision system will be discussed. Finally, the reasons why some customers are happy with their vision systems and some are not will be analyzed.

  2. Improved detection of chemical substances from colorimetric sensor data using probabilistic machine learning

    Science.gov (United States)

    Mølgaard, Lasse L.; Buus, Ole T.; Larsen, Jan; Babamoradi, Hamid; Thygesen, Ida L.; Laustsen, Milan; Munk, Jens Kristian; Dossi, Eleftheria; O'Keeffe, Caroline; Lässig, Lina; Tatlow, Sol; Sandström, Lars; Jakobsen, Mogens H.

    2017-05-01

    We present a data-driven machine learning approach to detect drug- and explosives-precursors using colorimetric sensor technology for air-sampling. The sensing technology has been developed in the context of the CRIM-TRACK project. At present a fully- integrated portable prototype for air sampling with disposable sensing chips and automated data acquisition has been developed. The prototype allows for fast, user-friendly sampling, which has made it possible to produce large datasets of colorimetric data for different target analytes in laboratory and simulated real-world application scenarios. To make use of the highly multi-variate data produced from the colorimetric chip a number of machine learning techniques are employed to provide reliable classification of target analytes from confounders found in the air streams. We demonstrate that a data-driven machine learning method using dimensionality reduction in combination with a probabilistic classifier makes it possible to produce informative features and a high detection rate of analytes. Furthermore, the probabilistic machine learning approach provides a means of automatically identifying unreliable measurements that could produce false predictions. The robustness of the colorimetric sensor has been evaluated in a series of experiments focusing on the amphetamine pre-cursor phenylacetone as well as the improvised explosives pre-cursor hydrogen peroxide. The analysis demonstrates that the system is able to detect analytes in clean air and mixed with substances that occur naturally in real-world sampling scenarios. The technology under development in CRIM-TRACK has the potential as an effective tool to control trafficking of illegal drugs, explosive detection, or in other law enforcement applications.

  3. Validity and feasibility of a satellite imagery-based method for rapid estimation of displaced populations

    Directory of Open Access Journals (Sweden)

    Checchi Francesco

    2013-01-01

    Full Text Available Abstract Background Estimating the size of forcibly displaced populations is key to documenting their plight and allocating sufficient resources to their assistance, but is often not done, particularly during the acute phase of displacement, due to methodological challenges and inaccessibility. In this study, we explored the potential use of very high resolution satellite imagery to remotely estimate forcibly displaced populations. Methods Our method consisted of multiplying (i manual counts of assumed residential structures on a satellite image and (ii estimates of the mean number of people per structure (structure occupancy obtained from publicly available reports. We computed population estimates for 11 sites in Bangladesh, Chad, Democratic Republic of Congo, Ethiopia, Haiti, Kenya and Mozambique (six refugee camps, three internally displaced persons’ camps and two urban neighbourhoods with a mixture of residents and displaced ranging in population from 1,969 to 90,547, and compared these to “gold standard” reference population figures from census or other robust methods. Results Structure counts by independent analysts were reasonably consistent. Between one and 11 occupancy reports were available per site and most of these reported people per household rather than per structure. The imagery-based method had a precision relative to reference population figures of Conclusions In settings with clearly distinguishable individual structures, the remote, imagery-based method had reasonable accuracy for the purposes of rapid estimation, was simple and quick to implement, and would likely perform better in more current application. However, it may have insurmountable limitations in settings featuring connected buildings or shelters, a complex pattern of roofs and multi-level buildings. Based on these results, we discuss possible ways forward for the method’s development.

  4. A method for rapid measurement of intrarenal and other tissue pressures.

    Science.gov (United States)

    SWANN, H G; MONTGOMERY, A V; DAVIS, J C; MICKLE, E R

    1950-12-01

    A rapid method for measuring tissue pressures has been designed. A pressure of 250 mm. Hg is imposed on a manometer. Then the system is allowed to discharge into a needle cannula inserted in the tissue. The manometer forces out fluid (about 10 c.mm.) until the pressure within it is the same as that within the tissue. Records of the pressure changes are made. Each observation takes about a minute. The method gives results that are closely comparable with other reports of tissue pressures. With this method, the pressure in the following organs of dogs was found to be: kidney, 26 mm. Hg, cerebral cortex, 0 to 5 mm., muscle, 1 to 10 mm., spleen, S to 16 mm., subcutaneous tissue, 0 to 3 mm., and liver -2 to 14 mm. The reliability of the method was tested on the kidneys of decerebrate dogs. Measurements were found to be the same within narrow limits over a period of an hour; they were the same when taken simultaneously in different regions of the same kidney or in opposite kidneys. They were independent of the volume of fluid forced into the tissue. Similar pressures were observed with 1 or 5 or 10 holes bored in the shaft of the cannulating needle. The intrarenal pressure was also measured by inserting a needle cannula into the tissue and then allowing the pressure to reach equilibrium passively with a manometer. This method gave similar results. The intrarenal pressure has now found to be the same when measured by three different technics.

  5. Improved Savitzky-Golay-method-based fluorescence subtraction algorithm for rapid recovery of Raman spectra.

    Science.gov (United States)

    Chen, Kun; Zhang, Hongyuan; Wei, Haoyun; Li, Yan

    2014-08-20

    In this paper, we propose an improved subtraction algorithm for rapid recovery of Raman spectra that can substantially reduce the computation time. This algorithm is based on an improved Savitzky-Golay (SG) iterative smoothing method, which involves two key novel approaches: (a) the use of the Gauss-Seidel method and (b) the introduction of a relaxation factor into the iterative procedure. By applying a novel successive relaxation (SG-SR) iterative method to the relaxation factor, additional improvement in the convergence speed over the standard Savitzky-Golay procedure is realized. The proposed improved algorithm (the RIA-SG-SR algorithm), which uses SG-SR-based iteration instead of Savitzky-Golay iteration, has been optimized and validated with a mathematically simulated Raman spectrum, as well as experimentally measured Raman spectra from non-biological and biological samples. The method results in a significant reduction in computing cost while yielding consistent rejection of fluorescence and noise for spectra with low signal-to-fluorescence ratios and varied baselines. In the simulation, RIA-SG-SR achieved 1 order of magnitude improvement in iteration number and 2 orders of magnitude improvement in computation time compared with the range-independent background-subtraction algorithm (RIA). Furthermore the computation time of the experimentally measured raw Raman spectrum processing from skin tissue decreased from 6.72 to 0.094 s. In general, the processing of the SG-SR method can be conducted within dozens of milliseconds, which can provide a real-time procedure in practical situations.

  6. A Rapid Method for Quantifying Viable Mycobacterium avium subsp. paratuberculosis in Cellular Infection Assays

    Science.gov (United States)

    Pooley, Hannah B.; de Silva, Kumudika; Purdie, Auriol C.; Begg, Douglas J.; Whittington, Richard J.

    2016-01-01

    ABSTRACT Determining the viability of bacteria is a key outcome of in vitro cellular infection assays. Currently, this is done by culture, which is problematic for fastidious slow-growing bacteria such as Mycobacterium avium subsp. paratuberculosis, where it can take up to 4 months to confirm growth. This study aimed to identify an assay that can rapidly quantify the number of viable M. avium subsp. paratuberculosis cells in a cellular sample. Three commercially available bacterial viability assays along with a modified liquid culture method coupled with high-throughput quantitative PCR growth detection were assessed. Criteria for assessment included the ability of each assay to differentiate live and dead M. avium subsp. paratuberculosis organisms and their accuracy at low bacterial concentrations. Using the culture-based method, M. avium subsp. paratuberculosis growth was reliably detected and quantified within 2 weeks. There was a strong linear association between the 2-week growth rate and the initial inoculum concentration. The number of viable M. avium subsp. paratuberculosis cells in an unknown sample was quantified based on the growth rate, by using growth standards. In contrast, none of the commercially available viability assays were suitable for use with samples from in vitro cellular infection assays. IMPORTANCE Rapid quantification of the viability of Mycobacterium avium subsp. paratuberculosis in samples from in vitro cellular infection assays is important, as it allows these assays to be carried out on a large scale. In vitro cellular infection assays can function as a preliminary screening tool, for vaccine development or antimicrobial screening, and also to extend findings derived from experimental animal trials. Currently, by using culture, it takes up to 4 months to obtain quantifiable results regarding M. avium subsp. paratuberculosis viability after an in vitro infection assay; however, with the quantitative PCR and liquid culture method

  7. Multi-colorimetric sensor array for detection of explosives in gas and liquid phase

    Science.gov (United States)

    Kostesha, N.; Alstrøm, T. S.; Johnsen, C.; Nielsen, K. A.; Jeppesen, J. O.; Larsen, J.; Boisen, A.; Jakobsen, M. H.

    2011-05-01

    In the framework of the research project "Xsense" at the Technical University of Denmark (DTU) we are developing a simple colorimetric sensor array which can be useful in detection of explosives like DNT, TATP, HMX, RDX and identification of reagents needed for making homemade explosives. The technology is based on an array of chemoselective compounds immobilized on a solid support. Upon exposure to the analyte in suspicion the colorimetric array changes color. Each chosen compound reacts chemo-selectively with analytes of interest. A change in a color signature indicates the presence of unknown explosives and volatile organic compounds (VOCs). We are working towards the selection of compounds that undergo color changes in the presence of explosives and VOCs, as well as the development of an immobilization method for the molecules. Digital imaging of the colorimetric array before and after exposure to the analytes creates a color difference map which gives a unique fingerprint for each explosive and VOCs. Such sensing technology can be used for screening relevant explosives in a complex background as well as to distinguish mixtures of volatile organic compounds distributed in gas and liquid phases. This sensor array is inexpensive, and can potentially be produced as single use disposable.

  8. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles.

    Science.gov (United States)

    Nirala, Narsingh R; Saxena, Preeti S; Srivastava, Anchal

    2018-02-05

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles

    Science.gov (United States)

    Nirala, Narsingh R.; Saxena, Preeti S.; Srivastava, Anchal

    2018-02-01

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2 mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19 mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100 mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel.

  10. A Simple and Rapid Identification Method for Mycobacterium bovis BCG with Loop-Mediated Isothermal Amplification.

    Directory of Open Access Journals (Sweden)

    Yuji Kouzaki

    Full Text Available Bacillus Calmette-Guérin (BCG is widely used as a live attenuated vaccine against Mycobacterium tuberculosis and is an agent for standard prophylaxis against the recurrence of bladder cancer. Unfortunately, it can cause severe infectious diseases, especially in immunocompromised patients, and the ability to immediately distinguish BCG from other M. tuberculosis complexes is therefore important. In this study, we developed a simple and easy-to-perform identification procedure using loop-mediated amplification (LAMP to detect deletions within the region of difference, which is deleted specifically in all M. bovis BCG strains. Reactions were performed at 64 °C for 30 min and successful targeted gene amplifications were detected by real-time turbidity using a turbidimeter and visual inspection of color change. The assay had an equivalent detection limit of 1.0 pg of genomic DNA using a turbidimeter whereas it was 10 pg with visual inspection, and it showed specificity against 49 strains of 44 pathogens, including M. tuberculosis complex. The expected LAMP products were confirmed through identical melting curves in real-time LAMP procedures. We employed the Procedure for Ultra Rapid Extraction (PURE kit to isolate mycobacterial DNA and found that the highest sensitivity limit with a minimum total cell count of mycobacterium (including DNA purification with PURE was up to 1 × 10(3 cells/reaction, based on color changes under natural light with FDA reagents. The detection limit of this procedure when applied to artificial serum, urine, cerebrospinal fluid, and bronchoalveolar lavage fluid samples was also about 1 × 10(3 cells/reaction. Therefore, this substitute method using conventional culture or clinical specimens followed by LAMP combined with PURE could be a powerful tool to enable the rapid identification of M. bovis BCG as point-of-care testing. It is suitable for practical use not only in resource-limited situations, but also in any

  11. Development of a fluorescence in situ hybridization (FISH) method for rapid detection of Ulva prolifera

    Science.gov (United States)

    Zhang, Qing-Chun; Liu, Qing; Kang, Zhen-Jun; Yu, Ren-Cheng; Yan, Tian; Zhou, Ming-Jiang

    2015-09-01

    Large-scale green tides have occurred consecutively since 2007 in the Yellow Sea (YS), China. The dominant causative species of the green tides has been identified as Ulva prolifera. The origin of green tides in the YS has been traced back to the Subei Shoal based on the results of remote-sensing, numerical simulations and field investigations. However, it is difficult to study the early development of green tides in the Subei Shoal because of the mixture of multiple green algae and the morphological diversity of U. prolifera when under variable environmental conditions. In this study, a rapid and accurate fluorescence in situ hybridization (FISH) method was developed to detect U. prolifera from the community of green algae targeting the 5S rDNA spacer region of U. prolifera. Two specific probes, 5S-1 and 5S-2, were designed based on the sequences of the 5S rDNA spacer regions of U. prolifera, Ulva linza and Ulva flexuosa. Specificity of the FISH method was tested using the six species of green algae commonly occurring in the Subei Shoal, including U. prolifera, U. linza, U. flexuosa, Ulva compressa, Ulva pertusa and Blidingia sp. The results showed that only U. prolifera could be labeled with both probes. Probe 5S-1, which showed a much higher labeling efficiency on U. prolifera, was ultimately selected as the probe for the FISH detection. The sample preparation method was optimized, particularly for the mature green algae, by the addition of cellulase and proteinase K in the pre-hybridization solution. Labeling efficiency with the probe 5S-1 reached 96% on average under the optimized conditions. The successful development of the FISH method has been applied to qualitative and quantitative analysis of field samples collected from the YS, and the results indicate a potential use in future green algae studies.

