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Sample records for sandwich elisa electronic

  1. Hyperglucagonaemia analysed by glucagon sandwich ELISA

    DEFF Research Database (Denmark)

    Albrechtsen, Nicolai Jacob Wewer; Hartmann, Bolette; Veedfald, Simon

    2014-01-01

    characterised. The specific determination of fully processed, intact glucagon requires a 'sandwich' assay employing a combination of antibodies directed against both N- and C-termini. We compared a novel assay for intact glucagon with a highly sensitive C-terminal RIA (hitherto considered specific) to determine...... the extent to which the hyperglucagonaemia measured in clinical samples was caused by authentic glucagon. METHODS: We examined the performance of three commercial glucagon 'sandwich' ELISAs. The ELISA with the best overall performance was selected to compare glucagon measurements in clinical samples...

  2. Evaluation and selection of indirect ELISA and sandwich ELISA kits for anti-HCV detection

    Directory of Open Access Journals (Sweden)

    LI Yongzhen

    2014-10-01

    Full Text Available ObjectiveTo compare the sensitivity and specificity between indirect enzyme-linked immunosorbent assay (ELISA and double-antibody sandwich ELISA kits produced in China and to select the best ELISA kit. MethodsSamples for evaluation included 60 serum plates and 40 serum samples positive or weakly positive for antibody to hepatitis C virus (anti-HCV which were confirmed by recombinant immunoblot assay. These samples were tested with a sandwich ELISA kit and three indirect ELISA kits, all of which were produced in China. Comparison between ELISA kits was made by paired chi-square test; comparison of false negative rate was made by R×C contingency table test. ResultsThe sensitivities of three indirect ELISA kits and a sandwich ELISA kit were 90.2%, 78.0%, 95.1%, and 97.6%, respectively, and the specificities were 78.1%, 72.6%, 94.1%, and 100%, respectively. The sandwich ELISA kit had a 4-8 times higher sensitivity than indirect ELISA kits. The R×C contingency table test revealed significant differences in false negative rate between ELISA kits and combinations of ELISA kits (χ2=29.898, P<0.05. ConclusionSandwich ELISA kit has higher sensitivity and specificity than indirect ELISA kits. Combined use of sandwich ELISA and indirect ELISA kits can significantly reduce the false negative rate and effectively prevent missed anti-HCV detection.

  3. A sandwich ELISA to detect VHSV and IPNV in turbot

    OpenAIRE

    Vázquez-Brañas, M. (Manuel); Coll-Morales, J. (Julio); Estepa, A

    1994-01-01

    Abstract: The recent demonstration that reared turbot (Scophthalmus maximus L) is a natural host for salmonid rhabdoviruses has made their rapid detection relevant to these fish species. A unique protocol to select and use non-competitive monoclonal antibodies (Mabs) for two high-sensitivity sandwich ELISAs has been developed to detect both infectious pancreatic necrosis virus (IPNV) and viral haemorrhagic septicaemia virus (VHSV) in turbot kidney extracts to assess the possibility of using t...

  4. Detection of Penicillinase in Milk by Sandwich ELISA Based Polyclonal and Monoclonal Antibody.

    Science.gov (United States)

    Zhao, Yinli; Li, Guoxi

    2016-01-01

    A sandwich ELISA has been developed using polyclonal and monoclonal antibody for the determination of penicillinase in milk. For this purpose, specific polyclonal and monoclonal antibodies against penicillinase were generated and characterized. Using penicillinase standards prepared from 1-128 ng/mL, the method indicated that the detection limit of the sandwich ELISA, as measured in an ELISA plate reader, was as low as 0.86 ng/mL of penicillinase. For determine the accuracy, raw milk containing 2, 8, 32, and 64 ng/mL of penicillinase were tested by sandwich ELISA. Recoveries were from 93-97.5%, and the coefficient of variation [CV (%)] were from 5.55-8.38%. For interassay reproducibility, recoveries were from 89.5-95.1%, the coefficient of variation [CV (%)] were from 5.26-9.58%. This sandwich ELISA provides a useful screening method for quantitative detection of penicillinase in milk.

  5. Development of indirect sandwich ELISA for determination of excretory-secretory antigens of Fasciola hepatica

    Directory of Open Access Journals (Sweden)

    Libertad Alzamora-Gonzales

    2016-05-01

    Full Text Available Fasciolosis is a cosmopolitan parasitosis medical-veterinary importance caused by Fasciola hepatica, which affects sheep, goats and cattle; and it affects man accidentally causing an epidemic-endemic infection difficult to diagnose. The aim was to develop an indirect sandwich ELISA with 3 antibodies for detecting excretory-secretory antigens of Fasciola hepatica (ESFh. For the development of indirect sandwich ELISA were used, as capture antibody, mouse polyclonal antibodies anti ESFh and polyclonal antibodies rabbit anti-ESFh as detection antibody, at the concentrations of 10 and 5 µg/mL respectively. The conjugate used was mouse monoclonal anti- total immunoglobulins rabbit linked to peroxidase (1/1000. Were analized 31 sheep fecal samples, and the results were compared with those obtained by direct coproparasitological examination (DC and counterimmunoelectrophoresis (CIEP. The detection limit obtained for indirect sandwich ELISA was 100 ng/mL. The test had a 100% sensitivity, 96.6% specificity, positive and negative predictive values of 50% and 96.6% respectively, in relation to DC test. Comparing with CIEP the specificity obtained for indirect sandwich ELISA was 93.5% and a negative predictive value of 100%. We concluded that indirect sandwich ELISA designed is able to detect metabolic antigens in ovine feces samples and can be used for Fasciola hepatica diagnosis.

  6. Qualitative and quantitative detection of T7 bacteriophages using paper based sandwich ELISA.

    Science.gov (United States)

    Khan, Mohidus Samad; Pande, Tripti; van de Ven, Theo G M

    2015-08-01

    Viruses cause many infectious diseases and consequently epidemic health threats. Paper based diagnostics and filters can offer attractive options for detecting and deactivating pathogens. However, due to their infectious characteristics, virus detection using paper diagnostics is more challenging compared to the detection of bacteria, enzymes, DNA or antigens. The major objective of this study was to prepare reliable, degradable and low cost paper diagnostics to detect viruses, without using sophisticated optical or microfluidic analytical instruments. T7 bacteriophage was used as a model virus. A paper based sandwich ELISA technique was developed to detect and quantify the T7 phages in solution. The paper based sandwich ELISA detected T7 phage concentrations as low as 100 pfu/mL to as high as 10(9) pfu/mL. The compatibility of paper based sandwich ELISA with the conventional titre count was tested using T7 phage solutions of unknown concentrations. The paper based sandwich ELISA technique is faster and economical compared to the traditional detection techniques. Therefore, with proper calibration and right reagents, and by following the biosafety regulations, the paper based technique can be said to be compatible and economical to the sophisticated laboratory diagnostic techniques applied to detect pathogenic viruses and other microorganisms.

  7. Perbedaan Metode ELISA Sandwich A dan B dalam Deteksi Antigen Membran Toxoplasma gondii

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    ADI PRAYITNO

    2004-11-01

    Full Text Available Spreading of toxoplasmosis to fetus can by placenta, so it caused theabortion, born dead or congenital defect. To diagnosis this disease for fixed the acute infection must get the significant increasing of IgG by the soft fee. The objections of this study are to know the difference between ELISA Sandwich A and B in detecting of membrane antigen of Toxoplasma gondii (T. gondii in placenta tissue of pregnant women three-semester I and II with spontaneous abortion in Surakarta. One hundred serum and placenta tissue samples of pregnant women three-semester I and II with spontaneous abortion are got from dr. Muwardi Hospital. IgM anti Toxo from serum was examined by Toxo ISAGA Kit and IgG anti Toxo by Toxo Screen DA Kit. Detecting of membrane antigen of T. goodie from placenta tissue were done by ELISA Sandwich A and B. The result of this experiment showed that 33% were positive IBM and or Gig anti Toxo. Detection of membrane antigen toward 33 samples with positive Toxo (IgG positive was highly significant different between ELISA Sandwich A (3% positive toward ELISA Sandwich B (72.7% positive.

  8. A double-sandwich ELISA for identification of monoclonal antibodies suitable for sandwich immunoassays

    Science.gov (United States)

    The sandwich immunoassay (sIA) is an invaluable technique for concentrating, detecting, and quantifying target antigens. The two critical components required are a capture antibody and a detection antibody, each binding a different epitope on the target antigen. The specific antibodies incorporated...

  9. An ultra-specific and sensitive sandwich ELISA for imatinib using two anti-imatinib antibodies.

    Science.gov (United States)

    Saita, Tetsuya; Yamamoto, Yuta; Hosoya, Kazuhisa; Yamamoto, Yutaro; Kimura, Sakiko; Narisawa, Yutaka; Shin, Masashi

    2017-05-29

    The development of an immunoassay for a low-molecular-weight drug first requires the identification of specific antibodies that do not cross-react with the drug's metabolites. If two antibodies can simultaneously recognize the entire structure of the drug, we can then utilize them to establish an ultra-specific sandwich ELISA, free from interference due to the metabolic products of the drug. This paper reports an ultra-specific and sensitive sandwich ELISA for determination of the tyrosine kinase inhibitor imatinib using two anti-imatinib antibodies. The anti-imatinib antibodies were obtained by two partial structures of imatinib as haptens (2-(5-amino-2-methylanilino)-4-(3-pyridyl)pyrimidine and 4-{(4-methyl-1-piperazinyl)-methyl}-benzoate). Under optimized conditions, this sandwich ELISA shows a linear detection range from 64 pg mL(-1) to 8 ng mL(-1), and a limit of detection of approximately 64 pg mL(-1) for 100-μL samples. The ELISA is specific to imatinib and while there was no cross-reactivity with the major metabolite N-desmethyl-imatinib, slight cross-reactivity was found with metabolite pyridine-N-oxide-imatinib. This assay demonstrated significantly lower cross-reactivity with metabolites than competitive ELISAs. Using this assay, drug levels were easily measured in rat blood after oral administration of imatinib via a single dose of 30 mg kg(-1) or 100 mg kg(-1). The levels in rat serum measured by this ELISA were comparable with those measured by HPLC, and there was a strong correlation between the values determined by the two methods (y = 0.983x + 0.081, R(2) = 0.948). Thus, we have successfully developed the first specific and sensitive sandwich ELISA for imatinib using two anti-imatinib antibodies. This sandwich ELISA will be a valuable tool for therapeutic drug monitoring and pharmacokinetic studies of imatinib. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Monoclonal antibody-based sandwich ELISA for the detection of staphylococcal enterotoxin A.

    Science.gov (United States)

    Kuang, Hua; Wang, Wenbing; Xu, Liguang; Ma, Wei; Liu, Liqiang; Wang, Libing; Xu, Chuanlai

    2013-04-19

    A sensitive and specific monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (ELISA) was established and validated for the detection of staphylococcal enterotoxin A (SEA). After routine fusion and selection, 10 monoclonal antibodies showed high affinity for SEA. An optimal pair for sandwich ELISA was selected by pairwise interaction analysis. After optimization, the limit of detection (LOD) and linear dynamic range of the method were established, and were found to be 0.0282 ng/mL and 0.06-2 ng/mL, respectively. The recovery in pure milk ranged from 82.67% to 111.95% and the intra- and inter-assay coefficients of variation ranged from 3.16% to 6.05% and from 5.16% to 10.79%, respectively. Cross-reactivity with staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC), staphylococcal enterotoxin D (SED), and staphylococcal enterotoxin E (SEE) in this method were insignificant. These results indicate that the sandwich ELISA method developed in our study is effective for routine identification of SEA in food samples.

  11. Development of monoclonal antibody-based sandwich ELISA for detection of dextran.

    Science.gov (United States)

    Wang, Sheng-Yu; Li, Zhe; Wang, Xian-Jiang; Lv, Sha; Yang, Yun; Zeng, Lian-Qiang; Luo, Fang-Hong; Yan, Jiang-Hua; Liang, Da-Feng

    2014-10-01

    Dextran as anti-nutritional factor is usually a result of bacteria activity and has associated serial problems during the process stream in the sugar industry and in medical therapy. A sensitive method is expected to detect dextran quantitatively. Here we generated four monoclonal antibodies (MAbs) against dextran using dextran T40 conjugated with bovine serum albumin (BSA) as immunogen in our lab following hybridoma protocol. Through pairwise, an MAb named D24 was determined to be conjugated with horseradish peroxidase (HRP) and was used in the establishment of a sensitive sandwich enzyme-linked immunosorbent assay (ELISA) method for determination of dextran, in which MAb D9 was chosen as a capture antibody. The detection limit and working scope of the developed sandwich ELISA method were 3.9 ng/mL and 7.8-500 ng/mL with a correlation coefficient of 0.9909. In addition, the cross-reaction assay demonstrated that the method possessed high specificity with no significant cross-reaction with dextran-related substances, and the recovery rate ranged from 96.35 to 102.00%, with coefficient of variation ranging from 1.58 to 6.94%. These results indicated that we developed a detection system of MAb-based sandwich ELISA to measure dextran and this system should be a potential tool to determine dextran levels.

  12. Development of a sandwich Dot-ELISA for detecting bovine viral diarrhea virus antigen with E2 recombinant protein

    Institute of Scientific and Technical Information of China (English)

    Yuelan ZHAO; Yuzhu ZUO; Lei ZHANG; Jinghui FAN; Hanchun YANG; Jianhua QIN

    2009-01-01

    The IgG antibodies of rabbit anti-E2 protein of the bovine viral diarrhea virus were prepared by a general method from high efficiency serum immunized by E2 recombinant protein antigen expressed in E. coli prokaryotic expression system and were labeled to make enzymelabeled antibody with the method of NaIO4. A sandwich Dot enzyme-linked immunosorbent assay (Dot-ELISA) for the detection of BVDV was developed. The optimal reaction conditions of Dot-ELISAwere determined. The results show that optimal coating antibody was 300 μg·mL-1, the working concentration of HRP-labeled antibody was 1:50. The optimal blocking reagent and time were 5% bovine serum and 45 rain. The minimum detection of the content of antigen reached 1.35μg·mL-1. Compared with the routine IDEXX ELISA test kit with the whole virus, its specificity, sensitivity and coincidence rate were 90.48%, 96.55% and 95.24%, respectively. Compared with the sandwich Dot-ELISA with the negative staining electron microscope and RT-PCR, the coincidence rates were 90.9% and 93.1%, respectively. In addition, Bovine viral diarrhea virus (BVDV) antigen of 178 samples collected from cow farms in the Hebei Province, China, were detected by the developed Dot-ELISA and the IDEXX BVDV antigen Test Kit simultaneously, BVDV antigen positive rate was 39.89%-41.01%. The result of detecting clinical samples demonstrated that the established method showed its specificity, sensitivity and repeatability, whereas the results were easily interpreted without an ELISA reader.

  13. Sandwich enzyme-linked immunosorbent assay (ELISA) for the detection of lupine residues in foods.

    Science.gov (United States)

    Kaw, C H; Hefle, S L; Taylor, S L

    2008-10-01

    Lupine has been increasingly used in food applications due to its high nutritional value and excellent functional properties. However, lupine provokes allergic reactions in susceptible individuals. The presence of undeclared lupine residues in foods can pose a serious health risk to lupine-allergic individuals. Therefore, the objective of this research was to develop a sandwich-type ELISA for the detection of lupine residues in foods. Lupine flour derived from Lupinus albus was used to immunize 3 rabbits and a sheep. Pooled lupine-specific antibodies were partially purified from the sera by ammonium sulfate precipitation. A sandwich lupine ELISA with a limit of quantification (LOQ) of 1 ppm was developed by utilizing the rabbit antisera as the capture reagent and the sheep antiserum as the detector reagent. The binding of the antigen-antibody complex was visualized by the addition of commercial rabbit antisheep IgG antibody labeled with alkaline phosphatase with subsequent addition of p-nitrophenyl phosphate substrate to produce a colored product for quantification. Minor cross-reactivity was observed with soy (Glycine max) and black bean (Castanospermum australe). The performance of the lupine ELISA was evaluated in reference food standards (beef frankfurter and apple cinnamon muffin) and laboratory-prepared cooked frankfurters and corn muffins. The mean percent recovery for lupine spiked-frankfurters and corn muffins were 108.4%+/- 8.8% and 103.1%+/- 11.5%, respectively. The sandwich-type lupine ELISA developed in this study provides food manufacturers and regulatory agencies with an effective analytical tool to detect and quantify lupine residues in processed foods.

  14. Sandwich ELISA for quantitative detection of human collagen prolyl 4-hydroxylase

    Directory of Open Access Journals (Sweden)

    Myllyharju Johanna

    2010-06-01

    Full Text Available Abstract Background We describe a method for specific, quantitative and quick detection of human collagen prolyl 4-hydroxylase (C-P4H, the key enzyme for collagen prolyl-4 hydroxylation, in crude samples based on a sandwich ELISA principle. The method is relevant to active C-P4H level monitoring during recombinant C-P4H and collagen production in different expression systems. The assay proves to be specific for the active C-P4H α2β2 tetramer due to the use of antibodies against its both subunits. Thus in keeping with the method C-P4H is captured by coupled to an anti-α subunit antibody magnetic beads and an anti-β subunit antibody binds to the PDI/β subunit of the protein. Then the following holoenzyme detection is accomplished by a goat anti-rabbit IgG labeled with alkaline phosphatase which AP catalyzes the reaction of a substrate transformation with fluorescent signal generation. Results We applied an experimental design approach for the optimization of the antibody concentrations used in the sandwich ELISA. The assay sensitivity was 0.1 ng of C-P4H. The method was utilized for the analysis of C-P4H accumulation in crude cell extracts of E. coli overexpressing C-P4H. The sandwich ELISA signals obtained demonstrated a very good correlation with the detected protein activity levels measured with the standard radioactive assay. The developed assay was applied to optimize C-P4H production in E. coli Origami in a system where the C-P4H subunits expression acted under control by different promoters. The experiments performed in a shake flask fed-batch system (EnBase® verified earlier observations that cell density and oxygen supply are critical factors for the use of the inducer anhydrotetracycline and thus for the soluble C-P4H yield. Conclusions Here we show an example of sandwich ELISA usage for quantifying multimeric proteins. The method was developed for monitoring the amount of recombinant C-P4H tetramer in crude E. coli extracts. Due

  15. Development of a sandwich ELISA for quantification of immunoglobulin G in mink blood

    DEFF Research Database (Denmark)

    Mathiesen, Ronja; Chriél, Mariann; Struve, T.;

    A major concern amongst the Danish mink farmers is the incidence of the syndrome pre-weaning diarrhea. The syndrome causes major management issues and decreases the welfare of the mink and increases mortality in the pre-weaning period. The etiology of the syndrome is considered multifactorial...... as a specific cause is not fully established or understood. Adding to an increased risk of developing pre-weaning diarrhea is the fact that the mink kits are born with very low levels of circulating immunoglobulins. Rapid achievement of high levels of immunoglobulins in the bloodstream is essential for the kits...... early immunity and thus their resistance against pathogenic agents found in the environment. This study describes a sandwich ELISA for quantification of the concentration of total immunoglobulin G in mink blood. The ELISA was validated with serum samples from females (n=8) and their kits (litters of 4...

  16. Development of Double Antibody Sandwich ELISA for Detection of Duck or Goose Flavivirus

    Institute of Scientific and Technical Information of China (English)

    NIU Hui-min; LI Xiang-rui; LI Yin; HUANG Xin-mei; HAN Kai-kai; LIU Yu-zhuo; ZHAO Dong-min; ZHANG Jing-feng; LIU Fei; LI Tong-tong; ZHOU Xiao-bo

    2013-01-01

    In order to establish double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal antibody against the E protein of flavivirus strain JS804 in geese were used as the capture antibody and detection antibody, respectively. The optimal dilution of the capture antibody and detecting antibody capable of detecting the flavivirus strain JS804 in geese were 1:3 200 and 1:160 in the check-board titration, respectively. The reaction time of sample was 1 h, and the optimal working dilution of HRP-labeled goat-anti-mouse IgG was 1:10 000. The positive standard value was 0.247 (OD450 nm). The geese flavivirus could be detected at a minimal concentration of 1.875μg mL-1. The ELISA had no cross-reaction with Newcastle disease virus (NDV), Avian influenza virus (AIV), Infectious bronchitis virus (IBV), Infectious bursal disease virus (IBDV), Duck hepatitis virus (DHV), and Gosling plague virus (GPV). Twenty clinical samples were detected by the DAS-ELISA and RT-PCR respectively, with the agreement rate of 75%. The results revealed that the DAS-ELISA possessed favorable specificity and higher sensitivity, indicating a suitable method for rapid detection of the duck or goose flavivirus.

  17. Development of a monoclonal sandwich ELISA for direct detection of bluetongue virus 8 in infected animals.

    Science.gov (United States)

    Ten Haaf, Andre; Kohl, Johannes; Pscherer, Sibylle; Hamann, Hans-Peter; Eskens, Hans Ulrich; Bastian, Max; Gattenlöhner, Stefan; Tur, Mehmet Kemal

    2017-05-01

    Bluetongue is an infectious viral disease which can cause mortality in affected ruminants, and tremendous economic damage via impacts upon fertility, milk production and the quality of wool. The disease is caused by bluetongue virus (BTV) which is transmitted by species of Culicoides biting midge. Rapid detection of BTV is required to contain disease outbreaks and reduce economic losses. The purpose of this study was to develop a monoclonal sandwich ELISA for direct detection of BTV in infected animals. Phage display technology was used to isolate BTV specific antibody fragments by applying the human scFv Tomlinson antibody libraries directly on purified BTV-8 particles. Three unique BTV-8 specific human antibody fragments were isolated which were able to detect purified BTV particles and also BTV in serum of an infected sheep. A combination of a human/mouse scFv-Fc chimeric fusion protein and a human Fab fragment in a sandwich ELISA format was able to detect BTV specifically with a limit of detection (LOD) of 10(4) infectious virus particles, as determined by tissue culture titration. This approach provided pilot data towards the development of a novel diagnostic test that might be used for direct detection of BTV-8 particles. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Quantitative sandwich ELISA for the determination of lupine (Lupinus spp.) in foods.

    Science.gov (United States)

    Holden, Lise; Faeste, Christiane K; Egaas, Eliann

    2005-07-27

    The use of lupine in foods has increased considerably during the past decade, reflected by a corresponding increase in reported lupine-induced allergic incidents. Lupine allergy may arise either by primary sensitization or by clinical cross-reactivity in peanut-allergic persons. Detection of lupine proteins in food has previously been based on the use of patient serum. A novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of lupine in processed foods was developed, using a polyclonal rabbit antilupine capture antibody and a biotinylated conjugate of the same antibody for detection. The antibody was highly specific for lupine, apart from minor cross-reactivities to other legumes. The assay had a detection limit of 1 mug/g and was successfully used to quantify lupine protein in various food matrixes. Recoveries ranged from 60 to 116%, while the intra-and interassay coefficients of variation were <6% and <21%, respectively.

  19. Quantitative sandwich ELISA for determination of traces of hazelnut (Corylus avellana) protein in complex food matrixes.

    Science.gov (United States)

    Holzhauser, T; Vieths, S

    1999-10-01

    A hazelnut-specific sandwich-type ELISA based on polyclonal antisera was developed for detection of hidden hazelnut protein residues in complex food matrixes. In the absence of a food matrix, extractable protein from different native and toasted hazelnuts was detected at rates of 94 +/- 13 and 96 +/- 7% applying standards prepared from native and toasted hazelnuts, respectively. From complex food matrixes, 0.001-10% of hazelnut was recovered between 67 and 132%, in average by 106 +/- 17%. Depending on the food matrix, hazelnut protein could be detected down to the ppb (ng/g) level. Intraassay precision was hazelnut >/= 0.001% and interassay precision was hazelnut >/= 0.01%. In 12 of 28 commercial food products without labeling or declaration of hazelnut components, between 2 and 421 ppm of hazelnut protein was detected, demonstrating a remarkable presence of potentially allergenic hazelnut protein "hidden" in commercial food products.

  20. Detection of potentially allergenic hazelnut (Corylus avellana) residues in food: a comparative study with DNA PCR-ELISA and protein sandwich-ELISA.

    Science.gov (United States)

    Holzhauser, Thomas; Stephan, Oliver; Vieths, Stefan

    2002-10-09

    Allergen detection is of increasing interest for food labeling purposes. A comparative study with a commercial hazelnut-specific PCR-ELISA and a sandwich-type ELISA detecting hazelnut protein was performed to investigate to what extent immunochemical and DNA-based techniques would correlate in the detection of trace amounts of potentially allergenic hazelnut residues. Both methods were highly sensitive and allowed the detection of even hazelnut in complex food matrixes. The protein-ELISA was highly specific for hazelnut. However, some foods could lead to false-positive results at the 10 ppm level. The PCR-ELISA did not show any cross-reactions with non-hazelnut foods, thus reducing the probability of having false positives at the trace level. Forty-one commercial food products with and without hazelnut components on their labels were analyzed for the presence of hazelnut. Of the 27 products in which hazelnut components were detected, two samples were not identified by the protein-ELISA, and only one sample, namely one white chocolate having hazelnut protein, was not detected by PCR-ELISA. The good correlation of the results of PCR-ELISA and protein-ELISA suggested that both PCR-based and immunochemical techniques are suitable for reliable detection of potentially allergenic hazelnut residues in foods at the trace level.

  1. A sandwich ELISA for the conformation-specific quantification of the activated form of human Bax.

    Science.gov (United States)

    Teijido, Oscar; Ganesan, Yogesh Tengarai; Llanos, Raul; Peton, Ashley; Urtecho, Jean-Baptiste; Soprani, Adauri; Villamayor, Aimee; Antonsson, Bruno; Manon, Stéphen; Dejean, Laurent

    2016-03-15

    Bcl-2 family proteins are critical regulators of mitochondrial outer membrane permeabilization (MOMP), which represents the point of no return of apoptotic cell death. The exposure of the Bax N-terminus at the mitochondria reflects Bax activation; and this activated configuration of the Bax protein is associated with MOMP. N-terminal exposure can be detected using specific monoclonal and/or polyclonal antibodies, and the onset of activated Bax has extensively been used as an early marker of apoptosis. The protocols of immunoprecipitation and/or immunocytochemistry commonly used to detect activated Bax are long and tedious, and allow semiquantification of the antigen at best. The sandwich ELISA protocol we developed has a 5 ng/mL detection limit and is highly specific for the activated conformation of Bax. This ELISA allows a rapid quantification of activated human Bax in whole cells and isolated mitochondria protein extracts. These properties grant this assay the potential to further clarify the prognostic and diagnostic value of activated Bax in disorders associated with deregulated apoptotic pathways such as degenerative diseases or cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Development of a double-monoclonal antibody sandwich ELISA: Tool for chicken interferon-γ detection ex vivo

    Science.gov (United States)

    Dai, Hua; Xu, Zheng-zhong; Wang, Meiling; Chen, Jun-hua; Chen, Xiang; Pan, Zhi-ming; Jiao, Xin-an

    2016-01-01

    The aim of the present work was to develop reagents to set up a chicken interferon-γ (ChIFN-γ) assay. Four monoclonal antibodies (mAbs) specific for ChIFN-γ were generated to establish sandwich ELISA based on 2 different mAbs. To improve the detection sensitivity of ChIFN-γ, a double-monoclonal antibody sandwich ELISA was developed using mAb 3E5 as capture antibody and biotinylated mAb 3E3 as a detection reagent. The results revealed that this ELISA has high sensitivity, allowing for the detection of 125 to 500 pg/mL of recombinant ChIFN-γ, and also has an excellent capacity for detecting native ChIFN-γ. This ELISA was then used to detect ChIFN-γ level in chickens immunized with a Newcastle disease virus (NDV) vaccine, the immunized chicken splenocytes were stimulated by NDV F protein as recall antigen. From our results, it appears that the sensitivity range of this sandwich ELISA test is adequate to measure the ex vivo release of ChIFN-γ. PMID:27127340

  3. Electronically asymmetric bis(porphyrin) sandwich complexes

    Energy Technology Data Exchange (ETDEWEB)

    Girolami, G.S.; Gorlin, P.A.; Suslick, K.S. [Univ. of Illinois, Urbana, IL (United States)

    1994-02-16

    Bis(porphyrin)metal(IV) complexes (M(porph){sub 2}) have been extensively studies in recent years due to their structural, chemical, and spectroscopic similarity to the {open_quotes}special pair{close_quotes} found in the reaction center of photosynthetic bacteria. Strong interactions arise in the bis(porphyrin) complexes due to the short inter-porphyrin separation (< 3 {angstrom}), which results in properties not seen in mono(porphyrin) analogs. For example, the bis(porphyrin) complexes are considerably easier to oxidize than analogous mono(porphyrin) species, and the M(porph){sub 2{sup n+}} cations (n = 1,2) exhibit near-IR absorptions not found in simple mono(porphyrin)cations. As part of the authors continuing effort to understand the factors that govern the electronic structures of bis(porphyrin) supermolecules, the authors now describe the synthesis of a series of zirconium sandwich complexes. Introduction of electron-withdrawing or -donating groups on the {beta}-pyrrole position considerably affects the electronic properties of these molecules without altering their steric parameters. Thus, peripheral substitution allows modification of the inter-porphyrin {pi} interactions while keeping the inter-porphyrin separation constant. Previous studies have changed the identity of the central metal, but the electronic structure and the interplanar distance could not be varied independently.

  4. Validation and comparison of a sandwich ELISA, two competitive ELISAs and a real-time PCR method for the detection of lupine in food.

    Science.gov (United States)

    Ecker, Christina; Ertl, Anna; Pulverer, Walter; Nemes, Albert; Szekely, Pal; Petrasch, Angelika; Linsberger-Martin, Gertrud; Cichna-Markl, Margit

    2013-11-01

    Methods applied in food allergen analysis should be specific, sensitive and applicable to both raw and highly processed foods. The performance of the most commonly used methods, ELISA and real-time PCR, may, however, be influenced by food processing steps, e.g., heat treatment. The present study compares the applicability of four in-house developed methods, one sandwich ELISA, two competitive ELISAs and a real-time PCR method, for the detection of lupine in four different food matrices, comprising bread, biscuits, rice patties and noodles. In order to investigate the influence of food processing on the detectability, not only the heat treated model foods but also the corresponding doughs were analysed. The sandwich ELISA proved to be the most sensitive method. The LOD was found to be 10 ppm lupine, independent from the food matrix and independent if the dough or the heat treated food was analysed. In addition, the methods were applied to the analysis of commercial foodstuffs differing in their labelling. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. A sandwich ELISA for measurement of the primary glucagon-like peptide-1 metabolite.

    Science.gov (United States)

    Wewer Albrechtsen, Nicolai J; Asmar, Ali; Jensen, Frederik; Törang, Signe; Simonsen, Lene; Kuhre, Rune E; Asmar, Meena; Veedfald, Simon; Plamboeck, Astrid; Knop, Filip K; Vilsbøll, Tina; Madsbad, Sten; Nauck, Michael A; Deacon, Carolyn F; Bülow, Jens; Holst, Jens J; Hartmann, Bolette

    2017-09-01

    Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted from the gastrointestinal tract. It is best known for its glucose-dependent insulinotropic effects. GLP-1 is secreted in its intact (active) form (7-36NH2) but is rapidly degraded by the dipeptidyl peptidase 4 (DPP-4) enzyme, converting >90% to the primary metabolite (9-36NH2) before reaching the targets via the circulation. Although originally thought to be inactive or antagonistic, GLP-1 9-36NH2 may have independent actions, and it is therefore relevant to be able to measure it. Because reliable assays were not available, we developed a sandwich ELISA recognizing both GLP-1 9-36NH2 and nonamidated GLP-1 9-37. The ELISA was validated using analytical assay validation guidelines and by comparing it to a subtraction-based method, hitherto employed for estimation of GLP-1 9-36NH2 Its accuracy was evaluated from measurements of plasma obtained during intravenous infusions (1.5 pmol × kg(-1) × min(-1)) of GLP-1 7-36NH2 in healthy subjects and patients with type 2 diabetes. Plasma levels of the endogenous GLP-1 metabolite increased during a meal challenge in patients with type 2 diabetes, and treatment with a DPP-4 inhibitor fully blocked its formation. Accurate measurements of the GLP-1 metabolite may contribute to understanding its physiology and role of GLP-1 in diabetes. Copyright © 2017 the American Physiological Society.

  6. Enhancing expression of the pseudorabies virus glycoprotein E in yeast and its application in an indirect sandwich ELISA.

    Science.gov (United States)

    Wu, C-Y; Wu, C-W; Liao, C-M; Chien, M-S; Huang, C

    2017-09-01

    The purpose of this study was to produce a recombinant pseudorabies virus (PRV) glycoprotein E (gE) protein with the correct antigenicity for use as a low-cost diagnostic antigen. The gene fragment encoding the amino-terminal immunodominant region of PRV gE (codons 31-270) (gEN31-270) was codon optimized and expressed constitutively and secreted using a Pichia pastoris expression system. Yeast-expressed gEN31-270 (ygEN31-270) was harvested from the culture supernatant, and ygEN31-270 was shown to exhibit N-linked glycosylation. An indirect sandwich enzyme-linked immunosorbent assay (ELISA) was developed using ygEN31-270 as a coating antigen, and the results showed that the assay had high sensitivity and specificity, as well as almost perfect concordance with a commercial gE ELISA kit. The immunodominant region (amino acids 31-270) of gE was expressed successfully in P. pastoris using a codon optimization strategy. ygEN31-270 was secreted and N-glycosylated. The ygEN31-270-based indirect sandwich ELISA showed high sensitivity and specificity to detect gE-specific antibodies in swine serum samples. The ygEN31-270-based indirect sandwich ELISA may provide an alternative method for developing a diagnostic kit with easy manipulation and low cost. © 2017 The Society for Applied Microbiology.

