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Sample records for acid detection methods

  1. Nucleic acid detection methods

    DOEpatents

    Smith, C.L.; Yaar, R.; Szafranski, P.; Cantor, C.R.

    1998-05-19

    The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3{prime}-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated. 18 figs.

  2. Nucleic Acid Detection Methods

    DOEpatents

    Smith, Cassandra L.; Yaar, Ron; Szafranski, Przemyslaw; Cantor, Charles R.

    1998-05-19

    The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3'-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated.

  3. Nucleic acid detection system and method for detecting influenza

    SciTech Connect

    Cai, Hong; Song, Jian

    2015-03-17

    The invention provides a rapid, sensitive and specific nucleic acid detection system which utilizes isothermal nucleic acid amplification in combination with a lateral flow chromatographic device, or DNA dipstick, for DNA-hybridization detection. The system of the invention requires no complex instrumentation or electronic hardware, and provides a low cost nucleic acid detection system suitable for highly sensitive pathogen detection. Hybridization to single-stranded DNA amplification products using the system of the invention provides a sensitive and specific means by which assays can be multiplexed for the detection of multiple target sequences.

  4. Rapid detection method for fusaric acid-producing species of Fusarium by PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusaric acid is a mycotoxin produced by species of the fungus Fusarium and can act synergistically with other Fusarium toxins. In order to develop a specific detection method for fusaric acid-producing fungus, PCR prim¬ers were designed to amplify FUB10, a transcription factor gene in fusaric acid ...

  5. A new method for quantitative determination of two uronic acids by CZE with direct UV detection.

    PubMed

    Xia, Yong-gang; Liang, Jun; Yang, Bing-you; Wang, Qiu-hong; Kuang, Hai-xue

    2011-09-01

    A new method using capillary zone electrophoresis was developed for the rapid quantification of two common uronic acids, galacturonic acid and glucuronic acid, based on utilization of an alkaline background electrolyte with reversed electroosmotic flow (EOF) within 16 min. The method relies on in-capillary reaction and direct UV detection at the wavelength 270 nm. The optimum electrolyte solution was prepared of 130 mm sodium hydroxide, 36 mm disodium hydrogen phosphate dihydrate and 0.5 mm cetyltrimethylammonium bromide. EOF was reversed to detect uronic acids and to improve the separation of neutral sugars. The established method was validated and the results showed good linearity, high precision and satisfactory sensitivity. The newly developed method was successfully applied to analyze galacturonic acid and glucuronic acid content in Forsythia suspensa polysaccharides. The method is fast since only sample hydrolysis and dilution are required in the sample preparation. PMID:21154888

  6. Methods for point-of-care detection of nucleic acid in a sample

    DOEpatents

    Bearinger, Jane P.; Dugan, Lawrence C.

    2015-12-29

    Provided herein are methods and apparatus for detecting a target nucleic acid in a sample and related methods and apparatus for diagnosing a condition in an individual. The condition is associated with presence of nucleic acid produced by certain pathogens in the individual.

  7. Nucleic acid detection kits

    DOEpatents

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

    2005-03-29

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

  8. Capillary electrophoresis method with UV-detection for analysis of free amino acids concentrations in food.

    PubMed

    Omar, Mei Musa Ali; Elbashir, Abdalla Ahmed; Schmitz, Oliver J

    2017-01-01

    Simple and inexpensive capillary electrophoresis with UV-detection method (CE-UV) was optimized and validated for determination of six amino acids namely (alanine, asparagine, glutamine, proline, serine and valine) for Sudanese food. Amino acids in the samples were derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-UV analysis. Labeling reaction conditions (100mM borate buffer at pH 8.5, labeling reaction time 60min, temperature 70°C and NBD-Cl concentration 40mM) were systematically investigated. The optimal conditions for the separation were 100mM borate buffer at pH 9.7 and detected at 475nm. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability) (RSD%) and accuracy (recovery). Good linearity was achieved for all amino acids (r(2)>0.9981) in the concentration range of 2.5-40mg/L. The LODs in the range of 0.32-0.56mg/L were obtained. Recoveries of amino acids ranging from 85% to 108%, (n=3) were obtained. The validated method was successfully applied for the determination of amino acids for Sudanese food samples. PMID:27507479

  9. Nucleic acid detection assays

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

    2005-04-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  10. Nucleic acid detection compositions

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James L.

    2008-08-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  11. Isothermal Amplification Methods for the Detection of Nucleic Acids in Microfluidic Devices

    PubMed Central

    Zanoli, Laura Maria; Spoto, Giuseppe

    2012-01-01

    Diagnostic tools for biomolecular detection need to fulfill specific requirements in terms of sensitivity, selectivity and high-throughput in order to widen their applicability and to minimize the cost of the assay. The nucleic acid amplification is a key step in DNA detection assays. It contributes to improving the assay sensitivity by enabling the detection of a limited number of target molecules. The use of microfluidic devices to miniaturize amplification protocols reduces the required sample volume and the analysis times and offers new possibilities for the process automation and integration in one single device. The vast majority of miniaturized systems for nucleic acid analysis exploit the polymerase chain reaction (PCR) amplification method, which requires repeated cycles of three or two temperature-dependent steps during the amplification of the nucleic acid target sequence. In contrast, low temperature isothermal amplification methods have no need for thermal cycling thus requiring simplified microfluidic device features. Here, the use of miniaturized analysis systems using isothermal amplification reactions for the nucleic acid amplification will be discussed. PMID:25587397

  12. Immunologic, spectrophotometric and nucleic acid based methods for the detection and quantification of airborne pollen

    PubMed Central

    Rittenour, William R.; Hamilton, Robert G.; Beezhold, Donald H.; Green, Brett J.

    2015-01-01

    Microscopic identification of pollen morphological phenotypes has been the traditional method used to identify and quantify pollen collected by air monitoring stations worldwide. Although this method has enabled a semi-standardized approach for the assessment of pollen exposure, limitations including labor intensiveness, required expertise, examiner bias, and the inability to differentiate species, genera, and in some cases families have limited data derived from the these stations. Recent advances in chemical, biochemical and molecular detection methods have provided standardized alternatives to this microscopic approach. In this review, we examine the applicability of alternative methodologies, in particular nucleic acid based assays involving the quantitative polymerase chain reaction, for the standardized detection of airborne pollen. PMID:22342607

  13. Isomers/enantiomers of perfluorocarboxylic acids: Method development and detection in environmental samples

    EPA Science Inventory

    Perfluoroalkyl substances are globally distributed in both urban and remote settings, and routinely are detected in wildlife, humans, and the environment. One of the most prominent and routinely detected perfluoroalkyl substances is perfluorooctanoic acid (PFOA), which has been s...

  14. A liquid chromatography-mass spectrometric method for the detection of cyclic β-amino fatty acid lipopeptides.

    PubMed

    Urajová, Petra; Hájek, Jan; Wahlsten, Matti; Jokela, Jouni; Galica, Tomáš; Fewer, David P; Kust, Andreja; Zapomělová-Kozlíková, Eliška; Delawská, Kateřina; Sivonen, Kaarina; Kopecký, Jiří; Hrouzek, Pavel

    2016-03-18

    Bacterial lipopeptides, which contain β-amino fatty acids, are an abundant group of bacterial secondary metabolites exhibiting antifungal and/or cytotoxic properties. Here we have developed an LC-HRMS/MS method for the selective detection of β-amino fatty acid containing cyclic lipopeptides. The method was optimized using the lipopeptides iturin A and puwainaphycin F, which contain fatty acids of similar length but differ in the amino acid composition of the peptide cycle. Fragmentation energies of 10-55eV were used to obtain the amino acid composition of the peptide macrocycle. However, fragmentation energies of 90-130eV were used to obtain an intense fragment specific for the β-amino fatty acid (CnH2n+2N(+)). The method allowed the number of carbons and consequently the length of the β-amino fatty acid to be estimated. We identified 21 puwainaphycin variants differing in fatty acid chain in the crude extract of cyanobacterium Cylindrospermum alatosporum using this method. Analogously 11 iturin A variants were detected. The retention time of the lipopeptide variants showed a near perfect linear dependence (R(2)=0.9995) on the length of the fatty acid chain in linear separation gradient which simplified the detection of minor variants. We used the method to screen 240 cyanobacterial strains and identified lipopeptides from 8 strains. The HPLC-HRMS/MS method developed here provides a rapid and easy way to detecting novel variants of cyclic lipopeptides. PMID:26893022

  15. A novel method for the detection of acidity in ice cores

    NASA Astrophysics Data System (ADS)

    Kjær, Helle Astrid; Vallelonga, Paul; Svensson, Anders

    2014-05-01

    The pH of polar ice is important for the stability and mobility of impurities in ice cores and can be strongly influenced by volcanic eruptions or anthropogenic emissions. We present a simple optical method for continuous determination of acidity in ice cores based on the absorption spectroscopy of two common pH-indicator dyes, bromophenol blue and chlorophenol red. The method does not require calibration with CO2 and is simpler than existing continuous flow analysis (CFA) methods for pH determination in ice cores, offering a 10-90% peak response time of 45s and a combined uncertainty of 9%. The method has been applied to sections of Greenland firn and Antarctic ice and compared to standard techniques such as Electrical Conductivity Measurements (ECM), conducted on the solid ice, and electrolytic conductivity of melted ice samples. The acidity as detected in the Greenland NEGIS firn core (75.38N, 35.56W), show an increasing trend up to the 1970's that can be explained by deposition of anthropogenic SO42- and NOX. The seasonal variability show highest acidity in winter (1900-1950 AD), but shifts towards spring for the period 1950-2000 AD. Conductivity and pH are found to be highly correlated in the Greenland NEGIS firn core with all signals greater than 3σ variability being related to either volcanic eruptions or forest fire activity. The method is ideal for finding the volcanic spikes in the firn than conventional ECM and DEP, which require density corrections in firn. In contrast to the NEGIS site, the Antarctic Roosevelt Island ice core (79.36S, 161.71W) features an anti-correlation between conductivity and pH, most likely due to the influence of marine salts.

  16. 78 FR 16513 - Application of Advances in Nucleic Acid and Protein Based Detection Methods to Multiplex...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ... Detection Methods to Multiplex Detection of Transfusion-Transmissible Agents and Blood Cell Antigens in...- Transmissible Agents and Blood Cell Antigens in Blood Donations.'' The purpose of this public workshop is to... and blood cell antigen typing. The public workshop has been planned in partnership with the...

  17. A Reliable and Inexpensive Method of Nucleic Acid Extraction for the PCR-Based Detection of Diverse Plant Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A reliable extraction method is described for the preparation of total nucleic acids from several plant genera for subsequent detection of plant pathogens by PCR-based techniques. By the combined use of a modified CTAB (cetyltrimethylammonium bromide) extraction protocol and a semi-automatic homogen...

  18. Method for the detection of specific nucleic acid sequences by polymerase nucleotide incorporation

    DOEpatents

    Castro, Alonso

    2004-06-01

    A method for rapid and efficient detection of a target DNA or RNA sequence is provided. A primer having a 3'-hydroxyl group at one end and having a sequence of nucleotides sufficiently homologous with an identifying sequence of nucleotides in the target DNA is selected. The primer is hybridized to the identifying sequence of nucleotides on the DNA or RNA sequence and a reporter molecule is synthesized on the target sequence by progressively binding complementary nucleotides to the primer, where the complementary nucleotides include nucleotides labeled with a fluorophore. Fluorescence emitted by fluorophores on single reporter molecules is detected to identify the target DNA or RNA sequence.

  19. Development of magnetic resonance imaging based detection methods for beta amyloids via sialic acid-functionalized magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kouyoumdjian, Hovig

    The development of a non-invasive method for the detection of Alzheimer's disease is of high current interest, which can be critical in early diagnosis and in guiding preventive treatment of the disease. The aggregates of beta amyloids are a pathological hallmark of Alzheimer's disease. Carbohydrates such as sialic acid terminated gangliosides have been shown to play significant roles in initiation of amyloid aggregation. Herein, we report a biomimetic approach using sialic acid coated iron oxide superparamagnetic nanoparticles for in vitro detection in addition to the assessment of the in vivo mouse-BBB (Blood brain barrier) crossing of the BSA (bovine serum albumin)-modified ones. The sialic acid functionalized dextran nanoparticles were shown to bind with beta amyloids through several techniques including ELISA (enzyme linked immunosorbent assay), MRI (magnetic resonance imaging), TEM (transmission electron microscopy), gel electrophoresis and tyrosine fluorescence assay. The superparamagnetic nature of the nanoparticles allowed easy detection of the beta amyloids in mouse brains in both in vitro and ex vivo model by magnetic resonance imaging. Furthermore, the sialic acid nanoparticles greatly reduced beta amyloid induced cytotoxicity to SH-SY5Y neuroblastoma cells, highlighting the potential of the glyconanoparticles for detection and imaging of beta amyloids. Sialic acid functionalized BSA (bovine serum albumin) nanoparticles also showed significant binding to beta amyloids, through ELISA and ex vivo mouse brain MRI experiments. Alternatively, the BBB crossing was demonstrated by several techniques such as confocal microscopy, endocytosis, exocytosis assays and were affirmed by nanoparticles transcytosis assays through bEnd.3 endothelial cells. Finally, the BBB crossing was confirmed by analyzing the MRI signal of nanoparticle-injected CD-1 mice.

  20. AN HPLC METHOD WITH UV DETECTION, PH CONTROL, AND REDUCTIVE ASCORBIC ACID FOR CYANURIC ACID ANALYSIS IN WATER

    EPA Science Inventory

    Every year over 250 million pounds of cyanuric acid (CA) and chloroisocyanurates are produced industrially. These compounds are standard ingredients in formulations for household bleaches, industrial cleansers, dishwasher compounds, general sanitizers, and chlorine stabilizers. ...

  1. Comparative Evaluation of Commercially Available Manual and Automated Nucleic Acid Extraction Methods for Rotavirus RNA Detection in Stool

    PubMed Central

    Esona, Mathew D.; McDonald, Sharla; Kamili, Shifaq; Kerin, Tara; Gautam, Rashi; Bowen, Michael D.

    2015-01-01

    Rotaviruses are a major cause of viral gastroenteritis in children. For accurate and sensitive detection of rotavirus RNA from stool samples by reverse transcription-polymerase chain reaction (RT-PCR), the extraction process must be robust. However, some extraction methods may not remove the strong RT-PCR inhibitors known to be present in stool samples. The objective of this study was to evaluate and compare the performance of six extraction methods used commonly for extraction of rotavirus RNA from stool, which have never been formally evaluated: the MagNA Pure Compact, KingFisher Flex and NucliSENS® easyMAG® instruments, the NucliSENS® miniMAG® semi-automated system, and two manual purification kits, the QIAamp Viral RNA kit and a modified RNaid® kit. Using each method, total nucleic acid or RNA was extracted from eight rotavirus-positive stool samples with enzyme immunoassay optical density (EIA OD) values ranging from 0.176 to 3.098. Extracts prepared using the MagNA Pure Compact instrument yielded the most consistent results by qRT-PCR and conventional RT-PCR. When extracts prepared from a dilution series were extracted by the 6 methods and tested, rotavirus RNA was detected in all samples by qRT-PCR but by conventional RT-PCR testing, only the MagNA Pure Compact and KingFisher Flex extracts were positive in all cases. RT-PCR inhibitors were detected in extracts produced with the QIAamp Viral RNA Mini kit. The findings of this study should prove useful for selection of extraction methods to be incorporated into future rotavirus detection and genotyping protocols. PMID:24036075

  2. A validated RP-HPLC method for quantitative determination of related impurities of ursodeoxycholic acid (API) by refractive index detection.

    PubMed

    Peepliwal, Ashok; Bonde, C G; Bothara, K G

    2011-03-25

    An isocratic RP-HPLC method was developed and validated for quantitative determination of ursodeoxycholic acid (UDCA) and its related impurities. Considering the lower molecular absorptivity of UDCA, refractive index detector was used to detect the impurities on a Phenomenex Luna C(18), 150 mm × 4.6 mm, 5 μm column. The mobile phase was 0.1% acetic acid/methanol (30:70, v/v) and flow rate was 0.8 ml/min. The detector and column temperature was maintained at 40°C. The method is linear over a range of 0.25-3.5 μg/ml for all impurities and coefficient of correlation (r(2)) was ≥0.9945. The accuracy of method demonstrated at three levels in the range of 50-150% of the specification limit and recoveries were found to be in the range of 97.11-100.75%. The precision for all related impurities was below 3.5% R.S.D. The method was applied to commercial bulk drug sample for assay purpose. PMID:21095088

  3. An Optimized Analytical Method for the Simultaneous Detection of Iodoform, Iodoacetic Acid, and Other Trihalomethanes and Haloacetic Acids in Drinking Water

    PubMed Central

    Jiang, Songhui; Templeton, Michael R.; He, Gengsheng; Qu, Weidong

    2013-01-01

    An optimized method is presented using liquid-liquid extraction and derivatization for the extraction of iodoacetic acid (IAA) and other haloacetic acids (HAA9) and direct extraction of iodoform (IF) and other trihalomethanes (THM4) from drinking water, followed by detection by gas chromatography with electron capture detection (GC-ECD). A Doehlert experimental design was performed to determine the optimum conditions for the five most significant factors in the derivatization step: namely, the volume and concentration of acidic methanol (optimized values  = 15%, 1 mL), the volume and concentration of Na2SO4 solution (129 g/L, 8.5 mL), and the volume of saturated NaHCO3 solution (1 mL). Also, derivatization time and temperature were optimized by a two-variable Doehlert design, resulting in the following optimized parameters: an extraction time of 11 minutes for IF and THM4 and 14 minutes for IAA and HAA9; mass of anhydrous Na2SO4 of 4 g for IF and THM4 and 16 g for IAA and HAA9; derivatization time of 160 min and temperature at 40°C. Under optimal conditions, the optimized procedure achieves excellent linearity (R2 ranges 0.9990–0.9998), low detection limits (0.0008–0.2 µg/L), low quantification limits (0.008–0.4 µg/L), and good recovery (86.6%–106.3%). Intra- and inter-day precision were less than 8.9% and 8.8%, respectively. The method was validated by applying it to the analysis of raw, flocculated, settled, and finished waters collected from a water treatment plant in China. PMID:23613747

  4. Determination of rosmarinic acid in sage and borage leaves by high-performance liquid chromatography with different detection methods.

    PubMed

    Bandoniene, Donata; Murkovic, Michael; Venskutonis, Petras R

    2005-08-01

    Rosmarinic acid is separated and identified on the basis of high-performance liquid chromatography (HPLC)-UV-mass spectrometry data in 80% methanol in water extracts from the leaves of Salvia species (S. officinalis, S. glutinosa, S. aethiopis, S. sclarea, and Borago officinalis) as a dominant radical scavenger towards the 2,2'-diphenyl-1-picrylhydrazyl (DPPH*) stable radical in HPLC-DPPH* system. The content of rosmarinic acid in the plants is calibrated and quantitated from chromatograms obtained by UV detection at 280 nm. The concentration ranges from 13.3 to 47.3 mg of the phenolic acid per gram dried leaves of all plants is tested. S. glutinosa and S. sclarea have the highest concentration of rosmarinic acid. The amount of rosmarinic acid in borage leaves is similar compared with Salvia officinalis (15 mg/g). The HPLC-DPPH* system is calibrated for quantitative DPPH* scavenging assessment of rosmarinic acid. The results reveal excellent correlation (r2 = 0.98) between the rosmarinic acid concentration and antiradical activity. PMID:16176651

  5. Fluorescence in situ Hybridization method using Peptide Nucleic Acid probes for rapid detection of Lactobacillus and Gardnerella spp.

    PubMed Central

    2013-01-01

    Background Bacterial vaginosis (BV) is a common vaginal infection occurring in women of reproductive age. It is widely accepted that the microbial switch from normal microflora to BV is characterized by a decrease in vaginal colonization by Lactobacillus species together with an increase of Gardnerella vaginalis and other anaerobes. Our goal was to develop and optimize a novel Peptide Nucleic Acid (PNA) Fluorescence in situ Hybridization assay (PNA FISH) for the detection of Lactobacillus spp. and G. vaginalis in mixed samples. Results Therefore, we evaluated and validated two specific PNA probes by using 36 representative Lactobacillus strains, 22 representative G. vaginalis strains and 27 other taxonomically related or pathogenic bacterial strains commonly found in vaginal samples. The probes were also tested at different concentrations of G. vaginalis and Lactobacillus species in vitro, in the presence of a HeLa cell line. Specificity and sensitivity of the PNA probes were found to be 98.0% (95% confidence interval (CI), from 87.8 to 99.9%) and 100% (95% CI, from 88.0 to 100.0%), for Lactobacillus spp.; and 100% (95% CI, from 92.8 to 100%) and 100% (95% CI, from 81.5 to 100.0%) for G. vaginalis. Moreover, the probes were evaluated in mixed samples mimicking women with BV or normal vaginal microflora, demonstrating efficiency and applicability of our PNA FISH. Conclusions This quick method accurately detects Lactobacillus spp. and G. vaginalis species in mixed samples, thus enabling efficient evaluation of the two bacterial groups, most frequently encountered in the vagina. PMID:23586331

  6. Okadaic acid meet and greet: an insight into detection methods, response strategies and genotoxic effects in marine invertebrates.

    PubMed

    Prego-Faraldo, María Verónica; Valdiglesias, Vanessa; Méndez, Josefina; Eirín-López, José M

    2013-08-01

    Harmful Algal Blooms (HABs) constitute one of the most important sources of contamination in the oceans, producing high concentrations of potentially harmful biotoxins that are accumulated across the food chains. One such biotoxin, Okadaic Acid (OA), is produced by marine dinoflagellates and subsequently accumulated within the tissues of filtering marine organisms feeding on HABs, rapidly spreading to their predators in the food chain and eventually reaching human consumers causing Diarrhetic Shellfish Poisoning (DSP) syndrome. While numerous studies have thoroughly evaluated the effects of OA in mammals, the attention drawn to marine organisms in this regard has been scarce, even though they constitute primary targets for this biotoxin. With this in mind, the present work aimed to provide a timely and comprehensive insight into the current literature on the effect of OA in marine invertebrates, along with the strategies developed by these organisms to respond to its toxic effect together with the most important methods and techniques used for OA detection and evaluation. PMID:23939476

  7. Method for detecting biological toxins

    SciTech Connect

    Ligler, F.S.; Campbell, J.R.

    1992-01-01

    Biological toxins are indirectly detected by using polymerase chain reaction to amplify unique nucleic acid sequences coding for the toxins or enzymes unique to toxin synthesis. Buffer, primers coding for the unique nucleic acid sequences and an amplifying enzyme are added to a sample suspected of containing the toxin. The mixture is then cycled thermally to exponentially amplify any of these unique nucleic acid sequences present in the sample. The amplified sequences can be detected by various means, including fluorescence. Detection of the amplified sequences is indicative of the presence of toxin in the original sample. By using more than one set of labeled primers, the method can be used to simultaneously detect several toxins in a sample.

  8. Ambient formic acid in southern California air: A comparison of two methods, Fourier transform infrared spectroscopy and alkaline trap-liquid chromatography with UV detection

    SciTech Connect

    Grosjean, D. ); Tuazon, E.C. ); Fujita, E. )

    1990-01-01

    Formic acid is an ubiquitous component of urban smog. Sources of formic acid in urban air include direct emissions from vehicles and in situ reaction of ozone with olefins. Ambient levels of formic acid in southern California air were first measured some 15 years ago by Hanst et al. using long-path Fourier transform infrared spectroscopy (FTIR). All subsequent studies of formic acid in the Los Angeles area have involved the use of two methods, either FTIR or collection on alkaline traps followed by gas chromatography, ion chromatography, or liquid chromatography analysis with UV detection, ATLC-UV. The Carbon Species Methods Comparison Study (CSMCS), a multilaboratory air quality study carried out in August 1986 at a southern California smog receptor site, provided an opportunity for direct field comparison of the FTIR and alkaline trap methods. The results of the comparison are presented in this brief report.

  9. A method for the determination of the hepatic enzyme activity catalyzing bile acid acyl glucuronide formation by high-performance liquid chromatography with pulsed amperometric detection.

    PubMed

    Ikegawa, S; Oohashi, J; Murao, N; Goto, J

    2000-05-01

    A method for the determination of the activity of hepatic glucuronyltransferase catalyzing formation of bile acid 24-glucuronides using high-performance liquid chromatography (HPLC) with pulsed amperometric detection (PAD) has been developed. Bile acid 24-glucuronides were simultaneously separated on a semimicrobore column, Capcell Pak C18UG120, using 20 mM ammonium phosphate (pH 6.0)-acetonitrile (27:10 and 16:10) as the mobile phase in the stepwise gradient elution mode. A 1 M potassium hydroxide solution for the hydrolysis of the 24-glucuronides, which liberates the corresponding bile acids and glucuronic acid, was mixed with the mobile phase in a post-column mode, and the resulting eluant was heated at 90 degrees C, the 24-glucuronides being monitored using a pulsed amperometric detector; the limit of detection was 10 ng. The proposed method was applied to the determination of the hepatic enzyme activity catalyzing bile acid 24-glucuronide formation and the result exhibited the efficient 24-glucuronide formation of the monohydroxylated bile acid, lithocholic acid. PMID:10850616

  10. Sulfenic acid chemistry, detection and cellular lifetime☆

    PubMed Central

    Gupta, Vinayak; Carroll, Kate S.

    2014-01-01

    Background Reactive oxygen species-mediated cysteine sulfenic acid modification has emerged as an important regulatory mechanism in cell signaling. The stability of sulfenic acid in proteins is dictated by the local microenvironment and ability of antioxidants to reduce this modification. Several techniques for detecting this cysteine modification have been developed, including direct and in situ methods. Scope of review This review presents a historical discussion of sulfenic acid chemistry and highlights key examples of this modification in proteins. A comprehensive survey of available detection techniques with advantages and limitations is discussed. Finally, issues pertaining to rates of sulfenic acid formation, reduction, and chemical trapping methods are also covered. Major conclusions Early chemical models of sulfenic acid yielded important insights into the unique reactivity of this species. Subsequent pioneering studies led to the characterization of sulfenic acid formation in proteins. In parallel, the discovery of oxidant-mediated cell signaling pathways and pathological oxidative stress has led to significant interest in methods to detect these modifications. Advanced methods allow for direct chemical trapping of protein sulfenic acids directly in cells and tissues. At the same time, many sulfenic acids are short-lived and the reactivity of current probes must be improved to sample these species, while at the same time, preserving their chemical selectivity. Inhibitors with binding scaffolds can be rationally designed to target sulfenic acid modifications in specific proteins. General significance Ever increasing roles for protein sulfenic acids have been uncovered in physiology and pathology. A more complete understanding of sulfenic acid-mediated regulatory mechanisms will continue to require rigorous and new chemical insights. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and

  11. Solid Phase Micro-extraction (SPME) with In Situ Transesterification: An Easy Method for the Detection of Non-volatile Fatty Acid Derivatives on the Insect Cuticle.

    PubMed

    Kühbandner, Stephan; Ruther, Joachim

    2015-06-01

    Triacylglycerides (TAGs) and other non-volatile fatty acid derivatives (NFADs) occur in large amounts in the internal tissues of insects, but their presence on the insect cuticle is controversially discussed. Most studies investigating cuticular lipids of insects involve solvent extraction, which implies the risk of extracting lipids from internal tissues. Here, we present a new method that overcomes this problem. The method employs solid phase micro-extraction (SPME) to sample NFADs by rubbing the SPME fiber over the insect cuticle. Subsequently, the sampled NFADs are transesterified in situ with trimethyl sulfonium hydroxide (TMSH) into more volatile fatty acid methyl esters (FAMEs), which can be analyzed by standard GC/MS. We performed two types of control experiments to enable significant conclusions: (1) to rule out contamination of the GC/MS system with NFADs, and (2) to exclude the presence of free fatty acids on the insect cuticle, which would also furnish FAMEs after TMSH treatment, and thus might simulate the presence of NFADs. In combination with these two essential control experiments, the described SPME technique can be used to detect TAGs and/or other NFADs on the insect cuticle. We analyzed six insect species from four insect orders with our method and compared the results with conventional solvent extraction followed by ex situ transesterification. Several fatty acids typically found as constituents of TAGs were detected by the SPME method on the cuticle of all species analyzed. A comparison of the two methods revealed differences in the fatty acid compositions of the samples. Saturated fatty acids showed by trend higher relative abundances when sampled with the SPME method, while several minor FAMEs were detected only in the solvent extracts. Our study suggests that TAGs and maybe other NFADs are far more common on the insect cuticle than usually thought. PMID:26025161

  12. Limits of detections for the determination of mono- and dicarboxylic acids using gas and liquid chromatographic methods coupled with mass spectrometry

    PubMed Central

    Št’ávová, Jana; Beránek, Josef; Nelson, Eric P.; Diep, Bonnie A.; Kubátová, Alena

    2011-01-01

    The chromatographic separation and instrumental limits of detection (LODs) were obtained for a broad range of C1-C18 monocarboxylic (MCAs) and C2-C14 dicarboxylic acids (DCAs) employing either chemical derivatization followed by gas chromatography-mass spectrometry and flame ionization detection (GC-MS/FID) or direct analysis with liquid chromatography high resolution MS and tandem MS (LC-MS). Suitability, efficiency and stability of reaction products for several derivatization agents used for esterification (BF3/butanol), and trimethysilylation, including trimethylsilyl-N-N-dimethylcarbamate (TMSDMC) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) were evaluated. The lowest limits of detection for the majority of compounds below 10 pg (with the exception of acetic acid) were obtained for derivatization with BF3/butanol followed by GC-MS in the total ion current (TIC) mode. Further improvements were achieved when applying either selected ion monitoring (SIM), which decreased the LODs to 1–4 pg or a combination of SIM and TIC (SITI) (2–5 pg). GC-FID provided LODs comparable to those obtained by GC-MS TIC. Both trimethylsilylation (followed by GC-MS) and direct LC-MS/MS analysis yielded LODs of 5– 40 pg for most of the acids. For volatile acids the LODs were higher, e.g., 25 and 590 ng for TMSDMC and BSTFA derivatized formic acid, respectively whereas the LC-MS methods did not allow for the analysis of formic acid at all. PMID:21185238

  13. Discovery of the antibiotic phosacetamycin via a new mass spectrometry-based method for phosphonic acid detection

    PubMed Central

    Evans, Bradley S.; Zhao, Changming; Gao, Jiangtao; Evans, Courtney M.; Ju, Kou-San; Doroghazi, James R.; van der Donk, Wilfred A.; Kelleher, Neil L.; Metcalf, William W.

    2013-01-01

    Naturally occurring phosphonates such as phosphinothricin (Glufosinate, a commercially used herbicide) and fosfomycin (Monurol, a clinically used antibiotic) have proved to be potent and useful biocides. Yet this class of natural products is still an under explored family of secondary metabolites. Discovery of the biosynthetic pathways responsible for the production of these compounds has been simplified by using gene based screening approaches, but detection and identification of the natural products the genes produce has been hampered by a lack of high-throughput methods for screening potential producers under various culture conditions. Here we present an efficient mass-spectrometric method for the selective detection of natural products containing phosphonate and phosphinate functional groups. We have used this method to identify a new phosphonate metabolite, phosacetamycin, whose structure, biological activity, and biosynthetic gene cluster are reported. PMID:23474169

  14. Method for isolating nucleic acids

    DOEpatents

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  15. A HPLC-fluorescence detection method for determination of phosphatidic acid phosphohydrolase activity: application in human myocardium.

    PubMed

    Burgdorf, Christof; Prey, Antje; Richardt, Gert; Kurz, Thomas

    2008-03-15

    Phosphatidic acid phosphohydrolase (PAP) catalyzes the dephosphorylation of phosphatidic acid (PA) to diacylglycerol, the second messenger responsible for activation of protein kinase C. Despite the crucial role of PAP lipid signaling, there are no data on PAP signaling function in the human heart. Here we present a nonradioactive assay for the investigation of PAP activity in human myocardium using a fluorescent derivative of PA, 2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexadecanoyl-sn-glycero-3-phosphate (BODIPY-PA), as substrate in an in vitro PAP-catalyzed reaction. Unreacted BODIPY-PA was resolved from the PAP products by a binary gradient HPLC system and BODIPY-diacylglycerol was detected by fluorimetry. The reaction proceeded at a linear rate for up to 60 min and increased linearly with increasing amounts of cardiac protein in a range of 0.25 to 8.0 microg. This assay proved to be sensitive for accurate quantitation of total PAP activity, PAP-1 activity, and PAP-2 activity in human atrial tissue and right ventricular endomyocardial biopsies. Total PAP activity was approximately fourfold higher in ventricular myocardium than in atrial tissue. There was negligible PAP-1 activity in atrial myocardium compared with ventricular myocardium, indicating regional differences in activities and distribution pattern of PAP-1 and PAP-2 in the human heart. PMID:18023403

  16. Development of a Quantitative GC-MS Method for the Detection of Cyclopropane Fatty Acids in Cheese as New Molecular Markers for Parmigiano Reggiano Authentication.

    PubMed

    Caligiani, Augusta; Nocetti, Marco; Lolli, Veronica; Marseglia, Angela; Palla, Gerardo

    2016-05-25

    Cyclopropane fatty acids (CPFA), as lactobacillic acid and dihydrosterculic acid, are components of bacterial membranes and have been recently detected in milk and in dairy products from cows fed with corn silage. In this paper, a specific quantitative gas chromatography-mass spectrometry (GC-MS) method for the detection of CPFA in cheeses was developed, and the quality parameters of the method (limit of detection, limit of quantitation, and intralaboratory precision) were assessed. Limit of detection and quantitation of CPFA were, respectively, 60 and 200 mg/kg of cheese fat, and the intralaboratory precision, determined on three concentration levels, satisfied the Horwitz equation. This method was applied to 304 samples of PDO cheeses of certified origin, including Parmigiano Reggiano (Italy), Grana Padano (Italy), Fontina (Italy), Comté (France), and Gruyère (Switzerland). Results showed that CPFA were absent in all of the cheeses whose Production Specification Rules expressly forbid the use of silages (Parmigiano Reggiano, Fontina, Comté, and Gruyère). CPFA were instead present in variable concentrations (300-830 mg/kg of fat) in all of the samples of Grana Padano cheese (silages admitted). A mix of grated Parmigiano Reggiano and Grana Padano was also prepared, showing that the method is able to detect the counterfeiting of Parmigiano Reggiano with other cheeses up to 10-20% Grana Padano content. These results support the hypothesis that CPFA can be used as a marker of silage feedings for cheeses, and the data reported can be considered a first attempt to create a database for CPFA presence in PDO cheeses. PMID:27133588

  17. Multigrid contact detection method

    NASA Astrophysics Data System (ADS)

    He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

    2007-03-01

    Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N) . Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved.

  18. Use of Dimedone-Based Chemical Probes for Sulfenic Acid Detection: Methods to Visualize and Identify Labeled Proteins

    PubMed Central

    Nelson, Kimberly J.; Klomsiri, Chananat; Codreanu, Simona G.; Soito, Laura; Liebler, Daniel C.; Rogers, LeAnn C.; Daniel, Larry W.; Poole, Leslie B.

    2013-01-01

    Reversible thiol modification is a major component of the modulation of cell-signaling pathways by reactive oxygen species. Hydrogen peroxide, peroxynitrite, or lipid hydroperoxides are all able to oxidize cysteines to form cysteine sulfenic acids; this reactive intermediate can be directly reduced to thiol by cellular reductants such as thioredoxin or further participate in disulfide bond formation with glutathione or cysteine residues in the same or another protein. To identify the direct protein targets of cysteine modification and the conditions under which they are oxidized, a series of dimedone-based reagents linked to affinity or fluorescent tags have been developed that specifically alkylate and trap cysteine sulfenic acids. In this chapter, we provide detailed methods using one of our biotin-tagged reagents, DCP-Bio1, to identify and monitor proteins that are oxidized in vitro and in vivo. Using streptavidin-linked agarose beads, this biotin-linked reagent can be used to affinity capture labeled proteins. Stringent washing of the beads prior to elution minimizes the contamination of the enriched material with unlabeled proteins through coimmunoprecipitation or nonspecific binding. In particular, we suggest including DTT in one of the washes to remove proteins covalently linked to biotinylated proteins through a disulfide bond, except in cases where these linked proteins are of interest. We also provide methods for targeted approaches monitoring cysteine oxidation in individual proteins, global approaches to follow total cysteine oxidation in the cell, and guidelines for proteomic analyses to identify novel proteins with redox sensitive cysteines. PMID:20513473

  19. Comparison and validation of 2 analytical methods for the determination of free fatty acids in dairy products by gas chromatography with flame ionization detection.

    PubMed

    Mannion, David T; Furey, Ambrose; Kilcawley, Kieran N

    2016-07-01

    Accurate quantification of free fatty acids (FFA) in dairy products is important for quality control, nutritional, antimicrobial, authenticity, legislative, and flavor purposes. In this study, the performance of 2 widely used gas chromatographic flame ionization detection methods for determination of FFA in dairy products differing in lipid content and degree of lipolysis were evaluated. We used a direct on-column approach where the isolated FFA extract was injected directly and a derivatization approach where the FFA were esterified in the injector to methyl esters using tetramethylammonium hydroxide as a catalyst. A comprehensive validation was undertaken to establish method linearity, limits of detection, limits of quantification, accuracy, and precision. Linear calibrations of 3 to 700mg/L (R(2)>0.999) and 20 to 700mg/L (R(2)>0.997), and limits of detection and limits of quantification of 0.7 and 3mg/L and 5 and 20mg/L were obtained for the direct injection on-column and the derivatization method, respectively. Intraday precision of 1.5 to 7.2% was obtained for both methods. The direct injection on-column method had the lower levels of limits of detection and quantification, because FFA are directly injected onto the GC as opposed to the split injection used in the derivatization method. However, the direct injection on-column method experienced accumulative column phase deterioration and irreversible FFA absorption because of the acidic nature of the injection extract, which adversely affected method robustness and the quantification of some longer chain FFA. The derivatization method experienced issues with quantification of butyric acid at low concentrations because of coelution with the injection solvent peak, loss of polyunsaturated FFA due to degradation by tetramethylammonium hydroxide, and the periodic emergence of by-product peaks of the tetramethylammonium hydroxide reaction that interfered with the quantification of some short-chain FFA. The

  20. Development of high performance liquid chromatography-ultraviolet detection method for screening mebendazole, clorsulon, diaveridine, and tolfenamic acid in animal-based food samples.

    PubMed

    Kang, Yun Pyo; Yu, Jin; Huh, Yoonyoung; Oh, Jae Ho; Kwon, Chan Hyeok; Lee, Seul Ji; Ee, Ji Won; Kim, Geun Tae; Lee, Jin Gyun; Lee, Jeongmi; Park, Jeong Hill; Kim, You-Sun; Kwon, Sung Won

    2014-03-01

    This study focused on the detection and validation of the residues of the four veterinary drugs, mebendazole, clorsulon, diaveridine, and tolfenamic acid, using high performance liquid chromatography (HPLC) and an ultraviolet (UV) detector. Utilizing C18 column as a stationary phase and applying appropriate mobile phases to each analysis according to the properties of the analytes, target compounds in food samples were successfully detected and separated within 15-50 min. Additionally, in order to optimize detection, liquid-liquid extraction (LLE) and purification steps were established to minimize the endogenous peaks and their interferences. The method was validated through testing of linearity, accuracy, precision, the limit of detection (LOD) and the limit of quantification (LOQ). The LOQ levels of the four drugs were lower than the maximum residual limit, and the coefficient of determination (R(2) ) was over 0.99. The recovery results ranged from 82.3-105.2%, 79.3-83.3%, 79.4-86.0%, and 81.7-88.5% with relative standard deviations lower than 20% for mebendazole, clorsulon, diaveridine, and tolfenamic acid, respectively, corresponding to the CODEX guideline. This proposed method reduces costs and enables easier application in rural or remote areas where testing facilities or instruments often are unavailable. PMID:23576386

  1. Methods of Melanoma Detection.

    PubMed

    Leachman, Sancy A; Cassidy, Pamela B; Chen, Suephy C; Curiel, Clara; Geller, Alan; Gareau, Daniel; Pellacani, Giovanni; Grichnik, James M; Malvehy, Josep; North, Jeffrey; Jacques, Steven L; Petrie, Tracy; Puig, Susana; Swetter, Susan M; Tofte, Susan; Weinstock, Martin A

    2016-01-01

    Detection and removal of melanoma, before it has metastasized, dramatically improves prognosis and survival. The purpose of this chapter is to (1) summarize current methods of melanoma detection and (2) review state-of-the-art detection methods and technologies that have the potential to reduce melanoma mortality. Current strategies for the detection of melanoma range from population-based educational campaigns and screening to the use of algorithm-driven imaging technologies and performance of assays that identify markers of transformation. This chapter will begin by describing state-of-the-art methods for educating and increasing awareness of at-risk individuals and for performing comprehensive screening examinations. Standard and advanced photographic methods designed to improve reliability and reproducibility of the clinical examination will also be reviewed. Devices that magnify and/or enhance malignant features of individual melanocytic lesions (and algorithms that are available to interpret the results obtained from these devices) will be compared and contrasted. In vivo confocal microscopy and other cellular-level in vivo technologies will be compared to traditional tissue biopsy, and the role of a noninvasive "optical biopsy" in the clinical setting will be discussed. Finally, cellular and molecular methods that have been applied to the diagnosis of melanoma, such as comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH), and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), will be discussed. PMID:26601859

  2. Methods of Endotoxin Detection.

    PubMed

    Su, Wenqiong; Ding, Xianting

    2015-08-01

    Endotoxin, present in the outer membrane of all gram-negative bacteria, can pose serious risks to human health, from irreversible shock to death. Therefore, it is essential to develop sensitive, accurate, and rapid methods for its detection. The rabbit pyrogen test is the first standard technique for endotoxin detection and, nowadays, has been replaced by the Limulus Amoebocyte Lysate test, which is the most popular detection technique for endotoxin. With in-depth understanding of endotoxin, biosensors based on endotoxin-sensing components are promising alternatives to pursue in developing low-cost, easy-operation, and fast-response endotoxin detection techniques. This article summarizes the recent advances of endotoxin detection methods with a particular emphasis on optical and electrochemical biosensors based on various sensing elements ranging from nature biomolecules to artificial materials. As the research and technological revolution continues, the highly integrated and miniaturized commercial devices for sensitively and reliably detecting endotoxin will provide a wide range of applications in people's daily life. PMID:25720597

  3. Methods for Doping Detection.

    PubMed

    Ponzetto, Federico; Giraud, Sylvain; Leuenberger, Nicolas; Boccard, Julien; Nicoli, Raul; Baume, Norbert; Rudaz, Serge; Saugy, Martial

    2016-01-01

    Over the past few years, the World Anti-Doping Agency (WADA) has focused its efforts on detecting not only small prohibited molecules, but also larger endogenous molecules such as hormones, in the view of implementing an endocrinological module in the Athlete Biological Passport (ABP). In this chapter, the detection of two major types of hormones used for doping, growth hormone (GH) and endogenous anabolic androgenic steroids (EAASs), will be discussed: a brief historical background followed by a description of state-of-the-art methods applied by accredited anti-doping laboratories will be provided and then current research trends outlined. In addition, microRNAs (miRNAs) will also be presented as a new class of biomarkers for doping detection. PMID:27348309

  4. Error detection method

    DOEpatents

    Olson, Eric J.

    2013-06-11

    An apparatus, program product, and method that run an algorithm on a hardware based processor, generate a hardware error as a result of running the algorithm, generate an algorithm output for the algorithm, compare the algorithm output to another output for the algorithm, and detect the hardware error from the comparison. The algorithm is designed to cause the hardware based processor to heat to a degree that increases the likelihood of hardware errors to manifest, and the hardware error is observable in the algorithm output. As such, electronic components may be sufficiently heated and/or sufficiently stressed to create better conditions for generating hardware errors, and the output of the algorithm may be compared at the end of the run to detect a hardware error that occurred anywhere during the run that may otherwise not be detected by traditional methodologies (e.g., due to cooling, insufficient heat and/or stress, etc.).

  5. Studies in lipid histochemistry. XIII. The OPA (osmiumtetroxide-periodic acid-alpha-naphthylamine) method for the detection of apolar lipids.

    PubMed

    Elleder, M

    1975-09-29

    A new procedure for the detection of apolar lipids is described. It is a modification of the OTAN method (Adams, 1959) using periodic acid which oxidatively removes lower osmium derivatives from polar sites only, leaving those in apolar lipids intact and demonstrable with alpha-naphthylamine. Control steps for the exclusion of the possible interference of some less polar complex lipids and of lipopigments are described. The described technic is superior to the conventionally used sudan dyes due partly to the fact that only aqueous solutions are employed thus excluding any extraction of lipids, partly to the more distinct coloration. PMID:171245

  6. Method for detecting biomolecules

    DOEpatents

    Huo, Qisheng; Liu, Jun

    2008-08-12

    A method for detecting and measuring the concentration of biomolecules in solution, utilizing a conducting electrode in contact with a solution containing target biomolecules, with a film with controllable pore size distribution characteristics applied to at least one surface of the conducting electrode. The film is functionalized with probe molecules that chemically interact with the target biomolecules at the film surface, blocking indicator molecules present in solution from diffusing from the solution to the electrode, thereby changing the electrochemical response of the electrode

  7. Detection of Escherichia coli O157 by Peptide Nucleic Acid Fluorescence In Situ Hybridization (PNA-FISH) and Comparison to a Standard Culture Method

    PubMed Central

    Almeida, C.; Sousa, J. M.; Rocha, R.; Cerqueira, L.; Fanning, S.; Azevedo, N. F.

    2013-01-01

    Despite the emergence of non-O157 Shiga toxin-producing Escherichia coli (STEC) infections, E. coli serotype O157 is still the most commonly identified STEC in the world. It causes high morbidity and mortality and has been responsible for a number of outbreaks in many parts of the world. Various methods have been developed to detect this particular serotype, but standard bacteriological methods remain the gold standard. Here, we propose a new peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) method for the rapid detection of E. coli O157. Testing on 54 representative strains showed that the PNA probe is highly sensitive and specific to E. coli O157. The method then was optimized for detection in food samples. Ground beef and unpasteurized milk samples were artificially contaminated with E. coli O157 concentrations ranging from 1 × 10−2 to 1 × 102 CFU per 25 g or ml of food. Samples were then preenriched and analyzed by both the traditional bacteriological method (ISO 16654:2001) and PNA-FISH. The PNA-FISH method performed well in both types of food matrices with a detection limit of 1 CFU/25 g or ml of food samples. Tests on 60 food samples have shown a specificity value of 100% (95% confidence interval [CI], 82.83 to 100), a sensitivity of 97.22% (95% CI, 83.79 to 99.85%), and an accuracy of 98.33% (CI 95%, 83.41 to 99.91%). Results indicate that PNA-FISH performed as well as the traditional culture methods and can reduce the diagnosis time to 1 day. PMID:23934486

  8. Merging a sensitive capillary electrophoresis-ultraviolet detection method with chemometric exploratory data analysis for the determination of phenolic acids and subsequent characterization of avocado fruit.

    PubMed

    Hurtado-Fernández, Elena; Contreras-Gutiérrez, Paulina K; Cuadros-Rodríguez, Luis; Carrasco-Pancorbo, Alegría; Fernández-Gutiérrez, Alberto

    2013-12-15

    Herein we present the development of a powerful CE-UV method able to detect and quantify an important number of phenolic acids in 13 varieties of avocado fruits at 2 ripening stages. All the variables involved in CE separation were exhaustively optimized and the best results were obtained with a capillary of 50 μm i.d. × 50 cm effective length, sodium tetraborate 40 mM at a pH of 9.4, 30 kV, 25 °C, 10s of hydrodynamic injection (0.5 psi) and UV detection at 254 nm. This optimal methodology was fully validated and then applied to different avocado samples. The number of phenolic acids determined varied from 8 to 14 compounds; in general, they were in concentrations ranging from 0.13 ppm to 3.82 ppm, except p-coumaric, benzoic and protocatechuic acids, which were found at higher concentrations. Principal component analysis (PCA) was applied to highlight the differences between varieties and ripening degrees, looking for the most influential analytes. PMID:23993512

  9. Optimized culturing and nucleic acid-based methods for the detection of Salmonella enterica in poultry environments.

    PubMed

    Schultz, J; Jarquin, R; Ricke, S C; Hanning, I

    2012-11-01

    The main objective of this trial was to set up a series of assays following quantified inoculation of Salmonella samples in 2 initial enrichment methods to ultimately determine the most effective and fastest detection method for recovery of Salmonella in a poultry environment matrix. Samples were randomly split into 2 different containers containing either buffered peptone water (BPW) + yeast extract, or tetrathionate broth (TT) with added iodine and Brilliant Green solution 0.1%. A frozen stock Salmonella culture was thawed and serially diluted 10-fold to inoculate 100 µL of the dilution into the enriched samples. The samples were incubated at 42 and 37°C, respectively, for 24 h and secondarily enriched in modified semi-solid Rappaport Vassiliadis (MSRV) incubated at 42°C. All samples then were reincubated under the same conditions. After secondary enrichment, the samples were streaked onto Chromogenic agar/ XLT4 bi-plates and incubated under the same conditions. After initial inoculation and each 24-h incubation, a portion of the enriched samples was analyzed using a real-time PCR assay. The results of this trial indicate that recovery of Salmonella in a culture-based assay may be enhanced by up to 3 logs by using the TT as the initial enrichment media compared with BPW. The incorporation of MSRV as a secondary cultural selective media after the TT gave the best recovery of Salmonella. These data indicate that considerable time can be saved by using TT as an initial media for Salmonella recovery. PMID:23091129

  10. RAPID AND SIMPLIFIED HPLC METHOD WITH UV DETECTION, PH CONTROL AND SELECTIVE DECHLORINATOR FOR CYANURIC ACID ANALYSIS IN WATER

    EPA Science Inventory

    Cyanuric acid (CA) and chloroisocyanurates are commonly used as standard ingredients in formulations for household bleaches, industrial cleansers, dishwasher compounds, general sanitizers, and chlorine stabilizers. They are very well known for preventing the photolytic decomposi...

  11. A sensitive GC-EIMS method for simultaneous detection and quantification of JWH-018 and JWH-073 carboxylic acid and hydroxy metabolites in urine.

    PubMed

    Paul, Buddha D; Bosy, Thomas

    2015-04-01

    Synthetic cannabinoids, including JWH-018 and JWH-073, belong to a class of aminoalkylindoles (AAIs) that are smoked to produce an effect similar to tetrahydrocannabinol. Compounds in this class are often collectively known as 'Spice'. After ingestion, these compounds are extensively metabolized to their hydroxy and carboxylic acid metabolites. During forensic analysis, detection of these metabolites in urine is an indication of past exposure to the parent compounds. The analytical process involved hydrolysis of conjugated metabolites by glucuronidase, solvent extraction, derivatization by trifluoroacetic anhydride and hexafluoroisopropanol and GC-EIMS detection. Identification of the unknown was based on the criteria of GC retention time within ±2% and mass spectral ion ratio within ±20% of that of a standard. Deuterated internal standards of the carboxylic acid metabolites were used for quantification. The acid (JWH-018-COOH, JWH-073-COOH) and hydroxy (JWH-018-OH, JWH-073-OH) metabolites were linear over the concentration range of 0.1-10 and 0.2-10 ng/mL, respectively, with a correlation coefficient-square, R(2) > 0.999 (N = 5). Extraction recoveries of the metabolites were within 79 and 87%. The method was applied to 17 urine specimens collected as part of a military law enforcement investigation. Nine of the specimens tested positive for one or more of the metabolites. When the procedure was extended to screen other AAI compounds, two of the specimens were found to contain JWH-210, JWH-250 (JWH-302 or JWH-201) and JWH-250 (C4 isomers). The GC-EIMS method presented here was found to be suitable for detecting JWH-018 and JWH-073 metabolites and other AAI compounds in urine. PMID:25691387

  12. Statistical methods for assays with limits of detection: Serum bile acid as a differentiator between patients with normal colons, adenomas, and colorectal cancer

    PubMed Central

    LaFleur, Bonnie; Lee, Wooin; Billhiemer, Dean; Lockhart, Craig; Liu, Junmei; Merchant, Nipun

    2011-01-01

    In analytic chemistry a detection limit (DL) is the lowest measurable amount of an analyte that can be distinguished from a blank; many biomedical measurement technologies exhibit this property. From a statistical perspective, these data present inferential challenges because instead of precise measures, one only has information that the value is somewhere between 0 and the DL (below detection limit, BDL). Substitution of BDL values, with 0 or the DL can lead to biased parameter estimates and a loss of statistical power. Statistical methods that make adjustments when dealing with these types of data, often called left-censored data, are available in many commercial statistical packages. Despite this availability, the use of these methods is still not widespread in biomedical literature. We have reviewed the statistical approaches of dealing with BDL values, and used simulations to examine the performance of the commonly used substitution methods and the most widely available statistical methods. We have illustrated these methods using a study undertaken at the Vanderbilt-Ingram Cancer Center, to examine the serum bile acid levels in patients with colorectal cancer and adenoma. We have found that the modern methods for BDL values identify disease-related differences that are often missed, with statistically naive approaches. PMID:21712958

  13. Detection of nucleic acids by multiple sequential invasive cleavages

    DOEpatents

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann D.

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of human cytomegalovirus nucleic acid in a sample.

  14. Detection of nucleic acids by multiple sequential invasive cleavages 02

    DOEpatents

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann D.

    2002-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of human cytomegalovirus nucleic acid in a sample.

  15. Detection of nucleic acids by multiple sequential invasive cleavages

    DOEpatents

    Hall, Jeff G; Lyamichev, Victor I; Mast, Andrea L; Brow, Mary Ann D

    2012-10-16

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of human cytomegalovirus nucleic acid in a sample.

  16. The Development of a Specific and Sensitive LC-MS-Based Method for the Detection and Quantification of Hydroperoxy- and Hydroxydocosahexaenoic Acids as a Tool for Lipidomic Analysis

    PubMed Central

    Derogis, Priscilla B. M. C.; Freitas, Florêncio P.; Marques, Anna S. F.; Cunha, Daniela; Appolinário, Patricia P.; de Paula, Fernando; Lourenço, Tiago C.; Murgu, Michael; Di Mascio, Paolo; Medeiros, Marisa H. G.; Miyamoto, Sayuri

    2013-01-01

    Docosahexaenoic acid (DHA) is an n-3 polyunsaturated fatty acid that is highly enriched in the brain, and the oxidation products of DHA are present or increased during neurodegenerative disease progression. The characterization of the oxidation products of DHA is critical to understanding the roles that these products play in the development of such diseases. In this study, we developed a sensitive and specific analytical tool for the detection and quantification of twelve major DHA hydroperoxide (HpDoHE) and hydroxide (HDoHE) isomers (isomers at positions 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19 and 20) in biological systems. In this study, HpDoHE were synthesized by photooxidation, and the corresponding hydroxides were obtained by reduction with NaBH4. The isolated isomers were characterized by LC-MS/MS, and unique and specific fragment ions were chosen to construct a selected reaction monitoring (SRM) method for the targeted quantitative analysis of each HpDoHE and HDoHE isomer. The detection limits for the LC-MS/MS-SRM assay were 1−670 pg for HpDoHE and 0.5−8.5 pg for HDoHE injected onto a column. Using this method, it was possible to detect the basal levels of HDoHE isomers in both rat plasma and brain samples. Therefore, the developed LC-MS/MS-SRM can be used as an important tool to identify and quantify the hydro(pero)xy derivatives of DHA in biological system and may be helpful for the oxidative lipidomic studies. PMID:24204871

  17. Waveguide disturbance detection method

    DOEpatents

    Korneev, Valeri A.; Nihei, Kurt T.; Myer, Larry R.

    2000-01-01

    A method for detection of a disturbance in a waveguide comprising transmitting a wavefield having symmetric and antisymmetric components from a horizontally and/or vertically polarized source and/or pressure source disposed symmetrically with respect to the longitudinal central axis of the waveguide at one end of the waveguide, recording the horizontal and/or vertical component or a pressure of the wavefield with a vertical array of receivers disposed at the opposite end of the waveguide, separating the wavenumber transform of the wavefield into the symmetric and antisymmetric components, integrating the symmetric and antisymmetric components over a broad frequency range, and comparing the magnitude of the symmetric components and the antisymmetric components to an expected magnitude for the symmetric components and the antisymmetric components for a waveguide of uniform thickness and properties thereby determining whether or not a disturbance is present inside the waveguide.

  18. Electrochemical-surface enhanced Raman spectroscopy (E-SERS) of uric acid: a potential rapid diagnostic method for early preeclampsia detection.

    PubMed

    Goodall, Barbara L; Robinson, Ashley M; Brosseau, Christa L

    2013-02-01

    An increased level of uric acid in urine and plasma is indicative of the development of preeclampsia, a hypertensive disorder that can occur during pregnancy. The preliminary steps towards developing a rapid tool for early diagnosis of preeclampsia using electrochemical SERS (E-SERS) for the detection of uric acid in urine are presented herein. Characterization of the uric acid species was completed using cyclic voltammetry, UV spectroscopy, Raman spectroscopy and electrochemical surface-enhanced Raman spectroscopy (E-SERS). E-SERS was capable of easily detecting uric acid directly at concentrations <1 mM in urine simulant, without the need for costly enzymes and bulky equipment, and thus demonstrates promise as a rapid point-of-care diagnostic tool for detection of early onset preeclampsia in developing nation settings. PMID:23187309

  19. Detection of nucleic acid sequences by invader-directed cleavage

    DOEpatents

    Brow, Mary Ann D.; Hall, Jeff Steven Grotelueschen; Lyamichev, Victor; Olive, David Michael; Prudent, James Robert

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The 5' nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based by charge.