  12. A rapid method for the sequential separation of polonium, plutonium, americium and uranium in drinking water.

    Science.gov (United States)

    Lemons, B; Khaing, H; Ward, A; Thakur, P

    2018-02-06

    A new sequential separation method for the determination of polonium and actinides (Pu, Am and U) in drinking water samples has been developed that can be used for emergency response or routine water analyses. For the first time, the application of TEVA chromatography column in the sequential separation of polonium and plutonium has been studied. This method utilizes a rapid Fe +3 co-precipitation step to remove matrix interferences, followed by plutonium oxidation state adjustment to Pu 4+ and an incubation period of ~ 1 h at 50-60 °C to allow Po 2+ to oxidize to Po 4+ . The polonium and plutonium were then separated on a TEVA column, while separation of americium from uranium was performed on a TRU column. After separation, polonium was micro-precipitated with copper sulfide (CuS), while actinides were micro co-precipitated using neodymium fluoride (NdF 3 ) for counting by the alpha spectrometry. The method is simple, robust and can be performed quickly with excellent removal of interferences, high chemical recovery and very good alpha peak resolution. The efficiency and reliability of the procedures were tested by using spiked samples. The effect of several transition metals (Cu 2+ , Pb 2+ , Fe 3+ , Fe 2+ , and Ni 2+ ) on the performance of this method were also assessed to evaluate the potential matrix effects. Studies indicate that presence of up to 25 mg of these cations in the samples had no adverse effect on the recovery or the resolution of polonium alpha peaks. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Veterinary drug residues in meat: Concerns and rapid methods for detection.

    Science.gov (United States)

    Reig, Milagro; Toldrá, Fidel

    2008-01-01

    The use of substances having hormonal or thyreostatic action as well as β-agonists is banned in the European Union. However, sometimes forbidden drugs may be added to feeds for illegal administration to farm animals for promoting increased muscle development or increased water retention and thus obtain an economical benefit. The result is a fraudulent overweight of meat but, what is worse, residues of these substances may remain in meat and may pose a real threat to the consumer either through exposure to the residues, transfer of antibiotic resistance or allergy risk. This has exerted a great concern among European consumers. The control of the absence of these forbidden substances in animal foods and feeds is regulated in the European Union by Directive96/23/EC on measures to monitor certain substances and residues in live animals and animal products. Analytical methodology, including criteria for identification and confirmation, for the monitoring of compliance was also given in Decisions 93/256/EEC and 93/257/EEC. More recently, Decision 2002/657/EC provided rules for the analytical methods to be used in testing of official samples. A crucial step is the screening of veterinary drug residues in live animals, feeds and animal products in view of the remarkable number of samples and large variety of residues to be analysed. In recent years, different rapid methods having easy performance, high sensitivity and high throughput have been proposed and are being extensively used. These methods as well as other new methods are reviewed in this manuscript.

  14. TranScreen-N: Method for rapid screening of trans-ungual drug delivery enhancers.

    Science.gov (United States)

    Murthy, S Narasimha; Vaka, Siva Ram Kiran; Sammeta, Srinivasa Murthy; Nair, Anroop B

    2009-11-01

    Topical monotherapy of nail diseases such as onychomycosis and nail psoriasis has been less successful due to poor permeability of the human nail plate to topically administered drugs. Chemical enhancers are utilized to improve the drug delivery across the nail plate. Choosing the most effective chemical enhancers for the given drug and formulation is highly critical in determining the efficacy of topical therapy of nail diseases. Screening the large pool of enhancers using currently followed diffusion cell experiments would be tedious and expensive. The main objective of this study is to develop TranScreen-N, a high throughput method of screening trans-ungual drug permeation enhancers. It is a rapid microwell plate based method which involves two different treatment procedures; the simultaneous exposure treatment and the sequential exposure treatment. In the present study, several chemicals were evaluated by TranScreen-N and by diffusion studies in the Franz diffusion cell (FDC). Good agreement of in vitro drug delivery data with TranScreen-N data provided validity to the screening technique. In TranScreen-N technique, the enhancers can be grouped according to whether they need to be applied before or simultaneously with drugs (or by either procedures) to enhance the drug delivery across the nail plate. TranScreen-N technique can significantly reduce the cost and duration required to screen trans-ungual drug delivery enhancers. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

  15. A rapid method to authenticate vegetable oils through surface-enhanced Raman scattering

    Science.gov (United States)

    Lv, Ming Yang; Zhang, Xin; Ren, Hai Rui; Liu, Luo; Zhao, Yong Mei; Wang, Zheng; Wu, Zheng Long; Liu, Li Min; Xu, Hai Jun

    2016-03-01

    Vegetable oils are essential in our daily diet. Among various vegetable oils, the major difference lies in the composition of fatty acids, including unsaturated fatty acids (USFA) and saturated fatty acids (SFA). USFA include oleic acid (OA), linoleic acid (LA), and α-linolenic acid (ALA), while SFA are mainly palmitic acid (PA). In this study, the most typical and abundant USFA present with PA in vegetable oils were quantified. More importantly, certain proportional relationships between the integrated intensities of peaks centered at 1656 cm-1 (S1656) in the surface-enhanced Raman scattering spectra of different USFA were confirmed. Therefore, the LA or ALA content could be converted into an equivalent virtual OA content enabling the characterization of the USFA content in vegetable oils using the equivalent total OA content. In combination with the S1656 of pure OA and using peanut, sesame, and soybean oils as examples, the ranges of S1656 corresponding to the National Standards of China were established to allow the rapid authentication of vegetable oils. Gas chromatograph-mass spectrometer analyses verified the accuracy of the method, with relative errors of less than 5%. Moreover, this method can be extended to other detection fields, such as diseases.

  16. New multiplex PCR methods for rapid screening of genetically modified organisms in foods.

    Science.gov (United States)

    Datukishvili, Nelly; Kutateladze, Tamara; Gabriadze, Inga; Bitskinashvili, Kakha; Vishnepolsky, Boris

    2015-01-01

    We present novel multiplex PCR methods for rapid and reliable screening of genetically modified organisms (GMOs). New designed PCR primers targeting four frequently used GMO specific sequences permitted identification of new DNA markers, in particular 141 bp fragment of cauliflower mosaic virus (CaMV) 35S promoter, 224 bp fragment of Agrobacterium tumefaciens nopaline synthase (NOS) terminator, 256 bp fragment of 5-enolppyruvylshikimate-phosphate synthase (epsps) gene and 258 bp fragment of Cry1Ab delta-endotoxin (cry1Ab) gene for GMO screening. The certified reference materials containing Roundup Ready soybean (RRS) and maize MON 810 were applied for the development and optimization of uniplex and multiplex PCR systems. Evaluation of amplification products by agarose gel electrophoresis using negative and positive controls confirmed high specificity and sensitivity at 0.1% GMO for both RRS and MON 810. The fourplex PCR was developed and optimized that allows simultaneous detection of three common transgenic elements, such as: CaMV 35S promoter, NOS terminator, epsps gene together with soybean-specific lectin gene. The triplex PCR developed enables simultaneous identification of transgenic elements, such as: 35S promoter and cry1Ab gene together with maize zein gene. The analysis of different processed foods demonstrated that multiplex PCR methods developed in this study are useful for accurate and fast screening of GM food products.

  17. A simple and rapid method for optical visualization and quantification of bacteria on textiles

    Science.gov (United States)

    Stiefel, Philipp; Schneider, Jana; Amberg, Caroline; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    To prevent bacterial contamination on textiles and the associated undesired effects different biocidal coatings have been investigated and applied. However, due to health and environmental concerns anti-adhesive coatings preventing the binding of bacteria would be favored. To develop such anti-adhesive coatings simple assays for reliable and fast screening are beneficial. Here an easy-to-handle, robust and rapid assay to assess bacteria on textiles utilizing a tetrazolium salt was reported. The assay allowed direct eye visualization of the color change of the textiles containing bacteria, facilitating fast screening. Quantification of the adhered bacteria could be done by generating standard curves which correlate the staining intensity to cell numbers. An additional advantage of the described assay is that with the same detection method anti-adhesive and biocidal effects can be investigated. The method was applied to different coatings, using Pseudomonas aeruginosa and Staphylococcus aureus as model organisms. The detection limit was found to be between 2.5 * 106 and 9.4 * 108 for P. aeruginosa and between 1 * 106 and 3.3 * 108 for S. aureus. The anti-adhesive coating PLUMA was demonstrated to reduce bacterial adhesion without killing them, whereas the biocidal coating TH22-27 caused a clear reduction in the number of viable cells. PMID:28004762

  18. The rapid interphase chromosome assay (RICA implementation: comparison with other PCC methods

    Directory of Open Access Journals (Sweden)

    Sommer Sylwester

    2015-12-01

    Full Text Available A report is presented on the advantages of the rapid interphase chromosome assay (RICA and the difficulties that may be met while implementing this method for application in biological dosimetry. The RICA test can be applied on unstimulated human lymphocytes; this is an advantage in comparison with the dicentric chromosomes or micronucleus tests. In the former two tests, stimulated lymphocytes are examined and hence, 48 h more are needed to obtain cells traversing the cell cycle. Due to the use of unstimulated nondividing cells, higher numbers of cells are available for RICA analysis than for dicentric chromosomes or micronuclei tests. Moreover, the method can be applied after exposure to ionizing radiation doses in excess of 5 Gy. Such doses cause a significant cell cycle delay or result in the loss of G2 phase and mitotic cells because of apoptosis. Therefore, the traditional biodosimetry based on the evaluation of the incidence of damage to chromosomes is very difficult to carry out. This is due to the lack of an adequate number of mitotic cells for analysis. RICA is free of this disadvantage. An automatic microscope can be used to retrieve cell images; automatic image analysis can also be used.

  19. Development of a Rapid and Simple Method to Remove Polyphenols from Plant Extracts

    Directory of Open Access Journals (Sweden)

    Imali Ranatunge

    2017-01-01

    Full Text Available Polyphenols are secondary metabolites of plants, which are responsible for prevention of many diseases. Polyvinylpolypyrrolidone (PVPP has a high affinity towards polyphenols. This method involves the use of PVPP column to remove polyphenols under centrifugal force. Standards of gallic acid, epigallocatechin gallate, vanillin, and tea extracts (Camellia sinensis were used in this study. PVPP powder was packed in a syringe with different quantities. The test samples were layered over the PVPP column and subjected to centrifugation. Supernatant was tested for the total phenol content. The presence of phenolic compounds and caffeine was screened by HPLC and measuring the absorbance at 280. The antioxidant capacity of standards and tea extracts was compared with the polyphenol removed fractions using DPPH scavenging assay. No polyphenols were found in polyphenolic standards or tea extracts after PVPP treatment. The method described in the present study to remove polyphenols is simple, inexpensive, rapid, and efficient and can be employed to investigate the contribution of polyphenols present in natural products to their biological activity.

  20. A Rapid and Low-Cost Nonlithographic Method to Fabricate Biomedical Microdevices for Blood Flow Analysis

    Directory of Open Access Journals (Sweden)

    Elmano Pinto

    2014-12-01

    Full Text Available Microfluidic devices are electrical/mechanical systems that offer the ability to work with minimal sample volumes, short reactions times, and have the possibility to perform massive parallel operations. An important application of microfluidics is blood rheology in microdevices, which has played a key role in recent developments of lab-on-chip devices for blood sampling and analysis. The most popular and traditional method to fabricate these types of devices is the polydimethylsiloxane (PDMS soft lithography technique, which requires molds, usually produced by photolithography. Although the research results are extremely encouraging, the high costs and time involved in the production of molds by photolithography is currently slowing down the development cycle of these types of devices. Here we present a simple, rapid, and low-cost nonlithographic technique to create microfluidic systems for biomedical applications. The results demonstrate the ability of the proposed method to perform cell free layer (CFL measurements and the formation of microbubbles in continuous blood flow.

  1. A rapid and sensitive spectrophotometric method for the determination of benzoyl peroxide in wheat flour samples

    Directory of Open Access Journals (Sweden)

    Kraingkrai Ponhong

    2015-12-01

    Full Text Available A simple, rapid, and sensitive spectrophotometric method for the determination of benzoyl peroxide (BPO in wheat flour samples was developed. The detection principle is based on BPO reacted with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS to obtain a blue-green colored product that was detected at 415 nm by spectrophotometry. The effect of factors influencing the color reaction was investigated. Under the selected conditions, the linear range for quantification of BPO was observed between 0.2–1.0 mg L−1 with r2 = 0.998. The limit of detection (LOD was 0.025 mg L−1. The developed method obtained superior precision (relative standard deviation < 2% using 11 repeatability at 0.2 mg L−1, 0.6 mg L−1, and 0.8 mg L−1. The proposed methodology was successfully applied to determine BPO in wheat flour samples.