  7. Preparation of anti-ciguatoxin monoclonal antibodies using synthetic haptens: sandwich ELISA detection of ciguatoxins.

    Science.gov (United States)

    Tsumuraya, Takeshi; Fujii, Ikuo; Hirama, Masahiro

    2014-01-01

    Ciguatera fish poisoning (CFP) is a form of food poisoning caused by the consumption of fish that have accumulated a type of sodium channel activator toxin called ciguatoxins (CTXs), which are produced by dinoflagellates of the genus Gambierdiscus through the food chain. CFP affects more than 50000 people each year. The extremely low level of CTXs in tainted fish has hampered the development of antibodies for the detection of these toxins. Monoclonal antibodies (mAbs) specific against major congeners of CTX3C, 51-hydroxyCTX3C, CTX1B, and 54-deoxyCTX1B were prepared by immunization of mice with protein conjugates of rationally designed synthetic haptens in place of the natural toxins. We found that haptenic groups possessing a surface area larger than 400 angstroms2 were required to produce mAbs that can bind strongly to CTXs. Direct sandwich ELISA utilizing two different monoclonal antibodies that bind specifically to one of the two wings of a CTX were established to detect CTXs. No cross-reactivity was observed against the other marine toxins tested, including brevetoxin A, brevetoxin B, okadaic acid, and maitotoxin.

  8. A High-Throughput, Precipitating Colorimetric Sandwich ELISA Microarray for Shiga Toxins

    Directory of Open Access Journals (Sweden)

    Andrew Gehring

    2014-06-01

    Full Text Available Shiga toxins 1 and 2 (Stx1 and Stx2 from Shiga toxin-producing E. coli (STEC bacteria were simultaneously detected with a newly developed, high-throughput antibody microarray platform. The proteinaceous toxins were immobilized and sandwiched between biorecognition elements (monoclonal antibodies and pooled horseradish peroxidase (HRP-conjugated monoclonal antibodies. Following the reaction of HRP with the precipitating chromogenic substrate (metal enhanced 3,3-diaminobenzidine tetrahydrochloride or DAB, the formation of a colored product was quantitatively measured with an inexpensive flatbed page scanner. The colorimetric ELISA microarray was demonstrated to detect Stx1 and Stx2 at levels as low as ~4.5 ng/mL within ~2 h of total assay time with a narrow linear dynamic range of ~1–2 orders of magnitude and saturation levels well above background. Stx1 and/or Stx2 produced by various strains of STEC were also detected following the treatment of cultured cells with mitomycin C (a toxin-inducing antibiotic and/or B-PER (a cell-disrupting, protein extraction reagent. Semi-quantitative detection of Shiga toxins was demonstrated to be sporadic among various STEC strains following incubation with mitomycin C; however, further reaction with B-PER generally resulted in the detection of or increased detection of Stx1, relative to Stx2, produced by STECs inoculated into either axenic broth culture or culture broth containing ground beef.

  9. Implementation of microfluidic sandwich ELISA for superior detection of plant pathogens.

    Directory of Open Access Journals (Sweden)

    Numrin Thaitrong

    Full Text Available Rapid and economical screening of plant pathogens is a high-priority need in the seed industry. Crop quality control and disease surveillance demand early and accurate detection in addition to robustness, scalability, and cost efficiency typically required for selective breeding and certification programs. Compared to conventional bench-top detection techniques routinely employed, a microfluidic-based approach offers unique benefits to address these needs simultaneously. To our knowledge, this work reports the first attempt to perform microfluidic sandwich ELISA for Acidovorax citrulli (Ac, watermelon silver mottle virus (WSMoV, and melon yellow spot virus (MYSV screening. The immunoassay occurs on the surface of a reaction chamber represented by a microfluidic channel. The capillary force within the microchannel draws a reagent into the reaction chamber as well as facilitates assay incubation. Because the underlying pad automatically absorbs excess fluid, the only operation required is sequential loading of buffers/reagents. Buffer selection, antibody concentrations, and sample loading scheme were optimized for each pathogen. Assay optimization reveals that the 20-folds lower sample volume demanded by the microchannel structure outweighs the 2- to 4-folds higher antibody concentrations required, resulting in overall 5-10 folds of reagent savings. In addition to cutting the assay time by more than 50%, the new platform offers 65% cost savings from less reagent consumption and labor cost. Our study also shows 12.5-, 2-, and 4-fold improvement in assay sensitivity for Ac, WSMoV, and MYSV, respectively. Practical feasibility is demonstrated using 19 real plant samples. Given a standard 96-well plate format, the developed assay is compatible with commercial fluorescent plate readers and readily amendable to robotic liquid handling systems for completely hand-free assay automation.

  10. Development of a sandwich ELISA-type system for the detection and quantification of hazelnut in model chocolates.

    Science.gov (United States)

    Costa, Joana; Ansari, Parisa; Mafra, Isabel; Oliveira, M Beatriz P P; Baumgartner, Sabine

    2015-04-15

    Hazelnut is one of the most appreciated nuts being virtually found in a wide range of processed foods. The simple presence of trace amounts of hazelnut in foods can represent a potential risk for eliciting allergic reactions in sensitised individuals. The correct labelling of processed foods is mandatory to avoid adverse reactions. Therefore, adequate methodology evaluating the presence of offending foods is of great importance. Thus, the aim of this study was to develop a highly specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of hazelnut in complex food matrices. Using in-house produced antibodies, an ELISA system was developed capable to detect hazelnut down to 1 mg kg(-1) and quantify this nut down to 50 mg kg(-1) in chocolates spiked with known amounts of hazelnut. These results highlight and reinforce the value of ELISA as rapid and reliable tool for the detection of allergens in foods.

  11. Electronic States in Quasi-one-Dimensional Copolymeric Sandwich Structures

    Institute of Scientific and Technical Information of China (English)

    刘德胜; 王鹿霞; 魏建华; 郑斌; 解士杰; 韩圣浩; 梅良模

    2001-01-01

    The electronic properties of xPA/nPPP/yPA sandwiched copo]ymers with a well-barrier-well structure have been studied by using a tight-binding calculation. It was found that the electronic properties of the neutral states of these sandwiched copolymers are sensitive to the constitutions of PPP and PA monomers and the interface coupling between PA and PPP. It is verified that the quantum tunnelling effect will occur at the lowest conductive state of xPA/nPPP/xPA copolymers.

  12. Development and evaluation of a sandwich ELISA for quantification of the 20S proteasome in human plasma

    DEFF Research Database (Denmark)

    Dutaud, Dominique; Aubry, Laurent; Henry, Laurent

    2002-01-01

    Because quantification of the 20S proteasome by functional activity measurements is difficult and inaccurate, we have developed an indirect sandwich enzyme-linked immunosorbent assays (ELISA) for quantification of the 20S proteasome in human plasma. This sandwich ELISA uses a combination...... of a monoclonal antibody (mcp 20) recognizing the C2-beta subunit of human 20S proteasome (Mr˜30,000) and a polyclonal rabbit anti-20S antibody which labels different subunits of the complex. The detection limit of the assay was established as 10 ng/ml (n=10, mean of zero standard+2 S.D.) and the recovery rate...... ranged from 96% to 104%. The within-run and between-run coefficients of variation (CV) ranges were 2.8–3.3 and 3.0–3.4, respectively. Using serial dilutions of plasma to which various amounts of purified 20S proteasome were added, a linear dose–response was observed between 102 and 2050 ng...

  13. A high-throughput, precipitating colorimetric sandwich ELISA microarray for shiga toxins

    Science.gov (United States)

    Shiga toxins 1 and 2 (Stx1 and Stx2) from Shiga toxin-producing E. coli (STEC) bacteria were simultaneously detected with a newly developed, high-throughput antibody microarray platform. The proteinaceous toxins were immobilized and sandwiched between biorecognition elements (monoclonal antibodies)...

  14. Establishment of a convenient sandwich-ELISA for direct quantification of glucosyltransferase-I: application for dual diagnosis of dental caries.

    Science.gov (United States)

    Hashizume-Takizawa, Tomomi; Shinozaki-Kuwahara, Noriko; Tomita, Naoya; Kurita-Ochiai, Tomoko

    2014-04-01

    Previously, we established a convenient enzyme-linked immunosorbent assay (ELISA) system targeting glucosyltransferase (GTF)-B derived from Streptococcus mutans for diagnosing caries risk. However, it has been reported that S. sobrinus possesses high cariogenicity and is more frequently detected in highly caries-susceptible patients than S. mutans is. S. sobrinus can secrete GTF-I, an important cariogenic factor for dental plaque formation, as well as S. mutans GTF-B. Therefore, in this study, we developed another feasible ELISA system targeting S. sobrinus GTF-I that would ensure caries risk determination by combined GTF-I and GTF-B levels. A readily measurable sandwich-ELISA system was devised, which consisted of monoclonal and polyclonal antibodies against GTF-I. The developed sandwich-ELISA system quantified the purified GTF-I with sensitivity and specificity, and a positive correlation was observed between the amount of GTF-I extracted from clinical plaque samples and S. sobrinus levels. Furthermore, high levels of GTF-I and GTF-B were detected using the sandwich-ELISA system in caries-susceptible subjects. These results indicate that the sandwich-ELISA system against GTF-I developed in this study is useful, and that the dual detection of the caries risk factors GTF-I and GTF-B is helpful for predicting caries risk.

  15. A sandwich ELISA for the detection of neuraminidase of avian influenza A(H7N9) virus.

    Science.gov (United States)

    Yu, Yueyang; Zhang, Xi; Zhao, Baihui; Sun, Ying; Zhang, Xiaoguang; Bai, Tian; Lu, Jian; Li, Zi; Liu, Liqi; Wang, Dayan; Shu, Yuelong; Zhou, Jianfang; Qin, Kun

    2017-09-01

    Although exhibiting no or low virulence in poultry, avian influenza virus H7N9 has caused around 1400 confirmed human infections in China with a case-fatality rate of 30% since 2013. A highly pathogenic H7N9 virus (HP-H7), with the HA antigenicity distinct from the previous, were recently detected in patients and poultry. Therefore, convenient rapid diagnosis with reliability will allow early antiviral use and management for H7N9 infection. Here, a sandwich ELISA targeting the conserved viral antigen, neuraminidase (NA) was developed. The immunoassay employed mouse monoclonal antibody (mAb) 3C1 to specifically capture the N9 and 3E9 for the detection. Its limit of detection is 6.25ng/ml for N9 protein of A/Anhui/1/2013(H7N9, AH1/2013) and 0.125HAU/50μL for live virus, AH1/2013 and A/Environment/Jiangxi/28/2009 (H11N9), respectively. When applied to test the five clinic throat swabs from H7N9 patients confirmed by nuclear acid testing (NAT) using quantitative reverse-transcriptase polymerase chain reaction (Q-PCR), two samples showed positive result in sandwich ELISA while all were negative using commercial Flu A and H7 subtype rapid antigen tests (RAT). The ELISA using anti-N9 mAbs provided a valuable approach to detect H7N9 virus and quantify the N9 protein. Copyright © 2017. Published by Elsevier B.V.

  16. One-step antibody immobilization-based rapid and highly-sensitive sandwich ELISA procedure for potential in vitro diagnostics.

    Science.gov (United States)

    Vashist, Sandeep Kumar; Marion Schneider, E; Lam, Edmond; Hrapovic, Sabahudin; Luong, John H T

    2014-03-18

    An improved enzyme-linked immunosorbent (ELISA) assay using one-step antibody immobilization has been developed for the detection of human fetuin A (HFA), a specific biomarker for atherosclerosis and hepatocellular carcinoma. The anti-HFA formed a stable complex with 3-aminopropyltriethoxysilane (APTES) by ionic and hydrophobic interactions. The complex adsorbed on microtiter plates exhibited a detection range of 4.9 pg mL(-1) to 20 ng mL(-1) HFA, with a limit of detection of 7 pg mL(-1). Furthermore, an analytical sensitivity of 10 pg mL(-1) was achieved, representing a 51-fold increase in sensitivity over the commercial sandwich ELISA kit. The results obtained for HFA spiked in diluted human whole blood and plasma showed the same precision as the commercial kit. When stored at 4°C in 0.1 M phosphate-buffered saline (PBS, pH 7.4), the anti-HFA bound microtiter plates displayed no significant decrease in their functional activity after two months. The new ELISA procedure was extended for the detection of C-reactive protein, human albumin and human lipocalin-2 with excellent analytical performance.

  17. Development and validation of a sandwich ELISA for the determination of potentially allergenic sesame (Sesamum indicum) in food.

    Science.gov (United States)

    Redl, Gerda; Husain, Fatima T; Bretbacher, Ines E; Nemes, Albert; Cichna-Markl, Margit

    2010-10-01

    This paper presents a sandwich enzyme-linked immunosorbent assay (ELISA) that allows the determination of traces of sesame in food. Chicken anti-sesame antibodies, used as coating antibodies, and rabbit anti-sesame antibodies, used as secondary antibodies, were prepared by immunization with a protein extract of white, peeled sesame. The ELISA did not show any cross-reactivity with 19 food ingredients commonly found in sesame-containing foodstuffs such as seeds, nuts, and cereals. In whole grain bread, crisp toast, and snacks, the limit of detection (S/N = 3) was 0.5, 0.5, and 0.3 μg sesame protein/g, and the limit of quantification (S/N = 10) was 0.6, 0.8, and 1.4 μg sesame protein/g, respectively. The analysis of blank food matrices (whole grain bread, white bread, crisp toast, and snacks) spiked with sesame protein at four spike levels generally resulted in mean recoveries from 72% to 145%. In the case of spiking blank food matrices with sesame seeds, the ELISA proved to be more accurate for whole wheat cookies than for whole wheat bread.

  18. Sandwich enzyme-linked immunosorbent assay (ELISA) for detection of cashew nut in foods.

    Science.gov (United States)

    Gaskin, Ferdelie E; Taylor, Steve L

    2011-01-01

    The presence of undeclared cashew can pose a health risk to cashew-allergic consumers. The food industry has the responsibility to declare the presence of cashews on packaged foods even when trace residues are or might be present. The objective of this study was to develop a rapid, sensitive, and specific enzyme-linked immunosorbent assay (ELISA) for the detection of cashew residues. Raw and roasted cashews were defatted and used separately to immunize sheep, goats, and rabbits. The cashew ELISA was developed using sheep and rabbit polyclonal anti-roasted cashew sera as capture and detector reagents, respectively, with visualization through an alkaline phosphatase-mediated substrate reaction. The cashew ELISA was shown to have a limit of quantification of 1 ppm (1 μg cashew/g). The ELISA was highly specific except that substantial cross-reactivity was noted with pistachio and a lesser degree of cross-reactivity was noted with hazelnut. The performance of the ELISA was assessed by manufacturing cookies, ice cream, and milk chocolate with added known amounts (0 to 1000 ppm) of cashew. The mean percent recoveries for ice cream, cookies, and milk chocolate were 118%± 2.9%, 84.3%± 4.0%, and 104%± 3.0%, respectively. In a limited retail survey, 4/5 retail samples with cashew declared on ingredient labels tested positive for cashew compared to 5/36 samples of foods with precautionary labels indicating the possible presence of one or more tree nuts and 0/18 samples without cashew declared on the label in any manner. The cashew ELISA can be used to detect undeclared cashew residue in foods and as a potential tool for the food industry to assess the effectiveness of allergen control strategies and to guarantee compliance with food labeling regulatory requirements.

  19. Assessment of natural variability of maize lipid transfer protein using a validated sandwich ELISA

    Science.gov (United States)

    Lipid transfer protein (LTP) is the main causative agent for rare food allergic reactions to maize. This report describes a new, validated ELISA that accurately measures LTP concentrations from 0.2 to 6.4 ng/ml. The levels of LTP ranged from 171 to 865 µg/g grain, a 5.1 fold differences, across a ...

  20. Development and validation of sensitive sandwich ELISAs for two investigational nonapeptide metastin receptor agonists, TAK-448 and TAK-683.

    Science.gov (United States)

    Yoshida, Nobuyo; Nishizawa, Naoki; Matsui, Hisanori; Moriya, Yuu; Kitada, Chieko; Asami, Taiji; Matsumoto, Hirokazu

    2012-11-01

    TAK-448 and TAK-683, investigational agents with potential utility in the treatment of prostate cancer, are potent low molecular weight metastin receptor agonists consisting of nine amino acids. Monoclonal antibodies (mAbs) against these agents were developed to facilitate their evaluation in preclinical studies. Six mAbs were obtained from four immunogens. Three mAbs recognized the C-terminal of TAK-683 and TAK-448, two recognized the N-terminal of TAK-683, and one recognized the N-terminal of TAK-448. Using various combinations of these six mAbs, sandwich ELISAs for TAK-448 and TAK-683 were developed. These assays were highly sensitive, specific, and accurate. The detection limit for TAK-448 and TAK-683 was 3 and 5 pg/mL, respectively, and there was no interference from rat plasma, rat metastin, or analogs of TAK-448/TAK-683. Recovery achieved ≤±10% with intra-/inter-day assay precision coefficient of variation <10%. The assay demonstrated high stability and sample pre-treatment was not required. Each assay detected the dose-dependent concentration of TAK-448 and TAK-683 in blood 24h after a single intravenous administration of 0.1 and 1mg/kg doses. In conclusion, sensitive sandwich ELISAs were developed to detect the small peptides TAK-448 and TAK-683. The novel assays reliably quantified these nonapeptides in rat plasma, and thus will be useful for preclinical studies of these agents. This methodology may be applicable to the development of similar assays for other short peptides.

  1. Determination of Aspergillus pathogens in agricultural products by a specific nanobody-polyclonal antibody sandwich ELISA.

    Science.gov (United States)

    Wang, Ting; Li, Peiwu; Zhang, Qi; Zhang, Wen; Zhang, Zhaowei; Wang, Tong; He, Ting

    2017-06-28

    Aspergillus and its poisonous mycotoxins are distributed worldwide throughout the environment and are of particular interest in agriculture and food safety. In order to develop a specific method for rapid detection of Aspergillus flavus to forecast diseases and control aflatoxins, a nanobody, PO8-VHH, highly reactive to A. flavus was isolated from an immunized alpaca nanobody library by phage display. The nanobody was verified to bind to the components of extracellular and intracellular antigen from both A. flavus and A. parasiticus. To construct a sandwich format immunoassay, polyclonal antibodies against Aspergillus were raised with rabbits. Finally, a highly selective nanobody-polyclonal antibody sandwich enzyme-linked immunosorbent assay was optimized and developed. The results revealed that the detection limits of the two fungi were as low as 1 μg mL(-1), and that it is able to detect fungal concentrations below to 2 μg mg(-1) of peanut and maize grains in both artificially and naturally contaminated samples. Therefore, we here provided a rapid and simple method for monitoring Aspergillus spp. contamination in agricultural products.

  2. Detection of ruminant meat and bone meal in feeds by sandwich ELISA with monoclonal antibodies.

    Science.gov (United States)

    Yamamoto, Takayuki; Kato, Masatoshi; Endo, Kiwamu; Kotoura, Satoshi; Takeda, Zenya

    2016-01-01

    A sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) using two monoclonal antibodies directed against a synthetic peptide with an amino-acid sequence related to the C-terminus of bovine myoglobin and the whole molecule of sodium dodecyl sulphate (SDS)-denatured bovine myoglobin was adapted for detecting bovine myoglobin in contaminated feeds. The ELISA employed bovine meat extract of a known myoglobin concentration as a calibration standard and had an limit of detection (LOD) of 3.54 ng/ml and an limit of quantification (LOQ) of 11.0 ng/ml corresponding to 0.022% and 0.067% (wt/wt) bovine meat-and-bone-meal (MBM) mixed in 20-fold-diluted feed extracts, respectively. A cut-off threshold of 20.6 ng/ml bovine myoglobin was set to simplify ELISA and facilitate quick assessment of test results without a tedious calibration process. The ELISA was able to detect bovine MBM in artificially prepared model feeds, mixed botanical feeds, mixed botanical feeds with skimmed milk, fish meal, pork meal and pork/chicken meal at 0.1% (wt/wt). It was also able to detect sheep MBM in test feeds, but showed no reactivity to swine MBM, chicken MBM, skimmed milk or gelatine of bovine origin. The advantages of this method are the quick and easy extraction protocol of proteins from test feeds, using 100 mM sodium sulphide and 0.6% sodium dodecyl sulphate in the extraction solution and the effective detection of bovine and sheep MBM at 0.1% (wt/wt).

  3. Quantitation of Leishmania infantum in tissues of infected BALB/c mouse by sandwich ELISA.

    Science.gov (United States)

    Ferrua, B; Le Fichoux, Y; Suffia, I; Rousseau, D; Roptin, C; Kubar, J

    2001-01-01

    In this report, a sandwhich ELISA was developed to quantify spleen and liver burdens from L. infantum-infected BALB/c mice. Amastigote antigens obtained following Nonidet P40 extraction of parasite-harbouring tissues were captured by anti-L. infantum human IgG insolubilized onto microtiter plate and subsequently revealed with anti-L. infantum F(ab)' fragments labelled with peroxidase. The method was easy to perform, precise and capable to specifically and accurately detect 5 x 10(4) amastigotes/100 mg tissue. Parasite burdens from infected BALB/c mice, in various conditions, were measured by ELISA and Giemsa-stained touch imprint reference methods, and compared. Both techniques agreed well with close values for liver burdens, but the spleen loads measured by the ELISA were, on average, 10.7 times higher than those calculated from imprints. This difference was attributed partly to the underestimation brought by Stauber's formula. However, it did not preclude the usefulness of this newly developed test, since results obtained in kinetics studies and evaluation of the efficiency of leishmanicidal drugs allowed us to draw identical conclusions.

  4. Optimisation of sandwich ELISA based on monoclonal antibodies for the specific measurement of pregnancy-associated plasma protein (PAPP-A) in acute coronary syndrome

    DEFF Research Database (Denmark)

    Rossen, Marie; Iversen, Kasper; Teisner, Ane

    2007-01-01

    OBJECTIVES: PAPP-A has become the principal biochemical serum marker in first trimester screening for Down syndrome, the original data being based on results of a radioimmunoassay (RIA). Recent observations using sandwich ELISA technology have proposed PAPP-A as a potential marker in patients wit...

  5. Immunodiagnosis of paramphistomosis using monoclonal antibody-based sandwich ELISA for detection of Paramphistomum gracile circulating 16 kDa antigen.

    Science.gov (United States)

    Anuracpreeda, Panat; Tepsupornkul, Kullanid; Chawengkirttikul, Runglawan

    2017-06-01

    In this study, we have produced a monoclonal antibody (MoAb) against 16 kDa antigen of Paramphistomum gracile (16 kDaAgPg), and developed an accurate sandwich enzyme-linked immunosorbent assay (sandwich ELISA) for the detection of circulating 16 kDaAg in the serum and fecal samples from cattle naturally infected with P. gracile. MoAb 1D10 was immobilized on a microtitre plate, and the antigen in the samples was captured and detected with biotinylated rabbit anti-16 kDaAgPg antibody. The lower detection limit of sandwich ELISA was 3·5 pg mL-1, and no cross-reaction with other parasite antigens was evaluated. The reliability of the assay was examined using the serum and fecal samples from cattle naturally infected with P. gracile, Fasciola gigantica, Moniezia benedeni, Trichuris sp., Strongyloides sp., strongylids and non-infected animals. The sandwich ELISA showed the sensitivity, specificity and accuracy at 98·33, 100 and 99·55% (serum samples), and 96·67, 100 and 99·09% (fecal samples). Therefore, this detection method is a rapid and excellent potential assay for the accurate diagnosis of paramphistomosis.

  6. Development and validation of a direct homologous quantitative sandwich ELISA for fathead minnow (Pimephales promelas) vitellogenin.

    Science.gov (United States)

    Eidem, Janne K; Kleivdal, Hans; Kroll, Kevin; Denslow, Nancy; van Aerle, Ronny; Tyler, Charles; Panter, Grace; Hutchinson, Tom; Goksøyr, Anders

    2006-06-15

    . Chem. 75, 2343-2353]. This paper describes the development and validation of a new, homologous enzyme-linked immunosorbent assay (ELISA) for quantification of Vtg in this fish species.

  7. Diagnostic efficacy of monoclonal antibody based sandwich enzyme linked immunosorbent assay (ELISA for detection of Fasciola gigantica excretory/secretory antigens in both serum and stool

    Directory of Open Access Journals (Sweden)

    Zoheiry Mona K

    2011-09-01

    Full Text Available Abstract Background This research was carried out to develop a reliable monoclonal antibody (MoAb-based sandwich enzyme linked immunosorbent assay (ELISA for the diagnosis of active Fasciola gigantica infection in both serum and stool for comparative purposes. Methods From a panel of MoAbs raised against F. gigantica excretory/secretory antigens (ES Ags, a pair (12B/11D/3F and 10A/9D/10G was chosen due to its high reactivity and strict specificity to F. gigantica antigen by indirect ELISA. Results The two MoAbs were of the IgG1 and IgG2a subclasses, respectively. Using SDS-PAGE and EITB, the selected MoAbs recognized 83, 64, 45 and 26 kDa bands of ES Ags. The lower detection limit of ELISA assay was 3 ng/ml. In stool, the sensitivity, specificity and diagnostic efficacy of ELISA was 96%, 98.2 and 97.1%; while in serum they were 94%, 94.6% and 94.3%, respectively. Moreover, a positive correlation was found between ova count in stool of F. gigantica infected patients and the OD readings of ELISA in both stool and serum samples (r = 0.730, p Conclusions These data showed that the use of MoAb-based sandwich ELISA for the detection of F. gigantica coproantigens in stool specimens was superior to serum samples; it provides a highly efficient, non-invasive technique for the diagnosis of active F. gigantica infection.

  8. Establishment of a Sandwich ELISA Method for Detection of Vascular Endothelial Growth Factor in Serum Samples of Hepatocellular Carcinoma Patients1

    Institute of Scientific and Technical Information of China (English)

    BING SHAN; JING-QUN HU; PING ZHAO; JUN HAN; XIAO-PING DONG; CHEN GAO; JIAN-MING CHEN; XIN-YU BI; BAO-YUN ZHANG; YAN GUO; CHEN-FANG DONG; RUN AN; QI SHI

    2008-01-01

    Objective To establish a sandwich ELISA method for detecting vascular endothelial growth factor(VEGF)in sera of population and the patients with hepatocellular carcinoma(HCC). Methods Full length and two truncated human VEGF cDNA sequences were amplified from a commercial plasmid pBLAST49-bVEGF by PCR and inserted into the prokaryotic-expression plasmid pET-32a or pGEX-2T. Various VEGF proteins were expressed and purified from E. coli in His-Trx or GST fusion forms.The specific VEGF antibodies were elicited in experimental rabbits and mice by immunization of the full length VEGF fusion protein His-Trx-VEGF1-165.After purification of antibodies with chromatograph of Protein G.a sandwich ELISA technique was established.Serum VEGF levels were evaluated in 229 adults and 291 HCC patients.Results SDS-PAGE displayed that the molecular weights of the expressed full length(His-Trx-VEGF1-165),N-terminal(His-Trx-VEGF1-100)and C-terminal(GST-VEGF100-165)human VEGF fusion proteins were about 38KD,31KD,and 33KD,respectively.Western blots confirmed that the prepared antisera were able to recognize both prokaryoticly and eukaryoticly expressed recombinant VEGF proteins.Assays of serially diluted His-Trx-VEGF1-100 by the established sandwich ELISA method showed that the linear range of the standard curve was 0.625-320 ng/mL.with the squared correlation coefficient R2=0.991.Screening of a serum panel containing 291 serum samples of HCC patients and 229 health adults rovealed that the average VEGF level in HCC patients was higher than that in healthy controls,with a statically significant difference. Conclusion The established sandwich ELISA reflects the level of serum VEGF and provide scientific basis for scrcening metastasis and recurrence of HCC using serum VEGF as an index.

  9. Development of sandwich dot-ELISA for specific detection of Ochratoxin A and its application on to contaminated cereal grains originating from India

    Directory of Open Access Journals (Sweden)

    M. eVenkataramana

    2015-05-01

    Full Text Available In the present study, generation and characterization of a highly specific monoclonal antibody (mAb against Ochratoxin A (OTA was undertaken. The generated mAb was further used to develop a simple, fast and sensitive sandwich dot-ELISA (s-dot ELISA method for detection of OTA from contaminated food grain samples. The LOD (limit of detetion of the developed ELISA method was determined as 5.0 ng/mL of OTA. Developed method was more specific towards OTA and no cross reactivity was observed with the other tested mycotoxins such as deoxynivalenol, fumonisin B1 or aflatoxin B1. To assess the utility and reliability of the developed method, several field samples of maize, wheat and rice (n=195 collected from different geographical regions of southern Karnataka region of India were evaluated for the OTA occurrence. Seventy two out of 195 samples (19 maize, 38 wheat and 15 rice were found to be contaminated by OTA by s-dot ELISA. The assay results were further co-evaluated with conventional analytical HPLC method. Results of the s-dot ELISA are in concordance with HPLC except for 3 samples that were negative for OTA presence by s-dot ELISA but found positive by HPLC. Although positive by HPLC, the amount of OTA in the three samples was found to be lesser than the accepted levels (>5 µg/kg of OTA presence in cereals. Therefore, in conclusion, the developed s-dot ELISA is a better alternative for routine cereal based food and feed analysis in diagnostic labs to check the presence of OTA over existing conventional culture based, tedious analytical methods.

  10. Development of a H2 O2 -sensitive quantum dots-based fluorescent sandwich ELISA for sensitive detection of bovine β-lactoglobulin by monoclonal antibody.

    Science.gov (United States)

    He, Shengfa; Li, Xin; Gao, Jinyan; Tong, Ping; Chen, Hongbing

    2017-06-16

    Bovine β-lactoglobulin (BLG) is the major allergen in cows' milk, and the specific epitope plays a key role in food allergy. Developing a method specifically bind to the IgE epitope is necessary for testing BLG and its allergenic residues. The monoclonal antibody (1G9) specific to the IgE linear epitope for BLG was identified as high affinity and specificity. Based on 1G9, a sensitive fluorescent sandwich enzyme-linked immunosorbent assay (sELISA) was successfully developed using catalase-mediated fluorescence quenching of thiolated CdTe quantum dots in the presence of hydrogen peroxide as fluorescent signal output. The fluorescent sELISA showed high sensitivity and specificity, the limit of detection was 0.49 ng mL(-1) , which was 16-fold lower than horseradish peroxidase (HRP)-based sELISA. The linear range for BLG detection were 125-4000 ng mL(-1) (r = 0.9939) and 0.48-62.5 ng mL(-1) (r = 0.9919). The recoveries and coefficients of variation were 94.25-109.83% and 4.38-20.29%, respectively. Allergenic residues were also detected in hydrolysed infant formulas. The results of fluorescent sELISA showed good performance as HRP-based sELISA and commercial sELISA kit. This proposed fluorescent sELISA could be employed to detect BLG and its allergenic residues in food with highly sensitivity, reliability, and recovery. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  11. Development of sandwich ELISA for testing bovine β-lactoglobulin allergenic residues by specific polyclonal antibody against human IgE binding epitopes.

    Science.gov (United States)

    He, Shengfa; Li, Xin; Gao, Jinyan; Tong, Ping; Chen, Hongbing

    2017-07-15

    Bovine β-lactoglobulin (BLG) is the main allergen in cows' milk, and the most commonly used method for detecting BLG is enzyme-linked immunosorbent assay (ELISA). However, antibodies used in commercial ELISA kits do not recognize specifically BLG IgE epitopes. Here, an antibody specific to IgE linear epitopes for BLG was used to develop a sandwich ELISA using a rabbit anti-BLG polyclonal antibody. The linear range for BLG detection was 31.25-8000ng/mL and limit of detection was 1.96ng/mL. BLG content in dairy samples was determined, and there was a good agreement between this immunoassay and reversed-phase high-performance liquid chromatography with high recovery. Additionally, BLG content in food samples had an average recovery of 104.25%. Allergenic residues were also detected in hydrolyzed infant formulas. The method developed could be a practical approach to determine BLG and its allergenic residues in food with a high degree of sensitivity, reliability and recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Electronic transport in nanoparticle monolayers sandwiched between graphene electrodes.

    Science.gov (United States)

    Lu, Chenguang; Zhang, Datong; van der Zande, Arend; Kim, Philip; Herman, Irving P

    2014-11-06

    Graphene/CdSe nanoparticle monolayer/graphene sandwich structures were fabricated to explore the interactions between these layered materials. Electrical transport across these heterostructures suggests that transport is limited by tunneling through the nanoparticle (NP) ligands but not the NP core itself. Photoconductivity suggests ligands may affect the exciton separation efficiency.