  20. Detection of Acid Fast Bacilli in Saliva using Papanicolaou Stain Induced Fluorescence Method Versus Fluorochrome Staining: An Evaluative Study

    PubMed Central

    (Munot), Priya P Lunawat; Mhapuskar, Amit A; Ganvir, S M; Hazarey, Vinay K; Mhapuskar, Madhavi A; Kulkarni, Dinraj

    2015-01-01

    Background: Fifty years after effective chemotherapy, tuberculosis (TB) still remains leading infectious cause of adult mortality. The aim of present study was to evaluate diagnostic utility of papanicolaou (Pap) stain induced fluorescence microscopic examination of salivary smears in the diagnosis of pulmonary TB. Materials and Methods: Cross-sectional study of 100 individuals clinically suspected of suffering from active pulmonary TB. Control group – 50 individuals are suffering from any pulmonary disease other than TB such as pneumonia or bronchiogenic carcinoma. Fluorescence microscopic examination of two salivary smears stained by Pap stain and auramine-rhodamine (A-R) stain respectively for each patient. Ziehl–Neelsen stained sputum smear examined under the light microscope for each patient. Culture was done in all the patients for microbiological confirmation. McNemar's Chi-square analysis, Kappa test, and Z-test. Results: The sensitivities of the three staining methods using culture as a reference method were 93.02%, 88.37% and 87.20% for Pap, A-R and Ziehl–Neelson respectively. Conclusion: Pap-induced fluorescence of salivary smears is a safe, reliable and rapid method, which can prove as a valuable diagnostic tool for diagnosis of TB. PMID:26229384

  1. Be an acid rain detective

    SciTech Connect

    Atwill, L.

    1982-07-01

    Acid rain is discussed in a question and answer format. The article is aimed at educating sport fishermen on the subject, and also to encourage them to write their congressmen, senators, and the President about the acid rain problem. The article also announces the availability of an acid rain test kit available through the magazine, ''Sports Afield.'' The kit consists of pH-test paper that turns different shades of pink and blue according to the pH of the water tested. The color of the test paper is then compared to a color chart furnished in the kit and an approximate pH can be determined.

  2. Solvent accessible surface area-based hot-spot detection methods for protein-protein and protein-nucleic acid interfaces.

    PubMed

    Munteanu, Cristian R; Pimenta, António C; Fernandez-Lozano, Carlos; Melo, André; Cordeiro, Maria N D S; Moreira, Irina S

    2015-05-26

    Due to the importance of hot-spots (HS) detection and the efficiency of computational methodologies, several HS detecting approaches have been developed. The current paper presents new models to predict HS for protein-protein and protein-nucleic acid interactions with better statistics compared with the ones currently reported in literature. These models are based on solvent accessible surface area (SASA) and genetic conservation features subjected to simple Bayes networks (protein-protein systems) and a more complex multi-objective genetic algorithm-support vector machine algorithms (protein-nucleic acid systems). The best models for these interactions have been implemented in two free Web tools. PMID:25845030

  3. Method for nucleic acid isolation using supercritical fluids

    DOEpatents

    Nivens, D.E.; Applegate, B.M.

    1999-07-13

    A method is disclosed for detecting the presence of a microorganism in an environmental sample involves contacting the sample with a supercritical fluid to isolate nucleic acid from the microorganism, then detecting the presence of a particular sequence within the isolated nucleic acid. The nucleic acid may optionally be subjected to further purification. 4 figs.

  4. Method for nucleic acid isolation using supercritical fluids

    DOEpatents

    Nivens, David E.; Applegate, Bruce M.

    1999-01-01

    A method for detecting the presence of a microorganism in an environmental sample involves contacting the sample with a supercritical fluid to isolate nucleic acid from the microorganism, then detecting the presence of a particular sequence within the isolated nucleic acid. The nucleic acid may optionally be subjected to further purification.

  5. Method for identifying and quantifying nucleic acid sequence aberrations

    DOEpatents

    Lucas, Joe N.; Straume, Tore; Bogen, Kenneth T.

    1998-01-01

    A method for detecting nucleic acid sequence aberrations by detecting nucleic acid sequences having both a first and a second nucleic acid sequence type, the presence of the first and second sequence type on the same nucleic acid sequence indicating the presence of a nucleic acid sequence aberration. The method uses a first hybridization probe which includes a nucleic acid sequence that is complementary to a first sequence type and a first complexing agent capable of attaching to a second complexing agent and a second hybridization probe which includes a nucleic acid sequence that selectively hybridizes to the second nucleic acid sequence type over the first sequence type and includes a detectable marker for detecting the second hybridization probe.

  6. Method for identifying and quantifying nucleic acid sequence aberrations

    DOEpatents

    Lucas, J.N.; Straume, T.; Bogen, K.T.

    1998-07-21

    A method is disclosed for detecting nucleic acid sequence aberrations by detecting nucleic acid sequences having both a first and a second nucleic acid sequence type, the presence of the first and second sequence type on the same nucleic acid sequence indicating the presence of a nucleic acid sequence aberration. The method uses a first hybridization probe which includes a nucleic acid sequence that is complementary to a first sequence type and a first complexing agent capable of attaching to a second complexing agent and a second hybridization probe which includes a nucleic acid sequence that selectively hybridizes to the second nucleic acid sequence type over the first sequence type and includes a detectable marker for detecting the second hybridization probe. 11 figs.

  7. 4-mercaptophenylboronic acid functionalized gold nanoparticles for colorimetric sialic acid detection.

    PubMed

    Sankoh, Supannee; Thammakhet, Chongdee; Numnuam, Apon; Limbut, Warakorn; Kanatharana, Proespichaya; Thavarungkul, Panote

    2016-11-15

    A simple and selective colorimetric sensor for sialic acid detection, based on the aggregation of 4-mercaptophenylboronic acid functionalized gold nanoparticles (4-MPBA-AuNPs) was developed. The color of the solution changed from wine-red to blue after binding with sialic acid. The colorimetric sensor provided good analytical performances with a linear dynamic range of 80µM to 2.00mM and a 68±2µM limit of detection without any effect from possible interferences and sample matrix. In addition, the quantitative results were obtained within only 10min. This developed sensor was used to detect sialic acid in blood serum samples and the results were in good agreement with those from the current periodate-resorcinol method (P>0.05) thus indicating that this developed colorimetric sensor can be used as an alternative method for sialic acid detection with a shorter analysis time and a high accuracy. PMID:27266659

  8. Methods of DNA methylation detection

    NASA Technical Reports Server (NTRS)

    Maki, Wusi Chen (Inventor); Filanoski, Brian John (Inventor); Mishra, Nirankar (Inventor); Rastogi, Shiva (Inventor)

    2010-01-01

    The present invention provides for methods of DNA methylation detection. The present invention provides for methods of generating and detecting specific electronic signals that report the methylation status of targeted DNA molecules in biological samples.Two methods are described, direct and indirect detection of methylated DNA molecules in a nano transistor based device. In the direct detection, methylated target DNA molecules are captured on the sensing surface resulting in changes in the electrical properties of a nano transistor. These changes generate detectable electronic signals. In the indirect detection, antibody-DNA conjugates are used to identify methylated DNA molecules. RNA signal molecules are generated through an in vitro transcription process. These RNA molecules are captured on the sensing surface change the electrical properties of nano transistor thereby generating detectable electronic signals.

  9. GMDD: a database of GMO detection methods

    PubMed Central

    Dong, Wei; Yang, Litao; Shen, Kailin; Kim, Banghyun; Kleter, Gijs A; Marvin, Hans JP; Guo, Rong; Liang, Wanqi; Zhang, Dabing

    2008-01-01

    Background Since more than one hundred events of genetically modified organisms (GMOs) have been developed and approved for commercialization in global area, the GMO analysis methods are essential for the enforcement of GMO labelling regulations. Protein and nucleic acid-based detection techniques have been developed and utilized for GMOs identification and quantification. However, the information for harmonization and standardization of GMO analysis methods at global level is needed. Results GMO Detection method Database (GMDD) has collected almost all the previous developed and reported GMOs detection methods, which have been grouped by different strategies (screen-, gene-, construct-, and event-specific), and also provide a user-friendly search service of the detection methods by GMO event name, exogenous gene, or protein information, etc. In this database, users can obtain the sequences of exogenous integration, which will facilitate PCR primers and probes design. Also the information on endogenous genes, certified reference materials, reference molecules, and the validation status of developed methods is included in this database. Furthermore, registered users can also submit new detection methods and sequences to this database, and the newly submitted information will be released soon after being checked. Conclusion GMDD contains comprehensive information of GMO detection methods. The database will make the GMOs analysis much easier. PMID:18522755

  10. Method for detecting an element

    DOEpatents

    Blackwood, Larry G.; Reber, Edward L.; Rohde, Kenneth W.

    2007-02-06

    A method for detecting an element is disclosed and which includes the steps of providing a gamma-ray spectrum which depicts, at least in part, a test region having boundaries, and which has a small amount of the element to be detected; providing a calculation which detects the small amount of the element to be detected; and providing a moving window and performing the calculation within the moving window, and over a range of possible window boundaries within the test region to determine the location of the optimal test region within the gamma-ray spectrum.

  11. Nucleic acid in-situ hybridization detection of infectious agents

    NASA Astrophysics Data System (ADS)

    Thompson, Curtis T.

    2000-04-01

    Limitations of traditional culture methods and newer polymerase chain reaction (PCR)-based methods for detection and speciation of infectious agents demonstrate the need for more rapid and better diagnostics. Nucleic acid hybridization is a detection technology that has gained wide acceptance in cancer and prenatal cytogenetics. Using a modification of the nucleic acid hybridization technique known as fluorescence in-situ hybridization, infectious agents can be detected in a variety of specimens with high sensitivity and specificity. The specimens derive from all types of human and animal sources including body fluids, tissue aspirates and biopsy material. Nucleic acid hybridization can be performed in less than one hour. The result can be interpreted either using traditional fluorescence microscopy or automated platforms such as micro arrays. This paper demonstrates proof of concept for nucleic acid hybridization detection of different infectious agents. Interpretation within a cytologic and histologic context is possible with fluorescence microscopic analysis, thereby providing confirmatory evidence of hybridization. With careful probe selection, nucleic acid hybridization promises to be a highly sensitive and specific practical diagnostic alternative to culture, traditional staining methods, immunohistochemistry and complicated nucleic acid amplification tests.

  12. A Rapid Method for Determination of the Main Conjugated Linoleic Acid Precursors (C18:2 n-6 and C18:3 n-3) in Forage by Capillary Zone Electrophoresis with Ultraviolet Detection Using Gas Chromatography with Flame Ionization Detection as a Comparative Method.

    PubMed

    de Jesus Coelho Castro, Renata; Sobrinho, Fausto Souza; Sundfeld da Gama, Marco Antônio; Takabayashi Sato, Renata; Lavorato Lima, Larissa; Leal de Oliveira, Marcone Augusto

    2015-01-01

    A rapid method has been proposed for determination of the main conjugated linoleic acid precursors such as linoleic (C18:2 n-6) and linolenic (C18:3 n-3) acids in forages by capillary zone electrophoresis (CZE) with direct UV detection at 200 nm. Among the fatty acids found in forages, C18:2 n-6 and C18:3 n-3 have received particular attention due to their roles as precursors for the synthesis of conjugated linoleic acid, a class of health-enhancing compounds that is predominantly found in dairy products. The electrolyte background consisted of 12.0 mmol/L tetraborate buffer (pH 9.2) added to 12.0 mmol/L Brij 35®, 17% acetonitrile, and 33% methanol. Under the optimized conditions, the baseline separation of C18:2 n-6 and C18:3 n-3 was achieved within 4 min. The CZE-UV method was compared to GC with a flame ionization detector, which is the American Oil Chemists' Society (AOCS 996.06) official method for fatty acid analysis. The methods did not show any evidence of significant differences within 95% confidence interval (P>0.05). The CZE-UV method was successfully applied to the analysis of 80 genotypes of Brachiaria ruzizienses clones submitted to a genetic improvement program in agricultural research. PMID:26651572

  13. Automated Methods for Multiplexed Pathogen Detection

    SciTech Connect

    Straub, Tim M.; Dockendorff, Brian P.; Quinonez-Diaz, Maria D.; Valdez, Catherine O.; Shutthanandan, Janani I.; Tarasevich, Barbara J.; Grate, Jay W.; Bruckner-Lea, Cindy J.

    2005-09-01

    Detection of pathogenic microorganisms in environmental samples is a difficult process. Concentration of the organisms of interest also co-concentrates inhibitors of many end-point detection methods, notably, nucleic acid methods. In addition, sensitive, highly multiplexed pathogen detection continues to be problematic. The primary function of the BEADS (Biodetection Enabling Analyte Delivery System) platform is the automated concentration and purification of target analytes from interfering substances, often present in these samples, via a renewable surface column. In one version of BEADS, automated immunomagnetic separation (IMS) is used to separate cells from their samples. Captured cells are transferred to a flow-through thermal cycler where PCR, using labeled primers, is performed. PCR products are then detected by hybridization to a DNA suspension array. In another version of BEADS, cell lysis is performed, and community RNA is purified and directly labeled. Multiplexed detection is accomplished by direct hybridization of the RNA to a planar microarray. The integrated IMS/PCR version of BEADS can successfully purify and amplify 10 E. coli O157:H7 cells from river water samples. Multiplexed PCR assays for the simultaneous detection of E. coli O157:H7, Salmonella, and Shigella on bead suspension arrays was demonstrated for the detection of as few as 100 cells for each organism. Results for the RNA version of BEADS are also showing promising results. Automation yields highly purified RNA, suitable for multiplexed detection on microarrays, with microarray detection specificity equivalent to PCR. Both versions of the BEADS platform show great promise for automated pathogen detection from environmental samples. Highly multiplexed pathogen detection using PCR continues to be problematic, but may be required for trace detection in large volume samples. The RNA approach solves the issues of highly multiplexed PCR and provides ''live vs. dead'' capabilities. However

  14. On the detectability of acid formation in clouds

    SciTech Connect

    Kelly, T.J.; Schwartz, S.E.; Daum, P.H.

    1987-03-01

    This paper evaluates the feasibility of detecting by means of field measurements the occurrence of acid forming reactions in natural clouds. This evaluation is performed by calculating the changes in reagent and product concentrations expected from four potentially important in-cloud acid production mechanisms, in representative cloud types, and comparing those changes with concentration differences detectable by available analytical methods. The four acid production mechanisms considered are: aqueous-phase reactions of SO/sub 2/ with O/sub 3/ and with H/sub 2/O/sub 2/, and gas-phase reactions of NO/sub 2/ with OH radical and with O/sub 3/, the latter leading to acid formation by reaction of N/sub 2/O/sub 5/ with cloud liquid water. The cloud types considered are fog, stratus, cumulus, and mountain lee wave. This evaluation indicates that oxidation of SO/sub 2/ by H/sub 2/O/sub 2/ should be detectable in a wide variety of cloud conditions, but that oxidation of SO/sub 2/ by O/sub 3/ is unlikely to be detected by field measurements. The reactions oxidizing NO/sub 2/ may be detectable in fog and stratus clouds, which provide long in-cloud residence times. The paper includes discussion of factors which favor or hinder detection of acid production in clouds, and reviews evidence from published field studies on the occurrence of such production.

  15. Indirect electrochemical detection for total bile acids in human serum.

    PubMed

    Zhang, Xiaoqing; Zhu, Mingsong; Xu, Biao; Cui, Yue; Tian, Gang; Shi, Zhenghu; Ding, Min

    2016-11-15

    Bile acids level in serum is a useful index for screening and diagnosis of hepatobiliary diseases. As bile acids concentration is closely related to the degree of hepatobiliary diseases, detecting it is a vital factor to understand the stage of the diseases. The prevalent determination for bile acids is the enzymatic cycling method which has low sensitivity while reagent-consuming. It is desirable to develop a new method with lower cost and higher sensitivity. An indirect electrochemical detection (IED) for bile acids in human serum was established using the screen printed carbon electrode (SPCE). Since bile acids do not show electrochemical signals, they were converted to 3-ketosteroids by 3-α-hydroxysteroid dehydrogenase (3α-HSD) in the presence of nicotinamide adenine dinucleotide (NAD(+)), which was reduced to NADH. NADH could then be oxidized on the surface of SPCE, generating a signal that was used to calculate the total bile acids (TBA) concentration. A good linear calibration for TBA was obtained at the concentration range from 5.00μM to 400μM in human serum. Both the precisions and recoveries were sufficient to be used in a clinical setting. The TBA concentrations in 35 human serum samples by our IED method didn't show significant difference with the result by enzymatic cycling method, using the paired t-test. Moreover, our IED method is reagent-saving, sensitive and cost-effective. PMID:27236139

  16. Nucleic acid detection in the diagnosis and prevention of schistosomiasis.

    PubMed

    He, Ping; Song, Lan-Gui; Xie, Hui; Liang, Jin-Yi; Yuan, Dong-Ya; Wu, Zhong-Dao; Lv, Zhi-Yue

    2016-01-01

    Schistosomiasis is an important zoonotic parasitic disease that causes serious harms to humans and animals. Surveillance and diagnosis play key roles in schistosomiasis control, however, current techniques for surveillance and diagnosis of the disease have limitations. As genome data for parasites are increasing, novel techniques for detection incorporating nucleotide sequences are receiving widespread attention. These sensitive, specific, and rapid detection methods are particularly important in the diagnosis of low-grade and early infections, and may prove to have clinical significance. This paper reviews the progress of nucleic acid detection in the diagnosis and prevention of schistosomiasis, including such aspects as the selection of target genes, and development and application of nucleic acid detection methods. PMID:27025210

  17. A novel method for detection of apoptosis

    SciTech Connect

    Zagariya, Alexander M.

    2012-04-15

    There are two different Angiotensin II (ANG II) peptides in nature: Human type (ANG II) and Bovine type (ANG II*). These eight amino acid peptides differ only at position 5 where Valine is replaced by Isoleucine in the Bovine type. They are present in all species studied so far. These amino acids are different by only one atom of carbon. This difference is so small, that it will allow any of ANG II, Bovine or Human antibodies to interact with all species and create a universal method for apoptosis detection. ANG II concentrations are found at substantially higher levels in apoptotic, compared to non-apoptotic, tissues. ANG II accumulation can lead to DNA damage, mutations, carcinogenesis and cell death. We demonstrate that Bovine antiserum can be used for universal detection of apoptosis. In 2010, the worldwide market for apoptosis detection reached the $20 billion mark and significantly increases each year. Most commercially available methods are related to Annexin V and TUNNEL. Our new method based on ANG II is more widely known to physicians and scientists compared to previously used methods. Our approach offers a novel alternative for assessing apoptosis activity with enhanced sensitivity, at a lower cost and ease of use.

  18. Nucleic acid arrays and methods of synthesis

    DOEpatents

    Sabanayagam, Chandran R.; Sano, Takeshi; Misasi, John; Hatch, Anson; Cantor, Charles

    2001-01-01

    The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

  19. A rapid and simple method for the determination of 3,4-dihydroxyphenylacetic acid, norepinephrine, dopamine, and serotonin in mouse brain homogenate by HPLC with fluorimetric detection.

    PubMed

    De Benedetto, Giuseppe Egidio; Fico, Daniela; Pennetta, Antonio; Malitesta, Cosimino; Nicolardi, Giuseppe; Lofrumento, Dario Domenico; De Nuccio, Francesco; La Pesa, Velia

    2014-09-01

    A fast and simple isocratic high-performance liquid chromatography method for the determination of 3,4-dihydroxyphenylacetic acid (DOPAC), norepinephrine (NE), dopamine (DA), and serotonin (5-HT) in homogenate samples of mouse striatum employing the direct fluorescence of the neurotransmitters is described. The method has been optimized and validated. The analytes were separated in 15min on a reversed-phase column (C18) with acetate buffer (pH 4.0, 12mM)-methanol (86:14, v/v) as mobile phase; the flow rate was 1ml/min. The fluorescence measurements were carried out at 320nm with excitation at 279nm. The calibration curve for DA was linear up to about 2.5μg/ml, with a coefficient of determination (r(2)) of 0.9995 with a lower limit of quantification of 0.031μg/ml. Since the procedure does not involve sample pre-purification or derivatisation, the recovery ranged from 97% to 102% and relative standard deviation (RSD) was better than 2.9%, the use of the internal standard is not mandatory, further simplifying the method. Similar performance was obtained for the other analytes. As a result, thanks to its simplicity, rapidity and adequate working range, the method can be used for the determination of 3,4-dihydroxyphenylacetic acid, dopamine, norepinephrine and serotonin in animal tissues. An experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson-like disease has been used to demonstrate the method is fit-for-purpose. PMID:24971521

  20. Leak detection method and apparatus

    SciTech Connect

    Fries, B.A.

    1982-05-11

    A method and apparatus are described for using sulfur hexafluoride to detect leaks in fluid processing systems. Leak detection can be performed with the processing system continuing in operation. This apparatus detects leakage through a partition separating a portion of a first path from portion of a second path in a fluid processing system, while operation of the system is continued. The apparatus comprises a combination of 1) means for introducing a known quantity of sulfur hexafluoride into fluid flowing in the first path upstream of a partition; 2) means for continuously removing a sample of fluid flowing in the second path at a locus downstream of the partition; 3) means for removing normally liquid components from the sample; 4) means for testing the sample to determine the presence of sulfur hexafluoride; and 5) means for indicating the amount of sulfur hexafluoride in the sample. 2 claims.

  1. Survey of Anomaly Detection Methods

    SciTech Connect

    Ng, B

    2006-10-12

    This survey defines the problem of anomaly detection and provides an overview of existing methods. The methods are categorized into two general classes: generative and discriminative. A generative approach involves building a model that represents the joint distribution of the input features and the output labels of system behavior (e.g., normal or anomalous) then applies the model to formulate a decision rule for detecting anomalies. On the other hand, a discriminative approach aims directly to find the decision rule, with the smallest error rate, that distinguishes between normal and anomalous behavior. For each approach, we will give an overview of popular techniques and provide references to state-of-the-art applications.

  2. Method for detecting toxic gases

    DOEpatents

    Stetter, J.R.; Zaromb, S.; Findlay, M.W. Jr.

    1991-10-08

    A method is disclosed which is capable of detecting low concentrations of a pollutant or other component in air or other gas. This method utilizes a combination of a heating filament having a catalytic surface of a noble metal for exposure to the gas and producing a derivative chemical product from the component. An electrochemical sensor responds to the derivative chemical product for providing a signal indicative of the product. At concentrations in the order of about 1-100 ppm of tetrachloroethylene, neither the heating filament nor the electrochemical sensor is individually capable of sensing the pollutant. In the combination, the heating filament converts the benzyl chloride to one or more derivative chemical products which may be detected by the electrochemical sensor. 6 figures.

  3. Phenol-Sulfuric Acid Method for Total Carbohydrates

    NASA Astrophysics Data System (ADS)

    Nielsen, S. Suzanne

    The phenol-sulfuric acid method is a simple and rapid colorimetric method to determine total carbohydrates in a sample. The method detects virtually all classes of carbohydrates, including mono-, di-, oligo-, and polysaccharides. Although the method detects almost all carbohydrates, the absorptivity of the different carbohydrates varies. Thus, unless a sample is known to contain only one carbohydrate, the results must be expressed arbitrarily in terms of one carbohydrate.

  4. Efficient, validated method for detection of mycobacterial growth in liquid culture media by use of bead beating, magnetic-particle-based nucleic acid isolation, and quantitative PCR.

    PubMed

    Plain, Karren M; Waldron, Anna M; Begg, Douglas J; de Silva, Kumudika; Purdie, Auriol C; Whittington, Richard J

    2015-04-01

    Pathogenic mycobacteria are difficult to culture, requiring specialized media and a long incubation time, and have complex and exceedingly robust cell walls. Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease, a chronic wasting disease of ruminants, is a typical example. Culture of MAP from the feces and intestinal tissues is a commonly used test for confirmation of infection. Liquid medium offers greater sensitivity than solid medium for detection of MAP; however, support for the BD Bactec 460 system commonly used for this purpose has been discontinued. We previously developed a new liquid culture medium, M7H9C, to replace it, with confirmation of growth reliant on PCR. Here, we report an efficient DNA isolation and quantitative PCR methodology for the specific detection and confirmation of MAP growth in liquid culture media containing egg yolk. The analytical sensitivity was at least 10(4)-fold higher than a commonly used method involving ethanol precipitation of DNA and conventional PCR; this may be partly due to the addition of a bead-beating step to manually disrupt the cell wall of the mycobacteria. The limit of detection, determined using pure cultures of two different MAP strains, was 100 to 1,000 MAP organisms/ml. The diagnostic accuracy was confirmed using a panel of cattle fecal (n=54) and sheep fecal and tissue (n=90) culture samples. This technique is directly relevant for diagnostic laboratories that perform MAP cultures but may also be applicable to the detection of other species, including M. avium and M. tuberculosis. PMID:25609725

  5. Nucleic acid detection systems for enteroviruses.

    PubMed Central

    Rotbart, H A

    1991-01-01

    The enteroviruses comprise nearly 70 human pathogens responsible for a wide array of diseases including poliomyelitis, meningitis, myocarditis, and neonatal sepsis. Current diagnostic tests for the enteroviruses are limited in their use by the slow growth, or failure to grow, of certain serotypes in culture, the antigenic diversity among the serotypes, and the low titer of virus in certain clinical specimens. Within the past 6 years, applications of molecular cloning techniques, in vitro transcription vectors, automated nucleic acid synthesis, and the polymerase chain reaction have resulted in significant progress toward nucleic acid-based detection systems for the enteroviruses that take advantage of conserved genomic sequences across many, if not all, serotypes. Similar approaches to the study of enteroviral pathogenesis have already produced dramatic advances in our understanding of how these important viruses cause their diverse clinical spectra. PMID:1649002

  6. Reliability of pyuria detection method.

    PubMed

    Saito, A; Kawada, Y

    1994-01-01

    The reliability of two methods for the detection of pyuria was studied in a total of 106 urine samples obtained from patients with identifiable underlying urinary tract disease. The coefficient of variation (CV) was significantly higher in the microscopic than in the counting chamber method. The CV obtained with the use of the KOVA slide 10 grid, a disposable and less expensive counting chamber, was identical to that obtained with the Bürker-Türk counting chamber. Only 50% of the patients who were proven to have pyuria of > or = 5 WBCs/HPF by the microscopic method had significant bacteriuria of > or = 10(4) bacteria per ml of urine. On the other hand, 95% and 90% of the patients who were proven to have pyuria of > or = 10 WBCs/mm3 with the Bürker-Türk and Fuchs-Rosenthal counting chambers had significant bacteriuria. It was concluded that the counting chamber provides a reliable method for the detection of pyuria and is highly predictive for the presence of significant bacteriuria. The KOVA slide 10 grid is an acceptable alternative to the regular counting chamber. PMID:7519582

  7. Method for detecting toxic gases

    DOEpatents

    Stetter, Joseph R.; Zaromb, Solomon; Findlay, Jr., Melvin W.

    1991-01-01

    A method capable of detecting low concentrations of a pollutant or other component in air or other gas, utilizing a combination of a heating filament having a catalytic surface of a noble metal for exposure to the gas and producing a derivative chemical product from the component, and an electrochemical sensor responsive to the derivative chemical product for providing a signal indicative of the product. At concentrations in the order of about 1-100 ppm of tetrachloroethylene, neither the heating filament nor the electrochemical sensor is individually capable of sensing the pollutant. In the combination, the heating filament converts the benzyl chloride to one or more derivative chemical products which may be detected by the electrochemical sensor.

  8. Acid Cleavable Surface enhanced Raman Tagging for Protein Detection

    PubMed Central

    Zhang, Dongmao; Vangala, Karthikeshwar; Li, Shaoyong; Yanney, Michael; Xia, Hao; Zou, Sige; Sygula, Andrzej

    2010-01-01

    Dye conjugation is a common strategy improving the surface enhanced Raman detection sensitivity of biomolecules. Reported is a proof-of-concept study of a novel surface enhanced Raman spectroscopic tagging strategy termed as acid-cleavable SERS tag (ACST) method. Using Rhodamine B as the starting material, we prepared the first ACST prototype that consisted of, from the distal end, a SERS tag moiety (STM), an acid-cleavable linker, and a protein reactive moiety. Complete acid cleavage of the ACST tags was achieved at a very mild condition that is 1.5% trifluoroacetic acid (TFA) aqueous solution at room temperature. SERS detection of this ACST tagged protein was demonstrated using bovine serum albumin (BSA) as the model protein. While the SERS spectrum of intact ACST-BSA was entirely dominated by the fluorescent signal of STM, quality SERS spectra can be readily obtained with the acid cleaved ACST-BSA conjugates. Separation of the acid cleaved STM from protein further enhances the SERS sensitivity. Current SERS detection sensitivity, achieved with the acid cleaved ACST-BSA conjugate is ~5 nM in terms of the BSA concentration and ~1.5 nM in ACST content. The linear dynamic range of the cleaved ACST-BSA conjugate spans four orders of magnitudes from ~10 nM to ~100 μM in protein concentrations. Further improvement in the SERS sensitivity can be achieved with resonance Raman acquisition. This cleavable tagging strategy may also be used for elimination of protein interference in fluorescence based biomolecule detection. PMID:21109888

  9. Structure-property study of the Raman spectroscopy detection of fusaric acid and analogs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food security can benefit from the development of selective methods to detect toxins. Fusaric acid is a mycotoxin produced by certain fungi occasionally found in agricultural commodities. Raman spectroscopy allows selective detection of analytes associated with certain spectral characteristics relat...

  10. Bacteria detection instrument and method

    NASA Technical Reports Server (NTRS)

    Renner, W.; Fealey, R. D. (Inventor)

    1972-01-01

    A method and apparatus for screening a sample fluid for bacterial presence are disclosed wherein the fluid sample is mixed with culture media of sufficient quantity to permit bacterial growth in order to obtain a test solution. The concentration of oxygen dissolved in the test solution is then monitored using the potential difference between a reference electrode and a noble metal electrode which are in contact with the test solution. The change in oxygen concentration which occurs during a period of time as indicated by the electrode potential difference is compared with a detection criterion which exceeds the change which would occur absent bacteria.

  11. LABORATORY DETECTION OF THIOCYANIC ACID HSCN

    SciTech Connect

    Bruenken, S.; Yu, Z.; Gottlieb, C. A.; McCarthy, M. C.; Thaddeus, P. E-mail: cgottlieb@cfa.harvard.ed E-mail: pthaddeus@cfa.harvard.ed

    2009-12-01

    The rotational spectrum of thiocyanic acid HSCN, a highly polar isomer of the well-known astronomical molecule isothiocyanic acid HNCS, has been measured in two radio bands: in the centimeter-wave band by Fourier transform microwave spectroscopy in a molecular beam, and in the millimeter-wave band by long-path absorption spectroscopy in a low-pressure glow discharge. Twelve spectroscopic constants were derived from more than 60 a-type rotational transitions between 11 and 346 GHz with J up to 30 and K{sub a} <= 6, including seven centimeter-wave transitions with resolved hyperfine structure. With these constants the rotational spectrum in the K{sub a} = 0 and K{sub a} = 1 ladders-those most likely to be observed in space-can now be calculated up to 400 GHz with formal uncertainties of less than 0.2 km s{sup -1} in equivalent radial velocity. Thiocyanic acid was recently identified in Sgr B2 by Halfen et al. following the laboratory measurements, and there is possible evidence for it in cold dark clouds, with the implication that HSCN may be detectable in many galactic sources.

  12. Explosives detection system and method

    DOEpatents

    Reber, Edward L.; Jewell, James K.; Rohde, Kenneth W.; Seabury, Edward H.; Blackwood, Larry G.; Edwards, Andrew J.; Derr, Kurt W.

    2007-12-11

    A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

  13. Affinity sensor using 3-aminophenylboronic acid for bacteria detection.

    PubMed

    Wannapob, Rodtichoti; Kanatharana, Proespichaya; Limbut, Warakorn; Numnuam, Apon; Asawatreratanakul, Punnee; Thammakhet, Chongdee; Thavarungkul, Panote

    2010-10-15

    Boronic acid that can reversibly bind to diols was used to detect bacteria through its affinity binding reaction with diol-groups on bacterial cell walls. 3-aminophenylboronic acid (3-APBA) was immobilized on a gold electrode via a self-assembled monolayer. The change in capacitance of the sensing surface caused by the binding between 3-APBA and bacteria in a flow system was detected by a potentiostatic step method. Under optimal conditions the linear range of 1.5×10(2)-1.5×10(6) CFU ml(-1) and the detection limit of 1.0×10(2) CFU ml(-1) was obtained. The sensing surface can be regenerated and reused up to 58 times. The method was used for the analysis of bacteria in several types of water, i.e., bottled, well, tap, reservoir and wastewater. Compared with the standard plate count method, the results were within one standard deviation of each other. The proposed method can save both time and cost of analysis. The electrode modified with 3-APBA would also be applicable to the detection of other cis-diol-containing analytes. The concept could be extended to other chemoselective ligands, offering less expensive and more robust affinity sensors for a wide range of compounds. PMID:20801635

  14. Optimized Dispersive Liquid-Liquid Microextraction Method and High Performance Liquid Chromatography with Ultraviolet Detection for Simultaneous Determination of Sorbic and Benzoic Acids and Evaluation of Contamination of These Preservatives in Iranian Foods.

    PubMed

    Javanmardi, Fardin; Arefhosseini, Seyyed Rafie; Ansarin, Masood; Nemati, Mahboob

    2015-01-01

    A rapid, simple, and sensitive dispersive liquid-liquid microextraction procedure followed by HPLC-UV was applied to determine the benzoate and sorbate in foods. The method was optimized for some variables including extraction solvent type and volume, dispersing solvent type and volume, and the effects of salt and pH. Optimum conditions were determined as follows: sample volume, 5 mL; extraction solvent (chloroform) volume, 250 μL; disperser solvent (acetone) volume, 1.2 mL; NaCl amount, 0.75 g/5 mL at pH 4. Sixty samples were analyzed, including 15 doogh, 15 fruit juice, 15 cookie, and 15 tomato paste; benzoic acid was detected in 57 samples (95%) at levels up to 448.1 μg/mL and sorbic acid in 31 samples (51.6%) at levels up to 1369 μg/mL. Under the optimum experimental conditions, the LOD and LOQ were determined as 0.1 and 0.5 μg/mL for benzoate and 0.08 and 0.3 μg/mL for sorbate, respectively. The results showed that these preservatives are commonly used at high levels in yogurt drinks (dooghs) and cookies. Also, the concentration of benzoic acid that was detected in the tomato paste and fruit juice samples was low but may affect children and sensitive persons. PMID:26268979

  15. Wire detecting apparatus and method

    SciTech Connect

    Kronberg, J.W.

    1991-12-31

    This invention is comprised of an apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receiver`s position with respect to the wiring. The receiver`s audible signal is strongest when the receiver is directly above the wiring and the long axis of the receiver`s coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring`s concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest.

  16. Immunofluorescence detection methods using microspheres

    NASA Astrophysics Data System (ADS)

    Szurdoki, Ferenc; Michael, Karri L.; Agrawal, Divya; Taylor, Laura C.; Schultz, Sandra L.; Walt, David R.

    1999-01-01

    Microsphere-based immunoassays were devised for compounds of agricultural and biomedical interest (e.g., digoxin, theophylline, and zearalenone). Commercially available microspheres with surface functional groups for chemical derivatization were used as solid carriers. After immobilizing the target substances, the surface of the haptenized microspheres was blocked by a protein to reduce aspecific binding. Competitive immunoassays were performed using the functionalized microspheres and antibodies labeled with horseradish peroxidase. Immunofluorescence signal amplification was achieved by enzyme-catalyzed reporter deposition (CARD). An epifluorescence microscope, a CCD camera interfaced with a computer, and microscopy image analysis software were employed for quantitative detection of fluorescent light emitted from individual microspheres. Integration of several such immunoassays and application of an optical encoding method enabled multianalyte determination. These immunoassays can also be utilized in an immunosensor array format. This immunoarray format could facilitate miniaturization and automation of multianalyte immunoassays.

  17. Liquid crystal based biosensors for bile acid detection

    NASA Astrophysics Data System (ADS)

    He, Sihui; Liang, Wenlang; Tanner, Colleen; Fang, Jiyu; Wu, Shin-Tson

    2013-03-01

    The concentration level of bile acids is a useful indicator for early diagnosis of liver diseases. The prevalent measurement method in detecting bile acids is the chromatography coupled with mass spectrometry, which is precise yet expensive. Here we present a biosensor platform based on liquid crystal (LC) films for the detection of cholic acid (CA). This platform has the advantage of low cost, label-free, solution phase detection and simple analysis. In this platform, LC film of 4-Cyano-4'-pentylbiphenyl (5CB) was hosted by a copper grid supported with a polyimide-coated glass substrate. By immersing into sodium dodecyl sulfate (SDS) solution, the LC film was coated with SDS which induced a homeotropic anchoring of 5CB. Addition of CA introduced competitive adsorption between CA and SDS at the interface, triggering a transition from homeotropic to homogeneous anchoring. The detection limit can be tuned by changing the pH value of the solution from 12uM to 170uM.

  18. Well acidizing compositions and method

    SciTech Connect

    Gardener, T.R.; Dill, W.R.; Ford, W.G.F.; King, K.L.

    1991-07-23

    This patent describes a concentrate which forms an acid internal microemulsion well treatment composition when added to an acid treatment fluid. It comprises in the range of from about 20% to about 98% by weight of a hydrocarbon carrier fluid; in the range of from about 1% to about 50% by weight of an alkyl alcohol having in the range of from about 4 to 18 carbon atoms; and in the range of from about 1% to about 50% by weight of an emulsifying agent comprising at least one compound selected from the group consisting of amine salts having ester or amide linkages and propoxylated alcohols, each of the components being different compounds or different mixtures of compounds.

  19. Chromatographic analysis of amino and organic acids in physiological fluids to detect inborn errors of metabolism.

    PubMed

    Woontner, Michael; Goodman, Stephen I

    2006-11-01

    This unit describes methods for the preparation of samples for analysis of physiological amino acids and organic acids. Amino acids are analyzed by ion-exchange chromatography using an automated system. Organic acids are analyzed by gas-chromatography/mass spectrometry (GC-MS). Analysis of amino and organic acids is necessary to detect and monitor the treatment of many inborn errors of metabolism. PMID:18428392

  20. A sensitive and efficient method for determination of N-acetylhexosamines and N-acetylneuraminic acid in breast milk and milk-based products by high-performance liquid chromatography via UV detection and mass spectrometry identification.

    PubMed

    Chuanxiang, Wu; Lian, Xia; Lijie, Liu; Fengli, Qu; Zhiwei, Sun; Xianen, Zhao; Jinmao, You

    2016-02-01

    A sensitive and efficient method of high performance liquid chromatography using 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP) as pre-column derivatization reagent coupled with UV detection (HPLC-UV) and online mass spectrometry identification was established for determination of the most common N-Acetylhexosamines (N-acetyl-d-glucosamine (GlcNAc) and N-acetyl-d-galactosamine (GalNAc)) and N-acetylneuraminic acid (Neu5Ac). In order to obtain the highest liberation level of the three monosaccharides without destruction of Neu5Ac or conversion of GlcNAc/GalNAc to GlcN/GalN in the hydrolysis procedure, the pivotal parameters affecting the liberation of N-acetylhexosamines/Neu5Ac from sample were investigated with response surface methodology (RSM). Under the optimized condition, maximum yield was obtained. The effects of key parameters on derivatization, separation and detection were also investigated. At optimized conditions, three monosaccharides were labeled fast and entirely, and all derivatives exhibited a good baseline resolution and high detection sensitivity. The developed method was linear over the calibration range 0.25-12μM, with R(2)>0.9991. The detection limits of the method were between 0.48 and 2.01pmol. Intra- and inter-day precisions for the three monosaccharides (GlcNAc, GalNAc and Neu5Ac) were found to be in the range of 3.07-4.02% and 3.69-4.67%, respectively. Individual monosaccharide recovery from spiked milk was in the range of 81%-97%. The sensitivity of the method, the facility of the derivatization procedure and the reliability of the hydrolysis conditions suggest the proposed method has a high potential for utilization in routine trace N-acetylhexosamines and Neu5Ac analysis in biological samples. PMID:26751589

  1. Human jagged polypeptide, encoding nucleic acids and methods of use

    DOEpatents

    Li, Linheng; Hood, Leroy

    2000-01-01

    The present invention provides an isolated polypeptide exhibiting substantially the same amino acid sequence as JAGGED, or an active fragment thereof, provided that the polypeptide does not have the amino acid sequence of SEQ ID NO:5 or SEQ ID NO:6. The invention further provides an isolated nucleic acid molecule containing a nucleotide sequence encoding substantially the same amino acid sequence as JAGGED, or an active fragment thereof, provided that the nucleotide sequence does not encode the amino acid sequence of SEQ ID NO:5 or SEQ ID NO:6. Also provided herein is a method of inhibiting differentiation of hematopoietic progenitor cells by contacting the progenitor cells with an isolated JAGGED polypeptide, or active fragment thereof. The invention additionally provides a method of diagnosing Alagille Syndrome in an individual. The method consists of detecting an Alagille Syndrome disease-associated mutation linked to a JAGGED locus.

  2. Method of detecting genetic translocations identified with chromosomal abnormalities

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel; Tkachuk, Douglas

    2001-01-01

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  3. Method of detecting genetic deletions identified with chromosomal abnormalities

    DOEpatents

    Gray, Joe W; Pinkel, Daniel; Tkachuk, Douglas

    2013-11-26

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyzes. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acids probes are typically of a complexity greater tha 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particlularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar ut genetically different diseases, and for many prognostic and diagnostic applications.

  4. Detection and isolation of nucleic acid sequences using a bifunctional hybridization probe

    DOEpatents

    Lucas, Joe N.; Straume, Tore; Bogen, Kenneth T.

    2000-01-01

    A method for detecting and isolating a target sequence in a sample of nucleic acids is provided using a bifunctional hybridization probe capable of hybridizing to the target sequence that includes a detectable marker and a first complexing agent capable of forming a binding pair with a second complexing agent. A kit is also provided for detecting a target sequence in a sample of nucleic acids using a bifunctional hybridization probe according to this method.

  5. Nucleic acid sequence detection using multiplexed oligonucleotide PCR

    DOEpatents

    Nolan, John P.; White, P. Scott

    2006-12-26

    Methods for rapidly detecting single or multiple sequence alleles in a sample nucleic acid are described. Provided are all of the oligonucleotide pairs capable of annealing specifically to a target allele and discriminating among possible sequences thereof, and ligating to each other to form an oligonucleotide complex when a particular sequence feature is present (or, alternatively, absent) in the sample nucleic acid. The design of each oligonucleotide pair permits the subsequent high-level PCR amplification of a specific amplicon when the oligonucleotide complex is formed, but not when the oligonucleotide complex is not formed. The presence or absence of the specific amplicon is used to detect the allele. Detection of the specific amplicon may be achieved using a variety of methods well known in the art, including without limitation, oligonucleotide capture onto DNA chips or microarrays, oligonucleotide capture onto beads or microspheres, electrophoresis, and mass spectrometry. Various labels and address-capture tags may be employed in the amplicon detection step of multiplexed assays, as further described herein.

  6. Detection of boronic acid derivatives in cells using a fluorescent sensor.

    PubMed

    Hattori, Yoshihide; Ishimura, Miki; Ohta, Youichirou; Takenaka, Hiroshi; Watanabe, Tsubasa; Tanaka, Hiroki; Ono, Koji; Kirihata, Mitsunori

    2015-07-01

    The detection of boron-containing compounds requires very expensive facilities and/or tedious sample pretreatments. In an effort to develop a convenient detection method for boronic acid derivatives, boron chelating-ligands were synthesized for use as fluorescent sensors. In this paper, the synthesis and properties of fluorescent sensors for boronic acid derivatives are reported. PMID:26022725

  7. Method for sequencing nucleic acid molecules

    DOEpatents

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2006-05-30

    The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

  8. Method for sequencing nucleic acid molecules

    DOEpatents

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2006-06-06

    The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

  9. Particle detection systems and methods

    DOEpatents

    Morris, Christopher L.; Makela, Mark F.

    2010-05-11

    Techniques, apparatus and systems for detecting particles such as muons and neutrons. In one implementation, a particle detection system employs a plurality of drift cells, which can be for example sealed gas-filled drift tubes, arranged on sides of a volume to be scanned to track incoming and outgoing charged particles, such as cosmic ray-produced muons. The drift cells can include a neutron sensitive medium to enable concurrent counting of neutrons. The system can selectively detect devices or materials, such as iron, lead, gold, uranium, plutonium, and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can concurrently detect any unshielded neutron sources occupying the volume from neutrons emitted therefrom. If necessary, the drift cells can be used to also detect gamma rays. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

  10. Sensitive Real-Time PCR Detection of Pathogenic Leptospira spp. and a Comparison of Nucleic Acid Amplification Methods for the Diagnosis of Leptospirosis

    PubMed Central

    Waggoner, Jesse J.; Balassiano, Ilana; Abeynayake, Janaki; Sahoo, Malaya K.; Mohamed-Hadley, Alisha; Liu, Yuanyuan; Vital-Brazil, Juliana Magalhães; Pinsky, Benjamin A.

    2014-01-01

    Background Bacteria of the genus Leptospira, the causative agents of leptospirosis, are categorized into pathogenic and non-pathogenic species. However, the benefit of using a clinical diagnostic that is specific for pathogenic species remains unclear. In this study, we present the development of a real-time PCR (rtPCR) for the detection of pathogenic Leptospira (the pathogenic rtPCR), and we perform a comparison of the pathogenic rtPCR with a published assay that detects all Leptospira species [the undifferentiated febrile illness (UFI) assay] and a reference 16S Leptospira rtPCR, which was originally designed to detect pathogenic species. Methodology/Principal Findings For the pathogenic rtPCR, a new hydrolysis probe was designed for use with primers from the UFI assay, which targets the 16S gene. The pathogenic rtPCR detected Leptospira DNA in 37/37 cultured isolates from 5 pathogenic and one intermediate species. Two strains of the non-pathogenic L. biflexa produced no signal. Clinical samples from 65 patients with suspected leptospirosis were then tested using the pathogenic rtPCR and a reference Leptospira 16S rtPCR. All 65 samples had tested positive for Leptospira using the UFI assay; 62 (95.4%) samples tested positive using the pathogenic rtPCR (p = 0.24). Only 24 (36.9%) samples tested positive in the reference 16S rtPCR (p<0.0001 for comparison with the pathogenic rtPCR and UFI assays). Amplicon sequencing confirmed the detection of pathogenic Leptospira species in 49/50 cases, including 3 cases that were only detected using the UFI assay. Conclusions/Significance The pathogenic rtPCR displayed similar sensitivity to the UFI assay when testing clinical specimens with no difference in specificity. Both assays proved significantly more sensitive than a real-time molecular test used for comparison. Future studies are needed to investigate the clinical and epidemiologic significance of more sensitive Leptospira detection using these tests. PMID:25379890

  11. [Laboratory methods for detection and identification of biological pathogens].

    PubMed

    Bar-Haim, Erez; Aran, Adi; Marcus, Nir; Finkelstein, Arseny; Amsalem, Yoram; Yehezkeli, Yoav

    2005-05-01

    Laboratory detection and recognition methods of infectious diseases agents have developed markedly in recent years, following the proliferation of nucleic acid and immuno-based detection technologies. The present review summarizes the state of the art in current biorecognition methods: antigenic identification, genetic identification such as PCR, RFLP and FISH, protemics and mass spectrometry. For each method we have specified the technology and qualification required, time to result, specifity and sensitivity, while emphasizing the advantages and disadvantages of using each method for the detection of a given pathogen. Nucleic acid-based detection is more specific and sensitive than immunological-based detection, while the latter is simpler and expected to further development with the improvements in the affinity, specifity and mass production of new immunoglobulins. Protein-based detection methods have an advantage comparing to nucleic acid identification: the presence of the protein approves that the tested gene is functional. Mass spectrometry enables simultaneous detections of multiple proteins and thus holds a promise for new technical developments with a vast array of applications. Most physicians do not practice biodetection technologies in their every day routine, but encounter those terms in their clinical and academic work. The review aims to display basic information in this field in order to enable a common language with basic science specialists. PMID:15931898

  12. Method For Detecting Biological Agents

    DOEpatents

    Chen, Liaohai; McBranch, Duncan W.; Wang, Hsing-Lin; Whitten, David G.

    2005-12-27

    A sensor is provided including a polymer capable of having an alterable measurable property from the group of luminescence and electrical conductivity, the polymer having an intermediate combination of a recognition element, a tethering element and a property-altering element bound thereto and capable of altering the measurable property, the intermediate combination adapted for subsequent separation from the polymer upon exposure to an agent having an affinity for binding to the recognition element whereupon the separation of the intermediate combination from the polymer results in a detectable change in the alterable measurable property, and, detecting said detectable change in the alterable measurable property.

  13. A rapid method for preparation of nucleic acid extracts from potato psyllids for detection of 'Candidatus Liberibacter solancearum' and molecular analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A rapid method has been developed and validated for PCR analysis of potato psyllids for Candidatus Liberibacter solanacearum (Lso), the causal agent of zebra chip disease of potatoes. The method is also suitable for PCR amplification and high resolution melting analysis of the cytochrome oxidase I ...

  14. Apparatus for point-of-care detection of nucleic acid in a sample

    DOEpatents

    Bearinger, Jane P.; Dugan, Lawrence C.

    2016-04-19

    Provided herein are methods and apparatus for detecting a target nucleic acid in a sample and related methods and apparatus for diagnosing a condition in an individual. The condition is associated with presence of nucleic acid produced by certain pathogens in the individual.

  15. Human pathogenic Cryptosporidium species bioanalytical detection method with single oocyst detection capability.

    PubMed

    Connelly, John T; Nugen, Sam R; Borejsza-Wysocki, Wlodek; Durst, Richard A; Montagna, Richard A; Baeumner, Antje J

    2008-05-01

    A bioanalytical detection method for specific detection of viable human pathogenic Cryptosporidium species, C. parvum, C. hominis, and C. meleagridis is described. Oocysts were isolated from water samples via immunomagnetic separation, and mRNA was extracted with oligo-dT magnetic beads, amplified using nucleic acid sequence-based amplification (NASBA), and then detected in a nucleic acid hybridization lateral flow assay. The amplified target sequence employed was hsp70 mRNA, production of which is stimulated via a brief heat shock. The described method was capable of detecting one oocyst in 10 μL using flow-cytometer-counted samples. Only viable oocysts were detected, as confirmed using 4',6-diamidino-2-phenylindole and propidium iodide (DAPI/PI) staining. The detection system was challenged by detecting oocysts in the presence of large numbers of common waterborne microorganisms and packed pellet material filtered from environmental water samples. When the method was compared with EPA Method 1622 for C. parvum detection, highly comparable results were obtained. Since the described detection system yields unambiguous results within 4.5 h, it is an ideal method for monitoring the safety of drinking water. PMID:18311563

  16. Improved flaw-detection method

    NASA Technical Reports Server (NTRS)

    Platt, R. J., Jr.

    1980-01-01

    Holographic detection of unbonded or delaminated surfaces of materials and structures is improved by using helium instead of air in vacuum test chamber. Helium has index of refraction closer to vacuum (unity) than air. Therefore changes in chamber pressure during test do not alter index of refraction as much as they do with air. With air, much of detail is lost, particularly in curved areas.

  17. Methods for analyzing nucleic acid sequences

    DOEpatents

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2011-05-17

    The present invention is directed to a method of sequencing a target nucleic acid. The method provides a complex comprising a polymerase enzyme, a target nucleic acid molecule, and a primer, wherein the complex is immobilized on a support Fluorescent label is attached to a terminal phosphate group of the nucleotide or nucleotide analog. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The time duration of the signal from labeled nucleotides or nucleotide analogs that become incorporated is distinguished from freely diffusing labels by a longer retention in the observation volume for the nucleotides or nucleotide analogs that become incorporated than for the freely diffusing labels.

  18. Nucleic Acid-Based Approaches for Detection of Viral Hepatitis

    PubMed Central

    Behzadi, Payam; Ranjbar, Reza; Alavian, Seyed Moayed

    2014-01-01

    Context: To determining suitable nucleic acid diagnostics for individual viral hepatitis agent, an extensive search using related keywords was done in major medical library and data were collected, categorized, and summarized in different sections. Results: Various types of molecular biology tools can be used to detect and quantify viral genomic elements and analyze the sequences. These molecular assays are proper technologies for rapidly detecting viral agents with high accuracy, high sensitivity, and high specificity. Nonetheless, the application of each diagnostic method is completely dependent on viral agent. Conclusions: Despite rapidity, automation, accuracy, cost-effectiveness, high sensitivity, and high specificity of molecular techniques, each type of molecular technology has its own advantages and disadvantages. PMID:25789132

  19. Phenolic acid esterases, coding sequences and methods

    DOEpatents

    Blum, David L.; Kataeva, Irina; Li, Xin-Liang; Ljungdahl, Lars G.

    2002-01-01

    Described herein are four phenolic acid esterases, three of which correspond to domains of previously unknown function within bacterial xylanases, from XynY and XynZ of Clostridium thermocellum and from a xylanase of Ruminococcus. The fourth specifically exemplified xylanase is a protein encoded within the genome of Orpinomyces PC-2. The amino acids of these polypeptides and nucleotide sequences encoding them are provided. Recombinant host cells, expression vectors and methods for the recombinant production of phenolic acid esterases are also provided.

  20. Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection.

    PubMed

    Mattila, Pirjo; Kumpulainen, Jorma

    2002-06-19

    A high-performance liquid chromatographic (HPLC) method with diode-array detection (DAD) was used to identify and quantify free and total phenolic acids (m-hydroxybenzoic acid, p-hydroxybenzoic acid, protocatechuic acid, gallic acid, vanillic acid, syringic acid, o-coumaric acid, m-coumaric acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, chlorogenic acid, and ellagic acid) in plant foods. Free phenolic acids were extracted with a mixture of methanol and 10% acetic acid. Bound phenolic acids were liberated using first alkaline and then acid hydrolysis followed by extraction with diethyl ether/ethyl acetate (1:1). All fractions were quantified separately by HPLC. After HPLC quantification, results of alkali and acid hydrolysates were calculated to represent total phenolic acids. Ellagic acid was quantified separately after long (20 h) acid hydrolysis. The methods developed were effective for the determination of phenolic acids in plant foods. DAD response was linear for all phenolic acids within the ranges evaluated, with correlation coefficients exceeding 0.999. Coefficients of variation for 4-8 sample replicates were consistently below 10%. Recovery tests of phenolic acids were performed for every hydrolysis condition using several samples. Recoveries were generally good (mean >90%) with the exceptions of gallic acid and, in some cases, caffeic acid samples. PMID:12059140

  1. A GC-ECD method for estimation of free and bound amino acids, gamma-aminobutyric acid, salicylic acid, and acetyl salicylic acid from Solanum lycopersicum (L.).

    PubMed

    Meher, Hari Charan; Gajbhiye, Vijay T; Singh, Ghanendra

    2011-01-01

    A gas chromatograph with electron capture detection method for estimation of selected metabolites--amino acids (free and bound), gamma-aminobutyric acid (GABA), salicylic acid (SA), and acetyl salicylic acid (ASA) from tomato--is reported. The method is based on nitrophenylation of the metabolites by 1-fluoro-2, 4-dinitrobenzene under aqueous alkaline conditions to form dinitophenyl derivatives. The derivatives were stable under the operating conditions of GC. Analysis of bound amino acids comprised perchloric acid precipitation of protein, alkylation (carboxymethylation) with iodoacetic acid, vapor-phase hydrolysis, and derivatization with 1-fluoro-2,4-dinitrobenzene in that order. The metabolites were resolved in 35 min, using a temperature-programmed run. The method is rapid, sensitive, and precise. It easily measured the typical amino acids (aspartate, asparagine, glutamate, glutamine, alanine, leucine, lysine, and phenylalanine) used for identification and quantification of a protein, resolved amino acids of the same mass (leucine and isoleucine), satisfactorily measured sulfur amino acid (methionine, cystine, and cysteine), and quantified GABA, SA, and ASA, as well. The developed method was validated for specificity, linearity, and precision. It has been applied and recommended for estimation of 25 metabolites from Solanum lycopersicum (L.). PMID:21391500

  2. Methodology for detecting residual phosphoric acid in polybenzoxazole fibers.

    PubMed

    Park, Eun Su; Sieber, John; Guttman, Charles; Rice, Kirk; Flynn, Kathleen; Watson, Stephanie; Holmes, Gale

    2009-12-01

    Because of the premature failure of in-service soft-body armor containing the ballistic fiber poly[(benzo-[1,2-d:5,4-d']-benzoxazole-2,6-diyl)-1,4-phenylene] (PBO), the Office of Law Enforcement Standards (OLES) at the National Institute of Standards and Technology (NIST) initiated a research program to investigate the reasons for this failure and to develop testing methodologies and protocols to ensure that these types of failures do not reoccur. In a report that focused on the stability of the benzoxazole ring that is characteristic of PBO fibers, Holmes, G. A.; Rice, K.; Snyder, C. R. J. Mater. Sci. 2006, 41, 4105-4116, showed that the benzoxazole ring was susceptible to hydrolytic degradation under acid conditions. Because of the processing conditions for the fibers, it is suspected by many researchers that residual phosphoric acid may cause degradation of the benzoxazole ring resulting in a reduction of ballistic performance. Prior to this work, no definitive data have indicated the presence of phosphoric acid since the residual phosphorus is not easily extracted and the processed fibers are known to incorporate phosphorus containing processing aids. Methods to efficiently extract phosphorus from PBO are described in this article. Further, characterization determined that the majority of the extractable phosphorus in PBO was attributed to the octyldecyl phosphate processing aid with some phosphoric acid being detected. Analysis by matrix assisted laser desorption ionization of model PBO oligomers indicates that the nonextractable phosphorus is attached to the PBO polymer chain as a monoaryl phosphate ester. The response of model aryl phosphates to NaOH exposure indicates that monoaryl phosphate ester is stable to NaOH washes used in the manufacturing process to neutralize the phosphoric acid reaction medium and to extract residual phosphorus impurities. PMID:19899783

  3. Method of detecting sulfur dioxide

    DOEpatents

    Spicer, Leonard D.; Bennett, Dennis W.; Davis, Jon F.

    1985-01-01

    (CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy.

  4. Improved Detection of Polygalacturonase Activity due to Mucor piriformis with a Modified Dinitrosalicylic Acid Reagent.