  2. New multiplex PCR methods for rapid screening of genetically modified organisms in foods

    Directory of Open Access Journals (Sweden)

    Nelly eDatukishvili

    2015-07-01

    Full Text Available We present novel multiplex PCR methods for rapid and reliable screening of genetically modified organisms (GMOs. New designed PCR primers targeting four frequently used GMO specific sequences permitted identification of new DNA markers, in particular 141 bp fragment of cauliflower mosaic virus (CaMV 35S promoter, 224 bp fragment of Agrobacterium tumefaciens nopaline synthase (NOS terminator, 256 bp fragment of 5-enolppyruvylshikimate-phosphate synthase (epsps gene and 258 bp fragment of Cry1Ab delta-endotoxin (cry1Ab gene for GMO screening. The certified reference materials containing Roundup Ready soybean (RRS and maize MON 810 were applied for the development and optimization of uniplex and multiplex PCR systems. Evaluation of amplification products by agarose gel electrophoresis using negative and positive controls confirmed high specificity and sensitivity at 0.1% GMO for both RRS and MON 810. The fourplex PCR was developed and optimized that allows simultaneous detection of three common transgenic elements, such as: CaMV 35S promoter, NOS terminator, epsps gene together with soybean-specific lectin gene. The triplex PCR developed enables simultaneous identification of transgenic elements, such as: 35S promoter and cry1Ab gene together with maize zein gene. The analysis of different processed foods demonstrated that multiplex PCR methods developed in this study are useful for accurate and fast screening of GM food products.

  3. Regional distribution of methionine adenosyltransferase in rat brain as measured by a rapid radiochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Hiemke, C.; Ghraf, R.

    1981-09-01

    The distribution of methionine adenosyltransferase (MAT) in the CNS of the rat was studied by use of a rapid, sensitive and specific radiochemical method. The S-adenosyl-(methyl-/sup 14/C)L-methionine ((/sup 14/C)SAM) generated by adenosyl transfer from ATP to (methyl-/sup 14/C)L-methionine is quantitated by use of a SAM-consuming transmethylation reaction. Catechol O-methyltransferase (COMT), prepared from rat liver, transfers the methyl-/sup 14/C group of SAM to 3,4-dihydroxybenzoic acid. The /sup 14/C-labelled methylation products, vanillic acid and isovanillic acid, are separated from unreacted methionine by solvent extraction and quantitated by liquid scintillation counting. Compared to other methods of MAT determination, which include separation of generated SAM from methionine by ion-exchange chromatography, the assay described exhibited the same high degree of specificity and sensitivity but proved to be less time consuming. MAT activity was found to be uniformly distributed between various brain regions and the pituitary gland of adult male rats. In the pineal gland the enzyme activity is about tenfold higher.

  4. Method and apparatus using selected superparamagnetic labels for rapid quantification of immunochromatographic tests

    Directory of Open Access Journals (Sweden)

    Mika PA Laitinen

    2009-04-01

    Full Text Available Mika PA Laitinen1, Jari Salmela2, Leona Gilbert1, Risto Kaivola1, Topi Tikkala2, Christian Oker-Blom1, Jukka Pekola3, Matti Vuento11Department of Biological and Environmental Science; 2Department of Physics, University of Jyväskylä, Jyväskylä, Finland; 3Low Temperature Laboratory, Helsinki University of Technology, Helsinki, FinlandAbstract: A rapid method and instrumentation for quantification of immunochromatographic tests (ICT are described. The principle and performance of the method was demonstrated by measuring the levels of human chorionic gonadotropin (hCG present in urine. The test format was a sandwich assay using two distinct monoclonal antibodies directed against hCG. The first anti-hCG antibody was labeled with superparamagnetic particles whereas the second was immobilized as a narrow detection zone on a porous membrane. The human urine sample was mixed with superparamagnetic particles coated with the first anti-hCG antibody, and the mixture was allowed to migrate past the detection zone containing the second anti-hCG antibody. Capillary forces facilitated migration of the immune complexes along the porous membrane. The amount of superparamagnetic particle-labelled monoclonal anti-hCG bound to the detection zone was directly proportional to the amount of hCG present in the sample as detected by measuring magnetization in the detector coil. The method had a practical detection limit of 20 U/l (54 nM of hCG per 5 μl of human urine and a linear range of three decades from 20 U/l to 10 000 U/l. In addition, the analysis was completed within less than 10 minutes. Thus, the test format should be suitable for fast detection and monitoring of a large variety of clinically important parameters and analytes.Keywords: affinity, biosensor, hCG, immunochromatography, magnetization, superparamagnetic

  5. Rapid methods to assess sanitizing efficacy of benzalkonium chloride to Listeria monocytogenes biofilms.

    Science.gov (United States)

    Romanova, Nadya A; Gawande, Purushottam V; Brovko, Lubov Y; Griffiths, Mansel W

    2007-12-01

    Different methods were used to investigate biofilm growth including crystal violet staining, ATP bioluminescence and total viable count. Seven strains of Listeria monocytogenes and 8 of their derivative strains were screened for their capacity to form biofilms. Both adaptation to benzalkonium chloride (BC) and curing of plasmids did not significantly affect biofilm-forming ability. The strains of L. monocytogenes belonging to serotype 1 formed biofilms significantly better as compared to serotype 4 (P=0.0003). To estimate the efficacy of BC for biofilm elimination the best and the poorest biofilm-formers were used (C719 and LJH 381). It was observed that, L. monocytogenes strain C719 in biofilms is at least 1000 times more resistant to BC than in planktonic form. Cells present in biofilms were shown to recover and grow after BC treatment thus providing a source of recontamination. It was shown that ATP bioluminescence provides good correlation with bacterial counts of L. monocytogenes in biofilms. Staining with crystal violet, on the contrary, did not correlate with bacterial growth in biofilms in the presence of high concentrations of BC but provided information on the concentration of bacterial cells, both live and dead, attached to the surface. ATP bioluminescence was found to be a reliable method for rapid estimation of the efficacy of sanitizers for biofilm disinfection. Crystal violet staining, on the other hand, was shown to be a suitable method to monitor removal of biofilms. Our investigation showed that for Listeria biofilms concentrations of BC higher then 10 mg/ml should be applied for at least 30 min to kill almost all the live cells in biofilms. However, this concentration was still not enough to remove biofilms from the surface of plastic.

  6. Development of a rapid, one-step screening method for the isolation of presumptive proteolytic enterococci.

    Science.gov (United States)

    Graham, Ken; Rea, Rosemary; Simpson, Paul; Stack, Helena

    2017-01-01

    Enterococci show higher proteolytic activities than other lactic acid bacteria and thus have received considerable attention in scientific literature in recent years. Proteolytic enzymes of enterococci have warranted the use of some species as starter, adjuncts or protective cultures and as probiotics, while in some strains they have also been linked with virulence. Consequently, the isolation and identification of proteolytic enterococci is becoming of increasing interest and importance. However, current screening methods for proteolytic enterococci can be time consuming, requiring a two-step procedure which may take up to 96h. This study describes a method, utilising Kanamycin Skim Milk Aesculin Azide (KSMEA) agar, for the isolation of proteolytic enterococci in one-step, thereby significantly reducing screening time. KSMEA combines the selective properties of Kanamycin Aesculin Azide Agar (KAA) with skim milk powder for the detection of proteolytic enterococci. Enterococci produced colonies with a black halo on KSMEA which were accompanied by a zone of clearing in the media when enterococci were proteolytic. KSMEA medium retained the selectivity of KAA, while proteolytic enterococci were easily distinguished from non-proteolytic enterococci when two known strains were propagated on KSMEA. KSMEA also proved effective at isolating and detecting enterococci in raw milk, faeces and soil. Isolates recovered from the screen were confirmed as enterococci using genus-specific primers. Proteolytic enterococci were present in the raw milk sample only and were easily distinguishable from non-proteolytic enterococci and other microorganisms. Therefore, KSMEA provides a rapid, one-step screening method for the isolation of presumptive proteolytic enterococci. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Discovering the enzyme mimetic activity of metal-organic framework (MOF) for label-free and colorimetric sensing of biomolecules.

    Science.gov (United States)

    Wang, Ying; Zhu, Yingjing; Binyam, Atsebeha; Liu, Misha; Wu, Yinan; Li, Fengting

    2016-12-15

    A label-free sensing strategy based on the enzyme-mimicking activity of MOF was demonstrated for colorimetric detection of biomolecules. Firstly obvious blue color was observed due to the high efficiency of peroxidase-like catalytic activity of Fe-MIL-88A (an ion-based MOF material) toward 3,3',5,5'-tetramethylbenzidine (TMB). Then in the presence of target biomolecule and corresponding aptamer, the mimetic activity of Fe-MIL-88A can be strongly inhibited and used directly to realize the colorimetric detection. On the basis of the interesting findings, we designed a straightforward, label-free and sensitive colorimetric method for biomolecule detection by using the enzyme mimetic property of MOF coupling with molecular recognition element. Compared with the existed publications, our work breaks the routine way by setting up an inorganic-organic MOF-aptamer hybrid platform for colorimetric determination of biomolecules, expanding the targets scope from H2O2 or glucose to biomolecules. As a proof of concept, thrombin and thrombin aptamer was used as a model analyte. The limit of detection of 10nM can be achieved with naked eyes and ultrahigh selectivity of thrombin toward numerous interfering substances with 10-fold concentration was demonstrated significantly. Of note, the method was further applied for the detection of thrombin in human serum samples, showing the results in agreement with those values obtained in an immobilization buffer by the colorimetric method. This inorganic-organic MOF-aptamer sensing strategy may in principle be universally applicable for the detection of a range of environmental or biomedical molecules of interests. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. ``Red-to-blue'' colorimetric detection of cysteine via anti-etching of silver nanoprisms

    Science.gov (United States)

    Li, Yonglong; Li, Zihou; Gao, Yuexia; Gong, An; Zhang, Yujie; Hosmane, Narayan S.; Shen, Zheyu; Wu, Aiguo

    2014-08-01

    The reported strategies for cysteine (Cys) colorimetric detection based on noble metal nanomaterials include triggering aggregation, etching or fluorescence quenching of nanomaterials by Cys. In this study, we propose a new strategy for Cys colorimetric detection, i.e. anti-etching of silver nanoprisms (AgNPRs). In the absence of Cys, iodide ions (I-) could etch the corners and edges of AgNPRs and induce the morphology transition from nanoprism to nanodisk, which results in color change of the AgNPR dispersion from blue to red. In its presence, however, Cys can prevent the AgNPRs from I- attack. In that case, the color of the AgNPR dispersion containing I- and Cys remains blue. The mechanism is confirmed by using UV-vis spectra, TEM, DLS, Raman spectra and XPS spectra. According to the sensing effect of the Cys detection system, the concentration of I- incubated with AgNPRs, incubation time of AgNPRs and I-, and pH of AgNPR dispersions are optimized to 5.0 μM, 10 min, and pH 6.2, respectively. Under the optimized conditions, the proposed Cys detection system has excellent selectivity and high sensitivity. The limit of detection (LOD) of our Cys detection system is 25 nM by the naked eye, which is much better than the reported lowest LOD by eye-vision (100 nM), and 10 nM by UV-vis spectroscopy. The results of Cys detection in rabbit urine or plasma samples reinforce that our Cys detection system is applicable for rapid colorimetric detection of Cys in real body fluid samples.The reported strategies for cysteine (Cys) colorimetric detection based on noble metal nanomaterials include triggering aggregation, etching or fluorescence quenching of nanomaterials by Cys. In this study, we propose a new strategy for Cys colorimetric detection, i.e. anti-etching of silver nanoprisms (AgNPRs). In the absence of Cys, iodide ions (I-) could etch the corners and edges of AgNPRs and induce the morphology transition from nanoprism to nanodisk, which results in color change of the

  9. Improvements in fast-neutron spectroscopy methods (1961); Amelioration des methodes de spectrometrie des neutrons rapides (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Cambou, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-02-15

    This research aimed at improving fast-neutron electronic detectors based on n-p elastic scattering. The first part concerns proportional counters; careful constructional methods have made it possible to plot mono-energetic neutron spectra in the range 700 keV - 3 MeV with a resolution of 7 per cent. The second part concerns scintillation counters: an organic scintillator and an inorganic scintillator covered with a thin layer of a scattering agent. An exact study of the types of scintillation has made it possible to develop efficient discriminator circuits. Different neutron spectra plotted in the presence of a strong gamma background are presented. The last part deals with the development of form discrimination methods for the study, in the actual beam, of the elastic scattering of 14.58 MeV electrons. With hydrogen, the distribution f ({phi}) of the recoil protons is f({phi}) = 1 + 0.034 cos {phi} + 0.042 cos{sup 2} {phi}. With tritium the scattering is strongly anisotropic; the curve representing the variation of the differential cross-section for the elastic scattering in the centre of mass system is obtained with a target containing 1 cm{sup 3} of tritium. (author) [French] Le travail a porte sur l'amelioration des detecteurs electroniques de neutrons rapides bases sur la diffusion elastique n-p. La premiere partie est relative aux compteurs proportionnels; des methodes soignees de fabrication ont permis des traces de spectres de neutrons monoenergetiques dans le domaine 700 keV - 3 MeV avec une resolution de 7 pour cent. La deuxieme partie est relative au compteur a scintillations; scintillateur organique et scintillateur mineral recouvert d'un diffuseur mince. Une etude precise des formes de scintillations a permis la mise au point de circuits discriminateurs efficaces. Differents spectres de neutrons traces en presence d'un fond gamma intense sont presentes. La derniere partie est relative a la mise en oeuvre des methodes de discrimination de