  13. Development and optimization of a double antibody sandwich ELISA for the detection of goose T cell surface CD8α molecule

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; YANG Qiao; WU Ying; CHEN Xiao-yue; CHENG An-chun; CHENG Bei-bei; CHEN Shun; WANG Ming-shu; JIA Ren-yong; ZHU De-kang; LIU Ma-feng; LIU Fei; SUN Kun-feng

    2016-01-01

    CD8, a glycoprotein on the surface of T cels, is involved in the defense against viral infection and plays signiifcant roles in antigen presentation and in the antiviral immune response. CD8 is composed of two chains. Of these, the CD8α chain was chosen for the detection because it involved in both the CD8αα homodimer and the CD8αβ heterodimer. Here, we established a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for speciifc detection of goose CD8α (goCD8α). The results showed that the optimal coated antibody and antigen dilutions were 1:50 (the antibody titer was 1:12800) and 1:32 (0.3 ng mL–1), respectively, while the optimal capture antibody and horseradish peroxidase (HRP)-la-beled goat anti-rabbit IgG dilutions were 1:50 (the antibody titer was 1:51200) and 1:4000 (the antibody titer was 1:5000), respectively. The optimal blocking buffer was 5% bovine serum albumin (BSA). The best incubating condition was overnight at 4°C, the best blocking time was 120 min and the best anti-capture antibody working time was 150 min. In addition, the minimum dose detectable by DAS-ELISA was 5×10–3 ng mL–1. Most importantly, goCD8α expression levels in goose spleen mononuclear cels (MNCs) post-Goose parvoviruse (GPV) infection were found to be signiifcantly up-regulated using the DAS-ELISA method, which was consistent with previous results obtained using real-time quantitative PCR. In conclusion, the DAS-ELISA method reported here is a novel, speciifc technique for the clinical detection of goCD8α.

  14. Detection and confirmation of PPR virus antigen in sheep and goats by sandwich-ELISA and RT-PCR in Andhra Pradesh, India

    Directory of Open Access Journals (Sweden)

    G. Saritha

    2015-06-01

    Full Text Available Peste des petits ruminants (PPR is a highly contagious disease of domestic and wild small ruminants. Rapid and accurate laboratory assay are essential to enable the implementation of appropriate control strategies to restrict the spread of PPR. The present study was designed to detect the PPR virus (PPRV antigen (N-gene in nasal swabs and tissue samples. A total of 195 samples comprising of 138 nasal swabs from PPR suspected sheep (n=72 and goats (n=66, and 57 tissue samples comprising of lymph nodes from dead sheep (n=39 and goats (n=18 were collected from certain parts of Andhra Pradesh. The samples were subjected to sandwich-ELISA followed by RT-PCR for confirmatory diagnosis. In this study, PPRV could be detected in 27.53% (n=38/138 nasal swabs and 49.12% (n=28/57 tissue samples. Data showed that PPRV infection is widespread in the Andhra Pradesh, India.

  15. A New Sandwich ELISA for Quantification of Thymidine Kinase 1 Protein Levels in Sera from Dogs with Different Malignancies Can Aid in Disease Management.

    Science.gov (United States)

    Jagarlamudi, Kiran Kumar; Moreau, Laura; Westberg, Sara; Rönnberg, Henrik; Eriksson, Staffan

    2015-01-01

    Thymidine kinase 1 (TK1) is a DNA precursor enzyme whose expression is closely correlated with cell proliferation and cell turnover. Sensitive serum TK1 activity assays have been used for monitoring and prognosis of hematological malignancies in both humans and dogs. Here we describe the development of a specific sandwich TK1-ELISA for the quantification of TK1 protein levels in sera from dogs with different malignancies. A combination of rabbit polyclonal anti-dog TK1 antibody and a mouse monoclonal anti-human TK1 antibody was used. Different concentrations of recombinant canine TK1 was used as standard. Clinical evaluation of the ELISA was done by using sera from 42 healthy dogs, 43 dogs with hematological tumors and 55 with solid tumors. An established [3H]-dThd phosphorylation assay was used to determine the TK1 activity levels in the same sera. The mean TK1 activities in dogs with hematological tumors were significantly higher than those found in healthy dogs. In agreement with earlier studies, no significant difference was observed in serum TK1 activities between healthy dogs and dogs with solid tumors. However, the mean TK1 protein levels determined by new TK1-ELISA were significantly higher not only in hematological tumors but also in solid tumors compared to healthy dogs (mean ± SD = 1.30 ± 1.16, 0.67 ± 0.55 and 0.27± 0.10 ng/mL, respectively). Moreover, TK1-ELISA had significantly higher ability to distinguish lymphoma cases from healthy based on receiver operating characteristic analyses (area under the curve, AUC, of 0.96) to that of the activity assay (AUC, 0.84). Furthermore, fluctuations in TK1 protein levels during the course of chemotherapy in dogs with lymphoma closely associated with clinical outcome. Overall, the TK1-ELISA showed significant linear correlation with the TK1 activity assay (rs = 0.6, p<0.0001). Thus, the new TK1-ELISA has sufficient sensitivity and specificity for routine clinical use in veterinary oncology.

  16. Entamoeba histolytica: detection of coproantigens by purified antibody in the capture sandwich ELISA Entamoeba histolytica: detecção de coproantígenos por ELISA de captura utilizando anticorpo purificado

    Directory of Open Access Journals (Sweden)

    Haidee Urdaneta

    1994-12-01

    Full Text Available A sensitive and specific Capture Sandwich ELISA (CSE was developed using polyclonal purified rabbit antibodies against three different axenic strains of Entamoeba histolytica: CSP from Brazil and HM1 - IMSS from Mexico, for the detection of coproantigens in fecal samples. Immunoglobulin G (IgG againstis E. histolytica was isolated from rabbits immunized with throphozoites whole extract in two stages: affinity chromatography in a column containing E. histolytica antigens bound to Sepharose 4B was followed by another chromatography in Sepharose antibodies 4B-Protein A. A Capture Sandwich ELISA using purified antibodies was able to detect 70ng of amebae protein, showing a sensitivity of 93% and specificity of 94%. The combination of microscopic examination and CSE gave a concordance and discordance of 93.25% and 6.75%, respectively. It was concluded that CSE is highly specific for the detection of coproantigens of E. histolytica in feces of infected patients, is quicker to perform, easier and more sensitive than microscopic examination.Foi desenvolvido um teste de ELISA de Captura usando anticorpos policlonais purificados obtidos em coelhos contra três diferentes cepas axênicas de Entamoeba histolytica (ICB-CSP and ICB-462 do Brasil e HM1 do México para detecção de coproantígenos em amostras de fezes de indivíduos: a sintomáticos, b assintomáticos, c com outros parasitos intestinais, e d sadios. Imunoglobulina G (IgG contra E. histolytica foi isolada de imune soro de coelho, em duas etapas: cromatografia de afinidade em uma coluna contendo antígenos de E. histolytica unidos à Sepharose 4B, seguido por outra cromatografía em Sepharose 4B Proteína A. O teste de ELISA usando anticorpos purificados, foi capaz de detectar até um só trofozoíto por lâmina ou 70 ng de proteína de ameba por orifício, apresentando uma sensibilidade de 93% e uma especificidade de 94%. A combinação do exame microscópico com o método de ELISA de Captura

  17. Fundamental study on reactivities of gluten protein types from wheat, rye and barley with five sandwich ELISA test kits.

    Science.gov (United States)

    Lexhaller, Barbara; Tompos, Christine; Scherf, Katharina Anne

    2017-12-15

    Monitoring the compliance of gluten-free foods to the regulatory threshold of 20mg/kg of gluten is essential for celiac disease patients. The different enzyme-linked immunosorbent assays (ELISAs) for gluten detection each have specific characteristics, but there are only a few systematic comparisons. This fundamental study compared the specificities and sensitivities of the R5, G12 and Skerritt monoclonal and two polyclonal antibodies to well-defined gluten protein types (GPT) isolated from wheat, rye and barley flours. Quantitation of protein concentrations by reversed-phase high-performance liquid chromatography provided independent reference values. The ELISA responses showed high variability depending on the type of cereal, the GPT and the antibody used. Overall, ω1,2-gliadins and γ-75k-secalins were most reactive, whereas ω5-gliadins and γ-, B- and D-hordeins were detected with the lowest sensitivities. These results revealed which GPT each antibody is most sensitive to and provided novel insights that will be helpful for appropriate calibration of ELISAs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Direct ELISA.

    Science.gov (United States)

    Lin, Alice V

    2015-01-01

    First described by Engvall and Perlmann, the enzyme-linked immunosorbent assay (ELISA) is a rapid and sensitive method for detection and quantitation of an antigen using an enzyme-labeled antibody. Besides routine laboratory usage, ELISA has been utilized in medical field and food industry as diagnostic and quality control tools. Traditionally performed in 96-well or 384-well polystyrene plates, the technology has expanded to other platforms with increase in automation. Depending on the antigen epitope and availability of specific antibody, there are variations in ELISA setup. The four basic formats are direct, indirect, sandwich, and competitive ELISAs. Direct ELISA is the simplest format requiring an antigen and an enzyme-conjugated antibody specific to the antigen. This chapter describes the individual steps for detection of a plate-bound antigen using a horseradish peroxidase (HRP)-conjugated antibody and luminol-based enhanced chemiluminescence (ECL) substrate. The methodological approach to optimize the assay by chessboard titration is also provided.

  19. Production of mono- and polyclonal antibodies to Citrus leprosis virus C2 and their application in triple antibody sandwich ELISA and immunocapture RT-PCR diagnostic assays.

    Science.gov (United States)

    Choudhary, Nandlal; Roy, Avijit; Leon, M G; Wei, G; Nakhla, M K; Levy, L; Brlansky, R H

    2017-05-01

    The newly discovered Citrus leprosis virus cytoplasmic type 2 (CiLV-C2) is one of the causal virus of citrus leprosis disease complex; which leads to substantial loss of citrus production in the states of Meta and Casanare of Colombia. Specific and sensitive detection methods are needed to monitor the dissemination of CiLV-C2 in Colombia, and to prevent introduction of CiLV-C2 to other citrus growing countries. Toward this end, putative coat protein gene (CPG) of CiLV-C2 was amplified from CiLV-C2 infected citrus tissues. The CPG was cloned, expressed and purified a recombinant coat protein of ∼31kDa which used to generate monoclonal antibodies and polyclonal antisera. Four monoclonal antibodies and two polyclonal antisera were selected as being specific following Western blotting. The monoclonal antibody MAb E5 and polyclonal antiserum PAb UF715 were selected testing with an extract of CiLV-C2 infected leaves using triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). In addition, an immunocapture RT-PCR was standardized using MAb E5 for specific and sensitive detection of CiLV-C2. The standardized TAS-ELISA and IC-RT-PCR were able to detect CiLV-C2 in the extracts of symptomatic citrus leprosis tissues up to the dilutions of 1:160 and 1:2580, respectively. Result demonstrated that CiLV-C2 is present in citrus orchards in Meta and Casanare citrus growing areas of Colombia. TAS-ELISA could be used for routine detection of CiLV-C2, epidemiological studies, and for border inspections for quarantine purposes. IC-RT-PCR could be valuable for CiLV-C2 validation and viral genome analysis.

  20. A sandwich ELISA for porcine alpha-1 acid glycoprotein (pAGP, ORM-1) and further demonstration of its use to evaluate growth potential in newborn pigs.

    Science.gov (United States)

    Caperna, T J; Shannon, A E; Stoll, M; Kahl, S; Blomberg, L A; Vallet, J L; Ramsay, T G

    2017-07-01

    A simple, reproducible sandwich, ELISA was developed to measure porcine alpha-1 acid glycoprotein (pAGP, ORM-1) in pig plasma. Porcine AGP isolated from serum was purchased and a polyclonal antisera was prepared in rabbits using the whole pAGP molecule as immunogen. The antiserum was affinity purified, and a portion of the purified antibody fraction was labeled with horseradish peroxidase. Porcine AGP protein was used as a standard, whereas commercially available buffers and reagents were utilized throughout the assay. The assay was specific for pAGP, had a lower limit of detection of 3.2 ng/mL, and could be used to quantify pAGP in plasma or serum. Using this ELISA, we corroborated our previous findings obtained by RID assay, which demonstrated that the AGP concentration in newborn piglets is negatively associated with preweaning growth rate. The current data were obtained using piglets from a different geographical location and genetic background and showed that elevated AGP at birth was associated with reduced preweaning growth rate (P < 0.001, r = 0.433, n = 19 litters). In addition, litters with a greater average AGP at birth were at a growth disadvantage compared with litters with reduced average AGP plasma concentrations (P < 0.001, r = 0.708, n = 19 litters). Litter average plasma AGP was a better predictor of litter preweaning growth rate than average litter birth weight. The data represent further support for using perinatal AGP concentrations as a tool to identify potential slower growing pigs and as a plasma biomarker for predicting litter growth rate. Published by Elsevier Inc.

  1. Sandwiched confinement of quantum dots in graphene matrix for efficient electron transfer and photocurrent production

    DEFF Research Database (Denmark)

    Zhu, Nan; Zheng, Kaibo; J. Karki, Khadga

    2015-01-01

    matrix via interfacial self-assembly, leading to the formation of sandwiched hybrid QD-graphene nanofilms. We have explored structural features, electron transfer kinetics and photocurrent generation capacity of such hybrid nanofilms using a wide variety of advanced techniques. Graphene nanosheets...

  2. A new monoclonal antibody (5D3-F7) which recognizes human monocyte-chemotactic protein-1 but not related chemokines. Development of a sandwich ELISA and in situ detection of producing cells.

    Science.gov (United States)

    Peri, G; Milanese, C; Matteucci, C; Ruco, L; Zhou, D; Sozzani, S; Coletta, I; Mantovani, A

    1994-09-14

    Chemokines are a superfamily of structurally related cytokines involved in leukocyte recruitment in normal and neoplastic tissues. The availability of non-cross-reacting reagents specific for each member of the C-C and C-X-C family is important for careful characterization of their in vitro and in vivo production and relevance. Here we describe a novel, highly specific, mAb against monocyte chemotactic protein-1 (MCP-1). The 5D3-F7 mAb (IgG1,kappa) recognizes human recombinant and natural MCP-1 in ELISA, immunoprecipitation and immunoblot analysis. As a source of natural MCP-1 we used the 8387 human sarcoma line which produces spontaneously MCP-1 and responds to TNF with increased expression and release. The 5D3-F7 mAb inhibited the chemotactic activity of MCP-1 for monocytes. Using the 5D3-F7 mAb and a polyclonal rabbit anti-MCP-1 serum, a sandwich ELISA was developed. In both the direct and the sandwich ELISA, the 5D3-F7 mAb recognized human MCP-1, but not the closely related C-C chemokines MCP-1, MCP-2, MCP-3, MIP-1 alpha, and RANTES and the C-X-C chemokines IL-8, gro alpha and NAP-2. In culture supernatants the sensitivity of the sandwich ELISA was approximately equal to 30 pg/ml. The sandwich ELISA permitted detection of MCP-1 in resting or cytokine-stimulated endothelial, mesothelial and Kaposi's sarcoma cells. Preliminary immunohistochemical analysis revealed production of MCP-1 by macrophage-like cells at sites of inflammation. The 5D3-F7 mAb provides a novel, highly specific reagent with which to investigate the in vitro and in vivo production and role of MCP-1.

  3. Development of a monoclonal antibody against the left wing of ciguatoxin CTX1B: thiol strategy and detection using a sandwich ELISA.

    Science.gov (United States)

    Tsumuraya, Takeshi; Takeuchi, Katsutoshi; Yamashita, Shuji; Fujii, Ikuo; Hirama, Masahiro

    2012-09-01

    Ciguatera fish poisoning (CFP) is a form of food poisoning caused by the ingestion of a variety of reef fish that have accumulated trace amounts of ciguatoxins produced by dinoflagellates of the genus Gambierdiscus through the food chain. CFP affects more than 50,000 people each year. The extremely low level of the causative neurotoxins, ciguatoxins, in fish has hampered the preparation of antibodies for detecting the toxins. In this paper, we describe a thiol strategy for synthesizing a keyhole limpet hemocyanin (KLH)-conjugate (20) of the ABCDE-ring fragment of the Pacific ciguatoxins, CTX1B (1) and 54-deoxyCTX1B (4). We succeeded in producing a monoclonal antibody (3G8) against the left wings of these ciguatoxins by immunizing mice with the hapten-KLH conjugate (20) as the synthetic antigen. The most promising mAb, 3G8, does not cross-react with other related marine toxins. Sandwich enzyme-linked immunosorbent assay (ELISA) utilizing 3G8 and the previously prepared monoclonal antibody (8H4) enabled us to detect 1 specifically at less than 0.28 ng/mL.

  4. Quantitative Detection of the Foot-And-Mouth Disease Virus Serotype O 146S Antigen for Vaccine Production Using a Double-Antibody Sandwich ELISA and Nonlinear Standard Curves.

    Directory of Open Access Journals (Sweden)

    Xia Feng

    Full Text Available The efficacy of an inactivated foot-and-mouth disease (FMD vaccine is mainly dependent on the integrity of the foot-and-mouth disease virus (FMDV particles. At present, the standard method to quantify the active component, the 146S antigen, of FMD vaccines is sucrose density gradient (SDG analysis. However, this method is highly operator dependent and difficult to automate. In contrast, the enzyme-linked immunosorbent assay (ELISA is a time-saving technique that provides greater simplicity and sensitivity. To establish a valid method to detect and quantify the 146S antigen of a serotype O FMD vaccine, a double-antibody sandwich (DAS ELISA was compared with an SDG analysis. The DAS ELISA was highly correlated with the SDG method (R2 = 0.9215, P<0.01. In contrast to the SDG method, the DAS ELISA was rapid, robust, repeatable and highly sensitive, with a minimum quantification limit of 0.06 μg/mL. This method can be used to determine the effective antigen yields in inactivated vaccines and thus represents an alternative for assessing the potency of FMD vaccines in vitro. But it still needs to be prospectively validated by analyzing a new vaccine preparation and determining the proper protective dose followed by an in vivo vaccination-challenge study to confirm the ELISA findings.

  5. Quantitative Detection of the Foot-And-Mouth Disease Virus Serotype O 146S Antigen for Vaccine Production Using a Double-Antibody Sandwich ELISA and Nonlinear Standard Curves.

    Science.gov (United States)

    Feng, Xia; Ma, Jun-Wu; Sun, Shi-Qi; Guo, Hui-Chen; Yang, Ya-Min; Jin, Ye; Zhou, Guang-Qing; He, Ji-Jun; Guo, Jian-Hong; Qi, Shu-yun; Lin, Mi; Cai, Hu; Liu, Xiang-Tao

    2016-01-01

    The efficacy of an inactivated foot-and-mouth disease (FMD) vaccine is mainly dependent on the integrity of the foot-and-mouth disease virus (FMDV) particles. At present, the standard method to quantify the active component, the 146S antigen, of FMD vaccines is sucrose density gradient (SDG) analysis. However, this method is highly operator dependent and difficult to automate. In contrast, the enzyme-linked immunosorbent assay (ELISA) is a time-saving technique that provides greater simplicity and sensitivity. To establish a valid method to detect and quantify the 146S antigen of a serotype O FMD vaccine, a double-antibody sandwich (DAS) ELISA was compared with an SDG analysis. The DAS ELISA was highly correlated with the SDG method (R2 = 0.9215, P<0.01). In contrast to the SDG method, the DAS ELISA was rapid, robust, repeatable and highly sensitive, with a minimum quantification limit of 0.06 μg/mL. This method can be used to determine the effective antigen yields in inactivated vaccines and thus represents an alternative for assessing the potency of FMD vaccines in vitro. But it still needs to be prospectively validated by analyzing a new vaccine preparation and determining the proper protective dose followed by an in vivo vaccination-challenge study to confirm the ELISA findings.

  6. 基于IgY的ELISA用于囊尾蚴循环抗原的检测%Detecting the circulating antigen(CA) of Taenia solium cysticercosis with specific egg yolk antibody (IgY) by sandwich ELISA

    Institute of Scientific and Technical Information of China (English)

    刘玉; 王元伦; 唐雨德

    2013-01-01

    Objective To develop a sensitive and specific double antibody sandwich enzyme-linked immunosorbent assay (ELISA) to detect circulating antigen (CA) of Taeniasoliumcysticercosis with chicken egg yolk immunoglobulin antibodies (IgY).Methods Hens were subcutaneously immunized with CA and the crude IgY was extracted from egg yolk by water dilution method.A sandwich ELISA had been developed by purified IgY antibodies as capture antibody and monoclonal antibodies labeled with peroxidase as detecting antibody.The detection limits of CA were analyzed.The sera and cerebrospinal fluid of patients,the sera of healthy people,sick pigs and healthy pigs were detected in parallel by the established ELISA methods.It's sensitivity and specificity were evaluated by comparison with ELISA based monoclonal antibodies.Results The minimal detectable concentration of CA was 8.3 and 13.9 μg/ml by sandwich ELISA based IgY and monoclonal antibodies,respectively.The positive rates of samples from 139 patients,19 cerebrospinal fluid of patients and 222 sick pigs were 100% (139/139),89.5% (17/19) and 100% (222/222) by sandwich ELISA based IgY respectively.The negative rates of samples from 50 healthy people and 20 healthy pigs were 100%.Conclusion The novel double-antibody sandwich ELISA using anti-CA IgY appears to be sensitive and specific for detection the CA of Taenia solium cysticercosis.It is the promising assay for immunodiagnosis of Taenia solium cysticercosis.%目的 建立基于IgY的双抗体夹心ELISA用于囊尾蚴病的诊断.方法 制备并纯化抗囊尾蚴循环抗原(CA)卵黄抗体(IgY),建立以抗CA的IgY为捕获抗体,酶标记抗CA的单克隆抗体1A5为检测抗体的双抗体夹心ELISA法,共检测样品450份,并与捕获抗体和检测抗体均为单克隆抗体的ELISA法比较,验证方法的敏感性、特异性与实用性.结果 成功制备并鉴定了特异性IgY抗体,建立了基于Igy的双抗体夹心ELISA检测体系.IgY-ELISA和双单

  7. 两种方法检测汉坦病毒滴度的比较研究%A Comparison of Double-antibody Sandwich ELISA and Direct Immunofluoresence Asssy for Detecting and Titering Hantavirus

    Institute of Scientific and Technical Information of China (English)

    白露; 叶伟; 于蒙蒙; 张亮; 于澜; 刘梓谕; 吴兴安; 徐志凯; 张芳琳

    2012-01-01

    比较双抗体夹心ELISA法与直接免疫荧光(DFA)法在检测汉坦病毒灵敏度方面的差别.用汉坦病毒76-118株感染Vero-E6细胞,取不同时间点的病毒感染细胞制备细胞爬片或细胞培养物冻融上清,分别用本室制备的抗汉坦病毒单克隆抗体标记荧光素或辣根过氧化物酶( HRP),建立直接免疫荧光法和双抗体夹心ELISA法检测上述细胞中的病毒抗原,并比较两者的检测灵敏度.用空斑形成实验结果作为金标准,以评价两种方法在检测病毒抗原灵敏度方面的差异.结果:用两种检测方法测定不同时间点的汉坦病毒培养物抗原,双抗体夹心ELISA法不仅检出的时间早,而且其病毒滴度均较IFA法高(P<0.01).说明ELISA法检测汉坦病毒滴度的灵敏度较IFA法更高,并且操作简单、可重复性好、便于大批量规模化检测,因此更适用于汉坦病毒的检测.%To compare the sensitivity between double antibody sandwich ELISA and direct immunofluorescence assay ( DFA) for detection of hantavirus, Vero-E6 cells were infected by Hantaan virus strain 76-118. Cell climb ing slices or freeze-thaw cell culture supernatant was prepared and fluorescein labeled anti-hantavirus monoclonal antibody or horseradish peroxidase ( HRP) labeled monoclonal antibody was used to establish method of double-an tibody sandwich ELISA or direct IFA to detect viral antigen in these cells, and plaque reduction nuetralization test was used as control. And then the optimal detection times were identified and the sensitivity of the two methods was compared. It is resulted that virus titer detected by double-antibody sandwich ELISA was obviously higher than that of DFA (P <0. 01) , and the time point when the virus antigen was detected is more earlier in ELISA than in IFA. It is conclused the sensitivity of double-antibody sandwich ELISA was better than that of direct IFA in detecting hantavirus. And the former method was repeatable and easier to

  8. Effects of valence, geometry and electronic correlations on transport in transition metal benzene sandwich molecules

    Science.gov (United States)

    Karolak, M.; Jacob, D.

    2016-11-01

    We study the impact of the valence and the geometry on the electronic structure and transport properties of different transition metal-benzene sandwich molecules bridging the tips of a Cu nanocontact. Our density-functional calculations show that the electronic transport properties of the molecules depend strongly on the molecular geometry which can be controlled by the nanocontact tips. Depending on the valence of the transition metal center certain molecules can be tuned in and out of half-metallic behaviour facilitating potential spintronics applications. We also discuss our results in the framework of an Anderson impurity model, indicating cases where the inclusion of local correlations alters the ground state qualitatively. For Co and V centered molecules we find indications of an orbital Kondo effect.

  9. 双抗体夹心ELISA检测人胎儿血红蛋白体系的建立%Establishment of a sandwich-ELISA system for determination of human fetal hemoglobin

    Institute of Scientific and Technical Information of China (English)

    李雪丽; 文李艳; 冯善伟; 钟梅; 刘艳君; 富宁

    2012-01-01

    目的 建立一种定量检测人胎儿血红蛋白(HbF)的双抗体夹心ELISA方法.方法 用抗人HbF单抗作为捕获抗体,加入待测抗原,检测抗体为兔抗人HbF多克隆抗体,最后加入辣根过氧化物酶标记的羊抗兔IgG.结果 本检测体系灵敏度约为0.039 μg/ml,测量范围0.039-24.66 μg/ml,特异性强,重复性好,100份血标本的检测结果与高效液相色谱法结果符合率高.结论 建立了一种可用于检测人外周血HbF的双抗体夹心ELISA方法,有望为临床上诊断某些与HbF有关的疾病提供帮助.%Objective To establish a sandwich ELISA for the determination of fetal hemoglobin (HbF) in human blood. Methods An anti HbF monoclonal antibody was coated on polystyrene microtiter plates followed by blocking with 5% defat milkithen samples for detection were added to the wells,followed by anti HbF polyclonal antibody pre pared, from rabbit; at last 、addition of HRP goat anti rabbit IgG and. Conventional color development were performed. Re suits This sandwich ELISA system can determine HbF specifically,the sensitivity for HbF is 0. 039 μg/ml,the range of detection is 0. 039 - 24. 66 μg/ml. Conclusion This HbF ELISA is applicable for research and observation in clini cal.

  10. The Electronic Logbook for the Information Storage of ATLAS Experiment at LHC (ELisA)

    Science.gov (United States)

    Corso Radu, A.; Lehmann Miotto, G.; Magnoni, L.

    2012-12-01

    A large experiment like ATLAS at LHC (CERN), with over three thousand members and a shift crew of 15 people running the experiment 24/7, needs an easy and reliable tool to gather all the information concerning the experiment development, installation, deployment and exploitation over its lifetime. With the increasing number of users and the accumulation of stored information since the experiment start-up, the electronic logbook actually in use, ATLOG, started to show its limitations in terms of speed and usability. Its monolithic architecture makes the maintenance and implementation of new functionality a hard-to-almost-impossible process. A new tool ELisA has been developed to replace the existing ATLOG. It is based on modern web technologies: the Spring framework using a Model-View-Controller architecture was chosen, thus helping building flexible and easy to maintain applications. The new tool implements all features of the old electronic logbook with increased performance and better graphics: it uses the same database back-end for portability reasons. In addition, several new requirements have been accommodated which could not be implemented in ATLOG. This paper describes the architecture, implementation and performance of ELisA, with particular emphasis on the choices that allowed having a scalable and very fast system and on the aspects that could be re-used in different contexts to build a similar application.

  11. 水貂肠炎病毒双抗体夹心ELISA检测方法的建立%Establishment of double antibody sandwich ELISA for detection of mink enteritis virus

    Institute of Scientific and Technical Information of China (English)

    王建科; 程世鹏; 易立; 杨莘; 罗彬; 许红丽; 闫喜军; 武华

    2011-01-01

    In order to establish double antibody sandwich enzyme-linked immunosorbent assay(DAS-ELISA) for detection of mink enteritis virus(MEV),anti-MEV monoclonal antibody and rabbit anti-MEV polyclonal antibody were used as the capture antibody and detecting antibody,respectively. The optimal dilution of the capture antibody and the detecting antibody capable of detecting MEV antigens were 1: 20 and 1: 3 200 in the check-board titration respectively. Positive samples with MEV,Aleutian mink disease virus and canine distemper virus were examined by the established ELISA respectively. In result,the developed DAS-ELISA had good specificity. A total of 158 samples were tested both by the developed DAS-ELISA and by polymerase chain reaction(PCR). 40 of the tested samples were positive by the developed ADS-ELISA and 44 by PCR. The specificity and sensitivity of the developed DAS-ELISA were 95.6 %and 79.5 %, respectively. The coincidental rate between the developed DAS-ELISA and PCR was 91.1%. These results indicated that the developed DAS-ELISA was suitable for rapid detection and epidemiological investigation of MEV infection in mink.%以抗水貂肠炎病毒(mink enteritis virus,MEV)单克隆抗体为捕获抗体、兔抗MEV多克隆抗体为检测抗体,建立了MEV双抗体夹心ELISA检测方法.该方法用于MEV抗原的检测.经过试验,单克隆抗体的最适稀释度为1:20,兔抗MEV多克隆抗体的最适稀释度为1:3200.用该ELISA方法分别检测MEV、水貂阿留中病痛毒、犬瘟热病毒样品.结果表明,ELISA方法具有良好的特异性.用该ELISA和PCR同时检测158份临床样品,其中ELISA检测40份为阳性,PCR检测44份为阳性,该ELISA的特异性和敏感性分别为95.6%和79.5%,这2种方法的符合率为91.1%.该方法的建立为MEV的检测及水貂病毒性肠炎的流行病学调查提供了工具.

  12. Development and application of a fecal antigen diagnostic sandwich ELISA for estimating prevalence of Fasciola gigantica in cattle in central Java, Indonesia.

    Science.gov (United States)

    Estuningsih, Endah; Spithill, Terry; Raadsma, Herman; Law, Ruby; Adiwinata, G; Meeusen, Els; Piedrafita, David

    2009-04-01

    The purpose of this study was to compare the sensitivity and specificity of an ELISA test to detect Fasciola gigantica antigens (coproantigens) in bovine feces, with fecal egg counting and an ELISA for detecting anti-F. gigantica antibodies in serum. Monoclonal antibodies to cathepsin L were generated and used to capture this antigen in feces of infected cattle. Blood, feces, and livers were collected from 150 cattle at an abattoir in Jakarta, Indonesia, for anti-Fasciola antibodies, coproantigen detection, and F. gigantica egg and worm counts. Fluke recovery varied from 1 to 426 per host, with a mean of 32 flukes. The results showed that the sensitivity and specificity of coproantigen detecting ELISA (95 and 91%, respectively) was better than the anti-F. gigantica antibody ELISA (91 and 88%, respectively) and to fecal egg counting (87 and 100%, respectively). The coproantigen ELISA was able to detect 100% of the cattle with >15 flukes. A survey of 305 cattle in central Java over a 10-mo period validated this test in the field, demonstrating a high prevalence of fascioliasis and establishing the test as a useful diagnostic method to determine patent F. gigantica infections in cattle.

  13. Sandwiched confinement of quantum dots in graphene matrix for efficient electron transfer and photocurrent production.

    Science.gov (United States)

    Zhu, Nan; Zheng, Kaibo; Karki, Khadga J; Abdellah, Mohamed; Zhu, Qiushi; Carlson, Stefan; Haase, Dörthe; Žídek, Karel; Ulstrup, Jens; Canton, Sophie E; Pullerits, Tõnu; Chi, Qijin

    2015-05-21

    Quantum dots (QDs) and graphene are both promising materials for the development of new-generation optoelectronic devices. Towards this end, synergic assembly of these two building blocks is a key step but remains a challenge. Here, we show a one-step strategy for organizing QDs in a graphene matrix via interfacial self-assembly, leading to the formation of sandwiched hybrid QD-graphene nanofilms. We have explored structural features, electron transfer kinetics and photocurrent generation capacity of such hybrid nanofilms using a wide variety of advanced techniques. Graphene nanosheets interlink QDs and significantly improve electronic coupling, resulting in fast electron transfer from photoexcited QDs to graphene with a rate constant of 1.3 × 10(9) s(-1). Efficient electron transfer dramatically enhances photocurrent generation in a liquid-junction QD-sensitized solar cell where the hybrid nanofilm acts as a photoanode. We thereby demonstrate a cost-effective method to construct large-area QD-graphene hybrid nanofilms with straightforward scale-up potential for optoelectronic applications.

  14. Sandwiched confinement of quantum dots in graphene matrix for efficient electron transfer and photocurrent production

    Science.gov (United States)

    Zhu, Nan; Zheng, Kaibo; Karki, Khadga J.; Abdellah, Mohamed; Zhu, Qiushi; Carlson, Stefan; Haase, Dörthe; Žídek, Karel; Ulstrup, Jens; Canton, Sophie E.; Pullerits, Tõnu; Chi, Qijin

    2015-05-01

    Quantum dots (QDs) and graphene are both promising materials for the development of new-generation optoelectronic devices. Towards this end, synergic assembly of these two building blocks is a key step but remains a challenge. Here, we show a one-step strategy for organizing QDs in a graphene matrix via interfacial self-assembly, leading to the formation of sandwiched hybrid QD-graphene nanofilms. We have explored structural features, electron transfer kinetics and photocurrent generation capacity of such hybrid nanofilms using a wide variety of advanced techniques. Graphene nanosheets interlink QDs and significantly improve electronic coupling, resulting in fast electron transfer from photoexcited QDs to graphene with a rate constant of 1.3 × 109 s-1. Efficient electron transfer dramatically enhances photocurrent generation in a liquid-junction QD-sensitized solar cell where the hybrid nanofilm acts as a photoanode. We thereby demonstrate a cost-effective method to construct large-area QD-graphene hybrid nanofilms with straightforward scale-up potential for optoelectronic applications.