    PubMed

    Wang, G; Michailides, T J; Bostock, R M

    1997-02-01

    ABSTRACT An assay for determination of galacturonic acid with 3,5-dinitrosalicylic acid was developed that substantially extends the linear range of detection compared to a previously published method with this reagent. In the improved assay, galacturonic acid was detected with a reagent containing 44 mM 3,5-dinitrosalicylic acid, 4 mM sodium sulfite, and 375 mM sodium hydroxide. The absorbance of the solution after reaction with galacturonic acid was determined at 575 nm and was linear at concentrations of galacturonic acid up to 50 mumol, with a lower limit of detection at ~400 nmol. The assay with the improved reagent could be performed in wavelength ranges from 550 to 575 nm, with higher sensitivity at the shorter wavelengths. The new reagent was used in routine assays of polygalacturonase activity in culture filtrates of the important postharvest fungal pathogen Mucor piriformis. PMID:18945136

  5. Method for Trace Oxygen Detection

    NASA Technical Reports Server (NTRS)

    Man, Kim Fung (Inventor); Boumsellek, Said (Inventor); Chutjian, Ara (Inventor)

    1997-01-01

    Trace levels of molecular oxygen are measured by introducing a gas containing the molecular oxygen into a target zone, and impacting the molecular oxygen in the target zone with electrons at the O(-) resonant energy level for dissociative electron attachment to produce O(-) ions. Preferably, the electrons have an energy of about 4 to about 10 eV. The amount of O(-) ions produced is measured, and is correlated with the molecular oxygen content in the target zone. The technique is effective for measuring levels of oxygen below 50 ppb. and even less than 1 ppb. The amount of O(-) can be measured in a quadrupole mass analyzer. Best results are obtained when the electrons have an energy of about 6 to about 8 eV. and preferably about 6.8 eV. The method can be used for other species by selecting the appropriate electron energy level.

  6. Method for detecting coliform organisms

    NASA Technical Reports Server (NTRS)

    Nishioka, K.; Nibley, D. A.; Jeffers, E. L.; Brooks, R. L. (Inventor)

    1983-01-01

    A method and apparatus are disclosed for determining the concentration of coliform bacteria in a sample. The sample containing the coliform bacteria is cultured in a liquid growth medium. The cultured bacteria produce hydrogen and the hydrogen is vented to a second cell containing a buffer solution in which the hydrogen dissolves. By measuring the potential change in the buffer solution caused by the hydrogen, as a function of time, the initial concentration of bacteria in the sample is determined. Alternatively, the potential change in the buffer solution can be compared with the potential change in the liquid growth medium to verify that the potential change in the liquid growth medium is produced primarily by the hydrogen gas produced by the coliform bacteria.

  7. Spectral analysis method for detecting an element

    DOEpatents

    Blackwood, Larry G [Idaho Falls, ID; Edwards, Andrew J [Idaho Falls, ID; Jewell, James K [Idaho Falls, ID; Reber, Edward L [Idaho Falls, ID; Seabury, Edward H [Idaho Falls, ID

    2008-02-12

    A method for detecting an element is described and which includes the steps of providing a gamma-ray spectrum which has a region of interest which corresponds with a small amount of an element to be detected; providing nonparametric assumptions about a shape of the gamma-ray spectrum in the region of interest, and which would indicate the presence of the element to be detected; and applying a statistical test to the shape of the gamma-ray spectrum based upon the nonparametric assumptions to detect the small amount of the element to be detected.

  8. Underground tank leak detection methods

    SciTech Connect

    Niaki, Shahzad; Broscious, J.A.

    1987-01-01

    In recent years, the increase in leaks from underground gasoline storage tanks has had a significant adverse environmental impact on the US. Current estimates from government and industry sources are that between 1.5 to 3.5 million underground storage tanks exist in the nation. Estimates of the number of leaking tanks range from 75,000 to 100,000; and 350,000 others may develop leaks within the next five years. The 1983 National Petroleum News Factbook Issue forecasts the existence of approximately 140,000 gasoline service stations in the US at the end of 1983. New York State estimates that 19% of its 83,000 active underground gasoline tanks are now leaking. Maine estimates that 25% of its 1,600 retail gasoline underground tanks are leaking approximately 11 million gallons yearly. In Michigan 39% of ground water contamination incidents are attributed to storage tanks. One of the primary causes of tank leakage is corrosion of the storage tanks. Product loss from leaking tanks may cause an adverse effect on the environment, endanger lives, reduce income, and require the expenditure of millions of dollars for cleanup. To prevent or reduce the adverse effects of gasoline leakage, an accurate method must be used to determine whether or not an underground tank is leaking.

  9. Spectral methods to detect surface mines

    NASA Astrophysics Data System (ADS)

    Winter, Edwin M.; Schatten Silvious, Miranda

    2008-04-01

    Over the past five years, advances have been made in the spectral detection of surface mines under minefield detection programs at the U. S. Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD). The problem of detecting surface land mines ranges from the relatively simple, the detection of large anti-vehicle mines on bare soil, to the very difficult, the detection of anti-personnel mines in thick vegetation. While spatial and spectral approaches can be applied to the detection of surface mines, spatial-only detection requires many pixels-on-target such that the mine is actually imaged and shape-based features can be exploited. This method is unreliable in vegetated areas because only part of the mine may be exposed, while spectral detection is possible without the mine being resolved. At NVESD, hyperspectral and multi-spectral sensors throughout the reflection and thermal spectral regimes have been applied to the mine detection problem. Data has been collected on mines in forest and desert regions and algorithms have been developed both to detect the mines as anomalies and to detect the mines based on their spectral signature. In addition to the detection of individual mines, algorithms have been developed to exploit the similarities of mines in a minefield to improve their detection probability. In this paper, the types of spectral data collected over the past five years will be summarized along with the advances in algorithm development.

  10. Detecting Microbial Nucleic Acids within Nematode Bodies: A Photo Essay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We developed a taxa-specific, fluorescence in situ hybridization (FISH) technique to localize microbial nucleic acids within nematode bodies. This technique involves hybridization of a nucleic acid probe to target microbial sequences. Hybridization is detected microscopically, as the probes have f...

  11. Radiometric method for the rapid detection of Leptospira organisms

    SciTech Connect

    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.

  12. A method to attenuate U(VI) mobility in acidic waste plumes using humic acids

    SciTech Connect

    Wan, J.; Dong, W.; Tokunaga, T.K.

    2011-02-01

    Acidic uranium (U) contaminated plumes have resulted from acid-extraction of plutonium during the Cold War and from U mining and milling operations. A sustainable method for in-situ immobilization of U under acidic conditions is not yet available. Here, we propose to use humic acids (HAs) for in-situ U immobilization in acidic waste plumes. Our laboratory batch experiments show that HA can adsorb onto aquifer sediments rapidly, strongly and practically irreversibly. Adding HA greatly enhanced U adsorption capacity to sediments at pH below 5.0. Our column experiments using historically contaminated sediments from the Savannah River Site under slow flow rates (120 and 12 m/y) show that desorption of U and HA were non-detectable over 100 pore-volumes of leaching with simulated acidic groundwaters. Upon HA-treatment, 99% of the contaminant [U] was immobilized at pH < 4.5, compared to 5% and 58% immobilized in the control columns at pH 3.5 and 4.5, respectively. These results demonstrated that HA-treatment is a promising in-situ remediation method for acidic U waste plumes. As a remediation reagent, HAs are resistant to biodegradation, cost effective, nontoxic, and easily introducible to the subsurface.

  13. Method and apparatus for staining immobilized nucleic acids

    DOEpatents

    Ramsey, J. Michael; Foote, Robert S.; Jacobson, Stephen C.

    2000-01-01

    A method for staining immobilized nucleic acids includes the steps of affixing DNA probes to a solid substrate, moving target DNA material into proximity with the DNA probes, whereby the target DNA hybridized with specific ones of the DNA probes, and moving a fluorescent dye into proximity with the hybridized target DNA, whereby the fluorescent dye binds to the hybridized DNA to enable subsequent detection of fluorescence.

  14. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    PubMed Central

    Lui, Clarissa; Cady, Nathaniel C.; Batt, Carl A.

    2009-01-01

    The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform. PMID:22412335

  15. Method and apparatus for detecting halogenated hydrocarbons

    DOEpatents

    Monagle, Matthew; Coogan, John J.

    1997-01-01

    A halogenated hydrocarbon (HHC) detector is formed from a silent discharge (also called a dielectric barrier discharge) plasma generator. A silent discharge plasma device receives a gas sample that may contain one or more HHCs and produces free radicals and excited electrons for oxidizing the HHCs in the gas sample to produce water, carbon dioxide, and an acid including halogens in the HHCs. A detector is used to sensitively detect the presence of the acid. A conductivity cell detector combines the oxidation products with a solvent where dissociation of the acid increases the conductivity of the solvent. The conductivity cell output signal is then functionally related to the presence of HHCs in the gas sample. Other detectors include electrochemical cells, infrared spectrometers, and negative ion mobility spectrometers.

  16. Bioluminescent bioreporter integrated circuit detection methods

    DOEpatents

    Simpson, Michael L.; Paulus, Michael J.; Sayler, Gary S.; Applegate, Bruce M.; Ripp, Steven A.

    2005-06-14

    Disclosed are monolithic bioelectronic devices comprising a bioreporter and an OASIC. These bioluminescent bioreporter integrated circuit are useful in detecting substances such as pollutants, explosives, and heavy-metals residing in inhospitable areas such as groundwater, industrial process vessels, and battlefields. Also disclosed are methods and apparatus for detection of particular analytes, including ammonia and estrogen compounds.

  17. CURRENT METHODS FOR DETECTION OF CRYPTOSPORIDIUM SPECIES

    EPA Science Inventory

    Current methods for detecting protozoa in water produce results that are highly variable. It is difficult to determine if the methods themselves, or the procedures for testing these methods, are the source of the variability. If testing procedures are responsible for high varia...

  18. Acetic acid chromoendoscopy: Improving neoplasia detection in Barrett's esophagus

    PubMed Central

    Chedgy, Fergus J Q; Subramaniam, Sharmila; Kandiah, Kesavan; Thayalasekaran, Sreedhari; Bhandari, Pradeep

    2016-01-01

    Barrett’s esophagus (BE) is an important condition given its significant premalignant potential and dismal five-year survival outcomes of advanced esophageal adenocarcinoma. It is therefore suggested that patients with a diagnosis of BE undergo regular surveillance in order to pick up dysplasia at an earlier stage to improve survival. Current “gold-standard” surveillance protocols suggest targeted biopsy of visible lesions followed by four quadrant random biopsies every 2 cm. However, this method of Barrett’s surveillance is fraught with poor endoscopist compliance as the procedures are time consuming and poorly tolerated by patients. There are also significant miss-rates with this technique for the detection of neoplasia as only 13% of early neoplastic lesions appear as visible nodules. Despite improvements in endoscope resolution these problems persist. Chromoendoscopy is an extremely useful adjunct to enhance mucosal visualization and characterization of Barrett’s mucosa. Acetic acid chromoendoscopy (AAC) is a simple, non-proprietary technique that can significantly improve neoplasia detection rates. This topic highlight summarizes the current evidence base behind AAC for the detection of neoplasia in BE and provides an insight into the direction of travel for further research in this area. PMID:27433088

  19. Acetic acid chromoendoscopy: Improving neoplasia detection in Barrett's esophagus.

    PubMed

    Chedgy, Fergus J Q; Subramaniam, Sharmila; Kandiah, Kesavan; Thayalasekaran, Sreedhari; Bhandari, Pradeep

    2016-07-01

    Barrett's esophagus (BE) is an important condition given its significant premalignant potential and dismal five-year survival outcomes of advanced esophageal adenocarcinoma. It is therefore suggested that patients with a diagnosis of BE undergo regular surveillance in order to pick up dysplasia at an earlier stage to improve survival. Current "gold-standard" surveillance protocols suggest targeted biopsy of visible lesions followed by four quadrant random biopsies every 2 cm. However, this method of Barrett's surveillance is fraught with poor endoscopist compliance as the procedures are time consuming and poorly tolerated by patients. There are also significant miss-rates with this technique for the detection of neoplasia as only 13% of early neoplastic lesions appear as visible nodules. Despite improvements in endoscope resolution these problems persist. Chromoendoscopy is an extremely useful adjunct to enhance mucosal visualization and characterization of Barrett's mucosa. Acetic acid chromoendoscopy (AAC) is a simple, non-proprietary technique that can significantly improve neoplasia detection rates. This topic highlight summarizes the current evidence base behind AAC for the detection of neoplasia in BE and provides an insight into the direction of travel for further research in this area. PMID:27433088

  20. Computational stoning method for surface defect detection

    NASA Astrophysics Data System (ADS)

    Ma, Ninshu; Zhu, Xinhai

    2013-12-01

    Surface defects on outer panels of automotive bodies must be controlled in order to improve the surface quality. The detection and quantitative evaluation of surface defects are quite difficult because the deflection of surface defects is very small. One of detecting methods for surface defects used in factories is a stoning method in which a stone block is moved on the surface of a stamped panel. The computational stoning method was developed to detect surface low defect by authors based on a geometry contact algorithm between a stone block and a stamped panel. If the surface is convex, the stone block always contacts with the convex surface of a stamped panel and the contact gap between them is zero. If there is a surface low, the stone block does not contact to the surface and the contact gap can be computed based on contact algorithm. The convex surface defect can also be detected by applying computational stoning method to the back surface of a stamped panel. By performing two way stoning computations from both the normal surface and the back surface, not only the depth of surface low defect but also the height of convex surface defect can be detected. The surface low defect and convex surface defect can also be detected through multi-directions. Surface defects on the handle emboss of outer panels were accurately detected using the computational stoning method and compared with the real shape. A very good accuracy was obtained.

  1. Methods for the detection of marine toxins

    SciTech Connect

    Wekell, M.M.; Manger, R.M.; Hadley, S.W.; Hungerford, J.M.

    1995-12-01

    Toxic materials have been dumped into the seas from waste streams and other pollutant sources such as runoff, etc. For protection of public health, it is essential that rapid, reliable and simple methods exist to detect marine toxins in seafoods. In addition, it is necessary to develop methods requiring a minimum of test material. Pure standards for many of the marine toxins are scarce. Reduced sample requirements extend the utility of detection methods in research and forensic applications as well. In the past, there was much reliance on the animal bioassay; however, this dependence hopefully will be reduced as newer instrumental techniques (chromatographic, mass spectrometric, electrophoretic), biochemical (immunochemical, receptor site assay), and cell bioassay methods are developed with a higher degree of precision and specificity. It is beneficial that a multiplicity of methods be available to detect marine toxins in seafoods. Each method has unique advantages and disadvantages.

  2. Apparatus and methods for detecting chemical permeation

    DOEpatents

    Vo-Dinh, Tuan

    1994-01-01

    Apparatus and methods for detecting the permeation of hazardous or toxic chemicals through protective clothing are disclosed. The hazardous or toxic chemicals of interest do not possess the spectral characteristic of luminescence. The apparatus and methods utilize a spectrochemical modification technique to detect the luminescence quenching of an indicator compound which upon permeation of the chemical through the protective clothing, the indicator is exposed to the chemical, thus indicating chemical permeation.

  3. Analytic sequential methods for detecting network intrusions

    NASA Astrophysics Data System (ADS)

    Chen, Xinjia; Walker, Ernest

    2014-05-01

    In this paper, we propose an analytic sequential methods for detecting port-scan attackers which routinely perform random "portscans" of IP addresses to find vulnerable servers to compromise. In addition to rigorously control the probability of falsely implicating benign remote hosts as malicious, our method performs significantly faster than other current solutions. We have developed explicit formulae for quick determination of the parameters of the new detection algorithm.

  4. Method for analyzing nucleic acids by means of a substrate having a microchannel structure containing immobilized nucleic acid probes

    DOEpatents

    Ramsey, J. Michael; Foote, Robert S.

    2002-01-01

    A method and apparatus for analyzing nucleic acids includes immobilizing nucleic probes at specific sites within a microchannel structure and moving target nucleic acids into proximity to the probes in order to allow hybridization and fluorescence detection of specific target sequences.

  5. Method for analyzing nucleic acids by means of a substrate having a microchannel structure containing immobilized nucleic acid probes

    DOEpatents

    Ramsey, J. Michael; Foote, Robert S.

    2003-12-09

    A method and apparatus for analyzing nucleic acids includes immobilizing nucleic probes at specific sites within a microchannel structure and moving target nucleic acids into proximity to the probes in order to allow hybridization and fluorescence detection of specific target sequences.

  6. Detection of folic acid protein in human serum using reduced graphene oxide electrodes modified by folic-acid.

    PubMed

    He, Lijie; Wang, Qian; Mandler, Daniel; Li, Musen; Boukherroub, Rabah; Szunerits, Sabine

    2016-01-15

    The detection of disease markers is considered an important step for early diagnosis of cancer. We design in this work a novel electrochemical sensing platform for the sensitive and selective detection of folic acid protein (FP). The platform is fabricated by electrophoretic deposition (EPD) of reduced graphene oxide (rGO) onto a gold electrode and post-functionalization of rGO with folic acid. Upon FP binding, a significant current decrease can be measured using differential pulse voltammetry (DPV). Using this scheme, a detection limit of 1pM is achieved. Importantly, the method also allows the detection of FP in serum being thus an appealing approach for the sensitive detection of biomarkers in clinical samples. PMID:26342582

  7. Radionuclide detection devices and associated methods

    SciTech Connect

    Mann, Nicholas R.; Lister, Tedd E.; Tranter, Troy J.

    2011-03-08

    Radionuclide detection devices comprise a fluid cell comprising a flow channel for a fluid stream. A radionuclide collector is positioned within the flow channel and configured to concentrate one or more radionuclides from the fluid stream onto at least a portion of the radionuclide collector. A scintillator for generating scintillation pulses responsive to an occurrence of a decay event is positioned proximate at least a portion of the radionuclide collector and adjacent to a detection system for detecting the scintillation pulses. Methods of selectively detecting a radionuclide are also provided.

  8. Method for predicting peptide detection in mass spectrometry

    DOEpatents

    Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA

    2010-07-13

    A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.

  9. Coverage methods for early groundwater contamination detection.

    PubMed

    Nunes, Luís Miguel; da Conceição Cunha, Maria; Ribeiro, Luís

    2013-05-01

    A method based on space-filling coverage designs to optimize groundwater monitoring networks for plume detection and quantification is proposed. Space-filling objective functions are then compared with more classical functions. The method was applied to a hypothetical case-study with 160 candidate locations, resulting in final optimal design monitoring networks with 40 locations. Results show that the method is superior to those based strictly on the probability of contamination detection for quantifying maximum and mean values. In the light of these results fractal properties of space-filling coverage methods and of simulated annealing are also discussed. PMID:23435904

  10. Method for remote detection of trace contaminants

    DOEpatents

    Simonson, Robert J.; Hance, Bradley G.

    2003-09-09

    A method for remote detection of trace contaminants in a target area comprises applying sensor particles that preconcentrate the trace contaminant to the target area and detecting the contaminant-sensitive fluorescence from the sensor particles. The sensor particles can have contaminant-sensitive and contaminant-insensitive fluorescent compounds to enable the determination of the amount of trace contaminant present in the target are by relative comparison of the emission of the fluorescent compounds by a local or remote fluorescence detector. The method can be used to remotely detect buried minefields.

  11. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, G.R.

    1994-09-06

    An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1 [times] 10[sup [minus]18] atm cc sec[sup [minus]1]. 2 figs.

  12. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, Ganapatic R.

    1994-01-01

    An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1.times.10.sup.-18 atm cc sec.sup.-1.

  13. Visual detection of Ebola virus using reverse transcription loop-mediated isothermal amplification combined with nucleic acid strip detection.

    PubMed

    Xu, Changping; Wang, Hualei; Jin, Hongli; Feng, Na; Zheng, Xuexing; Cao, Zengguo; Li, Ling; Wang, Jianzhong; Yan, Feihu; Wang, Lina; Chi, Hang; Gai, Weiwei; Wang, Chong; Zhao, Yongkun; Feng, Yan; Wang, Tiecheng; Gao, Yuwei; Lu, Yiyu; Yang, Songtao; Xia, Xianzhu

    2016-05-01

    Ebola virus (species Zaire ebolavirus) (EBOV) is highly virulent in humans. The largest recorded outbreak of Ebola hemorrhagic fever in West Africa to date was caused by EBOV. Therefore, it is necessary to develop a detection method for this virus that can be easily distributed and implemented. In the current study, we developed a visual assay that can detect EBOV-associated nucleic acids. This assay combines reverse transcription loop-mediated isothermal amplification and nucleic acid strip detection (RT-LAMP-NAD). Nucleic acid amplification can be achieved in a one-step process at a constant temperature (58 °C, 35 min), and the amplified products can be visualized within 2-5 min using a nucleic acid strip detection device. The assay is capable of detecting 30 copies of artificial EBOV glycoprotein (GP) RNA and RNA encoding EBOV GP from 10(2) TCID50 recombinant viral particles per ml with high specificity. Overall, the RT-LAMP-NAD method is simple and has high sensitivity and specificity; therefore, it is especially suitable for the rapid detection of EBOV in African regions. PMID:26831931

  14. Adaptive sequential methods for detecting network intrusions

    NASA Astrophysics Data System (ADS)

    Chen, Xinjia; Walker, Ernest

    2013-06-01

    In this paper, we propose new sequential methods for detecting port-scan attackers which routinely perform random "portscans" of IP addresses to find vulnerable servers to compromise. In addition to rigorously control the probability of falsely implicating benign remote hosts as malicious, our method performs significantly faster than other current solutions. Moreover, our method guarantees that the maximum amount of observational time is bounded. In contrast to the previous most effective method, Threshold Random Walk Algorithm, which is explicit and analytical in nature, our proposed algorithm involve parameters to be determined by numerical methods. We have introduced computational techniques such as iterative minimax optimization for quick determination of the parameters of the new detection algorithm. A framework of multi-valued decision for detecting portscanners and DoS attacks is also proposed.

  15. Detection of exogenous citric acid in fruit juices by stable isotope ratio analysis.

    PubMed

    Jamin, Eric; Martin, Frédérique; Santamaria-Fernandez, Rebeca; Lees, Michèle

    2005-06-29

    A new method has been developed for measuring the D/H ratio of the nonexchangeable sites of citric acid by isotope ratio mass spectrometry (IRMS). Pure citric acid is transformed into its calcium salt and subsequently analyzed by pyrolysis-IRMS. The citric acid isolated from authentic fruit juices (citrus, pineapple, and red fruits) systematically shows higher D/H values than its nonfruit counterpart produced by fermentation of various sugar sources. The discrimination obtained with this simplified method is similar to that obtained previously by applying site specific isotopic fractionation-nuclear magnetic resonance (SNIF-NMR) to an ester derivative of citric acid. The combination of carbon 13 and deuterium measurements of extracted citric acid is proposed as a routine method for an optimum detection of exogenous citric acid in all kinds of fruit juices. PMID:15969486

  16. Method for the production of dicarboxylic acids

    DOEpatents

    Nghiem, Nhuan Phu; Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    1999-01-01

    The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; c) controllably releasing oxygen to maintain the aerobic atmosphere; d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/L up to about 1 g/L; e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of .gtoreq.1 g/L; and g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism.

  17. Method for the production of dicarboxylic acids

    DOEpatents

    Nghiem, N.P.; Donnelly, M.; Millard, C.S.; Stols, L.

    1999-02-09

    The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of (a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; (b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; (c) controllably releasing oxygen to maintain the aerobic atmosphere; (d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/l up to about 1 g/l; (e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; (f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of {>=}1 g/l; and (g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism. 7 figs.

  18. Detection and isolation of nucleic acid sequences using competitive hybridization probes

    DOEpatents

    Lucas, Joe N.; Straume, Tore; Bogen, Kenneth T.

    1997-01-01

    A method for detecting a target nucleic acid sequence in a sample is provided using hybridization probes which competitively hybridize to a target nucleic acid. According to the method, a target nucleic acid sequence is hybridized to first and second hybridization probes which are complementary to overlapping portions of the target nucleic acid sequence, the first hybridization probe including a first complexing agent capable of forming a binding pair with a second complexing agent and the second hybridization probe including a detectable marker. The first complexing agent attached to the first hybridization probe is contacted with a second complexing agent, the second complexing agent being attached to a solid support such that when the first and second complexing agents are attached, target nucleic acid sequences hybridized to the first hybridization probe become immobilized on to the solid support. The immobilized target nucleic acids are then separated and detected by detecting the detectable marker attached to the second hybridization probe. A kit for performing the method is also provided.

  19. Detection and isolation of nucleic acid sequences using competitive hybridization probes

    DOEpatents

    Lucas, J.N.; Straume, T.; Bogen, K.T.

    1997-04-01

    A method for detecting a target nucleic acid sequence in a sample is provided using hybridization probes which competitively hybridize to a target nucleic acid. According to the method, a target nucleic acid sequence is hybridized to first and second hybridization probes which are complementary to overlapping portions of the target nucleic acid sequence, the first hybridization probe including a first complexing agent capable of forming a binding pair with a second complexing agent and the second hybridization probe including a detectable marker. The first complexing agent attached to the first hybridization probe is contacted with a second complexing agent, the second complexing agent being attached to a solid support such that when the first and second complexing agents are attached, target nucleic acid sequences hybridized to the first hybridization probe become immobilized on to the solid support. The immobilized target nucleic acids are then separated and detected by detecting the detectable marker attached to the second hybridization probe. A kit for performing the method is also provided. 7 figs.

  20. An enhanced Monte Carlo outlier detection method.

    PubMed

    Zhang, Liangxiao; Li, Peiwu; Mao, Jin; Ma, Fei; Ding, Xiaoxia; Zhang, Qi

    2015-09-30

    Outlier detection is crucial in building a highly predictive model. In this study, we proposed an enhanced Monte Carlo outlier detection method by establishing cross-prediction models based on determinate normal samples and analyzing the distribution of prediction errors individually for dubious samples. One simulated and three real datasets were used to illustrate and validate the performance of our method, and the results indicated that this method outperformed Monte Carlo outlier detection in outlier diagnosis. After these outliers were removed, the value of validation by Kovats retention indices and the root mean square error of prediction decreased from 3.195 to 1.655, and the average cross-validation prediction error decreased from 2.0341 to 1.2780. This method helps establish a good model by eliminating outliers. © 2015 Wiley Periodicals, Inc. PMID:26226927

  1. A Locked Nucleic Acid Probe Based on Selective Salt-Induced Effect Detects Single Nucleotide Polymorphisms

    PubMed Central

    Zhang, Jing; Wu, Huizhe; Chen, Qiuchen; Zhao, Pengfei; Zhao, Haishan; Yao, Weifan; Wei, Minjie

    2015-01-01

    Detection of single based genetic mutation by using oligonucleotide probes is one of the common methods of detecting single nucleotide polymorphisms at known loci. In this paper, we demonstrated a hybridization system which included a buffer solution that produced selective salt-induced effect and a locked nucleic acid modified 12 nt oligonucleotide probe. The hybridization system is suitable for hybridization under room temperature. By using magnetic nanoparticles as carriers for PCR products, the SNPs (MDR1 C3435T/A) from 45 volunteers were analyzed, and the results were consistent with the results from pyrophosphoric acid sequencing. The method presented in this paper differs from the traditional method of using molecular beacons to detect SNPs in that it is suitable for research institutions lacking real-time quantitative PCR detecting systems, to detect PCR products at room temperature. PMID:26347880

  2. A Novel Method of Line Detection using Image Integration Method

    NASA Astrophysics Data System (ADS)

    Lin, Daniel; Sun, Bo

    2015-03-01

    We developed a novel line detection algorithm based on image integration method. Hough Transformation uses spatial image gradient method to detect lines on an image. This is problematic because if the image has a region of high noise intensity, the gradient would point towards the noisy region . Denoising the noisy image requires an application of sophisticated noise reduction algorithm which increases computation complexity. Our algorithm can remedy this problem by averaging the pixels around the image region of interest. We were able to detect collagen fiber lines on an image produced by confocal microscope.

  3. Method of Fault Detection and Rerouting

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J. (Inventor); Gibson, Tracy L. (Inventor); Lewis, Mark E. (Inventor)

    2013-01-01

    A system and method for detecting damage in an electrical wire, including delivering at least one test electrical signal to an outer electrically conductive material in a continuous or non-continuous layer covering an electrically insulative material layer that covers an electrically conductive wire core. Detecting the test electrical signals in the outer conductive material layer to obtain data that is processed to identify damage in the outer electrically conductive material layer.

  4. Automated macromolecular crystal detection system and method

    DOEpatents

    Christian, Allen T.; Segelke, Brent; Rupp, Bernard; Toppani, Dominique

    2007-06-05

    An automated macromolecular method and system for detecting crystals in two-dimensional images, such as light microscopy images obtained from an array of crystallization screens. Edges are detected from the images by identifying local maxima of a phase congruency-based function associated with each image. The detected edges are segmented into discrete line segments, which are subsequently geometrically evaluated with respect to each other to identify any crystal-like qualities such as, for example, parallel lines, facing each other, similarity in length, and relative proximity. And from the evaluation a determination is made as to whether crystals are present in each image.

  5. Isothermal amplification detection of nucleic acids by a double-nicked beacon.

    PubMed

    Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

    2016-03-01

    Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use. PMID:26706801

  6. Detection of obstructive uropathy using 99m technetium diethylenetriaminepentaacetic acid

    SciTech Connect

    Powers, T.A.; Grove, R.B.; Bauriedel, J.K.; Orr, S.C.; Melton, R.E.; Bowenn, R.D.

    1980-11-01

    A simple, accurate test with no morbidity and effective for the detection of urinary tract obstruction in patients with normal and impaired renal function would be of significant clinical use. The ability of 99m technetium diethylenetriaminepentaacetic acid to detect the presence or absence of obstruction is evaluated. Obstructions were defined as abnormal retention of activity in the collecting system persisting in the delayed images. Diethylentriaminepentaacetic acid identified correctly 13 of 13 patients proved to have obstruction and 17 of 18 without obstruction. These data indicate a sensitivity of 100 percent, specificity of 94 percent and accuracy of 97 percent.

  7. Robert Feulgen Prize Lecture 1995. New approaches to in situ detection of nucleic acids.

    PubMed

    Thiry, M

    1995-08-01

    The present paper reviews recent results obtained by different molecular biology-based, immunocytological approaches to the localization and identification of nucleic acids in sections of biological material. Examples of sensitive, high-resolution detection methods for RNA, DNA or specialized DNA regions are presented. Special emphasis is placed on the potential values and limitations of these new methods. PMID:8536076

  8. Three Methods of Detection of Hydrazines

    NASA Technical Reports Server (NTRS)

    Griffin, Timothy; Berger, Cristina

    2010-01-01

    Three proposed methods for measuring trace quantities of hydrazines involve ionization and detection of hydrazine derivatives. These methods are intended to overcome the limitations of prior hydrazine- detection methods. Hydrazine (Hz), monomethylhydrazine (MMH), and unsymmetrical dimethylhydrazine (UDMH) are hypergolic fuels and are highly reactive, toxic, and corrosive. A capability to measure concentrations of hydrazines is desirable for detecting leaks and ensuring safety in aerospace settings and in some industrial settings in which these compounds are used. One of the properties (high reactivity) that make it desirable to detect trace amounts of hydrazines also makes it difficult to detect hydrazines and measure their concentrations accurately using prior methods: significant amounts are lost to thermal and catalytic decomposition prior to detection. Further complications arise from the sticky nature of hydrazines: Sample hydrazine molecules tend to become irreversibly adsorbed onto solid surfaces with which they come into contact during transport to detectors, giving rise to drift in detector responses. In each proposed method, the reactive, sticky nature of hydrazines would be turned to advantage by providing a suitably doped substrate surface with which the hydrazines would react. The resulting hydrazine derivatives would be sufficiently less sticky and sufficiently more stable so that fewer molecules would be lost to decomposition or adsorption during transport. Consequently, it would be possible to measure concentration with more sensitivity and less error than in prior techniques. The first proposed method calls for the use of a recently developed technique known as desorption electrospray ionization (DESI), in which a pneumatically assisted micro -electrospray at ambient pressure is directed at a surface of interest. In this case, the surface of interest would be that of a substrate described above.

  9. DimaSense™: A Novel Nucleic Acid Detection System

    SciTech Connect

    Stadler, A.

    2011-05-18

    Recently, we developed a suite of methods for the rational design and fabrication of well-defined nanoparticle architectures, including clusters using bio-encoded nanoscale building blocks and layer-by-layer stepwise assembly on a solid support. In particular, the Nano-Assembly platform using Encoded Solid Supports (NAESS) allows for controlled interactions, purification of side products, modularity of design, and the construction of complex nanoparticle architectures. This approach offers several advantages over the current art of designing nanoparticle clusters, which include the high-yield synthesis of desired architectures, a 'plug-and-play' design allowing for the introduction of a variety of sensing modalities, and ease of scalability in high-throughput and synthesis yield. As a utility proof of concept, we implemented our unique cluster fabrication platform to design gold nanoparticle dimers which are linked via a single-stranded DNA oligonucleotide recognition motif. The design of this motif is such that binding of complementary nucleic acids results in specific, selective and rapid dimer dissociation, which can be monitored by dynamic light scattering (DLS). We demonstrated single level mismatch selectivity using this approach. The limit of detection was determined to be 1011 molecules of synthetic target RNA or DNA within 30 minutes of incubation at 33 C. This detection limit is determined by the dimer's concentration which can be probed by currently used standard DLS instruments. We also demonstrated a specific detection of target RNA in a solution containing competing 1,000-fold excess of non-complementary DNA fragments, 10% BSA, and endonucleases. Molecular diagnostic companies, RNA-based technology developers, and personalized medicine companies have applications that could benefit from using DimaSense{trademark}. The technology represents a platform which enables the simple and reasonably inexpensive design and fabrication of highly selective genetic

  10. Tank leak detection using electrical resistance methods

    SciTech Connect

    Ramirez, A.; Daily, W.; Binley, A.; LaBrecque, D.

    1996-01-01

    Large volumes of hazardous liquids and high-level radioactive wastes are stored worldwide in surface and underground tanks. Frequently these tanks are found to leak, thereby resulting in not only a loss of stored inventory, but in contamination to soils and groundwater. It is important to develop a reliable method of detecting leaks before large quantities are emitted into the environment surround the tanks. Two field experiments were performed to evaluate the performance of electrical resistance tomography (ERT) as a leak detection method under metal underground storage tanks (UST). This paper provides a summary of the field experiments performed under a 15 m diameter steel tank mockup located at the Hanford Reservation.

  11. Apparatus and methods for detecting chemical permeation

    DOEpatents

    Vo-Dinh, T.

    1994-12-27

    Apparatus and methods for detecting the permeation of hazardous or toxic chemicals through protective clothing are disclosed. The hazardous or toxic chemicals of interest do not possess the spectral characteristic of luminescence. The apparatus and methods utilize a spectrochemical modification technique to detect the luminescence quenching of an indicator compound which upon permeation of the chemical through the protective clothing, the indicator is exposed to the chemical, thus indicating chemical permeation. The invention also relates to the fabrication of protective clothing materials. 13 figures.

  12. Application of HPLC with ELSD Detection for the Assessment of Azelaic Acid Impurities in Liposomal Formulation

    PubMed Central

    Han, Stanislaw; Karlowicz-Bodalska, Katarzyna; Ozimek, Lukasz

    2013-01-01

    In the course of research and development of a new pharmaceutical formulation of azelaic acid in the liposomal form, we developed a rapid and accurate method for the detection of impurities using high-performance liquid chromatography. A chromatographic column from Merck (Purospher Star RP C18, 250–4 mm (5 μm) was used in the assay, and the mobile phase gradient consisted of three phases: A—methanol : water (5 : 95) + 1.5% (v/v) acetic acid; B—water : methanol (5 : 95) + 1.5% (v/v) acetic acid; and C—chloroform. Detection of the impurities and the active substance was performed by an evaporative light-scattering detector. The method was validated for selectivity, system precision, method precision, limit of detection, and response rates. The proposed method can be used to detect impurities in the liposomal formulation of azelaic acid. The method enables separation of azelaic acid from the identified and unidentified impurities and from the excipients used in the drug form. PMID:24228008

  13. Rapid and enzyme-free nucleic acid detection based on exponential hairpin assembly in complex biological fluids.

    PubMed

    Ma, Cuiping; Zhang, Menghua; Chen, Shan; Liang, Chao; Shi, Chao

    2016-05-10

    Herein, we have developed a rapid and enzyme-free nucleic acid amplification detection method that combined the exponential self-assembly of four DNA hairpins and the FRET pair Cy3 and Cy5. This strategy was very ingenious and rapid, and could detect nucleic acids at concentrations as low as 10 pM in 15 min in biological fluids. PMID:27138054

  14. Novel methods for detecting buried explosive devices

    SciTech Connect

    Kercel, S.W.; Burlage, R.S.; Patek, D.R.; Smith, C.M.; Hibbs, A.D.; Rayner, T.J.

    1997-04-01

    Oak Ridge National Laboratory (ORNL) and Quantum Magnetics, Inc. (QM) are exploring novel landmine detection technologies. Technologies considered here include bioreporter bacteria, swept acoustic resonance, nuclear quadrupole resonance (NQR), and semiotic data fusion. Bioreporter bacteria look promising for third-world humanitarian applications; they are inexpensive, and deployment does not require high-tech methods. Swept acoustic resonance may be a useful adjunct to magnetometers in humanitarian demining. For military demining, NQR is a promising method for detecting explosive substances; of 50,000 substances that have been tested, none has an NQR signature that can be mistaken for RDX or TNT. For both military and commercial demining, sensor fusion entails two daunting tasks, identifying fusible features in both present-day and emerging technologies, and devising a fusion algorithm that runs in real-time on cheap hardware. Preliminary research in these areas is encouraging. A bioreporter bacterium for TNT detection is under development. Investigation has just started in swept acoustic resonance as an approach to a cheap mine detector for humanitarian use. Real-time wavelet processing appears to be a key to extending NQR bomb detection into mine detection, including TNT-based mines. Recent discoveries in semiotics may be the breakthrough that will lead to a robust fused detection scheme.

  15. Novel methods for detecting buried explosive devices

    NASA Astrophysics Data System (ADS)

    Kercel, Stephen W.; Burlage, Robert S.; Patek, David R.; Smith, Cyrus M.; Hibbs, Andrew D.; Rayner, Timothy J.

    1997-07-01

    Oak Ridge National Laboratory and Quantum Magnetics, Inc. are exploring novel landmine detection technologies. Technologies considered here include bioreporter bacteria, swept acoustic resonance, nuclear quadrupole resonance (NQR), and semiotic data fusion. Bioreporter bacteria look promising for third-world humanitarian applications; they are inexpensive, and deployment does not require high-tech methods. Swept acoustic resonance may be a useful adjunct to magnetometers in humanitarian demining. For military demining, NQR is a promising method for detecting explosive substances; of 50,000 substances that have been tested, one has an NQR signature that can be mistaken for RDX or TNT. For both military and commercial demining, sensor fusion entails two daunting tasks, identifying fusible features in both present-day and emerging technologies, and devising a fusion algorithm that runs in real-time on cheap hardware. Preliminary research in these areas is encouraging. A bioreporter bacterium for TNT detection is under development. Investigation has just started in swept acoustic resonance as an approach to a cheap mine detector for humanitarian use. Real-time wavelet processing appears to be a key to extending NQR bomb detection into mine detection, including TNT-based mines. Recent discoveries in semiotics may be the breakthrough that will lead to a robust fused detection scheme.

  16. Method of Identifying a Base in a Nucleic Acid

    DOEpatents

    Fodor, Stephen P. A.; Lipshutz, Robert J.; Huang, Xiaohua

    1999-01-01

    Devices and techniques for hybridization of nucleic acids and for determining the sequence of nucleic acids. Arrays of nucleic acids are formed by techniques, preferably high resolution, light-directed techniques. Positions of hybridization of a target nucleic acid are determined by, e.g., epifluorescence microscopy. Devices and techniques are proposed to determine the sequence of a target nucleic acid more efficiently and more quickly through such synthesis and detection techniques.

  17. Determination of aliphatic organic acids by high-performance liquid chromatography with pulsed electrochemical detection.

    PubMed

    Casella, Innocenzo G; Gatta, Maria

    2002-01-01

    A new ion exclusion HPLC procedure accomplished with a pulsed electrochemical detection for the determination of several common aliphatic acids is described. A triple-step waveform of the applied potentials, based on the formation/inhibition of PtOH species on the electrode surface, is successfully used for sensitive detection of several aliphatic acids in flowing systems avoiding pre- or postcolumn derivatization and/or cleanup procedures. Under optimal chromatographic conditions (i.e., 50 mM HClO(4)) the proposed method allowed detection limits between 0.5 and 7 microM for all investigated acids, and the dynamic linear range spanned generally over 1 or 2 orders of magnitude. Determination of citric, malic, tartaric, lactic, formic, and acetic acids in several foods and beverages was performed, in approximately 15 min, without the necessity of any sample pretreatment. PMID:11754537

  18. Flow cytometric detection method for DNA samples

    DOEpatents

    Nasarabadi,Shanavaz; Langlois, Richard G.; Venkateswaran, Kodumudi S.

    2011-07-05

    Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM.TM. on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA.TM., on the 5' end.

  19. Flow cytometric detection method for DNA samples

    DOEpatents

    Nasarabadi, Shanavaz; Langlois, Richard G.; Venkateswaran, Kodumudi S.

    2006-08-01

    Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM, on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA, on the 5' end.

  20. Graphdiyne as a promising material for detecting amino acids

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Gao, Pengfei; Guo, Lei; Zhang, Shengli

    2015-11-01

    The adsorption of glycine, glutamic acid, histidine and phenylalanine on single-layer graphdiyne/ graphene is investigated by ab initio calculations. The results show that for each amino acid molecule, the adsorption energy on graphdiyne is larger than the adsorption energy on graphene and dispersion interactions predominate in the adsorption. Molecular dynamics simulations reveal that at room temperature the amino acid molecules keep migrating and rotating on graphdiyne surface and induce fluctuation in graphdiyne bandgap. Additionally, the photon absorption spectra of graphdiyne-amino-acid systems are investigated. We uncover that the presence of amino acid molecules makes the photon absorption peaks of graphdiyne significantly depressed and shifted. Finally, quantum electronic transport properties of graphdiyne-amino-acid systems are compared with the transport properties of pure graphdiyne. We reveal that the amino acid molecules induce distinct changes in the electronic conductivity of graphdiyne. The results in this paper reveal that graphdiyne is a promising two-dimensional material for sensitively detecting amino acids and may potentially be used in biosensors.

  1. Graphdiyne as a promising material for detecting amino acids

    PubMed Central

    Chen, Xi; Gao, Pengfei; Guo, Lei; Zhang, Shengli

    2015-01-01

    The adsorption of glycine, glutamic acid, histidine and phenylalanine on single-layer graphdiyne/ graphene is investigated by ab initio calculations. The results show that for each amino acid molecule, the adsorption energy on graphdiyne is larger than the adsorption energy on graphene and dispersion interactions predominate in the adsorption. Molecular dynamics simulations reveal that at room temperature the amino acid molecules keep migrating and rotating on graphdiyne surface and induce fluctuation in graphdiyne bandgap. Additionally, the photon absorption spectra of graphdiyne-amino-acid systems are investigated. We uncover that the presence of amino acid molecules makes the photon absorption peaks of graphdiyne significantly depressed and shifted. Finally, quantum electronic transport properties of graphdiyne-amino-acid systems are compared with the transport properties of pure graphdiyne. We reveal that the amino acid molecules induce distinct changes in the electronic conductivity of graphdiyne. The results in this paper reveal that graphdiyne is a promising two-dimensional material for sensitively detecting amino acids and may potentially be used in biosensors. PMID:26568200

  2. Graphdiyne as a promising material for detecting amino acids.

    PubMed

    Chen, Xi; Gao, Pengfei; Guo, Lei; Zhang, Shengli

    2015-01-01

    The adsorption of glycine, glutamic acid, histidine and phenylalanine on single-layer graphdiyne/graphene is investigated by ab initio calculations. The results show that for each amino acid molecule, the adsorption energy on graphdiyne is larger than the adsorption energy on graphene and dispersion interactions predominate in the adsorption. Molecular dynamics simulations reveal that at room temperature the amino acid molecules keep migrating and rotating on graphdiyne surface and induce fluctuation in graphdiyne bandgap. Additionally, the photon absorption spectra of graphdiyne-amino-acid systems are investigated. We uncover that the presence of amino acid molecules makes the photon absorption peaks of graphdiyne significantly depressed and shifted. Finally, quantum electronic transport properties of graphdiyne-amino-acid systems are compared with the transport properties of pure graphdiyne. We reveal that the amino acid molecules induce distinct changes in the electronic conductivity of graphdiyne. The results in this paper reveal that graphdiyne is a promising two-dimensional material for sensitively detecting amino acids and may potentially be used in biosensors. PMID:26568200

  3. Detecting frame shifts by amino acid sequence comparison.

    PubMed

    Claverie, J M

    1993-12-20

    Various amino acid substitution scoring matrices are used in conjunction with local alignments programs to detect regions of similarity and infer potential common ancestry between proteins. The usual scoring schemes derive from the implicit hypothesis that related proteins evolve from a common ancestor by the accumulation of point mutations and that amino acids tend to be progressively substituted by others with similar properties. However, other frequent single mutation events, like nucleotide insertion or deletion and gene inversion, change the translation reading frame and cause previously encoded amino acid sequences to become unrecognizable at once. Here, I derive five new types of scoring matrix, each capable of detecting a specific frame shift (deletion, insertion and inversion in 3 frames) and use them with a regular local alignments program to detect amino acid sequences that may have derived from alternative reading frames of the same nucleotide sequence. Frame shifts are inferred from the sole comparison of the protein sequences. The five scoring matrices were used with the BLASTP program to compare all the protein sequences in the Swissprot database. Surprisingly, the searches revealed hundreds of highly significant frame shift matches, of which many are likely to represent sequencing errors. Others provide some evidence that frame shift mutations might be used in protein evolution as a way to create new amino acid sequences from pre-existing coding regions. PMID:7903399

  4. Method for detecting sophisticated cyber attacks

    SciTech Connect

    Potok, Thomas E.

    2008-11-18

    A method of analyzing computer intrusion detection information that looks beyond known attacks and abnormal access patterns to the critical information that an intruder may want to access. Unique target identifiers and type of work performed by the networked targets is added to audit log records. Analysis using vector space modeling, dissimilarity matrix comparison, and clustering of the event records is then performed.

  5. Method for detecting gas turbine engine flashback

    DOEpatents

    Singh, Kapil Kumar; Varatharajan, Balachandar; Kraemer, Gilbert Otto; Yilmaz, Ertan; Lacy, Benjamin Paul

    2012-09-04

    A method for monitoring and controlling a gas turbine, comprises predicting frequencies of combustion dynamics in a combustor using operating conditions of a gas turbine, receiving a signal from a sensor that is indicative of combustion dynamics in the combustor, and detecting a flashback if a frequency of the received signal does not correspond to the predicted frequencies.

  6. Method and apparatus for detecting an analyte

    DOEpatents

    Allendorf, Mark D.; Hesketh, Peter J.

    2011-11-29

    We describe the use of coordination polymers (CP) as coatings on microcantilevers for the detection of chemical analytes. CP exhibit changes in unit cell parameters upon adsorption of analytes, which will induce a stress in a static microcantilever upon which a CP layer is deposited. We also describe fabrication methods for depositing CP layers on surfaces.

  7. Improved astigmatic focus error detection method

    NASA Technical Reports Server (NTRS)

    Bernacki, Bruce E.

    1992-01-01

    All easy-to-implement focus- and track-error detection methods presently used in magneto-optical (MO) disk drives using pre-grooved media suffer from a side effect known as feedthrough. Feedthrough is the unwanted focus error signal (FES) produced when the optical head is seeking a new track, and light refracted from the pre-grooved disk produces an erroneous FES. Some focus and track-error detection methods are more resistant to feedthrough, but tend to be complicated and/or difficult to keep in alignment as a result of environmental insults. The astigmatic focus/push-pull tracking method is an elegant, easy-to-align focus- and track-error detection method. Unfortunately, it is also highly susceptible to feedthrough when astigmatism is present, with the worst effects caused by astigmatism oriented such that the tangential and sagittal foci are at 45 deg to the track direction. This disclosure outlines a method to nearly completely eliminate the worst-case form of feedthrough due to astigmatism oriented 45 deg to the track direction. Feedthrough due to other primary aberrations is not improved, but performance is identical to the unimproved astigmatic method.

  8. The determination of ascorbic acid and uric acid in human seminal plasma using an HPLC with UV detection.

    PubMed

    Kanďár, Roman; Drábková, Petra; Hampl, Radek

    2011-09-15

    Oxidative stress has been proposed as one of the potential causes for infertility in men. Ascorbic acid and uric acid play important role in protection of spermatozoa against free radicals. A method for the simultaneous determination of ascorbic acid and uric acid in human seminal plasma using HPLC with UV detection and investigation their clinical significance as antioxidants protecting male germ cells against oxidative damage are described. Semen samples were obtained from consecutive male partners of couples presenting for a fertility evaluation. After liquefaction, the samples were centrifuged and the supernatants were diluted with dithiothreitol solution and after a filtration injected onto an analytical column. For the separation, a reverse-phase column MAG 1, 250 mm × 4.6 mm, Labiospher PSI 100 C18, 5 μm, was used. The mixture of ethanol and 25 mmol/L sodium dihydrogenphosphate (2.5:97.5, v/v), pH 4.70 was used as a mobile phase. Analytical performance of this method is satisfactory for both ascorbic acid and uric acid: the intra-assay and inter-assay coefficients of variation were below 10%. Quantitative recoveries from spiked seminal plasma were between 92.1 and 102.1%. We have found no significant differences in both ascorbic acid and uric acid concentration between the smokers and non-smokers (351.0 ± 237.9 μmol/L and 323.7 ± 99.5 μmol/L vs. 444.8 ± 245.5 μmol/L and 316.6 ± 108.9 μmol/L, p>0.05). This assay is a simple and reproducible HPLC method for the simultaneous measurement of ascorbic acid and uric acid in human seminal plasma. PMID:21871848

  9. Kit for detecting nucleic acid sequences using competitive hybridization probes

    DOEpatents

    Lucas, Joe N.; Straume, Tore; Bogen, Kenneth T.

    2001-01-01

    A kit is provided for detecting a target nucleic acid sequence in a sample, the kit comprising: a first hybridization probe which includes a nucleic acid sequence that is sufficiently complementary to selectively hybridize to a first portion of the target sequence, the first hybridization probe including a first complexing agent for forming a binding pair with a second complexing agent; and a second hybridization probe which includes a nucleic acid sequence that is sufficiently complementary to selectively hybridize to a second portion of the target sequence to which the first hybridization probe does not selectively hybridize, the second hybridization probe including a detectable marker; a third hybridization probe which includes a nucleic acid sequence that is sufficiently complementary to selectively hybridize to a first portion of the target sequence, the third hybridization probe including the same detectable marker as the second hybridization probe; and a fourth hybridization probe which includes a nucleic acid sequence that is sufficiently complementary to selectively hybridize to a second portion of the target sequence to which the third hybridization probe does not selectively hybridize, the fourth hybridization probe including the first complexing agent for forming a binding pair with the second complexing agent; wherein the first and second hybridization probes are capable of simultaneously hybridizing to the target sequence and the third and fourth hybridization probes are capable of simultaneously hybridizing to the target sequence, the detectable marker is not present on the first or fourth hybridization probes and the first, second, third, and fourth hybridization probes each include a competitive nucleic acid sequence which is sufficiently complementary to a third portion of the target sequence that the competitive sequences of the first, second, third, and fourth hybridization probes compete with each other to hybridize to the third portion of the

  10. Method of increasing conversion of a fatty acid to its corresponding dicarboxylic acid

    DOEpatents

    Craft, David L.; Wilson, C. Ron; Eirich, Dudley; Zhang, Yeyan

    2004-09-14

    A nucleic acid sequence including a CYP promoter operably linked to nucleic acid encoding a heterologous protein is provided to increase transcription of the nucleic acid. Expression vectors and host cells containing the nucleic acid sequence are also provided. The methods and compositions described herein are especially useful in the production of polycarboxylic acids by yeast cells.

  11. Fault detection with principal component pursuit method

    NASA Astrophysics Data System (ADS)

    Pan, Yijun; Yang, Chunjie; Sun, Youxian; An, Ruqiao; Wang, Lin

    2015-11-01

    Data-driven approaches are widely applied for fault detection in industrial process. Recently, a new method for fault detection called principal component pursuit(PCP) is introduced. PCP is not only robust to outliers, but also can accomplish the objectives of model building, fault detection, fault isolation and process reconstruction simultaneously. PCP divides the data matrix into two parts: a fault-free low rank matrix and a sparse matrix with sensor noise and process fault. The statistics presented in this paper fully utilize the information in data matrix. Since the low rank matrix in PCP is similar to principal components matrix in PCA, a T2 statistic is proposed for fault detection in low rank matrix. And this statistic can illustrate that PCP is more sensitive to small variations in variables than PCA. In addition, in sparse matrix, a new monitored statistic performing the online fault detection with PCP-based method is introduced. This statistic uses the mean and the correlation coefficient of variables. Monte Carlo simulation and Tennessee Eastman (TE) benchmark process are provided to illustrate the effectiveness of monitored statistics.

  12. Analytical method for determination of benzene-arsenic acids

    SciTech Connect

    Mitchell, G.L.; Bayse, G.S.

    1988-01-01

    A sensitive analytical method has been modified for use in determination of several benzenearsonic acids, including arsanilic acid (p-aminobenzenearsonic acid), Roxarsone (3-nitro-4-hydroxybenzenearsonic acid), and p-ureidobenzene arsonic acid. Controlled acid hydrolysis of these compounds produces a quantitative yield of arsenate, which is measured colorimetrically as the molybdenum blue complex at 865 nm. The method obeys Beer's Law over the micromolar concentration range. These benzenearsonic acids are routinely used as feed additives in poultry and swine. This method should be useful in assessing tissue levels of the arsenicals in appropriate extracts.

  13. Ultrasensitive nucleic acid sequence detection by single-molecule electrophoresis

    SciTech Connect

    Castro, A; Shera, E.B.

    1996-09-01

    This is the final report of a one-year laboratory-directed research and development project at Los Alamos National Laboratory. There has been considerable interest in the development of very sensitive clinical diagnostic techniques over the last few years. Many pathogenic agents are often present in extremely small concentrations in clinical samples, especially at the initial stages of infection, making their detection very difficult. This project sought to develop a new technique for the detection and accurate quantification of specific bacterial and viral nucleic acid sequences in clinical samples. The scheme involved the use of novel hybridization probes for the detection of nucleic acids combined with our recently developed technique of single-molecule electrophoresis. This project is directly relevant to the DOE`s Defense Programs strategic directions in the area of biological warfare counter-proliferation.

  14. Method for nucleic acid hybridization using single-stranded DNA binding protein

    DOEpatents

    Tabor, Stanley; Richardson, Charles C.

    1996-01-01

    Method of nucleic acid hybridization for detecting the presence of a specific nucleic acid sequence in a population of different nucleic acid sequences using a nucleic acid probe. The nucleic acid probe hybridizes with the specific nucleic acid sequence but not with other nucleic acid sequences in the population. The method includes contacting a sample (potentially including the nucleic acid sequence) with the nucleic acid probe under hybridizing conditions in the presence of a single-stranded DNA binding protein provided in an amount which stimulates renaturation of a dilute solution (i.e., one in which the t.sub.1/2 of renaturation is longer than 3 weeks) of single-stranded DNA greater than 500 fold (i.e., to a t.sub.1/2 less than 60 min, preferably less than 5 min, and most preferably about 1 min.) in the absence of nucleotide triphosphates.

  15. Intrusion detection using pattern recognition methods

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Yu, Li

    2007-09-01

    Today, cyber attacks such as worms, scanning, active attackers are pervasive in Internet. A number of security approaches are proposed to address this problem, among which the intrusion detection system (IDS) appears to be one of the major and most effective solutions for defending against malicious users. Essentially, intrusion detection problem can be generalized as a classification problem, whose goal is to distinguish normal behaviors and anomalies. There are many well-known pattern recognition algorithms for classification purpose. In this paper we describe the details of applying pattern recognition methods to the intrusion detection research field. Experimenting on the KDDCUP 99 data set, we first use information gain metric to reduce the dimensionality of the original feature space. Two supervised methods, the support vector machine as well as the multi-layer neural network have been tested and the results display high detection rate and low false alarm rate, which is promising for real world applications. In addition, three unsupervised methods, Single-Linkage, K-Means, and CLIQUE, are also implemented and evaluated in the paper. The low computational complexity reveals their application in initial data reduction process.

  16. Detection methods for centrifugal microfluidic platforms.

    PubMed

    Burger, Robert; Amato, Letizia; Boisen, Anja

    2016-02-15

    Centrifugal microfluidics has attracted much interest from academia as well as industry, since it potentially offers solutions for affordable, user-friendly and portable biosensing. A wide range of so-called fluidic unit operations, e.g. mixing, metering, liquid routing, and particle separation, have been developed and allow automation and integration of complex assay protocols in lab-on-a-disc systems. Besides liquid handling, the detection strategy for reading out the assay is crucial for developing a fully integrated system. In this review, we focus on biosensors and readout methods for the centrifugal microfluidics platform and cover optical as well as mechanical and electrical detection principles. PMID:26166363

  17. Method and system for detecting an explosive

    DOEpatents

    Reber, Edward L.; Rohde, Kenneth W.; Blackwood, Larry G.

    2010-12-07

    A method and system for detecting at least one explosive in a vehicle using a neutron generator and a plurality of NaI detectors. Spectra read from the detectors is calibrated by performing Gaussian peak fitting to define peak regions, locating a Na peak and an annihilation peak doublet, assigning a predetermined energy level to one peak in the doublet, and predicting a hydrogen peak location based on a location of at least one peak of the doublet. The spectra are gain shifted to a common calibration, summed for respective groups of NaI detectors, and nitrogen detection analysis performed on the summed spectra for each group.