  10. Development of a rapid method for the quantitative determination of deoxynivalenol using Quenchbody

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinari, Tomoya [Division of Microbiology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Ohashi, Hiroyuki; Abe, Ryoji; Kaigome, Rena [Biomedical Division, Ushio Inc., 1-12 Minamiwatarida-cho, Kawasaki-ku, Kawasaki 210-0855 (Japan); Ohkawa, Hideo [Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Sugita-Konishi, Yoshiko, E-mail: y-konishi@azabu-u.ac.jp [Department of Food and Life Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201 (Japan)

    2015-08-12

    Quenchbody (Q-body) is a novel fluorescent biosensor based on the antigen-dependent removal of a quenching effect on a fluorophore attached to antibody domains. In order to develop a method using Q-body for the quantitative determination of deoxynivalenol (DON), a trichothecene mycotoxin produced by some Fusarium species, anti-DON Q-body was synthesized from the sequence information of a monoclonal antibody specific to DON. When the purified anti-DON Q-body was mixed with DON, a dose-dependent increase in the fluorescence intensity was observed and the detection range was between 0.0003 and 3 mg L{sup −1}. The coefficients of variation were 7.9% at 0.003 mg L{sup −1}, 5.0% at 0.03 mg L{sup −1} and 13.7% at 0.3 mg L{sup −1}, respectively. The limit of detection was 0.006 mg L{sup −1} for DON in wheat. The Q-body showed an antigen-dependent fluorescence enhancement even in the presence of wheat extracts. To validate the analytical method using Q-body, a spike-and-recovery experiment was performed using four spiked wheat samples. The recoveries were in the range of 94.9–100.2%. The concentrations of DON in twenty-one naturally contaminated wheat samples were quantitated by the Q-body method, LC-MS/MS and an immunochromatographic assay kit. The LC-MS/MS analysis showed that the levels of DON contamination in the samples were between 0.001 and 2.68 mg kg{sup −1}. The concentrations of DON quantitated by LC-MS/MS were more strongly correlated with those using the Q-body method (R{sup 2} = 0.9760) than the immunochromatographic assay kit (R{sup 2} = 0.8824). These data indicate that the Q-body system for the determination of DON in wheat samples was successfully developed and Q-body is expected to have a range of applications in the field of food safety. - Highlights: • A rapid method for quantitation of DON using Q-body has been developed. • A recovery test using the anti-DON Q-body was performed. • The concentrations of DON in wheat

  11. A rapid method for detection of five known mutations associated with aminoglycoside-induced deafness

    Directory of Open Access Journals (Sweden)

    Greinwald John H

    2009-01-01

    Full Text Available Abstract Background South Africa has one of the highest incidences of multidrug-resistant tuberculosis (MDR-TB in the world. Concomitantly, aminoglycosides are commonly used in this country as a treatment against MDR-TB. To date, at least five mutations are known to confer susceptibility to aminoglycoside-induced hearing loss. The aim of the present study was to develop a rapid screening method to determine whether these mutations are present in the South African population. Methods A multiplex method using the SNaPshot technique was used to screen for five mutations in the MT-RNR1 gene: A1555G, C1494T, T1095C, 961delT+C(n and A827G. A total of 204 South African control samples, comprising 98 Mixed ancestry and 106 Black individuals were screened for the presence of the five mutations. Results A robust, cost-effective method was developed that detected the presence of all five sequence variants simultaneously. In this pilot study, the A1555G mutation was identified at a frequency of 0.9% in the Black control samples. The 961delT+C(n variant was present in 6.6% of the Black controls and 2% of the Mixed ancestry controls. The T1095C, C1494T and A827G variants were not identified in any of the study participants. Conclusion The frequency of 0.9% for the A1555G mutation in the Black population in South Africa is of concern given the high incidence of MDR-TB in this particular ethnic group. Future larger studies are warranted to determine the true frequencies of the aminoglycoside deafness mutations in the general South African population. The high frequencies of the 961delT+C(n variant observed in the controls suggest that this change is a common non-pathogenic polymorphism. This genetic method facilitates the identification of individuals at high risk of developing hearing loss prior to the start of aminoglycoside therapy. This is important in a low-resource country like South Africa where, despite their adverse side-effects, aminoglycosides will

  12. Optimized enzymatic colorimetric assay for determination of hydrogen peroxide (H2O2) scavenging activity of plant extracts.

    Science.gov (United States)

    Fernando, Chamira Dilanka; Soysa, Preethi

    2015-01-01

    The classical method to determine hydrogen peroxide (H2O2) scavenging activity of plant extracts is evaluated by measuring the disappearance of H2O2 at a wavelength of 230 nm. Since this method suffers from the interference of phenolics having strong absorption in the UV region, a simple and rapid colorimetric assay was developed where plant extracts are introduced to H2O2, phenol and 4-aminoantipyrine reaction system in the presence of horseradish peroxidase (HRP). This reaction yields a quinoneimine chromogen which can be measured at 504 nm. Decrease in the colour intensity reflects the H2O2 scavenged by the plant material. •Optimum conditions determined for this assay were 30 min reaction time, 37 °C, pH 7, enzyme concentration of 1 U/ml and H2O2 concentration of 0.7 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 136 μM and 411 μM, respectively.•Half maximal effective concentration required to scavenge 50% of H2O2 in the system (EC50 value) calculated for several plant extracts and standard antioxidants resulted in coefficient of variance (CV%) of the EC50 values less than 3.0% and correlation coefficient values (R (2)) > 0.95 for all dose response curves obtained.•This method is convenient and very precise which is suitable for the rapid quantification of H2O2 scavenging ability of standard antioxidants and natural antioxidants present in plant extracts.

  13. A BTT-Based Colorimetric Dual Sensor for Hg(II and Selected Anions with Molecular Logic Operations

    Directory of Open Access Journals (Sweden)

    Veikko Uahengo

    2016-01-01

    Full Text Available A benzotrithiophenes (BTT based colorimetric sensor (2 was synthesized via a simple one-step reaction process, and its recognition properties towards several biologically important anions and cations were investigated by naked eye observation and spectroscopic methods of UV-vis and 1H NMR analysis in DMSO. The molar addition of anions such as F−, AcO−, and H2PO4- induced a marked red shift of the charge transfer band (Δλ=94 nm, from 440 nm to 534 nm concomitant with a clearly visible “naked eye” detectable colorimetric activities (from orange to pink. However, the molar addition of H2PO4- did not induce significant spectral changes, compared to F− and AcO−. Furthermore, the molar addition of Hg2+ to 2 resulted in hypochromic shift at 440 nm and the eventual disappearance of a low energy band at 534 nm, concomitant with the colorimetric activities (from orange to yellow. Moreover, both spectral and color changes induced by the addition of anions (F− and AcO− were all reversible by the molar addition of metal cations of 3d5–10. The reversibility properties triggered the logic operation studies, and, subsequently, the complementary IMP/INH logic functions based on color and spectral switching (ON/OFF were confirmed. Conclusively, 2 can thus be utilized as a colorimetric molecular switch modulated by AcO−/MII.

  14. UV-vis spectroscopy and colorimetric models for detecting anthocyanin-metal complexes in plants: An overview of in vitro and in vivo techniques.

    Science.gov (United States)

    Fedenko, Volodymyr S; Shemet, Sergiy A; Landi, Marco

    2017-05-01

    Although anthocyanin (ACN) biosynthesis is one of the best studied pathways of secondary metabolism in plants, the possible physiological and ecological role(s) of these pigments continue to intrigue scientists. Like other dihydroxy B-ring substituted flavonoids, ACNs have an ability to bind metal and metalloid ions, a property that has been exploited for a variety of purposes. For example, the metal binding ability may be used to stabilize ACNs from plant food sources, or to modify their colors for using them as food colorants. The complexation of metals with cyanidin derivatives can also be used as a simple, sensitive, cheap, and rapid method for determination concentrations of several metals in biological and environmental samples using UV-vis spectroscopy. Far less information is available on the ecological significance of ACN-metal complexes in plant-environment interactions. Metalloanthocyanins (protocyanin, nemophilin, commelinin, protodelphin, cyanosalvianin) are involved in the copigmentation phenomenon that leads to blue-pigmented petals, which may facilitate specific plant-pollinator interactions. ACN-metal formation and compartmentation into the vacuole has also been proposed to be part of an orchestrated detoxification mechanism in plants which experience metal/metalloid excess. However, investigations into ACN-metal interactions in plant biology may be limited because of the complexity of the analytical techniques required. To address this concern, here we describe simple methods for the detection of ACN-metal both in vitro and in vivo using UV-vis spectroscopy and colorimetric models. In particular, the use of UV-vis spectra, difference absorption spectra, and colorimetry techniques will be described for in vitro determination of ACN-metal features, whereas reflectance spectroscopy and colorimetric parameters related to CIE L(*)a(*)b(*) and CIE XYZ systems will be detailed for in vivo analyses. In this way, we hope to make this high-informative tool

  15. Rapid Visual Tests: Fast and Reliable Detection of Ochratoxin A

    Directory of Open Access Journals (Sweden)

    Miguel Lopez-Ferber

    2010-08-01

    Full Text Available This paper reviews the early detection strategies that have been employed for the rapid monitoring of ochratoxin A (OTA contamination of food. OTA, a mycotoxin mainly produced by some Aspergillus and Penicillium species, is found in cereals, coffee, wine, pork and grapes. To minimize the entry of this mycotoxin into the food chain, rapid diagnostic tools are required. To this end, the potential use of lateral flow devices has also been developed. In this study, we analyze the robustness of test strips using published methods for colorimetric detection. Different test formats are discussed, and challenges in the development of lateral flow devices for on-site determination of OTA, with requirements such as robustness, speed, and cost-effectiveness, are discussed.

  16. A Rapid and Simple TLC-Densitometric Method for Assay of Clobetasol Propionate in Topical Solution.

    Science.gov (United States)

    Dolowy, Malgorzata; Kozik, Violetta; Bak, Andrzej; Jampilek, Josef; Barbusinski, Krzysztof; Thomas, Maciej; Pyka-Pajak, Alina

    2017-11-03

    A rapid, simple to use and low-cost thin-layer chromatographic procedure in normal phase system with densitometric detection at 246 nm was carefully validated according to the International Conference on Harmonisation (ICH) guidelines for assay of clobetasol propionate in topical solution containing clobetasol propionate in quantity 0.50 mg/mL. The adopted thin-layer chromatographic (TLC)-densitometric procedure could effectively separate clobetasol propionate from its related compound, namely clobetasol. It is linear for clobetasol propionate in the range of 0.188 ÷ 5 µg/spot. The limit of detection (LOD) and limit of quantification (LOQ) value is 0.061 and 0.186 µg/spot, respectively. Accuracy of proposed procedure was evaluated by recovery test. The mean recovery of studied clobetasol propionate ranges from 98.7 to 101.0%. The coefficient of variation (CV, %) obtained during intra-day and inter-day studies, which was less than 2% (0.40 ÷ 1.17%), confirms the precision of described method. The assay value of clobetasol propionate is consistent with the pharmacopoeial requirements. In conclusion, it can be suitable as a simple and economic procedure for routine quality control laboratories of clobetasol propionate in topical solution.

  17. Hydrodynamic Voltammetry as a Rapid and Simple Method for Evaluating Soil Enzyme Activities

    Directory of Open Access Journals (Sweden)

    Kazuto Sazawa

    2015-03-01

    Full Text Available Soil enzymes play essential roles in catalyzing reactions necessary for nutrient cycling in the biosphere. They are also sensitive indicators of ecosystem stress, therefore their evaluation is very important in assessing soil health and quality. The standard soil enzyme assay method based on spectroscopic detection is a complicated operation that requires the removal of soil particles. The purpose of this study was to develop a new soil enzyme assay based on hydrodynamic electrochemical detection using a rotating disk electrode in a microliter droplet. The activities of enzymes were determined by measuring the electrochemical oxidation of p-aminophenol (PAP, following the enzymatic conversion of substrate-conjugated PAP. The calibration curves of β-galactosidase (β-gal, β-glucosidase (β-glu and acid phosphatase (AcP showed good linear correlation after being spiked in soils using chronoamperometry. We also performed electrochemical detection using real soils. Hydrodynamic chronoamperometry can be used to assess the AcP in soils, with a detection time of only 90 s. Linear sweep voltammetry was used to measure the amount of PAP released from β-gal and β-glu by enzymatic reaction after 60 min. For the assessment of soil enzymes, the results of hydrodynamic voltammetry assay compared favorably to those using a standard assay procedure, but this new procedure is more user-friendly, rapid and simple.