  15. Electron paramagnetic resonance study of chosen gadolinium(III) sandwiched- and encapsulated-polyoxometalate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Szyczewski, A.; Kruczynski, Z.; Pietrzak, J. [Uniwersytet Adama Mickiewicza, Poznan (Poland). Inst. Fizyki; Lis, S.; But, S.; Elbanowski, M. [Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan (Poland)

    1998-07-24

    The gadolinium(III) complexes with polyoxometalates were studied using X-band electron paramagnetic resonance (EPR) spectroscopy. We selected the following sandwiched complexes: Gd(SiW{sub 11}O{sub 39}){sub 2}{sup 13-} [I], GdW{sub 10}O{sub 36}{sup 9-} [II], Gd(P{sub 2}W{sub 17}O{sub 61}){sub 2}{sup 17-} [III], and encrypted [GdSb{sub 9}W{sub 17}O{sub 86}]{sup 16-} [IV], [GdP{sub 5}W{sub 30}O{sub 110}]{sup 12-} [V]. The EPR spectra obtained for the compounds I-III and IV-V differ markedly from the U-spectrum characteristic for Gd(III) in glasses. The values of the zero-field splitting parameter D for both kind of complexes studied have been estimated. Taking into account the spin-hamiltonian calculations, the existence of Gd(III) ion in two different surroundings, in a strong crystal field of rhombic symmetry and in a weak crystal field, is observed. The differences observed between the case I-III and IV-V seems to be related to a various coordination of the Gd(III) ion and its hydration degree. Our study shows a relation between the presence of particular g-values of the spectral lines and the number of the inner-sphere water molecules as well as the type of the Gd(III) complex (sandwiched and/or encrypted) in solid. (orig.) 14 refs.

  16. 单克隆抗体与多克隆抗体配对ELISA方法比较%Study of the Optimum Pairing of Polyclonal Antibodies and Monoclonal Antibodies with Sandwich ELISA

    Institute of Scientific and Technical Information of China (English)

    张小兵; 邸禄芹; 吴萌; 闫静辉

    2009-01-01

    Using human chorionic gonadotrophin( HCG) as the antigen,polyclonal antibodies and monoclonal antibodies(McAbs) specific for HCG were generated, characterized and highly purified. Then these antibodies were labeled with horseradish peroxidase (HRP). By a double antibody sandwich enzyme-linked immunosorhent assay, several problems of the optimum pairing of polyclonal antibodies and monoclonal antibodies were discussed. The results showed that with monoclonal antibody as trapping antibody and polyclonal antibody labeling with enzyme as testing antibody which should be diluted with animal sera as diluent,the sandwich ELISA had a highly specificity and sensitivity to detect antigen.%以人绒毛膜促性腺激素(HCG)为抗原,制备出对HCG的多克隆抗体和特异性单克隆抗体,并进行抗体纯化和特性分析,利用辣根过氧化物酶(HRP)分别对其进行了标记.采用双抗夹心ELISA试验,探讨了多克隆抗体与单克隆抗体配对的若干事项.结果表明,利用单克隆抗体和酶标多克隆抗体配对,并用含动物血清的稀释液稀释酶标抗体,可实现对检测原的高特异性和高灵敏度检测.

  17. 测定脑膜炎球菌疫苗C群多糖的双抗体夹心ELISA法的建立%Establishment of a double antibody sandwich ELISA for determination of group C polysaccharide in meningococcal polysaccharide vaccine

    Institute of Scientific and Technical Information of China (English)

    潘殊男; 肖詹蓉; 王宇星; 张霖阳; 史雨舟; 王玲; 张萍

    2012-01-01

    Objective To establish a double antibody sandwich ELISA for determination of group C polysaccharide in groups A,C,Y,W135 meningococcal polysaccharide vaccine (MPV4).Methods The prepared polyclonal antibodies against group C polysaccharide were purified by octanoic acid-ammonium sulfate precipitation method,and then labeled with horseradish peroxidase by sodium periodate method.The polyclonal antibodies against group C polysaccharide were used as coated antibodies and the second enzyme-labled antibodies to establish a double antibody sandwich ELISA.The reaction conditions of the established ELISA were optimized,and specific quantitative determination of group C polysaccharide was carried out by the established ELISA.Results The specificity of the double antibody sandwich ELISA for determination of group C polysaccharide was high,and no cross reactions with groups A,Y and W135 were detected.The best linearity in dose-response curve of group C polysaccharide was found in a range of 2.5-20.0 ng/ml (r > 0.99).The precision and accuracy of the established ELISA were good.Coefficients of variation and recovery rates of intraand inter-assay were 0.6%-9.1% and 87.5%-100.0%,respectively.Quantitation limit was identified as 4.0 ng/ml.Group C polysaccharide contents,molecular dimension KDvalue and recovery rates of three batches of MPV4 detected by the established ELISA were in accordance with those of previous determination and temporary quality control standards.Conclusion The double antibody sandwich ELISA can be applied to detecting the key quality indexes of group C polysaccharide in MPV4.%目的 建立测定A、C、Y、W135群脑膜炎球菌多糖疫苗(groups A,C,Y,W135 meningococcal polysaccharide vaccine,MPV4)C群多糖含量的双抗体夹心ELISA法.方法 制备抗C群多糖多克隆抗体,所得的多克隆抗体经辛酸-硫酸铵沉淀法纯化后,用过碘酸钠法对其标记辣根过氧化物酶.分别将抗C群多糖多克隆抗体作为包被抗

  18. Sensitivity improvement of a sandwich-type ELISA immunosensor for the detection of different prostate-specific antigen isoforms in human serum using electrochemical impedance spectroscopy and an ordered and hierarchically organized interfacial supramolecular architecture.

    Science.gov (United States)

    Gutiérrez-Zúñiga, Gabriela Guadalupe; Hernández-López, José Luis

    2016-01-01

    A gold millielectrode (GME) functionalized with a mixed (16-MHA + EG3SH) self-assembled monolayer (SAM) was used to fabricate an indirect enzyme-linked immunosorbent assay (ELISA) immunosensor for the sensitive detection of prostate-specific antigen (PSA), a prostate cancer (PCa) biomarker, in human serum samples. To address and minimize the issue of non-specific protein adsorption, an organic matrix (amine-PEG3-biotin/avidin) was assembled on the previously functionalized electrode surface to build up an ordered and hierarchically organized interfacial supramolecular architecture: Au/16-MHA/EG3SH/amine-PEG3-biotin/avidin. The electrode was then exposed to serum samples at different concentrations of a sandwich-type immunocomplex molecule ((Btn)Ab-AgPSA-(HRP)Ab), and its interfacial properties were characterized using electrochemical impedance spectroscopy (EIS). Calibration curves for polarization resistance (RP) and capacitance (1/C) vs. total and free PSA concentrations were obtained and their analytical quality parameters were determined. This approach was compared with results obtained from a commercially available ELISA immunosensor. The results obtained in this work showed that the proposed immunosensor can be successfully applied to analyze serum samples of patients representative of the Mexican population.

  19. Electron and Phonon Dynamics in Hexagonal Pd Nanosheets and Ag/Pd/Ag Sandwich Nanoplates.

    Science.gov (United States)

    Wang, Li; Sagaguchi, Takuya; Okuhata, Tomoki; Tsuboi, Motohiro; Tamai, Naoto

    2017-02-28

    Pd and its hybrid nanostructures have attracted considerable attention over the past decade, with both catalytic and plasmonic properties. The electron and phonon properties directly govern conversion efficiencies in applications such as energy collectors and photocatalysts. We report the dynamic processes of electron-phonon coupling and coherent acoustic phonon vibration in hexagonal Pd nanosheets and Ag/Pd/Ag sandwich nanoplates using transient absorption spectroscopy. The electron-phonon coupling constant of Pd nanosheets, GPd-nanosheet (8.7 × 10(17) W/(m(3)·K)) is larger than that of the bulk GPd (5.0 × 10(17) W/(m(3)·K)). The effective coupling constant Geff of Ag/Pd/Ag nanoplates decreases with increasing Ag shell thickness, finally approaching the bulk GAg. The variation of Geff is explained in terms of reduced density of states near Fermi level of Pd nanosheets with 1.8 nm ultrathin thickness. Coherent acoustic phonon vibration in Pd nanosheets is assigned to a fundamental breathing mode, similar to the vibration of benzene. The period increases with increasing Ag shell thickness. For Ag/Pd/Ag nanoplates with 20 nm thick Ag shells, the vibrational mode is ascribed to a quasi-extensional mode. The results show that the modes of the coherent acoustic phonon vibration transform with the geometric variation of Pd nanosheets and Ag/Pd/Ag nanoplates. Our results represent an understanding of quantum-confinement related electron dynamics and bulk-like phonon kinetics in the ultrathin Pd nanosheets and their hybrid nanostructures.

  20. Antigen sandwiched ELISA for detection of total HIV antibodies%检测抗HIV-1/2型抗体的双抗原夹心方法的建立及其试剂盒的研制

    Institute of Scientific and Technical Information of China (English)

    侯俊; 何红霞; 貌盼勇; 洪世雯; 胡燕; 沈宏辉; 杨松涛

    2001-01-01

    Objective To establish a sensitive antigen sandwiched ELISA(AS) for detection of the total antibodies to HIV-1/2. Methods Based on the gene sequence of HIV-1/2 type and its coded amino acid structure,5 polypeptides were synthesized as coated antigens using solid-phase method. These polypeptides were labelled with horseradish peroxidase. And the total antibodies of HIV-1/2 were detected with the same method. Results These reagents were detected by three batches of HIV panel from The National Institute for the Control of Pharmaceutical and Biological Products (NICPBP). The results indicated that the corresponding rate was 100 %. The variant coefficient rate was less than 10 %. A comparison of antigen sandwiched ELISA with indirect ELISA in detection of a panel(20 positive sera and 20 negative sera) from the NICPBP showed that the general coincident rate of indirect ELISA was 92.5 % and the sandwiched system was 100 %. The HIV-AS diagnostic reagent kits have passed the quality examination of NICPBP. A comparison of antigen sandwiched ELISA with Yapei reagents in detection of 90 normal sera and 88 positive sera for HIV-1/2 showed that the coincident rate was 100%. The reagents were stable at 37℃ for 4 days. This indicated that our reagents were highly specific, sensitive and stable. Conclusion Our antigen sandwiched ELISA reagent for total antibodies of HIV has a merit of sensitivity specificity and stability. It can be clinically used for detection of HIV-1/2 infection and in blood bank for the screening of blood donors.%目的建立更敏感的检测人免疫缺陷病毒(HIV)抗体的方法,并研制检测试剂盒。方法根据HIV-1/2型的基因序列及其所编码氨基酸结构,采用固相法合成了HIV-1型的gp41.1、gp41.2、gp120、p24和HIV-2型的gp36五条多肽,混合包被酶标板作为固相抗原。用辣根过氧化物酶标记以上多肽抗原作为标记物,建立检测血清中抗HIV-1/2抗体的双抗原夹心ELISA法。同时,

  1. 马流感病毒双抗体夹心ELISA检测方法的建立%Development of Double Antibody Sandwich ELISA for Detection of Equine Influenza Virus

    Institute of Scientific and Technical Information of China (English)

    姬媛媛; 郭巍; 王晓钧; 王征; 卢刚; 赵立平; 李红梅; 相文华

    2011-01-01

    To develop a rapid and effective method for Equine influenza virus (EIV) detection,polyclonal antibodies against EIV A/equine/Xinjiang/07 strain and monoclonal antibody against NP of EIV were generated respectively. Then a double antibody sandwich ELISA (DAS-ELISA)was developed. The specificity of the optimized DAS-ELISA was evaluated using EIV, Equine arteritis virus, Equine herpes virus-1, Equine herpes virus-4 and Japanese encephalitis virus, resulting in only EIV specimens yielding a strong signal. Compared with hemagglutination test, its sensitivity was as two point five to ten times as the later. And it had cross-reactivity with H7N7 subtype. Meanwhile it is suitable for detection of virus from the nasal swabs of experimentally infected equines. The results revealed that the ELISA possessed good specificity and higher sensitivity, indicating a suitable method for rapid detection of EIV.%为建立一种快速、有效的检测马流感病毒(Equine influenza virus,EIV)的方法,以EIV中国分离株A/马/新疆/07(H3N8)制备的多克隆抗体为捕获抗体,原核表达的核蛋白(NP)制备的单克隆抗体为检测抗体,在国内首次建立了检测EIV的双抗体夹心ELISA方法.用该检测方法分别检测EIV、马动脉炎病毒、马疱疹病毒1型、马疱疹病毒4型和马乙型脑炎病毒阳性样品.结果表明,该ELISA方法具有良好的特异性;与常规检测EIV的血凝试验相比,其敏感性是后者的2.5~10倍;同时与H7N7亚型EIV有交叉反应.攻毒试验结果表明该方法可有效检测鼻腔分泌物中的EIV.该方法的建立为EIV的检测及早期防控提供了有效工具.

  2. Development of Double Antibody Sandwich ELISA for Vibrio TDH-VVC-VMHA Fusion Protein%弧菌融合蛋白TDH-VVC-VMHA双抗体夹心ELISA检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    刘秀萍; 王铁良; 唐峰

    2011-01-01

    In order to improve the detection speed and efficiency, a double antibody sandwich ELISA was developed to detect Vibrio parahaemolyticus, Vibrio vulnificus or Vibrio minicus in food simultaneously. The cytorrhyctes of the fusion protein were purified by the electroeluting to immunize cavia cobaya, anti-serum were uesed as capture antibody,goat anti-guinea pig IgG/HRP were uesed as labelled-antibody, optimizing condition was determined by use of the chessboard titration method. The results showed that, the double antibody sandwich ELISA having obvious positive reaction with the culture supernatant of Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio mimicus, but no positive reaction with 8 other culture supernatant of contrast strains including Pseudomonas aeruginosa, Staphylococcus aureus, Listeria, etc. It indicated that this method could be used to detect Vibrio parahaemolyticus, Vibrio vulnificus and V. Mimicus toxin in food simultaneously.%为提高食品中副溶血孤菌、创伤弧菌和拟态弧菌毒素初筛的速度与效率,建立了双抗体夹心ELISA检测方法.以融合蛋白TDH-VVC-VMHA包涵体为抗原免疫豚鼠,采用豚鼠抗融合蛋白免疫血清为包被抗体,辣根过氧化物酶(HRP)标记羊抗豚鼠IgG为标记抗体,应用棋盘滴定法确定ELISA的最适条件.结果表明,所建立的方法与副溶血弧菌、创伤弧菌、拟态弧菌的培养物上清有较明显的阳性反应,与绿脓杆菌、金黄色葡菌球菌、李氏杆菌、甲型副伤寒沙门氏菌、猪霍乱沙门氏菌等5种非弧菌属食物中毒菌培养物上清未见交叉反应,与溶藻弧菌、河流弧菌和麦氏弧菌等3种弧菌培养物上清也未见交叉反应.这说明,该方法可以用于食品中副溶血弧菌、创伤弧菌和拟态弧菌毒素的快速同步免疫学检测.

  3. Development of a double antibody sandwich ELISA for detection of infectious pancreatic necrosis virus%传染性胰坏死病毒双抗体夹心 ELISA检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    张琳琳; 刘敏; 连科迅; 张英; 蒋烨; 姜艳萍; 崔文; 乔薪瑗; 唐丽杰; 李一经

    2014-01-01

    A double-antibody sandwich ELISA ( DAS-ELISA) was developed using purified polyclonal antibody and mono-clonal antibody ( MAb) against viral infectious pancreatic necrosis virus ( IPNV) VP2 protein as capture and detector anti-body, respectively.The optimized reaction conditions included coating with 100μL/well of purified polyclonal antibody at concentration of 1.28 μg/mL, probing with the working concentration of 1.34 μg/mL IgG from the MAb diluting HRP-conjugated antibody with the proportion of 1∶2 000 and judging with P/N>2 and OD490 nm =0.101 494 as positive criteria. The DAS-ELISA was specific detection of IPNV , but no cross-reaction with IHNV, VHSV, SVCV, HRV and inter-assay coefficient of variability were within 10%.In addition, a total of 41 livers of rainbow trout samples were tested by the DAS-ELISA and PT-PCR, and the coincidence was 97%between DAS-ELISA and PT-PCR.These data demonstrated that the DAS-ELISA was specific and sensitive , and provided a useful tool for diagnosis of IPNV infection .%以纯化的兔抗传染性胰坏死病病毒( IPNV) VP2重组蛋白多克隆抗体为包被抗体,抗IPNV VP2单克隆抗体为检测抗体建立了IPNV双抗体夹心ELISA方法。优化反应条件为:兔抗IPNV VP2重组蛋白多克隆抗体包被浓度为1.28μg/mL,抗IPNV VP2单克隆抗体的工作浓度为1.34μg/mL,酶标二抗稀释比例为1∶2000,以P/N>2,且OD490 nm >0.101494作为阳性判定标准。该方法的重复性变异系数均小于10%,与传染性造血器官坏死病毒(IHNV)、病毒性出血败血症病毒(VHSV)、鲤春病毒血症病毒(SVCV)、轮状病毒(HRV)无交叉反应。对41份虹鳟肝脏样品分别进行双抗体夹心ELISA和RT-PCR检测,结果双抗体夹心法与RT-PCR法检测符合率为97%,表明本实验建立的双抗体夹心ELISA检测方法检测IPNV具有较高的敏感性和特异性,可用于IPNV的病原学检测。

  4. Dimers of nineteen-electron sandwich compounds: Crystal and electronic structures, and comparison of reducing strengths

    KAUST Repository

    Mohapatra, Swagat Kumar

    2014-10-03

    The dimers of some Group 8 metal cyclopentadienyl/ arene complexes and Group 9 metallocenes can be handled in air, yet are strongly reducing, making them useful n-dopants in organic electronics. In this work, the Xray molecular structures are shown to resemble those of Group 8 metal cyclopentadienyl/pentadienyl or Group 9 metal cyclopentadienyl/diene model compounds. Compared to those of the model compounds, the DFT HOMOs of the dimers are significantly destabilized by interactions between the metal and the central C-C σ-bonding orbital, accounting for the facile oxidation of the dimers. The lengths of these C-C bonds (X-ray or DFT) do not correlate with DFT dissociation energies, the latter depending strongly on the monomer stabilities. Ru and Ir monomers are more reducing than their Fe and Rh analogues, but the corresponding dimers also exhibit much higher dissociation energies, so the estimated monomer cation/neutral dimer potentials are, with the exception of that of [RhCp2]2, rather similar (-1.97 to-2.15 V vs. FeCp2 +/0 in THF). The consequences of the variations in bond strength and redox potentials for the reactivity of the dimers are discussed.

  5. 牛初乳中sIgA双抗夹心ELISA检测方法的建立%Establishment of a sandwich ELISA for quantitive measurement of sIgA

    Institute of Scientific and Technical Information of China (English)

    朱洪艳; 赵红宇; 周盛华; 高学军

    2011-01-01

    为定量检测牛初乳中sIgA,建立双抗夹ELISA方法.以牛初乳中sIgA为抗原,免疫新西兰白兔,制得抗血清,经纯化后作为包被抗体;利用简易过碘酸钠法对兔抗牛sIgA标记辣根过氧化物酶(HTP),制得酶标抗体;通过方阵滴定法确定ELISA最佳工作条件;进行特异性、重复性、稳定性实验并且检测牛初乳粉样本中的sIgA含量.结果:成功建立了一种定量检测牛初乳中sIgA的双抗夹心ELISA方法.该方法线性范围:15.625~1 000μg/L;最低检测限(LOD)为15.625μg/L;精密度为:批内CV=4.8%;批间CV=6.5%.%To establish an effective ELISA mathod for the determination of bovine colostrum sIgA.Rabbit was immunized by bovine colostrum sIgA to obtain the antiserum.Useing the purified antiserum as coating antibody.All the anti- sIgA were labeled with horseradish peroxidase by sodium oxidation method, and take the HRP labeled anti- sIgA for labeled antibody.The optimal concentrations of ELISA were defined by titration.For speciticity reproducibility and sensitivity experiment and measured the sIgA levels of bovine colostrum with this assay.Results a sandwich ELISA assay for detecting sIgA in bovine colostrum was established successfully.The assay result was linear over a concentration range of 15.625~1 000 μg/L with a limit of detection(LOD) of 15.625 μg/L.The coefficients of variation was 4.8% within assay and 6.5% between assay.

  6. Structure and electronic properties of bilayer graphene functionalized with half-sandwiched transition metal-cyclopentadienyl complexes.

    Science.gov (United States)

    Yao, Xiaojing; Zhang, Xiuyun; Ye, Xiaoshan; Wang, Jinlan

    2016-08-10

    Tuning the electronic and magnetic properties of graphene is a crucial problem in the design of practical on-off electronic devices. Using density functional theory calculations, we explore the electronic and magnetic properties of bilayer graphene functionalized by cyclopentadienyl (Cp = cyclopentadienyl, C5H5) based half-sandwich ligands, CpTM (TM = Sc-Ni). It is found that the adsorption of CpTM ligands can introduce high magnetic moments and open the band gap of bilayer graphene, due to the electron doping as well as the asymmetric charge distribution between two graphene layers. Furthermore, the p-n doping of bilayer graphene by co-binding F/NO2 and CpTM on two external sides of BLG can further widen the band gap up to 366.1 meV. This study proposes an effective way to the modulation of the electronic and magnetic properties of graphene.

  7. 检测百日咳毒素的双抗体夹心ELISA法的建立%Establishment of a double antibody sandwich ELISA method for determination of pertussis toxin

    Institute of Scientific and Technical Information of China (English)

    潘殊男; 肖詹蓉; 张霖阳; 史雨舟; 简志华; 王宇星; 李世慧; 张萍

    2012-01-01

    目的 建立白喉-破伤风-无细胞百日咳疫苗生产中百日咳毒素(pertussis toxin,PT)含量的测定方法.方法 免疫家兔制备高效价抗PT血清,纯化抗PT多克隆抗体并进行酶标记,建立双抗体夹心ELISA法并对其进行验证.结果 建立的方法在0~ 20 ng/ml PT测量区间呈现最佳线性,相关系数>0.99,且重复性好.检测百日咳丝状血凝素和黏着素,结果均为阴性,说明该法特异性良好.试验内10次、不同试验间3次测定16.0、8.0、4.0、3.0 ng/ml PT,变异系数为2.8%~9.7%,回收率为95.7%~106.0%,精密度和准确度验证均符合常规质量控制要求,定量限度为3.0 ng/ml.结论 该方法能有效检测百日咳杆菌大罐发酵过程中分泌的PT,为PT质量控制奠定了重要基础.%Objective To develop an ELISA method for quantitative determination of pertussis toxin (PT) during production of combined diphtheria,tetanus and acellular pertussis vaccine.Methods After chinchilla rabbits were immunized by PT,high titer anti-serum against PT was obtained and polyclonal antibody against PT was prepared.Then,a double antibody sandwich ELISA method was developed and verified.Results The best linearity ranged from 0 to 20 ng/ml of PT (correlation coefficient > 0.99).No cross reactions with filamentous hemagglutinin and pertactin were observed by the developed ELISA.The variation coefficients of intra-and inter-assays were 2.8%-9.7% and the recovery rates were 95.7%-106.0% when 16.0,8.0,4.0 and 3.0 ng/ml of standard PTs were determined.The quantitative limit was identified as 3.0 ng/ml.Conclusion Due to the excellent specificity,precision,and accuracy,this method can be applied to detecting PT in fermentation broth quantitatively.

  8. Sandwich-dot enzyme-linked immunosorbent assay for the detection of canine distemper virus.

    Science.gov (United States)

    Li, Zhi; Zhang, Yanlong; Wang, Huiguo; Jin, Jinhua; Li, Wenzhe

    2013-10-01

    A sandwich-dot enzyme-linked immunosorbent assay (dot ELISA) was developed for the detection of canine distemper virus (CDV). In 56 dogs suspected to have CD the rates of detection of CDV antigen in samples of blood lymphocytes and palpebral conjunctiva by dot ELISA and ELISA were, respectively, 91% (49/54) and 81% (44/54) for the lymphocyte samples and 88% (28/32) and 75% (24/32) for the conjunctival samples. The CDV detection limits were 10 ng/50 μL for dot ELISA and 40 ng/50 μL for ELISA. The reliability of dot ELISA relative to electron microscopy was 96% with 22 samples: all 21 samples in which CDV particles were observed by electron microscopy yielded positive results with dot ELISA; the single sample in which particles were not observed yielded false-positive results with dot ELISA. The results indicate that the dot ELISA developed can serve as a reliable rapid diagnostic test in suspected cases of CD and also be useful for epidemiologic surveillance of the disease.

  9. Preparation of polyclonal antibodies against pneumococcal serotype 1 capsular polysaccharide and development a sandwich ELISA in determination of concentration for type 1 capsular polysaccharide%肺炎球菌1型荚膜多糖多克隆抗体制备与夹心ELISA 法建立及其在多糖浓度测定中的应用

    Institute of Scientific and Technical Information of China (English)

    刘威; 廖红梅; 谢谦; 黄放; 邹莎莎; 马诚; 江山; 崔长法

    2013-01-01

    Objective To prepare polyclonal antibodies against capsular polysaccharide of pneumococcal serotype 1, and use the antibodies to develop a sandwich ELISA in determination of concentration for pneumococcal capsular polysaccharide of serotype 1 in the process of fermentation and purification .Methods High titer serum of anti-capsular polysaccharide se-rotype 1 was obtained after immunizing rabbits by using of inactivated streptococcus pneumoniae cells of serotype 1 for 6 weeks.IgG was purified through affinity chromatography and used as a coating antibody .Polysaccharide samples , alone with in house polysaccharide standard , were then added followed by using biotinylated antibody as a signal antibody .The optimal linear range of the standard curve , specificity, accuracy and precision of the developed method were validated accordingly.Results The antibody titer of rabbit immune serum reached to 1 ∶32, the standard PS1 linear detection range was 1.56 ng/mL to 50 ng/mL, detection limit was 3.13 ng/mL.Standard polysaccharide was mixed with polysaccha-rides from different serotypes or culture media before asssay , the recovery ratio was 102%and 108%respectively .Intra-as-say precision and inter precision of the method were 6.08%and 7.01%.Conclusion High titer rabbit anti-serum against type 1 capsular polysaccharide of streptococcal pneumoniae was prepared .The developed sandwich ELISA method showed high specificity , good accuracy and precision .This method can be used in specific detection of concentration for pneumo-coccal polysaccharide serotype1 .%目的:利用肺炎球菌1型全菌体制备多克隆抗体,并且利用该抗体建立肺炎1型荚膜多糖夹心酶联免疫吸附分析法( Enzyme-linked immunosorbent assay ,ELISA),用于检测发酵和纯化过程中的多糖浓度。方法用灭活的1型肺炎链球菌免疫家兔6周,获得高滴度的抗多糖血清,经过亲和层析纯化,获得高纯度的兔抗肺炎1型多糖

  10. Electronic phase transitions under hydrostatic pressure in LaMnO3 (111) bilayers sandwiched between LaAlO3

    KAUST Repository

    Tahini, Hassan Ali

    2016-01-13

    Using ab initio calculations, we investigate the effect of hydrostatic pressure on the electronic structure of LaMnO3 (111) bilayers sandwiched between LaAlO3. In the ideal heterostructure we observe Dirac cones at the Fermi energy. However, octahedral tiltings open a band gap and thus destroy the Dirac nature. We show that the effect of the tiltings can be suppressed by hydrostatic pressure from 40 GPa to 60 GPa. At higher pressure further phase transitions are encountered.

  11. Spin-Polarized Electron Injection in Co/Cu/Fe Sandwich Structure

    Institute of Scientific and Technical Information of China (English)

    WANG Shou-Guo; CHEN Yan-Xue; WANG Zhi-He; CHEN Qiang; XIE Shi-Jie; MEI Liang-Mo

    2000-01-01

    A material asymmetry Co/Cu/Fe junction structure has been prepared for studying the spin-polarized electron injection at 77K. The sample performance was demonstrated to be analogous to that of a bipolar transistor. The maximal value of the output pulse voltage between Cu and Fe layers could reach the order of severalμV when the bias current between Co and Cu layers was 10μA. The interface roughness, photograph of material, magnetic loop and injection characteristic curves have been measured. Some important points on this topic have been discussed.

  12. Electronic band structure of a Tl/Sn atomic sandwich on Si(111)

    Science.gov (United States)

    Gruznev, D. V.; Bondarenko, L. V.; Matetskiy, A. V.; Tupchaya, A. Y.; Alekseev, A. A.; Hsing, C. R.; Wei, C. M.; Eremeev, S. V.; Zotov, A. V.; Saranin, A. A.

    2015-01-01

    A two-dimensional compound made of one monolayer of Tl and one monolayer of Sn on Si(111) has been found to have a sandwichlike structure in which the Sn layer (having the milk-stool arrangement) resides on the bulklike terminated Si(111) surface and the Tl layer (having the honeycomb-chained-trimer arrangement) is located above the Sn layer. The electronic band structure of the compound contains two spin-split surface-state bands, of which one is nonmetallic and the other is metallic. Near the Fermi level the metallic band is split with the momentum splitting Δ k∥=0.037 Å-1 and energy splitting Δ EF=167 meV. The steep dispersion of the band when crossing the Fermi level corresponds to an electron velocity of ≈8.5 ×105 m/s, which is comparable to the value reported for graphene. The 2D Fermi contours have almost circular shape with spin texture typical for hexagonal surfaces.

  13. Sandwich Panels

    Directory of Open Access Journals (Sweden)

    N. Ramachandran

    1963-05-01

    Full Text Available This introductory article give an insight into the different methods employed in the construction of Sandwich panels, their limitations and future design application for defence use as a structural element with one of the highest strength-weight ratios yet devised.

  14. Sandwich construction

    Science.gov (United States)

    Marshall, A.

    A form of composites known as structural sandwich construction is presented in terms of materials used, design details for solving edging and attachment problems, and charts of design material analysis. Sandwich construction is used in nearly all commercial airliners and helicopters, and military air and space vehicles, and it is shown that this method can stiffen a structure without causing a weight increase. The facing material can be made of 2024 or 7075 aluminum alloy, titanium, or stainless steel, and the core material can be wood or foam. The properties of paper honeycomb and various aluminum alloy honeycombs are presented. Factors pertaining to adhesive materials are discussed, including products given off during cure, bonding pressure, and adaptability. Design requirements and manufacturing specifications are resolved using numerous suggestions.

  15. Preparation of monoclonal antibodies against bovine viral diarrhea virus and the double antibody sandwich ELISA develpoment%抗牛病毒性腹泻病毒单克隆抗体的制备及双抗夹心ELISA检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    蒋颖; 朱国强; 林燕清; 陶洁; 孟祥升; 段小丽; 王娟; 王银; 张信军; 王建业

    2012-01-01

    为建立牛病毒性腹泻病毒(BVDV)双抗夹心ELISA检测方法,本研究将BVDV 890病毒株(BVDV-2)浓缩并纯化后免疫BALB/c小鼠,经常规技术进行细胞融合并筛选得到一株稳定分泌IgG的杂交瘤细胞株,命名为3F9.以BVDV单克隆抗体(MAb) IgM为捕获抗体,生物素标记的3F9为检测抗体,初步建立BVDV特异的双抗体夹心ELISA检测方法(BAS-ELISA).采用建立的BAS-ELISA方法检测35份临床病牛血清样品,检出阳性样本13份;与RT-PCR的符合率达到94.29%;表明本研究所建立的BAS-ELISA方法可用于BVDV感染的临床诊断,为BVDV的免疫学研究奠定了基础.%To establish a double monoclonal antibody (MAb)-mediated sandwich ELISA (DAS-ELISA) for detection of bovine viral diarrhea virus (BVDV), the MAb 3D8 (IgM) and biotin-labelled 3F9 (IgG) were used as capture antibody and detection antibody respectively after obtaining a hybridoma cell line stably secreting antibody (3F9). Thirty-five clinically suspected sera samples were detected by this method and the results of 13 samples were positive. Compared with RT-PCR in the paralled experiment with 11 samples positive, the coincidence rate was 94.25%. It is suggested that the DAS-ELISA was a potentially valuable method with high sensitivity and specificity against BVDV.

  16. Inverted-sandwich-type and open-lantern-type dinuclear transition metal complexes: theoretical study of chemical bonds by electronic stress tensor

    CERN Document Server

    Ichikawa, Kazuhide; Kurokawa, Yusaku I; Sakaki, Shigeyoshi; Tachibana, Akitomo

    2011-01-01

    We study the electronic structure of two types of transition metal complexes, the inverted-sandwich-type and open-lantern-type, by the electronic stress tensor. In particular, the bond order b_e measured by the energy density which is defined from the electronic stress tensor is studied and compared with the conventional MO based bond order. We also examine the patterns found in the largest eigenvalue of the stress tensor and corresponding eigenvector field, the "spindle structure" and "pseudo-spindle structure". As for the inverted-sandwich-type complex, our bond order b_e calculation shows that relative strength of the metal-benzene bond among V, Cr and Mn complexes is V > Cr > Mn which is consistent with the MO based bond order. As for the open-lantern-type complex, we find that our energy density based bond order can properly describe the relative strength of Cr--Cr and Mo--Mo bonds by the surface integration of the energy density over the "Lagrange surface" which can take into account the spatial extent ...