  18. Design of acid-lead battery stage-of-charge detection system based on refractive index detection technology

    NASA Astrophysics Data System (ADS)

    Chen, Junyao; Yang, Kecheng; Xia, Min; Li, Lei; Zeng, Xianjiang

    2015-10-01

    Based on optical total reflection critical Angle method, we have designed a refractive index measurement system. It adopted a divergent light source and a CCD camera as the occurrence and receiver of the signal. The divergent light source sent out a bunch of tapered beam, exposure to the interface of optical medium and sulfuric acid solution. Light intensity reflected from the interface could be detected by the CCD camera and then sent to the embedded system. In the DSP embedded system, we could obtain the critical edge position through the light intensity distribution curve and converted it to critical angle. Through experiment, we concluded the relation between liquid refractive index and the critical angle edge position. In this system, the detecting precision of the refractive index of sulfuric acid solution reached 10-4. Finally, through the conversion of the refractive index and density, we achieved high accuracy online measurement of electrolyte density in lead-acid battery.

  19. Electrophoretic Mobility Shift Assay (EMSA) for Detecting Protein-Nucleic Acid Interactions

    PubMed Central

    Hellman, Lance M.; Fried, Michael G.

    2009-01-01

    The gel electrophoresis mobility shift assay (EMSA) is used to detect protein complexes with nucleic acids. It is the core technology underlying a wide range of qualitative and quantitative analyses for the characterization of interacting systems. In the classical assay, solutions of protein and nucleic acid are combined and the resulting mixtures are subjected to electrophoresis under native conditions through polyacrylamide or agarose gel. After electrophoresis, the distribution of species containing nucleic acid is determined, usually by autoradiography of 32P-labeled nucleic acid. In general, protein-nucleic acid complexes migrate more slowly than the corresponding free nucleic acid. In this article, we identify the most important factors that determine the stabilities and electrophoretic mobilities of complexes under assay conditions. A representative protocol is provided and commonly used variants are discussed. Expected outcomes are briefly described. References to extensions of the method and a troubleshooting guide are provided. PMID:17703195

  20. A novel method for the diagnosis of drowning by detection of Aeromonas sobria with PCR method.

    PubMed

    Aoyagi, Miwako; Iwadate, Kimiharu; Fukui, Kenji; Abe, Shuntaro; Sakai, Kentaro; Maebashi, Kyoko; Ochiai, Eriko; Nakamura, Mihoko

    2009-11-01

    The acid digestion method has been widely used for the diagnosis of death by drowning, but it is not always sensitive. However, there has been no definitive method to replace acid digestion until now. We speculate that bacteria are more useful markers than plankton for the diagnosis of death by drowning. In this study, from the preserved blood samples of 32 freshwater drowning cases, specific DNA fragments of Aeromonas sobria, one of the most common aquatic bacteria, were examined using PCR. The DNA fragments of the bacterium were detected from 27 of 32 cases with first round PCR or nested-PCR. The remaining 5 cases in which bacterial DNA was not detected had longer storage periods for the blood samples and shorter time intervals from drowning to death. These results indicate that the present method can be applied to the diagnosis of death by drowning. PMID:19766051

  1. Need for new caries detection methods

    NASA Astrophysics Data System (ADS)

    Young, Douglas A.; Featherstone, John D. B.

    1999-05-01

    Dental caries (tooth decay) continues to be a major problems for adults as well as children, even though great advances have been made in preventive methods in the last 20 years. New methods for the management of caries will work best if lesions can be detected at an early stage and chemical rather than physical intervention can take place, thereby preserving the natural tooth structure and helping the saliva to heal, or remineralize, the areas of early decay. Clinical detection of caries in the US relies on visual examination, tactile with hand held explorer, and conventional radiographs, all of which are inadequate for the occlusal (biting) surfaces of the teeth where most of the decay now occurs. The dentist often has to explore by drilling with a dental bur to confirm early decay in these areas. New method that can determine the extent and degree of subsurface lesions in these surfaces non-destructively are essential for further advances in the clinical management of dental caries. Optical methods, which exploit the differences between sound and carious enamel and dentin, show great promise for the accurate detection of these lesions. Two or three- dimensional images, which include a measure of severity will be needed.

  2. Research and Design of Rootkit Detection Method

    NASA Astrophysics Data System (ADS)

    Liu, Leian; Yin, Zuanxing; Shen, Yuli; Lin, Haitao; Wang, Hongjiang

    Rootkit is one of the most important issues of network communication systems, which is related to the security and privacy of Internet users. Because of the existence of the back door of the operating system, a hacker can use rootkit to attack and invade other people's computers and thus he can capture passwords and message traffic to and from these computers easily. With the development of the rootkit technology, its applications are more and more extensive and it becomes increasingly difficult to detect it. In addition, for various reasons such as trade secrets, being difficult to be developed, and so on, the rootkit detection technology information and effective tools are still relatively scarce. In this paper, based on the in-depth analysis of the rootkit detection technology, a new kind of the rootkit detection structure is designed and a new method (software), X-Anti, is proposed. Test results show that software designed based on structure proposed is much more efficient than any other rootkit detection software.

  3. Lifting wavelet method of target detection

    NASA Astrophysics Data System (ADS)

    Han, Jun; Zhang, Chi; Jiang, Xu; Wang, Fang; Zhang, Jin

    2009-11-01

    Image target recognition plays a very important role in the areas of scientific exploration, aeronautics and space-to-ground observation, photography and topographic mapping. Complex environment of the image noise, fuzzy, all kinds of interference has always been to affect the stability of recognition algorithm. In this paper, the existence of target detection in real-time, accuracy problems, as well as anti-interference ability, using lifting wavelet image target detection methods. First of all, the use of histogram equalization, the goal difference method to obtain the region, on the basis of adaptive threshold and mathematical morphology operations to deal with the elimination of the background error. Secondly, the use of multi-channel wavelet filter wavelet transform of the original image de-noising and enhancement, to overcome the general algorithm of the noise caused by the sensitive issue of reducing the rate of miscarriage of justice will be the multi-resolution characteristics of wavelet and promotion of the framework can be designed directly in the benefits of space-time region used in target detection, feature extraction of targets. The experimental results show that the design of lifting wavelet has solved the movement of the target due to the complexity of the context of the difficulties caused by testing, which can effectively suppress noise, and improve the efficiency and speed of detection.

  4. Optimization of Quantitative PCR Methods for Enteropathogen Detection

    PubMed Central

    Liu, Jie; Gratz, Jean; Amour, Caroline; Nshama, Rosemary; Walongo, Thomas; Maro, Athanasia; Mduma, Esto; Platts-Mills, James; Boisen, Nadia; Nataro, James; Haverstick, Doris M.; Kabir, Furqan; Lertsethtakarn, Paphavee; Silapong, Sasikorn; Jeamwattanalert, Pimmada; Bodhidatta, Ladaporn; Mason, Carl; Begum, Sharmin; Haque, Rashidul; Praharaj, Ira; Kang, Gagandeep; Houpt, Eric R.

    2016-01-01

    Detection and quantification of enteropathogens in stool specimens is useful for diagnosing the cause of diarrhea but is technically challenging. Here we evaluate several important determinants of quantification: specimen collection, nucleic acid extraction, and extraction and amplification efficiency. First, we evaluate the molecular detection and quantification of pathogens in rectal swabs versus stool, using paired flocked rectal swabs and whole stool collected from 129 children hospitalized with diarrhea in Tanzania. Swabs generally yielded a higher quantification cycle (Cq) (average 29.7, standard deviation 3.5 vs. 25.3 ± 2.9 from stool, P<0.001) but were still able to detect 80% of pathogens with a Cq < 30 in stool. Second, a simplified total nucleic acid (TNA) extraction procedure was compared to separate DNA and RNA extractions and showed 92% (318/344) sensitivity and 98% (951/968) specificity, with no difference in Cq value for the positive results (ΔCq(DNA+RNA-TNA) = -0.01 ± 1.17, P = 0.972, N = 318). Third, we devised a quantification scheme that adjusts pathogen quantity to the specimen’s extraction and amplification efficiency, and show that this better estimates the quantity of spiked specimens than the raw target Cq. In sum, these methods for enteropathogen quantification, stool sample collection, and nucleic acid extraction will be useful for laboratories studying enteric disease. PMID:27336160

  5. Visual detection of nucleic acids based on Mie scattering and the magnetophoretic effect.

    PubMed

    Zhao, Zichen; Chen, Shan; Ho, John Kin Lim; Chieng, Ching-Chang; Chen, Ting-Hsuan

    2015-12-01

    Visual detection of nucleic acid biomarkers is a simple and convenient approach to point-of-care applications. However, issues of sensitivity and the handling of complex bio-fluids have posed challenges. Here we report on a visual method detecting nucleic acids using Mie scattering of polystyrene microparticles and the magnetophoretic effect. Magnetic microparticles (MMPs) and polystyrene microparticles (PMPs) were surface-functionalised with oligonucleotide probes, which can hybridise with target oligonucleotides in juxtaposition and lead to the formation of MMPs-targets-PMPs sandwich structures. Using an externally applied magnetic field, the magnetophoretic effect attracts the sandwich structure to the sidewall, which reduces the suspended PMPs and leads to a change in the light transmission via the Mie scattering. Based on the high extinction coefficient of the Mie scattering (∼3 orders of magnitude greater than that of the commonly used gold nanoparticles), our results showed the limit of detection to be 4 pM using a UV-Vis spectrometer or 10 pM by direct visual inspection. Meanwhile, we also demonstrated that this method is compatible with multiplex assays and detection in complex bio-fluids, such as whole blood or a pool of nucleic acids, without purification in advance. With a simplified operation procedure, low instrumentation requirement, high sensitivity and compatibility with complex bio-fluids, this method provides an ideal solution for visual detection of nucleic acids in resource-limited settings. PMID:26332289

  6. DNA tetrahedron and star trigon nanostructures for target recycling detection of nucleic acid.

    PubMed

    Li, Yueran; Chen, Xifeng; Wang, Bidou; Liu, Guangxing; Tang, Yuguo; Miao, Peng

    2016-06-01

    Human immunodeficiency virus (HIV) is a retrovirus which attacks the human body's immune system and further leads to acquired immunodeficiency syndrome (AIDS). Nucleic acid detection is of great importance in the medical diagnosis of such diseases. Herein, we develop a simple and enzyme-free electrochemical method for the target recycling detection of nuclei acid. DNA tetrahedron and star trigon nanostructures are designed and constructed on the electrode interface for target capture and signal enrichment. This strategy is convenient and sensitive, with a limit of detection as low as 1 fM, and can also successfully distinguish single-base mismatched DNA. Therefore, the proposed method has a promising potential application for HIV DNA detection. PMID:27170090

  7. Detecting data anomalies methods in distributed systems

    NASA Astrophysics Data System (ADS)

    Mosiej, Lukasz

    2009-06-01

    Distributed systems became most popular systems in big companies. Nowadays many telecommunications companies want to hold large volumes of data about all customers. Obviously, those data cannot be stored in single database because of many technical difficulties, such as data access efficiency, security reasons, etc. On the other hand there is no need to hold all data in one place, because companies already have dedicated systems to perform specific tasks. In the distributed systems there is a redundancy of data and each system holds only interesting data in appropriate form. Data updated in one system should be also updated in the rest of systems, which hold that data. There are technical problems to update those data in all systems in transactional way. This article is about data anomalies in distributed systems. Avail data anomalies detection methods are shown. Furthermore, a new initial concept of new data anomalies detection methods is described on the last section.

  8. System and method for anomaly detection

    DOEpatents

    Scherrer, Chad

    2010-06-15

    A system and method for detecting one or more anomalies in a plurality of observations is provided. In one illustrative embodiment, the observations are real-time network observations collected from a stream of network traffic. The method includes performing a discrete decomposition of the observations, and introducing derived variables to increase storage and query efficiencies. A mathematical model, such as a conditional independence model, is then generated from the formatted data. The formatted data is also used to construct frequency tables which maintain an accurate count of specific variable occurrence as indicated by the model generation process. The formatted data is then applied to the mathematical model to generate scored data. The scored data is then analyzed to detect anomalies.

  9. Surface property detection apparatus and method

    DOEpatents

    Martens, Jon S.; Ginley, David S.; Hietala, Vincent M.; Sorensen, Neil R.

    1995-01-01

    Apparatus and method for detecting, determining, and imaging surface resistance corrosion, thin film growth, and oxide formation on the surface of conductors or other electrical surface modification. The invention comprises a modified confocal resonator structure with the sample remote from the radiating mirror. Surface resistance is determined by analyzing and imaging reflected microwaves; imaging reveals anomalies due to surface impurities, non-stoichiometry, and the like, in the surface of the superconductor, conductor, dielectric, or semiconductor.

  10. Surface property detection apparatus and method

    DOEpatents

    Martens, J.S.; Ginley, D.S.; Hietala, V.M.; Sorensen, N.R.

    1995-08-08

    Apparatus and method for detecting, determining, and imaging surface resistance corrosion, thin film growth, and oxide formation on the surface of conductors or other electrical surface modification. The invention comprises a modified confocal resonator structure with the sample remote from the radiating mirror. Surface resistance is determined by analyzing and imaging reflected microwaves; imaging reveals anomalies due to surface impurities, non-stoichiometry, and the like, in the surface of the superconductor, conductor, dielectric, or semiconductor. 4 figs.

  11. Corona solar blind ultraviolet image detecting method

    NASA Astrophysics Data System (ADS)

    Yin, Li-min; Tang, Wen-qing; Zhang, Yu

    2009-07-01

    Corona is one of important reasons of electrical energy loss in the electric power. According to incomplete statistics, corona loss electrical energy has achieved two thousands and fifty millions kW.h in our nation every year. Sometimes corona also can have some disturbance to radio and communication. Therefore to discover and examine corona promptly has the extremely vital significance for conserving energy and realizing high quality communication. Ultraviolet image detecting technology is a preferred corona detection method in electric power. It may realize all-weather reliable survey to corona. The solar blind ultraviolet signal discharged by corona is quite weak. Moreover the ultraviolet image quality has been affected seriously by the detection system noise. A corona solar blind ultraviolet image processing method is proposed in this paper. Ultraviolet image has so small target, low contrast image, district characteristic and real-time demand that it is processed by multi-scale ultraviolet morphology filter technology based on mathematics morphology in this paper. Results show that the method can stretch image contrast, enhance target and weaken noise. The algorithm is easy to deal in parallel and it can be realized easily by hardware. It will be accurately demarcated when the condition of device need to be absolutely measured. The paper proposes a kind of mathematics morphology algorithm. Solar blind ultraviolet image will be further processed according to temperature and humidity in order to remove the infection of corona discharge demarcation and solve correct demarcation question when equipment condition need to be absolutely measured.

  12. Improved method for detection of starch hydrolysis

    SciTech Connect

    Ohawale, M.R.; Wilson, J.J.; Khachatourians, G.G.; Ingledew, W.M.

    1982-09-01

    A new starch hydrolysis detection method which does not rely on iodine staining or the use of color-complexed starch is described. A linear relationship was obtained with agar-starch plates when net clearing zones around colonies of yeasts were plotted against enzyme levels (semilogarithm scale) produced by the same yeast strains in liquid medium. A similar relationship between starch clearing zones and alpha-amylase levels from three different sources was observed. These observations suggest that the method is useful in mutant isolations, strain improvement programs, and the prediction of alpha-amylase activities in culture filtrates or column effluents. (Refs. 18).

  13. Detection Method of TOXOPLASMA GONDII Tachyzoites

    NASA Astrophysics Data System (ADS)

    Eassa, Souzan; Bose, Chhanda; Alusta, Pierre; Tarasenko, Olga

    2011-06-01

    Tachyzoites are considered to be the most important stage of Toxoplasma gondii which causes toxoplasmosis. T. gondii is, an obligate intracellular parasite which infects a wide range of cells. The present study was designed to develop a method for an early detection of T. gondii tachyzoites. The method comprised of a binding assay which was analyzed using principal component and cluster analysis. Our data showed that glycoconjugates GC1, GC2, GC3 and GC10 exhibit a significantly higher binding affinity for T. gondii tachyzoites as compared to controls (T. gondii only, PAA only, GC 1, 2, 3, and 10 only).

  14. A new IQ detection method for LLRF

    NASA Astrophysics Data System (ADS)

    Qiu, Feng; Gao, Jie; Lin, Hai-ying; Liu, Rong; Ma, Xin-peng; Sha, Peng; Sun, Yi; Wang, Guang-wei; Wang, Qun-yao; Xu, Bo; Zeng, Ri-hua

    2012-05-01

    Digital LLRF technology has been widely used in new generation particle accelerators. IF quadrature sampling is a common method for amplitude and phase detection. Many strategies, which obey the same rule of fsample=(M/N)fIF (M/N is a rational number), have been proposed to reduce the effects of spectrum aliasing. However, we found that M/N does not need to be a rational number according to Shannon's theorem. Therefore, we propose a new IQ detection method in this paper. This method is based on a special IIR filter which is derived from an RLC circuit. The unique characteristic of the method is that the value of fIF is independent of the value of fsample. We have set up an experimental platform to verify our method. A 122.88 MHz sampling clock is used to sample a 3 MHz IF signal. The DDS and PI control techniques are used to realize the closed-loop control. Results show that the stability of the system is within ± 0.05% (peak to peak) for the amplitude, and with ±0.03° (peak to peak) for the phase in 5 h.

  15. Detection of Acetic Acid in wine by means of an electronic nose

    NASA Astrophysics Data System (ADS)

    Lozano, Jesús; Álvarez, Fernando; Santos, José Pedro; Horrillo, Carmen

    2011-09-01

    A portable electronic nose (see Fig.1) based on metal oxide semiconductor thin-film sensors has been developed to detect acetic acid present in four types of wines. The wines analyzed are from the same cellar but are made with different varieties of grapes. Data analysis was performed by two pattern recognition methods: principal component analysis (PCA) and Artificial Neural Networks (ANN).

  16. Mid-ultraviolet light-emitting diode detects dipicolinic acid.

    SciTech Connect

    Bogart, Katherine Huderle Andersen; Lee, Stephen Roger; Temkin, Henryk; Crawford, Mary Hagerott; Dasgupta, Purnendu K.; Li, Qingyang; Allerman, Andrew Alan; Fischer, Arthur Joseph

    2005-06-01

    Dipicolinic acid (DPA, 2,6-pyridinedicarboxylic acid) is a substance uniquely present in bacterial spores such as that from anthrax (B. anthracis). It is known that DPA can be detected by the long-lived fluorescence of its terbium chelate; the best limit of detection (LOD) reported thus far using a large benchtop gated fluorescence instrument using a pulsed Xe lamp is 2 nM. We use a novel AlGaN light-emitting diode (LED) fabricated on a sapphire substrate that has peak emission at 291 nm. Although the overlap of the emission band of this LED with the absorption band of Tb-DPA ({lambda}{sub max} doublet: 273, 279 nm) is not ideal, we demonstrate that a compact detector based on this LED and an off-the-shelf gated photodetection module can provide an LOD of 0.4 nM, thus providing a basis for convenient early warning detectors.

  17. Waterborne Pathogens: Detection Methods and Challenges

    PubMed Central

    Ramírez-Castillo, Flor Yazmín; Loera-Muro, Abraham; Jacques, Mario; Garneau, Philippe; Avelar-González, Francisco Javier; Harel, Josée; Guerrero-Barrera, Alma Lilián

    2015-01-01

    Waterborne pathogens and related diseases are a major public health concern worldwide, not only by the morbidity and mortality that they cause, but by the high cost that represents their prevention and treatment. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally. Proper assessment of pathogens on water and water quality monitoring are key factors for decision-making regarding water distribution systems’ infrastructure, the choice of best water treatment and prevention waterborne outbreaks. Powerful, sensitive and reproducible diagnostic tools are developed to monitor pathogen contamination in water and be able to detect not only cultivable pathogens but also to detect the occurrence of viable but non-culturable microorganisms as well as the presence of pathogens on biofilms. Quantitative microbial risk assessment (QMRA) is a helpful tool to evaluate the scenarios for pathogen contamination that involve surveillance, detection methods, analysis and decision-making. This review aims to present a research outlook on waterborne outbreaks that have occurred in recent years. This review also focuses in the main molecular techniques for detection of waterborne pathogens and the use of QMRA approach to protect public health. PMID:26011827

  18. Waterborne pathogens: detection methods and challenges.

    PubMed

    Ramírez-Castillo, Flor Yazmín; Loera-Muro, Abraham; Jacques, Mario; Garneau, Philippe; Avelar-González, Francisco Javier; Harel, Josée; Guerrero-Barrera, Alma Lilián

    2015-01-01

    Waterborne pathogens and related diseases are a major public health concern worldwide, not only by the morbidity and mortality that they cause, but by the high cost that represents their prevention and treatment. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally. Proper assessment of pathogens on water and water quality monitoring are key factors for decision-making regarding water distribution systems' infrastructure, the choice of best water treatment and prevention waterborne outbreaks. Powerful, sensitive and reproducible diagnostic tools are developed to monitor pathogen contamination in water and be able to detect not only cultivable pathogens but also to detect the occurrence of viable but non-culturable microorganisms as well as the presence of pathogens on biofilms. Quantitative microbial risk assessment (QMRA) is a helpful tool to evaluate the scenarios for pathogen contamination that involve surveillance, detection methods, analysis and decision-making. This review aims to present a research outlook on waterborne outbreaks that have occurred in recent years. This review also focuses in the main molecular techniques for detection of waterborne pathogens and the use of QMRA approach to protect public health. PMID:26011827

  19. Current methods for detecting ethylene in plants

    PubMed Central

    Cristescu, Simona M.; Mandon, Julien; Arslanov, Denis; De Pessemier, Jérôme; Hermans, Christian; Harren, Frans J. M.

    2013-01-01

    Background In view of ethylene's critical developmental and physiological roles the gaseous hormone remains an active research topic for plant biologists. Progress has been made to understand the ethylene biosynthesis pathway and the mechanisms of perception and action. Still numerous questions need to be answered and findings to be validated. Monitoring gas production will very often complete the picture of any ethylene research topic. Therefore the search for suitable ethylene measuring methods for various plant samples either in the field, greenhouses, laboratories or storage facilities is strongly motivated. Scope This review presents an update of the current methods for ethylene monitoring in plants. It focuses on the three most-used methods – gas chromatography detection, electrochemical sensing and optical detection – and compares them in terms of sensitivity, selectivity, time response and price. Guidelines are provided for proper selection and application of the described sensor methodologies and some specific applications are illustrated of laser-based detector for monitoring ethylene given off by Arabidopsis thaliana upon various nutritional treatments. Conclusions Each method has its advantages and limitations. The choice for the suitable ethylene sensor needs careful consideration and is driven by the requirements for a specific application. PMID:23243188

  20. Label-free functional nucleic acid sensors for detecting target agents

    DOEpatents

    Lu, Yi; Xiang, Yu

    2015-01-13

    A general methodology to design label-free fluorescent functional nucleic acid sensors using a vacant site approach and an abasic site approach is described. In one example, a method for designing label-free fluorescent functional nucleic acid sensors (e.g., those that include a DNAzyme, aptamer or aptazyme) that have a tunable dynamic range through the introduction of an abasic site (e.g., dSpacer) or a vacant site into the functional nucleic acids. Also provided is a general method for designing label-free fluorescent aptamer sensors based on the regulation of malachite green (MG) fluorescence. A general method for designing label-free fluorescent catalytic and molecular beacons (CAMBs) is also provided. The methods demonstrated here can be used to design many other label-free fluorescent sensors to detect a wide range of analytes. Sensors and methods of using the disclosed sensors are also provided.

  1. NAIL: Nucleic Acid detection using Isotachophoresis and Loop-mediated isothermal amplification.

    PubMed

    Borysiak, Mark D; Kimura, Kevin W; Posner, Jonathan D

    2015-04-01

    Nucleic acid amplification tests are the gold standard for many infectious disease diagnoses due to high sensitivity and specificity, rapid operation, and low limits of detection. Despite the advantages of nucleic acid amplification tests, they currently offer limited point-of-care (POC) utility due to the need for complex instruments and laborious sample preparation. We report the development of the Nucleic Acid Isotachophoresis LAMP (NAIL) diagnostic device. NAIL uses isotachophoresis (ITP) and loop-mediated isothermal amplification (LAMP) to extract and amplify nucleic acids from complex matrices in less than one hour inside of an integrated chip. ITP is an electrokinetic separation technique that uses an electric field and two buffers to extract and purify nucleic acids in a single step. LAMP amplifies nucleic acids at constant temperature and produces large amounts of DNA that can be easily detected. A mobile phone images the amplification results to eliminate the need for laser fluorescent detection. The device requires minimal user intervention because capillary valves and heated air chambers act as passive valves and pumps for automated fluid actuation. In this paper, we describe NAIL device design and operation, and demonstrate the extraction and detection of pathogenic E. coli O157:H7 cells from whole milk samples. We use the Clinical and Laboratory Standards Institute (CLSI) limit of detection (LoD) definitions that take into account the variance from both positive and negative samples to determine the diagnostic LoD. According to the CLSI definition, the NAIL device has a limit of detection (LoD) of 1000 CFU mL(-1) for E. coli cells artificially inoculated into whole milk, which is two orders of magnitude improvement to standard tube-LAMP reactions with diluted milk samples and comparable to lab-based methods. The NAIL device potentially offers significant reductions in the complexity and cost of traditional nucleic acid diagnostics for POC applications

  2. [Detection of cyclopiazonic acid and its producers in food].

    PubMed

    Ostrý, V; Polster, M

    1989-07-01

    In the course of six months, 60 samples of foods were examined for their contents of cyclopiazonic acid. These samples were subjected to a basal mycological screening aimed at Aspergillus flavus and Penicillium sp. strains. Cyclopiazonic acid contents in samples of Hermelín cheese, peanuts, rice, peeled barley grains, Folican salami, and packaged meat did not exceed the value of 0.5 mg.kg-1. When using a modification of the method of cyclopiazonic acid isolation described by Dorner et al. (1983), 521 mg of this mycotoxin were isolated from a culture of Penicillium griseofulvum CCM 8006 strain grown in liquid medium containing 2% yeast autolysate and 2.5% sucrose. About 47% of the isolated Aspergillus flavus strains were bitoxicogenic (produced both cyclopiazonic acid and aflatoxin). Cyclopiazonic acid was produced by 23.5% of the isolated Penicillium sp. strains. No cyclopiazonic acid was produced in vitro by Penicillium nalgoviensis strains from the Czechoslovak collection on sweet wort agar containing peptone from soybean. Penicillium commune F-426 and Penicillium aurantiogriseum F-708 strains are efficient producers of this acid. PMID:2508296

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

    PubMed Central

    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

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

    PubMed

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

    2014-01-01

    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

  5. Development of a bacterial bioassay for atrazine and cyanuric acid detection

    PubMed Central

    Hua, Anna; Gueuné, Hervé; Cregut, Mickaël; Thouand, Gérald; Durand, Marie-José

    2015-01-01

    The s-triazine herbicides are compounds which can disseminate into soils and water. Due to their toxic effects on living organisms, their concentrations in drinking water are legislated by WHO recommendations. Here we have developed for the first time, to the best of our knowledge, an alternative method for physicochemical quantification using two bioluminescent bacterial biosensors: E. coli SM003 for cyanuric acid detection and E. coli SM004 for both atrazine and cyanuric acid detection. The concentration of cyanuric acid detection for E. coli SM003 ranges from 7.83 μM to 2.89 mM, and for E. coli SM004 ranges from 0.22 to 15 μM. Moreover, atrazine detection by E. coli SM004 ranges from 1.08 to 15 μM. According to WHO recommendations, the cyanuric acid detection range is sensitive enough to discriminate between polluted and drinking water. Nevertheless, the detection of atrazine by E. coli SM004 is only applicable for high concentrations of contaminants. PMID:25852669

  6. Halocarbon refrigerant detection methods. Final report

    SciTech Connect

    Tapscott, R.E.; Sohn, C.W.

    1996-01-01

    The Montreal Protocol and the U.S. Clean Air Act limit the production of ozone-depleting substances, including many refrigerants. Three options for cost-effectively phasing out these refrigerants from Army installations are: (1) refrigerant containment, (2) retrofit conversion to accommodate alternative refrigerant, and (3) replacement with cooling systems using alternative refrigerant. This report contributes to the first option by identifying and assessing methods to detect chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants that leak from air-conditioning and refrigeration systems. As background, the report describes the relevant sections of the Montreal Protocol and the Clean Air Act, and gives an overview of refrigerants. This is followed by a description of the technologies used in refrigerant leak detection, and a survey of detector types available and their price ranges. Appendixes provide an extensive list of detector products and their specifications, plus manufacturer addresses and phone numbers.

  7. ULTRASONIC FLAW DETECTION METHOD AND MEANS

    DOEpatents

    Worlton, D.C.

    1961-08-15

    A method of detecting subsurface flaws in an object using ultrasonic waves is described. An ultnasonic wave of predetermined velocity and frequency is transmitted to engage the surface of the object at a predetermined angle of inci dence thereto. The incident angle of the wave to the surface is determined with respect to phase velocity, incident wave velocity, incident wave frequency, and the estimated depth of the flaw so that Lamb waves of a particular type and mode are induced only in the portion of the object between the flaw and the surface. These Lamb waves are then detected as they leave the object at an angle of exit equal to the angle of incidence. No waves wlll be generated in the object and hence received if no flaw exists beneath the surface. (AEC)

  8. Bayesian Methods for Radiation Detection and Dosimetry

    SciTech Connect

    Peter G. Groer

    2002-09-29

    We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a method to obtain Bayesian estimates of 222Rn-daughter products from observed counting rates. In external radiation dosimetry we studied and developed Bayesian methods to estimate radiation doses to an individual with radiation induced chromosome aberrations. We analyzed chromosome aberrations after exposure to gammas and neutrons and developed a method for dose-estimation after criticality accidents. The research in internal radiation dosimetry focused on parameter estimation for compartmental models from observed compartmental activities. From the estimated probability densities of the model parameters we were able to derive the densities for compartmental activities for a two compartment catenary model at different times. We also calculated the average activities and their standard deviation for a simple two compartment model.

  9. Method and apparatus for detecting neutrons

    DOEpatents

    Perkins, Richard W.; Reeder, Paul L.; Wogman, Ned A.; Warner, Ray A.; Brite, Daniel W.; Richey, Wayne C.; Goldman, Don S.

    1997-01-01

    The instant invention is a method for making and using an apparatus for detecting neutrons. Scintillating optical fibers are fabricated by melting SiO.sub.2 with a thermal neutron capturing substance and a scintillating material in a reducing atmosphere. The melt is then drawn into fibers in an anoxic atmosphere. The fibers may then be coated and used directly in a neutron detection apparatus, or assembled into a geometrical array in a second, hydrogen-rich, scintillating material such as a polymer. Photons generated by interaction with thermal neutrons are trapped within the coated fibers and are directed to photoelectric converters. A measurable electronic signal is generated for each thermal neutron interaction within the fiber. These electronic signals are then manipulated, stored, and interpreted by normal methods to infer the quality and quantity of incident radiation. When the fibers are arranged in an array within a second scintillating material, photons generated by kinetic neutrons interacting with the second scintillating material and photons generated by thermal neutron capture within the fiber can both be directed to photoelectric converters. These electronic signals are then manipulated, stored, and interpreted by normal methods to infer the quality and quantity of incident radiation.

  10. Method and apparatus for detecting neutrons

    DOEpatents

    Perkins, R.W.; Reeder, P.L.; Wogman, N.A.; Warner, R.A.; Brite, D.W.; Richey, W.C.; Goldman, D.S.

    1997-10-21

    The instant invention is a method for making and using an apparatus for detecting neutrons. Scintillating optical fibers are fabricated by melting SiO{sub 2} with a thermal neutron capturing substance and a scintillating material in a reducing atmosphere. The melt is then drawn into fibers in an anoxic atmosphere. The fibers may then be coated and used directly in a neutron detection apparatus, or assembled into a geometrical array in a second, hydrogen-rich, scintillating material such as a polymer. Photons generated by interaction with thermal neutrons are trapped within the coated fibers and are directed to photoelectric converters. A measurable electronic signal is generated for each thermal neutron interaction within the fiber. These electronic signals are then manipulated, stored, and interpreted by normal methods to infer the quality and quantity of incident radiation. When the fibers are arranged in an array within a second scintillating material, photons generated by kinetic neutrons interacting with the second scintillating material and photons generated by thermal neutron capture within the fiber can both be directed to photoelectric converters. These electronic signals are then manipulated, stored, and interpreted by normal methods to infer the quality and quantity of incident radiation. 5 figs.

  11. Luminescent Probes for Ultrasensitive Detection of Nucleic Acids

    PubMed Central

    Krasnoperov, Lev N.; Marras, Salvatore A.E.; Kozlov, Maxim; Wirpsza, Laura; Mustaev, Arkady

    2010-01-01

    Novel amino-reactive derivatives of lanthanide-based luminescent labels of enhanced brightness and metal retention were synthesized and used for the detection of complementary DNA oligonucleotides by molecular beacons. Time-resolved acquisition of the luminescent signal that occurs upon hybridization of the probe to the target enabled the avoidance of short-lived background fluorescence, markedly enhancing the sensitivity of detection, which was less than 1 pM. This value is about 50 to 100 times more sensitive than the level achieved with conventional fluorescence-based molecular beacons, and is 10 to 60 times more sensitive than previously reported for other lanthanide-based hybridization probes. These novel luminescent labels should significantly enhance the sensitivity of all type of nucleic acid hybridization probes, and could dramatically improve the detection limit of other biopolymers and small compounds that are used in a variety of biological applications. PMID:20085336

  12. Method and apparatus for detecting explosives

    DOEpatents

    Moore, David Steven

    2011-05-10

    A method and apparatus is provided for detecting explosives by thermal imaging. The explosive material is subjected to a high energy wave which can be either a sound wave or an electromagnetic wave which will initiate a chemical reaction in the explosive material which chemical reaction will produce heat. The heat is then sensed by a thermal imaging device which will provide a signal to a computing device which will alert a user of the apparatus to the possibility of an explosive device being present.

  13. Systems and methods for detecting and processing

    DOEpatents

    Johnson, Michael M.; Yoshimura, Ann S.

    2006-03-28

    Embodiments of the present invention provides systems and method for detecting. Sensing modules are provided in communication with one or more detectors. In some embodiments, detectors are provided that are sensitive to chemical, biological, or radiological agents. Embodiments of sensing modules include processing capabilities to analyze, perform computations on, and/or run models to predict or interpret data received from one or more detectors. Embodiments of sensing modules form various network configurations with one another and/or with one or more data aggregation devices. Some embodiments of sensing modules include power management functionalities.

  14. Total Acid Value Titration of Hydrotreated Biomass Fast Pyrolysis Oil: Determination of Carboxylic Acids and Phenolics with Multiple End-Point Detection

    SciTech Connect

    Christensen, E.; Alleman, T. L.; McCormick, R. L.

    2013-01-01

    Total acid value titration has long been used to estimate corrosive potential of petroleum crude oil and fuel oil products. The method commonly used for this measurement, ASTM D664, utilizes KOH in isopropanol as the titrant with potentiometric end point determination by pH sensing electrode and Ag/AgCl reference electrode with LiCl electrolyte. A natural application of the D664 method is titration of pyrolysis-derived bio-oil, which is a candidate for refinery upgrading to produce drop in fuels. Determining the total acid value of pyrolysis derived bio-oil has proven challenging and not necessarily amenable to the methodology employed for petroleum products due to the different nature of acids present. We presented an acid value titration for bio-oil products in our previous publication which also utilizes potentiometry using tetrabutylammonium hydroxide in place of KOH as the titrant and tetraethylammonium bromide in place of LiCl as the reference electrolyte to improve the detection of these types of acids. This method was shown to detect numerous end points in samples of bio-oil that were not detected by D664. These end points were attributed to carboxylic acids and phenolics based on the results of HPLC and GC-MS studies. Additional work has led to refinement of the method and it has been established that both carboxylic acids and phenolics can be determined accurately. Use of pH buffer calibration to determine half-neutralization potentials of acids in conjunction with the analysis of model compounds has allowed us to conclude that this titration method is suitable for the determination of total acid value of pyrolysis oil and can be used to differentiate and quantify weak acid species. The measurement of phenolics in bio-oil is subject to a relatively high limit of detection, which may limit the utility of titrimetric methodology for characterizing the acidic potential of pyrolysis oil and products.

  15. Traumatic Brain Injury Detection Using Electrophysiological Methods

    PubMed Central

    Rapp, Paul E.; Keyser, David O.; Albano, Alfonso; Hernandez, Rene; Gibson, Douglas B.; Zambon, Robert A.; Hairston, W. David; Hughes, John D.; Krystal, Andrew; Nichols, Andrew S.

    2015-01-01

    Measuring neuronal activity with electrophysiological methods may be useful in detecting neurological dysfunctions, such as mild traumatic brain injury (mTBI). This approach may be particularly valuable for rapid detection in at-risk populations including military service members and athletes. Electrophysiological methods, such as quantitative electroencephalography (qEEG) and recording event-related potentials (ERPs) may be promising; however, the field is nascent and significant controversy exists on the efficacy and accuracy of the approaches as diagnostic tools. For example, the specific measures derived from an electroencephalogram (EEG) that are most suitable as markers of dysfunction have not been clearly established. A study was conducted to summarize and evaluate the statistical rigor of evidence on the overall utility of qEEG as an mTBI detection tool. The analysis evaluated qEEG measures/parameters that may be most suitable as fieldable diagnostic tools, identified other types of EEG measures and analysis methods of promise, recommended specific measures and analysis methods for further development as mTBI detection tools, identified research gaps in the field, and recommended future research and development thrust areas. The qEEG study group formed the following conclusions: (1) Individual qEEG measures provide limited diagnostic utility for mTBI. However, many measures can be important features of qEEG discriminant functions, which do show significant promise as mTBI detection tools. (2) ERPs offer utility in mTBI detection. In fact, evidence indicates that ERPs can identify abnormalities in cases where EEGs alone are non-disclosing. (3) The standard mathematical procedures used in the characterization of mTBI EEGs should be expanded to incorporate newer methods of analysis including non-linear dynamical analysis, complexity measures, analysis of causal interactions, graph theory, and information dynamics. (4) Reports of high specificity in q

  16. Improved agar diffusion method for detecting residual antimicrobial agents.

    PubMed

    Tsai, C E; Kondo, F

    2001-03-01

    The improved agar diffusion method for determination of residual antimicrobial agents was investigated, and the sensitivities of various combinations of test organisms and assay media were determined using 7 organisms, 5 media, and 31 antimicrobial agents. Bacillus stearothermophilus and synthetic assay medium (SAM) showed the greatest sensitivity for screening penicillins (penicillin G and ampicillin). The combination of Bacillus subtilis and minimum medium (MM) was the most sensitive for tetracyclines (oxytetracycline and chlortetracycline), B. stearothermophilus and SAM or Micrococcus luteus and Mueller-Hinton agar (MHA) for detecting tylosin and erythromycin, B. subtilis and MHA for aminoglycosides (streptomycin, kanamycin, gentamicin, and dihydrostreptomycin), B. stearothermophilus and SAM for polyethers (salinomycin and lasalocid), and B. subtilis and MM or Clostridium perfringens and GAM for polypeptides (thiopeptin, enramycin, virginiamycin, and bacitracin). However, gram-negative bacterium Escherichia coli ATCC 27166 and MM were better for screening for colistin and polymixin-B. For detecting the synthetic drugs tested, the best combination was B. subtilis and MM for sulfonamides, E. coli 27166 and MM for quinolones (oxolinic acid and nalidixic acid), B. subtilis and MM for furans (furazolidone), and the bioluminescent bacterium Photobacterium phosphoreum and luminescence assay medium for chloramphenicol and oxolinic acid. The results showed that the use of four assay plates, B. stearothermophilus and SAM, B. subtilis and MM, M. luteus and MHA, and E. coli 27166 and MM, was superior to the currently available techniques for screening for residual antimicrobial agents in edible animal tissues. PMID:11252480

  17. Methods and Instruments for Fast Neutron Detection

    SciTech Connect

    Jordan, David V.; Reeder, Paul L.; Cooper, Matthew W.; McCormick, Kathleen R.; Peurrung, Anthony J.; Warren, Glen A.

    2005-05-01

    Pacific Northwest National Laboratory evaluated the performance of a large-area (~0.7 m2) plastic scintillator time-of-flight (TOF) sensor for direct detection of fast neutrons. This type of sensor is a readily area-scalable technology that provides broad-area geometrical coverage at a reasonably low cost. It can yield intrinsic detection efficiencies that compare favorably with moderator-based detection methods. The timing resolution achievable should permit substantially more precise time windowing of return neutron flux than would otherwise be possible with moderated detectors. The energy-deposition threshold imposed on each scintillator contributing to the event-definition trigger in a TOF system can be set to blind the sensor to direct emission from the neutron generator. The primary technical challenge addressed in the project was to understand the capabilities of a neutron TOF sensor in the limit of large scintillator area and small scintillator separation, a size regime in which the neutral particle’s flight path between the two scintillators is not tightly constrained.

  18. Radiation sensitive area detection device and method

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C. (Inventor); Hecht, Diana L. (Inventor); Witherow, William K. (Inventor)

    1991-01-01

    A radiation sensitive area detection device for use in conjunction with an X ray, ultraviolet or other radiation source is provided which comprises a phosphor containing film which releases a stored diffraction pattern image in response to incoming light or other electromagnetic wave. A light source such as a helium-neon laser, an optical fiber capable of directing light from the laser source onto the phosphor film and also capable of channelling the fluoresced light from the phosphor film to an integrating sphere which directs the light to a signal processing means including a light receiving means such as a photomultiplier tube. The signal processing means allows translation of the fluoresced light in order to detect the original pattern caused by the diffraction of the radiation by the original sample. The optical fiber is retained directly in front of the phosphor screen by a thin metal holder which moves up and down across the phosphor screen and which features a replaceable pinhole which allows easy adjustment of the resolution of the light projected onto the phosphor film. The device produces near real time images with high spatial resolution and without the distortion that accompanies prior art devices employing photomultiplier tubes. A method is also provided for carrying out radiation area detection using the device of the invention.

  19. Collection and analysis of organic acids in exhaust gas. Comparison of different methods

    NASA Astrophysics Data System (ADS)

    Zervas, E.; Montagne, X.; Lahaye, J.

    This paper reports the development of a specific method to identify organic acids in exhaust gases. The organic acids are collected in two impingers containing liquids (pure water or Na 2CO 3 1% aqueous solution) and four cartridges containing solids (silica, fluorisil, alumina B and alumina N). Once collected, the acids are eluted of the solids by a hot water stream. These traps performances, in terms of organic acids collection and elution efficiency, are evaluated and compared. Two sources are used to produce the gas flow containing organic acids: one generates a flow whose concentration is known and stable, the other produces organic acids among other combustion products. For eluted solutions analysis, two methods are used: isocratic ionic chromatography/conductivity detection and GC/FID. Their efficiency in separating 10 aliphatic acids are compared. Their characteristics such as detection limits, detection linearity, repeatability and possible interferences with other components found in exhaust gases are determined. The stability of the organic acids solutions is also studied. Lastly, the use of these methods is illustrated by the analysis of the gas-phase organic acids exhausted by a spark ignition and by a diesel engine.

  20. Synthesis of positively charged CdTe quantum dots and detection for uric acid

    NASA Astrophysics Data System (ADS)

    Zhang, Tiliang; Sun, Xiangying; Liu, Bin

    2011-09-01

    The CdTe dots (QDs) coated with 2-Mercaptoethylamine was prepared in aqueous solution and characterized with fluorescence spectroscopy, UV-Vis absorption spectra, high-resolution transmission electron microscopy and infrared spectroscopy. When the λex = 350 nm, the fluorescence peak of positively charged CdTe quantum dots is at 592 nm. The uric acid is able to quench their fluorescence. Under optimum conditions, the change of fluorescence intensity is linearly proportional to the concentration of uric acid in the range 0.4000-3.600 μmol L -1, and the limit of detection calculated according to IUPAC definitions is 0.1030 μmol L -1. Compared with routine method, the present method determines uric acid in human serum with satisfactory results. The mechanism of this strategy is due to the interaction of the tautomeric keto/hydroxyl group of uric acid and the amino group coated at the CdTe QDs.

  1. Lagrangian based methods for coherent structure detection

    SciTech Connect

    Allshouse, Michael R.; Peacock, Thomas

    2015-09-15

    There has been a proliferation in the development of Lagrangian analytical methods for detecting coherent structures in fluid flow transport, yielding a variety of qualitatively different approaches. We present a review of four approaches and demonstrate the utility of these methods via their application to the same sample analytic model, the canonical double-gyre flow, highlighting the pros and cons of each approach. Two of the methods, the geometric and probabilistic approaches, are well established and require velocity field data over the time interval of interest to identify particularly important material lines and surfaces, and influential regions, respectively. The other two approaches, implementing tools from cluster and braid theory, seek coherent structures based on limited trajectory data, attempting to partition the flow transport into distinct regions. All four of these approaches share the common trait that they are objective methods, meaning that their results do not depend on the frame of reference used. For each method, we also present a number of example applications ranging from blood flow and chemical reactions to ocean and atmospheric flows.

  2. Lagrangian based methods for coherent structure detection.

    PubMed

    Allshouse, Michael R; Peacock, Thomas

    2015-09-01

    There has been a proliferation in the development of Lagrangian analytical methods for detecting coherent structures in fluid flow transport, yielding a variety of qualitatively different approaches. We present a review of four approaches and demonstrate the utility of these methods via their application to the same sample analytic model, the canonical double-gyre flow, highlighting the pros and cons of each approach. Two of the methods, the geometric and probabilistic approaches, are well established and require velocity field data over the time interval of interest to identify particularly important material lines and surfaces, and influential regions, respectively. The other two approaches, implementing tools from cluster and braid theory, seek coherent structures based on limited trajectory data, attempting to partition the flow transport into distinct regions. All four of these approaches share the common trait that they are objective methods, meaning that their results do not depend on the frame of reference used. For each method, we also present a number of example applications ranging from blood flow and chemical reactions to ocean and atmospheric flows. PMID:26428570

  3. Platelet antibody: review of detection methods

    SciTech Connect

    Schwartz, K.A.

    1988-10-01

    The driving force behind development of in vitro methods for platelet antibodies is identification of plasma factors causing platelet destruction. Early methods relied on measurement of platelet activation. Current methods are more specific and use a purified antibody against immunoglobulin or complement, which is usually labeled with /sup 125/I or tagged with an enzyme or fluorescein. Comparisons of quantitation of platelet-associated IgG show wide variability between different methods. The disparate results can be related both to differences in binding of secondary antibodies to immunoglobulin in solution compared to immunoglobulins attached to platelets and to the improper assumption that the binding ratio between the secondary detecting and primary antiplatelet antibody is one. Most assays can 1) identify neonatal isoimmune thrombocytopenia and posttransfusion purpura, 2) help to differentiate between immune and nonimmune thrombocytopenias, 3) help to sort out the offending drug when drug-induced thrombocytopenia is suspected, and 4) identify platelet alloantibodies and potential platelet donors via a cross match assay for refractory patients. However, the advantages of quantitative assays over qualitative methods with respect to predictions of patients clinical course and response to different treatments remain to be investigated. 61 references.

  4. Advanced negative detection method comparable to silver stain for SDS-PAGE separated proteins detection.

    PubMed

    Wang, Xu; Hwang, Sun-Young; Cong, Wei-Tao; Jin, Li-Tai; Choi, Jung-Kap

    2016-10-01

    In order to achieve an easy, rapid and sensitive protocol to detect proteins in polyacrylamide gel, an advanced negative detection method comparable to silver stain is described. When a gel was incubated with Phloxine B and followed by the development in acidic solution, the zones where forming protein-dye complex were selectively transparent, unlike opaque gel background. Within 50 min after electrophoresis, down to 0.1-0.4 ng of gel-separated proteins (similar with silver stain) could be observed, without labor-intensive and time-consuming procedure. Comparing with the most common negative stain method, Imidazole-zinc stain, Phloxine B stain has been shown higher sensitivity and distinct contrast between the transparent protein bands/spots and opaque background than those; furthermore, it is no longer necessary to concern about retention time of observation. This technique may provide a sensitive and practical choice for proteomics researches. PMID:27430933

  5. Acetic Acid Detection Threshold in Synthetic Wine Samples of a Portable Electronic Nose

    PubMed Central

    Macías, Miguel Macías; Manso, Antonio García; Orellana, Carlos Javier García; Velasco, Horacio Manuel González; Caballero, Ramón Gallardo; Chamizo, Juan Carlos Peguero

    2013-01-01

    Wine quality is related to its intrinsic visual, taste, or aroma characteristics and is reflected in the price paid for that wine. One of the most important wine faults is the excessive concentration of acetic acid which can cause a wine to take on vinegar aromas and reduce its varietal character. Thereby it is very important for the wine industry to have methods, like electronic noses, for real-time monitoring the excessive concentration of acetic acid in wines. However, aroma characterization of alcoholic beverages with sensor array electronic noses is a difficult challenge due to the masking effect of ethanol. In this work, in order to detect the presence of acetic acid in synthetic wine samples (aqueous ethanol solution at 10% v/v) we use a detection unit which consists of a commercial electronic nose and a HSS32 auto sampler, in combination with a neural network classifier (MLP). To find the characteristic vector representative of the sample that we want to classify, first we select the sensors, and the section of the sensors response curves, where the probability of detecting the presence of acetic acid will be higher, and then we apply Principal Component Analysis (PCA) such that each sensor response curve is represented by the coefficients of its first principal components. Results show that the PEN3 electronic nose is able to detect and discriminate wine samples doped with acetic acid in concentrations equal or greater than 2 g/L. PMID:23262483

  6. Absorbance detection of amino acids by laser wave mixing in microbore liquid chromatography.

    PubMed

    Wu, Z; Tong, W G

    1998-05-01

    Nonlinear optical phase conjugation by degenerate four-wave mixing is demonstrated as a sensitive "absorbance" detection method for microbore high-performance liquid chromatography. An argon ion laser operating at the 488-nm line is used as the excitation light source to generate the wave-mixing signal for dabsyl-labeled amino acids. Advantages of the nonlinear laser detection method include: virtually 100% optical signal collection efficiency, generation of the signal in the form of a coherent laser beam, signal measurement against a virtually dark background, reliable detection of small absorbance values, excellent detection sensitivity for both fluorescing and non-fluorescing analytes, relatively simple one-color one-laser optical setup, and low power or energy requirements for continuous-wave or pulsed lasers. Using our one-laser one-color nonlinear laser detector for "absorbance" measurements in liquid chromatography, we report a crude preliminary "injected" detection limit of 780 fmol for glycine. PMID:9618915

  7. Method and system for detecting explosives

    DOEpatents

    Reber, Edward L.; Jewell, James K.; Rohde, Kenneth W.; Seabury, Edward H.; Blackwood, Larry G.; Edwards, Andrew J.; Derr, Kurt W.

    2009-03-10

    A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

  8. Method and apparatus for vapor detection

    NASA Technical Reports Server (NTRS)

    Lerner, Melvin (Inventor); Hood, Lyal V. (Inventor); Rommel, Marjorie A. (Inventor); Pettitt, Bruce C. (Inventor); Erikson, Charles M. (Inventor)

    1980-01-01

    The method disclosed herein may be practiced by passing the vapors to be sampled along a path with halogen vapor, preferably chlorine vapor, heating the mixed vapors to halogenate those of the sampled vapors subject to halogenation, removing unreacted halogen vapor, and then sensing the vapors for organic halogenated compounds. The apparatus disclosed herein comprises means for flowing the vapors, both sample and halogen vapors, into a common path, means for heating the mixed vapors to effect the halogenation reaction, means for removing unreacted halogen vapor, and a sensing device for sensing halogenated compounds. By such a method and means, the vapors of low molecular weight hydrocarbons, ketones and alcohols, when present, such as methane, ethane, acetone, ethanol, and the like are converted, at least in part, to halogenated compounds, then the excess halogen removed or trapped, and the resultant vapors of the halogenated compounds sensed or detected. The system is highly sensitive. For example, acetone in a concentration of 30 parts per billion (volume) is readily detected.

  9. New method to detect caries via fluorescence

    NASA Astrophysics Data System (ADS)

    Eberhart, J.; Frentzen, M.; Thoms, M.

    2007-07-01

    Caries, a common and widespread infectious disease, has to be detected as early as possible. Based on the need for an easy and handy tool for preventing invasive treatment a new fluorescence camera system has been developed. Using this camera the so-called porphyrins, metabolic products of oral pathogenic bacteria can be visualized. Thereby fluorophores are excited at a wavelength of 405nm by the built-in GaN-LEDs. Healthy and diseased dental hard tissues fluoresce in the green and in the red spectral range, respectively, thus allowing differentiation by coulor. To prove the reliability of this fluorescence camera system, freshly extracted teeth were examined. Three different methods of analysis were verified and compared to give information about the lesions (sensitivity & selectivity): The extent of the fluorescence area, the integral of the red/green ratio of the lesion and the maximum red/green ratio in the area of interest. Histological sections of the teeth served as reference. In addition, the camera was compared to a tip probe sensor already available on the market. In total, our results show that regarding the three different algorithms of analysis, the maximum of the red/green ratio is a preferential method to evaluate carious lesions. Sound tissue, enamel caries and dentin caries can be clearly distinguished. The new fluorescence camera is a handy, efficient and fast device in order to detect lesions and seems to be superior to the tip probe sensor regarding the positioning. Further studies are required.

  10. A paper based microfluidic device for easy detection of uric acid using positively charged gold nanoparticles.

    PubMed

    Kumar, Anand; Hens, Abhiram; Arun, Ravi Kumar; Chatterjee, Monosree; Mahato, Kuldeep; Layek, Keya; Chanda, Nripen

    2015-03-21

    A paper based microfluidic device is fabricated that can rapidly detect very low concentrations of uric acid (UA) using 3,5,3',5'-tetramethyl benzidine (TMB), H2O2 and positively charged gold nanoparticles ((+)AuNPs). In the presence of (+)AuNPs, H2O2 reacts with TMB to produce a bluish-green colour which becomes colourless on reaction with UA. This colorimetric method can detect as low as 8.1 ppm of UA within <20 minutes on white filter paper. This technique provides an alternative way for UA detection. PMID:25655365

  11. [Determination of organic acids in cane vinasse by micellar electrokinetic capillary chromatography with indirect ultraviolet detection].

    PubMed

    Xu, Yuanjin; Xu, Guiping; Wei, Yuanan

    2006-01-01

    Micellar electrokinetic capillary chromatography (MECC) with indirect ultraviolet (UV) detection method for the separation and determination of several organic acids in cane vinasse, including malonic, formic, tartaric, malic, succinic, glutaric, acetic, lactic and glutamic acids, were developed. Electrophoretic conditions were as follows: uncoated fused silica capillary (56 cm/ 64 cm (effective/total length), 50 microm i. d. ), 7.5 mmol/L potassium acid phthalate-1. 5 mmol/L cetyltrimethyl-ammonium bromide (CTAB) at pH = 6.50 as buffer solution, applied voltage -25 kV, temperature 25 degrees C, detection wavelength 300 nm, reference wavelength 210 nm. Good linearities were obtained for nine organic acids, and the detection limits were 0.5 mg/L, 0.3 mg/L, 1.5 mg/L, 1.5 mg/L, 0.3 mg/L, 0.3 mg/L, 0.4 mg/L, 0.4 mg/L, 0.4 mg/L for malonic, formic, tartaric, malic, succinic, glutaric, acetic, lactic and glutamic acid, respectively. The relative standard deviations (RSDs) for migration times and peak areas of nine organic acids within a day were 0.4% - 0.6% and 2.3% - 4.8%, respectively. The corresponding data for five days were 0.5% -0.7% and 3.3% - 5.2%. The recoveries of acid standards were above 93%. The method can be applied to determine the organic acids in cane vinasse with satisfactory results. PMID:16827307

  12. Amplified electrochemical detection of nucleic acid hybridization via selective preconcentration of unmodified gold nanoparticles.