  18. An assessment of various blood collection and transfer methods used for malaria rapid diagnostic tests

    Directory of Open Access Journals (Sweden)

    Baik Fred

    2007-11-01

    Full Text Available Abstract Background Four blood collection and transfer devices commonly used for malaria rapid diagnostic tests (RDTs were assessed for their consistency, accuracy and ease of use in the hands of laboratory technicians and village health workers. Methods Laboratory technicians and village health workers collected blood from a finger prick using each device in random order, and deposited the blood either on filter paper or into a suitable casette-type RDT. Consistency and accuracy of volume delivered was determined by comparing the measurements of the resulting blood spots/heights with the measurements of laboratory-prepared pipetted standard volumes. The effect of varying blood volumes on RDT sensitivity and ease of use was also observed. Results There was high variability in blood volume collected by the devices, with the straw and the loop, the most preferred devices, usually transferring volumes greater than intended, while the glass capillary tube and the plastic pipette transferring less volume than intended or none at all. Varying the blood volume delivered to RDTs indicated that this variation is critical to RDT sensitivity only when the transferred volume is very low. Conclusion None of the blood transfer devices assessed performed consistently well. Adequate training on their use is clearly necessary, with more development efforts for improved designs to be used by remote health workers, in mind.

  19. Rapid characterization of transgenic and non-transgenic soybean oils by chemometric methods using NIR spectroscopy

    Science.gov (United States)

    Luna, Aderval S.; da Silva, Arnaldo P.; Pinho, Jéssica S. A.; Ferré, Joan; Boqué, Ricard

    Near infrared (NIR) spectroscopy and multivariate classification were applied to discriminate soybean oil samples into non-transgenic and transgenic. Principal Component Analysis (PCA) was applied to extract relevant features from the spectral data and to remove the anomalous samples. The best results were obtained when with Support Vectors Machine-Discriminant Analysis (SVM-DA) and Partial Least Squares-Discriminant Analysis (PLS-DA) after mean centering plus multiplicative scatter correction. For SVM-DA the percentage of successful classification was 100% for the training group and 100% and 90% in validation group for non transgenic and transgenic soybean oil samples respectively. For PLS-DA the percentage of successful classification was 95% and 100% in training group for non transgenic and transgenic soybean oil samples respectively and 100% and 80% in validation group for non transgenic and transgenic respectively. The results demonstrate that NIR spectroscopy can provide a rapid, nondestructive and reliable method to distinguish non-transgenic and transgenic soybean oils.

  20. New 16-plex PCR method for rapid detection of diarrheagenic Escherichia coli directly from stool samples.

    Science.gov (United States)

    Antikainen, J; Tarkka, E; Haukka, K; Siitonen, A; Vaara, M; Kirveskari, J

    2009-08-01

    A rapid 16-plex polymerase chain reaction (PCR) suitable for routine diagnostics of diarrheagenic Escherichia coli (EHEC, EIEC, EAEC, ETEC, and EPEC) was developed, validated with control strains, and tested with 250 diarrhoeal stool samples. The specificity was 100% when tested with 289 control bacterial strains, and the analytical sensitivity of automated DNA extraction directly from stool samples was made by boiling the bacterial culture (10(4)-10(5) colony forming units/ml). The assay design starting directly from extraction of stool DNA allowed same day analysis without compromising sensitivity and specificity, which makes it superior compared to PCR after culturing the bacteria. The 16-plex PCR method demonstrated high prevalence of diarrheagenic E. coli in stool samples of patients returning from abroad (39.0%) in contrast to the patients with no travel history (8.7%; p < 0.001). The high prevalence of diarrheagenic E. coli suggests that their screening should be part of normal diarrhoea diagnostics, at least in the leading diagnostic laboratories.

  1. A Simple and Rapid Method for Preparing a Cell-Free Bacterial Lysate for Protein Synthesis.

    Directory of Open Access Journals (Sweden)

    Nitzan Krinsky

    Full Text Available Cell-free protein synthesis (CFPS systems are important laboratory tools that are used for various synthetic biology applications. Here, we present a simple and inexpensive laboratory-scale method for preparing a CFPS system from E. coli. The procedure uses basic lab equipment, a minimal set of reagents, and requires less than one hour to process the bacterial cell mass into a functional S30-T7 extract. BL21(DE3 and MRE600 E. coli strains were used to prepare the S30-T7 extract. The CFPS system was used to produce a set of fluorescent and therapeutic proteins of different molecular weights (up to 66 kDa. This system was able to produce 40-150 μg-protein/ml, with variations depending on the plasmid type, expressed protein and E. coli strain. Interestingly, the BL21-based CFPS exhibited stability and increased activity at 40 and 45°C. To the best of our knowledge, this is the most rapid and affordable lab-scale protocol for preparing a cell-free protein synthesis system, with high thermal stability and efficacy in producing therapeutic proteins.

  2. HPLC method for rapidly following biodiesel fuel transesterification reaction progress using a core-shell column

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Samuel J.; Ott, Lisa S. [California State University, Chico, CA (United States)

    2012-07-15

    There are a wide and growing variety of feedstocks for biodiesel fuel. Most commonly, these feedstocks contain triglycerides which are transesterified into the fatty acid alkyl esters (FAAEs) which comprise biodiesel fuel. While the tranesterification reaction itself is simple, monitoring the reaction progress and reaction products is not. Gas chromatography-mass spectrometry is useful for assessing the FAAE products, but does not directly address either the tri-, di-, or monoglycerides present from incomplete transesterification or the free fatty acids which may also be present. Analysis of the biodiesel reaction mixture is complicated by the solubility and physical property differences among the components of the tranesterification reaction mixture. In this contribution, we present a simple, rapid HPLC method which allows for monitoring all of the main components in a biodiesel fuel transesterification reaction, with specific emphasis on the ability to monitor the reaction as a function of time. The utilization of a relatively new, core-shell stationary phase for the HPLC column allows for efficient separation of peaks with short elution times, saving both time and solvent. (orig.)

  3. Lock-in thermography as a rapid and reproducible thermal characterization method for magnetic nanoparticles

    Science.gov (United States)

    Lemal, Philipp; Geers, Christoph; Monnier, Christophe A.; Crippa, Federica; Daum, Leopold; Urban, Dominic A.; Rothen-Rutishauser, Barbara; Bonmarin, Mathias; Petri-Fink, Alke; Moore, Thomas L.

    2017-04-01

    Lock-in thermography (LIT) is a sensitive imaging technique generally used in engineering and materials science (e.g. detecting defects in composite materials). However, it has recently been expanded for investigating the heating power of nanomaterials, such as superparamagnetic iron oxide nanoparticles (SPIONs). Here we implement LIT as a rapid and reproducible method that can evaluate the heating potential of various sizes of SPIONs under an alternating magnetic field (AMF), as well as the limits of detection for each particle size. SPIONs were synthesized via thermal decomposition and stabilized in water via a ligand transfer process. Thermographic measurements of SPIONs were made by stimulating particles of varying sizes and increasing concentrations under an AMF. Furthermore, a commercially available SPION sample was included as an external reference. While the size dependent heating efficiency of SPIONs has been previously described, our objective was to probe the sensitivity limits of LIT. For certain size regimes it was possible to detect signals at concentrations as low as 0.1 mg Fe/mL. Measuring at different concentrations enabled a linear regression analysis and extrapolation of the limit of detection for different size nanoparticles.

  4. A method for the rapid detection and identification of halo blight pathogen on common bean

    Directory of Open Access Journals (Sweden)

    Popović Tatjana

    2014-01-01

    Full Text Available A diagnostic method based on nested-PCR, followed by ELISA and conventional bacteriology tests, for the rapid and reliable detection of halo blight pathogen Pseudomonas savastanoi pv. phaseolicola (Psp collected from infected bean leaves and seeds is described. Psp formed white, small and flat colonies on nutrient agar medium, creamy white, flat and circular on Milk-Tween agar medium and light yellow, convex and shiny on modified sucrose peptone agar medium. Eighteen Gram-negative, catalase-positive and oxidase-negative strains were subjected to nested PCR with primers P 5.1/P 3.1 and P 5.2/P 3.2, which directed the amplification of the 450 bp target DNA fragment in all tested strains. According to the results of DAS- and PTA-ELISA with respect to reactivity to specific antibodies, all analyzed strains belonged to Psp bacterium. Pathogenicity was tested on bean pods and cotyledon leaves, on which greasy spots were formed. Psp did not cause hypersensitive reaction on the leaves of tobacco and geranium. Strains produced levan, fluorescent pigment, oxidative metabolism of glucose, did not reduce nitrate, did not produce indole and H2S, did not hydrolyze starch, gelatin and esculin; they produced acid from glucose, mannose, sucrose and glycerol, and did not produce acid from maltose, starch, esculin, dulcite, sorbitol, inositol and erythritol.

  5. A universal probe design for colorimetric detection of single-nucleotide variation with visible readout and high specificity.

    Science.gov (United States)

    Chen, Xueping; Zhou, Dandan; Shen, Huawei; Chen, Hui; Feng, Wenli; Xie, Guoming

    2016-02-02

    Single-nucleotide variation (SNV) is a crucial biomarker for drug resistance-related detection in cancer and bacterial infection. However, the unintended binding of DNA probes limits the specificity of SNV detection, and the need for redesigned sequences compromise the universality of SNV assay. Herein, we demonstrated a universal and low-cost assay for the colorimetric discrimination of drug-resistance related point mutation. By the use of a universal DNA probe and a split G-quadruplex, the signal could be recognized by naked eye at room temperature. The DNA probe was used as a signal reporter which not only improved the universality, but also enabled high specificity of probe hybridization. This assay was successfully applied in the detection of cancer-related SNV in the epidermal growth factor receptor (EGFR) gene, kirsten rat sarcoma viral oncogene homologue (KRAS), and tuberculosis drug-resistance related point mutation in RNA polymerase beta subunit gene (rpoB) with high specificity and visible readout. This method was simple, rapid, high-throughput and effective, which was suitable for point-of-care applications.

  6. Colorimetric detection of Cd{sup 2+} using 1-amino-2-naphthol-4-sulfonic acid functionalized silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pengcheng; Liu, Bowen; Jin, Weiwei; Wu, Fangying, E-mail: fywu@ncu.edu.cn; Wan, Yiqun [Nanchang University, College of Chemistry (China)

    2016-11-15

    A colorimetric assay has been developed for facile, rapid, and sensitive detection of Cd{sup 2+} using 1-amino-2-naphthol-4-sulfonic acid functionalized silver nanoparticles (ANS-AgNPs). The presence of Cd{sup 2+} induces the aggregation of ANS-AgNPs through cooperative metal–ligand interaction. As a result, the characteristic surface plasmon resonance (SPR) peak of ANS-AgNPs at 390 nm was red-shifted to 580 nm, yielding a color change from bright yellow to reddish-brown. The color change is monitored by UV–Vis spectrometer and can be directly read out by the naked eye. Under the optimized conditions, a good linear relationship (correlation coefficient R = 0.997) was obtained between the ratio of the absorbance at 580 nm to that at 390 nm (A{sub 580nm}/A{sub 390nm}) and the concentration of Cd{sup 2+} over the range of 1.0–10 μM with detection limit of 87 nM. The proposed method is simple and efficient, which has been applied for determining Cd{sup 2+} in milk powder, serum, and lake water with satisfactory results.

  7. PRINCIPLE OF VALIDATION OF MULTILEVEL RGB COLORIMETRIC SYSTEMS OF REMOTE SENSING

    OpenAIRE

    Lala Rustam Bekirova

    2013-01-01

    The possibility of development of two-level RGB colorimetric systems of remote sensing is analyzed. The principle of validation in multi-level RGB colorimetric systems taking into account the effect of metamerizm is formulated

  8. PRINCIPLE OF VALIDATION OF MULTILEVEL RGB COLORIMETRIC SYSTEMS OF REMOTE SENSING

    Directory of Open Access Journals (Sweden)

    Lala Rustam Bekirova

    2013-12-01

    Full Text Available The possibility of development of two-level RGB colorimetric systems of remote sensing is analyzed. The principle of validation in multi-level RGB colorimetric systems taking into account the effect of metamerizm is formulated

  9. Rapid validated HPTLC method for estimation of betulinic acid in Nelumbo nucifera (Nymphaeaceae) rhizome extract.

    Science.gov (United States)

    Mukherjee, Debajyoti; Kumar, N Satheesh; Khatua, Taraknath; Mukherjee, Pulok K

    2010-01-01

    Betulinic acid (pentacyclic triterpenoid) is an important marker component present in Nelumbo nucifera Gaertn. rhizome. N. nucifera rhizome has several medicinal uses including hypoglycaemic, antidiarrhoeal, antimicrobial, diuretic, antipyretic, psychopharmacological activities. To establish a simple, sensitive, reliable, rapid and validated high-performance thin-layer chromatography method for estimation of betulinic acid in hydro-alcoholic extract of N. nucifera Gaertn. rhizome. The separation was carried out on a thin-layer chromatography aluminium plate pre-coated with silica gel 60F(254) , eluted with chloroform, methanol and formic acid (49 : 1 : 1 v/v). Post chromatographic derivatisation was done with anisaldehyde-sulphuric acid reagent and densitometric scanning was performed using a Camag TLC scanner III, at 420 nm. The system was found to produce a compact spot for betulinic acid (R(f) = 0.30). A good linear precision relationship between the concentrations (2-10 µg) and peak areas were obtained with the correlation coefficient (r) of 0.99698. The limit of detection and limit of quantification of betulinic acid were detected to be 0.4 and 2.30 µg per spot. The percentage of recovery was found to be 98.36%. The percentage relative standard deviations of intra-day and inter-day precisions were 0.82-0.394 and 0.85-0.341, respectively. This validated HPTLC method provides a new and powerful approach to estimate betulinic acid as phytomarker in the extract. Copyright © 2010 John Wiley & Sons, Ltd.