  17. Characterization of a Toxocara canis species-specific excretory-secretory antigen (TcES-57) and development of a double sandwich ELISA for diagnosis of visceral larva migrans

    OpenAIRE

    Iddawela, R.D.; R.P.V.J Rajapakse; Perera, N.A.N.D.; Agatsuma, Takeshi

    2007-01-01

    This study describes the isolation of a Toxocara canis species-specific excretory-secretory (ES) antigen and the development of an enzyme-linked immunosorbent assay (ELISA) based on this antigen. Analysis of the ES antigens of T. canis, Toxocara vitulorum, Ascaris lumbricoides and Necator americanus larval antigen was performed by SDS-PAGE followed by western blotting. A 57 kDa T. canis-specific antibody fraction (TcES-57) was identified by western blotting and labelling with anti-Toxocara an...

  18. Experimental and theoretical studies on the electronic properties of vanadium-benzene sandwich cluster anions, V(n)Bz(n+1)- (n = 1-5).

    Science.gov (United States)

    Masubuchi, Tsugunosuke; Ohi, Katsuya; Iwasa, Takeshi; Nakajima, Atsushi

    2012-12-14

    Vanadium-benzene cluster anions, V(n)Bz(n+1)(-) (Bz = C(6)H(6)) were generated by laser ablation and supersonic jet methods, and studied using photoelectron spectroscopy. The density functional theory was employed to compute their geometric and electronic structures. It is concluded that the V(n)Bz(n+1)(-) anions exhibit multiple-decker sandwich structures similar to their corresponding neutrals, and the adiabatic electron affinity increases with the cluster size. Our computation shows that the excess electron of the anion occupies the d orbitals of the vanadium atoms and that it is delocalized one-dimensionally. Furthermore, a very large HOMO-LUMO gap difference between majority and minority spin orbitals is observed for both the neutrals and the anions, and the V(n)Bz(n+1)(0∕-) clusters are found to be completely spin-polarized. These facts confirm the possibility of using V(n)Bz(n+1) clusters as spin filters.

  19. n-Doping of organic electronic materials using air-stable organometallics: a mechanistic study of reduction by dimeric sandwich compounds.

    Science.gov (United States)

    Guo, Song; Mohapatra, Swagat K; Romanov, Alexander; Timofeeva, Tatiana V; Hardcastle, Kenneth I; Yesudas, Kada; Risko, Chad; Brédas, Jean-Luc; Marder, Seth R; Barlow, Stephen

    2012-11-12

    Several 19-electron sandwich compounds are known to exist as "2×18-electron" dimers. Recently it has been shown that, despite their air stability in the solid state, some of these dimers act as powerful reductants when co-deposited from either the gas phase or from solution and that this behavior can be useful in n-doping materials for organic electronics, including compounds with moderate electron affinities, such as 6,13-bis[tri(isopropyl)silylethynyl]pentacene (3). This paper addresses the mechanisms by which the dimers of 1,2,3,4,5-pentamethylrhodocene (1 b(2)), (pentamethylcyclopentadienyl)(1,3,5-trialkylbenzene)ruthenium (alkyl=Me, 2 a(2); alkyl=Et, 2 b(2)), and (pentamethylcyclopentadienyl)(benzene)iron (2 c(2)) react with 3 in solution. Vis/NIR and NMR spectroscopy, and X-ray crystallography indicate that the products of these solution reactions are 3(·-) salts of the monomeric sandwich cations. Vis/NIR kinetic studies for the Group 8 dimers are consistent with a mechanism whereby an endergonic electron transfer from the dimer to 3 is followed by rapid cleavage of the dimer cation. NMR crossover experiments with partially deuterated derivatives suggest that the C-C bond in the 1 b(2) dimer is much more readily broken than that in 2 a(2); consistent with this observation, Vis/NIR kinetic measurements suggest that the solution reduction of 3 by 1 b(2) can occur by both the mechanism established for the Group 8 species and by a mechanism in which an endergonic dissociation of the dimer is followed by rapid electron transfer from monomeric 1 b to 3.

  20. Development of a Double-antibody Sandwich ELISA for Detection of Subgroup J Avian Leukosis Virus%J亚群禽白血病病毒双抗体夹心ELISA检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    廖亚琳; 梁艺瑜; 王秀珑; 冯敏; 谭利强; 曹伟胜

    2013-01-01

    本研究利用J亚群禽白血病病毒(subgroup J avian leukosis virus,ALV-J)gp85单因子血清纯化后的抗体成功建立了检测ALV-J抗原的双抗体夹心ELISA方法(DAS-ELISA).结果表明,该方法具有良好的特异性、重复性和稳定性,对ALV-J抗原的最小检出量为0.165 μg/mL.用该法对48份临床血浆样品进行检测,结果与PCR方法的符合率达到85.2%.

  1. Biotin-avidin sandwich elisa with specific human isotypes IgG1 and IgG4 for Culicidae mosquito blood meal identification from an epizootic yellow fever area in Brazil

    Directory of Open Access Journals (Sweden)

    AM Marassá

    2009-01-01

    Full Text Available With a view toward investigating the feeding behavior of Culicidae mosquitoes from an area of epizootic yellow fever transmission in the municipalities of Garruchos and Santo Antônio das Missões, Rio Grande do Sul State, Brazil, specimens were collected by aspiration from September 2005 to April 2007. The engorged females were submitted to blood meal identification by enzyme-linked immunosorbent assay (ELISA. A total of 142 blood-engorged samples were examined for human or monkey blood through species-specific IgG. Additional tests for specificity utilizing isotypes IgG1 and IgG4 of human monoclonal antibodies showed that only anti-human IgG1 was effective in recognizing blood meals of human origin. The results indicated a significant difference (p = 0.027 in detection patterns in samples of Haemagogus leucocelaenus recorded from human blood meals at Santo Antônio das Missões, which suggests some degree of exposure, since it was an area where epizootic outbreaks have been reported.

  2. 双抗体夹心ELISA检测HIV-1 gp41抗原方法的建立%Establishment of Antibody-Sandwich ELISA for Detection of HIV-1 gp41 Antigen

    Institute of Scientific and Technical Information of China (English)

    于澜; 徐志凯; 王海涛; 黎志东; 张芳琳

    2006-01-01

    目的:建立检测HIV-1 gp41抗原的双抗体夹心ELISA,并探讨其临床应用的可行性.方法:用饱和硫酸铵(SAS)纯化抗HIV-1 gp41-5单克隆抗体(mAb),用HRP标记后建立双抗体夹心ELISA法,对其灵敏度及特异性进行检测,并用该方法对40份HIV-1阳性血清进行了检测.结果:用mAb E12(5μg/mL)为包被抗体,2H6为酶标记抗体(1:900)建立了双抗体夹心ELISA法,检测gp41-5多肽的灵敏度是100 pg/mL.对HIV-1阳性血清中gp41抗原的检出率为67.5%(27/40).结论:建立了特异性强、灵敏度良好的检测HIV-1 gp41抗原的双抗体夹心ELISA法.

  3. 牛病毒性腹泻病毒双抗体夹心ELISA检测方法的建立%Detection of bovine viral diarrhea virus by sandwich ELISA

    Institute of Scientific and Technical Information of China (English)

    高存福; 秦建华; 赵月兰; 包永占; 张宁

    2005-01-01

    将牛病毒性腹泻病毒超免疫血清以常规方法提取IgG,采用过碘酸钠法标记辣根过氧化物酶(HRP),建立了从粪样中检测牛病毒性腹泻病毒抗原的双抗体夹心ELISA.结果,抗体的最佳包被量为150μg/mL,酶标抗体最适工作浓度为1∶200;封闭液为50mL/L的兔血清;待检粪样及酶标抗体的感作时间为37℃ 120min;底物显色时间为室温15min.应用建立的检测方法对河北省8个大中型奶牛场298份乳牛腹泻粪样进行了检测,结果,阳性检出率为42.6%.

  4. Solar hydrogen generation by a CdS-Au-TiO2 sandwich nanorod array enhanced with Au nanoparticle as electron relay and plasmonic photosensitizer.

    Science.gov (United States)

    Li, Jiangtian; Cushing, Scott K; Zheng, Peng; Senty, Tess; Meng, Fanke; Bristow, Alan D; Manivannan, Ayyakkannu; Wu, Nianqiang

    2014-06-11

    This paper presents a sandwich-structured CdS-Au-TiO2 nanorod array as the photoanode in a photoelectrochemical cell (PEC) for hydrogen generation via splitting water. The gold nanoparticles sandwiched between the TiO2 nanorod and the CdS quantum dot (QD) layer play a dual role in enhancing the solar-to-chemical energy conversion efficiency. First, the Au nanoparticles serve as an electron relay, which facilitates the charge transfer between CdS and TiO2 when the CdS QDs are photoexcited by wavelengths shorter than 525 nm. Second, the Au nanoparticles act as a plasmonic photosensitizer, which enables the solar-to-hydrogen conversion at wavelengths longer than the band edge of CdS, extending the photoconversion wavelength from 525 to 725 nm. The dual role of Au leads to a photocurrent of 4.07 mA/cm(2) at 0 V (vs Ag|AgCl) under full solar spectrum irradiation and a maximum solar-to-chemical energy conversion efficiency of 2.8%. An inversion analysis is applied to the transient absorption spectroscopy data, tracking the transfer of electrons and holes in the heterostructure, relating the relaxation dynamics to the underlying coupled rate equation and revealing that trap-state Auger recombination is a dominant factor in interfacial charge transfer. It is found that addition of Au nanoparticles increases the charge-transfer lifetime, reduces the trap-state Auger rate, suppresses the long-time scale back transfer, and partially compensates the negative effects of the surface trap states. Finally, the plasmonic energy-transfer mechanism is identified as direct transfer of the plasmonic hot carriers, and the interfacial Schottky barrier height is shown to modulate the plasmonic hot electron transfer and back transfer. Transient absorption characterization of the charge transfer shows defect states cannot be ignored when designing QD-sensitized solar cells. This facile sandwich structure combines both the electrical and the optical functions of Au nanoparticles into a

  5. Thermal-Diode Sandwich Panel

    Science.gov (United States)

    Basiulis, A.

    1986-01-01

    Thermal diode sandwich panel transfers heat in one direction, but when heat load reversed, switches off and acts as thermal insulator. Proposed to control temperature in spacecraft and in supersonic missiles to protect internal electronics. In combination with conventional heat pipes, used in solar panels and other heat-sensitive systems.

  6. Sandwich DIY

    Institute of Scientific and Technical Information of China (English)

    肖蕾

    2006-01-01

    我们都知道sandwich是一种方便食品,就是在两片面包中加上一些肉和蔬菜。Sandwich这个名字来源于英国的一位桑威治伯爵(Earl of Sandwich)。据说这位伯爵嗜赌如命,就是到吃饭的时候也不愿停下来。于是他就叫侍者把肉、蛋、菜夹在面包片中,让他拿在手上边赌边吃。后来人们就把这种夹馅面包叫做sandwich。现在sandwich已成为风靡世界的快餐食品(snack)了。Sandwich的做法其实很简单。如果你有两片面包,你几乎可以在这两片面包之间夹上任何食物来给自己做一个三明治。下面就让我们试一试,做一个三明治来吃。第一步:在一片面包上抹上黄油(butter)或植物黄油,在另一片面包上抹上蛋黄酱(mayonnaise)和芥末酱(mustard)。喜欢吃番茄酱(catsup)也可以放番茄酱!第二步:把花生酱(peanut butter)或者乳酪片(cream)、熟肉片放在涂了黄油的面包片上。想吃什么肉就放什么肉,香肠也可以!第三步:在乳酪上面放酸黄瓜片、番茄片和生菜。也可以根据个人的口味再放些乳酪、芥末酱和(或)番茄酱、洋葱、辣椒、盐、黑胡椒和醋。第四步:将第二片面包盖在上面,就做成了一个sand...

  7. Variants of ELISA in plant virus diagnosis.

    Science.gov (United States)

    Koenig, R; Paul, H L

    1982-10-01

    Variations of enzyme-linked immunosorbent assay (ELISA) were compared with respect to their ability to detect and to differentiate serologically related plant viruses. The broadest range of serologically related viruses was detected by an indirect ELISA on unprecoated plates. Coating the plates with F(ab')2 fragments led to narrowing of the specificity in heterologous reactions of tymo-, tombus- and tobamoviruses in indirect ELISA. With Andean potato latent virus (APLV) heterologous reactions were weaker on plates precoated with F(ab')2 fragments than on those precoated with intact antibodies. Even on plates precoated with F(ab')2 fragments the indirect ELISA detected a broader range of serologically related viruses than the direct double antibody sandwich method. Heterologous reactions in indirect ELISA procedures on plates precoated with either intact antibodies or F(ab')2 fragments were always weaker than homologous reactions independent of the concentration of coating reactants and detecting antibodies. Attempts to differentiate closely related strains of APLV or radish mosaic virus by direct ELISA using F(ab')2 fragments either for coating the plates or after labelling with alkaline phosphatase for detecting the trapped antigens failed. Under suitable conditions, the additional working step usually necessary for indirect ELISA could be avoided by using a short procedure which at low concentrations of detecting antibodies was more sensitive than the conventional procedure.

  8. Controlling the electronic and geometric structures of 2D insertions to realize high performance metal/insertion-MoS2 sandwich interfaces.

    Science.gov (United States)

    Su, Jie; Feng, Liping; Zeng, Wei; Liu, Zhengtang

    2017-06-08

    Metal/insertion-MoS2 sandwich interfaces are designed to reduce the Schottky barriers at metal-MoS2 interfaces. The effects of geometric and electronic structures of two-dimensional (2D) insertion materials on the contact properties of metal/insertion-MoS2 interfaces are comparatively studied by first-principles calculations. Regardless of the geometric and electronic structures of 2D insertion materials, Fermi level pinning effects and charge scattering at the metal/insertion-MoS2 interface are weakened due to weak interactions between the insertion and MoS2 layers, no gap states and negligible structural deformations for MoS2 layers. The Schottky barriers at metal/insertion-MoS2 interfaces are induced by three interface dipoles and four potential steps that are determined by the charge transfers and structural deformations of 2D insertion materials. The lower the electron affinities of 2D insertion materials, the more are the electrons lost from the Sc surface, resulting in lower n-type Schottky barriers at Sc/insertion-MoS2 interfaces. The larger the ionization potentials and the thinner the thicknesses of 2D insertion materials, the fewer are the electrons that accumulate at the Pt surface, leading to lower p-type Schottky barriers at Pt/insertion-MoS2 interfaces. All Sc/insertion-MoS2 interfaces exhibited ohmic characters. The Pt/BN-MoS2 interface exhibits the lowest p-type Schottky barrier of 0.52 eV due to the largest ionization potential (∼6.88 eV) and the thinnest thickness (single atomic layer thickness) of BN. These results in this work are beneficial to understand and design high performance metal/insertion-MoS2 interfaces through 2D insertion materials.

  9. 抗CPV-2a单克隆抗体的制备及双抗体夹心ELISA检测方法的建立%Preparation of Monoclonal Antibody Against CPV-2a and Establishment of Double Antibody Sandwich ELISA Detection Method to CPV-2a

    Institute of Scientific and Technical Information of China (English)

    王净; 李刚; 王鹏; 曾妮; 穆秀明; 高志花; 王慧文; 史利军

    2011-01-01

    The canine parvovirus (CPV) , which is hard to get cured, is one of the most severe diseases in dogs.However, an effective therapeutic method for the CPV is the monoclonal antibody. This article described the approach to the preparation of anti-CPV-2a monoclonal antibody. The canine parvovirus antibodies were prepared from New Zealand rabbit and Balb/c mouse with purified CPV-2a antigen. After subcloned, 4 strains of positive hybridoma cells were obtained, which were named 1H9, 2B5, 2B7 and 2C7 respectively. Their immunoreactivity were identified by Westem blotting and their specificity were done by indirect ELISA. In order to detect the canine parvovirus, a double antibody sandwich ELISA method was established. The assay used rabbit anti-CPV-2a polyclonal antibody as the capture antibody, monoclonal antibody as the trace antibody and goat anti-mouse IgG HRP conjugation as the detection system. The optimal dilution of the capture antibody and the trace antibody capable of detecting the CPV-2a antigens was found to be 1: 800 and 1: 2 000 respectively in the check-board titration, and that of the detection system was 1: 4 000. The result showed that the immunoreaction of the monoclonal antibody with pET-32a-VP2 protein was positive and its reaction with RV or CDV antigen was negative. The detective sensitivity ofsandwich ELISA was 4.375 μg/mL. Compared with RB of USA ELISA kit, the coincidence rate was 95%.The preparation of monoclonal antibody would provide the basis to treat the canine parvovirus. The establishment of double antibody sandwich ELISA method would be a simple, quick and reliable method for screening large numbers of fecal samples of dogs suspected of CPV infection.%犬细小病毒病是危害养犬业的重要传染病之一,患病犬难以治愈.单克隆抗体治疗此病效果明显,本文介绍了制备抗CPV-2a单克隆抗体的方法.用纯化的犬细小病毒(canine parvovirus,CPV) 2a型分离株免疫新西兰大

  10. Ytterbocenes as one- and two-electron reductants in their reactions with diazadienes: YbIII mixed-ligand bent-sandwich complexes containing a dianion of diazabutadiene.

    Science.gov (United States)

    Trifonov, Alexander A; Borovkov, Ivan A; Fedorova, Elena A; Fukin, Georgii K; Larionova, Joulia; Druzhkov, Nikolai O; Cherkasov, Vladimir K

    2007-01-01

    Ytterbocene [Yb(C(5)MeH(4))(2)(thf)(2)] reacts with diazabutadiene 2,6-iPr(2)C(6)H(3)-N=CH-CH=N-C(6)H(3)iPr(2)-2,6 (DAD) as a one-electron reductant to afford a bis(cyclopentadienyl) Yb(III) derivative containing a DAD radical anion [Yb(C(5)MeH(4))(2)(dad(-.))]. However, ytterbocenes [YbCp*(2)(thf)(2)] (Cp*=C(5)Me(5), C(5)Me(4)H) coordinated by sterically demanding cyclopentadienyl ligands act as two-electron reductants in their reactions with DAD. These reactions occur by abstraction of one Cp* ring and result in the formation of novel Yb(III) mixed-ligand bent-sandwich complexes, [YbCp*(dad)(thf)], in which the dianion of DAD has an uncommon terminal eta(4)-coordination to the ytterbium atom. The variable-temperature magnetic measurements of complex [Yb(C(5)Me(5))(dad)(thf)] suggest the existence of redox tautomerism for this compound.

  11. High-resolution electron microscopy and spectroscopy of ferritin in biocompatible graphene liquid cells and graphene sandwiches.

    Science.gov (United States)

    Wang, Canhui; Qiao, Qiao; Shokuhfar, Tolou; Klie, Robert F

    2014-06-04

    Atomic and electronic structures of hydrated ferritin are characterized using electron microscopy and spectroscopy through encapsulation in single layer graphene in a biocompatible manner. Graphene's ability to reduce radiation damage levels to hydrogen bond breakage is demonstrated. A reduction of iron valence from 3+ to 2+ is measured at nanometer-resolution in ferritin, showing initial stages of iron release by ferritin. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Establishment of a sandwich ELISA for quantitative measurement of human supersensitivity C-reactive protein and primary clinical applica-tion study%定量检测人超敏C-反应蛋白双抗体夹心ELISA方法的建立及初步临床应用

    Institute of Scientific and Technical Information of China (English)

    沈丹丹; 卞智萍; 何国平; 顾春荣; 徐晋姚; 杨笛; 张寄南

    2009-01-01

    AIM: To establish a sandwich ELISA for quantitative measurement of supersensitivity C-reac-tive protein(hs-CRP). METHODS: Anti-CRP monoclonal antibodies (mAbs) prepared by our laboratory were purified by Protein A affinity chromatography and analyzed by SDS-PAGE and Western-blotting to test their characteristics. All the mAbs were labeled with horseradish peroxidase by sodium oxidation method and antibody mating test were performed using anti-CRP mAb as coating antibody and HRP labeled anti-CRP mAb as labeled antibody, in which optimal concentrations were defined by square mateix titration. Standard curve was performed using purified CRP and the sensitivity, reproducibility and recovery rate test of ELISA was evaluated. The CRP levels in plasma were measured in this assay. RESULTS: The optimal paired antibodies were anti-CRP mAb 1C10 and HRP labeled anti-CRP mAb 2C11, and the optimal concentrations were 10 μg/mL and 1: 2000,respectively. The coefficient of variation were 3.1% to 9.7 % within assay and 3.6% to 13.6% between assay. The sensitivity in this assay was 8.3 ng/mL. The recovery rate was 90% to 109%. According to the result,68 normal persons' hs-CRP level in plasma of coronary arteriography were detected by ELISA, 59 with stenosis < 50% and 67 with stenosis ≥50%. The results showed that the plasma hs-CRP level in patients with stenosis < 50% (3.65 ± 1.15) mg/L was significantly higher ( P < 0.05)than hs-CRP in normol persons(1.75 ± 0.74) mg/L, the plasma hs-CRP level in stenosis ≥ 50% patients ( 8.93 ± 3.29) mg/L was significantly higher (P < 0.05) than stenosis < 50% patients. CONCLUSION: A sandwich ELISA for detecting hs-CRP was established.%目的:建立定量检测人超敏C-反应蛋白(CRP)双抗体夹心ELISA方法.方法:采用ProteinA亲和层析法纯化本室制备的抗CRP单克隆抗体(mAbs),并行SDS-PAGE和Western blotting对纯化抗体特性进行鉴定;利用简易过碘酸钠法对抗CRP mAbs进行标记HRP后行抗体配对实

  13. Investigation of the electrical properties of a new PPV derivative-based on a sandwich structure for opto-electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Benzarti-Ghedira, Maha; Hrichi, Haikel; Jaballah, Nejmeddine [Laboratoire Interfaces et Materiaux Avances (LIMA), Universite de Monastir, Faculte des Sciences de Monastir, Bd. de l' Environnement, 5019 Monastir (Tunisia); Ben Chaabane, Rafik, E-mail: rafik.benchaabane@fsm.rnu.tn [Laboratoire Interfaces et Materiaux Avances (LIMA), Universite de Monastir, Faculte des Sciences de Monastir, Bd. de l' Environnement, 5019 Monastir (Tunisia); Majdoub, Mustapha; Ben Ouada, Hafedh [Laboratoire Interfaces et Materiaux Avances (LIMA), Universite de Monastir, Faculte des Sciences de Monastir, Bd. de l' Environnement, 5019 Monastir (Tunisia)

    2012-04-01

    The opto-electronic properties of native poly(p-phenylene vinylene) (PPV) were tuned by the confinement of the {pi}-conjugation and the incorporation of a sulphur group as a spacer in order to obtain a blue-green emitting polymer (PPVS). The energy band gap of the PPVS thin film has been measured by UV-vis absorption spectroscopy and evaluated to 2.87 eV. Current-voltage characteristics and impedance spectroscopy measurements performed on sandwich structures [ITO/PPVS/Al] are used to elucidate the conduction mechanisms. The static electrical characterisations showed a space charge limited conduction (SCLC) and a conductivity with low power frequency behaviour characteristic of a hopping transport in disordered materials. The impedance spectra can be discussed in terms of an equivalent circuit model designed as a parallel resistor R{sub P} and capacitor C{sub P} network in series with a resistor R{sub S}. We extract numerical values of these parameters by fitting experimental data. Their evolution with bias voltages has shown that the SCLC mechanism is characterised by an exponential trap distribution.

  14. The sandwich sign

    Directory of Open Access Journals (Sweden)

    Nasreen Mahomed

    2012-09-01

    Full Text Available The sandwich sign refers to the sandwiching of mesenteric vessels and fat by enlarged mesenteric nodes on cross-sectional imaging, commonly occurring in lymphoma, but not specific to lymphoma. The sign is radiologically indistinguishable from post-transplant lymphoproliferative disorders. The radiological significance of the sandwich sign is in suggesting the diagnosis of lymphoma so that appropriate treatment may be initiated early as the tumour has a rapid growth pattern.

  15. The detection of specific immune complex by using double McAb sandwich ELISA in sera of patients with neurocysticercosis%双单抗夹心ELISA法检测脑囊尾蚴病血清特异性免疫复合物

    Institute of Scientific and Technical Information of China (English)

    张明霞; 林尔昕; 王淑民; 崔琢

    2001-01-01

    Objective:To develop a double monoclonal an tibody sandwich ELISA assay for detecting specific immune complex(IC) in sera of patients with neurocysticercosis.Methods:Anti-human IgG McAb was employed as coat,and HRP labeled an ti-cysticerci McAb as recognizing system to detect antibody specific IC.Results:The IC positive rate was found in 53.3% of patients(P <0.005).By using the new method to detect three different kinds of serological markers,the results showed the IC positive rates for group of CAg(-) and CAb(-) was 50%(P<0.005).The IC detection rate was higher than CAg's(P<0. 005).Conclusions:It suggests that detection of IC is of significance in i mproving diagnosis in neurocysticercosis,especially with CAg(-) and CAb(-).%目的:建立双单抗夹心酶联免疫吸附试验法检测脑囊尾蚴病患者血清中特异性免疫复合物。方法:用抗人IgG单抗包被,捕获血清中特异性IgG型免疫复合物,通过酶标抗囊尾蚴单抗结合物显色,测其OD值。结果:用本方法测得患者特异性免疫复合物阳性率为53.3%,明显高于正常对照组(P<0.005);循环抗原、抗体皆阴性患者,免疫复合物的阳性率为50%,与各组相比差异有显著性(P<0.005);且免疫复合物的检出率明显高于循环抗原的检出率( P<0.005)。结论:本法对囊尾蚴病的诊断有重要的临床价值,尤其对抗原、抗体皆阴性患者意义更大。

  16. Evaluation of measurement of human TNF in plasma by ELISA.

    Science.gov (United States)

    Engelberts, I; Möller, A; Schoen, G J; van der Linden, C J; Buurman, W A

    1991-04-01

    The performance of a sandwich-ELISA for TNF measurement in plasma and serum was studied. The ELISA was first statistically analyzed. Interassay coefficient of variance and the intraassay coefficient of variance for the concentration range between 0.5 and 5 ng/ml was less than 10%. The sensitivity of the sandwich-ELISA for TNF in culture medium was 10 pg/ml. The ELISA was shown to be specific for biologically active TNF, since a good correlation between the ELISA and the WEHI bioassay was observed when partially inactive, denatured TNF was measured. The effect of various anticoagulation systems on the reliability of human TNF measurement has been evaluated. The oxalate/NaF and EDTA systems were both appropriate, as appeared from the observed blockade of the production of TNF in the tube, either in the cell-glycolysis-blocked or in the calcium-depleted situation, respectively. An eventual decrease in the recovery of rTNF after collection of blood was prevented in the oxalate/NaF tubes. Recovery of TNF in the ELISA was diminished in the presence of plasma or serum. Techniques to enhance the efficiency of the measurement of TNF in plasma by ELISA were compared. The data indicate that in the presence of 1.1 M NaCl, the TNF masking effect of normal plasma was largely abrogated. The presence and role of inhibiting plasma components in plasma of healthy and diseased individuals are discussed.

  17. Dielectric spectroscopy of electron beam deposited yttrium oxide films examined in metal–insulator–metal sandwich type structures

    Energy Technology Data Exchange (ETDEWEB)

    Wiktorczyk, Tadeusz, E-mail: Tadeusz.Wiktorczyk@pwr.wroc.pl; Biegański, Piotr

    2014-01-31

    This report describes the dielectric properties of electron-beam deposited Y{sub 2}O{sub 3} thin films examined in metal–insulator–metal-type structures fabricated onto quartz substrates. The dielectric measurements have been carried out in the frequency domain from 10 mHz to 10 MHz, with a frequency response analyser. Frequency characteristics of the complex capacitance, as well as Cole–Cole and Nyquist graphs, have been presented and discussed for the temperature range 398–523 K. The results have been analyzed in terms of equivalent circuit models containing resistance–capacitance and constant phase elements (CPE). We have determined the values of the resistance, capacitance and CPE, which characterize the Y{sub 2}O{sub 3} film and near-electrode regions. It has been shown that for high frequencies/low temperatures the dielectric properties are connected with Y{sub 2}O{sub 3} film, while for low frequencies/high temperatures the dielectric response is dominated by the near-electrode regions. In the frequency range 0.1–10 MHz the important contribution of series resistance of electrodes and leads has been observed. - Highlights: • We examine the Al/Y{sub 2}O{sub 3}/Al thin film capacitors for frequency range 10 mHz–10 MHz. • The dielectric data are assigned to Y{sub 2}O{sub 3} and to metal/insulator interfaces. • The capacitance, resistance and constant phase elements describe their properties. • The values of these elements are estimated for temperatures from 398 K to 523 K.

  18. ELISA u analitici hrane

    OpenAIRE

    Runje, Mislav; Cvrtila, Željka

    2006-01-01

    U radu su prikazane neke od mogućnosti korištenja “screening” testa ELISA u analitici namirnica. Utvrđivanje vrsta mesa u toplinski obrađenim ili, pak, toplinski neobrađenim proizvodima jedna je od primjena ELISA testova.

  19. Sandwich classification theorem

    Directory of Open Access Journals (Sweden)

    Alexey Stepanov

    2015-09-01

    Full Text Available The present note arises from the author's talk at the conference ``Ischia Group Theory 2014''. For subgroups FleN of a group G denote by Lat(F,N the set of all subgroups of N , containing F . Let D be a subgroup of G . In this note we study the lattice LL=Lat(D,G and the lattice LL ′ of subgroups of G , normalized by D . We say that LL satisfies sandwich classification theorem if LL splits into a disjoint union of sandwiches Lat(F,N G (F over all subgroups F such that the normal closure of D in F coincides with F . Here N G (F denotes the normalizer of F in G . A similar notion of sandwich classification is introduced for the lattice LL ′ . If D is perfect, i.,e. coincides with its commutator subgroup, then it turns out that sandwich classification theorem for LL and LL ′ are equivalent. We also show how to find basic subroup F of sandwiches for LL ′ and review sandwich classification theorems in algebraic groups over rings.

  20. Comparative Study of Three Different ELISA to Measure the Antibodies Against Infectious Bronchitis Virus in Vaccinated and Unvaccinated Broilers

    OpenAIRE

    Cardoso TC; Oliveira. C.; SEL Da-Silva; HL Ferreira; Pinto AA

    2001-01-01

    Broilers were spray-vaccinated (n=150) with H120 serotype at one-day-old, challenged after 28 days with M41 IBV serotype and after bled at day 28, 34 and 46 after challenged. The respective sera were tested by the indirect ELISA (I-ELISA), sandwich ELISA (S-ELISA), liquid phase blocking ELISA (LPB-ELISA) and the standard serum neutralization test (SNT). For this purpose, a total of 300 sera samples, 150 from non vaccinated and 150 from vaccinated broilers were titrated by all the serological ...

  1. An ELISA for the quantitation of von Willebrand Factor

    DEFF Research Database (Denmark)

    Vinholt, Pernille Just; Overgaard, Martin; Diederichsen, Axel Cosmus Pyndt;

    2013-01-01

    with and without documented coronary calcification (total n=118). RESULTS AND CONCLUSIONS: The assay detected VWF:OPG complexes in human plasma, while no significant signal was observed when testing solutions containing VWF or recombinant OPG alone. Importantly, the ELISA assay was able to detect in vitro formed...... for measurement of von Willebrand factor-osteoprotegerin complex (VWF:OPG) in human plasma. Furthermore, the significance of VWF:OPG complex as a marker of cardiovascular disease (CVD) was evaluated. PATIENTS/METHODS: A sandwich ELISA for quantification of VWF:OPG was developed using a polyclonal rabbit anti...

  2. Predicting safe sandwich production

    DEFF Research Database (Denmark)

    Birk, Tina; Duan, Zhi; Møller, Cleide Oliveira de Almeida

    2014-01-01

    and serving. However, Danish sandwich producing companies find it challenging to comply with this and have expressed a need for more flexibility. The Danish guidelines do allow for a prolongation of the acceptable time outside the cold chain, if the safety of the specific production can be documented....... There is, therefore, room for developing targeted tools for evaluating the time-temperature scenarios in sandwich production. This study describes a decision support tool developed to offer the producers more flexibility. Based on time/temperature measurements obtained during preparation combined......Time and temperature control is crucial to avoid growth of pathogens during production and serving of cold ready-to-eat meals. The Danish guidelines state that chilled foods, such as sandwiches, should not be outside the cold chain for more than 3 hours including the time for preparation...

  3. Comparative Study of Three Different ELISA to Measure the Antibodies Against Infectious Bronchitis Virus in Vaccinated and Unvaccinated Broilers

    Directory of Open Access Journals (Sweden)

    Cardoso TC

    2001-01-01

    Full Text Available Broilers were spray-vaccinated (n=150 with H120 serotype at one-day-old, challenged after 28 days with M41 IBV serotype and after bled at day 28, 34 and 46 after challenged. The respective sera were tested by the indirect ELISA (I-ELISA, sandwich ELISA (S-ELISA, liquid phase blocking ELISA (LPB-ELISA and the standard serum neutralization test (SNT. For this purpose, a total of 300 sera samples, 150 from non vaccinated and 150 from vaccinated broilers were titrated by all the serological methods and the correlation coefficients were determined. The correlation values (r between LPB-ELISA x SNT, S-ELISA x SNT, I-ELISA x SNT found werer = 0.98, r = 0.79, and r = 0.74, respectively. Nevertheless, the r between LPB-ELISA x S-ELISA, LPB-ELISA x I-ELISA and S-ELISA x I-ELISA were r = 0.75, r = 0.69 and r = 0.79. In fact , the I-ELISA and the S-ELISA had almost the same correlation with S-ELISA and LPB-ELISA, in contrast with the I-ELISA and LPB-ELISA. It was concluded that LPB-ELISA showed better sensitivity than I-ELISA and S-ELISA, also after 46 days challenge with the heterologous serotype. However, these two last techniques demonstrated similar specificity when the titers were compared with those obtained in SNT, even though after the heterologous serotype challenge the SNT produced better results. This study demonstrated the close relationship between LPB-ELISA and SNT assays.