    PubMed

    Li, Yuan; Tian, Rui; Zheng, Xingwang; Huang, Rongfu

    2016-08-31

    The common drawback of optical methods for rapid detection of nucleic acid by exploiting the differential affinity of single-/double-stranded nucleic acids for unmodified gold nanoparticles (AuNPs) is its relatively low sensitivity. In this article, on the basis of selective preconcentration of AuNPs unprotected by single-stranded DNA (ssDNA) binding, a novel electrochemical strategy for nucleic acid sequence identification assay has been developed. Through detecting the redox signal mediated by AuNPs on 1, 6-hexanedithiol blocked gold electrode, the proposed method is able to ensure substantial signal amplification and a low background current. This strategy is demonstrated for quantitative analysis of the target microRNA (let-7a) in human breast adenocarcinoma cells, and a detection limit of 16 fM is readily achieved with desirable specificity and sensitivity. These results indicate that the selective preconcentration of AuNPs for electrochemical signal readout can offer a promising platform for the detection of specific nucleic acid sequence. PMID:27506344

  13. Detection of saccharides by reactive desorption electrospray ionization (DESI) using modified phenylboronic acids

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Chen, Hao

    2010-01-01

    We have reported previously a method for the detection of sugars via in-situ derivatization with phenylboronic acid PhB(OH)2 using reactive desorption electrospray ionization (DESI, Chen et al., Chem. Commun. (2006) 597-599). The present study describes an improved method that employs modified phenylboronic acids including 3-nitrophenylboronic acid and N-methyl-4-pyridineboronic acid iodide. In contrast to using PhB(OH)2, enhanced sensitivity of using 3-nitrophenylboronic acid was observed due to the stabilization of the resulting boronate ester anion by the electron-withdrawing nitro group and the limit of detections (LODs) for glucose in water using 3-nitrophenylbornic acid and phenylboronic acid were determined to be 0.11 mM and 0.40 mM, respectively. In the case of N-methyl-4-pyridineboronic acid iodide, the corresponding LOD is 6.9 [mu]M and the higher sensitivity obtained is attributed to the efficient ionization of both the reactive DESI reagent and reaction product since the precursor acid with a quaternary ammonium group is pre-charged. In this case, additional important features are found: (i) unlike using phenylboronic acid or 3-nitrophenylbornic acid, the experiment, performed in the positive ion mode, is applicable to neutral and acidic saccharide solutions, facilitating the analysis of biological fluids without the need to adjust pH; (ii) simply by changing the spray solvent from water to acetonitrile, the method can be used for direct glucose analyses of both urine and serum samples via online desalting, due to the low solubility of salts of these biofluids in the sprayed organic solvent; (iii) in comparison with other sugar derivatizing reagents such as the Girard's reagent T, the N-methyl-4-pyridineboronic acid iodide shows higher reactivity in the reactive DESI; and (iv) the ions of saccharide DESI reaction products undergo extensive ring or glycosidic bond cleavage upon CID, a feature that might be useful in the structure elucidation of

  14. A fluorometric assay platform for caffeic acid detection based on the G-quadruplex/hemin DNAzyme.

    PubMed

    Cai, Nan; Li, Yan; Chen, Shufan; Su, Xingguang

    2016-07-21

    In this paper, a fluorometric assay platform for fluorescence detection of caffeic acid was designed based on the peroxidase-mimicking activities of G-quadruplex/hemin DNAzyme. Under the catalysis of the formed G-quadruplex/hemin complex, H2O2 could be decomposed into hydroxyl radicals with strong oxidation properties. Then caffeic acid would be oxidized by the released hydroxyl radicals, resulting in the product caffeic acid-quinone. Normally, caffeic acid has no influence on the fluorescence of graphene quantum dots. But when mixed with the G-quadruplex/hemin complex and H2O2, the fluorescence of graphene quantum dots was obviously quenched by the oxidized caffeic acid. Under the optimized experimental conditions, the quenched fluorescence intensity was linearly correlated with the concentration of caffeic acid, ranging from 2 μM to 350 μM with a detection limit of 200 nM. The proposed method was applied to the determination of caffeic acid in human serum samples with satisfactory results. PMID:27220084

  15. Rapid Methods for High-Throughput Detection of Sulfoxides▿

    PubMed Central

    Shainsky, Janna; Derry, Netta-Lee; Leichtmann-Bardoogo, Yael; Wood, Thomas K.; Fishman, Ayelet

    2009-01-01

    Enantiopure sulfoxides are prevalent in drugs and are useful chiral auxiliaries in organic synthesis. The biocatalytic enantioselective oxidation of prochiral sulfides is a direct and economical approach for the synthesis of optically pure sulfoxides. The selection of suitable biocatalysts requires rapid and reliable high-throughput screening methods. Here we present four different methods for detecting sulfoxides produced via whole-cell biocatalysis, three of which were exploited for high-throughput screening. Fluorescence detection based on the acid activation of omeprazole was utilized for high-throughput screening of mutant libraries of toluene monooxygenases, but no active variants have been discovered yet. The second method is based on the reduction of sulfoxides to sulfides, with the coupled release and measurement of iodine. The availability of solvent-resistant microtiter plates enabled us to modify the method to a high-throughput format. The third method, selective inhibition of horse liver alcohol dehydrogenase, was used to rapidly screen highly active and/or enantioselective variants at position V106 of toluene ortho-monooxygenase in a saturation mutagenesis library, using methyl-p-tolyl sulfide as the substrate. A success rate of 89% (i.e., 11% false positives) was obtained, and two new mutants were selected. The fourth method is based on the colorimetric detection of adrenochrome, a back-titration procedure which measures the concentration of the periodate-sensitive sulfide. Due to low sensitivity during whole-cell screening, this method was found to be useful only for determining the presence or absence of sulfoxide in the reaction. The methods described in the present work are simple and inexpensive and do not require special equipment. PMID:19465532

  16. Efficient Computer Network Anomaly Detection by Changepoint Detection Methods

    NASA Astrophysics Data System (ADS)

    Tartakovsky, Alexander G.; Polunchenko, Aleksey S.; Sokolov, Grigory

    2013-02-01

    We consider the problem of efficient on-line anomaly detection in computer network traffic. The problem is approached statistically, as that of sequential (quickest) changepoint detection. A multi-cyclic setting of quickest change detection is a natural fit for this problem. We propose a novel score-based multi-cyclic detection algorithm. The algorithm is based on the so-called Shiryaev-Roberts procedure. This procedure is as easy to employ in practice and as computationally inexpensive as the popular Cumulative Sum chart and the Exponentially Weighted Moving Average scheme. The likelihood ratio based Shiryaev-Roberts procedure has appealing optimality properties, particularly it is exactly optimal in a multi-cyclic setting geared to detect a change occurring at a far time horizon. It is therefore expected that an intrusion detection algorithm based on the Shiryaev-Roberts procedure will perform better than other detection schemes. This is confirmed experimentally for real traces. We also discuss the possibility of complementing our anomaly detection algorithm with a spectral-signature intrusion detection system with false alarm filtering and true attack confirmation capability, so as to obtain a synergistic system.

  17. Studies on fatty acid-binding proteins. The detection and quantification of the protein from rat liver by using a fluorescent fatty acid analogue.

    PubMed Central

    Wilkinson, T C; Wilton, D C

    1986-01-01

    Fatty acid-binding protein from rat liver is shown to bind the fluorescent fatty acid probe dansyl undecanoic acid. Binding is accompanied by a shift in the fluorescence emission maximum from 550 nm to 500 nm and a 60-fold fluorescence enhancement at 500 nm. These spectral properties have allowed the use of this probe to detect and quantify microgram amounts of liver fatty acid-binding protein during purification procedures. In conjunction with h.p.l.c. the method allows the rapid estimation of liver fatty acid-binding protein in biological samples. The validity of the method is demonstrated by measuring the concentration of fatty acid-binding protein in livers from control and hypolipidaemic-drug-treated rats. The dramatic diurnal rhythm previously reported for this protein [Dempsey (1984) Curr. Top. Cell. Regul. 24, 63-86] was not observed with this method. Images Fig. 1. PMID:3800946

  18. Methods of staining target chromosomal DNA employing high complexity nucleic acid probes

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel; Kallioniemi, Ol'li-Pekka; Kallioniemi, Anne; Sakamoto, Masaru

    2006-10-03

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML), retinoblastoma, ovarian and uterine cancers, and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  19. Sensitive and selective electrochemical detection of artemisinin based on its reaction with p-aminophenylboronic acid.

    PubMed

    Wang, Chao; Zholudov, Yuriy T; Nsabimana, Anaclet; Xu, Guobao; Li, Jianping

    2016-09-21

    The electrochemical detection of artemisinin generally requires high oxidation potential or the use of complex electrode modification. We find that artemisinin can react with p-aminophenylboronic acid to produce easily electrochemically detectable aminophenol for the first time. By making use of the new reaction, we report an alternative method to detect artemisinin through the determination of p-aminophenol. The calibration curve for the determination of artemisinin is linear in the range of 2 μmol L(-1) to 200 μmol L(-1) with the detection limit of 0.8 μmol L(-1), which is more sensitive than other reported electrochemical methods. The relative standard deviation is 4.83% for the determination of 10 μM artemisinin. Because the oxidation potential of p-aminophenol is around 0 V, the present method is high selective. When 40 μM, 90 μM and 140 μM of artemisinin were spiked to compound naphthoquine phosphate tablet samples, the recoveries are 107.6%, 105.4% and 101.7%, respectively. This detection strategy is attractive for the detection of artemisinin and its derivatives. The finding that artemisinin can react with aromatic boronic acid has the potential to be exploited for the development of other sensors, such as fluorescence artemisinin sensors. PMID:27590543

  20. Odour Detection Methods: Olfactometry and Chemical Sensors

    PubMed Central

    Brattoli, Magda; de Gennaro, Gianluigi; de Pinto, Valentina; Loiotile, Annamaria Demarinis; Lovascio, Sara; Penza, Michele

    2011-01-01

    The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc.) and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality); this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants) as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses) are then described, focusing on their better performances for environmental analysis. Odour emission monitoring carried out

  1. Development of fluorescent nanoparticle-labeled lateral flow assay for the detection of nucleic acids.

    PubMed

    Wang, Yuhong; Nugen, Sam R

    2013-10-01

    The rapid, specific and sensitive detection of nucleic acids is of utmost importance for the identification of infectious agents, diagnosis and treatment of genetic diseases, and the detection of pathogens related to human health and safety. Here we report the development of a simple and sensitive nucleic acid sequence-based and Ru(bpy)3 (2+)-doped silica nanoparticle-labeled lateral flow assay which achieves low limit of detection by using fluorescencent nanoparticles. The detection of the synthetic nucleic acid sequences representative of Trypanosoma mRNA, the causative agent for African sleeping sickness, was utilized to demonstrate this assay. The 30 nm spherical Ru(bpy)3 (2+)-doped silica nanoparticles were prepared in aqueous medium by a novel method recently reported. The nanoparticles were modified by 3-glycidoxypropyl trimethoxysilane in order to conjugate to amine-capped oligonucleotide reporter probes. The fluorescent intensities of the fluorescent assays were quantified on a mictrotiter plate reader using a custom holder. The experimental results showed that the lateral flow fluorescent assay developed was more sensitive compared with the traditional colloidal gold test strips. The limit of detection for the fluorescent lateral flow assay developed is approximately 0.066 fmols as compared to approximately 15 fmols for the colloidal gold. The limit of detection can further be reduced about one order of magnitude when "dipstick" format was used. PMID:23525961

  2. Early Detection of Mycobacteria Using a Novel Hydrogel Culture Method

    PubMed Central

    Jang, Mi Hee; Kim, Shine Young; Kim, Chang-Ki; Hwang, Sang-Hyun; Park, Byung Kyu; Kim, Sung Soo; Lee, Eun Yup

    2014-01-01

    Background Early laboratory detection of Mycobacterium tuberculosis is crucial for controlling tuberculosis. We developed a hydrogel mycobacterial culture method that retains the advantages of both solid and liquid methods in terms of speed, cost, and efficiency. Methods Mycobacterium bovis bacillus Calmette-Guérin (BCG) suspensions and 200 acid-fast bacilli (AFB)-positive clinical specimens were inoculated in Middlebrook 7H9 liquid media (Becton-Dickinson and Company, USA) and mixed with 75 µL of 9-fluorenylmethoxycarbonyl (Fmoc)-Phe-Phe-OH hydrogel stock solution in an Eppendorf tube just before culture incubation. The mixtures were cultured at 37℃ for as long as 14 days to monitor culture status. Results The number of M. bovis BCG increased with time. For 200 AFB smear-positive specimens, 155 of 158 conventional culture-positive specimens and 4 culture-negative or contaminated specimens yielded positive cultures within 14 days. For 128 specimens positive with the liquid culture method, the time to positive culture using the hydrogel method (mean, 12.6 days; range, 7 to 14 days) was significantly shorter than that for conventional liquid culture (mean, 16.2 days; range, 6 to 31 days; P<0.0001). Conclusions The hydrogel scaffold culture system is useful for timely, economical, and efficient detection of mycobacteria in clinical specimens. PMID:24422192

  3. Hazard Detection Methods for Lunar Landing

    NASA Technical Reports Server (NTRS)

    Brady, Tye; Zimpfer, Doug; Robertson, Edward; Epp, Chirold; Paschall, Stephen

    2009-01-01

    The methods and experiences from the Apollo Program are fundamental building blocks for the development of lunar landing strategies for the Constellation Program. Each of the six lunar landing Apollo missions landed under near ideal lighting conditions. The astronauts visually performed terrain relative navigation while looking out of windows, and were greatly aided by external communication and well lit scenes. As the LM approached the landing site, the astronauts performed visual hazard detection and avoidance, also under near-ideal lighting conditions. The astronauts were looking out of the windows trying to the best of their ability to avoid rocks, slopes, and craters and find a safe landing location. NASA has expressed a desire for global lunar access for both crewed and robotic sortie lunar exploration missions (Cook, 2007) (Dale, 2006). Early NASA architecture studies have identified the lunar poles as desirable locations for early lunar missions. These polar missions have less than ideal lighting conditions and will significantly affect the way a crewed vehicle plans to land at such locales. Consequently, a variety of hazard identification methods should be considered for use by the crew to ensure a high degree of safety. This paper discusses such identification methods applicable to the poorly lit polar lunar environment, better ensuring global access for the soon to be designed Lunar Lander Vehicle (LLV).

  4. Method and system for turbomachinery surge detection

    DOEpatents

    Faymon, David K.; Mays, Darrell C.; Xiong, Yufei

    2004-11-23

    A method and system for surge detection within a gas turbine engine, comprises: measuring the compressor discharge pressure (CDP) of the gas turbine over a period of time; determining a time derivative (CDP.sub.D ) of the measured (CDP) correcting the CDP.sub.D for altitude, (CDP.sub.DCOR); estimating a short-term average of CDP.sub.DCOR.sup.2 ; estimating a short-term average of CDP.sub.DCOR ; and determining a short-term variance of corrected CDP rate of change (CDP.sub.roc) based upon the short-term average of CDP.sub.DCOR and the short-term average of CDP.sub.DCOR.sup.2. The method and system then compares the short-term variance of corrected CDP rate of change with a pre-determined threshold (CDP.sub.proc) and signals an output when CDP.sub.roc >CDP.sub.proc. The method and system provides a signal of a surge within the gas turbine engine when CDP.sub.roc remains>CDP.sub.proc for pre-determined period of time.

  5. Continuous-flow free acid monitoring method and system

    DOEpatents

    Strain, J.E.; Ross, H.H.

    1980-01-11

    A free acid monitoring method and apparatus is provided for continuously measuring the excess acid present in a process stream. The disclosed monitoring system and method is based on the relationship of the partial pressure ratio of water and acid in equilibrium with an acid solution at constant temperature. A portion of the process stream is pumped into and flows through the monitor under the influence of gravity and back to the process stream. A continuous flowing sample is vaporized at a constant temperature and the vapor is subsequently condensed. Conductivity measurements of the condensate produces a nonlinear response function from which the free acid molarity of the sample process stream is determined.

  6. Continuous-flow free acid monitoring method and system

    DOEpatents

    Strain, James E.; Ross, Harley H.

    1981-01-01

    A free acid monitoring method and apparatus is provided for continuously measuring the excess acid present in a process stream. The disclosed monitoring system and method is based on the relationship of the partial pressure ratio of water and acid in equilibrium with an acid solution at constant temperature. A portion of the process stream is pumped into and flows through the monitor under the influence of gravity and back to the process stream. A continuous flowing sample is vaporized at a constant temperature and the vapor is subsequently condensed. Conductivity measurements of the condensate produces a nonlinear response function from which the free acid molarity of the sample process stream is determined.

  7. Solar cell anomaly detection method and apparatus

    NASA Technical Reports Server (NTRS)

    Miller, Emmett L. (Inventor); Shumka, Alex (Inventor); Gauthier, Michael K. (Inventor)

    1981-01-01

    A method is provided for detecting cracks and other imperfections in a solar cell, which includes scanning a narrow light beam back and forth across the cell in a raster pattern, while monitoring the electrical output of the cell to find locations where the electrical output varies significantly. The electrical output can be monitored on a television type screen containing a raster pattern with each point on the screen corresponding to a point on the solar cell surface, and with the brightness of each point on the screen corresponding to the electrical output from the cell which was produced when the light beam was at the corresponding point on the cell. The technique can be utilized to scan a large array of interconnected solar cells, to determine which ones are defective.

  8. Liquid chromatography detection unit, system, and method

    SciTech Connect

    Derenzo, Stephen E.; Moses, William W.

    2015-10-27

    An embodiment of a liquid chromatography detection unit includes a fluid channel and a radiation detector. The radiation detector is operable to image a distribution of a radiolabeled compound as the distribution travels along the fluid channel. An embodiment of a liquid chromatography system includes an injector, a separation column, and a radiation detector. The injector is operable to inject a sample that includes a radiolabeled compound into a solvent stream. The position sensitive radiation detector is operable to image a distribution of the radiolabeled compound as the distribution travels along a fluid channel. An embodiment of a method of liquid chromatography includes injecting a sample that comprises radiolabeled compounds into a solvent. The radiolabeled compounds are then separated. A position sensitive radiation detector is employed to image distributions of the radiolabeled compounds as the radiolabeled compounds travel along a fluid channel.

  9. Systems and methods for detecting neutrons

    DOEpatents

    Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

    2005-08-09

    Systems and methods for detecting neutrons. One or more neutron-sensitive scintillators can be configured from a plurality of nano-sized particles, dopants and an extruded plastic material, such as polystyrene. The nano-sized particles can be compounded into the extruded plastic material with at least one dopant that permits the plastic material to scintillate. One or more plastic light collectors can be associated with a neutron-sensitive scintillator, such that the plastic light collector includes a central hole thereof. A wavelength-shifting fiber can then be located within the hole. The wavelength shifting (WLS) fiber absorbs scintillation light having a wavelength thereof and re-emits the light at a longer wavelength.

  10. Methods and kits for nucleic acid analysis using fluorescence resonance energy transfer

    DOEpatents

    Kwok, Pui-Yan; Chen, Xiangning

    1999-01-01

    A method for detecting the presence of a target nucleotide or sequence of nucleotides in a nucleic acid is disclosed. The method is comprised of forming an oligonucleotide labeled with two fluorophores on the nucleic acid target site. The doubly labeled oligonucleotide is formed by addition of a singly labeled dideoxynucleoside triphosphate to a singly labeled polynucleotide or by ligation of two singly labeled polynucleotides. Detection of fluorescence resonance energy transfer upon denaturation indicates the presence of the target. Kits are also provided. The method is particularly applicable to genotyping.

  11. Nanostructure Modified Microelectrode for Electrochemical Detection of Dopamine with Ascorbic Acid and Uric Acid.

    PubMed

    Kim, Kyeong-Jun; Choi, Jin-Ha; Pyo, Su-Hyun; Yun, Kwang-Seok; Lee, Ji-Young; Choi, Jeong-Woo; Oh, Byung-Keun

    2016-03-01

    Dopamine (DA) is one kind of neurotransmitter in central nervous system which is indicator of neural disease. For this reason, determination of DA concentration in central nervous system is very important for early diagnosis of neural disease. In this study, we designed micro electrode array and fabricated by MEMS technology. Furthermore, we fabricated 3-D conducting nanostructure on electrode surface for enhanced sensitivity and selectivity due to increased surface area. Compared with macro and normal micro electrode, the 3-D nanostructure modified micro electrode shows better electrical performance. These surface modified pin type electrode was applied to detect low concentration of DA and successfully detect various concentration of DA from 100 μM to 1 μM with linear relationship in the presence of ascorbic acid and uric acid. From these results, our newly designed electrode shows possibility to be applied as brain biosensor for neural disease diagnosis such as Parkinson's diseases. PMID:27455760

  12. The thermo-hand method: evaluation of a new indicator pad for acid permeation of chemical protective gloves.

    PubMed

    Vo, Evanly; Nicholson, Jonathan; Gao, Pengfei; Zhuang, Zhenzhen; Berardinelli, Stephen P

    2003-01-01

    The thermo-hand method was developed to evaluate a new indicator pad for acid permeation through chemical protective gloves under in-use conditions (controlled conditions for the hand's skin temperature, hand movements, and relative humidity inside gloves). An indicator pad was used to detect both organic and inorganic acid permeation through glove materials. Breakthrough times for five types of gloves were determined and found to range from 5 to 308 min for propionic acid, from 4 to 293 min for acrylic acid, and from 15 min to >6 hours for HCl. Quantification was performed for propionic and acrylic acids following solvent desorption and gas chromatography. Both acids exhibited >99% adsorption (including the volume of acid, which reacted with an indicator to contribute the color change) on the pads at a spiking level of 1.8 micro L for each acid. Acid recovery for the system was calculated for each acid, with results ranging from 52-72% (RSD < or =4.0%) for both acids over the spiking range 0.2-1.8 micro L. The quantitative mass of the acids on the pads at the time of breakthrough detection ranged from 253-276 and 270-296 micro g/cm(2) for propionic acid and acrylic acid, respectively. The thermo-hand method and a new acid indicator pad together should be useful in detecting, collecting, and quantitatively analyzing acid permeation samples in the workplace. PMID:14674803

  13. Integrated sample-to-detection chip for nucleic acid test assays.

    PubMed

    Prakash, R; Pabbaraju, K; Wong, S; Tellier, R; Kaler, K V I S

    2016-06-01

    Nucleic acid based diagnostic techniques are routinely used for the detection of infectious agents. Most of these assays rely on nucleic acid extraction platforms for the extraction and purification of nucleic acids and a separate real-time PCR platform for quantitative nucleic acid amplification tests (NATs). Several microfluidic lab on chip (LOC) technologies have been developed, where mechanical and chemical methods are used for the extraction and purification of nucleic acids. Microfluidic technologies have also been effectively utilized for chip based real-time PCR assays. However, there are few examples of microfluidic systems which have successfully integrated these two key processes. In this study, we have implemented an electro-actuation based LOC micro-device that leverages multi-frequency actuation of samples and reagents droplets for chip based nucleic acid extraction and real-time, reverse transcription (RT) PCR (qRT-PCR) amplification from clinical samples. Our prototype micro-device combines chemical lysis with electric field assisted isolation of nucleic acid in a four channel parallel processing scheme. Furthermore, a four channel parallel qRT-PCR amplification and detection assay is integrated to deliver the sample-to-detection NAT chip. The NAT chip combines dielectrophoresis and electrostatic/electrowetting actuation methods with resistive micro-heaters and temperature sensors to perform chip based integrated NATs. The two chip modules have been validated using different panels of clinical samples and their performance compared with standard platforms. This study has established that our integrated NAT chip system has a sensitivity and specificity comparable to that of the standard platforms while providing up to 10 fold reduction in sample/reagent volumes. PMID:27165104

  14. Methods of refining and producing isomerized fatty acid esters and fatty acids from natural oil feedstocks

    DOEpatents

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.; Beltran, Leslie V.; Kunz, Linda A.; Pals, Tessa M.; Quinn, Jordan R; Behrends, Jr., Raymond T.; Bernhardt, Randal J.

    2016-07-05

    Methods are provided for refining natural oil feedstocks and producing isomerized esters and acids. The methods comprise providing a C4-C18 unsaturated fatty ester or acid, and isomerizing the fatty acid ester or acid in the presence of heat or an isomerization catalyst to form an isomerized fatty ester or acid. In some embodiments, the methods comprise forming a dibasic ester or dibasic acid prior to the isomerizing step. In certain embodiments, the methods further comprise hydrolyzing the dibasic ester to form a dibasic acid. In certain embodiments, the olefin is formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having unsaturated esters.

  15. A neutralization charge detection method for detecting ions under ambient and liquid-phase conditions.

    PubMed

    Chang, Ko-Keng; Cai, Yi-Hong; Chen, Chung-Hsuan; Wang, Yi-Sheng

    2016-04-14

    The neutralization charge detection method detects induction signals produced from the neutralization of electric charges of ions at metal surfaces. The signals are intense and can propagate through phase boundaries for detection. The detection method can detect ions under ambient and liquid-phase conditions with high senstivity and fast response time. PMID:26996136

  16. Sulfuric acid thermoelectrochemical system and method

    DOEpatents

    Ludwig, Frank A.

    1989-01-01

    A thermoelectrochemical system in which an electrical current is generated between a cathode immersed in a concentrated sulfuric acid solution and an anode immersed in an aqueous buffer solution of sodium bisulfate and sodium sulfate. Reactants consumed at the electrodes during the electrochemical reaction are thermochemically regenerated and recycled to the electrodes to provide continuous operation of the system.

  17. Sensor And Method For Detecting A Superstrate

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Cari, James R. (Inventor); Ngo, Phong H. (Inventor); Fink, Patrick W. (Inventor); Siekierski, James D. (Inventor)

    2006-01-01

    Method and apparatus are provided for determining a superstrate on or near a sensor, e.g., for detecting the presence of an ice superstrate on an airplane wing or a road. In one preferred embodiment, multiple measurement cells are disposed along a transmission line. While the present invention is operable with different types of transmission lines, construction details for a presently preferred coplanar waveguide and a microstrip waveguide are disclosed. A computer simulation is provided as part of the invention for predicting results of a simulated superstrate detector system. The measurement cells may be physically partitioned, nonphysically partitioned with software or firmware, or include a combination of different types of partitions. In one embodiment, a plurality of transmission lines are utilized wherein each transmission line includes a plurality of measurement cells. The plurality of transmission lines may be multiplexed with the signal from each transmission line being applied to the same phase detector. In one embodiment, an inverse problem method is applied to determine the superstrate dielectric for a transmission line with multiple measurement cells.

  18. Method for detecting viruses in aerosols.

    PubMed

    Wallis, C; Melnick, J L; Rao, V C; Sox, T E

    1985-11-01

    A simple method with poliovirus as the model was developed for recovering human enteric viruses from aerosols. Filterite filters (pore size, 0.45 micron; Filterite Corp., Timonium, Md.) moistened with glycine buffer (pH 3.5) were used for adsorbing the aerosolized virus. No virus passed the filter, even with air flow rates of 100 liters/min. Virus recovery from the filter was achieved by rapid elution with 800 ml of glycine buffer, pH 10. The virus in the primary eluate was reconcentrated by adjusting the pH to 3.5, adding AlCl3 to 0.0005 M, collecting the virus on a 0.25-micron-pore Filerite disk (diameter, 25 mm) and and eluting with 6 ml of buffer, pH 10. With this method, virus could be detected regularly in aerosols produced by flushing when 3 X 10(8) PFU of poliovirus were present in the toilet bowl. Poliovirus-containing fecal material from two of four infants who had recently received oral polio vaccine also yielded virus in the aerosols when feces containing 2.4 X 10(7) to 4.5 X 10(7) PFU of virus had been added to the toilet bowl. Persons infected with a variety of natural enteric viruses are known to excrete this amount of virus in their daily stools. PMID:3004329

  19. Method for detecting viruses in aerosols.

    PubMed Central

    Wallis, C; Melnick, J L; Rao, V C; Sox, T E

    1985-01-01

    A simple method with poliovirus as the model was developed for recovering human enteric viruses from aerosols. Filterite filters (pore size, 0.45 micron; Filterite Corp., Timonium, Md.) moistened with glycine buffer (pH 3.5) were used for adsorbing the aerosolized virus. No virus passed the filter, even with air flow rates of 100 liters/min. Virus recovery from the filter was achieved by rapid elution with 800 ml of glycine buffer, pH 10. The virus in the primary eluate was reconcentrated by adjusting the pH to 3.5, adding AlCl3 to 0.0005 M, collecting the virus on a 0.25-micron-pore Filerite disk (diameter, 25 mm) and and eluting with 6 ml of buffer, pH 10. With this method, virus could be detected regularly in aerosols produced by flushing when 3 X 10(8) PFU of poliovirus were present in the toilet bowl. Poliovirus-containing fecal material from two of four infants who had recently received oral polio vaccine also yielded virus in the aerosols when feces containing 2.4 X 10(7) to 4.5 X 10(7) PFU of virus had been added to the toilet bowl. Persons infected with a variety of natural enteric viruses are known to excrete this amount of virus in their daily stools. Images PMID:3004329

  20. Nucleic Acid Bioconjugates in Cancer Detection and Therapy.

    PubMed

    Patel, Pradeepkumar L; Rana, Niki K; Patel, Mayurbhai R; Kozuch, Stephen D; Sabatino, David

    2016-02-01

    Nucleoside- and nucleotide-based chemotherapeutics have been used to treat cancer for more than 50 years. However, their inherent cytotoxicities and the emergent resistance of tumors against treatment has inspired a new wave of compounds in which the overall pharmacological profile of the bioactive nucleic acid component is improved by conjugation with delivery vectors, small-molecule drugs, and/or imaging modalities. In this manner, nucleic acid bioconjugates have the potential for targeting and effecting multiple biological processes in tumors, leading to synergistic antitumor effects. Consequently, tumor resistance and recurrence is mitigated, leading to more effective forms of cancer therapy. Bioorthogonal chemistry has led to the development of new nucleoside bioconjugates, which have served to improve treatment efficacy en route towards FDA approval. Similarly, oligonucleotide bioconjugates have shown encouraging preclinical and clinical results. The modified oligonucleotides and their pharmaceutically active formulations have addressed many weaknesses of oligonucleotide-based drugs. They have also paved the way for important advancements in cancer diagnosis and treatment. Cancer-targeting ligands such as small-molecules, peptides, and monoclonal antibody fragments have all been successfully applied in oligonucleotide bioconjugation and have shown promising anticancer effects in vitro and in vivo. Thus, the application of bioorthogonal chemistry will, in all likelihood, continue to supply a promising pipeline of nucleic acid bioconjugates for applications in cancer detection and therapy. PMID:26663095

  1. Method for the separation of acid from acid-laden vapors

    SciTech Connect

    Hansen, L.J.

    1992-02-11

    This patent describes a method for the removal of hydrochloric or sulfuric acid from vapor laden with the acid. It comprises: contacting the acid-laden vapors with packing materials in a zone containing the packing materials wherein the packing materials are formed of polyester resin containing from about 5 to 40 weight percent aluminum sulfate crystals.

  2. Determination of ascorbic acid and carotenoids in food commodities by liquid chromatography with mass spectrometry detection.

    PubMed

    Frenich, A Garrido; Torres, M E Hernández; Vega, A Belmonte; Vidal, J L Martínez; Bolaños, P Plaza

    2005-09-21

    Two methods, one to determine ascorbic acid and one to determine lycopene and beta-carotene, in vegetables and fruits by liquid chromatography coupled with mass spectrometry (LC-MS) have been established. The chromatographic separation of the studied compounds and their MS parameters were optimized to improve selectivity and sensitivity. In both methods, separation was carried out with two coupled columns, first a C(18) and then a dC(18), using as mobile phase 70% methanol (0.005% acetic acid) and 30% acetic acid 0.05% for ascorbic acid determination and a mixture of methanol, tetrahydrofuran, and acetonitrile (60:30:10 v/v/v) for carotenoid analysis in isocratic mode. The molecular ion was selected for the quantification in selective ion monitoring (SIM) mode. Ascorbic acid was detected with electrospray ionization probe (ESI) in negative mode, while chemical ionization atmospheric pressure (APCI) in positive mode was used for the target carotenoids. The methodology for ascorbic acid analysis is based on an extraction with polytron using methanol and a mixture of methaphosphoric acid and acetic acid. Extraction of the carotenoids was carried out with tetrahydrofuran/methanol (1:1) (v/v). The proposed methods were applied, after their corresponding validations, to the analysis of four varieties of tomatoes, tomato in tin enriched and dried tomato, and to the analysis of mango and kiwi fruits, to compare the content in these compounds. Moreover, the influence of the process of freezing and the effect that the manipulation/preservation has in the content of ascorbic acid in tomato have also been studied. PMID:16159160

  3. DOM Based XSS Detecting Method Based on Phantomjs

    NASA Astrophysics Data System (ADS)

    Dong, Ri-Zhan; Ling, Jie; Liu, Yi

    Because malicious code does not appear in html source code, DOM based XSS cannot be detected by traditional methods. By analyzing the causes of DOM based XSS, this paper proposes a detection method of DOM based XSS based on phantomjs. This paper uses function hijacking to detect dangerous operation and achieves a prototype system. Comparing with existing tools shows that the system improves the detection rate and the method is effective to detect DOM based XSS.

  4. Preparation and optical performance detection of acid-leaching optical fiber image bundle

    NASA Astrophysics Data System (ADS)

    Zhou, Dechun; Yu, Fengxia; Tan, Fang; Lu, Jingjuan

    2009-05-01

    This article determines three kinds of materials: core and clad glass,cladding glass,acid-leaching glass and the match ability of physical and chemical performances of these materials is described.. The quantitative relationship between concentration, temperature, acid type and resolution time are studied to determine a series of suitable technical parameters. Many effective methods are identified to improve optical properties through a lager number of detecting and analyzing the properties of fiber image bundle, which lays a good foundation for wider application.

  5. Boron containing amino acid compounds and methods for their use

    SciTech Connect

    Glass, J.D.; Coderre, J.A.

    2000-01-25

    The present invention provides new boron containing amino acid compounds and methods for making these compounds by contacting melphalan or another nitrogen mustard derivative and sodium borocaptate. The present invention also provides a method of treating a mammal having a tumor by administering to the mammal a therapeutically effective amount of the new boron containing amino acid compounds.

  6. Boron containing amino acid compounds and methods for their use

    DOEpatents

    Glass, John D.; Coderre, Jeffrey A.

    2000-01-01

    The present invention provides new boron containing amino acid compounds and methods for making these compounds by contacting melphalan or another nitrogen mustard derivative and sodium borocaptate. The present invention also provides a method of treating a mammal having a tumor by administering to the mammal a therapeutically effective amount of the new boron containing amino acid compounds.

  7. Covalent protein crosslinks: general detection, quantitation, and characterization via modification with diphenylborinic acid.

    PubMed

    Graham, L; Gallop, P M

    1994-03-01

    Progressive crosslinking of proteins appears to be a general phenomenon in aging cells and tissues. Crosslinked proteins can form insoluble aggregates which become increasingly resistant to proteolysis as more crosslinks form. However, most evidence for progressive crosslinking with age is indirect, and little is known about the chemical mechanisms involved. We have therefore developed a method for detection and isolation of any type of stable covalent crosslink from protein hydrolysates which requires no prior knowledge of the molecular structure of whatever crosslink(s) may be present. It utilizes the specificity of the diphenylborinic acid reagent for alpha-amino acid groups and the chromatographic properties and uv absorbance of the crosslink derivatives. The method is demonstrated using eight different crosslinks from collagen and fibrin, and a general procedure is given for detection of any type of crosslink in a protein hydrolysate. PMID:8203759

  8. Detection of hepatitis C virus ribonucleic acid in the serum by amplification with polymerase chain reaction.

    PubMed Central

    Kato, N; Yokosuka, O; Omata, M; Hosoda, K; Ohto, M

    1990-01-01

    Hepatitis C virus (HCV) RNA was detected in the sera of patients with non-A, non-B chronic liver disease by polymerase chain reaction (PCR). RNA was extracted from the serum, reverse transcribed to cDNA, and amplified by PCR. With this method, 30 patients with non-A, non-B chronic liver disease and 10 healthy subjects were tested. HCV RNA was detected in 13 of 16 (81%) anti-HCV-positive patients and also in 7 of 14 (50%) anti-HCV-negative patients, but in none of 10 anti-HCV-negative healthy subjects. Specificity of this method was confirmed by direct sequencing of amplified cDNA segment. The nucleotide sequences (37 nucleotides) obtained from 15 patients showed only 68-78% homology compared with the prototype HCV nucleotide sequence. In addition, of 15 nucleotide sequences, there were 12 different types. But the translated amino acid sequences (12 amino acids) showed 83-100% homology compared with the prototype HCV amino acid sequence. These data suggest the majority of anti-HCV-positive patients are carriers of HCV. But to detect all the viremic patients, the anti-HCV antibody testing may be insufficient. Direct detection of HCV RNA may be useful in the study of virus replication and its association with various liver diseases. Images PMID:2173727

  9. Mutant fatty acid desaturase and methods for directed mutagenesis

    DOEpatents

    Shanklin, John; Whittle, Edward J.

    2008-01-29

    The present invention relates to methods for producing fatty acid desaturase mutants having a substantially increased activity towards substrates with fewer than 18 carbon atom chains relative to an unmutagenized precursor desaturase having an 18 carbon chain length specificity, the sequences encoding the desaturases and to the desaturases that are produced by the methods. The present invention further relates to a method for altering a function of a protein, including a fatty acid desaturase, through directed mutagenesis involving identifying candidate amino acid residues, producing a library of mutants of the protein by simultaneously randomizing all amino acid candidates, and selecting for mutants which exhibit the desired alteration of function. Candidate amino acids are identified by a combination of methods. Enzymatic, binding, structural and other functions of proteins can be altered by the method.

  10. Radio frequency detection assembly and method for detecting radio frequencies

    SciTech Connect

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  11. Method of analysis at the U.S. Geological Survey California Water Science Center, Sacramento Laboratory - determination of haloacetic acid formation potential, method validation, and quality-control practices

    USGS Publications Warehouse

    Zazzi, Barbara C.; Crepeau, Kathryn L.; Fram, Miranda S.; Bergamaschi, Brian A.

    2005-01-01

    An analytical method for the determination of haloacetic acid formation potential of water samples has been developed by the U.S. Geological Survey California Water Science Center Sacramento Laboratory. The haloacetic acid formation potential is measured by dosing water samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine. The haloacetic acids formed are bromochloroacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, tribromoacetic acid, and trichloroacetic acid. They are extracted, methylated, and then analyzed using a gas chromatograph equipped with an electron capture detector. Method validation experiments were performed to determine the method accuracy, precision, and detection limit for each of the compounds. Method detection limits for these nine haloacetic acids ranged from 0.11 to 0.45 microgram per liter. Quality-control practices include the use of blanks, quality-control samples, calibration verification standards, surrogate recovery, internal standard, matrix spikes, and duplicates.

  12. Validated UPLC method for determination of unbound bile acids in colesevelam HCl tablets.

    PubMed

    Vallapragada, Venkata Vivekanand; Inti, Gopichand; Vidiyala, Sudhakar Rao; Jadi, Sreeramulu

    2015-01-01

    A simple, precise and accurate gradient reverse-phase ultra-performance liquid chromatographic method was developed for the quantitative determination of bile acids [glycocholic acid (GCA), glycochenodeoxycholic acid (GCDA) and taurodeoxycholic acid (TDCA)) in in vitro bile acid-binding study of Welchol tablets. The method was developed using Phenomenex Kinetex C18 (50 × 2.10 mm, 1.7 µm) column with mobile phase containing a gradient mixture of solvent A consisting of 0.02 M tetrabutylammonium phosphate (pH 7.5) and solvent B consists acetonitrile. The eluted compounds were monitored at 210 nm and the runtime was within 2 min. The binding parameter constants of Colesevelam HCl tablets 625 mg were determined using the Langmuir approximation at pH 6.8 by UPLC. The method is selective and capable of detecting bile acids in the presence of placebo matrix. The method has been validated with a lower limit of quantitation of 0.01 mM for bile acids. A linear response function was established for the range of concentrations 0.01-30.0 mM (r > 0.99) for GCA, GCDA and TDCA. The intra- and interday precision values for bile acids met the acceptance as per Food and Drug Administrations guidelines. The developed method was applied to in vitro bile acid-binding studies of Colesevelam HCl tablets. PMID:24795077

  13. Method for Enzyme Design with Genetically Encoded Unnatural Amino Acids.

    PubMed

    Hu, C; Wang, J

    2016-01-01

    We describe the methodologies for the design of artificial enzymes with genetically encoded unnatural amino acids. Genetically encoded unnatural amino acids offer great promise for constructing artificial enzymes with novel activities. In our studies, the designs of artificial enzyme were divided into two steps. First, we considered the unnatural amino acids and the protein scaffold separately. The scaffold is designed by traditional protein design methods. The unnatural amino acids are inspired by natural structure and organic chemistry methods, and synthesized by either organic chemistry methods or enzymatic conversion. With the increasing number of published unnatural amino acids with various functions, we described an unnatural amino acids toolkit containing metal chelators, redox mediators, and click chemistry reagents. These efforts enable a researcher to search the toolkit for appropriate unnatural amino acids for the study, rather than design and synthesize the unnatural amino acids from the beginning. After the first step, the model enzyme was optimized by computational methods and directed evolution. Lastly, we describe a general method for evolving aminoacyl-tRNA synthetase and expressing unnatural amino acids incorporated into a protein. PMID:27586330

  14. [Capillary electrophoresis analysis for glyphosate, glufosinate and aminomethylphosphonic acid with laser-induced fluorescence detection].

    PubMed

    Cao, Liwei; Liang, Siliu; Tan, Xiaofang; Meng, Jianxin

    2012-12-01

    A sensitive analytical method was developed for the simultaneous determination of glyphosate, glufosinate and aminomethylphosphonic acid by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). 5-(4,6-Dichlorotriazinyl) amino fluorescein (DTAF) was successfully applied to label the herbicides. The optimal derivatization reaction was carried out in boric acid buffer of pH 9.5 at 30 degrees C for 40 min. The baseline separation of the three derivatives could be accomplished using 30 mmol/L boric acid, 15 mmol/L Brij-35 (pH 9.5) as the running buffer. The detection limits (S/N = 3) for the glyphosate, glufosinate and aminomethylphosphonic acid were 3.21, 6.14, 1.99 ng/kg, respectively. Finally, the method was successfully applied to the analysis of environmental samples, and the three compounds were measured without any interference from real samples. The recoveries of the compounds in these samples were 91.3% - 106.0%. The method has the advantages of easiness and sensitivity, and can meet the requirement of the determination of the herbicide and metabolite residues in the environmental samples. PMID:23593890

  15. Gallic Acid: Review of the Methods of Determination and Quantification.

    PubMed

    Fernandes, Felipe Hugo Alencar; Salgado, Hérida Regina Nunes

    2016-05-01

    Gallic acid (3,4,5 trihydroxybenzoic acid) is a secondary metabolite present in most plants. This metabolite is known to exhibit a range of bioactivities including antioxidant, antimicrobial, anti-inflammatory, and anticancer. There are various methods to analyze gallic acid including spectrometry, chromatography, and capillary electrophoresis, among others. They have been developed to identify and quantify this active ingredient in most biological matrices. The aim of this article is to review the available information on analytical methods for gallic acid, as well as presenting the advantages and limitations of each technique. PMID:26440222

  16. [Detection of sorbic acid in food by homemade micro-spectrometer analytical system].

    PubMed

    Chuan, Na; Xu, Yi; Chen, Gang; Wen, Zhong-quan; He, Li; Wen, Zhi-yu

    2012-08-01

    A homemade micro-spectrometer analytical system was developed for the quantitative determination of the sorbic acid in the food based on the photometric principle. And with the standard addition method it was applied to eliminate the interference coming from the food substrate. The detecting result illustrated a good relativity in the range of 0-10.0 mg x L(-1) with the linear correlation coefficient of 0.9989, and the sample recovery was 99.2%-99.5% with RSD of 0.58%. The micro-spectrometer analysis system has shown potential prospective application in the fields of rapid and high performance detection for food additives. PMID:23156802

  17. Concentration methods for high-resolution THz spectroscopy of nucleic-acid biomolecules and crystals

    NASA Astrophysics Data System (ADS)

    Brown, E. R.; Zhang, W.; Mendoza, E. A.; Kuznetsova, Y.; Brueck, S. R. J.; Rahman, M.; Norton, M. L.

    2012-03-01

    Biomolecules can exhibit low-lying vibrational modes in the THz region which are detectable in transmission given a strong molecular dipole moment and optical depth, and a spectrometer of adequate sensitivity. The nucleic acids are particularly interesting because of applications such as label-free gene assay, bio-agent detection, etc. However for nucleic acids, sample preparation and THz coupling are of paramount importance because of the strong absorption by liquid water and the small concentration of molecules present in physiological solutions. Concentration methods become necessary to make the THz vibrational modes detectable, either by concentrating the nucleic-acid sample itself in a small volume but large area, or by concentrating the THz radiation down to the volume of the sample. This paper summarizes one type of the first method: nanofluidic channel arrays for biological nucleic acids; and two types of the second method: (1) a circular-waveguide pinhole, and (2) a circular-waveguide, conical-horn coupling structure, both for DNA crystals. The first method has been demonstrated on a very short artificial nucleic acid [small-interfering (si) RNA (17-to-25 bp)] and a much longer, biological molecule [Lambda-phage DNA (48.5 kbp)]. The second method has been demonstrated on small (~100 micron) single crystals of DNA grown by the sitting-drop method.

  18. Compositions and method for controlling precipitation when acidizing sour wells

    SciTech Connect

    Dill, W.R.; Walker, M.L.

    1990-08-21

    This patent describes a method of treating a sour well penetrating a subterranean formation. It comprises: introducing into the well a treating fluid comprising an acid solution having a pH below 1.9, an iron sequestering agent comprising at least one compound selected from the group consisting of aminopolycarboxylic acids, hydroxycarboxylic acids, cyclic polyethers and derivatives of the acids and ethers, present in an amount of from about 0.25 to about 5 percent by weight of the acid solution, and a sulfide modifier comprising at least one compound selected from the group consisting of an aldehyde, acetal, hemiacetal and any other compound capable of forming aldehydes in the acid solution, present in an amount of from about 0.25 to about 5 percent of the acid solution; and treating the subterranean formation with the treating fluid.

  19. A method for analysis of vanillic acid in polar ice cores

    NASA Astrophysics Data System (ADS)

    Grieman, M. M.; Greaves, J.; Saltzman, E. S.

    2015-02-01

    Biomass burning generates a wide range of organic compounds that are transported via aerosols to the polar ice sheets. Vanillic acid is a product of conifer lignin combustion, which has previously been observed in laboratory and ambient biomass burning aerosols. In this study a method was developed for analysis of vanillic acid in melted polar ice core samples. Vanillic acid was chromatographically separated using reversed-phase liquid chromatography (HPLC) and detected using electrospray ionization-triple quadrupole mass spectrometry (ESI-MS/MS). Using a 100 μL injection loop and analysis time of 4 min, we obtained a detection limit of 77 ppt (parts per trillion by mass) and an analytical precision of ±10%. Measurements of vanillic acid in Arctic ice core samples from the Siberian Akademii Nauk core are shown as an example application of the method.

  20. Surface-crack detection by microwave methods

    NASA Technical Reports Server (NTRS)

    Feinstein, L.; Hruby, R.

    1967-01-01

    Microwave surface-crack detection system examines metallic surfaces with a noncontacting probe. The change in the microwave signal reflected from the surface under investigation is an indication of the existence of surface flaws. This technique can detect flaws and scratches as small as 100 microinches.

  1. Determination of acrylamide and acrylic acid by isocratic liquid chromatography with pulsed electrochemical detection.

    PubMed

    Casella, Innocenzo G; Pierri, Marianna; Contursi, Michela

    2006-02-24

    The electrochemical behaviour of the polycrystalline platinum electrode towards the oxidation/reduction of short-chain unsaturated aliphatic molecules such as acrylamide and acrylic acid was investigated in acidic solutions. Analytes were separated by reverse phase liquid chromatographic and quantified using a pulsed amperometric detection. A new two-step waveform, is introduced for detection of acrylamide and acrylic acid. Detection limits (LOD) of 20 nM (1. 4 microg/kg) and 45 nM (3.2 microg/kg) were determined in water solutions containing acrylamide and acrylic acid, respectively. Compared to the classical three-step waveform, the proposed two-step waveform shows favourable analytical performance in terms of LOD, linear range, precision and improved long-term reproducibility. The proposed analytical method combined with clean-up procedure accomplished by Carrez clearing reagent and subsequent extraction with a strong cation exchanger cartridges (SPE), was successfully used for the quantification of low concentrations of acrylamide in foodstuffs such as coffee and potato fries. PMID:16426623

  2. TiO2 optical sensor for amino acid detection

    NASA Astrophysics Data System (ADS)

    Tereshchenko, Alla; Viter, Roman; Konup, Igor; Ivanitsa, Volodymyr; Geveliuk, Sergey; Ishkov, Yuriy; Smyntyna, Valentyn

    2013-11-01

    A novel optical sensor based on TiO2 nanoparticles for Valine detection has been developed. In the presented work, commercial TiO2 nanoparticles (Sigma Aldrich, particle size 32 nm) were used as sensor templates. The sensitive layer was formed by a porphyrin coating on a TiO2 nanostructured surface. As a result, an amorphous layer between the TiO2 nanostructure and porphyrin was formed. Photoluminescence (PL) spectra were measured in the range of 370-900 nm before and after porphyrin application. Porphyrin adsorption led to a decrease of the main TiO2 peak at 510 nm and the emergence of an additional peak of high intensity at 700 nm. Absorption spectra (optical density vs. wavelenght, measured from 300 to 1100 nm) showed IR shift Sorret band of prophiryn after deposition on metal oxide. Adsorption of amino acid quenched PL emission, related to porphyrin and increased the intensity of the TiO2 emission. The interaction between the sensor surface and the amino acid leads to the formation of new complexes on the surface and results in a reduction of the optical activity of porphyrin. Sensitivity of the sensor to different concentrations of Valine was calculated. The developed sensor can determine the concentration of Valine in the range of 0.04 to 0.16 mg/ml.

  3. Labelfree fully electronic nucleic acid detection system based on a field-effect transistor device.

    PubMed

    Uslu, F; Ingebrandt, S; Mayer, D; Böcker-Meffert, S; Odenthal, M; Offenhäusser, A

    2004-07-15

    The labelfree detection of nucleic acid sequences is one of the modern attempts to develop quick, cheap and miniaturised hand-held devices for the future genetic testing in biotechnology and medical diagnostics. We present an approach to detect the hybridisation of DNA sequences using electrolyte-oxide-semiconductor field-effect transistors (EOSFETs) with micrometer dimensions. These semiconductor devices are sensitive to electrical charge variations that occur at the surface/electrolyte interface, i.e. upon hybridisation of oligonucleotides with complementary single-stranded (ss) oligonucleotides, which are immobilised on the oxide surface of the transistor gate. This method allows direct, time-resolved and in situ detection of specific nucleic acid binding events without any labelling. We focus on the detection mechanism of our sensors by using oppositely charged polyelectrolytes (PAH and PSS) subsequently attached to the transistor structures. Our results indicate that the sensor output is charge sensitive and distance dependent from the gate surface, which pinpoints the need for very defined surface chemistry at the device surface. The hybridisation of natural 19 base-pair sequences has been successfully detected with the sensors. In combination with nano-transistors a PCR free detection system might be feasible in future. PMID:15142607

  4. Online SERS Detection of the 20 Proteinogenic L-Amino Acids Separated by Capillary Zone Electrophoresis

    PubMed Central

    Negri, Pierre; Schultz, Zachary D.

    2014-01-01

    A sheath-flow surface-enhanced Raman scattering (SERS) detector is demonstrated to provide chemical information enabling identification of the 20 proteinogenic L-amino acids separated by capillary zone electrophoresis (CZE). Amino acids were used to illustrate the chemical specificity of SERS detection from structurally related molecules. Analysis of the SERS electropherograms obtained from the separation and sequential online detection of six groups of structurally related amino acids shows that our sheath-flow SERS detector is able to resolve the characteristic Raman bands attributed to the amine, carboxyl, and side chain constituents. The results demonstrate the chemical information available from our detector and also provide insight into the nature of the analyte interaction with the silver SERS substrate. The spectra extracted from the SERS electropherogram of a mixture containing the 20 proteinogenic L-amino acids show unique signatures characteristic to each amino acid, thus enabling identification. The results presented here demonstrate the potential of this sheath-flow SERS detector as a general purpose method for high throughput characterization and identification following separations of complex biomolecular mixtures. PMID:25268706

  5. Separation and detection of amino acid metabolites of Escherichia coli in microbial fuel cell with CE.

    PubMed

    Wang, Wei; Ma, Lihong; Lin, Ping; Xu, Kaixuan

    2016-07-01

    In this work, CE-LIF was employed to investigate the amino acid metabolites produced by Escherichia coli (E. coli) in microbial fuel cell (MFC). Two peptides, l-carnosine and l-alanyl-glycine, together with six amino acids, cystine, alanine, lysine, methionine, tyrosine, arginine were separated and detected in advance by a CE-LIF system coupled with a homemade spontaneous injection device. The injection device was devised to alleviate the effect of electrical discrimination for analytes during sample injection. All analytes could be completely separated within 8 min with detection limits of 20-300 nmol/L. Then this method was applied to analyze the substrate solution containing amino acid metabolites produced by E. coli. l-carnosine, l-alanyl-glycine, and cystine were used as the carbon, nitrogen, and sulfur source for the E. coli culture in the MFC to investigate the amino acid metabolites during metabolism. Two MFCs were used to compare the activity of metabolism of the bacteria. In the sample collected at the running time 200 h of MFC, the amino acid methionine was discovered as the metabolite with the concentrations 23.3 μg/L. PMID:27121957

  6. Fast and Sensitive Method for Determination of Domoic Acid in Mussel Tissue.

    PubMed

    Barbaro, Elena; Zangrando, Roberta; Barbante, Carlo; Gambaro, Andrea

    2016-01-01

    Domoic acid (DA), a neurotoxic amino acid produced by diatoms, is the main cause of amnesic shellfish poisoning (ASP). In this work, we propose a very simple and fast analytical method to determine DA in mussel tissue. The method consists of two consecutive extractions and requires no purification steps, due to a reduction of the extraction of the interfering species and the application of very sensitive and selective HILIC-MS/MS method. The procedural method was validated through the estimation of trueness, extract yield, precision, detection, and quantification limits of analytical method. The sample preparation was also evaluated through qualitative and quantitative evaluations of the matrix effect. These evaluations were conducted both on the DA-free matrix spiked with known DA concentration and on the reference certified material (RCM). We developed a very selective LC-MS/MS method with a very low value of method detection limit (9 ng g(-1)) without cleanup steps. PMID:26904720

  7. Fast and Sensitive Method for Determination of Domoic Acid in Mussel Tissue

    PubMed Central

    Barbaro, Elena; Zangrando, Roberta; Barbante, Carlo; Gambaro, Andrea

    2016-01-01

    Domoic acid (DA), a neurotoxic amino acid produced by diatoms, is the main cause of amnesic shellfish poisoning (ASP). In this work, we propose a very simple and fast analytical method to determine DA in mussel tissue. The method consists of two consecutive extractions and requires no purification steps, due to a reduction of the extraction of the interfering species and the application of very sensitive and selective HILIC-MS/MS method. The procedural method was validated through the estimation of trueness, extract yield, precision, detection, and quantification limits of analytical method. The sample preparation was also evaluated through qualitative and quantitative evaluations of the matrix effect. These evaluations were conducted both on the DA-free matrix spiked with known DA concentration and on the reference certified material (RCM). We developed a very selective LC-MS/MS method with a very low value of method detection limit (9 ng g−1) without cleanup steps. PMID:26904720

  8. The behavioral detection of binary mixtures of amino acids and their individual components by catfish.

    PubMed

    Valentincic, T; Kralj, J; Stenovec, M; Koce, A; Caprio, J

    2000-11-01

    The question of whether a binary mixture of amino acids is detected by fish as a unique odor or whether the qualities of the individual components are retained within the mixture was investigated in channel (Ictalurus punctatus) and brown bullhead (Ameiurus nebulosus) catfish, species that are highly similar in their olfactory receptor and behavioral responses to amino acid odorants. Catfish respond with greater appetitive food-searching (swimming) behavior to amino-acid-conditioned olfactory stimuli than to non-conditioned amino acids. In the present study, appetitive food-searching behavior was measured by counting the number of turns of the fish greater than 90 degrees within 90 s of stimulus onset and, in some tests, by video tracking. The two methods yielded highly correlated results. Channel catfish conditioned to a binary mixture composed of equimolar amino acids responded with searching behavior to the amino acid that produced the larger-amplitude electro-olfactogram (EOG) response as they did to the conditioned stimulus. In further studies, bullhead catfish were conditioned either to a binary mixture or to a single amino acid and tested to determine whether a binary mixture was detected as the component evoking the larger EOG response. In all initial tests (trials 1-3), the more stimulatory component of a binary mixture was not discriminated from the binary mixture; however, the less stimulatory component and all other amino acids tested were discriminated from the mixture. By increasing the concentration of the originally less potent component in a binary mixture, making it the more stimulatory compound, it was now detected as not significantly different from the binary mixture; however, the original more potent component (i.e. now the less potent stimulus) was detected as significantly different from the mixture. However, with 5-10 additional discrimination training trials, the less stimulatory component in a binary mixture influenced the perception of

  9. Immunochemical Assays and Nucleic-Acid Detection Techniques for Clinical Diagnosis of Prostate Cancer

    PubMed Central

    Kanyong, Prosper; Rawlinson, Sean; Davis, James

    2016-01-01

    Prostate cancer (PCa) is a significant cause of morbidity and mortality and the most common cancer in men in Europe, North America, and some parts of Africa. The established methods for detecting PCa are normally based on tests using Prostate Specific Antigen (PSA) in blood, Prostate cancer antigen 3 (PCA3) in urine and tissue Alpha-methylacyl-CoA racemase (AMACR) as tumour markers in patient samples. Prior to the introduction of PSA in clinics, prostatic acid phosphatase (PAP) was the most widely used biomarker. An early diagnosis of PCa through the detection of these biomarkers requires the availability of simple, reliable, cost-effective and robust techniques. Immunoassays and nucleic acid detection techniques have experienced unprecedented growth in recent years and seem to be the most promising analytical tools. This growth has been driven in part by the surge in demand for near-patient-testing systems in clinical diagnosis. This article reviews immunochemical assays, and nucleic-acid detection techniques that have been used to clinically diagnose PCa. PMID:26958088

  10. Direct determination of seleno-amino acids in biological tissues by anion-exchange separation and electrochemical detection.

    PubMed

    Cavalli, S; Cardellicchio, N

    1995-07-01

    Several studies have described the determination of selenium in protein extracts from tissues of marine or terrestrial animals, but have not identified the different chemical forms of selenium that are present. Selenium may be present as seleno-amino acids. Selenocysteine, for example, is a normal component of glutathione peroxidase, an antioxidant enzyme which may behave like other antioxidants, such as vitamin E, protecting tissues against methylmercury toxicity. The present study illustrates a method for the characterization of seleno-amino acids, such as selenocysteine and selenomethionine, in proteins extracted from the liver of marine mammals. The mechanism of detoxification of methylmercury, which involves seleno-compounds, is identified. The analytical determination was carried out using high-performance anion-exchange chromatography coupled with integrated pulsed amperometric detection (HPAEC-IPAD). This method allows the direct determination of underivatized amino acids, eliminating the procedure of pre- or postcolumn derivatization. The chromatographic separation was carried out on an anion-exchange column using a quaternary gradient elution. In order to optimize this method, interferences of amino acids and the influence of pH and ionic strength on the separation and electrochemical detection were studied. The IPAD response for the direct detection of amino acids is optimum at pH > 11. The detection limit (S/N = 3) for selenocysteine was found to be 450 micrograms/l. The application of this method for the identification of seleno-amino acids in protein hydrolysates is also shown. PMID:7640774

  11. STATISTICAL EVALUATION OF AN ANALYTICAL GC/MS METHOD FOR THE DETERMINATION OF LONG CHAIN FATTY ACIDS

    EPA Science Inventory

    In-depth evaluation of an analytical method to detect and quantify long chain fatty acids (C8 - C16) at trace level concentrations (25-1000 µg/l) is presented. The method requires derivatization of the acids with methanolic boron trifluoride, separation, and...

  12. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, Gary A [Kennewick, WA; Smith, Jeffrey W [Lancaster, OH; Ihle, Nathan C [Walla Walla, WA

    1984-01-01

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH).sub.2 to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with portland cement to form concrete.

  13. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, G.A.; Smith, J.W.; Ihle, N.C.