  10. A rapid method for assessing the environmental performance of commercial farms in the Pampas of Argentina.

    Science.gov (United States)

    Viglizzo, E F; Frank, F; Bernardos, J; Buschiazzo, D E; Cabo, S

    2006-06-01

    The generation of reliable updated information is critical to support the harmonization of socio-economic and environmental issues in a context of sustainable development. The agro-environmental assessment and management of agricultural systems often relies on indicators that are necessary to make sound decisions. This work aims to provide an approach to (a) assess the environmental performance of commercial farms in the Pampas of Argentina, and (b) propose a methodological framework to calculate environmental indicators that can rapidly be applied to practical farming. 120 commercial farms scattered across the Pampas were analyzed in this study during 2002 and 2003. Eleven basic indicators were identified and calculation methods described. Such indicators were fossil energy (FE) use, FE use efficiency, nitrogen (N) balance, phosphorus (P) balance, N contamination risk, P contamination risk, pesticide contamination risk, soil erosion risk, habitat intervention, changes in soil carbon stock, and balance of greenhouse gases. A model named Agro-Eco-Index was developed on a Microsoft-Excel support to incorporate on-farm collected data and facilitate the calculation of indicators by users. Different procedures were applied to validate the model and present the results to the users. Regression models (based on linear and non-linear models) were used to validate the comparative performance of the study farms across the Pampas. An environmental dashboard was provided to represent in a graphical way the behavior of farms. The method provides a tool to discriminate environmentally friendly farms from those that do not pay enough attention to environmental issues. Our procedure might be useful for implementing an ecological certification system to reward a good environmental behavior in society (e.g., through tax benefits) and generate a commercial advantage (e.g., through the allocation of green labels) for committed farmers.

  11. A novel method for rapidly isolating microbes that suppress soil-borne phytopathogens

    Science.gov (United States)

    Cooper, Sarah; Agnew, Linda; Pereg, Lily

    2016-04-01

    Seedling establishment faces a large number of challenges related to soil physical properties as well as to fungal root diseases. It is extremely difficult to eliminate fungal pathogens from soils where their populations are established due to the persistent nature of their spores and since fumigation of resident fungi is very ineffective in clay-containing soils. Therefore it is necessary to find ways to overcome disease in areas where the soils are infected with fungal phytopathogens. The phenomenon of disease suppressive soils, where the pathogen is present but no disease observed, suggests that microbial antagonism in the soil may lead to the suppression of the growth of fungal pathogens. There are also cases in the literature where soil microorganisms were isolated that suppress the growth of phytopathogens. Antibiosis is one of the most important mechanisms responsible for fungal antagonism, with some significant antifungal compounds involved including antibiotics, volatile organic compounds, hydrogen cyanide and lytic enzymes. Isolation of pathogen-suppressive microorganisms from the soil is time consuming and tedious. We established a simple method for direct isolation of soil microbes (bacteria and fungi) that suppress fungal phytopathogens as well as procedures for confirmation of disease suppression. We will discuss such methods, which were so far tested with the cotton fungal pathogens Thielaviopsis basicola, Verticillium dahliae and Fusarium oxysporum and Verticillium fungicola. We have isolated a diversity of T. basicola-suppressive fungi and bacteria from two vastly different soil types. Identification of the antagonistic isolates revealed that they are a diverse lot, some belong to groups known to be suppressive of a wide range of fungal pathogens, endorsing the power of this technique to rapidly and directly isolate soil-borne microbes antagonistic to a wide variety of fungal pathogens.

  12. A simple and rapid flow cytometric method for detection of porcine cell surface markers.

    Science.gov (United States)

    Stabel, T J; Bolin, S R; Pesch, B A; Rahner, T E

    2000-11-01

    The objective of this study was to develop a rapid and reliable method for flow cytometric analysis of porcine whole blood cells. Fifty-microliters of heparin- or EDTA-treated whole blood was added to wells of a round-bottom 96-well microtitration plate. Each well contained 10 microl of an appropriate dilution of four different antibodies (40 microl total; two primary monoclonal antibodies and two fluorescent-labeled secondary antibodies). For convenience, the antibody mixture could be added to plates 1-2 days prior to assay and stored at 4 degrees C. Once whole blood was added to wells, plates were mixed gently, placed in a sealed bag and incubated in the dark at room temperature for 20 min. Contents of wells were then transferred to polystyrene tubes containing 2 ml of 1.5% formalin in distilled water and mixed gently. Cells were fixed for a minimum of 30 min and then stored in the dark at 4 degrees C until analysis by flow cytometry. Analysis of cell samples may be done up to 3 days after fixation. Results indicate that the percentages of Class I, Class II, CD3, CD8, CD4, CD45, monocyte, gamma-delta T-cell populations, and total number of granulocytes identified using this method were comparable to standard values or to values obtained following separation of white blood cells from red blood cells. The percentage of labeled B-cells was lower than standard values. Total assay time from receipt of blood to acquisition of data by flow cytometry required less than 2 h. This modified assay was shown to be simple, reliable, and useful for screening large numbers of porcine samples in a minimal period of time.

  13. The colorimetric determination of selectively cleaved adenosines and guanosines in DNA oligomers using bicinchoninic acid and copper.

    Science.gov (United States)

    Thomas, Elizabeth M; Testa, Stephen M

    2017-01-01

    Colorimetric methods combined with color-changing chemical probes are widely used as simple yet effective tools for identifying and quantifying a wide variety of molecules in solution. For nucleic acids (DNA and RNA), perhaps the most commonly used colorimetric probe is potassium permanganate, which can be used to identify single-stranded pyrimidines (thymine and cytosine) in polymers. Unfortunately, permanganate is not an effective probe for identifying purines (adenine and guanine), especially in the presence of the more reactive pyrimidines. Therefore, robust methods for discriminating between the purines remain elusive, thereby creating a barrier toward developing more complex colorimetric applications. In this proof-of-principle study, we demonstrate that bicinchoninic acid (BCA) and copper, when combined with purine-specific chemical cleavage reactions, can be a colorimetric probe for the identification and quantification of adenosines and/or guanosines in single-stranded DNA oligomers, even in the presence of pyrimidines. Furthermore, the reactions are stoichiometric, which allows for the quantification of the number of adenosines and/or guanosines in these oligomers. Because the BCA/copper reagent detects the reducing sugar, 2-deoxyribose, that results from the chemical cleavage of a given nucleotide's N-glycosidic bond, these colorimetric assays are effectively detecting apurinic sites in DNA oligomers, which are known to occur via DNA damage in biological systems. We demonstrate that simple digital analysis of the color-changing chromophore (BCA/copper) is all that is necessary to obtain quantifiable and reproducible data, which indicates that these assays should be broadly accessible.

  14. A rapid method for detection of five known mutations associated with aminoglycoside-induced deafness.

    Science.gov (United States)

    Bardien, Soraya; Human, Hannique; Harris, Tashneem; Hefke, Gwynneth; Veikondis, Rene; Schaaf, H Simon; van der Merwe, Lize; Greinwald, John H; Fagan, Johan; de Jong, Greetje

    2009-01-13

    South Africa has one of the highest incidences of multidrug-resistant tuberculosis (MDR-TB) in the world. Concomitantly, aminoglycosides are commonly used in this country as a treatment against MDR-TB. To date, at least five mutations are known to confer susceptibility to aminoglycoside-induced hearing loss. The aim of the present study was to develop a rapid screening method to determine whether these mutations are present in the South African population. A multiplex method using the SNaPshot technique was used to screen for five mutations in the MT-RNR1 gene: A1555G, C1494T, T1095C, 961delT+C(n) and A827G. A total of 204 South African control samples, comprising 98 Mixed ancestry and 106 Black individuals were screened for the presence of the five mutations. A robust, cost-effective method was developed that detected the presence of all five sequence variants simultaneously. In this pilot study, the A1555G mutation was identified at a frequency of 0.9% in the Black control samples. The 961delT+C(n) variant was present in 6.6% of the Black controls and 2% of the Mixed ancestry controls. The T1095C, C1494T and A827G variants were not identified in any of the study participants. The frequency of 0.9% for the A1555G mutation in the Black population in South Africa is of concern given the high incidence of MDR-TB in this particular ethnic group. Future larger studies are warranted to determine the true frequencies of the aminoglycoside deafness mutations in the general South African population. The high frequencies of the 961delT+C(n) variant observed in the controls suggest that this change is a common non-pathogenic polymorphism. This genetic method facilitates the identification of individuals at high risk of developing hearing loss prior to the start of aminoglycoside therapy. This is important in a low-resource country like South Africa where, despite their adverse side-effects, aminoglycosides will continue to be used routinely and are accompanied with very

  15. ADVANTAGES OF RAPID METHOD FOR DETERMINING SCALE MASS AND DECARBURIZED LAYER OF ROLLED COIL STEEL

    Directory of Open Access Journals (Sweden)

    E. V. Parusov

    2016-08-01

    Full Text Available Purpose. To determine the universal empirical relationships that allow for operational calculation of scale mass and decarbonized layer depth based on the parameters of the technological process for rolled coil steel production. Methodology. The research is carried out on the industrial batches of the rolled steel of SAE 1006 and SAE 1065 grades. Scale removability was determined in accordance with the procedure of «Bekaert» company by the specifi-cations: GA-03-16, GA-03-18, GS-03-02, GS-06-01. The depth of decarbonized layer was identified in accordance with GOST 1763-68 (M method. Findings. Analysis of experimental data allowed us to determine the rational temperature of coil formation of the investigated steel grades, which provide the best possible removal of scale from the metal surface, a minimal amount of scale, as well as compliance of the metal surface color with the require-ments of European consumers. Originality. The work allowed establishing correlation of the basic quality indicators of the rolled coil high carbon steel (scale mass, depth of decarbonized layer and inter-laminar distance in pearlite with one of the main parameters (coil formation temperature of the deformation and heat treatment mode. The re-sulting regression equations, without metallographic analysis, can be used to determine, with a minimum error, the quantitative values of the total scale mass, depth of decarbonized layer and the average inter-lamellar distance in pearlite of the rolled coil high carbon steel. Practical value. Based on the specifications of «Bekaert» company (GA-03-16, GA-03-18, GS-03-02 and GS-06-01 the method of testing descaling by mechanical means from the surface of the rolled coil steel of low- and high-carbon steel grades was developed and approved in the environment of PJSC «ArcelorMittal Kryvyi Rih». The work resulted in development of the rapid method for determination of total and remaining scale mass on the rolled coil steel

  16. Label-free aptamer-based colorimetric detection of mercury ions in aqueous media using unmodified gold nanoparticles as colorimetric probe.

    Science.gov (United States)

    Li, Li; Li, Baoxin; Qi, Yingying; Jin, Yan

    2009-04-01

    We report a simple and sensitive aptamer-based colorimetric detection of mercury ions (Hg(2+)) using unmodified gold nanoparticles as colorimetric probe. It is based on the fact that bare gold nanoparticles interact differently with short single-strand DNA and double-stranded DNA. The anti-Hg(2+) aptamer is rich in thymine (T) and readily forms T-Hg(2+)-T configuration in the presence of Hg(2+). By measuring color change or adsorption ratio, the bare gold nanoparticles can effectively differentiate the Hg(2+)-induced conformational change of the aptamer in the presence of a given salt with high concentration. The assay shows a linear response toward Hg(2+) concentration through a five-decade range of 1 x 10(-4) mol L(-1) to 1 x 10(-9) mol L(-1). Even with the naked eye, we could identify micromolar Hg(2+) concentrations within minutes. By using the spectrometric method, the detection limit was improved to the nanomolar range (0.6 nM). The assay shows excellent selectivity for Hg(2+) over other metal cations including K(+), Ba(2+), Ni(2+), Pb(2+), Cu(2+), Cd(2+), Mg(2+), Ca(2+), Zn(2+), Al(3+), and Fe(3+). The major advantages of this Hg(2+) assay are its water-solubility, simplicity, low cost, visual colorimetry, and high sensitivity. This method provides a potentially useful tool for the Hg(2+) detection.