  4. On Sandwiched Singularities

    OpenAIRE

    Möhring, Konrad

    2004-01-01

    Sandwich-Singularitäten sind die Singularitäten auf derNormalisierung von Aufblasungen eines regulärenFlächenkeimes. In der Arbeit wird ein enger Zusammenhangzwischen Topologie und Deformationstheorie vonSandwich-Singularitäten einerseits und ebenenKurvensingularitäten andererseits dargestellt. NeueErgebnisse betreffen u.a. Deformationen vonnulldimensionalen komplexen Räumen in der Ebene, die durchvollständige Ideale beschrieben werden, z.B. wann'simultanes Aufblasen' der Fasern einer solchen...

  5. Preparation of double-antibody and establishment of sandwich ELISA against milk β-casein and soybeanβ-conglycinin . Journal of Zhejiang University (Agric . & Life Sci .), 2013,39(2):222-226%牛奶β-酪蛋白和大豆β-伴球蛋白双抗制备及夹心ELISA快速定性检测技术的建立

    Institute of Scientific and Technical Information of China (English)

    肖海龙; 赵凯; 林赛君; 王红青; 潘建红

    2013-01-01

    Summary Protein adulteration and allergens are the two major food safety issues , and can pose health threats to consumers . One of the effective precautions is extensive test , which needs simple , rapid and low‐cost test method . Present methods including sodium dodecyl sulfate polyacrylamide gel electrophoresis ( SDS‐PAGE) , high performance liquid chromatography ( HPLC) and liquid chromatography‐mass spectrometry ( LC‐MS)/MS are not acceptable for consumers due to expensive instruments . Immunological technique is a rapid method for screening and is suitable for consumers to use .β‐casein andβ‐conglycinin are not only the major proteins of milk and soybean , but also important food borne allergens . In this study , the monoclonal antibodies and polyclonal antibodies against β‐casein and β‐conglycinin were prepared and the enzyme‐linked immunosorbent assay ( ELISA ) kits were established for detecting adulteration and allergens . BALB/c mice were immunized four times with purified antigens adding adjuvant or not until the serum titer achieved 1∶1 × 105 , and the mice spleen cells and myeloma cells SP2/0 were fused as the routine cell‐fusion technology . Positive cells were screened for 3‐4 times with indirect ELISA by coating purified antigens , and were injected into mice peritoneal . The monoclonal antibodies were obtained after the purification of ascites . The polyclonal antibodies against β‐casein and β‐conglycinin were also prepared from rabbit serum immunized by antigens , respectively . The double antibody sandwich ELISA for β‐casein and β‐conglycinin were successfully established by optimized parameters . The results showed that the titers of purified monoclonal antibodies of β‐casein and β‐conglycinin were over 1∶1 × 107 , and the polyclonal antibody titers of both were about 1∶2 × 105 . The minimum detection limits of both ELISA kits were about 15 ng/mL , and no cross reaction were observed among

  6. Origin of Sandwich

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    In every language there are words that have some interesting stories behind them. The word “sandwich” forexample, is very common in English. If we want to know the story behind it, we must know something about an English nobleman named Sandwich who lived in the 18th century.

  7. Making a Sandwich

    Institute of Scientific and Technical Information of China (English)

    郭富强

    2011-01-01

    Do you like eating sandwiches? Here is a recipe(做法) for a fruit sandwich.First , you should put butter(黄油)on two slices(片) of bread. Next, peel(剥开) three bananas. Now cut up(切碎) these three bananas and apple.

  8. Cornelius Elisa Bertus Bremekamp

    NARCIS (Netherlands)

    Lanjouw, J.

    1969-01-01

    Cornelis Elisa Bertus Bremekamp was born at Dordrecht on February 7th 1888. He is therefore now just past eighty, and he has been a member of the Koninklijke Nederlandse Botanische Vereniging for sixty years. He studied at the Utrecht State University and, like many of his contemporaries, was

  9. Sensitive detection of Escherichia coli O157:H7 based on cascade signal amplification in ELISA.

    Science.gov (United States)

    Shan, Shan; Liu, Daofeng; Guo, Qi; Wu, Songsong; Chen, Rui; Luo, Kai; Hu, Liming; Xiong, Yonghua; Lai, Weihua

    2016-09-01

    In this study, cascade signal amplification in ELISA involving double-antibody sandwich ELISA and indirectly competitive ELISA was established to sensitively detect Escherichia coli O157:H7. In the double-antibody sandwich ELISA, a complex was formed comprising anti-E. coli O157:H7 polyclonal antibody, E. coli O157:H7, biotinylated anti-E. coli O157:H7 monoclonal antibody, streptavidin, and biotinylated β-lactamase. Penicillin solution was then added into the ELISA well and hydrolyzed by β-lactamase. Afterward, the penicillin solution was transferred to indirectly competitive ELISA. The concentration of penicillin can be sensitively detected in indirectly competitive ELISA. In the cascade signal amplification system, increasing the amount of added E. coli O157:H7 resulted in more β-lactamase and less penicillin. The detection sensitivity of E. coli O157:H7, which was 20cfu/mL with the cascade signal amplification in ELISA, was 1,000-fold higher than that of traditional ELISA. Furthermore, the novel method can be used to detect E. coli O157:H7 in milk (2cfu/g). Therefore, this new signaling strategy will facilitate analyses of highly sensitive foodborne pathogens.

  10. A short history, principles, and types of ELISA, and our laboratory experience with peptide/protein analyses using ELISA.

    Science.gov (United States)

    Aydin, Suleyman

    2015-10-01

    Playing a critical role in the metabolic homeostasis of living systems, the circulating concentrations of peptides/proteins are influenced by a variety of patho-physiological events. These peptide/protein concentrations in biological fluids are measured using various methods, the most common of which is enzymatic immunoassay EIA/ELISA and which guide the clinicians in diagnosing and monitoring diseases that inflict biological systems. All the techniques where enzymes are employed to show antigen-antibody reactions are generally referred to as enzymatic immunoassay EIA/ELISA method. Since the basic principles of EIA and ELISA are the same. The main objective of this review is to present an overview of the historical journey that had led to the invention of EIA/ELISA, an indispensible method for medical and research laboratories, types of ELISA developed after its invention [direct (the first ELISA method invented), indirect, sandwich and competitive methods], problems encountered during peptide/protein analyses (pre-analytical, analytical and post-analytical), rules to be followed to prevent these problems, and our laboratory experience of more than 15 years. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Sandwiched composites in aerospace engineering

    OpenAIRE

    Nunes, J. P.; Silva,J.F.

    2016-01-01

    This chapter considers sandwiched composites used in aerospace applications. Typical sandwich composites consist of two thin, stiff, high-strength facing skins separated by a thick and light core. New developments in the type of face and core materials, production methods and joining and repair techniques are discussed in this chapter. It also discusses various properties as well as their main design methods for existing and future applications of sandwiched composites.

  12. An ELISA for detection of antibodies against influenza A nucleoprotein in humans and various animal species.

    NARCIS (Netherlands)

    G.F. de Boer; W. Back; A.D.M.E. Osterhaus (Albert)

    1990-01-01

    textabstractA double antibody sandwich blocking ELISA, using a monoclonal antibody (MAb) against influenza A nucleoprotein (NP) was developed to detect antibodies against influenza. Collections of serum samples were obtained from human and various animal species. All influenza A subtypes induced ant

  13. Chicken IgY-based coproantigen capture ELISA for diagnosis of human opisthorchiasis.

    Science.gov (United States)

    Teimoori, Salma; Arimatsu, Yuji; Laha, Thewarach; Kaewkes, Sasithorn; Sereerak, Piya; Sripa, Manop; Tangkawattana, Sirikachorn; Brindley, Paul J; Sripa, Banchob

    2017-08-01

    Diagnosis of Opisthorchis viverrini infection by conventional stool examination is increasingly difficult due to the low intensity of the infection after several rounds of control programmes in endemic regions as well as coinfections with intestinal flukes. Therefore sensitive and specific diagnostic test is needed. In this study, a coproantigen sandwich ELISA using recombinant O. viverrini cathepsin F (rOv-CF) was developed. This sandwich ELISA employing chicken IgY raised against rOv-CF in combination with rabbit IgG antibody to the somatic O. viverrini antigens showed a lower detection limit (LLD) of 70ng native O. viverrini somatic antigens by spiking the parasite antigens into control feces. When applied to the diagnosis, the IgY-based sandwich ELISA exhibited sensitivity and specificity of 93.3% and 76.7%, respectively, in an investigation of 90 human cases positive or negative for opisthorchiasis. The positive predictive value (PPV) and negative predictive value (NPV) for this coproantigen detection were 66.7% and 95.2%, respectively. This IgY-based sandwich ELISA using parasite cathepsin F detection shows a promising immunodiagnostic alternative for human opisthorchiasis in endemic regions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Comparative Study of Three Different ELISA to Measure the Antibodies Against Infectious Bronchitis Virus in Vaccinated and Unvaccinated Broilers Estudo Comparativo de Três Diferentes Modalidades de Elisa para Medir os Anticorpos Contra o Vírus da Bronquite Infecciosa em Frangos Vacinados e Não Vacinados

    OpenAIRE

    Cardoso TC; C. Oliveira; SEL Da-Silva; HL Ferreira; Pinto AA

    2001-01-01

    Broilers were spray-vaccinated (n=150) with H120 serotype at one-day-old, challenged after 28 days with M41 IBV serotype and after bled at day 28, 34 and 46 after challenged. The respective sera were tested by the indirect ELISA (I-ELISA), sandwich ELISA (S-ELISA), liquid phase blocking ELISA (LPB-ELISA) and the standard serum neutralization test (SNT). For this purpose, a total of 300 sera samples, 150 from non vaccinated and 150 from vaccinated broilers were titrated by all the serological ...

  15. Experimental and theoretical studies of the structural and electronic properties of vanadium-benzene sandwich clusters and their anions: V(n)Bz(n)(0/-) (n = 1-5) and V(n)Bz(n-1)(0/-) (n = 2-5).

    Science.gov (United States)

    Masubuchi, Tsugunosuke; Iwasa, Takeshi; Nakajima, Atsushi

    2014-12-07

    One end open V(n)Bz(n)(-) (n = 1-5; Bz = benzene) and both ends open V(n)Bz(n-1)(-) (n = 2-5) vanadium-benzene cluster anions were studied using anion photoelectron spectroscopy and density functional calculations. The smaller (n ≤ 3) V(n)Bz(n) and V(n)Bz(n-1) clusters and corresponding anions were found to have structural isomers, whereas full-sandwiched V(n)Bz(n+1) clusters preferred to form multiple-decker sandwich structures. Several isomeric V2Bz2 structures were identified theoretically and the anion photoelectron spectra of V2Bz2(0/-) were explained well by the coexistence of two isomeric structures: (1) a V2-core structure sandwiched between benzene molecules and (2) an alternating sandwich structure with the spin state strongly dependent on the structure. The adiabatic electron affinity of both V(n)Bz(n) and V(n)Bz(n-1) was found to increase with the cluster size at larger sizes (n = 4 or 5) and approaches to that of V(n)Bz(n+1). The evolution of the structural and electronic properties of V(n)Bz(m) and V(n)Bz(m)(-) (m = n and n - 1) with size is discussed in comparison with V(n)Bz(n+1) and V(n)Bz(n+1)(-).

  16. Procollagen type I N-terminal propeptide (PINP) as an indicator of type I collagen metabolism: ELISA development, reference interval, and hypovitaminosis D induced hyperparathyroidism

    DEFF Research Database (Denmark)

    Orum, O; Hansen, M; Jensen, Charlotte Harken;

    1996-01-01

    A sandwich enzyme-linked immunosorbent assay (ELISA) for quantification of the N-terminal propeptide of human procollagen type I (PINP) utilizing purified alpha 1-chain specific rabbit antibodies is described. The ELISA measured the content of the alpha 1-chain of PINP independent of the molecula...

  17. Measuring Hordein (Gluten) in Beer – A Comparison of ELISA and Mass Spectrometry

    Science.gov (United States)

    Blundell, Malcolm J.; Goswami, Hareshwar P.; Howitt, Crispin A.

    2013-01-01

    Background Subjects suffering from coeliac disease, gluten allergy/intolerance must adopt a lifelong avoidance of gluten. Beer contains trace levels of hordeins (gluten) which are too high to be safely consumed by most coeliacs. Accurate measurement of trace hordeins by ELISA is problematic. Methods We have compared hordein levels in sixty beers, by sandwich ELISA, with the level determined using multiple reaction monitoring mass spectrometry (MRM-MS). Results Hordein levels measured by ELISA varied by four orders of magnitude, from zero (for known gluten-free beers) to 47,000 µg/mL (ppm; for a wheat-based beer). Half the commercial gluten-free beers were free of hordein by MS and ELISA. Two gluten-free and two low-gluten beers had zero ELISA readings, but contained significant hordein levels (pgluten in beverages such as beer and highlights the need for the development of new sensitive and selective quantitative assay such as MS. PMID:23509606

  18. The asymmetric sandwich theorem

    CERN Document Server

    Simons, Stephen

    2011-01-01

    We discuss the asymmetric sandwich theorem, a generalization of the Hahn-Banach theorem. As applications, we derive various results on the existence of linear functionals that include bivariate, trivariate and quadrivariate generalizations of the Fenchel duality theorem. Most of the results are about affine functions defined on convex subsets of vector spaces, rather than linear functions defined on vector spaces. We consider both results that use a simple boundedness hypothesis (as in Rockafellar's version of the Fenchel duality theorem) and also results that use Baire's theorem (as in the Robinson-Attouch-Brezis version of the Fenchel duality theorem). This paper also contains some new results about metrizable topological vector spaces that are not necessarily locally convex.

  19. Fracture of sandwiched composites

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Weh-Huei.

    1989-01-01

    Fracture of a pair of collinear cracks in various materials, such as an isotropic strip, an orthotropic strip, a bonded isotropic adhesive layer, and sandwiched orthotropic layers, is investigated. The crack surfaces are subjected to an arbitrary opening pressure p(x). The problems are formulated in terms of Fredholm integral equation of the second kind by making use the techniques of Fourier transform and finite Hilbert transform. In case of uniform opening pressure p(x)={sigma}, exact expressions for the stress intensity factors and the shape of deformed crack are obtained. Numerical calculations are carried out to study the effects of various boundary geometries and material properties on the fracture of the chosen materials.

  20. Theoretical study of the structure, bonding and electronic behaviour of sandwich complexes [M3(C7H7)2X3]- (M = Ni, Pd, Pt; X = F, Cl)

    Science.gov (United States)

    Zhou, Ke; Min, Suotian; Xue, Ganglin; Huang, Wendeng

    2014-08-01

    The correlations between the structural and electronic properties of the clusters [M3X3]3- and sandwich complexes [M3(C7H7)2X3]- (where M = Ni, Pd, Pt; X = F, Cl) were studied with density functional theory (B3PW91). All of the sandwich complexes are donating and back-donating metal-ligand bonding structures. The influence of the ligand, significant variations in the Msbnd C, Msbnd X, Msbnd M, Csbnd C bond lengths and binding energies were examined to obtain qualitative and quantitative pictures of the intramolecular C7R7+-M3X33- interactions. Our theoretical investigations show that the binding energies of the sandwich complexes gradually reduce from Ni to Pt, as well as from F to Cl. Meanwhile, the geometric and electronic structures and the relative stabilities have a strong relation to each other. S1). 7-B-(H-10) is a delocalised σ orbital, which has contributions from Pt (15% s orbital of each Pt, 8% d orbital of each Pt), and there is little contribution from Cl (Table S2). 7-C-(H-11) is a delocalised π orbital, which mainly involves contribution from Pt (25% dxz and dyz of each Pt) and Cl (8.5% pz of each Cl) (Table S3). 7-D-(H-14) is a delocalised σ orbital, which is mostly composed of d orbitals (14% for each Pt) and p orbitals (16% for each Cl) (Table S4). Pt s (10%) and d (10%) orbitals mainly participate in the formations of 7-E-(H-23), and there is a 13% p orbital contribution from each Cl (Table S5). For structure 13, the LUMO is mainly s orbitals of C, and there is some contribution from the s and d orbitals of Pt (Table S6), whereas the HOMO is mainly s orbitals of C (Table S7). 13-c-(H-14) is mainly the dxz and dyz orbitals of Pt (Table S8).NICS can be used to predict and understand some of the properties of a molecule, especially its stability due to aromatic stabilisation, which is based on the negative of the magnetic shielding computed at or above the geometrical centres of rings or clusters. Systems with negative NICS values are aromatic

  1. Robust and Air-Stable Sandwiched Organo-Lead Halide Perovskites for Photodetector Applications

    KAUST Repository

    Mohammed, Omar F.

    2016-02-25

    We report the simplest possible method to date for fabricating robust, air-stable, sandwiched perovskite photodetectors. Our proposed sandwiched structure is devoid of electron or hole transporting layers and also the expensive electrodes. These simpler architectures may have application in the perovskite-only class of solar cells scaling up towards commercialization.

  2. Sandwich complex-containing macromolecules: property tunability through versatile synthesis.

    Science.gov (United States)

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola

    2014-03-01

    Sandwich complexes feature unique properties as the physical and electronic properties of a hydrocarbon ligand or its derivative are integrated into the physical, electronic, magnetic, and optical properties of a metal. Incorporation of these complexes into macromolecules results in intriguing physical, electrical, and optical properties that were hitherto unknown in organic-based macromolecules. These properties are tunable through well-designed synthetic strategies. This review surveys many of the synthetic approaches that have resulted in tuning the properties of sandwich complex-containing macromolecules. While the past two decades have seen an ever-growing number of research publications in this field, gaps remain to be filled. Thus, we expect this review to stimulate research interest towards bridging these gaps, which include the insolubility of some of these macromolecules as well as expanding the scope of the sandwich complexes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Development of Aircraft Sandwich Parts

    Directory of Open Access Journals (Sweden)

    J. Křena

    2000-01-01

    Full Text Available The presented paper shows the design and development process of sandwich parts. A spoiler plate and a main landing gear door are developed. Sandwich parts are made of C/E composite facings and a foam core. FE models have been used for optimization of structures. Emphasis has been placed on deformations of parts under a few load cases. Experimental tests have been used for a verification of structure parts loaded by concentrated forces.

  4. Rapid screen for truncating ATM mutations by PTT-ELISA

    Energy Technology Data Exchange (ETDEWEB)

    Du Liutao; Lai, C.-H. [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, CA 90095 (United States); Concannon, Patrick [Department of Biochemistry and Molecular Genetics, University of Virginia, VA 22908 (United States); Gatti, Richard A. [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, CA 90095 (United States); Department of Human Genetics, David Geffen School of Medicine at UCLA, CA 90095 (United States)], E-mail: rgatti@mednet.ucla.edu

    2008-04-02

    Mutations in the ataxia-telangiectasia mutated (ATM) gene are responsible for the autosomal recessive genetic disorder, ataxia-telangiectasia (A-T). Approximately 80% of ATM mutations found in A-T patients results in truncations, which can be detected by Protein Truncation Test (PTT). Conventional PTT uses SDS-PAGE electrophoresis to detect mobility of radiolabeled truncated protein fragments. In this study, we developed a non-radioactive Protein Truncation Test which utilizes an enzyme-linked immunosorbent assay (PTT-ELISA) to detect ATM mutations in eight overlapping fragments. N- and C-terminal epitopes (c-myc and V5, respectively) were introduced into transcription/translation products, which could then be detected by Sandwich ELISA. Using this assay, we screened 9 newly diagnosed A-T patients consecutively. Of the 18 expected mutations, 14 truncating mutations were independently identified by cDNA direct sequencing and/or DNA dHPLC analysis. PTT-ELISA detected all of these 14. Four mutations were novel. The PTT-ELISA provides a rapid method for detecting truncating mutations in large genes and should be considered prior to using more laborious or costly methods, such as direct sequencing.

  5. Detection of hazelnuts and almonds using commercial ELISA test kits.

    Science.gov (United States)

    Garber, Eric A E; Perry, Jesse

    2010-03-01

    Three commercial sandwich enzyme-linked immunosorbent assay (ELISA) test kits for the detection of hazelnuts and almonds were evaluated. Limits of detection and dynamic ranges were determined for hazelnuts and almonds spiked into cooked oatmeal, dipping chocolate, and muffins (baked). The limit of detection values varied from 1 to 38 μg/g, depending on the food matrix and ELISA test kit. Percent recoveries based on the standards supplied with the test kits varied from 10% to 170%. It is impossible to ascertain whether the percent recoveries reflect the performance of the ELISAs or differences between the protein content of the nuts used to spike the samples and the test kit standards. Unfortunately, reference materials do not exist that can be used to compare the results from different test kits and standardize the test kit standards. Also, insufficient knowledge regarding the epitope specificity of the antibodies used in the ELISAs further hinders interpretation of the results generated by the different test kits.

  6. Magnetism and electronic structure of (001)- and (111)-oriented LaTiO{sub 3} bilayers sandwiched in LaScO{sub 3} barriers

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Yakui; Dong, Shuai, E-mail: sdong@seu.edu.cn [Department of Physics and Jiangsu Key Laboratory of Advanced Metallic Materials, Southeast University, Nanjing 211189 (China)

    2015-05-07

    In this study, the magnetism and electronic structure of LaTiO{sub 3} bilayers along both the (001) and (111) orientations are calculated using the density functional theory. The band insulator LaScO{sub 3} is chosen as the barrier layer and substrate to obtain the isolating LaTiO{sub 3} bilayer. For both the (001)- and (111)-oriented cases, LaTiO{sub 3} demonstrates the G-type antiferromagnetism as the ground state, similar to the bulk material. However, the electronic structure is significantly changed. The occupied bands of Ti are much narrower in the (111) case, giving a nearly flat band. As a result, the exchange coupling between nearest-neighbor Ti ions is reformed in these superlattices, which will affect the Néel temperature significantly.

  7. Elisa Biagini (Florencia, 1970

    Directory of Open Access Journals (Sweden)

    Berta González Saavedra

    2017-01-01

    Full Text Available Elisa Biagini vive en Italia tras haber estudiado y enseñado en los Estados Unidos durante varios años. Sus poesías han sido publicadas en varias revistas y antologías italianas y americanas, entre otras. Algunas de las más recientes son Nuovissima poesia italiana (Mondadori, 2004 y Parola plurale (Sosselam 2005. Ha publicado siete colecciones poéticas, algunas bilingües, entre las que figuran  L'Ospite (Einaudi, 2004, Fiato. Parole per musica (Edizionidif, 2006, Nel bosco (Einaudi, 2007, The guest in the wood (Chelsea editions, 2013 – 2014 Best Translated Book Award, y la reciente Da una crepa (Einaudi, 2014. Sus poesías han sido traducidas al inglés, español, francés, portugués, japonés, croata, eslovaco, alemán, albanés, ruso, árabe y chino. Ha participado en importantes festivales italianos e internacionales (entre otros, en Italia “Festival della Letteratura” de Mantua, “Festival Poesia” de Parma, “RomaPoesia” de Roma, y en el extranjero “Stanza- Scotland's International Poetry Festival” en St. Andrews, Escocia, “Dubai International Poetry Festival” en Emiratos Árabes Unidos, “PoesieFestivalBerlin” en Berlín, “International Writers Workshop” en Hong Kong, “Struga Poetry Festival” en Struga, Macedonia, “Poetry Parnassus” en Londres, “Printemps des poètes” en Luxemburgo, “Queensland Poetry Festival” en Brisbane, Australia, “Festival Internacional de Poesía de Granada” en Nicaragua, “Xu Zhimo Poetry and Art Festival” en el King's College de Cambridge. Asimismo es traductora de poesía americana y, además de editar algunas colecciones de poetisas americanas contemporáneas, se ha encargado de la edición del volumen Nuovi poeti americani (Einaudi, 2006. Infine, insegna Scrittura Creativa (poesia, Travel Writing e Storia dell'Arte in Italia e all’estero, además de colaborar con artistas visules, coreógrafos y músicos. Entre otras actividades, es artista visual. www.elisabiagini.it

  8. Immunometric Antibody Sandwich Enzyme-Linked Immunosorbent Assay.

    Science.gov (United States)

    Kohl, Thomas O; Ascoli, Carl A

    2017-06-01

    The antibody sandwich enzyme-linked immunosorbent assay (ELISA) is the most commonly used assay for rapid and accurate detection of antigens. It displays greater sensitivity compared with the indirect ELISA and can be used to determine absolute antigen concentrations in unknown samples provided purified antigen standards are available, although it requires the use of two different antibodies. Briefly, wells are coated with antigen-specific capture antibody then incubated with samples containing unknown antigen. Washing removes unbound antigen and exogenous sample protein before incubation with a second antigen-specific detection antibody, washing, and reincubation with a reporter-labeled tertiary antibody. After tertiary antibody is washed off, substrate is added and hydrolysis is measured spectrophotometrically. The signal intensity is directly proportional to the concentration of the antigen in the test sample. © 2017 Cold Spring Harbor Laboratory Press.

  9. Development and application of a double-antigen sandwich enzyme-linked immunosorbent assay for detection of antibodies to porcine circovirus 2.

    Science.gov (United States)

    Ge, Meng; Luo, Wei; Jiang, Daliang; Li, Runcheng; Zhao, Wenwei; Chen, Guoliang; Yang, Xingdong; Yu, Xinglong

    2012-09-01

    A double-antigen sandwich enzyme-linked immunosorbent assay (ELISA) is described for detection of porcine circovirus 2 (PCV2) antibodies using the well-characterized recombinant PCV2 capsid protein. In a comparative test of 394 pig sera against an indirect immunofluorescence (IIF) test and a commercial ELISA kit (also based on the recombinant PCV2 capsid protein), the results showed that the diagnostic sensitivity, specificity, and accuracy of the assay were, respectively, 90.61, 94.02, and 91.62% compared with IIF and 94.38, 95.28, and 94.67% compared with the commercial ELISA kit. Assay of 12 PCV-free pigs over a 5-week period produced only PCV2-negative titers by all 3 methods. These results and the seroprofiles of 4 pig farms obtained by both the commercial ELISA kit and the double-antigen sandwich ELISA indicate that the sandwich ELISA is a reliable method for detection of antibodies to PCV2. Additionally, the method described here permits the use of undiluted test serum samples simultaneously loaded with horseradish peroxidase (HRP)-conjugated antigen into the test well, and the complete test procedure can be performed in less than 90 min. This double-antigen sandwich ELISA should be a useful tool to aid swine industry professionals in deciding the intervention strategies for the control of PCV2-associated diseases.

  10. Comparative Diagnosis of Serum IgG1 and Coproantigen ELISA for Fasciolosis Detection of Goats in Mexico

    Science.gov (United States)

    Molina-Mendoza, Pedro; Hernández-Guzmán, Karina; Olivares-Pérez, Jaime; Sarracent-Pérez, Jorge; Zumaquero-Ríos, José

    2016-01-01

    The objective of present study was to determine the prevalence of natural caprine fasciolosis in the Mixteca region of Mexico using coproantigen and serum IgG1 ELISA tests for comparative purposes. A total of 1070 serum and faecal samples were analyzed for IgG1 antibodies and coproantigens, using ELISA with E/S products as antigen and a monoclonal antibody-based sandwich ELISA. Prevalence of 73.46% was found using the serological ELISA and a percentage of 77.20 was found for coproantigen ELISA. The diagnostic sensitivity and specificity for serum ELISA were 86.7% and 96.4%, and for the coproantigen ELISA they were 93.1% and 97.8%, respectively. The seropositive samples were further categorized as low, medium, or high positivity. Results show a great proportion of low and medium positive goats when the serum ELISA test was used. Correlation coefficients between coproantigens and seropositivity were statistically significant (P < 0.01) for low seropositivity (r = 0.93) and medium seropositivity (r = 0.84). The accuracy of faecal antigen ELISA was higher compared to indirect ELISA serological test. Two ELISAs were shown to be useful for demonstrating the current status of F. hepatica infection in the endemic areas and can be employed in studies on epidemiology as well as anthelmintics treatment for preventing economic loss and the risk of transmission to humans. PMID:27563665

  11. Comparative Diagnosis of Serum IgG1 and Coproantigen ELISA for Fasciolosis Detection of Goats in Mexico.

    Science.gov (United States)

    Villa-Mancera, Abel; Molina-Mendoza, Pedro; Hernández-Guzmán, Karina; Olivares-Pérez, Jaime; Sarracent-Pérez, Jorge; Zumaquero-Ríos, José

    2016-01-01

    The objective of present study was to determine the prevalence of natural caprine fasciolosis in the Mixteca region of Mexico using coproantigen and serum IgG1 ELISA tests for comparative purposes. A total of 1070 serum and faecal samples were analyzed for IgG1 antibodies and coproantigens, using ELISA with E/S products as antigen and a monoclonal antibody-based sandwich ELISA. Prevalence of 73.46% was found using the serological ELISA and a percentage of 77.20 was found for coproantigen ELISA. The diagnostic sensitivity and specificity for serum ELISA were 86.7% and 96.4%, and for the coproantigen ELISA they were 93.1% and 97.8%, respectively. The seropositive samples were further categorized as low, medium, or high positivity. Results show a great proportion of low and medium positive goats when the serum ELISA test was used. Correlation coefficients between coproantigens and seropositivity were statistically significant (P < 0.01) for low seropositivity (r = 0.93) and medium seropositivity (r = 0.84). The accuracy of faecal antigen ELISA was higher compared to indirect ELISA serological test. Two ELISAs were shown to be useful for demonstrating the current status of F. hepatica infection in the endemic areas and can be employed in studies on epidemiology as well as anthelmintics treatment for preventing economic loss and the risk of transmission to humans.

  12. Comparative Diagnosis of Serum IgG1 and Coproantigen ELISA for Fasciolosis Detection of Goats in Mexico

    Directory of Open Access Journals (Sweden)

    Abel Villa-Mancera

    2016-01-01

    Full Text Available The objective of present study was to determine the prevalence of natural caprine fasciolosis in the Mixteca region of Mexico using coproantigen and serum IgG1 ELISA tests for comparative purposes. A total of 1070 serum and faecal samples were analyzed for IgG1 antibodies and coproantigens, using ELISA with E/S products as antigen and a monoclonal antibody-based sandwich ELISA. Prevalence of 73.46% was found using the serological ELISA and a percentage of 77.20 was found for coproantigen ELISA. The diagnostic sensitivity and specificity for serum ELISA were 86.7% and 96.4%, and for the coproantigen ELISA they were 93.1% and 97.8%, respectively. The seropositive samples were further categorized as low, medium, or high positivity. Results show a great proportion of low and medium positive goats when the serum ELISA test was used. Correlation coefficients between coproantigens and seropositivity were statistically significant (P<0.01 for low seropositivity (r=0.93 and medium seropositivity (r=0.84. The accuracy of faecal antigen ELISA was higher compared to indirect ELISA serological test. Two ELISAs were shown to be useful for demonstrating the current status of F. hepatica infection in the endemic areas and can be employed in studies on epidemiology as well as anthelmintics treatment for preventing economic loss and the risk of transmission to humans.

  13. A comparative microleakage evaluation of three different base materials in Class I cavity in deciduous molars in sandwich technique using dye penetration and dentin surface interface by scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Babita Niranjan

    2016-01-01

    Full Text Available Introduction: A major objective in restorative dentistry is the control of marginal leakage, which may occur because of dimensional changes or lack of adaptation of restorative material to the cavity preparation. Numerous techniques have been advocated to overcome polymerization shrinkage in composite restorations. Aim and Objectives: This study investigated microleakage of three different bases under composite resin in sandwich technique using dye penetration and dentin surface interface using scanning electron microscope (SEM. Materials and Methods: Sixty extracted deciduous molars were stored in distilled water and Class I cavities with a width of about one-fourth of intercuspal distance and a depth of 0.5-1 mm below the dentino-enamel junction was prepared without bevels. In Group 1 - glass ionomer cement (GIC; Group 2 - mineral trioxide aggregate (MTA; Group 3 - Biodentine™ was placed as a base under composite. Teeth were longitudinally sectioned in two halves, through the centers of the restoration, immersed in 2% methylene blue and microleakage was evaluated under stereomicroscope and surface interface between base and dentin was evaluated under SEM. Results:Under the condition of in vitro study, less microleakage and less internal gaps were seen in Biodentine™ (0.00 ± 0.00 and 4.00 ± 1.59 group than MTA (0.00 ± 0.00 and 6.08 ± 1.82 and GIC (25.25 ± 6.57 and 14.73 ± 3.72, respectively and showed very strong positive correlation between microleakage and internal gaps. Conclusion: Biodentine™ exhibits superior marginal sealing ability as well as marginal adaptation under composite resin as compared to MTA and GIC.