    1982-07-08

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH)/sub 2/ to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with Portland cement to form concrete.

  14. System and method for detecting cells or components thereof

    DOEpatents

    Porter, Marc D.; Lipert, Robert J.; Doyle, Robert T.; Grubisha, Desiree S.; Rahman, Salma

    2009-01-06

    A system and method for detecting a detectably labeled cell or component thereof in a sample comprising one or more cells or components thereof, at least one cell or component thereof of which is detectably labeled with at least two detectable labels. In one embodiment, the method comprises: (i) introducing the sample into one or more flow cells of a flow cytometer, (ii) irradiating the sample with one or more light sources that are absorbed by the at least two detectable labels, the absorption of which is to be detected, and (iii) detecting simultaneously the absorption of light by the at least two detectable labels on the detectably labeled cell or component thereof with an array of photomultiplier tubes, which are operably linked to two or more filters that selectively transmit detectable emissions from the at least two detectable labels.

  15. Principal component analysis and neural networks for detection of amino acid biosignatures

    NASA Astrophysics Data System (ADS)

    Dorn, Evan D.; McDonald, Gene D.; Storrie-Lombardi, Michael C.; Nealson, Kenneth H.

    2003-12-01

    We examine the applicability of Principal Component Analysis (PCA) and Artificial Neural Network (ANN) methods of data analysis to biosignature detection. These techniques show promise in classifying and simplifying the representation of patterns of amino acids resulting from biological and non-biological syntheses. PCA correctly identifies glycine and alanine as the amino acids contributing the most information to the task of discriminating biotic and abiotic samples. Trained ANNs correctly classify between 86.1 and 99.5% of a large set of amino acid samples as biotic or abiotic. These and similar techniques are important in the design of automated data analysis systems for robotic missions to distant planetary bodies. Both techniques are robust with respect to noisy and incomplete data. Analysis of the performance of PCA and ANNs also lends insight into the localization of useful information within a particular data set, a feature that may be exploited in the selection of experiments for efficient mission design.

  16. [THE DETECTION OF CONTENT OF DIAGNOSTICALLY SIGNIFICANT FATTY ACIDS AND INDIVIDUAL TRIGLYCERIDES IN BIOLOGICAL MEDIUMS BASED ON INFRARED SPECTROMETRY].

    PubMed

    Kalinin, A V; Krasheninnikov, V N; Sviridov, A P; Titov, V N

    2015-11-01

    The content of clinically important fatty acids and individual triglycerides in food and biological mediums are traditionally detected by gas and fluid chromatography in various methodical modifications. The techniques are hard-to-get in laboratories of clinical biochemistry. The study was carried out to develop procedures and equipment for operative quantitative detection of concentration of fatty acids, primarily palmitic saturated fatty acid and oleic mono unsaturated fatty acid. Also detection was applied to sums ofpolyenoic (eicosapentaenoic and docosahexaenoic acid) fatty acids in biological mediums (cod-liver oil, tissues, blood plasma) using spectrometers of short-range infrared band of different types: with Fourier transform, diffraction and combined scattering. The evidences of reliable and reproducible quantitative detection offatty acids were received on the basis of technique of calibration (regression) by projection on latent structures using standard samples of mixtures of oils and fats. The evaluation is implemented concerning possibility of separate detection of content of palmitic and oleic triglycerides in mediums with presence of water The choice of technical conditions and mode of application of certain types of infrared spectrometers and techniques of their calibration is substantiated PMID:26999859

  17. Determination of free and amidated bile acids by high-performance liquid chromatography with evaporative light-scattering mass detection.

    PubMed

    Roda, A; Cerrè, C; Simoni, P; Polimeni, C; Vaccari, C; Pistillo, A

    1992-09-01

    A simple reverse phase high-performance liquid chromatographic method for a simultaneous analysis of free, glycine- and taurine-amidated bile acids is described. The resolution of ursodeoxycholic, cholic, chenodeocycholic, deoxycholic, and lithocholic acids, either free or amidated with glycine and taurine, is achieved using a C-18 octadecylsilane column (30 cm length, 4 micron particle size) with a gradient elution of aqueous methanol (65----75%) containing 15 mM ammonium acetate, pH 5.40, at 37 degrees C. The separated bile acids are detected with a new evaporative light-scattering mass detector and by absorbance at 200 nm. A complete resolution of the 16 bile acids, including the internal standard nor-deoxycholic acid, is obtained within 55 min. Using the light-scattering mass detector, amidated bile acids and, for the first time, free bile acids can be detected with similar detection limits in the order of 2-7 nmol. The new detector improves the baseline and the signal-to-noise ratio over the UV detection as it is not affected by impurities present in the samples with higher molar absorptivity than bile acids or by the change in the mobile phase composition during the gradient. The method fulfills all the standard requirements of precision and accuracy and the linearity of the mass detector is over 5 decade the detection limit. The new method has been used for the direct analysis of bile acid in stools and bile with only a preliminary clean-up procedure using a C-18 reverse phase extraction. PMID:1402406

  18. Modified semiautomated method for free fatty acids in serum.

    PubMed Central

    Crane, B; Lane, C

    1977-01-01

    Modifications have been made to the reagent system of the semiautomated method for the determination of plasma free fatty acids by Baird et al. (1967), and results are reported of investigations into parameters affecting sensitivity and analytical range. PMID:599188

  19. Method for producing iron-based acid catalysts

    SciTech Connect

    Farcasiu, M.; Kathrein, H.; Kaufman, P.B.; Diehl, J.R.

    1998-04-01

    A method for preparing an acid catalyst with a long shelf-life is described. Crystalline iron oxides are doped with lattice compatible metals which are heated with halogen compounds at elevated temperatures.

  20. Immunochemical detection of serum prostatic acid phosphatase. Methodology and clinical evaluation.

    PubMed

    Chu, T M; Wang, M C; Scott, W W; Gibbons, R P; Johnson, D E; Schmidt, J D; Loening, S A; Prout, G R; Murphy, G P

    1978-01-01

    An immunochemical method for detection of prostatic acid prosphatase is described. Purified acid phosphatase was isolated from cancerous human prostate. A specific antiserum to the purified enzyme was produced in rabbits. The antiserum to postatic acid phosphatase did not react with acid phosphatase originating from other tissues. A counter immunolectrophoresis, utilizing the specific antibodies and a chemical staining technique, has been developed and clinically evaluated. Sera from patients with prostatic carcinoma (6/20 of stage B, 27/49 of stage C, and 98/125 of stage D) gave positive results. Sera from 19 patients with benign prostatic hypertrophy, from 89 patients with other tumors, from 12 patients with Gaucher's disease, from 107 healthy volunteers, and from 50 normal age-matched men all gave negative results. The sensitivity of this method was 0.4 IU of enzyme activity or 20 ng per ml of prostatic acid phosphatase protein. Further clinical evaluation of patients in the early stage of prostatic cancer and of patients undergoing chemotherapy is in progress. PMID:75196

  1. Nuclear material detection apparatus and method

    DOEpatents

    Jones, James L.; Hoggan, Jerry M.; Harker, Yale D.; Yoon, Woo Y.; Johnson, Larry O.

    2006-11-28

    A device for detecting photonuclear-induced neutrons is described herein. One embodiment of the device may comprise a neutron detector and a detection circuit. The neutron detector may comprise a detector output. The detection circuit may be operatively connected to the detector output and may comprise an amplifier, a low-pass filter, and a high pass filter. The amplifier may comprise an amplifier input and an amplifier output. The amplifier input may be being operatively connected to the detector output. The low-pass filter may comprise a low-pass filter input and a low-pass filter output. The low-pass filter input may be operatively connected to the amplifier output. The high-pass filter may comprise a high-pass filter input and a high-pass filter output. The high-pass filter input may be operatively connected to the amplifier output.

  2. Method for protecting plant life from acidic atmospheric pollutants

    SciTech Connect

    Lengyel, A.D.

    1986-10-14

    A method is described for treating a stand of coniferous trees growing by natural processes and exposed to an atmosphere containing inorganic nitric acid or nitrate compounds to improve the resistance of the trees to damage by acid rain. The method consists of foliarly applying at least one sugar selected from the group consisting of monosaccharides and disaccharides to the coniferous trees naturally growing in the stand exposed to the atmosphere.

  3. A comparison of moving object detection methods for real-time moving object detection

    NASA Astrophysics Data System (ADS)

    Roshan, Aditya; Zhang, Yun

    2014-06-01

    Moving object detection has a wide variety of applications from traffic monitoring, site monitoring, automatic theft identification, face detection to military surveillance. Many methods have been developed across the globe for moving object detection, but it is very difficult to find one which can work globally in all situations and with different types of videos. The purpose of this paper is to evaluate existing moving object detection methods which can be implemented in software on a desktop or laptop, for real time object detection. There are several moving object detection methods noted in the literature, but few of them are suitable for real time moving object detection. Most of the methods which provide for real time movement are further limited by the number of objects and the scene complexity. This paper evaluates the four most commonly used moving object detection methods as background subtraction technique, Gaussian mixture model, wavelet based and optical flow based methods. The work is based on evaluation of these four moving object detection methods using two (2) different sets of cameras and two (2) different scenes. The moving object detection methods have been implemented using MatLab and results are compared based on completeness of detected objects, noise, light change sensitivity, processing time etc. After comparison, it is observed that optical flow based method took least processing time and successfully detected boundary of moving objects which also implies that it can be implemented for real-time moving object detection.

  4. Rapid Methods for the Detection of General Fecal Indicators

    EPA Science Inventory

    Specified that EPA should develop: appropriate and effective indicators for improving detection in a timely manner of pathogens in coastal waters appropriate, accurate, expeditious and cost-effective methods for the timely detection of pathogens in coastal waters

  5. Methods and compositions for efficient nucleic acid sequencing

    DOEpatents

    Drmanac, Radoje

    2002-01-01

    Disclosed are novel methods and compositions for rapid and highly efficient nucleic acid sequencing based upon hybridization with two sets of small oligonucleotide probes of known sequences. Extremely large nucleic acid molecules, including chromosomes and non-amplified RNA, may be sequenced without prior cloning or subcloning steps. The methods of the invention also solve various current problems associated with sequencing technology such as, for example, high noise to signal ratios and difficult discrimination, attaching many nucleic acid fragments to a surface, preparing many, longer or more complex probes and labelling more species.

  6. Methods and compositions for efficient nucleic acid sequencing

    DOEpatents

    Drmanac, Radoje

    2006-07-04

    Disclosed are novel methods and compositions for rapid and highly efficient nucleic acid sequencing based upon hybridization with two sets of small oligonucleotide probes of known sequences. Extremely large nucleic acid molecules, including chromosomes and non-amplified RNA, may be sequenced without prior cloning or subcloning steps. The methods of the invention also solve various current problems associated with sequencing technology such as, for example, high noise to signal ratios and difficult discrimination, attaching many nucleic acid fragments to a surface, preparing many, longer or more complex probes and labelling more species.

  7. Comparison of methods for acid quantification: impact of resist components on acid-generating efficiency

    NASA Astrophysics Data System (ADS)

    Cameron, James F.; Fradkin, Leslie; Moore, Kathryn; Pohlers, Gerd

    2000-06-01

    Chemically amplified deep UV (CA-DUV) positive resists are the enabling materials for manufacture of devices at and below 0.18 micrometer design rules in the semiconductor industry. CA-DUV resists are typically based on a combination of an acid labile polymer and a photoacid generator (PAG). Upon UV exposure, a catalytic amount of a strong Bronsted acid is released and is subsequently used in a post-exposure bake step to deprotect the acid labile polymer. Deprotection transforms the acid labile polymer into a base soluble polymer and ultimately enables positive tone image development in dilute aqueous base. As CA-DUV resist systems continue to mature and are used in increasingly demanding situations, it is critical to develop a fundamental understanding of how robust these materials are. One of the most important factors to quantify is how much acid is photogenerated in these systems at key exposure doses. For the purpose of quantifying photoacid generation several methods have been devised. These include spectrophotometric methods, ion conductivity methods and most recently an acid-base type titration similar to the standard addition method. This paper compares many of these techniques. First, comparisons between the most commonly used acid sensitive dye, tetrabromophenol blue sodium salt (TBPB) and a less common acid sensitive dye, Rhodamine B base (RB) are made in several resist systems. Second, the novel acid-base type titration based on the standard addition method is compared to the spectrophotometric titration method. During these studies, the make up of the resist system is probed as follows: the photoacid generator and resist additives are varied to understand the impact of each of these resist components on the acid generation process.

  8. Nondestructive methods for early detection of damage to living plants

    NASA Astrophysics Data System (ADS)

    Fateyeva, Natalya L.; Matvienko, Gennadii G.; Shul'gina, Lidia A.

    2004-10-01

    As a result of the accomplish experiments determine, that by a method of a laser-induced fluorescence of chlorophyll it is possible to spot for cedar an early stage of the stressful factor, bound with presence in ground <>. In our case the laboratory researches provided learning a quantitative contents chlorophyll for plants found in normal and stressful conditions on a basis spectrophotometrical of a method. Natural measurement the observations behind dynamics of a photosynthetic state means of wood plants in vivo enable. For an estimation of this state the fluorescence of chlorophyll on wavelength 685 and 740 nm was used. The optical model of a green leaf was developed for methods of a laser-induced fluorescence of chlorophyll. A experiments series on remote research of processes violation of mineral power supply and exchange in plants is carried spent. Was considered the change of the ratios of intensity of a fluorescence of chlorophyll and carotenoids at deficiency. Was designed technique for detection infringement processes of mineral nutrition and change surveyed acidity grounds on laser-induce fluorescent responses of deciduous plants.

  9. Compositions and methods for detecting Noonan syndrome

    DOEpatents

    Gelb, Bruce D.; Tartaglia, Marco; Pennacchio, Len

    2012-07-17

    Diagnostic and therapeutic applications for Noonan Syndrome are described. The diagnostic and therapeutic applications are based on certain mutations in a RAS-specific guanine nucleotide exchange factor gene SOS1 or its expression product. The diagnostic and therapeutic applications are also based on certain mutations in a serine/threonine protein kinase gene RAF1 or its expression product thereof. Also described are nucleotide sequences, amino acid sequences, probes, and primers related to RAF1 or SOS1, and variants thereof, as well as host cells expressing such variants.

  10. New method for the estimation of platelet ascorbic acid

    PubMed Central

    Lloyd, J. V.; Davis, P. S.; Lander, Harry

    1969-01-01

    Present techniques for the estimation of platelet ascorbic acid allow interference by other substances in the sample. A new and more specific method of analysis is presented. The proposed method owes its increased specificity to resolution of the extract by thin-layer chromatography. By this means ascorbic acid is separated from other reducing substances present. The separated ascorbic acid is eluted from the thin layer and estimated by a new and very sensitive procedure: ascorbic acid is made to react with ferric chloride and the ferrous ions so formed are estimated spectrophotometrically by the coloured derivative which they form with tripyridyl-Striazine. Results obtained with normal blood platelets were consistently lower than simultaneous determinations by the dinitrophenylhydrazine (DNPH) method. PMID:5798633

  11. Enzyme-free detection and quantification of double-stranded nucleic acids.

    PubMed

    Feuillie, Cécile; Merheb, Maxime Mohamad; Gillet, Benjamin; Montagnac, Gilles; Hänni, Catherine; Daniel, Isabelle

    2012-08-01

    We have developed a fully enzyme-free SERRS hybridization assay for specific detection of double-stranded DNA sequences. Although all DNA detection methods ranging from PCR to high-throughput sequencing rely on enzymes, this method is unique for being totally non-enzymatic. The efficiency of enzymatic processes is affected by alterations, modifications, and/or quality of DNA. For instance, a limitation of most DNA polymerases is their inability to process DNA damaged by blocking lesions. As a result, enzymatic amplification and sequencing of degraded DNA often fail. In this study we succeeded in detecting and quantifying, within a mixture, relative amounts of closely related double-stranded DNA sequences from Rupicapra rupicapra (chamois) and Capra hircus (goat). The non-enzymatic SERRS assay presented here is the corner stone of a promising approach to overcome the failure of DNA polymerase when DNA is too degraded or when the concentration of polymerase inhibitors is too high. It is the first time double-stranded DNA has been detected with a truly non-enzymatic SERRS-based method. This non-enzymatic, inexpensive, rapid assay is therefore a breakthrough in nucleic acid detection. PMID:22695500

  12. Methods and systems for detection of radionuclides

    DOEpatents

    Coates, Jr., John T.; DeVol, Timothy A.

    2010-05-25

    Disclosed are materials and systems useful in determining the existence of radionuclides in an aqueous sample. The materials provide the dual function of both extraction and scintillation to the systems. The systems can be both portable and simple to use, and as such can beneficially be utilized to determine presence and optionally concentration of radionuclide contamination in an aqueous sample at any desired location and according to a relatively simple process without the necessity of complicated sample handling techniques. The disclosed systems include a one-step process, providing simultaneous extraction and detection capability, and a two-step process, providing a first extraction step that can be carried out in a remote field location, followed by a second detection step that can be carried out in a different location.

  13. Colorimetric Detection of Cadmium Ions Using DL-Mercaptosuccinic Acid-Modified Gold Nanoparticles.

    PubMed

    Chen, Na; Chen, Jun; Yang, Jing-Hua; Bai, Lian-Yang; Zhang, Yu-Ping

    2016-01-01

    A colorimetric assay has been developed for detection of Cd²⁺ utilizing DL-mercaptosuccinic acid-modified gold nanoparticles (MSA-AuNPs). The method showed good selectivity for Cd²⁺ over other metal ions. As a result, the linear relationships (r > 0.9606) between concentration 0.07 mM and 0.20 mM for cadmium ion were obtained. The detection limit was as low as 0.07 mM by the naked eye. The effect of pH on the aggregation was optimized. The MSA-AuNPs probe could be used to detect Cd²⁺ in an aqueous solution based on the aggregation-induced color change of MSA-AuNPs. PMID:27398533

  14. Method for detection of extremely low concentration

    DOEpatents

    Andresen, Brian D.; Miller, Fred S.

    2002-01-01

    An ultratrace detector system for hand-held gas chromatography having high sensitivity, for example, to emissions generated during production of weapons, biological compounds, drugs, etc. The detector system is insensitive to water, air, helium, argon, oxygen, and CO.sub.2. The detector system is basically composed of a hand-held capillary gas chromatography (GC), an insulated heated redox-chamber, a detection chamber, and a vapor trap. For example, the detector system may use gas phase redox reactions and spectral absorption of mercury vapor. The gas chromatograph initially separates compounds that percolate through a bed of heated mercuric oxide (HgO) in a silica--or other metal--aerogel material which acts as an insulator. Compounds easily oxidized by HgO liberate atomic mercury that subsequently pass through a detection chamber which includes a detector cell, such as quartz, that is illuminated with a 254 nm ultra-violet (UV) mercury discharge lamp which generates the exact mercury absorption bands that are used to detect the liberated mercury atoms. Atomic mercury strongly absorbs 254 nm energy is therefore a specific signal for reducing compounds eluting from the capillary GC, whereafter the atomic mercury is trapped for example, in a silicon-aerogel trap.

  15. Method of detecting and counting bacteria

    NASA Technical Reports Server (NTRS)

    Picciolo, G. L.; Chappelle, E. W. (Inventor)

    1976-01-01

    An improved method is provided for determining bacterial levels, especially in samples of aqueous physiological fluids. The method depends on the quantitative determination of bacterial adenosine triphosphate (ATP) in the presence of nonbacterial ATP. The bacterial ATP is released by cell rupture and is measured by an enzymatic bioluminescent assay. A concentration technique is included to make the method more sensitive. It is particularly useful where the fluid to be measured contains an unknown or low bacteria count.

  16. Detection of acid moisture in photovoltaic modules using a dual wavelength pH-sensitive fluorescent dye

    NASA Astrophysics Data System (ADS)

    Asaka, Takashi; Iwami, Kentaro; Taguchi, Atsushi; Umeda, Norihiro; Masuda, Atsushi

    2014-01-01

    The formation of acetic acid via the penetration of moisture into ethylene vinyl acetate (EVA) in photovoltaic (PV) modules is cited as the main reason for PV modules’ degradation. Currently, there is no effective method for detecting acetic moisture in PV modules. We proposed a simple method for detecting acid moisture in PV modules using a dual-wavelength pH-sensitive dye that measures pH by the ratio of the intensities of two peaks in the fluorescence spectra of the dye. We detected the pH change caused by acetic acid with the change in the intensity ratio of the fluorescence spectra of the dried dye. Furthermore, we observed that the dry fluorescent dye is heat resistant to withstand the lamination process for the manufacturing of PV modules, and has good long-term durability.

  17. A Sensitive Peptide Nucleic Acid Probe Assay for Detection of BRAF V600 Mutations in Melanoma.

    PubMed

    Chen, Tai-Long; Chang, John Wen-Cheng; Hsieh, Jia-Juan; Cheng, Hsin-Yi; Chiou, Chiuan-Chian

    Mutated v-Raf murine sarcoma viral oncogene homolog B (BRAF) is an important biomarker for the prediction of therapeutic efficacy of several anticancer drugs. The detection of BRAF mutation faces two challenges: Firstly, there are multiple types of mutations, and secondly, tumor samples usually contain various amounts of wild-type, normal tissues. Here, we describe a newly established method for sensitive detection of multiple types of BRAF V600 mutations in excess wild-type background. The method introduced a fluorophore-tagged peptide nucleic acid (PNA) to serve as both polymerase chain reaction (PCR) clamp and sensor probe, which inhibited the amplification of wild-type templates during PCR and revealed multiple types of mutant signals during melting analysis. We demonstrated the design and optimization process of the method, and applied it in the detection of BRAF mutations in 49 melanoma samples. This PNA probe assay method detected three types of mutations in 17 samples, and was much more sensitive than conventional PCR plus Sanger sequencing. PMID:27566656

  18. System and method for detecting gas

    SciTech Connect

    Chow, Oscar Ken; Moulthrop, Lawrence Clinton; Dreier, Ken Wayne; Miller, Jacob Andrew

    2010-03-16

    A system to detect a presence of a specific gas in a mixture of gaseous byproducts comprising moisture vapor is disclosed. The system includes an electrochemical cell, a transport to deliver the mixture of gaseous byproducts from the electrochemical cell, a gas sensor in fluid communication with the transport, the sensor responsive to a presence of the specific gas to generate a signal corresponding to a concentration of the specific gas, and a membrane to prevent transmission of liquid moisture, the membrane disposed between the transport and the gas sensor.

  19. Method for early detection of infectious mononucleosis

    DOEpatents

    Willard, K.E.

    1982-08-10

    Early detection of infectious mononucleosis is carried out using a sample of human blood by isolating and identifying the presence of Inmono proteins in the sample from a two-dimensional protein map with the proteins being characterized by having isoelectric banding as measured in urea of about -16 to -17 with respect to certain isoelectric point standards and molecular mass of about 70 to 75 K daltons as measured in the presence of sodium dodecylsulfate containing polyacrylamide gels, the presence of the Inmono proteins being correlated with the existence of infectious mononucleosis.

  20. Molecular detection of harmful algal blooms (HABs) using locked nucleic acids and bead array technology

    PubMed Central

    Diaz, Mara R.; Jacobson, James W.; Goodwin, Kelly D.; Dunbar, Sherry A.; Fell, Jack W.

    2010-01-01

    Harmful algal blooms (HABs) are a serious public health risk in coastal waters. As the intensity and frequency of HABs continue to rise, new methods of detection are needed for reliable identification. Herein, we developed a high-throughput, multiplex, bead array technique for the detection of the dinoflagellates Karenia brevis and Karenia mikimotoi. The method combined the Luminex detection system with two novel technologies: locked nucleic acid–modified oligonucleotides (LNA) and Mirus Label IT® nucleic acid technology. To study the feasibility of the method, we evaluated the performance of modified and unmodified LNA probes with amplicon targets that were biotin labeled with two different strategies: direct chemical labeling (Mirus Label IT) versus enzymatic end-labeling (single biotinylated primer). The results illustrated that LNA probes hybridized to complementary single-stranded DNA with better affinity and displayed higher fluorescence intensities than unmodified oligonucleotide DNA probes. The latter effect was more pronounced when the assay was carried out at temperatures above 53°C degree. As opposed to the enzymatic 5′ terminal labeling technique, the chemical-labeling method enhanced the level of fluorescence by as much as ~83%. The detection limits of the assay, which were established with LNA probes and Mirus Label IT system, ranged from 0.05 to 46 copies of rRNA. This high-throughput method, which represents the first molecular detection strategy to integrate Luminex technology with LNA probes and Mirus Label IT, can be adapted for the detection of other HABs and is well suited for the monitoring of red tides at pre-blooming and blooming conditions. PMID:21165155

  1. Endotoxemia: methods of detection and clinical correlates.

    PubMed Central

    Hurley, J C

    1995-01-01

    As an assay for endotoxin, the Limulus amebocyte lysate assay has several desirable properties: sensitivity, specificity, and potential for adaptation to a quantitative format. Several modifications have been developed to enhance its potential for clinical application. The modifications that allow quantitative measurement of endotoxin and also improve its application to blood samples are described in this review. In fluids other than blood, the detection of endotoxin with the Limulus amebocyte lysate assay can be used as an aid to identify the presence of gram-negative bacteria, and the assay has established utility. With blood, however, there are a range of factors that interfere with the detection of endotoxemia and there are disparate views with respect to the diagnostic and prognostic significance of the test results. In general, the clinical significance of the finding of endotoxemia broadly parallels the frequency and importance of gram-negative sepsis in the patient groups studied and a decline in endotoxin levels accompanies clinical improvement. However, with therapies designed to reduce levels of endotoxin, or to antagonize its effects, it is unclear whether clinical improvement occurs as a consequence of changes in the levels of endotoxemia. PMID:7621402

  2. Polarization sensitive optical coherence tomography detection method

    SciTech Connect

    Everett, M J; Sathyam, U S; Colston, B W; DaSilva, L B; Fried, D; Ragadio, J N; Featherstone, J D B

    1999-05-12

    This study demonstrates the potential of polarization sensitive optical coherence tomography (PS-OCT) for non-invasive in vivo detection and characterization of early, incipient caries lesions. PS-OCT generates cross-sectional images of biological tissue while measuring the effect of the tissue on the polarization state of incident light. Clear discrimination between regions of normal and demineralized enamel is first shown in PS-OCT images of bovine enamel blocks containing well-characterized artificial lesions. High-resolution, cross-sectional images of extracted human teeth are then generated that clearly discriminate between the normal and carious regions on both the smooth and occlusal surfaces. Regions of the teeth that appeared to be demineralized in the PS-OCT images were verified using histological thin sections examined under polarized light microscopy. The PS-OCT system discriminates between normal and carious regions by measuring the polarization state of the back-scattered 1310 nm light, which is affected by the state of demineralization of the enamel. Demineralization of enamel increases the scattereing coefficient, thus depolarizing the incident light. This study shows that PS-OCT has great potential for the detection, characterization, and monitoring of incipient caries lesions.

  3. Detection methods and performance criteria for genetically modified organisms.

    PubMed

    Bertheau, Yves; Diolez, Annick; Kobilinsky, André; Magin, Kimberly

    2002-01-01

    Detection methods for genetically modified organisms (GMOs) are necessary for many applications, from seed purity assessment to compliance of food labeling in several countries. Numerous analytical methods are currently used or under development to support these needs. The currently used methods are bioassays and protein- and DNA-based detection protocols. To avoid discrepancy of results between such largely different methods and, for instance, the potential resulting legal actions, compatibility of the methods is urgently needed. Performance criteria of methods allow evaluation against a common standard. The more-common performance criteria for detection methods are precision, accuracy, sensitivity, and specificity, which together specifically address other terms used to describe the performance of a method, such as applicability, selectivity, calibration, trueness, precision, recovery, operating range, limit of quantitation, limit of detection, and ruggedness. Performance criteria should provide objective tools to accept or reject specific methods, to validate them, to ensure compatibility between validated methods, and be used on a routine basis to reject data outside an acceptable range of variability. When selecting a method of detection, it is also important to consider its applicability, its field of applications, and its limitations, by including factors such as its ability to detect the target analyte in a given matrix, the duration of the analyses, its cost effectiveness, and the necessary sample sizes for testing. Thus, the current GMO detection methods should be evaluated against a common set of performance criteria. PMID:12083279

  4. Fast analysis of amino acids in wine by capillary electrophoresis with laser-induced fluorescence detection.

    PubMed

    Mandrioli, Roberto; Morganti, Emanuele; Mercolini, Laura; Kenndler, Ernst; Raggi, Maria A

    2011-10-01

    A fast analytical method has been developed for the determination of nine amino acids, together with serotonin, in wine samples of different origin and vintage. The method is based on capillary electrophoresis coupled to laser-induced fluorescence detection. Separation was obtained by using a fused-silica capillary (75 μm id, 74.0 cm total length, 60.0 cm length to detector) and a background electrolyte composed of carbonate buffer (20 mM, pH 9.2), applying a 20 kV voltage. Direct hydrodynamic injection of wine samples was made after an original microwave-assisted derivatisation step with 5-(4,6-dichlorotriazinyl)aminofluorescein. Fluorescence was induced by an Ar-Ion laser, exciting at 488 nm. Good linearity (r(2) >0.9990) was obtained for all considered analytes and sensitivity was also good, with limits of detection in the 7-50 ng/mL range. The method was successfully applied for the analysis of commercial Italian wines and thus seems to be suitable for the determination of the relevant amino acids and serotonin, providing good results in terms of accuracy and precision, together with the advantage of a very fast, microwave-assisted derivatisation procedure. Future applications of the method are planned to check for wine adulterations and commercial frauds. PMID:21922500

  5. A modified colorimetric method for phytic acid analysis in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A quantitative, reproducible, and efficient phytic acid assay procedure is needed to screen breeding populations and support genetic studies in soybeans. The objective of this study was to modify the colorimetric Wade reagent method and compare the accuracy and applicability of this new method in de...

  6. Method to produce succinic acid from raw hydrolysates

    DOEpatents

    Donnelly, Mark I.; Sanville-Millard, Cynthia Y.; Nghiem, Nhuan Phu

    2004-06-01

    A method for producing succinic acid from industrial-grade hydrolysates is provided, comprising supplying an organism that contains mutations for the genes ptsG, pflB, and ldhA, allowing said organism to accumulate biomass, and allowing said organism to metabolize the hydrolysate. Also provided is a bacteria mutant characterized in that it produces succinic acid from substrate contained in industrial-grade hydrolysate in a ratio of between 0.6:1 and 1.3:1 succinic acid to substrate.

  7. Method and compositions for detecting of bloodstains using fluorescin-fluorescein reaction

    DOEpatents

    Di Benedetto, John; Kyle, Kevin; Boan, Terry; Marie, Charlene

    2004-02-17

    A method, compositions and kit are set forth for detecting blood stains. A reactant solution includes fluorescin solubilized (reduced) in acetic acid in ethanol. The solution may be buffered to a pH of approximately 9. After spraying the reactant solution on the suspected area an oxidizer is applied to promote the fluorescin to fluorescein reaction with the blood. The reacted fluorescein is then detected through luminescence for capture by photography.

  8. Amino acid profiling as a method of discovering biomarkers for early diagnosis of cancer.

    PubMed

    Simińska, Edyta; Koba, Marcin

    2016-06-01

    Cancer is one of the main causes of mortality in the world and its early detection significantly increases chances of patients' survival. High cancer mortality rate is caused mainly by late-stage diagnosis and lack of non-invasive and reliable methods for early diagnosis, such as plasma biomarkers. The incidence of cancers in the world still grows so it is crucial to develop a new, faster, high specificity and more sensitive diagnostic technologies. Several recent researchers indicate amino acids as a potential marker for cancer detection. An ideal cancer biomarker should be characterized by high specificity and sensitivity, reliability, ease of measurement and, what is important, ability to detect disease in its early stage. This study is focused on indicating metabolic amino acid profiling as a method of identifying biomarkers for cancer early detection and screening. Presented results are derived from the most recent studies where patients in early, often asymptomatic stages of disease constituted a large percentage of all the patients and, what is important, where researchers have observed alterations in these patients' amino acid profiles. This review is concentrated on analyzing studies on the most common cancers with high mortality rate. Inventing effective methods of early diagnosis is particularly important in case of such diseases. Research presented in this publication is focused on patients with lung, breast and colon cancer. In all analyzed cases, significant changes in the amino acid profile in cancer patients comparing to healthy controls were observed. This study indicates potential of amino acid profiling as method for early cancer detection. PMID:27033065

  9. Spectrophotometric method for the estimation of 6-aminopenicillanic acid.

    PubMed

    Shaikh, K; Talati, P G; Gang, D M

    1973-02-01

    A simple, rapid, and sensitive method is described whereby 6-aminopenicillanic acid can be spectrophotometrically determined in the presence of penicillins and their degradation products without prior separation. d-(+)-Glucosamine is used as reagent. The effect of such parameters as pH, temperature, and time of heating on the formation of the chromophore is described. The recommended range is from 25 to 250 mug of 6-aminopenicillanic acid. PMID:4364173

  10. COMPARISON OF FOUR SAMPLING METHODS FOR THE DETECTION OF SALMONELLA IN BROILER LITTER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three experiments were conducted to compare litter sampling methods for the detection of Salmonella. In Experiment 1, two sets of 25 chicks were challenged orally with a suspension of naladixic acid resistant Salmonella and wing banded, and an additional 25 nonchallenged chicks were placed into eac...

  11. Method for distinctive estimation of stored acidity forms in acid mine wastes.

    PubMed

    Li, Jun; Kawashima, Nobuyuki; Fan, Rong; Schumann, Russell C; Gerson, Andrea R; Smart, Roger St C

    2014-10-01

    Jarosites and schwertmannite can be formed in the unsaturated oxidation zone of sulfide-containing mine waste rock and tailings together with ferrihydrite and goethite. They are also widely found in process wastes from electrometallurgical smelting and metal bioleaching and within drained coastal lowland soils (acid-sulfate soils). These secondary minerals can temporarily store acidity and metals or remove and immobilize contaminants through adsorption, coprecipitation, or structural incorporation, but release both acidity and toxic metals at pH above about 4. Therefore, they have significant relevance to environmental mineralogy through their role in controlling pollutant concentrations and dynamics in contaminated aqueous environments. Most importantly, they have widely different acid release rates at different pHs and strongly affect drainage water acidity dynamics. A procedure for estimation of the amounts of these different forms of nonsulfide stored acidity in mining wastes is required in order to predict acid release rates at any pH. A four-step extraction procedure to quantify jarosite and schwertmannite separately with various soluble sulfate salts has been developed and validated. Corrections to acid potentials and estimation of acid release rates can be reliably based on this method. PMID:25178979

  12. Multimode nondestructive detecting method for high-speed rail defects

    NASA Astrophysics Data System (ADS)

    Sun, Mingjian; Cheng, Xingzhen; Wan, Guangnan; Liu, Ting; Fu, Ying; Wang, Yan

    2015-11-01

    It is very important to detect the surface defects of the high-speed rail for security concerns. A multimode detecting method, which integrates high resolution of optical image, high precision of photoacoustic detection and strong penetration of ultrasound detecting, is proposed for the rail defect detection. Utilizing the surface defect characteristics obtained from optical signal, the photoacoustic and ultrasound scanning region could be determined, and rail shallow and internal defect characteristics can be acquired subsequently. Eventually, fusing three modal signals mentioned above, the information of the entire rail defect, including type, extension trend and depth can be detected. It has been proved that the multimode method can improve the detecting efficiency, and enlarge the detection range in the meantime.

  13. Sciatica: Detection and Confirmation by New Method

    PubMed Central

    Nadkarni, Sunil

    2014-01-01

    We need to overcome limitations of present assessment and also integrate newer research in our work about sciatica. Inflammation induces changes in the DRG and nerve root. It sensitizes the axons. Nociceptor is a unique axon. It is pseudo unipolar: both its ends, central and peripheral, behave in similar fashion. The nerve in periphery which carries these axons may selectively become sensitive to mechanical pressure--“mechanosensitized,” as we coin the phrase. Many pain questionnaires are used and are effective in identifying neuropathic pain solely on basis of descriptors but they do not directly physically correlate nerve root and pain. A thorough neurological evaluation is always needed. Physical examination is not direct pain assessment but testing mobility of nerve root and its effect on pain generation. There is a dogmatic dominance of dermatomes in assessment of leg pain. They are unreliable. Images may not correlate with symptoms and pathology in about 28% of cases. Electrophysiology may be normal in purely inflamed nerve root. Palpation may help in such inflammatory setting to refine our assessment further. Confirmation of sciatica is done by selective nerve root block (SNRB) today but it is fraught with several complications and needs elaborate inpatient and operating room set up. We have used the unique property of the pseudo unipolar axon that both its ends have similar functional properties and so inject along its peripheral end sodium channel blockers to block the basic cause of the mechanosensitization namely upregulated sodium channels in the root or DRG. Thus using palpation we may be able to detect symptomatic nerve in stage of inflammation and with distal end injection, along same inflamed nerve we may be able to abolish and so confirm sciatica. Discussions of sciatica pain diagnosis tend to immediately shift and centre on the affected disc rather than the nerve. Theoretically it may be possible to detect the affected nerve by palpating the

  14. Methods for detection of ataxia telangiectasia mutations

    DOEpatents

    Gatti, Richard A.

    2005-10-04

    The present invention is directed to a method of screening large, complex, polyexonic eukaryotic genes such as the ATM gene for mutations and polymorphisms by an improved version of single strand conformation polymorphism (SSCP) electrophoresis that allows electrophoresis of two or three amplified segments in a single lane. The present invention also is directed to new mutations and polymorphisms in the ATM gene that are useful in performing more accurate screening of human DNA samples for mutations and in distinguishing mutations from polymorphisms, thereby improving the efficiency of automated screening methods.

  15. Method of Detecting Coliform Bacteria from Reflected Light

    NASA Technical Reports Server (NTRS)

    Vincent, Robert K. (Inventor)

    2014-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  16. Method for detection of antibodies for metallic elements

    DOEpatents

    Barrick, C.W.; Clarke, S.M.; Nordin, C.W.

    1993-11-30

    An apparatus and method for detecting antibodies specific to non-protein antigens. The apparatus is an immunological plate containing a plurality of plastic projections coated with a non-protein material. Assays utilizing the plate are capable of stabilizing the non-protein antigens with detection levels for antibodies specific to the antigens on a nanogram level. A screening assay with the apparatus allows for early detection of exposure to non-protein materials. Specifically metallic elements are detected. 10 figures.

  17. Method for detection of antibodies for metallic elements

    DOEpatents

    Barrick, Charles W.; Clarke, Sara M.; Nordin, Carl W.

    1993-11-30

    An apparatus and method for detecting antibodies specific to non-protein antigens. The apparatus is an immunological plate containing a plurality of plastic projections coated with a non-protein material. Assays utilizing the plate are capable of stabilizing the non-protein antigens with detection levels for antibodies specific to the antigens on a nanogram level. A screening assay with the apparatus allows for early detection of exposure to non-protein materials. Specifically metallic elements are detected.

  18. A numerical method of detecting singularity

    NASA Technical Reports Server (NTRS)

    Laporte, M.; Vignes, J.

    1978-01-01

    A numerical method is reported which determines a value C for the degree of conditioning of a matrix. This value is C = 0 for a singular matrix and has progressively larger values for matrices which are increasingly well-conditioned. This value is C sub = C max sub max (C defined by the precision of the computer) when the matrix is perfectly well conditioned.

  19. Detection of ferulic acid esterase production by Bacillus spp. and lactobacilli.

    PubMed

    Donaghy, J; Kelly, P F; McKay, A M

    1998-08-01

    The production of feruloyl esterase activity by Bacillus spp. and lactobacilli can be detected in an agarplate assay. The assay involves the substitution of the main carbon source in specific agar with ethyl ferulate. A number of Bacillus spp., predominantly B. subtilis strains, were found to exhibit feruloyl esterase activity by this method. Of the examined lactobacilli, Lb. fermentum (NCFB 1751) showed the highest level of ferulic acid esterase activity. The enzyme was released from harvested cells by sonication and showed pH and temperature optima of 6.5 and 30 degrees C respectively. PMID:9763694

  20. Wheat gluten amino acid composition analysis by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

    PubMed

    Rombouts, Ine; Lamberts, Lieve; Celus, Inge; Lagrain, Bert; Brijs, Kristof; Delcour, Jan A

    2009-07-17

    A simple accurate method for determining amino acid composition of wheat gluten proteins and their gliadin and glutenin fractions using high-performance anion-exchange chromatography with integrated pulsed amperometric detection is described. In contrast to most conventional methods, the analysis requires neither pre- or post-column derivatization, nor oxidation of the sample. It consists of hydrolysis (6.0M hydrochloric acid solution at 110 degrees C for 24h), evaporation of hydrolyzates (110 degrees C), and chromatographic separation of the liberated amino acids. Correction factors (f) accounted for incomplete cleavage of peptide bonds involving Val (f=1.07) and Ile (f=1.13) after hydrolysis for 24h and for Ser (f=1.32) losses during evaporation. Gradient conditions including an extra eluent (0.1M acetic acid solution) allowed multiple sequential sample analyses without risk of Glu contamination on the anion-exchange column. While gluten amino acid compositions by the present method were mostly comparable to those obtained by a conventional method involving oxidation, acid hydrolysis and post-column ninhydrin derivatization, the latter method underestimated Tyr, Val and Ile levels. Results for the other amino acids obtained by the different methods were linearly correlated (r>0.99, slope=1.03). PMID:19523641

  1. Localized surface plasmon resonance mercury detection system and methods

    DOEpatents

    James, Jay; Lucas, Donald; Crosby, Jeffrey Scott; Koshland, Catherine P.

    2016-03-22

    A mercury detection system that includes a flow cell having a mercury sensor, a light source and a light detector is provided. The mercury sensor includes a transparent substrate and a submonolayer of mercury absorbing nanoparticles, e.g., gold nanoparticles, on a surface of the substrate. Methods of determining whether mercury is present in a sample using the mercury sensors are also provided. The subject mercury detection systems and methods find use in a variety of different applications, including mercury detecting applications.

  2. Criteria For Evaluation of Proposed Protozoan Detection Methods

    EPA Science Inventory

    Currently, the only EPA approved method for detection and quantitation of protozoan cysts and oöcysts in source and drinking water, is the “ICR Protozoan Method for Detecting Giardia Cysts and Cryptosporidium Oöcysts in Water by a Fluorescent Antibody Procedure (ICR Microbial La...

  3. Ultra-high sensitivity radiation detection apparatus and method

    DOEpatents

    Gross, Kenneth C.; Valentine, John D.; Markum, Francis; Zawadzki, Mary; Dickerman, Charles

    1999-01-01

    A method and apparatus are provided to concentrate and detect very low levels of radioactive noble gases from the atmosphere. More specifically the invention provides a method and apparatus to concentrate xenon, krypton and radon in an organic fluid and to detect these gases by the radioactive emissions.

  4. Methods And Devices For Characterizing Duplex Nucleic Acid Molecules

    DOEpatents

    Akeson, Mark; Vercoutere, Wenonah; Haussler, David; Winters-Hilt, Stephen

    2005-08-30

    Methods and devices are provided for characterizing a duplex nucleic acid, e.g., a duplex DNA molecule. In the subject methods, a fluid conducting medium that includes a duplex nucleic acid molecule is contacted with a nanopore under the influence of an applied electric field and the resulting changes in current through the nanopore caused by the duplex nucleic acid molecule are monitored. The observed changes in current through the nanopore are then employed as a set of data values to characterize the duplex nucleic acid, where the set of data values may be employed in raw form or manipulated, e.g., into a current blockade profile. Also provided are nanopore devices for practicing the subject methods, where the subject nanopore devices are characterized by the presence of an algorithm which directs a processing means to employ monitored changes in current through a nanopore to characterize a duplex nucleic acid molecule responsible for the current changes. The subject methods and devices find use in a variety of applications, including, among other applications, the identification of an analyte duplex DNA molecule in a sample, the specific base sequence at a single nulceotide polymorphism (SNP), and the sequencing of duplex DNA molecules.

  5. [Pseudothrombocytopenia: incidence, causes and methods of detection].

    PubMed

    García Suárez, J; Merino, J L; Rodríguez, M; Velasco, A; Moreno, M C

    1991-06-01

    A prospective study of 20,761 routine clinical blood specimens was conducted in order to evaluate incidence and causes of pseudothrombocytopenia. All specimens were drawn in outpatient regimen and were analyzed by using the Coulter STKR autoanalyzer. The incidence of pseudothrombocytopenia was 0.15%, values clearly lower than others previously reported in hospitalized patients (1.9%). Of these patients, 72% had EDTA-induced platelet clumping sometimes associated to sodium citrate and 28% had spurious low platelet counts due to large platelets. No other causes of pseudothrombocytopenia were appreciated. It is important to remark that 49% of low platelet counts detected by the Coulter STKR have been due to pseudothrombocytopenia, and this instrument showed normal platelet and leukocyte histogram in 10% of these cases. Although time consuming these results confirm the necessity of preparation and examination of all blood smears presenting thrombocytopenia by automated cell-counting despite normal histograms. This approach would avoid erroneous diagnosis and dangerous medical or surgical therapy. A correlation of pseudothrombocytopenia with age, sex or clinical diagnosis were not found. PMID:1948538

  6. Laser pulse detection method and apparatus

    NASA Technical Reports Server (NTRS)

    Goss, Willis C. (Inventor); Janesick, James R. (Inventor)

    1987-01-01

    A sensor is described for detecting the difference in phase of a pair of returned light pulse components, such as the two components of a light pulse of an optical gyro. In an optic gyro, the two light components have passed in opposite directions through a coil of optical fiber, with the difference in phase of the returned light components determining the intensity of light shining on the sensor. The sensor includes a CCD (charge coupled device) that receives the pair of returned light components to generate a charge proportional to the number of photons in the received light. The amount of the charge represents the phase difference between the two light components. At a time after the transmission of the light pulse and before the expected time of arrival of the interfering light components, charge accumulating in the CCD as a result of reflections from optical components in the system, are repeatedly removed from the CCD, by transferring out charges in the CCD and dumping these charges.

  7. High-performance liquid chromatography with conductimetric detection of perfluorocarboxylic acids and perfluorosulfonates.

    PubMed

    Hori, Hisao; Hayakawa, Etsuko; Yamashita, Nobuyoshi; Taniyasu, Sachi; Nakata, Fumiya; Kobayashi, Yoshimi

    2004-10-01

    A rapid and simple method for separating and determining various environmentally harmful perfluorocarboxylic acids and perfluorosulfonates was successfully developed using high- performance liquid chromatography with conductimetric detection, for product and waste management of these compounds at manufacturing and processing sites. Compounds having C(3)-C(8) perfluoroalkyl groups were separated using a Tosoh TSKgel Super-ODS column and a mobile phase consisting of a mixture of methanol and aqueous NaH(2)PO(4) at several mixing ratios. The best detection limits for the compounds ranged from 0.12 to 0.66 mg l(-1) (ppm), and linear calibration graphs were obtained up to 87-109 mg l(-1). The combination of this method with concentration of the sample by solid-phase extraction with cartridges based on styrene-divinylbenzene-copolymer enabled the determination of approximately 50 microg l(-1) (ppb) for compounds with C(4)-C(8) perfluoroalkyl groups. This method was successfully used to monitor the artificial decomposition of the perfluorocarboxylic acid n-C(4)F(9)COOH induced by a photocatalyst. PMID:15312725

  8. Study on the spectrophotometric detection of free fatty acids in palm oil utilizing enzymatic reactions.

    PubMed

    Azeman, Nur Hidayah; Yusof, Nor Azah; Abdullah, Jaafar; Yunus, Robiah; Hamidon, Mohd Nizar; Hajian, Reza

    2015-01-01

    In this paper, a comprehensive study has been made on the detection of free fatty acids (FFAs) in palm oil via an optical technique based on enzymatic aminolysis reactions. FFAs in crude palm oil (CPO) were converted into fatty hydroxamic acids (FHAs) in a biphasic lipid/aqueous medium in the presence of immobilized lipase. The colored compound formed after complexation between FHA and vanadium (V) ion solution was proportional to the FFA content in the CPO samples and was analyzed using a spectrophotometric method. In order to develop a rapid detection system, the parameters involved in the aminolysis process were studied. The utilization of immobilized lipase as catalyst during the aminolysis process offers simplicity in the product isolation and the possibility of conducting the process under extreme reaction conditions. A good agreement was found between the developed method using immobilized Thermomyces lanuginose lipase as catalyst for the aminolysis process and the Malaysian Palm Oil Board (MPOB) standard titration method (R2 = 0.9453). PMID:26198220

  9. Method to attenuate U(VI) mobility in acidic waste plumes using humic acids.

    PubMed

    Wan, Jiamin; Dong, Wenming; Tokunaga, Tetsu K

    2011-03-15

    Acidic uranium (U) groundwater plumes have resulted from acid-extraction of plutonium during the Cold War and from U mining and milling operations. A sustainable method for in situ immobilization of U under acidic conditions is not yet available. Here, we propose to use humic acids (HAs) for in situ U immobilization in acidic waste plumes. Our laboratory batch experiments show that HA can adsorb onto aquifer sediments rapidly, strongly and practically irreversibly. Adding HA greatly enhanced U adsorption capacity to sediments at pH below 5.0. Our column experiments using historically contaminated sediments from the Savannah River Site under slow flow rates (120 and 12 m/year) show that desorption of U and HA were nondetectable over 100 pore-volumes of leaching with simulated acidic groundwaters. Upon HA-treatment, 99% of the contaminant [U] was immobilized at pH ≤ 4.5, compared to 5% and 58% immobilized in the control columns at pH 3.5 and 4.5, respectively. These results indicate that HA-treatment is a promising in situ remediation method for acidic U waste plumes. As a remediation reagent, HAs are resistant to biodegradation, cost-effective, nontoxic, and easily introducible to the subsurface. PMID:21319737

  10. Method for detecting trace impurities in gases

    DOEpatents

    Freund, Samuel M.; Maier, II, William B.; Holland, Redus F.; Beattie, Willard H.

    1981-01-01

    A technique for considerably improving the sensitivity and specificity of infrared spectrometry as applied to quantitative determination of trace impurities in various carrier or solvent gases is presented. A gas to be examined for impurities is liquefied and infrared absorption spectra of the liquid are obtained. Spectral simplification and number densities of impurities in the optical path are substantially higher than are obtainable in similar gas-phase analyses. Carbon dioxide impurity (.about.2 ppm) present in commercial Xe and ppm levels of Freon 12 and vinyl chloride added to liquefied air are used to illustrate the method.

  11. Method for detecting trace impurities in gases

    DOEpatents

    Freund, S.M.; Maier, W.B. II; Holland, R.F.; Beattie, W.H.

    A technique for considerably improving the sensitivity and specificity of infrared spectrometry as applied to quantitative determination of trace impurities in various carrier or solvent gases is presented. A gas to be examined for impurities is liquefied and infrared absorption spectra of the liquid are obtained. Spectral simplification and number densities of impurities in the optical path are substantially higher than are obtainable in similar gas-phase analyses. Carbon dioxide impurity (approx. 2 ppM) present in commercial Xe and ppM levels of Freon 12 and vinyl chloride added to liquefied air are used to illustrate the method.

  12. Simultaneous determination of lipoic acid (LA) and dihydrolipoic acid (DHLA) in human plasma using high-performance liquid chromatography coupled with electrochemical detection.

    PubMed

    Khan, Abad; Iqbal, Zafar; Watson, David G; Khan, Amirzada; Khan, Inamullah; Muhammad, Naveed; Muhammad, Salar; Nasib, Hashmat Ara; Iqbal, Naveed; Faiz-Ur-Rehman; Kashif, Muhammad

    2011-06-15

    A fast, simple, and a reliable high-performance liquid chromatography linked with electrochemical detector (HPLC-ECD) method for the assessment of lipoic acid (LA) and dihydrolipoic acid (DHLA) in plasma was developed using naproxen sodium as an internal standard (IS) and validated according to standard guidelines. Extraction of both analytes and IS from plasma (250 μl) was carried out with a single step liquid-liquid extraction applying dichloromethane. The separated organic layer was dried under stream of nitrogen at 40°C and the residue was reconstituted with the mobile phase. Complete separation of both compounds and IS at 30°C on Discovery HS C18 RP column (250 mm × 4.6 mm, 5 μm) was achieved in 9 min using acetonitrile: 0.05 M phosphate buffer (pH 2.4 adjusted with phosphoric acid) (52:48, v/v) as a mobile phase pumped at flow rate of 1.5 ml min(-1) using electrochemical detector in DC mode at the detector potential of 1.0 V. The limit of detection and limit of quantification for lipoic acid were 500 pg/ml and 3 ng/ml, and for dihydrolipoic acid were 3 ng/ml and 10 ng/ml, respectively. The absolute recoveries of lipoic acid and dihydrolipoic acid determined on three nominal concentrations were in the range of 93.40-97.06, and 93.00-97.10, respectively. Similarly coefficient of variations (% CV) for both intra-day and inter-day were between 0.829 and 3.097% for lipoic acid and between 1.620 and 5.681% for dihydrolipoic acid, respectively. This validated method was applied for the analysis of lipoic acid/dihydrolipoic acid in the plasma of human volunteers and will be used for the quantification of these compounds in patients with oxidative stress induced pathologies. PMID:21550862

  13. Wheat gluten amino acid analysis by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

    PubMed

    Rombouts, Ine; Lagrain, Bert; Lamberts, Lieve; Celus, Inge; Brijs, Kristof; Delcour, Jan A

    2012-01-01

    This chapter describes an accurate and user-friendly method for determining amino acid composition of wheat gluten proteins and their gliadin and glutenin fractions. The method consists of hydrolysis of the peptide bonds in 6.0 M hydrochloric acid solution at 110°C for 24 h, followed by evaporation of the acid and separation of the free amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection. In contrast to conventional methods, the analysis requires neither pre- or postcolumn derivatization, nor a time-consuming oxidation or derivatization step prior to hydrolysis. Correction factors account for incomplete release of Val and Ile even after hydrolysis for 24 h, and for losses of Ser during evaporation. Gradient conditions including an extra eluent allow multiple sequential sample analyses without risk of Glu accumulation on the anion-exchange column which otherwise would result from high Gln levels in gluten proteins. PMID:22125156

  14. Multicommutated stepwise injection determination of ascorbic acid in medicinal plants and food samples by capillary zone electrophoresis ultraviolet detection.

    PubMed

    Falkova, Marina T; Bulatov, Andrey V; Pushina, Maria O; Ekimov, Aleksey A; Alekseeva, Galina M; Moskvin, Leonid N

    2015-02-01

    An automation of the extraction of analytes from solid samples into the aqueous phase based on multicommutated stepwise injection analysis concept has been suggested. The feasibility of the approach has been demonstrated by determination of ascorbic acid as model analyte. The method includes automated extraction of ascorbic acid from solid sample into borate buffer solution pH 8 in mixing chamber during vigorous mixing by nitrogen stream, and subsequent detection by capillary zone electrophoresis at 254 nm. The method has a linear range of 0.1-5.0 mg g(-1) for ascorbic acid with the LOD of 0.03 mg g(-1). The sample throughput was 7 h(-1). This method was applied for determination of ascorbic acid in various medicinal plants and food samples. PMID:25435231

  15. A RAPID METHOD FOR THE EXTRACTION OF FUNGAL DNA FROM ENVIRONMENTAL SAMPLES: EVALUATION IN THE QUANTITATIVE ANALYSIS OF MEMNONIELLA ECHINATA CONIDIA USING REAL TIME DETECTION OF PCR PRODUCTS

    EPA Science Inventory

    New technologies are creating the potential for using nucleic acid sequence detection to perform routine microbiological analyses of environmental samples. Our laboratory has recently reported on the development of a method for the quantitative detection of Stachybotrys chartarum...

  16. Vapor generation methods for explosives detection research

    SciTech Connect

    Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

    2012-12-01

    The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

  17. Delamination detection using methods of computational intelligence

    NASA Astrophysics Data System (ADS)

    Ihesiulor, Obinna K.; Shankar, Krishna; Zhang, Zhifang; Ray, Tapabrata

    2012-11-01

    Abstract Reliable delamination prediction scheme is indispensable in order to prevent potential risks of catastrophic failures in composite structures. The existence of delaminations changes the vibration characteristics of composite laminates and hence such indicators can be used to quantify the health characteristics of laminates. An approach for online health monitoring of in-service composite laminates is presented in this paper that relies on methods based on computational intelligence. Typical changes in the observed vibration characteristics (i.e. change in natural frequencies) are considered as inputs to identify the existence, location and magnitude of delaminations. The performance of the proposed approach is demonstrated using numerical models of composite laminates. Since this identification problem essentially involves the solution of an optimization problem, the use of finite element (FE) methods as the underlying tool for analysis turns out to be computationally expensive. A surrogate assisted optimization approach is hence introduced to contain the computational time within affordable limits. An artificial neural network (ANN) model with Bayesian regularization is used as the underlying approximation scheme while an improved rate of convergence is achieved using a memetic algorithm. However, building of ANN surrogate models usually requires large training datasets. K-means clustering is effectively employed to reduce the size of datasets. ANN is also used via inverse modeling to determine the position, size and location of delaminations using changes in measured natural frequencies. The results clearly highlight the efficiency and the robustness of the approach.

  18. Capillary electrophoresis determination of glucosamine in nutraceutical formulations after labeling with anthranilic acid and UV detection.

    PubMed

    Volpi, Nicola

    2009-04-01

    A new robust CE method for the determination of the glucosamine (GlcN) content in nutraceutical formulations is described after its derivatization with anthranilic acid (2-aminobenzoic acid, AA). The CE separation of derivatized GlcN with AA was performed on an uncoated fused-silica capillary tube (50 microm I.D.) using an operating pH 7.0 buffer of 150 mM boric acid/50 mM NaH2PO4 and UV detection at 214 nm. The method was validated for specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). The detector response for GlcN was linear over the selected concentration range from 240 to 2400 pg (40-400 microg/mL) with a correlation coefficient greater than 0.980. The intra- and inter-day variations (CV%) were between 0.5 and 0.9 for migration time, and between 2.8 and 4.3 for peak area, respectively. The LOD and the LOQ of the method were approximately 200 and 500 pg, respectively. The intra- and inter-day accuracy was estimated to range from 2.8% to 5.1%, while the percent recoveries of GlcN in formulations were calculated to be about 100% after simple centrifugation for 10 min, lyophilization and derivatization with AA. The CE method was applied to the determination of GlcN content, in the form of GlcN-hydrochloride or GlcN-sulfate, of several nutraceutical preparations in the presence of other ingredients, i.e. chondroitin sulfate, vitamin C and/or methylsulfonylmethane (MSM) as well as salts and other agents. The quantitative results obtained were in total conformity with the label claims. PMID:19200685

  19. Nucleic acid based fluorescent sensor for mercury detection

    DOEpatents

    Lu, Yi; Liu, Juewen

    2013-02-05

    A nucleic acid enzyme comprises an oligonucleotide containing thymine bases. The nucleic acid enzyme is dependent on both Hg.sup.2+and a second ion as cofactors, to produce a product from a substrate. The substrate comprises a ribonucleotide, a deoxyribonucleotide, or both.