  17. One-step, room temperature, colorimetric melamine sensing using an in-situ formation of silver nanoparticles through modified Tollens process

    Science.gov (United States)

    Wang, Huiying; Chen, Dinglong; Yu, Longquan; Chang, Ming; Ci, Lijie

    2015-02-01

    We have developed a rapid, sensitive, one-step, and selective colorimetric detection method for melamine (MEL) in milk powder based upon an in-situ formation of silver nanoparticles (AgNPs) through modified Tollens process at room temperature. The triazine ring N atoms of MEL molecule were strategically designed to complex the Ag+ through electron donor-acceptor interaction. During the AgNPs formation procedure, the MEL molecule, which has been covalently bonded with the Ag+ ions, was adsorbed to the surface of as-prepared AgNPs, resulting in the aggregation of the adjacent AgNPs with detectable decreases of absorption signal. The concentration of MEL can be determined with the naked eye or a UV-vis spectrometer at which the yellow-to-brown color change associated with aggregate enhancement takes place. This method enables rapid (less than 30 min) and sensitive (limit of detection, LOD, 10 nM) detection, and it was also able to discriminate MEL from sixteen other milk relevant coexisting compounds. This assay does not utilize organic cosolvents, enzymatic reactions, light-sensitive dye molecules, lengthy protocols, or sophisticated instrumentation thereby overcoming some of the limitations of conventional methods.

  18. A colorimetric tetrathiafulvalene-calix 4 pyrrole anion sensor

    DEFF Research Database (Denmark)

    Nielsen, K. A.

    2012-01-01

    The interaction and colorimetric sensing properties of a tetrathiafulvalene substituted calix[4]pyrrole sensor with anions were investigated using H-1 NMR and absorption spectroscopic techniques. Visual color changes were observed upon addition of different anions (Cl-, Br-, CN-, and AcO-) to a s......The interaction and colorimetric sensing properties of a tetrathiafulvalene substituted calix[4]pyrrole sensor with anions were investigated using H-1 NMR and absorption spectroscopic techniques. Visual color changes were observed upon addition of different anions (Cl-, Br-, CN-, and Ac......O-) to a solution of the sensor. (C) 2012 Elsevier Ltd. All rights reserved....

  19. Development a rapid and accurate multiplex real time PCR method for the detection Chlamydia trachomatis and Mycoplasma hominis.

    Science.gov (United States)

    Safarkar, Roya; Mehrabadi, Jalil Fallah; Noormohammadi, Zahra; Mirnejad, Reza

    2017-11-01

    Sexually transmitted diseases easily spread among sexually active people and often have no symptoms. Rapid and accurate method for detecting these infections are necessary in early stages. The traditional detection methods of them are difficult and time-consuming. In this study, multiplex real time PCR was optimized for rapid identification of Chlamydia trachomatis and Mycoplasma hominis in a single tube and was performed with our designed primers. The sensitivity test was carried out to designed primers with diluted genomic DNA. To defined the specificity, non STD bacteria were used as DNA template. This study indicated that the developed multiplex real time PCR can be an effective alternative procedure to the conventional methods for rapid and accurate identification of C Chlamydia trachomatis and Mycoplasma hominis. Multiplex real-time PCR Results of them were checked with melting curves. The sensitivity of our designed primer by multiplex real time PCR for Chlamydia trachomatis and Mycoplasma hominis were 4.78×1010 and 8.35×1010 , respectively, Which the primers did not amplify any product from a non-STD species. Multiplex real time PCR by our new primers and analysis of melting curves were successfully usable for rapid and accurate detection of Chlamydia trachomatis and Mycoplasma hominis. This assay instead of traditional culture method, has considerable potential to be rapid, accurate and highly sensitive molecular diagnostic tool for simultaneous and direct detection. © 2017 Wiley Periodicals, Inc.

  20. Development of Novel Method for Rapid Extract of Radionuclides from Solution Using Polymer Ligand Film

    Science.gov (United States)

    Rim, Jung H.

    Accurate and fast determination of the activity of radionuclides in a sample is critical for nuclear forensics and emergency response. Radioanalytical techniques are well established for radionuclides measurement, however, they are slow and labor intensive, requiring extensive radiochemical separations and purification prior to analysis. With these limitations of current methods, there is great interest for a new technique to rapidly process samples. This dissertation describes a new analyte extraction medium called Polymer Ligand Film (PLF) developed to rapidly extract radionuclides. Polymer Ligand Film is a polymer medium with ligands incorporated in its matrix that selectively and rapidly extract analytes from a solution. The main focus of the new technique is to shorten and simplify the procedure necessary to chemically isolate radionuclides for determination by alpha spectrometry or beta counting. Five different ligands were tested for plutonium extraction: bis(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP]), di(2-ethyl hexyl) phosphoric acid (HDEHP), trialkyl methylammonium chloride (Aliquat-336), 4,4'(5')-di-t-butylcyclohexano 18-crown-6 (DtBuCH18C6), and 2-ethylhexyl 2-ethylhexylphosphonic acid (HEH[EHP]). The ligands that were effective for plutonium extraction further studied for uranium extraction. The plutonium recovery by PLFs has shown dependency on nitric acid concentration and ligand to total mass ratio. H2DEH[MDP] PLFs performed best with 1:10 and 1:20 ratio PLFs. 50.44% and 47.61% of plutonium were extracted on the surface of PLFs with 1M nitric acid for 1:10 and 1:20 PLF, respectively. HDEHP PLF provided the best combination of alpha spectroscopy resolution and plutonium recovery with 1:5 PLF when used with 0.1M nitric acid. The overall analyte recovery was lower than electrodeposited samples, which typically has recovery above 80%. However, PLF is designed to be a rapid field deployable screening technique and consistency is more important

  1. Rapid detection of coliforms in drinking water of Arak city using multiplex PCR method in comparison with the standard method of culture (Most Probably Number)

    OpenAIRE

    fatemeh, Dehghan; Reza, Zolfaghari Mohammad; Mohammad, Arjomandzadegan; Salomeh, Kalantari; Reza, Ahmari Gholam; Hossein, Sarmadian; Maryam, Sadrnia; Azam, Ahmadi; Mana, Shojapoor; Negin, Najarian; Reza, Kasravi Alii; Saeed, Falahat

    2014-01-01

    Objective: To analyse molecular detection of coliforms and shorten the time of PCR. Methods: Rapid detection of coliforms by amplification of lacZ and uidA genes in a multiplex PCR reaction was designed and performed in comparison with most probably number (MPN) method for 16 artificial and 101 field samples. The molecular method was also conducted on isolated coliforms from positive MPN samples; standard sample for verification of microbial method certificated reference material; isolated...

  2. A rapid method for an offline glycerol determination during microbial fermentation

    Directory of Open Access Journals (Sweden)

    Jennifer Kuhn

    2015-05-01

    Conclusions: With this rapid assay, glycerol could be detected easily in microbial fermentation broth. It is reliable over a wide concentration range including advantages such as an easy assay set-up, a short assay time and no sample pretreatment.

  3. Problems with rapid agglutination methods for identification of Staphylococcus aureus when Staphylococcus saprophyticus is being tested.

    OpenAIRE

    Gregson, D B; Low, D E; Skulnick, M; Simor, A E

    1988-01-01

    Six rapid agglutination tests for identification of Staphylococcus aureus were evaluated by using 62 strains of S. aureus, 63 strains of S. saprophyticus, and 67 strains of other coagulase-negative staphylococci. S. saprophyticus was responsible for 19 of 26 false-positive results and 20 uninterpretable reactions. Thus, urinary staphylococcal isolates that are positive by rapid agglutination tests may require other confirmatory tests for the identification of possible S. saprophyticus.

  4. A Rapid and Reliable Method for Total Protein Extraction from Succulent Plants for Proteomic Analysis.

    Science.gov (United States)

    Lledías, Fernando; Hernández, Felipe; Rivas, Viridiana; García-Mendoza, Abisaí; Cassab, Gladys I; Nieto-Sotelo, Jorge

    2017-08-01

    Crassulacean acid metabolism plants have some morphological features, such as succulent and reduced leaves, thick cuticles, and sunken stomata that help them prevent excessive water loss and irradiation. As molecular constituents of these morphological adaptations to xeric environments, succulent plants produce a set of specific compounds such as complex polysaccharides, pigments, waxes, and terpenoids, to name a few, in addition to uncharacterized proteases. Since all these compounds interfere with the analysis of proteins by electrophoretic techniques, preparation of high quality samples from these sources represents a real challenge. The absence of adequate protocols for protein extraction has restrained the study of this class of plants at the molecular level. Here, we present a rapid and reliable protocol that could be accomplished in 1 h and applied to a broad range of plants with reproducible results. We were able to obtain well-resolved SDS/PAGE protein patterns in extracts from different members of the subfamilies Agavoideae (Agave, Yucca, Manfreda, and Furcraea), Nolinoideae (Dasylirion and Beucarnea), and the Cactaceae family. This method is based on the differential solubility of contaminants and proteins in the presence of acetone and pH-altered solutions. We speculate about the role of saponins and high molecular weight carbohydrates to produce electrophoretic-compatible samples. A modification of the basic protocol allowed the analysis of samples by bidimensional electrophoresis (2DE) for proteomic analysis. Furostanol glycoside 26-O-β-glucosidase (an enzyme involved in steroid saponin synthesis) was successfully identified by mass spectrometry analysis and de novo sequencing of a 2DE spot from an Agave attenuata sample.

  5. Biogas production from ensiled meadow grass; effect of mechanical pretreatments and rapid determination of substrate biodegradability via physicochemical methods

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Angelidaki, Irini

    2015-01-01

    As the biogas sector is rapidly expanding, there is an increasing need in finding new alternative feedstock to biogas plants. Meadow grass can be a suitable co-substrate and if ensiled it can be supplied to biogas plants continuously throughout the year. Nevertheless, this substrate is quite reca...... the methods, electrical conductivity test showed the most promising calibration statistics (R2 = 0.68)....... increased the methane productivity and the increase ranged from 8% to 25%. The best mechanical pretreatment was the usage of two coarse mesh grating plates. Additionally, simple analytical methods were conducted to investigate the possibility of rapidly determining the methane yield of meadow grass. Among...

  6. A rapid and quantitative method to detect human circulating tumor cells in a preclinical animal model.

    Science.gov (United States)

    Tu, Shih-Hsin; Hsieh, Yi-Chen; Huang, Li-Chi; Lin, Chun-Yu; Hsu, Kai-Wen; Hsieh, Wen-Shyang; Chi, Wei-Ming; Lee, Chia-Hwa

    2017-06-23

    As cancer metastasis is the deadliest aspect of cancer, causing 90% of human deaths, evaluating the molecular mechanisms underlying this process is the major interest to those in the drug development field. Both therapeutic target identification and proof-of-concept experimentation in anti-cancer drug development require appropriate animal models, such as xenograft tumor transplantation in transgenic and knockout mice. In the progression of cancer metastasis, circulating tumor cells (CTCs) are the most critical factor in determining the prognosis of cancer patients. Several studies have demonstrated that measuring CTC-specific markers in a clinical setting (e.g., flow cytometry) can provide a current status of cancer development in patients. However, this useful technique has rarely been applied in the real-time monitoring of CTCs in preclinical animal models. In this study, we designed a rapid and reliable detection method by combining a bioluminescent in vivo imaging system (IVIS) and quantitative polymerase chain reaction (QPCR)-based analysis to measure CTCs in animal blood. Using the IVIS Spectrum CT System with 3D-imaging on orthotropic-developed breast-tumor-bearing mice. In this manuscript, we established a quick and reliable method for measuring CTCs in a preclinical animal mode. The key to this technique is the use of specific human and mouse GUS primers on DNA/RNA of mouse peripheral blood under an absolute qPCR system. First, the high sensitivity of cancer cell detection on IVIS was presented by measuring the luciferase carried MDA-MB-231 cells from 5 to 5x10(11) cell numbers with great correlation (R(2) = 0.999). Next, the MDA-MB-231 cell numbers injected by tail vein and their IVIS radiance signals were strongly corrected with qPCR-calculated copy numbers (R(2) > 0.99). Furthermore, by applying an orthotropic implantation animal model, we successfully distinguished xenograft tumor-bearing mice and control mice with a significant difference (p < 0

  7. Comparative analysis of two colorimetric assays in dental pulp cell density

    Science.gov (United States)

    Nedel, F.; Soki, F.N.; Conde, M.C.M.; Zeitlin, B.D.; Tarquinio, S.B.C.; Nör, J.E.; Seixas, F.K.; Demarco, F.F.