  14. Experimental and theoretical studies of the structural and electronic properties of vanadium–benzene sandwich clusters and their anions: V{sub n}Bz{sub n}{sup 0/−} (n = 1–5) and V{sub n}Bz{sub n−1}{sup 0/−} (n = 2–5)

    Energy Technology Data Exchange (ETDEWEB)

    Masubuchi, Tsugunosuke [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Iwasa, Takeshi [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); JST, ERATO, Nakajima Designer Nanocluster Assembly Project, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012 (Japan); Nakajima, Atsushi, E-mail: nakajima@chem.keio.ac.jp [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); JST, ERATO, Nakajima Designer Nanocluster Assembly Project, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012 (Japan); Keio Institute of Pure and Applied Sciences (KiPAS), Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2014-12-07

    One end open V{sub n}Bz{sub n}{sup −} (n = 1–5; Bz = benzene) and both ends open V{sub n}Bz{sub n−1}{sup −} (n = 2–5) vanadium–benzene cluster anions were studied using anion photoelectron spectroscopy and density functional calculations. The smaller (n ≤ 3) V{sub n}Bz{sub n} and V{sub n}Bz{sub n−1} clusters and corresponding anions were found to have structural isomers, whereas full-sandwiched V{sub n}Bz{sub n+1} clusters preferred to form multiple-decker sandwich structures. Several isomeric V{sub 2}Bz{sub 2} structures were identified theoretically and the anion photoelectron spectra of V{sub 2}Bz{sub 2}{sup 0/−} were explained well by the coexistence of two isomeric structures: (1) a V{sub 2}-core structure sandwiched between benzene molecules and (2) an alternating sandwich structure with the spin state strongly dependent on the structure. The adiabatic electron affinity of both V{sub n}Bz{sub n} and V{sub n}Bz{sub n−1} was found to increase with the cluster size at larger sizes (n = 4 or 5) and approaches to that of V{sub n}Bz{sub n+1}. The evolution of the structural and electronic properties of V{sub n}Bz{sub m} and V{sub n}Bz{sub m}{sup −} (m = n and n − 1) with size is discussed in comparison with V{sub n}Bz{sub n+1} and V{sub n}Bz{sub n+1}{sup −}.

  15. Immunometric Double-Antibody Sandwich Enzyme-Linked Immunosorbent Assay.

    Science.gov (United States)

    Kohl, Thomas O; Ascoli, Carl A

    2017-06-01

    The double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) is preferentially used to determine the concentration of unknown antibody in a sample. Pure antigen is not required in this assay; however, the use of a reporter-labeled detection antibody is essential. The double-antibody sandwich ELISA is suitable for epitope mapping of different monoclonal antibodies that have been generated against a single antigen. First, plates are coated with a capture antibody specific for immunoglobulins generated by immunization of a host species. Next, the test antibody solution (e.g., serum) is incubated with the capture antibody to facilitate binding. The plates are washed to remove unbound antibody, and then antigen is added. The plates are washed again followed by the addition of an antigen-specific reporter-labeled antibody. Following incubation, unbound reporter antibody is washed off, and reporter-specific substrate is added. Reporter-mediated substrate hydrolysis is visualized and measured. The signal is proportional to the number of test antibodies present in the serum. © 2017 Cold Spring Harbor Laboratory Press.

  16. Structural and failure mechanics of sandwich composites

    CERN Document Server

    Carlsson, LA; Carlsson, Leif A

    2011-01-01

    Focusing on important deformation and failure modes of sandwich structures, this volume describes the mechanics behind fracture processes. The text also reviews test methods developed for the cr, structural integrity, and failure mechanisms of sandwich structures.

  17. Measuring hordein (gluten in beer--a comparison of ELISA and mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Gregory J Tanner

    Full Text Available BACKGROUND: Subjects suffering from coeliac disease, gluten allergy/intolerance must adopt a lifelong avoidance of gluten. Beer contains trace levels of hordeins (gluten which are too high to be safely consumed by most coeliacs. Accurate measurement of trace hordeins by ELISA is problematic. METHODS: We have compared hordein levels in sixty beers, by sandwich ELISA, with the level determined using multiple reaction monitoring mass spectrometry (MRM-MS. RESULTS: Hordein levels measured by ELISA varied by four orders of magnitude, from zero (for known gluten-free beers to 47,000 µg/mL (ppm; for a wheat-based beer. Half the commercial gluten-free beers were free of hordein by MS and ELISA. Two gluten-free and two low-gluten beers had zero ELISA readings, but contained significant hordein levels (p<0.05, or near average (60-140% hordein levels, by MS, respectively. Six beers gave false negatives, with zero ELISA readings but near average hordein content by MS. Approximately 20% of commercial beers had ELISA readings less than 1 ppm, but a near average hordein content by MS. Several barley beers also contained undeclared wheat proteins. CONCLUSIONS: ELISA results did not correlate with the relative content of hordein peptides determined by MS, with all barley based beers containing hordein. We suggest that mass spectrometry is more reliable than ELISA, as ELISA enumerates only the concentration of particular amino-acid epitopes; this may vary between different hordeins and may not be related to the absolute hordein concentration. MS quantification is undertaken using peptides that are specific and unique, enabling the quantification of individual hordein isoforms. This outlines the problem of relying solely on ELISA determination of gluten in beverages such as beer and highlights the need for the development of new sensitive and selective quantitative assay such as MS.

  18. Technology sandwich panels with mineral wool insulation

    OpenAIRE

    Tyulenev M.; Burtzeva M.; Mednikova E.

    2016-01-01

    Sandwich panel — self–supporting structure consisting of metal cladding and thermal insulation core. As a heat–insulating core used mineral wool, foamed plastics. Production of sandwich panels with insulation mineral wool performed on modular lines for the production of aggregate or conveyer scheme. Sandwich panels are used as load–bearing elements of the facades, as well as a roof covering.

  19. Influence of Si buffer layer on the giant magnetoresistance effect in Co/Cu/Co sandwiches

    Institute of Scientific and Technical Information of China (English)

    李冠雄; 沈鸿烈; 沈勤我; 李铁; 邹世昌

    2000-01-01

    The Co/Cu/Co sandwiches with a semiconductor Si buffer layer were prepared by high vacuum electron-beam evaporation. The influence of the Si buffer layer with different thickness on the giant magnetoresistance (GMR) effect in the Co/Cu/Co sandwiches was investigated. It was found that the GMR showed an obvious anisotropy when the thickness of Si buffer layer was larger than or equal to 0.9 nm, and that the GMR was basically isotropic with an Si buffer layer thinner than 0.9 nm. The anisotropic behavior of GMR can be ascribed to the in-plane magnetic anisotropy in the sandwiches. Due to the interdiffusion at the Si buffer/Co interface, a Co2Si interface layer with a good (301) texture formed and induced the in-plane magnetic anisotropy in the sandwiches. The dependence of the crystalline texture of the sandwiches on the thickness of Si buffer layer was also studied.

  20. Wire and Packing Tape Sandwiches

    Science.gov (United States)

    Rabinowitz, Sandy

    2009-01-01

    In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

  1. High temperature structural sandwich panels

    Science.gov (United States)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  2. Establishment of optimized ELISA system specific for HLA-G in body fluids.

    Science.gov (United States)

    Ouji-Sageshima, N; Geraghty, D E; Ishitani, A; Hatake, K; Ito, T

    2016-12-01

    Recently, human leukocyte antigen-G (HLA-G) has been a focus in the field of reproductive immunology, tumor progression and transplantation, because of its inhibitory function as ligand to the inhibitory receptors leukocyte immunoglobulin-like receptors (LILR) B1 and LILRB2. The HLA-G is expressed in distinct mRNA isoforms, one of which encodes a soluble HLA-G (sHLA-G) protein, detectable by sandwich ELISA. Therefore, sHLA-G ELISAs have been used as a noninvasive diagnosis system. While a number of sHLA-G-specific ELISAs have been described, our prior studies showed that data obtained by the conventional ELISA system detecting sHLA-G in body fluids was not consistent with the data obtained from immunoprecipitation (IP)/immunoblotting (IB). Therefore, we established an optimized ELISA system described in this report, which yields results consistent with IP/IB analysis. Using this system, we determined sHLA-G protein in amniotic fluids, and found that sHLA-G levels at preterm (∼36 weeks) were clearly higher than those at term (37-41 weeks). These data and supporting experiments showed that the ELISA system we established can be an useful tools for the detection of sHLA-G protein in body fluids than the conventional ELISA system.

  3. Prediction of Thermal and Elastic Properties of Honeycomb Sandwich Plate for Analysis of Thermal Deformation

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seok Min; Lee, Jang Il; Byun, Jae Ki; Choi, Young Don [Korea Univ., Seoul (Korea, Republic of)

    2014-04-15

    Thermal problems that are directly related to the lifetime of an electronic device are becoming increasingly important owing to the miniaturization of electronic devices. To solve thermal problems, it is essential to study thermal stability through thermal diffusion and insulation. A honeycomb sandwich plate has anisotropic thermal conductivity. To analyze the thermal deformation and temperature distribution of a system that employs a honeycomb sandwich plate, the thermal and elastic properties need to be determined. In this study, the thermal and elastic properties of a honeycomb sandwich plate, such as thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and shear modulus, are predicted. The properties of a honeycomb sandwich plate vary according to the hexagon size, thickness, and material properties.

  4. Enrichment-ELISA for Detection of Salmonella typhi From Food and Water Samples

    Institute of Scientific and Technical Information of China (English)

    S.KUMAR; K.BALAKRISHNA; HV.BATRA

    2008-01-01

    Objective Development of monoclonal antibody based sandwich enzyme linked immunosorbant assay(sELISA)for rapid detection of Salmonella enterica serovar typhi(S.typhi) from food and water samples and optimization of enrichment procedures for use with the developed sELISA to increase the detection Sensitivity of the assay. Methods Spleen cells from BALB/c mice immunized with flagellin(H=d)antigen of S.typhi were fused with Sp2/0 myeloma cells.The hybridoma cell line specific to H=d antigen was established.characterized and ascites raised against one of these clones.The hypefimmune serum to flagellin antigen was raised in New Zealand White rabbits.An sELISA was developed using polyclonalantibody as capture and monoelonal antibody as detection antibody.To design the efficient culture sUrategies for use with the sELISA.different pre-enrichment and enrichment brothswere evaluated.The mediaincluded buffered peptonewater(BPW)and brain heart infusion broth for pre-enrichment and selenite F broth and Rappaport-Vassiliadis broth as enrichment broths.The developed sELISA with preceding enrichment step in BPW(Enrichment-ELISA)was evaluated in various food samples artificially inoculated with S. typhi bacteria.Various food(30)and water(35)samples collected from field were also tested by Enrichment-ELISA and culture method. Results Out of four specific clones to H=d antigen,one clone(#2/56.IgG2a isotype)was usedin sELISA.The sELISA had the detectionlimit of 104-105 cfu of S.typhi.Of the various broths used with sELISA,BPW was found to yield maximum ELISA values.Enrichment-ELISA,when tested in artificially inoculated food samples,generally,could detect 102S.typhi cfu/mL within 10 h from variousfood rinses(meat,vegetable)and milk samples.After overnight enrichment in BPW,as less as 2 bacteria per 10 mL of milk,meat rinse.and chicken rinse could be detected.Only one of the field samples(water)gave false positive result by Enrichment-ELISA.Conclusion In comparison to culture

  5. Kinetic ELISA in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Debashis Dutta

    2011-06-01

    Full Text Available In this article, we describe the kinetic ELISA of Blue Tongue and Epizootic Hemorrhagic Disease viral antibodies in microfluidic channels by monitoring the rate of generation of the enzyme reaction product under static conditions. It has been shown that this format of the immunoassay allows very reliable quantitation of the target species using inexpensive glass microchips and a standard epifluorescence microscope system coupled to a CCD camera. For the viral antibodies assayed here, the limit of detection (LOD for the analyte concentration in our microchips was established to be 3–5 times lower than that obtained on commercial microwell plates using a fiftieth of the sample volume and less than a third of the incubation time. Our analyses further show that when compared to the end-point ELISA format, the kinetic mode of this assay yields an improvement in the LOD by over an order of magnitude in microfluidic devices. This benefit is primarily realized as the observed variation in the background fluorescence (signal at the start of the enzyme reaction period was significantly larger than that in the rate of signal generation upon repeating these assays in different microchannels/microchips. Because the kinetic ELISA results depend only on the latter quantity, the noise level in them was substantially lower compared to that in its end-point counterpart in which the absolute fluorescence measurements are of greater significance. While a similar benefit was also recorded through implementation of kinetic ELISAs on the microwell platform, the improvement in LOD registered in that system was not as significant as was observed in the case of microfluidic assays.

  6. Protein unfolding allows use of commercial antibodies in an apolipoprotein M sandwich ELISA

    DEFF Research Database (Denmark)

    Bosteen, Markus Høybye; Dahlbäck, Björn; Nielsen, Lars Bo;

    2015-01-01

    diseases such as multiple sclerosis and rheumatoid arthritis. The ability to accurately measure apoM is crucial for investigating its biological functions and possible clinical implications. However, reliable commercial methods have been lacking so far. Therefore, we have developed an assay...

  7. Cascaded-systems analysis of sandwich x-ray detectors

    Science.gov (United States)

    Kim, D. W.; Kim, J.; Yun, S.; Youn, H.; Kim, H. K.

    2016-12-01

    Active sandwich-like multilayer detectors have been developed, and their potential for motion-artifact-free dual-energy x-ray imaging at a single exposure has been demonstrated in the material decomposition context. Since the sandwich detector uses the x-ray beam transmittance through the front layer, direct x-ray interaction within photodiodes in the front layer is unavoidable, and which can increase noise in the front detector images. Similar direct x-ray interaction can also occur in the rear detector layer. To obtain a better contrast performance, an additional filter layer can be placed between the two detector layers. However, this filter layer can increase adversely noise in images obtained from the rear detector layer by reducing the number of x-ray photons reaching it. A theoretical model, which can describe the signal-to-noise performance of the sandwich detector as functions of various design parameters, has been developed by using a linear cascaded-systems theory. From the cascaded-systems analysis, the direct x-ray interaction increases noise at the high spatial frequencies where the number of secondary quanta lessens. The intermediate filter layer enhances the contribution of additive electronic noise in the overall noise performance of the rear detector layer. The detailed cascaded-systems analysis on the x-ray sandwich detectors are reported in comparisons with the measured noise-power spectra and detective quantum efficiencies. The developed model will be useful for a better design and practical use of a sandwich detector for single-shot dual-energy imaging.

  8. A Sandwich Electrochemical Immunosensor Using Magnetic DNA Nanoprobes for Carcinoembryonic Antigen

    Directory of Open Access Journals (Sweden)

    Ning Gan

    2011-10-01

    Full Text Available A novel magnetic nanoparticle-based electrochemical immunoassay of carcinoembryonic antigen (CEA was designed as a model using CEA antibody-functionalized magnetic beads [DNA/Fe3O4/ZrO2; Fe3O4 (core/ZrO2 (shell nano particles (ZMPs] as immunosensing probes. To design the immunoassay, the CEA antibody and O-phenylenediamine (OPD were initially immobilized on a chitosan/nano gold composite membrane on a glassy carbon electrode (GCE/CS-nano Au, which was used for CEA recognition. Then, horseradish peroxidase (HRP-labeled anti-CEA antibodies (HRP-CEA Ab2 were bound to the surface of the synthesized magnetic ZMP nanoparticles as signal tag. Thus, the sandwich-type immune complex could be formed between secondary antibody (Ab2 modified DNA/ZMPs nanochains tagged by HRP and GCE/CS-nano Au. Unlike conventional nanoparticle-based electrochemical immunoassays, the recognition elements of this immunoassay included both electron mediators and enzyme labels, which obviously simplifies the electrochemical measurement process. The sandwich-type immunoassay format was used for online formation of the immunocomplex of CEA captured in the detection cell with an external magnet. The electrochemical signals derived from HRP during the reduction of H2O2 with OPD as electron mediator were measured. The method displayed a high sensitivity for CEA detection in the range of 0.008–200 ng/mL, with a detection limit of 5 pg/mL (estimated at a signal-to-noise ratio of 3. The precision, reproducibility, and stability of the immunoassay were good. The use of the assay was evaluated with clinical serum samples, and the results were in excellent accordance with those obtained using the standard enzyme-linked immunosorbent assay (ELISA method. Thus, the magnetic nanoparticle-based assay format is a promising approach for clinical applications, and it could be further developed for the detection of other biomarkers in cancer diagnosis.

  9. Canine specific ELISA for coagulation factor VII

    DEFF Research Database (Denmark)

    Knudsen, Tom; Kjelgaard-Hansen, Mads; Tranholm, Mikael;

    2011-01-01

    available to date. In this study, a canine specific ELISA for measurement of FVII:Ag in plasma was developed and validated. The FVII:Ag ELISA correctly diagnosed homozygous and heterozygous hereditary FVII deficiency. Together with activity based assays, such as FVII:C, the FVII:Ag ELISA should be valuable...

  10. Composite Sandwich Technologies Lighten Components

    Science.gov (United States)

    2010-01-01

    Leveraging its private resources with several Small Business Innovation Research (SBIR) contracts with both NASA and the U.S. Department of Defense, WebCore Technologies LLC, of Miamisburg, Ohio, developed a fiber-reinforced foam sandwich panel it calls TYCOR that can be used for a wide variety of industrial and consumer applications. Testing at Glenn Research Center?s Ballistic Impact Facility demonstrated that the technology was able to exhibit excellent damage localization and stiffness during impact. The patented and trademarked material has found use in many demanding applications, including marine, ground transportation, mobile shelters, bridges, and most notably, wind turbines.

  11. Magnetic and Structural Properties in Co/Cu/Co Sandwiches with Ni and Cr Buffer Layers

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The magnetic and structural properties in Co/Cu/Co sandwiches with Ni and Cr buffer layers were investigated. It was found that the coercivity in Ni layer buffered samples decreases with increasing Ni layer thickness, while that in Cr layer buffered ones increases with increasing Cr layer thickness, leading to a large difference in field sensitivity of their giant magnetoresistance (GMR) properties. X-ray diffraction and high resolution transmission electron microscope images exhibited that there is a strong fcc (111) texture in the samples with Ni buffer layer. But there are only randomly oriented polycrystalline grains in Cr buffered sandwiches. According to atomic force microscope topography, the surface roughness of Cr buffered sandwiches is smaller than that of Ni buffered ones. It is demonstrated that buffer layer influences both magnetic and structural properties in Co/Cu/Co sandwiches as well as their GMR characteristics.

  12. Standard Terminology of Structural Sandwich Constructions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This terminology covers terms necessary for a basic uniform understanding and usage of the language peculiar to structural sandwich constructions. The simplest structural sandwich is a three layered construction formed by bonding a thin layer (facing) to each side of a thick layer (core).

  13. Development and Evaluation of Stitched Sandwich Panels

    Science.gov (United States)

    Stanley, Larry E.; Adams, Daniel O.; Reeder, James R. (Technical Monitor)

    2001-01-01

    This study explored the feasibility and potential benefits provided by the addition of through-the-thickness reinforcement to sandwich structures. Through-the-thickness stitching is proposed to increase the interlaminar strength and damage tolerance of composite sandwich structures. A low-cost, out-of-autoclave processing method was developed to produce composite sandwich panels with carbon fiber face sheets, a closed-cell foam core, and through-the-thickness Kevlar stitching. The sandwich panels were stitched in a dry preform state, vacuum bagged, and infiltrated using Vacuum Assisted Resin Transfer Molding (VARTM) processing. For comparison purposes, unstitched sandwich panels were produced using the same materials and manufacturing methodology. Test panels were produced initially at the University of Utah and later at NASA Langley Research Center. Four types of mechanical tests were performed: flexural testing, flatwise tensile testing, core shear testing, and edgewise compression testing. Drop-weight impact testing followed by specimen sectioning was performed to characterize the damage resistance of stitched sandwich panels. Compression after impact (CAI) testing was performed to evaluate the damage tolerance of the sandwich panels. Results show significant increases in the flexural stiffness and strength, out-of-plane tensile strength, core shear strength, edgewise compression strength, and compression-after-impact strength of stitched sandwich structures.

  14. Natural fabric sandwich laminate composites: development and investigation

    Indian Academy of Sciences (India)

    C K ARVINDA PANDIAN; H SIDDHI JAILANI; A RAJADURAI

    2017-02-01

    In this work, eco-friendly natural fabric sandwich laminate (NFSL) composites are formulated using jute and linen-fabric-reinforced epoxy with different layer ratios (5:0, 4:1, 3:2, 2:3, 1:4 and 0:5) by hand layup system. Different mechanical attributes (tensile, flexural and impact) of the NFSL composites are quantified. Thermal stability and water absorption behaviour of the NFSL composites are also assessed. A scanning electron microscope (SEM) and optical microscope are used for qualitative analysis of NFSL composites’ interfacial properties. Two layers of jute and three layers of linen sandwich laminate have registered peak values in tensile and impact properties. The five layers of linen laminate composite have exhibited high flexural strength, been proven to have good thermal stability and furthermore shown better water absorption behaviour than any other laminate composites.

  15. Current rectification in nickelocenylferrocene sandwiched between two gold electrodes.

    Science.gov (United States)

    Matsuura, Yukihito

    2013-01-07

    I present a theoretical study of the electronic transport properties of nickelocenylferrocene sandwiched between gold electrodes. Compared with the biferrocene system, the nickelocenylferrocene system had high electrical conduction and rectification in the bias range -1 to 1 V. Furthermore, the spin-down states of the nickelocenylferrocene system exhibited perfect spin-filtering properties. From the electronic states of the nickelocenylferrocene, it was found that the rectification was caused by a difference in the bias-dependent behaviors between the Fe 3d and Ni 3d orbitals.

  16. Nanospherical Brush as Catalase Container for Enhancing the Detection Sensitivity of Competitive Plasmonic ELISA.

    Science.gov (United States)

    Huang, Xiaolin; Chen, Rui; Xu, Hengyi; Lai, Weihua; Xiong, Yonghua

    2016-02-01

    Plasmonic enzyme-linked immunosorbent assay (pELISA) based on catalase (CAT)-mediated gold nanoparticle growth shows great potential for the determination of disease-related biomarkers at ultralow concentrations by using sandwich formats. However, the relatively low sensitivity of this strategy using competitive formats limits its adoption for hapten detection. Herein, we present an improved competitive pELISA for ultrasensitive detection of ochratoxin A (OTA), where silica nanoparticles carrying poly(acrylic acid) brushes (SiO2@PAA) were used to decrease the affinity of competing antigens to anti-OTA monoclonal antibodies and amplify the signal as a "CAT container" (SiO2@PAA@CAT). The developed competitive pELISA exhibits extremely high sensitivity for OTA with detection limits of 10(-18) and 5 × 10(-20) g/mL by the naked eye and microplate reader, respectively. These values are at least 7 orders of magnitude lower than that of competitive CAT-based pELISA (10(-11) g/mL by the naked eye) and 8 orders of magnitude lower than that of horseradish peroxidase-based conventional ELISA (10(-11) g/mL by the microplate reader), respectively. Reliability and robustness of the proposed method were evaluated using actual agricultural products and human serum samples. This study demonstrated the potential of this modified method in practical applications involving the ultrasensitive detection of mycotoxins or other haptens.

  17. Validation of ELISA for the detection of African horse sickness virus antigens and antibodies.

    Science.gov (United States)

    Rubio, C; Cubillo, M A; Hooghuis, H; Sanchez-Vizcaino, J M; Diaz-Laviada, M; Plateau, E; Zientara, S; Crucière, C; Hamblin, C

    1998-01-01

    The mortality rate in susceptible populations of horses during an epizootic of African horse sickness (AHS) may be in excess of 90%. Rapid and reliable assays are therefore essential for the confirmation of clinical diagnoses and to enable control strategies to be implemented without undue delay. One of the major objectives of a recent European Union funded project was the validation of newly developed diagnostic assays which are rapid, sensitive, highly reproducible and inexpensive, for the detection of African horse sickness virus (AHSV) antigens and antibodies. The Laboratorio de Sanidad y Produccion Animal (LSPA) in Algete, Spain was charged with the responsibility of co-ordinating and supplying samples of viruses and antisera to the participating laboratories in Spain, France and the United Kingdom. The panels comprised 76 antigen samples for assay by indirect sandwich ELISAs and 53 serum samples for antibody detection by either indirect or competitive ELISAs. Results generated by ELISA for each laboratory were analysed in LSPA in terms of their relative sensitivities and specificities. There was a good agreement between the ELISAs used for either antigen or antibody detection. The participating groups agreed that any field sample giving a doubtful result would always be retested by ELISA and an alternative assay.

  18. ELISA testing for common food antigens in four dry dog foods used in dietary elimination trials.

    Science.gov (United States)

    Raditic, D M; Remillard, R L; Tater, K C

    2011-02-01

    This study evaluated four over the counter venison dry dog foods available from one on-line retail vendor for potential contamination with common known food allergens: soy, poultry or beef. An amplified, double sandwich type enzyme linked immunosorbent assay (ELISA) test of soy, poultry and beef proteins were performed by an independent accredited food laboratory. The ELISA test for poultry protein was found to be unreliable when testing in dry dog foods because false negatives occurred. ELISA testing of control diets for both soy and beef proteins performed as expected and could be useful in antigen testing in dry dog foods. Three of the four over the counter (OTC) venison canine dry foods with no soy products named in the ingredient list were ELISA positive for soy; additionally one OTC diet tested positive for beef protein with no beef products listed as an ingredient list. One OTC venison diet was not found to be positive for soy, poultry or beef proteins. However, none of the four OTC venison diets could be considered suitable for a diagnostic elimination trial as they all contained common pet food proteins, some of which were readily identifiable on the label and some that were only detected by ELISA. Therefore, if the four OTC venison products selected in this study are representative of OTC products in general, then the use of OTC venison dry dog foods should not be used during elimination trials in suspected food allergy patients. © 2010 Blackwell Verlag GmbH.

  19. Development of a species-specific coproantigen ELISA for human Taenia solium taeniasis.

    Science.gov (United States)

    Guezala, Maria-Claudia; Rodriguez, Silvia; Zamora, Humberto; Garcia, Hector H; Gonzalez, Armando E; Tembo, Alice; Allan, James C; Craig, Philip S

    2009-09-01

    Taenia solium causes human neurocysticercosis and is endemic in underdeveloped countries where backyard pig keeping is common. Microscopic fecal diagnostic methods for human T. solium taeniasis are not very sensitive, and Taenia saginata and Taenia solium eggs are indistinguishable under the light microscope. Coproantigen (CoAg) ELISA methods are very sensitive, but currently only genus (Taenia) specific. This paper describes the development of a highly species-specific coproantigen ELISA test to detect T. solium intestinal taeniasis. Sensitivity was maintained using a capture antibody of rabbit IgG against T. solium adult whole worm somatic extract, whereas species specificity was achieved by utilization of an enzyme-conjugated rabbit IgG against T. solium adult excretory-secretory (ES) antigen. A known panel of positive and negative human fecal samples was tested with this hybrid sandwich ELISA. The ELISA test gave 100% specificity and 96.4% sensitivity for T. solium tapeworm carriers (N = 28), with a J index of 0.96. This simple ELISA incorporating anti-adult somatic and anti-adult ES antibodies provides the first potentially species-specific coproantigen test for human T. solium taeniasis.

  20. Impact properties of aluminium - glass fiber reinforced plastics sandwich panels

    Directory of Open Access Journals (Sweden)

    Mathivanan Periasamy

    2012-06-01

    Full Text Available Aluminium - glass fiber reinforced plastics (GFRP sandwich panels are hybrid laminates consisting of GFRP bonded with thin aluminum sheets on either side. Such sandwich materials are increasingly used in airplane and automobile structures. Laminates with varying aluminium thickness fractions, fiber volume fractions and orientation in the layers of GFRP were fabricated by hand lay up method and evaluated for their impact performance by conducting drop weight tests under low velocity impacts. The impact energy required for initiating a crack in the outer aluminium layer as well as the energy required for perforation was recorded. The impact load-time history was also recorded to understand the failure behavior. The damage depth and the damage area were measured to evaluate the impact resistance. Optical photography and scanning electron micrographs were taken to visualize the crack and the damage zone. The bidirectional cross-ply hybrid laminate (CPHL has been found to exhibit better impact performance and damage resistance than the unidirectional hybrid laminate (UDHL. Increase in aluminium thickness fraction (Al tf and fiber volume fraction (Vf resulted in an increase in the impact energy required for cracking and perforation. On an overall basis, the sandwich panels exhibited better impact performance than the monolithic aluminium.

  1. New "sandwich" structures conformed from three dimensional

    Directory of Open Access Journals (Sweden)

    Alba, Juan J.

    1996-03-01

    Full Text Available Poor interlaminar properties as well as poor-skin-to-core adhesion properties are very often the common existing problems we find when designing with "sandwich" structures. A new type of 3D-fabric "sandwich" structure is being developed in order to avoid these problems. Although the manufacturing process is very simple, a very complex "sandwich" structure is obtained as a result of the complexity of the 3D-fabric used. This 3D-fabric is a 3D woven glass fabric produced on velvet weaving machines with glass yarns. It is an integrally woven "sandwich" laminate for all kinds of composite products. The strength of the vertical fibers makes, that also after impregnation with a resin matrix, the "sandwich" structure is maintained. The result is a laminate with high strength and stiffness and low weight. On each side of this "sandwich" laminate additional reinforcement materials can be laminated and a synthetic foam can be injected in the hollow structure. This will allow to establish the mechanical properties of a finished product.

    Las pobres propiedades, tanto interlaminares como de adhesión entre piel y núcleo, constituyen uno de los grandes problemas cuando se diseñan estructuras utilizando paneles tipo "sandwich". Un nuevo tipo de panel "sandwich", configurado a partir de tejidos tridimensionales, está siendo desarrollado en la actualidad con el objetivo de eliminar esos problemas. Aunque el proceso de fabricación es muy simple, el panel "sandwich" obtenido es de estructura compleja, como resultado de la complejidad del tejido tridimensional utilizado. Este tejido tridimensional (3D es un tejido de fibra de vidrio producido en máquinas de tejer especializadas. La resistencia de las fibras verticales hace que, después de la impregnación con una resina, se mantenga la configuración tipo "sandwich". El resultado es un laminado de alta resistencia, gran rigidez y bajo peso. Sobre cada uno de los lados del panel "sandwich" se pueden

  2. New "sandwich" structures conformed from three dimensional

    OpenAIRE

    1996-01-01

    Poor interlaminar properties as well as poor-skin-to-core adhesion properties are very often the common existing problems we find when designing with "sandwich" structures. A new type of 3D-fabric "sandwich" structure is being developed in order to avoid these problems. Although the manufacturing process is very simple, a very complex "sandwich" structure is obtained as a result of the complexity of the 3D-fabric used. This 3D-fabric is a 3D woven glass fabric produced on velvet weaving machi...

  3. Comparison of electron microscopy, ELISA, real time RT-PCR and insulated isothermal RT-PCR for the detection of Rotavirus group A (RVA) in feces of different animal species.

    Science.gov (United States)

    Soltan, Mohamed A; Tsai, Yun-Long; Lee, Pei-Yu A; Tsai, Chuan-Fu; Chang, Hsiao-Fen G; Wang, Hwa-Tang T; Wilkes, Rebecca P

    2016-09-01

    There is no gold standard for detection of Rotavirus Group A (RVA), one of the main causes of diarrhea in neonatal animals. Sensitive and specific real-time RT-PCR (rtRT-PCR) assays are available for RVA but require submission of the clinical samples to diagnostic laboratories. Patient-side immunoassays for RVA protein detection have shown variable results, particularly with samples from unintended species. A sensitive and specific test for detection of RVA on the farm would facilitate rapid management decisions. The insulated isothermal RT-PCR (RT-iiPCR) assay works in a portable machine to allow sensitive and specific on-site testing. The aim of this investigation was to evaluate a commercially available RT-iiPCR assay for RVA detection in feces from different animal species. This assay was compared to an in-house rtRT-PCR assay and a commercially available rtRT-PCR kit, as well as an ELISA and EM for RVA detection. All three PCR assays targeted the well-conserved NSP5 gene. Clinical fecal samples from 108 diarrheic animals (mainly cattle and horses) were tested. The percentage of positive samples by ELISA, EM, in-house rtRT-PCR, commercial rtRT-PCR, and RT-iiPCR was 29.4%, 31%, 36.7%, 51.4%, 56.9%, respectively. The agreement between different assays was high (81.3-100%) in samples containing high viral loads. The sensitivity of the RT-iiPCR assay appeared to be higher than the commercially available rtRT-PCR assay, with a limit of detection (95% confidence index) of 3-4 copies of in vitro transcribed dsRNA. In conclusion, the user-friendly, field-deployable RT-iiPCR system holds substantial promise for on-site detection of RVA.

  4. Buckling driven debonding in sandwich columns

    DEFF Research Database (Denmark)

    Østergaard, Rasmus Christian

    2008-01-01

    A compression loaded sandwich column that contains a debond is analyzed using a geometrically non-linear finite element model. The model includes a cohesive zone along one face sheet/core interface whereby the debond can extend by interface crack growth. Two geometrical imperfections are introduced......; a global imperfection of the sandwich column axis and a local imperfection of the debonded face sheet axis. The model predicts the sandwich column to be very sensitive to the initial debond length and the local face sheet imperfection. The study shows that the sensitivity to the face sheet imperfection...... results from two mechanisms: (a) interaction of local debond buckling and global buckling and (b) the development of a damaged zone at the debond crack tip. Based on the pronounced imperfection sensitivity, the author predicts that an experimental measurement of the strength of sandwich structures may...

  5. Local slamming impact of sandwich composite hulls

    National Research Council Canada - National Science Library

    Qin, Z; Batra, R.C

    2009-01-01

    We develop a hydroelastic model based on a {3,2}-order sandwich composite panel theory and Wagner's water impact theory for investigating the fluid-structure interaction during the slamming process...