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

    PubMed

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

    2016-07-01

    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. PMID:25749054

  1. Preparation of κ-carra-oligosaccharides with microwave assisted acid hydrolysis method

    NASA Astrophysics Data System (ADS)

    Li, Guangsheng; Zhao, Xia; Lv, Youjing; Li, Miaomiao; Yu, Guangli

    2015-04-01

    A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization (DP) of oligosaccharides was detected by high performance thin layer chromatography (HPTLC) and polyacrylamide gel electrophoresis (PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg mL-1; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15 °C min. Oligosaccharides were separated by a Superdex 30 column (2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry (ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.

  2. Effects of Linking Methods on Detection of DIF.

    ERIC Educational Resources Information Center

    Kim, Seock-Ho; Cohen, Allan S.

    1992-01-01

    Effects of the following methods for linking metrics on detection of differential item functioning (DIF) were compared: (1) test characteristic curve method (TCC); (2) weighted mean and sigma method; and (3) minimum chi-square method. With large samples, results were essentially the same. With small samples, TCC was most accurate. (SLD)

  3. Method and apparatus for detecting chemical binding

    DOEpatents

    Warner, Benjamin P.; Havrilla, George J.; Miller, Thomasin C.; Wells, Cyndi A.

    2007-07-10

    The method for screening binding between a target binder and potential pharmaceutical chemicals involves sending a solution (preferably an aqueous solution) of the target binder through a conduit to a size exclusion filter, the target binder being too large to pass through the size exclusion filter, and then sending a solution of one or more potential pharmaceutical chemicals (preferably an aqueous solution) through the same conduit to the size exclusion filter after target binder has collected on the filter. The potential pharmaceutical chemicals are small enough to pass through the filter. Afterwards, x-rays are sent from an x-ray source to the size exclusion filter, and if the potential pharmaceutical chemicals form a complex with the target binder, the complex produces an x-ray fluorescence signal having an intensity that indicates that a complex has formed.

  4. Method And Apparatus For Detecting Chemical Binding

    DOEpatents

    Warner, Benjamin P.; Havrilla, George J.; Miller, Thomasin C.; Wells, Cyndi A.

    2005-02-22

    The method for screening binding between a target binder and potential pharmaceutical chemicals involves sending a solution (preferably an aqueous solution) of the target binder through a conduit to a size exclusion filter, the target binder being too large to pass through the size exclusion filter, and then sending a solution of one or more potential pharmaceutical chemicals (preferably an aqueous solution) through the same conduit to the size exclusion filter after target binder has collected on the filter. The potential pharmaceutical chemicals are small enough to pass through the filter. Afterwards, x-rays are sent from an x-ray source to the size exclusion filter, and if the potential pharmaceutical chemicals form a complex with the target binder, the complex produces an x-ray fluorescence signal having an intensity that indicates that a complex has formed.

  5. Comparative assessment of the methods for exchangeable acidity measuring

    NASA Astrophysics Data System (ADS)

    Vanchikova, E. V.; Shamrikova, E. V.; Bespyatykh, N. V.; Zaboeva, G. A.; Bobrova, Yu. I.; Kyz"yurova, E. V.; Grishchenko, N. V.

    2016-05-01

    A comparative assessment of the results of measuring the exchangeable acidity and its components by different methods was performed for the main mineral genetic horizons of texturally-differentiated gleyed and nongleyed soddy-podzolic and gley-podzolic soils of the Komi Republic. It was shown that the contents of all the components of exchangeable soil acidity determined by the Russian method (with potassium chloride solution as extractant, c(KCl) = 1 mol/dm3) were significantly higher than those obtained by the international method (with barium chloride solution as extractant, c(BaCl2) = 0.1 mol/dm3). The error of the estimate of the concentration of H+ ions extracted with barium chloride solution equaled 100%, and this allowed only qualitative description of this component of the soil acidity. In the case of the extraction with potassium chloride, the error of measurements was 50%. It was also shown that the use of potentiometric titration suggested by the Russian method overestimates the results of soil acidity measurement caused by the exchangeable metal ions (Al(III), Fe(III), and Mn(II)) in comparison with the atomic emission method.

  6. Cationic poly(lactic-co-glycolic acid) iron oxide microspheres for nucleic acid detection

    NASA Astrophysics Data System (ADS)

    Pandey, Chandra Mouli; Sharma, Aditya; Sumana, Gajjala; Tiwari, Ida; Malhotra, Bansi Dhar

    2013-04-01

    Herein, we envisage the possibility of preparing stable cationic poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating the iron oxide nanoparticles (IONPs; 8-12 nm). The IONPs are incorporated into PLGA in organic phase followed by microsphere formation and chitosan coating in aqueous medium via nano-emulsion technique. The average size of the microspheres, as determined by dynamic light scattering are about 310 nm, while the zeta potential for the composite remains near 35 mV at pH 4.0. These microspheres are electrophoretically deposited onto indium tin oxide (ITO)-coated glass substrate used as cathode and parallel platinum plate as the counter electrode. This platform is utilized to fabricate a DNA biosensor, by immobilizing a probe sequence specific to Escherichia coli. The bioelectrode shows a surface-controlled electrode reaction with the electron transfer coefficient (α) of 0.64 and charge transfer rate constant (ks) of 61.73 s-1. Under the optimal conditions, this biosensor shows a detection limit of 8.7 × 10-14 M and is found to retain about 81% of the initial activity after 9 cycles of use.Herein, we envisage the possibility of preparing stable cationic poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating the iron oxide nanoparticles (IONPs; 8-12 nm). The IONPs are incorporated into PLGA in organic phase followed by microsphere formation and chitosan coating in aqueous medium via nano-emulsion technique. The average size of the microspheres, as determined by dynamic light scattering are about 310 nm, while the zeta potential for the composite remains near 35 mV at pH 4.0. These microspheres are electrophoretically deposited onto indium tin oxide (ITO)-coated glass substrate used as cathode and parallel platinum plate as the counter electrode. This platform is utilized to fabricate a DNA biosensor, by immobilizing a probe sequence specific to Escherichia coli. The bioelectrode shows a surface-controlled electrode reaction with the

  7. Harmonic Motion Microwave Doppler Imaging method for breast tumor detection.

    PubMed

    Top, Can Barıs; Tafreshi, Azadeh Kamali; Gençer, Nevzat G

    2014-01-01

    Harmonic Motion Microwave Doppler Imaging (HMMDI) method is recently proposed as a non-invasive hybrid breast imaging technique for tumor detection. The acquired data depend on acoustic, elastic and electromagnetic properties of the tissue. The potential of the method is analyzed with simulation studies and phantom experiments. In this paper, the results of these studies are summarized. It is shown that HMMDI method has a potential to detect malignancies inside fibro-glandular tissue. PMID:25571382

  8. Preparation of a novel colorimetric luminescence sensor strip for the detection of indole-3-acetic acid.

    PubMed

    Liu, Yan; Dong, Haitao; Zhang, Wenzhu; Ye, Zhiqiang; Wang, Guilan; Yuan, Jingli

    2010-06-15

    A novel colorimetric luminescence sensor strip for the detection of indole-3-acetic acid (IAA) has been fabricated by using green emissive quantum dots of cadmium telluride (CdTe QDs) as a background layer and a red emissive europium chelate, [4'-(9-anthryl)-2,2':6',2''-terpyridine-6,6''-diyl]bis(methylenenitrilo) tetrakis(acetate)-Eu(3+) (ATTA-Eu(3+)), as a specific sensing layer coated on the surface of glass slide, respectively. The luminescence response of the sensor strip is given by the dramatic changes in emission colors from green to red at different IAA concentrations. This approach provides a simple, rapid, sensitive and accurate method for the detection of IAA without using any special scientific instruments. PMID:20353890

  9. Determination of kynurenic acid in rat cerebrospinal fluid by HPLC with fluorescence detection.

    PubMed

    Bao, Ye; Luchetti, David; Schaeffer, Eric; Cutrone, Jingfang

    2016-01-01

    A sensitive HPLC method using fluorescence detection was developed to determine kynurenic acid (KYNA) level in rat cerebrospinal fluid (CSF). The method development was accomplished by screening different columns, optimizing zinc acetate concentration and determining the optimal HPLC flow rate. This method allowed direct injection of the CSF samples onto an Xselect C18 column and KYNA levels were measured fluorometrically by forming a fluorescent complex with zinc acetate that was delivered post-column. The limit of quantitation was 0.2 n m with 30 μL injection, corresponding to 6 fmol (signal-to-noise ratio = 10). The improved sensitivity enabled the measurement of KYNA in naive and drug-treated rat CSF. PMID:25963282

  10. 25 Years of Self-organized Criticality: Numerical Detection Methods

    NASA Astrophysics Data System (ADS)

    McAteer, R. T. James; Aschwanden, Markus J.; Dimitropoulou, Michaila; Georgoulis, Manolis K.; Pruessner, Gunnar; Morales, Laura; Ireland, Jack; Abramenko, Valentyna

    2016-01-01

    The detection and characterization of self-organized criticality (SOC), in both real and simulated data, has undergone many significant revisions over the past 25 years. The explosive advances in the many numerical methods available for detecting, discriminating, and ultimately testing, SOC have played a critical role in developing our understanding of how systems experience and exhibit SOC. In this article, methods of detecting SOC are reviewed; from correlations to complexity to critical quantities. A description of the basic autocorrelation method leads into a detailed analysis of application-oriented methods developed in the last 25 years. In the second half of this manuscript space-based, time-based and spatial-temporal methods are reviewed and the prevalence of power laws in nature is described, with an emphasis on event detection and characterization. The search for numerical methods to clearly and unambiguously detect SOC in data often leads us outside the comfort zone of our own disciplines—the answers to these questions are often obtained by studying the advances made in other fields of study. In addition, numerical detection methods often provide the optimum link between simulations and experiments in scientific research. We seek to explore this boundary where the rubber meets the road, to review this expanding field of research of numerical detection of SOC systems over the past 25 years, and to iterate forwards so as to provide some foresight and guidance into developing breakthroughs in this subject over the next quarter of a century.

  11. A novel method for determining target detection thresholds

    NASA Astrophysics Data System (ADS)

    Grossman, S.

    2015-05-01

    Target detection is the act of isolating objects of interest from the surrounding clutter, generally using some form of test to include objects in the found class. However, the method of determining the threshold is overlooked relying on manual determination either through empirical observation or guesswork. The question remains: how does an analyst identify the detection threshold that will produce the optimum results? This work proposes the concept of a target detection sweet spot where the missed detection probability curve crosses the false detection curve; this represents the point at which missed detects are traded for false detects in order to effect positive or negative changes in the detection probability. ROC curves are used to characterize detection probabilities and false alarm rates based on empirically derived data. It identifies the relationship between the empirically derived results and the first moment statistic of the histogram of the pixel target value data and then proposes a new method of applying the histogram results in an automated fashion to predict the target detection sweet spot at which to begin automated target detection.

  12. Method for preparing 6-.beta.-halopenicillanic acids

    DOEpatents

    Hansen, Erik I.; Kran-Nielsen, Mogens P.; Von Daehne, Welf

    1989-01-01

    The present invention relates to a new and improved method for the preparation of a compound of the formula I ##STR1## in which R stands for halogen, giving rise to high yields of substantially pure 6.beta.-halopenicillanic acids, obtained in one step.

  13. [Advance in detection methods of microbes on historic stones--a review].

    PubMed

    Yu, Miao; Zhu, Xudong; Pan, Jiao

    2011-11-01

    We reviewed the methods for identification of microorganisms on the surface of historic stones, including nucleic acid analysis, cell membrane analysis, secondary metabolites analysis and the traditional culture analysis. After comprehensive comparison of the advantages and disadvantages of each method, we addressed the biological protection of stone artifacts. The establishment of rapid detection of microorganisms on the historic stones is important to prevent corrosion caused by microorganisms and to protect our valuable cultural heritage. PMID:22260041

  14. Microwave-accelerated method for ultra-rapid extraction of Neisseria gonorrhoeae DNA for downstream detection.

    PubMed

    Melendez, Johan H; Santaus, Tonya M; Brinsley, Gregory; Kiang, Daniel; Mali, Buddha; Hardick, Justin; Gaydos, Charlotte A; Geddes, Chris D

    2016-10-01

    Nucleic acid-based detection of gonorrhea infections typically require a two-step process involving isolation of the nucleic acid, followed by detection of the genomic target often involving polymerase chain reaction (PCR)-based approaches. In an effort to improve on current detection approaches, we have developed a unique two-step microwave-accelerated approach for rapid extraction and detection of Neisseria gonorrhoeae (gonorrhea, GC) DNA. Our approach is based on the use of highly focused microwave radiation to rapidly lyse bacterial cells, release, and subsequently fragment microbial DNA. The DNA target is then detected by a process known as microwave-accelerated metal-enhanced fluorescence (MAMEF), an ultra-sensitive direct DNA detection analytical technique. In the current study, we show that highly focused microwaves at 2.45 GHz, using 12.3-mm gold film equilateral triangles, are able to rapidly lyse both bacteria cells and fragment DNA in a time- and microwave power-dependent manner. Detection of the extracted DNA can be performed by MAMEF, without the need for DNA amplification, in less than 10 min total time or by other PCR-based approaches. Collectively, the use of a microwave-accelerated method for the release and detection of DNA represents a significant step forward toward the development of a point-of-care (POC) platform for detection of gonorrhea infections. PMID:27325503

  15. Electronic detection of target nucleic acids by a 2,6-disulfonic acid anthraquinone intercalator.

    PubMed

    Wong, Elicia L S; Gooding, J Justin

    2003-08-01

    A DNA hybridization biosensor based on long-range electron transfer that is capable of detecting DNA single-base mismatch is presented. A mixed self-assembled monolayer of single-stranded DNA (ss-DNA), thiolated at the 3' end, and 6-mercapto-1-hexanol was formed on a gold surface. This probe ss-DNA-modified gold surface was incubated in 2,6-disulfonic acid anthraquinone (AQDS) intercalator solution, rinsed, and placed in an AQDS-free buffer solution, whereupon voltammetric experiments were performed. No voltammetric peaks were observed for probe ss-DNA-modified gold electrodes. Upon DNA hybridization and incubation in AQDS, clear voltammetric peaks, consistent with the oxidation and reduction of AQDS, were observed. The absence of AQDS electrochemistry for ss-DNA-modified surfaces clearly shows the electrochemistry is due to long-range electron transfer through the DNA duplex. No peak currents were observed when the probe ss-DNA-modified surface was exposed to noncomplementary target DNA, but there was a diminution in current signal upon hybridization with C-A mismatched and a G-A mismatched targets. PMID:14572052

  16. Enhanced Sensitivity for Hydrogen Peroxide Detection: Polydiacetylene Vesicles with Phenylboronic Acid Head Group.

    PubMed

    Jia, Chen; Tang, Jie; Lu, Shengguo; Han, Yuwang; Huang, He

    2016-01-01

    It was recently reported that, besides UV irradiated polymerization, polymerization of diacetylene compounds could also been initiated by radicals generated from enzyme catalyzed hydrogen peroxide (H2O2) decomposition. A new optical sensing method for H2O2 was proposed based on this phenomenon. However, the sensitivity of this method is relatively lower than existed ones. In the present work, phenylboronic acid (PBA) functionalized 10, 12-pentacosadiynoic acid (PDA-PBA) was synthesized and its vesicles were formed successfully as colorimetric sensor for H2O2 detection. It was found that color change during the polymerization of vesicles composed of the PBA modified monomer is much stronger than that of the non-modified one. The response of PDA-PBA vesicles to H2O2 is 16 times more sensitive than that of the PDA. The absorption of PDA-PBA at 650 nm is linearly related to the concentration of H2O2 and a detection limit of ~5 μM could be achieved. PMID:26511954

  17. Sonoclot(®)-based method to detect iron enhanced coagulation.

    PubMed

    Nielsen, Vance G; Henderson, Jon

    2016-07-01

    Thrombelastographic methods have been recently introduced to detect iron mediated hypercoagulability in settings such as sickle cell disease, hemodialysis, mechanical circulatory support, and neuroinflammation. However, these inflammatory situations may have heme oxygenase-derived, coexistent carbon monoxide present, which also enhances coagulation as assessed by the same thrombelastographic variables that are affected by iron. This brief report presents a novel, Sonoclot-based method to detect iron enhanced coagulation that is independent of carbon monoxide influence. Future investigation will be required to assess the sensitivity of this new method to detect iron mediated hypercoagulability in clinical settings compared to results obtained with thrombelastographic techniques. PMID:26497986

  18. Systems and methods for detection of blowout precursors in combustors

    DOEpatents

    Lieuwen, Tim C.; Nair, Suraj

    2006-08-15

    The present invention comprises systems and methods for detecting flame blowout precursors in combustors. The blowout precursor detection system comprises a combustor, a pressure measuring device, and blowout precursor detection unit. A combustion controller may also be used to control combustor parameters. The methods of the present invention comprise receiving pressure data measured by an acoustic pressure measuring device, performing one or a combination of spectral analysis, statistical analysis, and wavelet analysis on received pressure data, and determining the existence of a blowout precursor based on such analyses. The spectral analysis, statistical analysis, and wavelet analysis further comprise their respective sub-methods to determine the existence of blowout precursors.

  19. Chromatographic method for determination of the free amino acid content of chamomile flowers

    PubMed Central

    Ma, Xiaoli; Zhao, Dongsheng; Li, Xinxia; Meng, Lei

    2015-01-01

    Objective: To determine the free amino acid contents of chamomile flowers using reverse-phase high-performance column chromatography preceded by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), and to determine the reliability of this method. Materials and Methods: Derivatization with reconstituted AQC was used to prepare the samples and standards for injection into the chromatography column. The peaks were analyzed by fluorescence detection (λ excitation, 250 nm; λ emission, 395 nm. Results: Alanine, proline, and leucine were the most abundant amino acids, whereas tyrosine and methionine were the least abundant. The linearity of the method was found to be good with amino acid concentrations of 0.012-0.36 μM. The precision was 0.05-1.36%; average recovery, 91.12-129.41%; and limit of detection, 0.006-0.058 μM. Conclusion: The method is reliable for determining the free amino acid content of different types of chamomile flowers. PMID:25709230

  20. Rapid method for glutathione quantitation using high-performance liquid chromatography with coulometric electrochemical detection.

    PubMed

    Bayram, Banu; Rimbach, Gerald; Frank, Jan; Esatbeyoglu, Tuba

    2014-01-15

    A rapid, sensitive, and direct method (without derivatization) was developed for the detection of reduced glutathione (GSH) in cultured hepatocytes (HepG2 cells) using high-performance liquid chromatography with electrochemical detection (HPLC-ECD). The method was validated according to the guidelines of the U.S. Food and Drug Administration in terms of linearity, lower limit of quantitation (LOQ), lower limit of detection (LOD), precision, accuracy, recovery, and stabilities of GSH standards and quality control samples. The total analysis time was 5 min, and the retention time of GSH was 1.78 min. Separation was carried out isocratically using 50 mM sodium phosphate (pH 3.0) as a mobile phase with a fused-core column. The detector response was linear between 0.01 and 80 μmol/L, and the regression coefficient (R(2)) was >0.99. The LOD for GSH was 15 fmol, and the intra- and interday recoveries ranged between 100.7 and 104.6%. This method also enabled the rapid detection (in 4 min) of other compounds involved in GSH metabolism such as uric acid, ascorbic acid, and glutathione disulfite. The optimized and validated HPLC-ECD method was successfully applied for the determination of GSH levels in HepG2 cells treated with buthionine sulfoximine (BSO), an inhibitor, and α-lipoic acid (α-LA), an inducer of GSH synthesis. As expected, the amount of GSH concentration-dependently decreased with BSO and increased with α-LA treatments in HepG2 cells. This method could also be useful for the quantitation of GSH, uric acid, ascorbic acid, and glutathione disulfide in other biological matrices such as tissue homogenates and blood. PMID:24328299

  1. Spectrophotometric methods for the evaluation of acidity constants-I Numerical methods for single equilibria.

    PubMed

    Asuero, A G; Navas, M J; Jiminez-Trillo, J L

    1986-02-01

    The spectrophotometric methods applicable to the numerical evaluation of acidity constants of monobasic acids are briefly reviewed. The equations are presented in a form suitable for easy calculation with a programmable pocket calculator. The aim of this paper is to cover a gap in the education analytical literature. PMID:18964064

  2. Cognitive radio: methods for the detection of free bands

    NASA Astrophysics Data System (ADS)

    Ghozzi, Mohamed; Dohler, Mischa; Marx, François; Palicot, Jacques

    2006-09-01

    In contrast to current systems where the spectrum allocation is static, future cognitive radio devices will be able to seek and use in a dynamic way the frequencies for network access; this will be done by autonomous detection of vacant bands in the radio spectrum. In this article, we are interested in various methods of detection of a signal embedded in the noise by specifying their advantages and their drawbacks. Following that, a cyclostationary detection method, called multi-cycles detection, will be proposed. For illustrative purposes, we will apply these methods to the detection of the free channels within the television (TV) bands. To cite this article: M. Ghozzi et al., C. R. Physique 7 (2006).

  3. Capillary electrophoresis based on nucleic acid detection for diagnosing human infectious disease.

    PubMed

    Lian, Dong-Sheng; Zhao, Shu-Jin

    2016-05-01

    Rapid transmission, high morbidity, and mortality are the features of human infectious diseases caused by microorganisms, such as bacteria, fungi, and viruses. These diseases may lead within a short period of time to great personal and property losses, especially in regions where sanitation is poor. Thus, rapid diagnoses are vital for the prevention and therapeutic intervention of human infectious diseases. Several conventional methods are often used to diagnose infectious diseases, e.g. methods based on cultures or morphology, or biochemical tests based on metabonomics. Although traditional methods are considered gold standards and are used most frequently, they are laborious, time consuming, and tedious and cannot meet the demand for rapid diagnoses. Disease diagnosis using capillary electrophoresis methods has the advantages of high efficiency, high throughput, and high speed, and coupled with the different nucleic acid detection strategies overcomes the drawbacks of traditional identification methods, precluding many types of false positive and negative results. Therefore, this review focuses on the application of capillary electrophoresis based on nucleic detection to the diagnosis of human infectious diseases, and offers an introduction to the limitations, advantages, and future developments of this approach. PMID:26352354

  4. Spectrophotometric method for fast quantification of ascorbic acid and dehydroascorbic acid in simple matrix for kinetics measurements.

    PubMed

    Gómez Ruiz, Braulio; Roux, Stéphanie; Courtois, Francis; Bonazzi, Catherine

    2016-11-15

    A simple, rapid and reliable method was developed for quantifying ascorbic (AA) and dehydroascorbic (DHAA) acids and validated in 20mM malate buffer (pH 3.8). It consists in a spectrophotometric measurement of AA, either directly on the solution added with metaphosphoric acid or after reduction of DHAA into AA by dithiothreitol. This method was developed with real time measurement of reactions kinetics in bulk reactors in mind, and was checked in terms of linearity, limits of detection and quantification, fidelity and accuracy. The linearity was found satisfactory on the range of 0-6.95mM with limits of detection and quantification of 0.236mM and 0.467mM, respectively. The method was found acceptable in terms of fidelity and accuracy with a coefficient of variation for repeatability and reproducibility below 6% for AA and below 15% for DHAA, and with a recovery range of 97-102% for AA and 88-112% for DHAA. PMID:27283671

  5. Fluorescent carbon nanodots for sensitive and selective detection of tannic acid in wines.

    PubMed

    Ahmed, Gaber Hashem Gaber; Laíño, Rosana Badía; Calzón, Josefa Angela García; García, Marta Elena Díaz

    2015-01-01

    Herein we describe an easy one step synthesis of carbon nanodots (C-dots) by thermal carbonization of 6-bromohexylboronic acid using two different amine compounds, polyethyleneglycol bis(3-aminopropyl (PEGA) and 1,2-aminopropane (DPA), at 180 °C in atmospheric oxygen. The as-synthesized C-dots were characterized by FTIR, HRTEM, NMR and fluorescence. The C-dots prepared using PEGA showed a strong emission at 440 nm with excitation at 362 nm. These C-dots exhibited analytical potential as sensing probes for tannic acid (TA) determination. pH effect, interferences, and analytical performance of the method were investigated. The method was found effective in the linear concentration range from 0.1 to 10 mg L(-1) TA achieving a limit of detection equal 0.018 mg L(-1) TA. The applicability of the method was demonstrated by direct measurements of TA in red and white wine samples. Validation of the method was achieved by spiking the wine samples with different standard TA concentrations obtaining recoveries in the range (90-112.5%). A probable mechanism by which TA quenched the C-dots fluorescence was proposed. PMID:25476306

  6. AquaLite, a bioluminescent label for immunoassay and nucleic acid detection: quantitative analyses at the attomol level

    NASA Astrophysics Data System (ADS)

    Smith, David F.; Stults, Nancy L.

    1996-04-01

    AquaLiteR is a direct, bioluminescent label capable of detecting attomol levels of analyte in clinical immunoassays and assays for the quantitative measurement of nucleic acids. Bioluminescent immunoassays (BIAs) require no radioisotopes and avoid complex fluorescent measurements and many of the variables of indirect enzyme immunoassays (EIAs). AquaLite, a recombinant form of the photoprotein aequorin from a bioluminescent jellyfish, is coupled directly to antibodies to prepare bioluminescent conjugates for assay development. When the AquaLite-antibody complex is exposed to a solution containing calcium ions, a flash of blue light ((lambda) max equals 469 nm) is generated. The light signal is measured in commercially available luminometers that simultaneously inject a calcium solution and detect subattomol photoprotein levies in either test tubes or microtiter plates. Immunometric or 'sandwich' type assays are available for the quantitative measurement of human endocrine hormones and nucleic acids. The AquaLite TSH assay can detect 1 attomol of thyroid stimulating hormone (TSH) in 0.2 mL of human serum and is a useful clinical tool for diagnosing hyperthyroid patients. AquaLite-based nucleic acid detection permits quantifying attomol levels of specific nucleic acid markers and represents possible solution to the difficult problem of quantifying the targets of nucleic acid amplification methods.

  7. Can Molecular Methods Detect 1% Isoniazid Resistance in Mycobacterium tuberculosis?

    PubMed Central

    Folkvardsen, Dorte Bek; Thomsen, Vibeke Ø.; Rasmussen, Erik Michael; Bang, Didi; Werngren, Jim; Hoffner, Sven; Hillemann, Doris; Rigouts, Leen

    2013-01-01

    Patients may harbor both drug-susceptible and -resistant bacteria, representing heteroresistance. We studied mixtures of isoniazid-resistant and -susceptible Mycobacterium tuberculosis strains. Conventional drug susceptibility testing was the most sensitive method of detection, whereas the line probe assay and sequencing were not able to detect the clinically relevant 1% proportion of resistant bacteria. PMID:23447641

  8. Method for the detection of Salmonella enterica serovar Enteritidis

    DOEpatents

    Agron, Peter G.; Andersen, Gary L.; Walker, Richard L.

    2008-10-28

    Described herein is the identification of a novel Salmonella enterica serovar Enteritidis locus that serves as a marker for DNA-based identification of this bacterium. In addition, three primer pairs derived from this locus that may be used in a nucleotide detection method to detect the presence of the bacterium are also disclosed herein.

  9. Method of enhancing radiation response of radiation detection materials

    DOEpatents

    Miller, Steven D.

    1997-01-01

    The present invention is a method of increasing radiation response of a radiation detection material for a given radiation signal by first pressurizing the radiation detection material. Pressurization may be accomplished by any means including mechanical and/or hydraulic. In this application, the term "pressure" includes fluid pressure and/or mechanical stress.

  10. A Comparative Study of Recently Proposed Item Bias Detection Methods.

    ERIC Educational Resources Information Center

    Seong, Tae-Je; Subkoviak, Michael J.

    The purpose of this research was to reinvestigate the accuracy of three item bias detection procedures: (1) Linn and Harnisch's pseudo-IRT(Z) method; (2) Camilli's chi-square technique; and (3) Angoff's revised transformed item difficulty method. These methods are applied when the minority group sample size is too small to obtain stable estimates…

  11. Detection of non-protein amino acids in the presence of protein amino acids. II.

    NASA Technical Reports Server (NTRS)

    Shapshak, P.; Okaji, M.

    1972-01-01

    Studies conducted with the JEOL 5AH amino acid analyzer are described. This instrument makes possible the programming of the chromatographic process. Data are presented showing the separations of seventeen non-protein amino acids in the presence of eighteen protein amino acids. It is pointed out that distinct separations could be obtained in the case of a number of chemically similar compounds, such as ornithine and lysine, N-amidino alanine and arginine, and iminodiacetic acid and S-carboxymethyl cysteine and aspartic acid.

  12. A validated method for gas chromatographic analysis of gamma-aminobutyric acid in tall fescue herbage.

    PubMed

    Kagan, Isabelle A; Coe, Brenda L; Smith, Lori L; Huo, Cheng-Jun; Dougherty, Charles T; Strickland, James R

    2008-07-23

    Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in animals that is also found in plants and has been associated with plant responses to stress. A simple and relatively rapid method of GABA separation and quantification was developed from a commercially available kit for serum amino acids (Phenomenex EZ:faast) and validated for tall fescue (Festuca arundinacea). Extraction in ethanol/water (80:20, v/v) at ambient temperature yielded detectable amounts of GABA. Clean separation from other amino acids in 28 min was achieved by gas chromatography (GC) with flame ionization detection (FID), using a 30 m, 5% phenyl/95% dimethylpolysiloxane column. The identity of the putative GABA peak was confirmed by GC with mass spectrometric (MS) detection. The relatively small effects of the sample matrix on GABA measurement were verified by demonstrating slope parallelism of GABA curves prepared in the presence and absence of fescue extracts. Limits of quantification and detection were 2.00 and 1.00 nmol/100 microL, respectively. Method recoveries at two different spike levels were 96.4 and 94.2%, with coefficients of variation of 7.3 and 7.2%, respectively. PMID:18558696

  13. Qualitative analysis of some carboxylic acids by ion-exclusion chromatography with atmospheric pressure chemical ionization mass spectrometric detection.

    PubMed

    Helale, Murad I H; Tanaka, Kazuhiko; Taoda, Hiroshi; Hu, Wenzhi; Hasebe, Kiyoshi; Haddad, Paul R

    2002-05-17

    A simple, selective and sensitive method for the determination of carboxylic acids has been developed. A mixture of formic, acetic, propionic, valeric, isovaleric, isobutyric, and isocaproic acids has been separated on a polymethacrylate-based weak acidic cation-exchange resin (TSK gel OA pak-A) based on an ion-exclusion chromatographic mechanism with detection using UV-photodiode array, conductivity and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). A mobile phase consisting of 0.85 mM benzoic acid in 10% aqueous methanol (pH 3.89) was used to separate the above carboxylic acids in about 40 min. For LC-MS, the APCI interface was used in the negative ionization mode. Linear plots of peak area versus concentration were obtained over the range 1-30 mM (r2=0.9982) and 1-30 mM (r2=0.9958) for conductimetric and MS detection, respectively. The detection limits of the target carboxylic acids calculated at S/N=3 ranged from 0.078 to 2.3 microM for conductimetric and photometric detection and from 0.66 to 3.82 microM for ion-exclusion chromatography-APCI-MS. The reproducibility of retention times was 0.12-0.16% relative standard deviation for ion-exclusion chromatography and 1.21-2.5% for ion-exclusion chromatography-APCI-MS. The method was applied to the determination of carboxylic acids in red wine, white wine, apple vinegar, and Japanese rice wine. PMID:12108651

  14. A fast automatic target detection method for detecting ships in infrared scenes

    NASA Astrophysics Data System (ADS)

    Özertem, Kemal Arda

    2016-05-01

    Automatic target detection in infrared scenes is a vital task for many application areas like defense, security and border surveillance. For anti-ship missiles, having a fast and robust ship detection algorithm is crucial for overall system performance. In this paper, a straight-forward yet effective ship detection method for infrared scenes is introduced. First, morphological grayscale reconstruction is applied to the input image, followed by an automatic thresholding onto the suppressed image. For the segmentation step, connected component analysis is employed to obtain target candidate regions. At this point, it can be realized that the detection is defenseless to outliers like small objects with relatively high intensity values or the clouds. To deal with this drawback, a post-processing stage is introduced. For the post-processing stage, two different methods are used. First, noisy detection results are rejected with respect to target size. Second, the waterline is detected by using Hough transform and the detection results that are located above the waterline with a small margin are rejected. After post-processing stage, there are still undesired holes remaining, which cause to detect one object as multi objects or not to detect an object as a whole. To improve the detection performance, another automatic thresholding is implemented only to target candidate regions. Finally, two detection results are fused and post-processing stage is repeated to obtain final detection result. The performance of overall methodology is tested with real world infrared test data.

  15. Ultra-sensitive detection of zinc oxide nanowires using a quartz crystal microbalance and phosphoric acid DNA

    NASA Astrophysics Data System (ADS)

    Jang, Kuewhan; You, Juneseok; Park, Chanhoo; Park, Hyunjun; Choi, Jaeyeong; Choi, Chang-Hwan; Park, Jinsung; Lee, Howon; Na, Sungsoo

    2016-09-01

    Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, in situ detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10‑4 μg ml‑1 in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the ‘real-world’ environment.

  16. Ultra-sensitive detection of zinc oxide nanowires using a quartz crystal microbalance and phosphoric acid DNA.

    PubMed

    Jang, Kuewhan; You, Juneseok; Park, Chanhoo; Park, Hyunjun; Choi, Jaeyeong; Choi, Chang-Hwan; Park, Jinsung; Lee, Howon; Na, Sungsoo

    2016-09-01

    Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, in situ detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10(-4) μg ml(-1) in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the 'real-world' environment. PMID:27479871

  17. Method comparison study for weak acid dissociation cyanide analysis.

    PubMed

    Evans, Joseph D; Thompson, Leslie; Clark, Patrick J; Beckman, Scott W

    2003-02-01

    Method comparison studies of two different methods for the analysis of weak acid dissociable (WAD) cyanide revealed analytical flaws and/or matrix interference problems with both procedures. EPA "draft" method 1677 using a Perstorp 3202 CN analyzer was compared to Standard Method 4500 CN I. It was discovered that the Perstorp analyzer produced more precise and more accurate results once appropriate and necessary procedural steps from the EPA draft method were modified. Comparison of these two methods, was based on "real world" samples collected from a mine-tailing solution. The mine-tailing solution contained high concentrations of cyanide and metals. Inconsistencies in method procedures were traced to sulfide interferences and high concentrations of WAD metals. Conclusions were based upon a large sample base collected from a mine site over a 90-day period. PMID:12630477

  18. Nested methylation-specific polymerase chain reaction cancer detection method

    DOEpatents

    Belinsky, Steven A.; Palmisano, William A.

    2007-05-08

    A molecular marker-based method for monitoring and detecting cancer in humans. Aberrant methylation of gene promoters is a marker for cancer risk in humans. A two-stage, or "nested" polymerase chain reaction method is disclosed for detecting methylated DNA sequences at sufficiently high levels of sensitivity to permit cancer screening in biological fluid samples, such as sputum, obtained non-invasively. The method is for detecting the aberrant methylation of the p16 gene, O 6-methylguanine-DNA methyltransferase gene, Death-associated protein kinase gene, RAS-associated family 1 gene, or other gene promoters. The method offers a potentially powerful approach to population-based screening for the detection of lung and other cancers.

  19. [Fast Implementation Method of Protein Spots Detection Based on CUDA].

    PubMed

    Xiong, Bangshu; Ye, Yijia; Ou, Qiaofeng; Zhang, Haodong

    2016-02-01

    In order to improve the efficiency of protein spots detection, a fast detection method based on CUDA was proposed. Firstly, the parallel algorithms of the three most time-consuming parts in the protein spots detection algorithm: image preprocessing, coarse protein point detection and overlapping point segmentation were studied. Then, according to single instruction multiple threads executive model of CUDA to adopted data space strategy of separating two-dimensional (2D) images into blocks, various optimizing measures such as shared memory and 2D texture memory are adopted in this study. The results show that the operative efficiency of this method is obviously improved compared to CPU calculation. As the image size increased, this method makes more improvement in efficiency, such as for the image with the size of 2,048 x 2,048, the method of CPU needs 52,641 ms, but the GPU needs only 4,384 ms. PMID:27382745

  20. Passive background correction method for spatially resolved detection

    DOEpatents

    Schmitt, Randal L.; Hargis, Jr., Philip J.

    2011-05-10

    A method for passive background correction during spatially or angularly resolved detection of emission that is based on the simultaneous acquisition of both the passive background spectrum and the spectrum of the target of interest.

  1. An improved PCA method with application to boiler leak detection.

    PubMed

    Sun, Xi; Marquez, Horacio J; Chen, Tongwen; Riaz, Muhammad

    2005-07-01

    Principal component analysis (PCA) is a popular fault detection technique. It has been widely used in process industries, especially in the chemical industry. In industrial applications, achieving a sensitive system capable of detecting incipient faults, which maintains the false alarm rate to a minimum, is a crucial issue. Although a lot of research has been focused on these issues for PCA-based fault detection and diagnosis methods, sensitivity of the fault detection scheme versus false alarm rate continues to be an important issue. In this paper, an improved PCA method is proposed to address this problem. In this method, a new data preprocessing scheme and a new fault detection scheme designed for Hotelling's T2 as well as the squared prediction error are developed. A dynamic PCA model is also developed for boiler leak detection. This new method is applied to boiler water/steam leak detection with real data from Syncrude Canada's utility plant in Fort McMurray, Canada. Our results demonstrate that the proposed method can effectively reduce false alarm rate, provide effective and correct leak alarms, and give early warning to operators. PMID:16082787

  2. Acid pre-treatment method for in situ ore leaching

    DOEpatents

    Mallon, R.G.; Braun, R.L.

    1975-10-28

    An acid leaching method is described for the recovery of a desired element from a subterranean rubblized body of primary ore containing the element and also having associated therewith a carbonate mineral wherein the rubblized ore body is flooded with an aqueous acidic solution in order to release carbon dioxide from the associated carbonate mineral. After a substantial portion of the available carbon dioxide is released and removed from the ore body, as by venting to the atmosphere, an oxidizing gas is introduced into the flooded, rubblized ore to oxidize the ore and form an acid leach solution effective in the presence of the dissolved oxidizing gas to dissolve the ore and cause the desired element to go into solution. The leach solution is then circulated to the surface where the metal values are recovered therefrom.

  3. Screen printing of nucleic acid detecting carbon electrodes.

    PubMed

    Dequaire, Murielle; Heller, Adam

    2002-09-01

    A large fraction of the presently mass-manufactured (> 10(8) units/year) electrochemical biosensors, used mostly by diabetic people to monitor their blood glucose levels, have screen-printed carbon working electrodes. An earlier study (Campbell, C. N., et al. Anal. Chem. 2002, 74, 158-162) showed that nucleic acids can be assayed at 1 nM concentrations by a sandwich-type amperometric method. The assay was performed with vitreous carbon working electrodes on which an electron-conducting polycationic redox polymer and avidin were coelectrodeposited. Because the rate of the electrodeposition increases with the surface density of the polycationic redox polymer, its practicality depends on pretreatment of the surface, which adds anionic functions. (Gao, Z., et al. Angew. Chem. Int. Ed. 2002, 41, 810-813). Here it is shown that the required conducting redox polymer films can be electrodeposited on potentially mass manufacturable electrodes made by screen-printing hydrophilic carbon inks on polyester sheets. The modified electrodes are made in two steps. First a polycationic electron-conducting redox polymer is cross-linked and electrodeposited by applying a negative potential. Next, an amine-terminated 20-base single-stranded oligonucleotide is electrodeposited by ligand-exchange. Both steps involve exchange of a labile inner sphere chloride ligand of the polymer-bound osmium-complex: Cross-linking and electrodeposition of the redox polymer result when inner-sphere chloride anions of the osmium complexes are exchanged by imidazole functions of neighboring chains. Incorporation of the oligonucleotide in the redox polymer results in the formation of a coordinative bond between the terminal amine (attached through a spacer to the oligonucleotide) and the osmium complex. In testing for the presence of a 38-base oligonucleotide, the analyte, in a 15- or 25-microL droplet of hybridization solution, is hybridized with and captured by the 20-base electrode-bound sequence; then

  4. Development of a Generic Microfluidic Device for Simultaneous Detection of Antibodies and Nucleic Acids in Oral Fluids

    PubMed Central

    Chen, Zongyuan; Abrams, William R.; Geva, Eran; de Dood, Claudia J.; González, Jesús M.; Tanke, Hans J.; Niedbala, R. Sam; Zhou, Peng; Malamud, Daniel; Corstjens, Paul L. A. M.

    2013-01-01

    A prototype dual-path microfluidic device (Rheonix CARD) capable of performing simultaneously screening (antigen or antibody) and confirmatory (nucleic acid) detection of pathogens is described. The device fully integrates sample processing, antigen or antibody detection, and nucleic acid amplification and detection, demonstrating rapid and inexpensive “sample-to-result” diagnosis with performance comparable to benchtop analysis. For the chip design, a modular approach was followed allowing the optimization of individual steps in the sample processing process. This modular design provides great versatility accommodating different disease targets independently of the production method. In the detection module, a lateral flow (LF) protocol utilizing upconverting phosphor (UCP) reporters was employed. The nucleic acid (NA) module incorporates a generic microtube containing dry reagents. Lateral flow strips and PCR primers determine the target or disease that is diagnosed. Diagnosis of HIV infection was used as a model to investigate the simultaneous detection of both human antibodies against the virus and viral RNA. The serological result is available in less than 30 min, and the confirmation by RNA amplification takes another 60 min. This approach combines a core serological portable diagnostic with a nucleic acid-based confirmatory test. PMID:23509739

  5. Quantitative and discriminative analysis of nucleic acid samples using luminometric nonspecific nanoparticle methods

    NASA Astrophysics Data System (ADS)

    Pihlasalo, S.; Mariani, L.; Härmä, H.

    2016-03-01

    Homogeneous simple assays utilizing luminescence quenching and time-resolved luminescence resonance energy transfer (TR-LRET) were developed for the quantification of nucleic acids without sequence information. Nucleic acids prevent the adsorption of a protein to europium nanoparticles which is detected as a luminescence quenching of europium nanoparticles with a soluble quencher or as a decrease of TR-LRET from europium nanoparticles to the acceptor dye. Contrary to the existing methods based on fluorescent dye binding to nucleic acids, equal sensitivities for both single- (ssDNA) and double-stranded DNA (dsDNA) were measured and a detection limit of 60 pg was calculated for the quenching assay. The average coefficient of variation was 5% for the quenching assay and 8% for the TR-LRET assay. The TR-LRET assay was also combined with a nucleic acid dye selective to dsDNA in a single tube assay to measure the total concentration of DNA and the ratio of ssDNA and dsDNA in the mixture. To our knowledge, such a multiplexed assay is not accomplished with commercially available assays.Homogeneous simple assays utilizing luminescence quenching and time-resolved luminescence resonance energy transfer (TR-LRET) were developed for the quantification of nucleic acids without sequence information. Nucleic acids prevent the adsorption of a protein to europium nanoparticles which is detected as a luminescence quenching of europium nanoparticles with a soluble quencher or as a decrease of TR-LRET from europium nanoparticles to the acceptor dye. Contrary to the existing methods based on fluorescent dye binding to nucleic acids, equal sensitivities for both single- (ssDNA) and double-stranded DNA (dsDNA) were measured and a detection limit of 60 pg was calculated for the quenching assay. The average coefficient of variation was 5% for the quenching assay and 8% for the TR-LRET assay. The TR-LRET assay was also combined with a nucleic acid dye selective to dsDNA in a single tube

  6. Simultaneous separation and detection of actinides in acidic solutions using an extractive scintillating resin.

    PubMed

    Roane, J E; DeVol, T A

    2002-11-01

    An extractive scintillating resin was evaluated for the simultaneous separation and detection of actinides in acidic solutions. The transuranic extractive scintillating (TRU-ES) resin is composed of an inert macroporous polystyrene core impregnated with organic fluors (diphenyloxazole and 1,4-bis-(4-methyl-5-phenyl-2-oxazolyl)benzene) and an extractant (octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide in tributyl phosphate). The TRU-ES resin was packed into FEP Teflon tubing to produce a flow cell (0.2-mL free column volume), which is placed into a scintillation detection system to obtain pulse height spectra and time series data during loading and elution of actinides onto/from the resin. The alpha-particle absolute detection efficiencies ranged from 77% to 96.5%, depending on the alpha energy and quench. In addition to the on-line analyses, off-line analyses of the effluent can be conducted using conventional detection methods. The TRU-ES resin was applied to the quantification of a mixed radionuclide solution and two actual waste samples. The on-line characterization of the mixed radionuclide solution was within 10% of the reported activities whereas the agreement with the waste samples was not as good due to sorption onto the sample container walls and the oxidation state of plutonium. Agreement between the on-line and off-line analyses was within 35% of one another for both waste samples. PMID:12433098

  7. Hyperspectral anomaly detection method based on auto-encoder

    NASA Astrophysics Data System (ADS)

    Bati, Emrecan; ćalışkan, Akın.; Koz, Alper; Alatan, A. A.

    2015-10-01

    A major drawback of most of the existing hyperspectral anomaly detection methods is the lack of an efficient background representation, which can successfully adapt to the varying complexity of hyperspectral images. In this paper, we propose a novel anomaly detection method which represents the hyperspectral scenes of different complexity with the state-of-the-art representation learning method, namely auto-encoder. The proposed method first encodes the spectral image into a sparse code, then decodes the coded image, and finally, assesses the coding error at each pixel as a measure of anomaly. Predictive Sparse Decomposition Auto-encoder is utilized in the proposed anomaly method due to its efficient joint learning for the encoding and decoding functions. The performance of the proposed anomaly detection method is both tested on visible-near infrared (VNIR) and long wave infrared (LWIR) hyperspectral images and compared with the conventional anomaly detection method, namely Reed-Xiaoli (RX) detector.1 The experiments has verified the superiority of the proposed anomaly detection method in terms of receiver operating characteristics (ROC) performance.

  8. Method to detect environmental change for an arid land

    NASA Astrophysics Data System (ADS)

    Ito, A.; Miyamoto, J.; Tsuchiya, K.; Ishiyama, T.

    A method to detect natural environmental change for an arid land is developed based on 17 bands Visible NIR SWIR and Thermal IR ASTER Advanced SpaceborneThermal Emission and Reflection radiometer aboard Terra and in situ ground truth survey in Taklimakan Desert The method first extracts an area of macroscopic change then detailed or microscopic changes are detected Although the procedure is described in two steps the actual precessing is performed automatically and nearly simultaneously The method is named as ECD Environmental Change Automatic Discrimination model method for the sake of convenience

  9. Improved Hidden-Markov-Model Method Of Detecting Faults

    NASA Technical Reports Server (NTRS)

    Smyth, Padhraic J.

    1994-01-01

    Method of automated, continuous monitoring to detect faults in complicated dynamic system based on hidden-Markov-model (HMM) approach. Simpler than another, recently proposed HMM method, but retains advantages of that method, including low susceptibility to false alarms, no need for mathematical model of dynamics of system under normal or faulty conditions, and ability to detect subtle changes in characteristics of monitored signals. Examples of systems monitored by use of this method include motors, turbines, and pumps critical in their applications; chemical-processing plants; powerplants; and biomedical systems.

  10. Other Notable Methods of Membrane Protein Detection: A Brief Review.

    PubMed

    Kurien, Biji T; Scofield, R Hal

    2015-01-01

    Several techniques have been employed to detect proteins on membranes. These include the use of quantum dot luminescent labels, oxyblot immunochemical detection, polymer immunocomplexes, "coupled" probing approach, in situ renaturation of proteins for detecting enzyme activities in crude or purified preparations, immunochromatographic assay, western-phosphatase assay, and use of Congo red dye (a cosmetic color named Alta), Pro-Q Emerald 488 dye, or amine-reactive dye in combination with alkaline phosphatase- and horseradish peroxidase-antibody conjugates for the simultaneous trichromatic fluorescence detection of proteins. Several methods have been used to improve the detection of proteins on membranes, including glutaraldehyde treatment of nitrocellulose blots, elimination of keratin artifacts in immunoblots probed with polyclonal antibodies, and washing of immunoblots with excessive water and manipulation of Tween-20 in wash buffer. These methods are briefly reviewed in this chapter. PMID:26139283

  11. Automatic landslide and mudflow detection method via multichannel sparse representation

    NASA Astrophysics Data System (ADS)

    Chao, Chen; Zhou, Jianjun; Hao, Zhuo; Sun, Bo; He, Jun; Ge, Fengxiang

    2015-10-01

    Landslide and mudflow detection is an important application of aerial images and high resolution remote sensing images, which is crucial for national security and disaster relief. Since the high resolution images are often large in size, it's necessary to develop an efficient algorithm for landslide and mudflow detection. Based on the theory of sparse representation and, we propose a novel automatic landslide and mudflow detection method in this paper, which combines multi-channel sparse representation and eight neighbor judgment methods. The whole process of the detection is totally automatic. We make the experiment on a high resolution image of ZhouQu district of Gansu province in China on August, 2010 and get a promising result which proved the effective of using sparse representation on landslide and mudflow detection.

  12. DNA Diagnostics: Nanotechnology-enhanced Electrochemical Detection of Nucleic Acids

    PubMed Central

    Wei, Fang; Lillehoj, Peter B.; Ho, Chih-Ming

    2010-01-01

    The detection of mismatched base pairs in DNA plays a crucial role in the diagnosis of genetic-related diseases and conditions, especially for early stage treatment. Among the various biosensors that have been employed for DNA detection, electrochemical sensors show great promise since they are capable of precise DNA recognition and efficient signal transduction. Advancements in micro- and nanotechnologies, specifically fabrication techniques and new nanomaterials, have enabled for the development of highly sensitive, highly specific sensors making them attractive for the detection of small sequence variations. Furthermore, the integration of sensors with sample preparation and fluidic processes enables for rapid, multiplexed DNA detection for point-of-care (POC) clinical diagnostics. PMID:20075759

  13. Considerations on the use of nucleic acid-based amplification for malaria parasite detection

    PubMed Central

    2011-01-01

    Background Nucleic acid amplification provides the most sensitive and accurate method to detect and identify pathogens. This is primarily useful for epidemiological investigations of malaria because the infections, often with two or more Plasmodium species present simultaneously, are frequently associated with microscopically sub-patent parasite levels and cryptic mixed infections. Numerous distinct equally adequate amplification-based protocols have been described, but it is unclear which to select for epidemiological surveys. Few comparative studies are available, and none that addresses the issue of inter-laboratory variability. Methods Blood samples were collected from patients attending malaria clinics on the Thai-Myanmar border. Frozen aliquots from 413 samples were tested independently in two laboratories by nested PCR assay. Dried blood spots on filter papers from the same patients were also tested by the nested PCR assay in one laboratory and by a multiplex PCR assay in another. The aim was to determine which protocol best detected parasites below the sensitivity level of microscopic examination. Results As expected PCR-based assays detected a substantial number of infected samples, or mixed infections, missed by microscopy (27 and 42 for the most sensitive assay, respectively). The protocol that was most effective at detecting these, in particular mixed infections, was a nested PCR assay with individual secondary reactions for each of the species initiated with a template directly purified from the blood sample. However, a lesser sensitivity in detection was observed when the same protocol was conducted in another laboratory, and this significantly altered the data obtained on the parasite species distribution. Conclusions The sensitivity of a given PCR assay varies between laboratories. Although, the variations are relatively minor, they primarily diminish the ability to detect low-level and mixed infections and are sufficient to obviate the main

  14. CRISPR Spacer Arrays for Detection of Viral Signatures from Acidic Hot Springs

    NASA Astrophysics Data System (ADS)

    Snyder, J. C.; Bateson, M. M.; Suciu, D.; Young, M. J.

    2010-04-01

    Viruses are the most abundant life-like entities on the planet Earth. Using CRISPR spacer sequences, we have developed a microarray-based approach to detecting viral signatures in the acidic hot springs of Yellowstone.

  15. Detection of nucleic acid-nuclear hormone receptor complexes with mass spectrometry.

    PubMed

    Bich, Claudia; Bovet, Cédric; Rochel, Natacha; Peluso-Iltis, Carole; Panagiotidis, Andreas; Nazabal, Alexis; Moras, Dino; Zenobi, Renato

    2010-04-01

    Nuclear receptors, such as the retinoic acid receptor (RAR) or the 9-cis retinoic acid receptor (RXR), interact not only with their ligands but also with other types of receptors and with DNA. Here, two complementary mass spectrometry (MS) methods were used to study the interactions between retinoic receptors (RXR/RAR) and DNA: non-denaturing nano-electrospray (nanoESI MS), and high-mass matrix-assisted laser desorption ionization (MALDI MS) combined with chemical cross-linking. The RAR x RXR heterodimer was studied in the presence of a specific DNA sequence (DR5), and a specific RAR x RXR x DNA complex was detected with both MS techniques. RAR by itself showed no significant homodimerization. A complex between RAR and the double stranded DR5 was detected with nanoESI. After cross-linking, high-mass MALDI mass spectra showed that the RAR binds the single stranded DR5, and the RAR dimer binds both single and double stranded DR5. Moreover, the MALDI mass spectrum shows a larger RAR dimer signal in the presence of DNA. These results suggest that a gene-regulatory site on DNA can induce quaternary structural changes in a transcription factor such as RAR. PMID:20097575

  16. Reverse Transcription Cross-Priming Amplification-Nucleic Acid Test Strip for Rapid Detection of Porcine Epidemic Diarrhea Virus.

    PubMed

    Wang, Feng-Xue; Yuan, Dan-Yi; Jin, Ya-Nan; Hu, Lin; Sun, Zhi-Yong; He, Qian; Zhao, Shi-Hua; Zhan, Shu-Bai; Wen, Yong-Jun

    2016-01-01

    Porcine epidemic diarrhea virus (PEDV) is a highly transmissible coronavirus that causes a severe enteric disease particularly in neonatal piglets. In this study, a rapid method for detecting PEDV was developed based on cross-priming amplification and nucleic acid test strip(CPA-NATS). Five primers specific for the N gene sequence of PEDV were used for the cross-priming amplification. Detection of amplification products based on labeled probe primers was conducted with strip binding antibody of labeled markers. The CPA method was evaluated and compared with a PCR method. The reverse transcription CPA system was further optimized for detecting PEDV RNA in clinical specimens. Results showed that the method was highly specific for the detection of PEDV, and had the same sensitivity as PCR, with detection limit of 10(-6) diluted plasmid containing the target gene of PEDV. It was also successfully applied to detecting PEDV in clinical specimens. The reverse transcription CPA-NATS detection system established in this study offers a specific, sensitive, rapid, and simple detection tool for screening PEDV, which can contribute to strategies in the effective control of PEDV in swine. PMID:27090105

  17. Reverse Transcription Cross-Priming Amplification–Nucleic Acid Test Strip for Rapid Detection of Porcine Epidemic Diarrhea Virus

    PubMed Central

    Wang, Feng-Xue; Yuan, Dan-Yi; Jin, Ya-Nan; Hu, Lin; Sun, Zhi-Yong; He, Qian; Zhao, Shi-Hua; Zhan, Shu-Bai; Wen, Yong-Jun

    2016-01-01

    Porcine epidemic diarrhea virus (PEDV) is a highly transmissible coronavirus that causes a severe enteric disease particularly in neonatal piglets. In this study, a rapid method for detecting PEDV was developed based on cross-priming amplification and nucleic acid test strip(CPA-NATS). Five primers specific for the N gene sequence of PEDV were used for the cross-priming amplification. Detection of amplification products based on labeled probe primers was conducted with strip binding antibody of labeled markers. The CPA method was evaluated and compared with a PCR method. The reverse transcription CPA system was further optimized for detecting PEDV RNA in clinical specimens. Results showed that the method was highly specific for the detection of PEDV, and had the same sensitivity as PCR, with detection limit of 10−6 diluted plasmid containing the target gene of PEDV. It was also successfully applied to detecting PEDV in clinical specimens. The reverse transcription CPA-NATS detection system established in this study offers a specific, sensitive, rapid, and simple detection tool for screening PEDV, which can contribute to strategies in the effective control of PEDV in swine. PMID:27090105

  18. Methods, systems and devices for detecting and locating ferromagnetic objects

    DOEpatents

    Roybal, Lyle Gene [Idaho Falls, ID; Kotter, Dale Kent [Shelley, ID; Rohrbaugh, David Thomas [Idaho Falls, ID; Spencer, David Frazer [Idaho Falls, ID

    2010-01-26

    Methods for detecting and locating ferromagnetic objects in a security screening system. One method includes a step of acquiring magnetic data that includes magnetic field gradients detected during a period of time. Another step includes representing the magnetic data as a function of the period of time. Another step includes converting the magnetic data to being represented as a function of frequency. Another method includes a step of sensing a magnetic field for a period of time. Another step includes detecting a gradient within the magnetic field during the period of time. Another step includes identifying a peak value of the gradient detected during the period of time. Another step includes identifying a portion of time within the period of time that represents when the peak value occurs. Another step includes configuring the portion of time over the period of time to represent a ratio.