    2013-01-01

    Aim To compare and contrast two colorimetric assays used for measurement of proliferation using two dental pulp cell types: dental pulp stem cells (DPSC) and human dental pulp fibroblasts (HDPF). Methodology DPSC or HDPF were seeded at 0.25 × 104 cells/well in 96-well plates. Cell proliferation was evaluated after 24-72 hours. At the end of the experimental period, the Sulforhodamine B (SRB) assay or a water-soluble tetrazolium salt (WST-1) assay was performed. Optical densities were determined in a microplate reader (Genius; TECAN). Data were analyzed by Student’s t-test (comparison between cell types), and one-way ANOVA followed by Tukey test (time point intervals). Pearson’ correlation tests were performed to compare the two assays for each cell line. Results Both assays showed that DPSC had higher proliferation rates than HDPF. A positive significant correlation between the two colorimetric assays tested for both cell types DPSC (Pearson’s Correlation Coefficient=0.847; passay is therefore one of practical application. SRB stained plates may be dried and stored so may have utility in laboratories where data may require review or when access to analytical equipment is limited. WST-1 assays have the benefit of both ease and speed and may have utility in laboratories requiring either high throughput or rapid analyses. PMID:20880134

  8. Highly sensitive fluorescent and colorimetric pH sensor based on polyethylenimine-capped silver nanoclusters.

    Science.gov (United States)

    Qu, Fei; Li, Nian Bing; Luo, Hong Qun

    2013-01-29

    Silver nanoclusters capped by hyperbranched polyethylenimine (PEI) have been developed as a highly sensitive fluorescent and colorimetric pH sensor. The probe responds rapidly to pH fluctuations and has such absorption characteristics that the color changes from the colorless or a nearly colorless state to a colored state with increasing acidity, so PEI-capped Ag nanoclusters could be used as a color indicator for colorimetric pH detection. Quantitatively, the fluorescence intensity of PEI-capped Ag nanoclusters exhibits a linear fashion over the pH range of 5.02-7.96 and increases by around 10-fold approximately with greater fluorescence at higher pH values. The repulsion development and conformational change of PEI with decreasing pH induce the aggregation of Ag nanoclusters, leading to an obvious color change and fluorescence quenching of Ag nanoclusters at low pH values. As expected, the pH probe is also sensitive to the different buffer solutions, except for those containing some anions that could react with Ag nanoclusters. Besides, the ionic strength of the buffers has a little influence on the pH-responsive behavior. Our pH sensor with nanoscaled physical dimensions would be a promising candidate in the applications in biological, medical, and pharmaceutical fields.

  9. Silver nanoplates-based colorimetric iodide recognition and sensing using sodium thiosulfate as a sensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xinyan; Chen, Shu, E-mail: chenshumail@gmail.com; Tang, Jian; Xiong, Yuan; Long, Yunfei, E-mail: l_yunfei927@163.com

    2014-05-01

    Highlights: • A new colorimetric iodide detection strategy based on triangular Ag nanoplate. • Sodium thiosulfate performed as a sensitizer. • Formation of insoluble AgI on the surface of Ag nanoplate. • This method has the advantages of good selectivity and high sensitivity. Abstract: A colorimetric method for the recognition and sensing of iodide ions (I⁻) has been developed by utilizing the reactions between triangular silver nanoplates (TAg-NPs) and I⁻ in the presence of sodium thiosulfate (Na₂S₂O₃). Specifically, I⁻ together with Na₂S₂O₃ can induce protection of TAg-NPs owing to the formation of insoluble AgI, as confirmed by the high-resolution transmission electron microscopy (HRTEM). In the absence of Na₂S₂O₃, the etching reactions on TAg-NPs were observed not only by I⁻ but also other halides ions. The Na₂S₂O₃ plays as a sensitizer in this system, which improved the selectivity and sensitivity. The desired colorimetric detection can be achieved by measuring the change of the absorption peak wavelength corresponding to localized surface plasmon resonance (LSPR) with UV–vis spectrophotometer or recognized by naked eye observation. The results show that the shift of the maximum absorption wavelength (Δλ) of the TAg-NPs/Na₂S₂O₃/I⁻ mixture was proportional to the concentration of I⁻ in the range 1.0 × 10⁻⁹–1.0 × 10⁻⁶ mol L⁻¹. Moreover, no other ions besides I⁻ can induce an eye discernible color change as low as 1.0 × 10⁻⁷ mol L⁻¹. Finally, this method was successfully applied for I⁻ determination in kelp samples.

  10. High throughput, colorimetric screening of microbial ester biosynthesis reveals high ethyl acetate production from Kluyveromyces marxianus on C5, C6, and C12 carbon sources.

    Science.gov (United States)

    Löbs, Ann-Kathrin; Lin, Jyun-Liang; Cook, Megan; Wheeldon, Ian

    2016-10-01

    Advances in genome and metabolic pathway engineering have enabled large combinatorial libraries of mutant microbial hosts for chemical biosynthesis. Despite these advances, strain development is often limited by the lack of high throughput functional assays for effective library screening. Recent synthetic biology efforts have engineered microbes that synthesize acetyl and acyl esters and many yeasts naturally produce esters to significant titers. Short and medium chain volatile esters have value as fragrance and flavor compounds, while long chain acyl esters are potential replacements for diesel fuel. Here, we developed a biotechnology method for the rapid screening of microbial ester biosynthesis. Using a colorimetric reaction scheme, esters extracted from fermentation broth were quantitatively converted to a ferric hydroxamate complex with strong absorbance at 520 nm. The assay was validated for ethyl acetate, ethyl butyrate, isoamyl acetate, ethyl hexanoate, and ethyl octanoate, and achieved a z-factor of 0.77. Screening of ethyl acetate production from a combinatorial library of four Kluyveromyces marxianus strains on seven carbon sources revealed ethyl acetate biosynthesis from C5, C6, and C12 sugars. This newly adapted method rapidly identified novel properties of K. marxianus metabolism and promises to advance high throughput microbial strain engineering for ester biosynthesis. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Use of spectral sensitivity variability in reflectance recovery from colorimetric information.

    Science.gov (United States)

    Amiri, Morteza Maali; Fairchild, Mark D

    2017-07-01

    There have been numerous methods for accessing the reflectance spectra; some methods enable one to obtain the spectra directly, such as using a spectrophotometer, hyper-spectral camera, and so forth. Even though the accuracy by which the spectra are obtained can be very high, the high price of these methods could pose an obstacle. On the other hand, there has been an interest in estimation of the spectral reflectance from colorimetric information that is more easily attainable; the accuracy in this case might not be as high but these methods are the most cost efficient. It is aimed, in this paper, to amalgamate the low price and high accuracy of the preceding approaches through relating spectral estimation to spectral sensitivity variability. The work is split into two major parts. The first part of the paper describes spectral sensitivity variability of humans and cameras in a theoretical manner and how it can be used in spectral recovery. In the second part, an attempt is made to extend the theory to real situations. At the end, it is shown how increasing the number of disparate colorimetric data of a specific object using the proposed methods aids in estimating spectral reflectance more accurately in a manner comparable to multi-spectral cameras.

  12. Colorimetric Enzymatic Assay of L-Malic Acid Using Dehydrogenase from Baker’s Yeast

    Directory of Open Access Journals (Sweden)

    Cecilia Laluce

    2008-01-01

    Full Text Available A colorimetric method has been developed and optimized to measure L-malic acid in samples of fruit juices and wine. This method is based on oxidation of the analyte, catalyzed by malate dehydrogenase (MDH from dry baker’s yeast, and in combination with the reduction of a tetrazolium salt (MTT: 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide. In the present study, the method exhibited sensitivity in the range of 500–4000 mM of L-malic acid in the reaction cuvette, with the lower detection limit of 6.7·10^-2 g/L, the upper limit of 53.6·10^-2 g/L and a maximum standard deviation of only 2.5 % for the analyzed samples. The MDH activity from baker’s yeast was also optimized, the enzyme showed a high stability at pH=8.0–9.0 and the activity was maintained completely at temperatures up to 40 °C for 1 hour. The results show that the colorimetric method using enzymatic preparations from dry baker’s yeast is a simple and low-cost method with possibility of wide application

  13. Photonic Crystal Structures with Tunable Structure Color as Colorimetric Sensors

    Directory of Open Access Journals (Sweden)

    Ke-Qin Zhang

    2013-03-01

    Full Text Available Colorimetric sensing, which transduces environmental changes into visible color changes, provides a simple yet powerful detection mechanism that is well-suited to the development of low-cost and low-power sensors. A new approach in colorimetric sensing exploits the structural color of photonic crystals (PCs to create environmentally-influenced color-changeable materials. PCs are composed of periodic dielectrics or metallo-dielectric nanostructures that affect the propagation of electromagnetic waves (EM by defining the allowed and forbidden photonic bands. Simultaneously, an amazing variety of naturally occurring biological systems exhibit iridescent color due to the presence of PC structures throughout multi-dimensional space. In particular, some kinds of the structural colors in living organisms can be reversibly changed in reaction to external stimuli. Based on the lessons learned from natural photonic structures, some specific examples of PCs-based colorimetric sensors are presented in detail to demonstrate their unprecedented potential in practical applications, such as the detections of temperature, pH, ionic species, solvents, vapor, humidity, pressure and biomolecules. The combination of the nanofabrication technique, useful design methodologies inspired by biological systems and colorimetric sensing will lead to substantial developments in low-cost, miniaturized and widely deployable optical sensors.

  14. Testing of Colorimetric Tubes for Nitrogen Dioxide and Monomethylhydrazine.

    Science.gov (United States)

    Diamond, Philip

    Colorimetric tubes for nitrogen dioxide (NO2) and monomethylhydrazine (MMH) were tested for accuracy and results indicate that at the levels checked the tubes' average deviation was plus or minus 20 percent. Tube NO2 concentrations all read lower than the analyzed concentrations. MMH tubes read much higher than the analyzed concentration of 0.28…

  15. Electrospun fibre colorimetric probe based on gold nanoparticles for ...

    African Journals Online (AJOL)

    2014-11-20

    Nov 20, 2014 ... An on-site colorimetric probe, based on gold nanoparticles incorporated into electrospun polystyrene nanofibres, for the detection of oestrogenic compounds, as represented by 17β-estradiol, in dairy effluents is presented. The probe exhibited a significant absorption peak at 542 nm, ascribed to surface ...

  16. Haussdorff and hellinger for colorimetric sensor array classification

    DEFF Research Database (Denmark)

    Alstrøm, Tommy Sonne; Jensen, Bjørn Sand; Schmidt, Mikkel Nørgaard

    2012-01-01

    Development of sensors and systems for detection of chemical compounds is an important challenge with applications in areas such as anti-terrorism, demining, and environmental monitoring. A newly developed colorimetric sensor array is able to detect explosives and volatile organic compounds...

  17. Electrospun fibre colorimetric probe based on gold nanoparticles for ...

    African Journals Online (AJOL)

    An on-site colorimetric probe, based on gold nanoparticles incorporated into electrospun polystyrene nanofibres, for the detection of oestrogenic compounds, as represented by 17β-estradiol, in dairy effluents is presented. The probe exhibited a significant absorption peak at 542 nm, ascribed to surface plasmon resonance ...

  18. Colorimetric Assay Of Naproxen Tablets by Derivatization Using 4 ...

    African Journals Online (AJOL)

    A colorimetric assay of naproxen tablets based on chemical derivatization with the chromogenic reagent 4-carboxyl-2,6-dinitrobenzene diazonium ion was developed. The optimal reaction time was found to be 5 min at 30 oC after vortex mixing of the drug/reagent mixture for 10 s. The optimal analytical wavelength was ...

  19. Colorimetric control of photographic prints: the problem of fluorescence

    Science.gov (United States)

    Witt, Klaus

    2002-06-01

    The colorimetric control of photographic prints is an important issue of color reproduction quality. Concentration series of the three photographic dyes Yellow, Magenta and Cyan on photographic paper are very often measured without considering the optical quality of the substrate. However, this substrate, the photographic paper, produces problems for colorimetry because it emits luminenscent light from optical brighteners. Many instruments used in colorimetry are not adapted to measure such an output correctly. Here, an experimental investigation is presented which quantifies systematic shifts of spectral curves and colorimetric values of photographic paper and dyes for various measuring parameters. Several spectrophotometers equipped with different sources for irradiation such as Tungsten halogen lamp, Xenon flash lamp, D65 simulator, and two Xenon lamps with adjustable UV-filter were referenced against the results of two-monochromator spectrophotometer. In the photographic paper the largest color-difference extended to approximately 10 CIELAB-units between irradiation by a Tungsten halogen and a Xenon lamp. These differences diminished with increasing concentration of the photographic dyes, however, did not die away at the highest concentration of the dyes used. The correct colorimetric values for D65 irradiation were halfway between those for the two former lamps and near to measures received from Xenon lamp irraditoin with adjustable UV-filter. Therefore, such spectrophotometers may be used for colorimetric control of photographic prints to attain an accuracy below 3 CIELAB units, or else, two measurements with a Tungsten halogen and a Xenon lamp should be averaged.

  20. Dicyclohexylcarbodiimide as a cleaving agent for colorimetric determination of pyridyl and pyrimidinyl compounds

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S.C.

    1985-06-01

    By use of dicyclohexylcarbodiimide (DCC) and dimethylbarbituric acid (DMBA) as reagents, a colorimetric method for the determination of pyridyl and pyrimidinyl compounds has been established. DCC breaks the pyridine or pyrimidine ring to afford glutaconaldehyde or malonaldehyde and then reacts with DMBA to produce chromophores. These heterocycles could be determined by measuring the chromophores. The relative standard deviations obtained with different amounts of these compounds were in a range of 0.63 to 5.36% (n = 10). The reaction mechanism is also discussed. 22 references, 4 figures, 1 table.