  19. A carbon dot-based "off-on" fluorescent probe for highly selective and sensitive detection of phytic acid.

    PubMed

    Gao, Zhao; Wang, Libing; Su, Rongxin; Huang, Renliang; Qi, Wei; He, Zhimin

    2015-08-15

    We herein report a facile, one-step pyrolysis synthesis of photoluminescent carbon dots (CDs) using citric acid as the carbon source and lysine as the surface passivation reagent. The as-prepared CDs show narrow size distribution, excellent blue fluorescence and good photo-stability and water dispersivity. The fluorescence of the CDs was found to be effectively quenched by ferric (Fe(III)) ions with high selectivity via a photo-induced electron transfer (PET) process. Upon addition of phytic acid (PA) to the CDs/Fe(III) complex dispersion, the fluorescence of the CDs was significantly recovered, arising from the release of Fe(III) ions from the CDs/Fe(III) complex because PA has a higher affinity for Fe(III) ions compared to CDs. Furthermore, we developed an "off-on" fluorescence assay method for the detection of phytic acid using CDs/Fe(III) as a fluorescent probe. This probe enables the selective detection of PA with a linear range of 0.68-18.69 μM and a limit of detection (signal-to-noise ratio is 3) of 0.36 μM. The assay method demonstrates high selectivity, repeatability, stability and recovery ratio in the detection of the standard and real PA samples. We believe that the facile operation, low-cost, high sensitivity and selectivity render this CD-based "off-on" fluorescent probe an ideal sensing platform for the detection of PA. PMID:25829220

  20. Poly(o-aminophenol)-modified bienzyme carbon paste electrode for the detection of uric acid.

    PubMed

    Miland, E; Miranda Ordieres, A J; Tuñón Blanco, P; Smyth, M R; Fágáin, C O

    1996-05-01

    A reagentless uric acid selective biosensor constructed by immobilising uricase and horseradish peroxidase (HRP) in carbon paste without the addition of an electron transfer mediator is described. The response of the electrode is based on the enzymatic reduction of hydrogen peroxide in the presence of uric acid. Uricase and HRP were dispersed in the carbon paste and the optimum paste mixture was determined. Poly(o-aminophenol) was electropolymerised at the working surface area of the electrode acting as a conducting polymer layer. Cyclic voltammetry was used to characterise the permselective characteristics of the polymer layer. At an applied potential of 50 mV vs. Ag/AgCl, a linear response was obtained up to 1 x 10(-4) M, with a limit of detection of 3 x 10(-6) M. The sensor had a response time of 37 s. a calibration precision of 2.2% (n = 4) and an estimated sample frequency of 20 h(-1). Responses to the analyte of interest were pH dependent. The sensor was incorporated into a flow injection system for the qualification of uric acid in human serum. Results compared favourably with a standard spectrophotometric method. PMID:18966549

  1. A Nucleic Acid Biosensor for Detection of Hepatitis C Virus Genotype 1a Using Poly(L-Glutamic Acid)-Modified Electrode.

    PubMed

    Donmez, Soner; Arslan, Fatma; Arslan, Halit

    2015-07-01

    An electrochemical nucleic acid biosensor based on label-free DNA detection method was prepared for the first time by using electropolymerized poly(L-glutamic acid)-modified pencil graphite electrode (PGA/PGE) for detection of hepatitis C virus genotype 1a (HCV1a). Inosine-substituted 20-mer probes related to the HCV1a were immobilized onto PGA/PGE surface by covalent linking with the formation of amide bonds. Square wave voltammetry (SWV) was used to monitor the oxidation signal of guanine in the hybridization events, which gave an oxidation peak at +1.05 V. An increase in the oxidation signal of guanine was showed by hybridization of the probe with the complementary DNA. Noncomplementary oligonucleotides were also used to investigate the selectivity of the biosensor. The proposed nucleic acid biosensor was linear in the range of 50 nM to 1.0 μM, exhibiting a limit of detection of 40.6 nM. Finally, single-stranded synthetic PCR product analogues of HCV1a were performed in optimal condition. This PGA-modified nucleic acid sensor is cost-effective and disposable, and besides, it has superior electrocatalytic effect on the oxidation of guanine. PMID:25947619

  2. LC/ESI-MS/MS method for determination of salivary eicosapentaenoic acid concentration to arachidonic acid concentration ratio.

    PubMed

    Ogawa, Shoujiro; Tomaru, Koki; Matsumoto, Nagisa; Watanabe, Shui; Higashi, Tatsuya

    2016-01-01

    A simple liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for determination of the eicosapentaenoic acid (EPA) concentration to arachidonic acid (AA) concentration ratio in human saliva has been developed. The EPA/AA ratio in serum or plasma is widely recognized as a useful indicator in identifying the risk of cardiovascular disease, especially atherosclerosis. The salivary EPA/AA ratio is expected to be a convenient alternative to the serum or plasma EPA/AA ratio, because saliva offers the advantages of easy and noninvasive sampling. The saliva was deproteinized with acetonitrile, purified using an Oasis HLB cartridge, and derivatized with 1-[(4-dimethylaminophenyl)carbonyl]piperazine (DAPPZ). The derivatized EPA and AA were subjected to LC/ESI-MS/MS, and the EPA/AA ratio was determined using the selected reaction monitoring mode. The DAPPZ-derivatization increased the ESI sensitivity by 100- and 300-fold for EPA and AA, respectively, and enabled the detection of trace fatty acids in saliva using a 200 μL sample. The assay reproducibility was satisfactory (relative standard deviation, <5.0%). The method was successfully applied to the measurement of the salivary EPA/AA ratios of healthy Japanese subjects and their changes owing to the supplementation of EPA. PMID:25620210

  3. Preparation of polyaniline nanostructures doped with different dicarboxylic acids through template-free method

    NASA Astrophysics Data System (ADS)

    Sun, Chuanyu; Wang, Yu

    2014-09-01

    In this article nanoscaled polyanilines (PANI) were prepared based on template-free method in the presence of dicarboxylic acid dopants (e.g. D-tartaric acid, succinic acid, maleic acid and fumaric acid). The trans-cis isomerization of butenedioic acid played an important role in the formation of nanostructures from the plane-like to nanofibers, and the PANI doped with maleic acid (MA) had larger diameter, higher crystallinity and conductivity than PANI doped with fumaric acid (FA).

  4. Method for liquid chromatographic extraction of strontium from acid solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1992-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  5. New method for administration of hydrochloric acid in metabolic alkalosis.

    PubMed

    Knutsen, O H

    1983-04-30

    In a new method for peripheral intravenous infusion of hydrochloric acid the HCl is buffered in an aminoacid solution and infused with a fat emulsion. The aminoacids and the fat emulsions are stable in the presence of HCl, and the transfusion set is resistant to the chemical actin of 0.15 mol/l HCl. Two case-reports show that HCl can be administered safely through a peripheral vein. PMID:6132269

  6. Vadose Zone Sampling Methods for Detection of Preferential Pesticides Transport

    NASA Astrophysics Data System (ADS)

    Peranginangin, N.; Richards, B. K.; Steenhuis, T. S.

    2003-12-01

    Leaching of agricultural applied chemicals through the vadose zone is a major cause for the occurrence of agrichemicals in groundwater. Accurate soil water sampling methods are needed to ensure meaningful monitoring results, especially for soils that have significant preferential flow paths. The purpose of this study was to assess the capability and the effectiveness of various soil water sampling methods in detecting preferential transport of pesticides in a strongly-structured silty clay loam (Hudson series) soil. Soil water sampling devices tested were wick pan and gravity pan lysimeters, tile lines, porous ceramic cups, and pipe lysimeters; all installed at 45 to105 cm depth below the ground surface. A reasonable worse-case scenario was tested by applying a simulated rain storm soon after pesticides were sprayed at agronomic rates. Herbicides atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) and 2,4-D (2,4-dichloro-phenoxyacetic acid) were chosen as model compounds. Chloride (KCl) tracer was used to determine spatial and temporal distribution of non-reactive solute and water as well as a basis for determining the retardation in pesticides movement. Results show that observed pesticide mobility was much greater than would be predicted by uniform flow. Under relatively high soil moisture conditions, gravity and wick pan lysimeters had comparably good collection efficiencies, whereas the wick samplers had an advantage over gravity driven sampler when the soil moisture content was below field capacity. Pipe lysimeters had breakthrough patterns that were similar to pan samplers. At small plot scale, tile line samplers tended to underestimate solute concentration because of water dilution around the samplers. The use of porous cup samplers performed poorly because of their sensitivity to local profile characteristics: only by chance can they intercept and sample the preferential flow paths that are critical to transport. Wick sampler had the least

  7. Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

    PubMed

    Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

    2016-10-20

    In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. PMID:27474618

  8. [An Effective Wavelength Detection Method Based on Echelle Spectra Reduction].

    PubMed

    Yin, Lu; Bayanheshig; Cui, Ji-cheng; Yang, Jin; Zhu, Ji-wei; Yao, Xue-feng

    2015-03-01

    Echelle spectrometer with high dispersion, high resolution, wide spectral coverage, full spectrum transient direct-reading and many other advantages, is one of the representative of the advanced spectrometer. In the commercialization trend of echelle spectrometer, the method of two-dimension spectra image processing is becoming more and more important. Currently, centroid extraction algorithm often be used first to detect the centroid position of effective facula and then combined with echelle spectrum reduction method to detect the effective wavelength, but this method is more difficult to achieve the desired requirements. To improve the speed, accuracy and the ability of imaging error correction during detecting the effective wavelength, an effective wavelength detection method based on spectra reduction is coming up. At the beginning, the two-dimension spectra will be converted to a one-dimension image using echelle spectra reduction method instead of finding centroid of effective facula. And then by setting appropriate threshold the one-dimension image is easy to be dealing with than the two-dimension spectra image and all of the pixel points stand for effective wavelength can be detected at one time. Based on this new idea, the speed and accuracy of image processing have been improved, at the same time a range of imaging errors can be compensated. Using the echelle spectrograph make a test applying this algorithm for data processing to check whether this method is fit for the spectra image processing or not. Choosing a standard mercury lamp as a light source during the test because the standard mercury lamp have a number of known characteristic lines which can be used to examine the accuracy of wavelength detection. According to experimental result, this method not only increase operation speed but improve accuracy of wavelength detection, also the imaging error lower than 0.05 mm (two pixel) can be corrected, and the wavelength accuracy would up to 0.02 nm

  9. Dirichlet Methods for Bayesian Source Detection in Radio Astronomy Images

    NASA Astrophysics Data System (ADS)

    Friedlander, A. M.

    2014-02-01

    The sheer volume of data to be produced by the next generation of radio telescopes - exabytes of data on hundreds of millions of objects - makes automated methods for the detection of astronomical objects ("sources") essential. Of particular importance are low surface brightness objects, which are not well found by current automated methods. This thesis explores Bayesian methods for source detection that use Dirichlet or multinomial models for pixel intensity distributions in discretised radio astronomy images. A novel image discretisation method that incorporates uncertainty about how the image should be discretised is developed. Latent Dirichlet allocation - a method originally developed for inferring latent topics in document collections - is used to estimate source and background distributions in radio astronomy images. A new Dirichlet-multinomial ratio, indicating how well a region conforms to a well-specified model of background versus a loosely-specified model of foreground, is derived. Finally, latent Dirichlet allocation and the Dirichlet-multinomial ratio are combined for source detection in astronomical images. The methods developed in this thesis perform source detection well in comparison to two widely-used source detection packages and, importantly, find dim sources not well found by other algorithms.

  10. A Method for Detecting Positive Growth Autocorrelation without Marking Individuals

    PubMed Central

    Brooks, Mollie E.; McCoy, Michael W.; Bolker, Benjamin M.

    2013-01-01

    In most ecological studies, within-group variation is a nuisance that obscures patterns of interest and reduces statistical power. However, patterns of within-group variability often contain information about ecological processes. In particular, such patterns can be used to detect positive growth autocorrelation (consistent variation in growth rates among individuals in a cohort across time), even in samples of unmarked individuals. Previous methods for detecting autocorrelated growth required data from marked individuals. We propose a method that requires only estimates of within-cohort variance through time, using maximum likelihood methods to obtain point estimates and confidence intervals of the correlation parameter. We test our method on simulated data sets and determine the loss in statistical power due to the inability to identify individuals. We show how to accommodate nonlinear growth trajectories and test the effects of size-dependent mortality on our method's accuracy. The method can detect significant growth autocorrelation at moderate levels of autocorrelation with moderate-sized cohorts (for example, statistical power of 80% to detect growth autocorrelation ρ2 = 0.5 in a cohort of 100 individuals measured on 16 occasions). We present a case study of growth in the red-eyed tree frog. Better quantification of the processes driving size variation will help ecologists improve predictions of population dynamics. This work will help researchers to detect growth autocorrelation in cases where marking is logistically infeasible or causes unacceptable decreases in the fitness of marked individuals. PMID:24204620

  11. A method for detecting positive growth autocorrelation without marking individuals.

    PubMed

    Brooks, Mollie E; McCoy, Michael W; Bolker, Benjamin M

    2013-01-01

    In most ecological studies, within-group variation is a nuisance that obscures patterns of interest and reduces statistical power. However, patterns of within-group variability often contain information about ecological processes. In particular, such patterns can be used to detect positive growth autocorrelation (consistent variation in growth rates among individuals in a cohort across time), even in samples of unmarked individuals. Previous methods for detecting autocorrelated growth required data from marked individuals. We propose a method that requires only estimates of within-cohort variance through time, using maximum likelihood methods to obtain point estimates and confidence intervals of the correlation parameter. We test our method on simulated data sets and determine the loss in statistical power due to the inability to identify individuals. We show how to accommodate nonlinear growth trajectories and test the effects of size-dependent mortality on our method's accuracy. The method can detect significant growth autocorrelation at moderate levels of autocorrelation with moderate-sized cohorts (for example, statistical power of 80% to detect growth autocorrelation ρ (2) = 0.5 in a cohort of 100 individuals measured on 16 occasions). We present a case study of growth in the red-eyed tree frog. Better quantification of the processes driving size variation will help ecologists improve predictions of population dynamics. This work will help researchers to detect growth autocorrelation in cases where marking is logistically infeasible or causes unacceptable decreases in the fitness of marked individuals. PMID:24204620

  12. Bayesian methods for discontinuity detection in climate model predictions.

    SciTech Connect

    Safta, Cosmin; Debusschere, Bert J.; Najm, Habib N.; Sargsyan, Khachik

    2010-06-01

    Discontinuity detection is an important component in many fields: Image recognition, Digital signal processing, and Climate change research. Current methods shortcomings are: Restricted to one- or two-dimensional setting, Require uniformly spaced and/or dense input data, and Give deterministic answers without quantifying the uncertainty. Spectral methods for Uncertainty Quantification with global, smooth bases are challenged by discontinuities in model simulation results. Domain decomposition reduces the impact of nonlinearities and discontinuities. However, while gaining more smoothness in each subdomain, the current domain refinement methods require prohibitively many simulations. Therefore, detecting discontinuities up front and refining accordingly provides huge improvement to the current methodologies.

  13. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS: DETECTION AND QUANTITATION ISSUES AT LOW CONCENTRATIONS

    EPA Science Inventory

    Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can...

  14. Indirect target detection method in FLIR image sequences

    NASA Astrophysics Data System (ADS)

    Zhu, Hu; Zhang, Tianxu; Deng, Lizhen

    2013-09-01

    Due to the complexity of the scene, target detection in forward-looking infrared (FLIR) imagery is a challenging problem, especially for occluded target. The main contribution of this paper is to propose an indirect detection method for improving the recognition probability and effectiveness of target detection method in FLIR image sequences under complex conditions. The proposed method mainly includes four steps: preparation of forward-looking reference image of landmark, extraction of the real-time scene image, template matching and target location, in which some key technologies are proposed, such as perspective transformation used to solve projective problems, position prediction for improving real-time performance, and target location used for identifying the target's position. Experimental results are shown to demonstrate the robustness and efficiency of proposed method in FLIR image sequences.

  15. A Bayesian Outbreak Detection Method for Influenza-Like Illness

    PubMed Central

    García, Yury E.; Christen, J. Andrés; Capistrán, Marcos A.

    2015-01-01

    Epidemic outbreak detection is an important problem in public health and the development of reliable methods for outbreak detection remains an active research area. In this paper we introduce a Bayesian method to detect outbreaks of influenza-like illness from surveillance data. The rationale is that, during the early phase of the outbreak, surveillance data changes from autoregressive dynamics to a regime of exponential growth. Our method uses Bayesian model selection and Bayesian regression to identify the breakpoint. No free parameters need to be tuned. However, historical information regarding influenza-like illnesses needs to be incorporated into the model. In order to show and discuss the performance of our method we analyze synthetic, seasonal, and pandemic outbreak data. PMID:26425552

  16. Laboratory Detection and Analysis of Organic Compounds in Rocks Using HPLC and XRD Methods

    NASA Technical Reports Server (NTRS)

    Dragoi, D.; Kanik, I.; Bar-Cohen, Y.; Sherrit, S.; Tsapin, A.; Kulleck, J.

    2004-01-01

    In this work we describe an analytical method for determining the presence of organic compounds in rocks, limestone, and other composite materials. Our preliminary laboratory experiments on different rocks/limestone show that the organic component in mineralogical matrices is a minor phase on order of hundreds of ppm and can be better detected using high precision liquid chromatography (HPLC). The matrix, which is the major phase, plays an important role in embedding and protecting the organic molecules from the harsh Martian environment. Some rocks bear significant amounts of amino acids therefore, it is possible to identify these phases using powder x-ray diffraction (XRD) by crystallizing the organic. The method of detection/analysis of organics, in particular amino acids, that have been associated with life will be shown in the next section.

  17. Quantitative detection of uric acid by electrochemical-surface enhanced Raman spectroscopy using a multilayered Au/Ag substrate.

    PubMed

    Zhao, Lili; Blackburn, Jonathan; Brosseau, Christa L

    2015-01-01

    Uric acid is a potential important biomarker in urine and serum samples for early diagnosis of preeclampsia, a life-threatening hypertensive disorder that occurs during pregnancy. Preeclampsia is a leading cause of maternal death, especially in developing nation settings. Quantitative detection of uric acid for rapid and routine diagnosis of early preeclampsia using electrochemical-surface enhanced Raman spectroscopy (EC-SERS) is presented herein. A uniform EC-SERS active Au/Ag substrate was developed by depositing nearly monodisperse gold and silver nanoparticles on the carbon working electrode surface of screen printed electrodes. The multilayered Au/Ag substrates were characterized by electron microscopy and used for quantitative detection of uric acid in 0.1 M NaF and synthetic urine at clinically relevant concentrations. These results showed a linear relationship between the EC-SERS signal intensity and the uric acid concentration. Relative errors calculated for selected concentrations were all within the Clinical Laboratory Improvement Amendments (CLIA) criterion for uric acid analysis (±17%). It is believed that routine and early diagnosis of disease could be possible through such quantitative detection of biomarkers in patient samples using this EC-SERS method. PMID:25483146

  18. High sensitive method detection of plant RNA viruses by electrochemiluminescence reverse transcription PCR

    NASA Astrophysics Data System (ADS)

    Tang, Ya-bing; Xing, Da; Zhu, De-bin; Zhou, Xiao-ming

    2007-05-01

    It is well known that plant and animal viruses had widely spread the whole of world, and made a big loss in farming and husbandry. It is necessary that a highly efficient and accurate virus's detection method was developed. This research combines reverse transcription polymerase chain reaction (RT-PCR) technique with electrochemiluminescence method, to detect plant RNA viruses for the first time. Biotin-probe hybridizes with PCR product to specific select the target for detection, thus can avoid pseudo-positive result. TBR-probe hybridizes with PCR product to emit light for ECL detection. Specific nucleic acid sequences (20bp) were added to 5' terminal all of the primers, which can improve the chance of hybridization between TBR-probe and PCR product. At the same time, one of the PCR product chain can hybridize two Ru-probes, the ECL signal is intensified. The method was used to detect Odntoglossum ringspot virus ORSV, Sugarcane mosaic virus ScMV, Sorghum mosaic virus SrMV, and Maize dwarf mosaic virus MDMV, the experiment results show that this method could reliably identity virus infected plant samples. In a word, this method has higher sensitivity and lower cost than others. It can effectively detect the plant viruses with simplicity, stability, and high sensitivity.

  19. Detection of a CO and NH3 gas mixture using carboxylic acid-functionalized single-walled carbon nanotubes

    PubMed Central

    2013-01-01

    Carbon nanotubes (CNT) are extremely sensitive to environmental gases. However, detection of mixture gas is still a challenge. Here, we report that 10 ppm of carbon monoxide (CO) and ammonia (NH3) can be electrically detected using a carboxylic acid-functionalized single-walled carbon nanotubes (C-SWCNT). CO and NH3 gases were mixed carefully with the same concentrations of 10 ppm. Our sensor showed faster response to the CO gas than the NH3 gas. The sensing properties and effect of carboxylic acid group were demonstrated, and C-SWCNT sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective detection method of CO and NH3 mixture gas. PMID:23286690

  20. Methods and systems for remote detection of gases

    DOEpatents

    Johnson, Timothy J

    2012-09-18

    Novel systems and methods for remotely detecting at least one constituent of a gas via infrared detection are provided. A system includes at least one extended source of broadband infrared radiation and a spectrally sensitive receiver positioned remotely from the source. The source and the receiver are oriented such that a surface of the source is in the field of view of the receiver. The source includes a heating component thermally coupled to the surface, and the heating component is configured to heat the surface to a temperature above ambient temperature. The receiver is operable to collect spectral infrared absorption data representative of a gas present between the source and the receiver. The invention advantageously overcomes significant difficulties associated with active infrared detection techniques known in the art, and provides an infrared detection technique with a much greater sensitivity than passive infrared detection techniques known in the art.

  1. Methods and systems for remote detection of gases

    DOEpatents

    Johnson, Timothy J.

    2007-11-27

    Novel systems and methods for remotely detecting at least one constituent of a gas via infrared detection are provided. A system includes at least one extended source of broadband infrared radiation and a spectrally sensitive receiver positioned remotely from the source. The source and the receiver are oriented such that a surface of the source is in the field of view of the receiver. The source includes a heating component thermally coupled to the surface, and the heating component is configured to heat the surface to a temperature above ambient temperature. The receiver is operable to collect spectral infrared absorption data representative of a gas present between the source and the receiver. The invention advantageously overcomes significant difficulties associated with active infrared detection techniques known in the art, and provides an infrared detection technique with a much greater sensitivity than passive infrared detection techniques known in the art.

  2. Transistor-based particle detection systems and methods

    DOEpatents

    Jain, Ankit; Nair, Pradeep R.; Alam, Muhammad Ashraful

    2015-06-09

    Transistor-based particle detection systems and methods may be configured to detect charged and non-charged particles. Such systems may include a supporting structure contacting a gate of a transistor and separating the gate from a dielectric of the transistor, and the transistor may have a near pull-in bias and a sub-threshold region bias to facilitate particle detection. The transistor may be configured to change current flow through the transistor in response to a change in stiffness of the gate caused by securing of a particle to the gate, and the transistor-based particle detection system may configured to detect the non-charged particle at least from the change in current flow.

  3. Detection of forced oscillations in power systems with multichannel methods

    SciTech Connect

    Follum, James D.

    2015-09-30

    The increasing availability of high fidelity, geographically dispersed measurements in power systems improves the ability of researchers and engineers to study dynamic behaviors in the grid. One such behavior that is garnering increased attention is the presence of forced oscillations. Power system engineers are interested in forced oscillations because they are often symptomatic of the malfunction or misoperation of equipment. Though the resulting oscillation is not always large in amplitude, the root cause may be serious. In this report, multi-channel forced oscillation detection methods are developed. These methods leverage previously developed detection approaches based on the periodogram and spectral-coherence. Making use of geographically distributed channels of data is shown to improved detection performance and shorten the delay before an oscillation can be detected in the online environment. Results from simulated and measured power system data are presented.

  4. Detecting diversity: emerging methods to estimate species diversity.

    PubMed

    Iknayan, Kelly J; Tingley, Morgan W; Furnas, Brett J; Beissinger, Steven R

    2014-02-01

    Estimates of species richness and diversity are central to community and macroecology and are frequently used in conservation planning. Commonly used diversity metrics account for undetected species primarily by controlling for sampling effort. Yet the probability of detecting an individual can vary among species, observers, survey methods, and sites. We review emerging methods to estimate alpha, beta, gamma, and metacommunity diversity through hierarchical multispecies occupancy models (MSOMs) and multispecies abundance models (MSAMs) that explicitly incorporate observation error in the detection process for species or individuals. We examine advantages, limitations, and assumptions of these detection-based hierarchical models for estimating species diversity. Accounting for imperfect detection using these approaches has influenced conclusions of comparative community studies and creates new opportunities for testing theory. PMID:24315534

  5. New Optical Methods for Liveness Detection on Fingers

    PubMed Central

    Dolezel, Michal; Vana, Jan; Brezinova, Eva; Yim, Jaegeol; Shim, Kyubark

    2013-01-01

    This paper is devoted to new optical methods, which are supposed to be used for liveness detection on fingers. First we describe the basics about fake finger use in fingerprint recognition process and the possibilities of liveness detection. Then we continue with introducing three new liveness detection methods, which we developed and tested in the scope of our research activities—the first one is based on measurement of the pulse, the second one on variations of optical characteristics caused by pressure change, and the last one is based on reaction of skin to illumination with different wavelengths. The last part deals with the influence of skin diseases on fingerprint recognition, especially on liveness detection. PMID:24151584

  6. A direct RP-HPLC method for the determination of furanic aldehydes and acids in honey.

    PubMed

    Spano, Nadia; Ciulu, Marco; Floris, Ignazio; Panzanelli, Angelo; Pilo, Maria I; Piu, Paola C; Salis, Severyn; Sanna, Gavino

    2009-04-15

    In this study 5-hydroxymethyl-2-furaldehyde (HMF), 2-furaldehyde, 3-furaldehyde, 2-furoic acid and 3-furoic acid are contemporarily determined in honey using a swift and direct RP-HPLC approach. The validation protocol was performed in terms of detection and quantification limits, precision (by repeatability and reproducibility), linearity and accuracy (by recovery tests); the acceptability of the precision and accuracy results was positively verified using Horwitz's model and AOAC guidelines, respectively. The method was tested on 18 honey samples of different ages, and botanical and geographical origin. HMF and 2-furaldehyde correlated highly with the age of the samples, whereas no correlation was observed with regards to 2-furaldehyde and 2-furoic acid. Hypotheses relating to the formation of minority furanic compounds are also proposed. PMID:19174244

  7. EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 30, METHOD 625 - BASE/NEUTRALS, ACIDS AND PESTICIDES

    EPA Science Inventory

    The work which is described in this report was performed for the purpose of validating, through an interlaboratory study, Method 625 for the analysis of the base/neutral, acid, and pesticide priority pollutants. This method is based on the extraction and concentration of the vari...

  8. Mass spectrometric detection of the amino acid sequence polymorphism of the hepatitis C virus antigen.

    PubMed

    Kaysheva, A L; Ivanov, Yu D; Frantsuzov, P A; Krohin, N V; Pavlova, T I; Uchaikin, V F; Konev, V А; Kovalev, O B; Ziborov, V S; Archakov, A I

    2016-03-01

    A method for detection and identification of the hepatitis C virus antigen (HCVcoreAg) in human serum with consideration for possible amino acid substitutions is proposed. The method is based on a combination of biospecific capturing and concentrating of the target protein on the surface of the chip for atomic force microscope (AFM chip) with subsequent protein identification by tandem mass spectrometric (MS/MS) analysis. Biospecific AFM-capturing of viral particles containing HCVcoreAg from serum samples was performed by use of AFM chips with monoclonal antibodies (anti-HCVcore) covalently immobilized on the surface. Biospecific complexes were registered and counted by AFM. Further MS/MS analysis allowed to reliably identify the HCVcoreAg in the complexes formed on the AFM chip surface. Analysis of MS/MS spectra, with the account taken of the possible polymorphisms in the amino acid sequence of the HCVcoreAg, enabled us to increase the number of identified peptides. PMID:26773170

  9. Maximum patch method for directional dark matter detection

    SciTech Connect

    Henderson, Shawn; Monroe, Jocelyn; Fisher, Peter

    2008-07-01

    Present and planned dark matter detection experiments search for WIMP-induced nuclear recoils in poorly known background conditions. In this environment, the maximum gap statistical method provides a way of setting more sensitive cross section upper limits by incorporating known signal information. We give a recipe for the numerical calculation of upper limits for planned directional dark matter detection experiments, that will measure both recoil energy and angle, based on the gaps between events in two-dimensional phase space.

  10. Safety assessment and detection methods of genetically modified organisms.

    PubMed

    Xu, Rong; Zheng, Zhe; Jiao, Guanglian

    2014-01-01

    Genetically modified organisms (GMOs), are gaining importance in agriculture as well as the production of food and feed. Along with the development of GMOs, health and food safety concerns have been raised. These concerns for these new GMOs make it necessary to set up strict system on food safety assessment of GMOs. The food safety assessment of GMOs, current development status of safety and precise transgenic technologies and GMOs detection have been discussed in this review. The recent patents about GMOs and their detection methods are also reviewed. This review can provide elementary introduction on how to assess and detect GMOs. PMID:25342147

  11. Method and automated apparatus for detecting coliform organisms

    NASA Technical Reports Server (NTRS)

    Dill, W. P.; Taylor, R. E.; Jeffers, E. L. (Inventor)

    1980-01-01

    Method and automated apparatus are disclosed for determining the time of detection of metabolically produced hydrogen by coliform bacteria cultured in an electroanalytical cell from the time the cell is inoculated with the bacteria. The detection time data provides bacteria concentration values. The apparatus is sequenced and controlled by a digital computer to discharge a spent sample, clean and sterilize the culture cell, provide a bacteria nutrient into the cell, control the temperature of the nutrient, inoculate the nutrient with a bacteria sample, measures the electrical potential difference produced by the cell, and measures the time of detection from inoculation.

  12. Method and apparatus for detecting laminar flow separation and reattachment

    NASA Technical Reports Server (NTRS)

    Stack, John P. (Inventor); Mangalam, Sivaramakrishnan M. (Inventor)

    1990-01-01

    The invention is a method and apparatus for simultaneously detecting laminar separation and reattachment of a fluid stream such as an airstream from and to the upper surface of an airfoil by simultaneously sensing and comparing a plurality of output signals. Each signal represents the dynamic shear stress at one of an equal number of sensors spaced along a straight line on the surface of the airfoil that extends parallel to the airstream. The output signals are simultaneously compared to detect the sensors across which a reversal in phase of said output signal occurs, said detected sensors being in the region of laminar separation or reattachment.

  13. Machine Learning Methods for Attack Detection in the Smart Grid.

    PubMed

    Ozay, Mete; Esnaola, Inaki; Yarman Vural, Fatos Tunay; Kulkarni, Sanjeev R; Poor, H Vincent

    2016-08-01

    Attack detection problems in the smart grid are posed as statistical learning problems for different attack scenarios in which the measurements are observed in batch or online settings. In this approach, machine learning algorithms are used to classify measurements as being either secure or attacked. An attack detection framework is provided to exploit any available prior knowledge about the system and surmount constraints arising from the sparse structure of the problem in the proposed approach. Well-known batch and online learning algorithms (supervised and semisupervised) are employed with decision- and feature-level fusion to model the attack detection problem. The relationships between statistical and geometric properties of attack vectors employed in the attack scenarios and learning algorithms are analyzed to detect unobservable attacks using statistical learning methods. The proposed algorithms are examined on various IEEE test systems. Experimental analyses show that machine learning algorithms can detect attacks with performances higher than attack detection algorithms that employ state vector estimation methods in the proposed attack detection framework. PMID:25807571

  14. Pregabalin and Tranexamic Acid Evaluation by Two Simple and Sensitive Spectrophotometric Methods

    PubMed Central

    Sher, Nawab; Fatima, Nasreen; Perveen, Shahnaz; Siddiqui, Farhan Ahmed; Wafa Sial, Alisha

    2015-01-01

    This paper demonstrates colorimetric visible spectrophotometric quantification methods for amino acid, namely, tranexamic acid and pregabalin. Both drugs contain the amino group, and when they are reacted with 2,4-dinitrophenol and 2,4,6-trinitrophenol, they give rise to yellow colored complexes showing absorption maximum at 418 nm and 425 nm, respectively, based on the Lewis acid base reaction. Detailed optimization process and stoichiometric studies were conducted along with investigation of thermodynamic features, that is, association constant and standard free energy changes. The method was linear over the concentration range of 0.02–200 µgmL−1 with correlation coefficient of more than 0.9990 in all of the cases. Limit of detection was in range from 0.0041 to 0.0094 µgmL−1 and limit of quantification was in the range from 0.0137 to 0.0302 µgmL−1. Excellent recovery in Placebo spiked samples indicated that there is no interference from common excipients. The analytical methods under proposal were successfully applied to determine tranexamic acid and pregabalin in commercial products. t-test and F ratio were evaluated without noticeable difference between the proposed and reference methods. PMID:25873964

  15. Fluorescence probe for the convenient and sensitive detection of ascorbic acid

    PubMed Central

    Matsuoka, Yuta; Yamato, Mayumi; Yamada, Ken-ichi

    2016-01-01

    Ascorbic acid is an important antioxidant that plays an essential role in the biosynthesis of numerous bioactive substances. The detection of ascorbic acid has traditionally been achieved using high-performance liquid chromatography and absorption spectrophotometry assays. However, the development of fluorescence probes for this purpose is highly desired because they provide a much more convenient and highly sensitive technique for the detection of this material. OFF-ON-type fluorescent probes have been developed for the detection of non-fluorescent compounds. Photo-induced electron transfer and fluorescence resonance energy transfer are the two main fluorescence quenching mechanisms for the detection of ascorbic acid, and several fluorescence probes have been reported based on redox-responsive metals and quantum dots. Profluorescent nitroxide compounds have also been developed as non-metal organic fluorescence probes for ascorbic acid. These nitroxide systems have a stable unpaired electron and can therefore react with ascorbic acid and a strong fluorescence quencher. Furthermore, recent synthetic advances have allowed for the synthesis of α-substituted nitroxides with varying levels of reactivity towards ascorbic acid. In this review, we have discussed the design strategies used for the preparation of fluorescent probes for ascorbic acid, with particular emphasis on profluorescent nitroxides, which are unique radical-based redox-active fluorescent probes. PMID:26798193

  16. Stable dye-labelled oligonucleotide-nanoparticle conjugates for nucleic acid detection

    NASA Astrophysics Data System (ADS)

    Barrett, Lee; Dougan, Jennifer A.; Faulds, Karen; Graham, Duncan

    2011-08-01

    Metallic nanoparticles functionalized with oligonucleotides are used for a number of nucleic acid detection strategies. However, oligonucleotide-nanoparticle conjugates suffer from a lack of stability when exposed to certain conditions associated with DNA detection assays. In this study, we report the synthesis of thiol and thioctic acid-modified oligonucleotide gold nanoparticle (OGNs) conjugates functionalized with a dye label and varying spacer groups. The thioctic acid-modified conjugates exhibit increased stability when treated with dithiothreitol (DTT) compared to the more commonly used thiol modification. When the dye labelled oligonucleotide nanoparticle conjugates are exposed to the same conditions there is a pronounced increase in the stability for both thioctic acid and thiol modified sequences. These results open up the possibility of simply using a dye label to enhance the stability of oligonucleotide-nanoparticle conjugates in DNA detection assays where the enhanced stability of the conjugate system can be advantageous in more complex biological environments.

  17. Hydroxyapatite-phosphonoformic acid hybrid compounds prepared by hydrothermal method

    NASA Astrophysics Data System (ADS)

    Turki, Thouraya; Othmani, Masseoud; Bantignies, Jean-Louis; Bouzouita, Khaled

    2014-01-01

    Hydroxyapatites were prepared in the presence of different amounts of phosphonoformic acid (PFA) via the hydrothermal method. The obtained powders were characterized through chemical analysis, XRD, IR, 31P MAS-NMR, TEM, and TG-TDA. The XRD showed that the PFA did not affect the apatite composition. Indeed, only a reduction of the crystallite size was noted. After grafting of PFA, the IR spectroscopy revealed the appearance of new bands belonging to HPO42- and carboxylate groups of the apatite and organic moiety, respectively. Moreover, the 31P MAS-NMR spectra exhibited a peak with a low intensity assigned to the terminal phosphonate group of the organic moiety in addition to that of the apatite. Based on these results, a reaction mechanism involving the surface hydroxyl groups (tbnd Casbnd OH) of the apatite and the carboxyl group of the acid was proposed.

  18. Cascade enzymatic catalysis in poly(acrylic acid) brushes-nanospherical silica for glucose detection.

    PubMed

    Zhao, Yan; Wang, Ying; Zhang, Xiaobin; Kong, Rongmei; Xia, Lian; Qu, Fengli

    2016-08-01

    The ultrasensitive monitoring of glucose with a fast and accurate method is significant in potential therapeutics and optimizes protein biosynthesis. Incorporation of enzyme into matrix is considered as promising candidates for constructing highly sensitive glucose-responsive systems. In this study, three-dimensional poly(acrylic acid) brushes-nanospherical silica (PAA-nano silica) with high amplification capability and stability were used to covalently immobilize bienzymes for cascade enzymatic catalysis. The major advantages of PAA-nano silica-bienzyme co-incorporation is that the enzymes are proximity distribution, and such close confinement both minimized the diffusion of intermediates among the enzymes in the consecutive reaction and improve the utilization efficiency of enzymes, thereby enhancing the overall reaction efficiency and specificity. Thus, this present bienzymatic biosensor shows robust signal amplification and ultrasensitivity of glucose-responsive properties with a detection limit of 0.04μM. PMID:27216683

  19. Detection of Nucleic Acids with Graphene Nanopores: Ab Initio Characterization of a Novel Sequencing Device

    NASA Astrophysics Data System (ADS)

    Nelson, Tammie; Zhang, Bo; Prezhdo, Oleg

    2010-03-01

    We report an ab initio study of the interaction of two nucleobases, cytosine and adenine, with a novel graphene nanopore device for detecting the base sequence of a single-stranded nucleic acid (ssDNA or RNA). The nucleobases were inserted into a pore in a graphene nanoribbon, and the electrical current and conductance spectra were calculated as functions of voltage applied across the nanoribbon. The conductance spectra and charge densities were analyzed in the presence of each nucleobase in the graphene nanopore. The results indicate that, due to significant differences in the conductance spectra, the proposed device has adequate sensitivity to discriminate between different nucleotides. Moreover, we show that the nucleotide conductance spectra is not affected by its orientation inside the graphene nanopore. The proposed technique may be extremely useful for real applications in developing ultrafast, low cost DNA sequencing methods.

  20. Voltammetric detection of phenol at platinum-polytyramine composite electrodes in acidic media.

    PubMed

    Spătaru, Tanţa; Spătaru, Nicolae

    2010-08-15

    A composite obtained by depositing platinum nanoparticles in a polytyramine (PTy) matrix, electrochemically formed on graphite substrate, was used as electrode material for the investigation of phenol oxidation by use of anodic voltammetry. The results show that, in acidic media, the measurement of the oxidation peak current can be used as the basis for a simple, rapid method for the determination of phenol within a concentration range of 0.3-10 mM. A much better resistance to fouling during phenol detection (compared both with smooth platinum and with Pt nanoparticles on bare graphite substrate) is the main advantage of the Pt-PTy composite. These results are also noteworthy because they provide a basis for additional experiments devoted to obtaining new composite materials with improved performances for phenol anodic oxidation. PMID:20462693

  1. A divisive spectral method for network community detection

    NASA Astrophysics Data System (ADS)

    Cheng, Jianjun; Li, Longjie; Leng, Mingwei; Lu, Weiguo; Yao, Yukai; Chen, Xiaoyun

    2016-03-01

    Community detection is a fundamental problem in the domain of complex network analysis. It has received great attention, and many community detection methods have been proposed in the last decade. In this paper, we propose a divisive spectral method for identifying community structures from networks which utilizes a sparsification operation to pre-process the networks first, and then uses a repeated bisection spectral algorithm to partition the networks into communities. The sparsification operation makes the community boundaries clearer and sharper, so that the repeated spectral bisection algorithm extract high-quality community structures accurately from the sparsified networks. Experiments show that the combination of network sparsification and a spectral bisection algorithm is highly successful, the proposed method is more effective in detecting community structures from networks than the others.

  2. Comparison of formant detection methods used in speech processing applications

    NASA Astrophysics Data System (ADS)

    Belean, Bogdan

    2013-11-01

    The paper describes time frequency representations of speech signal together with the formant significance in speech processing applications. Speech formants can be used in emotion recognition, sex discrimination or diagnosing different neurological diseases. Taking into account the various applications of formant detection in speech signal, two methods for detecting formants are presented. First, the poles resulted after a complex analysis of LPC coefficients are used for formants detection. The second approach uses the Kalman filter for formant prediction along the speech signal. Results are presented for both approaches on real life speech spectrograms. A comparison regarding the features of the proposed methods is also performed, in order to establish which method is more suitable in case of different speech processing applications.

  3. Radial line method for rear-view mirror distortion detection

    NASA Astrophysics Data System (ADS)

    Rahmah, Fitri; Kusumawardhani, Apriani; Setijono, Heru; Hatta, Agus M.; Irwansyah, .

    2015-01-01

    An image of the object can be distorted due to a defect in a mirror. A rear-view mirror is an important component for the vehicle safety. One of standard parameters of the rear-view mirror is a distortion factor. This paper presents a radial line method for distortion detection of the rear-view mirror. The rear-view mirror was tested for the distortion detection by using a system consisting of a webcam sensor and an image-processing unit. In the image-processing unit, the captured image from the webcam were pre-processed by using smoothing and sharpening techniques and then a radial line method was used to define the distortion factor. It was demonstrated successfully that the radial line method could be used to define the distortion factor. This detection system is useful to be implemented such as in Indonesian's automotive component industry while the manual inspection still be used.

  4. Detection of Hb Constant Spring by a capillary electrophoresis method.

    PubMed

    Liao, Can; Zhou, Jian-Ying; Xie, Xing-Mei; Li, Jian; Li, Ru; Li, Dong-Zhi

    2010-01-01

    Hb Constant Spring [Hb CS; alpha142, Term-->Gln (TAA>CAA in alpha2)] is the most prevalent nondeletional alpha-thalassemia (alpha-thal) anomaly in southern China. In conjunction with alpha(0)-thal, it can cause severe Hb H (beta(4)) disease. The present study was done to evaluate the efficiency of two diagnostic methods in detecting Hb CS. Automated high performance liquid chromatography (HPLC) and Sebia Capillarys 2, a capillary electrophoresis method, were applied to blood samples from 21 individuals with Hb CS trait. Of the 21 cases, all (100%) were detected by capillary electrophoresis, whereas only 16 (76.2%) were detected by HPLC. We concluded that the Sebia Capillarys 2 is the preferred method for Hb CS screening. PMID:20353355

  5. A modified agar plate method for detection of Strongyloides stercoralis.

    PubMed

    Koga, K; Kasuya, S; Khamboonruang, C; Sukhavat, K; Ieda, M; Takatsuka, N; Kita, K; Ohtomo, H

    1991-10-01

    The agar plate method is a new technique with high detection rates for coprological diagnosis of human strongyloidiasis. This report details modifications of the technique and establishes a standardized procedure. We recommend that all plates should be carefully observed using a microscope because macroscopic observation can lead to false negative results. It is also advisable to pour formalin solution directly into microscopically positive dishes to collect worms by sedimentation. This procedure enables one to observe worms otherwise hidden. Sealing dishes with adhesive tape prevents larvae from crawling out of the dishes, eliminating any possibility in the reduction of detection rates, and greatly improves the safety conditions for the technician performing the procedure. We consider the agar plate method to be superior to the filter paper method in detecting Strongyloides, and we believe that it will eventually become the technique of choice. PMID:1951861

  6. Optical detection of concentrations for mixed acid: HF and HNO3

    NASA Astrophysics Data System (ADS)

    Kang, Gumin; Kim, Kyoungsik

    2009-02-01

    Mixed acid, which consist of HF and HNO3, is used as a good etchant for silicon dioxide in the wet etching and pickling process of stainless steel. The optical detection of concentration for such mixed acids is crucial to optimize and cut costs in the manufacturing process. Optical detection in the IR regime has been utilized to measure the concentration of the mixed acid for HF and HNO3, because that has several strong absorption peaks, which is contributed by vibrational mode of each acid molecular in this spectrum. In this research, we observed the concentrations of mixed acid to consist of HF and HNO3, as we measured the absorption intensity of OH- stretch and NO3 - stretch band by optical spectroscopy. The concentration range of HF over 1.5-3 wt% and that of HNO3 over 2-10 wt% were studied in room temperature.

  7. Detection of fatigue cracks by nondestructive testing methods

    NASA Technical Reports Server (NTRS)

    Anderson, R. T.; Delacy, T. J.; Stewart, R. C.

    1973-01-01

    The effectiveness was assessed of various NDT methods to detect small tight cracks by randomly introducing fatigue cracks into aluminum sheets. The study included optimizing NDT methods calibrating NDT equipment with fatigue cracked standards, and evaluating a number of cracked specimens by the optimized NDT methods. The evaluations were conducted by highly trained personnel, provided with detailed procedures, in order to minimize the effects of human variability. These personnel performed the NDT on the test specimens without knowledge of the flaw locations and reported on the flaws detected. The performance of these tests was measured by comparing the flaws detected against the flaws present. The principal NDT methods utilized were radiographic, ultrasonic, penetrant, and eddy current. Holographic interferometry, acoustic emission monitoring, and replication methods were also applied on a reduced number of specimens. Generally, the best performance was shown by eddy current, ultrasonic, penetrant and holographic tests. Etching provided no measurable improvement, while proof loading improved flaw detectability. Data are shown that quantify the performances of the NDT methods applied.

  8. Detection of formic acid in the cold, dark cloud L134N

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.; Minh, Y. C.; Friberg, P.; Kaifu, N.; Matthews, H. E.

    1990-01-01

    The detection of formic acid (HCOOH) in a cold dark interstellar cloud (L134N) is reported. The observed abundance of 3 x 10 to the 10th relative to H2 is between one and two orders of magnitude lower than that calculated by published ion-molecule models of dark-cloud chemistry, but is quite consistent with recent model revisions based on new reaction rates. Formic acid was not detected in the archetypical dark cloud TMC-1, and was tentatively detected in the region of massive star formation W51.

  9. Performance of two alternative methods for Listeria detection throughout Serro Minas cheese ripening.

    PubMed

    Mata, Gardênia Márcia Silva Campos; Martins, Evandro; Machado, Solimar Gonçalves; Pinto, Maximiliano Soares; de Carvalho, Antônio Fernandes; Vanetti, Maria Cristina Dantas

    2016-01-01

    The ability of pathogens to survive cheese ripening is a food-security concern. Therefore, this study aimed to evaluate the performance of two alternative methods of analysis of Listeria during the ripening of artisanal Minas cheese. These methods were tested and compared with the conventional method: Lateral Flow System™, in cheeses produced on laboratory scale using raw milk collected from different farms and inoculated with Listeria innocua; and VIDAS(®)-LMO, in cheese samples collected from different manufacturers in Serro, Minas Gerais, Brazil. These samples were also characterized in terms of lactic acid bacteria, coliforms and physical-chemical analysis. In the inoculated samples, L. innocua was detected by Lateral Flow System™ method with 33% false-negative and 68% accuracy results. L. innocua was only detected in the inoculated samples by the conventional method at 60-days of cheese ripening. L. monocytogenes was not detected by the conventional and the VIDAS(®)-LMO methods in cheese samples collected from different manufacturers, which impairs evaluating the performance of this alternative method. We concluded that the conventional method provided a better recovery of L. innocua throughout cheese ripening, being able to detect L. innocua at 60-day, aging period which is required by the current legislation. PMID:27268116

  10. Methods of use for sensor based fluid detection devices

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor)

    2001-01-01

    Methods of use and devices for detecting analyte in fluid. A system for detecting an analyte in a fluid is described comprising a substrate having a sensor comprising a first organic material and a second organic material where the sensor has a response to permeation by an analyte. A detector is operatively associated with the sensor. Further, a fluid delivery appliance is operatively associated with the sensor. The sensor device has information storage and processing equipment, which is operably connected with the device. This device compares a response from the detector with a stored ideal response to detect the presence of analyte. An integrated system for detecting an analyte in a fluid is also described where the sensing device, detector, information storage and processing device, and fluid delivery device are incorporated in a substrate. Methods for use for the above system are also described where the first organic material and a second organic material are sensed and the analyte is detected with a detector operatively associated with the sensor. The method provides for a device, which delivers fluid to the sensor and measures the response of the sensor with the detector. Further, the response is compared to a stored ideal response for the analyte to determine the presence of the analyte. In different embodiments, the fluid measured may be a gaseous fluid, a liquid, or a fluid extracted from a solid. Methods of fluid delivery for each embodiment are accordingly provided.

  11. An infrared spectroscopy method to detect ammonia in gastric juice.

    PubMed

    Giovannozzi, Andrea M; Pennecchi, Francesca; Muller, Paul; Balma Tivola, Paolo; Roncari, Silvia; Rossi, Andrea M

    2015-11-01

    Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations. PMID:26377936

  12. Reliability of nucleic acid amplification for detection of Mycobacterium tuberculosis: an international collaborative quality control study among 30 laboratories.

    PubMed Central

    Noordhoek, G T; van Embden, J D; Kolk, A H

    1996-01-01

    Nucleic acid amplification to detect Mycobacterium tuberculosis in clinical specimens is increasingly used as a laboratory tool for the diagnosis of tuberculosis. However, the specificity and sensitivity of these tests may be questioned, and no standardized reagents for quality control assessment are available. To estimate the performance of amplification tests for routine diagnosis, we initiated an interlaboratory study involving 30 laboratories in 18 countries. We prepared blinded panels of 20 sputum samples containing no, 100, or 1,000 mycobacterial cells. Each laboratory was asked to detect M. tuberculosis by their routine method of nucleic acid amplification. Only five laboratories correctly identified the presence or absence of mycobacterial DNA in all 20 samples. Seven laboratories detected mycobacterial DNA in all positive samples, and 13 laboratories correctly reported the absence of DNA in the negative samples. Lack of specificity was more of a problem than lack of sensitivity. Reliability was not found to be associated with the use of any particular method. Reliable detection of M. tuberculosis in clinical samples by nucleic acid amplification techniques is possible, but many laboratories do not use adequate quality controls. This study underlines the need for good laboratory practice and reference reagents to monitor the performance of the whole assay, including pretreatment of clinical samples. PMID:8880513

  13. Study on UPF Harmonic Current Detection Method Based on DSP

    NASA Astrophysics Data System (ADS)

    Zhao, H. J.; Pang, Y. F.; Qiu, Z. M.; Chen, M.

    2006-10-01

    Unity power factor (UPF) harmonic current detection method applied to active power filter (APF) is presented in this paper. The intention of this method is to make nonlinear loads and active power filter in parallel to be an equivalent resistance. So after compensation, source current is sinusoidal, and has the same shape of source voltage. Meanwhile, there is no harmonic in source current, and the power factor becomes one. The mathematic model of proposed method and the optimum project for equivalent low pass filter in measurement are presented. Finally, the proposed detection method applied to a shunt active power filter experimental prototype based on DSP TMS320F2812 is developed. Simulation and experiment results indicate the method is simple and easy to implement, and can obtain the real-time calculation of harmonic current exactly.

  14. Spectral anomaly methods for aerial detection using KUT nuisance rejection

    NASA Astrophysics Data System (ADS)

    Detwiler, R. S.; Pfund, D. M.; Myjak, M. J.; Kulisek, J. A.; Seifert, C. E.

    2015-06-01

    This work discusses the application and optimization of a spectral anomaly method for the real-time detection of gamma radiation sources from an aerial helicopter platform. Aerial detection presents several key challenges over ground-based detection. For one, larger and more rapid background fluctuations are typical due to higher speeds, larger field of view, and geographically induced background changes. As well, the possible large altitude or stand-off distance variations cause significant steps in background count rate as well as spectral changes due to increased gamma-ray scatter with detection at higher altitudes. The work here details the adaptation and optimization of the PNNL-developed algorithm Nuisance-Rejecting Spectral Comparison Ratios for Anomaly Detection (NSCRAD), a spectral anomaly method previously developed for ground-based applications, for an aerial platform. The algorithm has been optimized for two multi-detector systems; a NaI(Tl)-detector-based system and a CsI detector array. The optimization here details the adaptation of the spectral windows for a particular set of target sources to aerial detection and the tailoring for the specific detectors. As well, the methodology and results for background rejection methods optimized for the aerial gamma-ray detection using Potassium, Uranium and Thorium (KUT) nuisance rejection are shown. Results indicate that use of a realistic KUT nuisance rejection may eliminate metric rises due to background magnitude and spectral steps encountered in aerial detection due to altitude changes and geographically induced steps such as at land-water interfaces.

  15. Consistency-based ellipse detection method for complicated images

    NASA Astrophysics Data System (ADS)

    Zhang, Lijun; Huang, Xuexiang; Feng, Weichun; Liang, Shuli; Hu, Tianjian

    2016-05-01

    Accurate ellipse detection in complicated images is a challenging problem due to corruptions from image clutter, noise, or occlusion of other objects. To cope with this problem, an edge-following-based ellipse detection method is proposed which promotes the performances of the subprocesses based on consistency. The ellipse detector models edge connectivity by line segments and exploits inconsistent endpoints of the line segments to split the edge contours into smooth arcs. The smooth arcs are further refined with a novel arc refinement method which iteratively improves the consistency degree of the smooth arc. A two-phase arc integration method is developed to group disconnected elliptical arcs belonging to the same ellipse, and two constraints based on consistency are defined to increase the effectiveness and speed of the merging process. Finally, an efficient ellipse validation method is proposed to evaluate the saliency of the elliptic hypotheses. Detailed evaluation on synthetic images shows that our method outperforms other state-of-the-art ellipse detection methods in terms of effectiveness and speed. Additionally, we test our detector on three challenging real-world datasets. The F-measure score and execution time of results demonstrate that our method is effective and fast in complicated images. Therefore, the proposed method is suitable for practical applications.

  16. Development of a spatial method for weed detection and localization

    NASA Astrophysics Data System (ADS)

    Vioix, Jean-Baptiste; Douzals, Jean-Paul; Truchetet, Fréd. éric

    2004-02-01

    This paper presents an algorithm specifically developed for filtering low frequency signals. The application is related to weed detection into aerial images where crop lines are detected as repetitive structures. Theoretical bases of this work are presented first. Then, two methods are compared to select low frequency signals and their limitations are described. A decomposition based on wavelet packet is used to combine advantages of both methods. This algorithm allows a high selectivity of low frequency signals with an interesting computation time. At last, a complete algorithm for weed/crop classification is explained and a few results are shown.

  17. Preface to the Focus Issue: Chaos Detection Methods and Predictability

    SciTech Connect

    Gottwald, Georg A.; Skokos, Charalampos

    2014-06-01

    This Focus Issue presents a collection of papers originating from the workshop Methods of Chaos Detection and Predictability: Theory and Applications held at the Max Planck Institute for the Physics of Complex Systems in Dresden, June 17–21, 2013. The main aim of this interdisciplinary workshop was to review comprehensively the theory and numerical implementation of the existing methods of chaos detection and predictability, as well as to report recent applications of these techniques to different scientific fields. The collection of twelve papers in this Focus Issue represents the wide range of applications, spanning mathematics, physics, astronomy, particle accelerator physics, meteorology and medical research. This Preface surveys the papers of this Issue.

  18. Approach to evaluating leak detection methods in underground storage tanks

    NASA Astrophysics Data System (ADS)

    Starr, J.; Broscious, J.; Niaki, S.

    1986-10-01

    The detection and evaluation of leaks in underground storage tanks require a detailed knowledge of conditions both within the tank and in the nearby surroundings. The test apparatus, as constructed, enables data regarding these environmental conditions to be readily obtained and incorporated in a carefully structured test program that minimizes the amount of costly full-scale testing that would otherwise be required to evaluate volumetric leak detection methods for underground storage tanks. In addition, sufficient flexibility has been designed into the apparatus to enable additional evaluations of non-volumetric test methods to be conducted, and different types of tanks and products to be tested in a cost-effective manner.

  19. Proposal of Multiple Detection Method in Human Detection System using Terrestrial Digital TV Waves

    NASA Astrophysics Data System (ADS)

    Nishi, Masahiro; Shin, Koichi; Yoshida, Teruaki

    This paper newly proposes Multiple Detection (MD) method in the human detection system using terrestrial digital TV broadcasting waves. In the conventional human detection system using analog TV waves, human motion in a room can be detected by monitoring Received Signal Strength Indicator (RSSI) of the TV waves. The human detection system using TV waves works in the environments where there are no disturbances such as moving car and passing human outside the room. However, the digitalization of the terrestrial TV system deteriorates the detection performance of this system even in such environments. The radio propagation properties of the digital TV system are different from those of the analog one since the digital system is operated in the Single Frequency Network (SFN). In the SFN environment, there are some rooms under the condition that the received TV waves come from several broadcasting stations with same frequency. In such case, our measurement results indicate that the RSSI hardly fluctuates even under condition of human presence and the detection method only using RSSI has a possibility of overlooking the human motion. In the proposed MD method, not only RSSI but also Carrier to Noise Ratio (CNR) and Bit Error Rate (BER) are utilized for human detection. Today most digital TV tuners are capable of monitoring the quality of received signal, such as CNR and BER in addition to RSSI. In this paper, based on the practical measurements by using the digital TV tuners, we evaluate the fluctuation performances of RSSI, CNR and BER affected by human motion in a wooden detached house, and clarify that the MD method can effectively detect human motion even in the SFN environment.

  20. Zirconia based nucleic acid sensor for Mycobacterium tuberculosis detection

    NASA Astrophysics Data System (ADS)

    Das, Maumita; Sumana, Gajjala; Nagarajan, R.; Malhotra, B. D.

    2010-03-01

    Nanostructured zirconium oxide (ZrO2) film (particle size˜35 nm), electrochemically deposited onto gold(Au) surface, has been used to immobilize 21-mer oligonucleotide probe (ssDNA) specific to Mycobacterium tuberculosis by utilizing affinity between oxygen atom of phosphoric group and zirconium to fabricate DNA biosensor. This DNA-ZrO2/Au bioelectrode, characterized using x-ray diffraction, Fourier transform infrared spectroscopy, cyclic voltammetry, and scanning electron microscopy techniques, can be used for early and rapid diagnosis of M. tuberculosis with detection limit of 0.065 ng/μL within 60s.