  6. On the Milnor fibers of sandwiched singularities

    OpenAIRE

    Nemethi, Andras; Popescu-Pampu, Patrick

    2009-01-01

    The sandwiched surface singularities are those rational surface singularities which dominate birationally smooth surface singularities. de Jong and van Straten showed that one can reduce the study of the deformations of a sandwiched surface singularity to the study of deformations of a 1-dimensional object, a so-called decorated plane curve singularity. In particular, the Milnor fibers corresponding to their various smoothing components may be reconstructed up to diffeomorphisms from those de...

  7. A Simple ELISA Exercise for Undergraduate Biology.

    Science.gov (United States)

    Baker, William P.; Moore, Cathy R.

    Understanding of immunological techniques such as the Enzyme Linked Immuno Sorbent Assay (ELISA) is an important part of instructional units in human health, developmental biology, microbiology, and biotechnology. This paper describes a simple ELISA exercise for undergraduate biology that effectively simulates the technique using a paper model.…

  8. Aptamer-based Sandwich Assay and its Clinical Outlooks for Detecting Lipocalin-2 in Hepatocellular Carcinoma (HCC)

    Science.gov (United States)

    Lee, Kyeong-Ah; Ahn, Ji-Young; Lee, Sang-Hee; Singh Sekhon, Simranjeet; Kim, Dae-Ghon; Min, Jiho; Kim, Yang-Hoon

    2015-01-01

    We validated a single-stranded, DNA aptamer-based, diagnostic method capable of detecting Lipocalin-2 (LCN2), a biomarker from clinically relevant hepatocellular carcinoma (HCC) patient serum, in the sandwich assay format. Nine aptamers (LCN2_apta1 to LCN2_apta9) for LCN2 were screened with SELEX processes, and a sandwich pair (LCN2_apta2 and LCN2_apta4) was finally chosen using surface plasmon resonance (SPR) and dot blotting analysis. The result of the proposed aptamer sandwich construction shows that LCN2 was sensitively detected in the concentration range of 2.5–500 ng mL−1 with a limit of detection of 0.6 ng mL−1. Quantitative measurement tests in HCC patients were run on straight serum and were compared with the performance of the conventional antibody-based ELISA kit. The aptamer sandwich assay demonstrated an excellent dynamic range for LCN2 at clinically relevant serum levels, covering sub-nanogram per mL concentrations. The new approach offers a simple and robust method for detecting serum biomarkers that have low and moderate abundance. It consists of functionalization, hybridization and signal read-out, and no dilution is required. The results of the study demonstrate the capability of the aptamer sandwich assay platform for diagnosing HCC and its potential applicability to the point-of-care testing (POCT) system. PMID:26039737

  9. [Sb4Au4Sb4]2-: A designer all-metal aromatic sandwich

    Science.gov (United States)

    Tian, Wen-Juan; Guo, Jin-Chang; Li, Da-Zhi; You, Xue-Rui; Wang, Ying-Jin; Sun, Zhong-Ming; Zhai, Hua-Jin

    2016-07-01

    We report on the computational design of an all-metal aromatic sandwich, [Sb4Au4Sb4]2-. The triple-layered, square-prismatic sandwich complex is the global minimum of the system from Coalescence Kick and Minima Hopping structural searches. Following a standard, qualitative chemical bonding analysis via canonical molecular orbitals, the sandwich complex can be formally described as [Sb4]+[Au4]4-[Sb4]+, showing ionic bonding characters with electron transfers in between the Sb4/Au4/Sb4 layers. For an in-depth understanding of the system, one needs to go beyond the above picture. Significant Sb → Au donation and Sb ← Au back-donation occur, redistributing electrons from the Sb4/Au4/Sb4 layers to the interlayer Sb-Au-Sb edges, which effectively lead to four Sb-Au-Sb three-center two-electron bonds. The complex is a system with 30 valence electrons, excluding the Sb 5s and Au 5d lone-pairs. The two [Sb4]+ ligands constitute an unusual three-fold (π and σ) aromatic system with all 22 electrons being delocalized. An energy gap of ˜1.6 eV is predicted for this all-metal sandwich. The complex is a rare example for rational design of cluster compounds and invites forth-coming synthetic efforts.

  10. Application of immunomagnetic particles to enzyme-linked immunosorbent assay (ELISA) for improvement of detection sensitivity of HCG.

    Science.gov (United States)

    Kuo, Hsiao-Ting; Yeh, Jay Z; Wu, Po-Hua; Jiang, Chii-Ming; Wu, Ming-Chang

    2012-01-01

    This investigation was aimed at using superparamagnetic particles to enzyme-linked immunosorbent assay (SPIO-ELISA) of human chorionic gonadotropin (hCG) to enhance detection sensitivity of hCG. We found that N-(3-dimethyl aminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) was the best cross-linking reagent to link anti hCG α antibody to superparamagnetic particle (SPIO-anti hCG α antibody immunomagnetic particle). To improve the specificity of the assay, a horse radish peroxidase (HRP)-labeled anti-hCG beta monoclonal antibody was used to detect captured hCG using double antibody sandwich ELISA assay. SPIO-ELISA application to determine hCG increased the sensitivity to 1 mIU/mL, which is a level of sensitivity enabling the diagnosis of pregnancy during the early gestational period.

  11. Reactions of a 16-electron Cp*Co half-sandwich complex containing a chelating 1,2-dicarba-closo-dodecaborane-1,2-dithiolate ligand with alkynones HC≡C-C(O)R (R=OMe,Me,Ph)

    Institute of Scientific and Technical Information of China (English)

    GUOYIQIBAYI; Gulnisa

    2010-01-01

    The reaction of the 16e half-sandwich complex Cp*Co(S2C2B10H10) (1) (Cp* = pentamethylcyclopentadienyl) with excess methyl acetylene monocarboxylate, HC≡C-CO2Me, affords the 18e complexes 2-6. Compound 2 bears a B-CH2 unit in which B-substitution occurs in the B(3)/B(6) position of the ortho-carborane cage. Complexes 3-6 are geometrical isomers, in which the alkyne is twofold inserted into one of the Co-S bonds in all the four possible ways. Treatment of 1 with excess 3-butyn-2-one or phenyl ethynyl ketone, HC≡C-C(O)R (R = Me, Ph), at ambient temperature leads to the 18e complexes 7-10, respectively, with two alkynes inserted into one of the Co-S bonds. All the new complexes were fully characterized by spectroscopic techniques and elemental analysis. The solid-state structures of 2, 3, 5, 7, 8, 9 and 10 were further characterized by X-ray structural analysis.

  12. Diagnosis of peste des petits ruminants infection in small ruminants through in-house developed Indirect ELISA: Practical considerations

    Directory of Open Access Journals (Sweden)

    K. K. Sharma

    2015-04-01

    Full Text Available Aim: The work was conducted to diagnose peste des petits ruminants (PPR outbreak through an in house developed indirect ELISA (thereafter referred as iELISA its comparison with other available diagnostic tests and description of practical considerations in its development, utility and limitations. Materials and Methods: An outbreak resembled to PPR occurred in two different places of southern Gujarat viz. Vapi and Navsari, affecting 622 animals, including both goat (n = 476 and sheep (n = 146. Animals displayed the typical signs of PPR at Vapi; however diarrhea was the inconsistent feature in animals of Navsari. The affection caused morbidity of 100% and mortality were 73.68% (n = 392/532 and 56.67% (n = 51/90 in Vapi and Navsari outbreaks, respectively. Relevant ante mortem and post mortem samples were collected from representative animals. At the outset of the epidemic no kit was available with us, so agar gel immunodiffusion (AGID was carried out and a commercial ELISA (cELISA kit was ordered for making diagnosis through antibody demonstration. Meanwhile, an iELISA was developed in house using PPR vaccine as antigen and protein G conjugated HRPO antibody as detector. Histopathology and results of sandwich ELISA were also used to diagnose PPR virus (PPRV in the outbreak. Results: The iELISA developed had detected PPRV antibodies in 22/24 samples (91.66%. Significant difference was observed in disease sensitivity pattern of two species by Chi-square test. While AGID failed to detect antibodies in any sample. Results were reconfirmed by comparing with commercially available cELISA kit. Conclusion: PPR is an economically important disease and for the rapid diagnosis of PPR the in house developed antibody capture iELISA can be a suitable cost effective alternative.

  13. A Monoclonal Antibody Based Capture ELISA for Botulinum Neurotoxin Serotype B: Toxin Detection in Food

    Directory of Open Access Journals (Sweden)

    Larry H. Stanker

    2013-11-01

    Full Text Available Botulism is a serious foodborne neuroparalytic disease, caused by botulinum neurotoxin (BoNT, produced by the anaerobic bacterium Clostridium botulinum. Seven toxin serotypes (A–H have been described. The majority of human cases of botulism are caused by serotypes A and B followed by E and F. We report here a group of serotype B specific monoclonal antibodies (mAbs capable of binding toxin under physiological conditions. Thus, they serve as capture antibodies for a sandwich (capture ELISA. The antibodies were generated using recombinant peptide fragments corresponding to the receptor-binding domain of the toxin heavy chain as immunogen. Their binding properties suggest that they bind a complex epitope with dissociation constants (KD’s for individual antibodies ranging from 10 to 48 × 10−11 M. Assay performance for all possible combinations of capture-detector antibody pairs was evaluated and the antibody pair resulting in the lowest level of detection (L.O.D., ~20 pg/mL was determined. Toxin was detected in spiked dairy samples with good recoveries at concentrations as low as 0.5 pg/mL and in ground beef samples at levels as low as 2 ng/g. Thus, the sandwich ELISA described here uses mAb for both the capture and detector antibodies (binding different epitopes on the toxin molecule and readily detects toxin in those food samples tested.

  14. Energy Dissipation in Sandwich Structures During Axial Compression

    DEFF Research Database (Denmark)

    Urban, Jesper

    2002-01-01

    The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full-scale structu......The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full...

  15. Research on EM pulse protection property of plasma-microwave absorptive material-plasma sandwich structure

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A plasma-microwave absorptive material (MAM)-plasma sandwich structure is presented to protect the electronic device against high power electromagnetic pulse. The model of electromagnetic wave reflected by and transmitting through the structure is established. Based on the characteristic parameters of plasma generated by discharge and usual MAM, the electromagnetic transmissive properties of the sandwich structure are investigated by the method of finite difference in time domain. The results indicate that in a rather broad frequency range, the electromagnetic attenuations by the structure are obviously better than the sum of attenuations resulted from plasma and MAM respectively. The models and results presented are instructive for electromagnetic pulse protection.

  16. A multifunctional heat pipe sandwich panel structure

    Energy Technology Data Exchange (ETDEWEB)

    Queheillalt, Douglas T.; Wadley, Haydn N.G. [University of Virginia, Department of Materials Science and Engineering, 140 Chemistry Way, P.O. Box 400745, Charlottesville, VA 22904 (United States); Carbajal, Gerardo [University of Turabo, School of Engineering, P.O. Box 3030, Gurabo 00778 (Puerto Rico); Peterson, G.P. [University of Colorado at Boulder, 914 Broadway, Boulder, CO 80309 (United States)

    2008-01-15

    A multifunctional sandwich panel combining efficient structural load support and thermal management characteristics has been designed and experimentally assessed. The concept is based upon a truncated, square honeycomb sandwich structure. In closed cell honeycomb structures, the transport of heat from one face to the other occurs by a combination of conduction through the webs and convection/radiation within the cells. Here, much more effective heat transport is achieved by multifunctionally utilizing the core as a heat pipe sandwich panel. Its interior consists of a 6061 aluminum truncated-square honeycomb core covered with a stochastic open-cell nickel foam wick. An electroless nickel plating barrier layer inhibited the chemical reaction between the deionized water working fluid and the aluminum structure, retarding the generation of non-condensable hydrogen gas. A thermodynamic model was used to guide the design of the heat pipe sandwich panel. We describe the results of a series of experiments that validate the operational principle of the multifunctional heat pipe sandwich panel and characterize its transient response to an intense localized heat source. The systems measured thermal response to a localized heat source agrees well with that predicted by a finite difference method model used to predict the thermal response. (author)

  17. Sandwich Panels Evaluated With Ultrasonic Spectroscopy

    Science.gov (United States)

    Cosgriff, Laura M.

    2004-01-01

    Enhanced, lightweight material systems, such as 17-4PH stainless steel sandwich panels are being developed for use as fan blades and fan containment systems for next-generation engines. The bond strength between the core and face sheets is critical in maintaining the structural integrity of the sandwich structure. To improve the inspection and production of these systems, researchers at the NASA Glenn Research Center are using nondestructive evaluation (NDE) techniques, such as ultrasonic spectroscopy, to evaluate the brazing quality between the face plates and the metallic foam core. The capabilities and limitations of a swept-frequency approach to ultrasonic spectroscopy were evaluated with respect to these sandwich structures. This report discusses results from three regions of a sandwich panel representing different levels of brazing quality between the outer face plates and a metallic foam core. Each region was investigated with ultrasonic spectroscopy. Then, on the basis of the NDE results, three shear specimens sectioned from the sandwich panel to contain each of these regions were mechanically tested.

  18. ELISA for the serology of FIP virus.

    NARCIS (Netherlands)

    A.D.M.E. Osterhaus (Ab); A. Kroon; R.M.S. Wirahadiredja

    1979-01-01

    textabstractAn enzyme linked immunosorbent assay (ELISA) for feline infectious peritonitis (FIP) virus serology is described. The assay is analogous to a previously developed indirect heterologous immunofluorescence test (IFT) in which transmissible gastroenteritis (TGE) viral antigen was used. Comp

  19. Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

    Directory of Open Access Journals (Sweden)

    Yanil R Parma

    2012-06-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC, a subset of Shiga toxin producing E. coli (STEC is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic uremic syndrome (HUS. Regardless of serotype, Shiga toxins (Stx1 and/or Stx2 are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx was developed using anti-Stx2 B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx2EDL933, stx2vha, stx2vhb, stx2g, stx1EDL933 and stx1d were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 400 ng /ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for 2 strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli.

  20. Radiant heating tests of several liquid metal heat-pipe sandwich panels

    Science.gov (United States)

    Camarda, C. J.; Basiulis, A.

    1983-01-01

    Integral heat pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat load levels. The heat pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low distortion large area structures (e.g., space antennas) and laser mirrors.

  1. Combining photocatalytic hydrogen generation and capsule storage in graphene based sandwich structures

    Science.gov (United States)

    Yang, Li; Li, Xiyu; Zhang, Guozhen; Cui, Peng; Wang, Xijun; Jiang, Xiang; Zhao, Jin; Luo, Yi; Jiang, Jun

    2017-07-01

    The challenge of safe hydrogen storage has limited the practical application of solar-driven photocatalytic water splitting. It is hard to isolate hydrogen from oxygen products during water splitting to avoid unwanted reverse reaction or explosion. Here we propose a multi-layer structure where a carbon nitride is sandwiched between two graphene sheets modified by different functional groups. First-principles simulations demonstrate that such a system can harvest light and deliver photo-generated holes to the outer graphene-based sheets for water splitting and proton generation. Driven by electrostatic attraction, protons penetrate through graphene to react with electrons on the inner carbon nitride to generate hydrogen molecule. The produced hydrogen is completely isolated and stored with a high-density level within the sandwich, as no molecules could migrate through graphene. The ability of integrating photocatalytic hydrogen generation and safe capsule storage has made the sandwich system an exciting candidate for realistic solar and hydrogen energy utilization.

  2. A sandwich enzyme-linked immunosorbent assay for the quantification of insoluble membrane and scaffold proteins.

    Science.gov (United States)

    Geumann, Constanze; Grønborg, Mads; Hellwig, Michaela; Martens, Henrik; Jahn, Reinhard

    2010-07-15

    Enzyme-linked immunosorbent assays (ELISAs) are applied for the quantification of a vast diversity of small molecules. However, ELISAs require that the antigen is present in a soluble form in the sample. Accordingly, the few ELISAs described so far targeting insoluble proteins such as integral membrane and scaffold proteins have been restricted by limited extraction efficiencies and the need to establish an individual solubilization protocol for each protein. Here we describe a sandwich ELISA that allows the quantification of a diverse array of synaptic membrane and scaffold proteins such as munc13-1, gephyrin, NMDA R1 (N-methyl-d-aspartate receptor subunit 1), synaptic vesicle membrane proteins, and SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors). The assay is based on initial solubilization by the denaturing detergent sodium dodecyl sulfate (SDS), followed by partial SDS removal using the detergent Triton X-100, which restores antigenicity while keeping the proteins in solution. Using recombinant standard proteins, we determined assay sensitivities of 78ng/ml to 77pg/ml (or 74-0.1fmol). Calibration of the assay using both immunoblotting and mass spectroscopy revealed that in some cases correction factors need to be included for absolute quantification. The assay is versatile, allows parallel processing and automation, and should be applicable to a wide range of hitherto inaccessible proteins.

  3. Vibro-acoustics of lightweight sandwich structures

    CERN Document Server

    Lu, Tianjian

    2014-01-01

    Vibro-Acoustics of Lightweight Sandwich Structures introduces the study of the coupled vibration and acoustic behavior of lightweight sandwich structures in response to harmonic force and sound pressure. This book focuses on the theoretical modeling and experimental investigation of lightweight sandwich structures in order to provide a predictive framework for vibro-acoustic characteristics of typical engineering structures. Furthermore, by developing solution tools, it concentrates on the influence of key systematic parameters leading to effective guidance for optimal structure design toward lightweight, high-stiffness and superior sound insulation capability. This book is intended for researchers, scientists, engineers and graduate students in mechanical engineering especially in structural mechanics, mechanics and acoustics. Fengxian Xin and Tianjian Lu both work at the School of Aerospace, Xi’an Jiaotong University.

  4. Novel 1-D Sandwich Photonic Bandgap Structure

    Institute of Scientific and Technical Information of China (English)

    庞云波; 高葆新

    2004-01-01

    A sandwich photonic bandgap (PBG) structure is a novel PBG structure whose periodic lattice is buried in the middle of a substrate. Neither drilling nor suspending the substrate is required, and the integrity of the ground plane is maintained. This paper presents several modification techniques for sandwich PBG structure fabrication. The forbidden gap can be improved by adopting the chirping technique, applying the tapering technique, enlarging the periodic elements, adjusting the location of the periodic lattice in the substrate, and using different dielectric media H-shape elements. A finite difference time domain method is applied to analyze the structures. Deep and wide stopbands can be obtained using the modified sandwich structures. Experimental measurement results agree well with the theoretical analysis.

  5. Behaviour of Metal Foam Sandwich Panels

    DEFF Research Database (Denmark)

    2011-01-01

    Sandwich panels as used in structures comprise of a foam core enclosed by thin high strength steel faces. This paper discusses currently design formulae of local buckling behaviour of such panels using the finite element method. Multiple wave finite element models were adopted to investigate...... and examine the adequacy of currently used approach for the design of sandwich panels. The paper presents brief details of the finite element model used including geometry, load pattern and boundary conditions. The selected model gives good agreement with experimental results from Pokharel and Mahendran (2003......). The study shows that currently available design formulae are conservative for stocky sandwich plate elements while being over-conservative for high slenderness. A unified design formula of local buckling behaviour applicable to the full range of slenderness is developed....

  6. Immobilized carboxymethylated dextran coatings for enhanced ELISA.

    Science.gov (United States)

    Liberelle, Benoît; Merzouki, Abderrazzak; De Crescenzo, Gregory

    2013-03-29

    We here report the development of a new generation of enzyme-linked immunosorbent assay (ELISA) that takes advantage of a low-fouling carboxymethylated dextran (CMD) layer chemically grafted on ELISA wells. In our approach, the overnight capture antibody adsorption step found in classical ELISA was replaced by a covalent attachment step to the CMD layer completed in 15 min. As a model, the potential of our approach was highlighted using commercially available anti-human epidermal growth factor (EGF) antibodies to quantify EGF present in various samples. Of interest, the grafted CMD layer was found to be as efficient as the commonly used bovine serum albumine (BSA) to reduce non-specific adsorption, thus eliminating the need of a time-consuming BSA blocking step normally required in classical ELISA. Our results demonstrated similar specificity, affinity, and intra- and inter-assay variations regardless of the diluent used in the assay (BSA-based diluent or protein-free buffer solution) when compared to standard ELISA. Finally, accuracy and precision of the CMD-based ELISA were verified by a spike and recovery test. Dilutions of recombinant human EGF in serum from healthy human volunteers showed almost-perfect linearity and mean recovery rates ranging between 90 and 110%.

  7. Ultra-Lightweight Nanocomposite Foams and Sandwich Structures for Space Structure Applications

    Science.gov (United States)

    Tan, Seng

    2012-01-01

    Microcellular nanocomposite foams and sandwich structures have been created to have excellent electrical conductivity and radiation-resistant properties using a new method that does not involve or release any toxicity. The nanocomposite structures have been scaled up in size to 12 X 12 in. (30 X 30 cm) for components fabrication. These sandwich materials were fabricated mainly from PE, CNF, and carbon fibers. Test results indicate that they have very good compression and compression-after-impact properties, excellent electrical conductivity, and superior space environment durability. Compression tests show that 1000 ESH (equivalent Sun hours) of UV exposure has no effect on the structural properties of the sandwich structures. The structures are considerably lighter than aluminum alloy (= 36 percent lighter), which translates to 36 percent weight savings of the electronic enclosure and its housing. The good mechanical properties of the materials may enable the electronic housing to be fabricated with a thinner structure that further reduces the weight. There was no difficulty in machining the sandwich specimens into electronic enclosure housing.

  8. A rapid sandwich immunoassay for human fetuin A using agarose-3-aminopropyltriethoxysilane modified microtiter plate.

    Science.gov (United States)

    Vashist, Sandeep Kumar; Schneider, E Marion; Luong, John H T

    2015-07-09

    A rapid sandwich immunoassay (IA) with enhanced signal response for human fetuin A (HFA) was developed by modifying the surface of a KOH-treated polystyrene microtiter plate (MTP) with agarose and 3-aminopropyltriethoxysilane (APTES). The agarose-APTES complex binds covalently to the hydroxyl moiety of the MTP plate to serve as a binding platform for bioconjugation of EDC-activated anti-HFA antibody (Ab) via carbodiimide coupling. The one-step kinetics-based sandwich enzyme-linked immunosorbent assay (ELISA) enabled the detection of HFA in 30 min with a limit of detection (LOD) and a linear range of 0.02 ng mL(-1) and 1-243 ng mL(-1), respectively. It detected HFA spiked in diluted human whole blood and serum, and HFA in ethylenediaminetetraacetic acid (EDTA)-plasma of patients with high precision similar to that of conventional ELISA. The anti-HFA Ab-bound agarose-functionalized MTPs retained their functional activity after 6 weeks of storage in 0.1 M PBS, pH 7.4 at 4 °C.

  9. Quantification of human tissue transglutaminase by a luminescence sandwich enzyme-linked immunosorbent assay.

    Science.gov (United States)

    Wolf, Johannes; Lachmann, Ingolf; Wagner, Uta; Osman, Awad A; Mothes, Thomas

    2011-12-15

    Tissue transglutaminase (tTG) is a calcium-dependent enzyme that catalyzes crosslinking of peptidic glutamine residues with primary amines via isopeptide bonds and hydrolysis of ATP or GTP. The enzyme exerts a variety of functions at the cellular and tissue levels that may be disturbed in disease. Its role in pathoprocesses is poorly understood. For investigation of the involvement of tTG in disease, sensitive and specific assays should be available. We have developed the first sandwich enzyme-linked immunosorbent assay (ELISA) based on two monoclonal antibodies (mabs) against human tTG. tTG is captured by mab 3C10 and detected by biotinylated mab 10F3. After incubation with peroxidase-conjugated streptavidin, bound tTG is visualized by peroxidase reaction applying a luminescence substrate. The detection limit was 40 pg/ml. The assay was highly reproducible. Recovery of spiked tTG in crude samples was greater than 92%. The enzyme could be detected in cellular lysates and tissue homogenates of humans. The effect of typical effectors (retinoic acid and interferon-γ) on tTG expression could be demonstrated. A low signal was also obtained in mice samples, suggesting cross-reactivity of the mabs with murine tTG. The new sandwich ELISA may be successfully applied for investigation of physiological functions of tTG and of disorders associated with inadequate tTG expression.

  10. AA, sandwich line with magnetic horn

    CERN Multimedia

    1980-01-01

    The magnetic horn, focusing the antiprotons emanating from the target, was affixed to a sandwich line through which the 150 kA pulses were supplied. Expecting to have to change from time to time the fragile horn (inner conductor only 0.7 mm thick), the assembly was designed for quick exchange. At the lower end of the sandwich line we see the connectors for the high-current cables, at the upper end the magnet horn. It has just been lifted from the V-supports which held it aligned downstream of the target. Continue with 8010293.

  11. Nonlinear dynamic analysis of sandwich panels

    Science.gov (United States)

    Lush, A. M.

    1984-01-01

    Two analytical techniques applicable to large deflection dynamic response calculations for pressure loaded composite sandwich panels are demonstrated. One technique utilizes finite element modeling with a single equivalent layer representing the face sheets and core. The other technique utilizes the modal analysis computer code DEPROP which was recently modified to include transverse shear deformation in a core layer. The example problem consists of a simply supported rectangular sandwich panel. Included are comparisons of linear and nonlinear static response calculations, in addition to dynamic response calculations.

  12. OPTIMAL DESIGN OF QUADRATIC SANDWICH PLATE

    Directory of Open Access Journals (Sweden)

    TIMAR Dr. Imre

    2016-05-01

    Full Text Available In this paper, we show the optimal design of the three-layered sandwich plates. The objective function contains the material and fabrication costs. The design constraints are the maximal stresses, the deflection of plates and damping of vibrations. The unknown is the thickness of the filling foam. By the mathematical method, we define the minima of the cost function and the optimal thickness of the filling layer of foam. The active constraint is the deflection, so we calculate of the costs of the sandwich plate with the homogeneous plate.

  13. Advanced Mechanical Testing of Sandwich Materials

    DEFF Research Database (Denmark)

    Hayman, Brian; Berggreen, Christian; Jenstrup, Claus

    2008-01-01

    An advanced digital optical system has been used to measure surface strains on sandwich face and core specimens tested in a project concerned with improved criteria for designing sandwich X-joints. The face sheet specimens were of glass reinforced polyester and were tested in tension. The core...... specimens were of PVC foam and were tested in compression. The tests were performed in order to validate the use of the measurement system on these materials and to obtain material data for use in numerical simulations. While some limitations were identified, the optical system performed well and appears...

  14. ELISA for complexes between urokinase-type plasminogen activator and its receptor in lung cancer tissue extracts

    DEFF Research Database (Denmark)

    de Witte, H; Pappot, H; Brünner, N

    1997-01-01

    A sandwich-type ELISA has been developed for the assessment of complexes between urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in extracts of squamous cell lung carcinomas. The assay is based on a combination of rabbit polyclonal anti-uPA antibodies and a biotinylated mouse a......PA:uPAR complexes in lung tumor tissue as well as other types of cancer.......A sandwich-type ELISA has been developed for the assessment of complexes between urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in extracts of squamous cell lung carcinomas. The assay is based on a combination of rabbit polyclonal anti-uPA antibodies and a biotinylated mouse...... indicate that de novo complex formation is a major factor to consider and that complexes analyzed in the presence of this antagonist represent original uPA:uPAR complexes present prior to tumor tissue processing. The present ELISA appears suitable for studying the potential prognostic impact of u...

  15. New examples of sandwich gravitational waves and their impulsive limit

    CERN Document Server

    Podolsky, J

    1998-01-01

    Non-standard sandwich gravitational waves are constructed from the homogeneous pp vacuum solution and the motions of free test particles in the space-times are calculated explicitly. They demonstrate the caustic property of sandwich waves. By performing limits to impulsive gravitational wave it is demonstrated that the resulting particle motions are identical regardless of the ''initial'' sandwich.

  16. Non-linear analytical solutions for laterally loaded sandwich plates

    DEFF Research Database (Denmark)

    Riber, Hans Jørgen

    1997-01-01

    This work focuses on the response of orthotropic sandwich composite plates with large deflections due to high lateral loads. The results have special application to the design of ship structures. A geometrical nonlinear theory is outlined, on the basis of the classical sandwich plate theory...... of sandwich plates subjected to high lateral loading. (C) 1997 Published by Elsevier Science Ltd. All rights reserved....

  17. An overview on ELISA techniques for FMD

    Directory of Open Access Journals (Sweden)

    Ding Yao-zhong

    2011-09-01

    Full Text Available Abstract Background FMD is one of the major causes of economic loss of cloven-hoofed animals in the world today. The assessment of dominant genotype/lineage and prevalent trends and confirmation the presence of infection or vaccination not only provides scientific basis and first-hand information for appropriate control measure but also for disease eradication and regaining FMD free status following an outbreak. Although different biological and serological approaches are still applied to study this disease, ELISA test based on the distinct format, antigen type and specific antibody reinforce its predominance in different research areas of FMD, and this may replace the traditional methods in the near future. This review gives comprehensive insight on ELISA currently available for typing, antigenic analysis, vaccination status differentiation and surveillance vaccine purity and content at all stages of manufacture in FMDV. Besides, some viewpoint about the recent advances and trends of ELISA reagent for FMD are described here. Methods More than 100 studies regarding ELISA method available for FMD diagnosis, antigenic analysis and monitor were thoroughly reviewed. We investigated previous sagacious results of these tests on their sensitivity, specificity. Results We found that in all ELISA formats for FMD, antibody-trapping and competitive ELISAs have high specificity and RT-PCR (oligoprobing ELISA has extra sensitivity. A panel of monoclonal antibodies to different sites or monoclonal antibody in combination of antiserum is the most suitable combination of antibodies in ELISA for FMD. Even though from its beginning, 3ABC is proven to be best performance in many studies, no single NSP can differentiate infected from vaccinated animals with complete confidence. Meanwhile, recombinant antigens and peptide derived from FMDV NPs, and NSPs have been developed for use as an alternative to the inactivated virus antigen for security. Conclusions There is

  18. AA, sandwich line with magnetic horn

    CERN Document Server

    1980-01-01

    Continuation from 8010293: Finally, the sandwich line with the horn is placed on the ground, for the horn to be inspected and, if needed, exchanged for a new one. The whole procedure was trained with several members of the AA team, for quick and safe handling, and to share the radiation dose amongst them.

  19. Proof of the Thin Sandwich Conjecture

    CERN Document Server

    Bartnik, R; Bartnik, Robert; Fodor, Gyula

    1993-01-01

    We prove that the Thin Sandwich Conjecture in general relativity is valid, provided that the data $(g_{ab},\\dot g_{ab})$ satisfy certain geometric conditions. These conditions define an open set in the class of possible data, but are not generically satisfied. The implications for the ``superspace'' picture of the Einstein evolution equations are discussed.

  20. Behaviour of Metal Foam Sandwich Panels

    DEFF Research Database (Denmark)

    2011-01-01

    Sandwich panels as used in structures comprise of a foam core enclosed by thin high strength steel faces. This paper discusses currently design formulae of local buckling behaviour of such panels using the finite element method. Multiple wave finite element models were adopted to investigate...

  1. Structural detailing of openings in sandwich panels

    NARCIS (Netherlands)

    Tomà, T.; Courage, W.

    1996-01-01

    European Recommendations exist which provide calculation rules to determine the strength and stiffness of sandwich panels composed of two metal faces with a foam in between. In case of openings in such panels (e.g. for windows) an influence will appear with regard to the stiffness and loadbearing ca

  2. X-joints in composite sandwich panels

    NARCIS (Netherlands)

    Vredeveldt, A.W.; Janssen, G.Th.M.

    1998-01-01

    The small structural weight of fast large ships such as fast mono hulls or catamaran type of ships is of extreme importance to their success. One possible light weight structural solution is the sandwich panel with fibre reinforced laminates and a balsa, honeycomb or foam core. A severe obstacle for

  3. Organometallic half-sandwich iridium anticancer complexes

    NARCIS (Netherlands)

    Liu, Z.; Habtemariam, A.; Pizarro, A.M.; Fletcher, S.A.; Kisova, A.; Vrana, O.; Salassa, L.; Bruijnincx, P.C.A.|info:eu-repo/dai/nl/33799529X; Clarkson, G.J.; Brabec, V.; Sadler, Peter J.

    2011-01-01

    The low-spin 5d6 IrIII organometallic half-sandwich complexes [(η5-Cpx)Ir(XY)Cl]0/+, Cpx = Cp*, tetramethyl(phenyl)cyclopentadienyl (Cpxph), or tetramethyl(biphenyl)cyclopentadienyl (Cpxbiph), XY = 1,10-phenanthroline (4−6), 2,2′-bipyridine (7−9), ethylenediamine (10 and 11), or picolinate (12−14),

  4. Feedback Sandwiches Affect Perceptions but Not Performance

    Science.gov (United States)

    Parkes, Jay; Abercrombie, Sara; McCarty, Teresita

    2013-01-01

    The feedback sandwich technique-make positive comments; provide critique; end with positive comments-is commonly recommended to feedback givers despite scant evidence of its efficacy. These two studies (N = 20; N = 350) of written peer feedback with third-year medical students on clinical patient note-writing assignments indicate that students…

  5. X-joints in composite sandwich panels

    NARCIS (Netherlands)

    Vredeveldt, A.W.; Janssen, G.Th.M.

    1998-01-01

    The small structural weight of fast large ships such as fast mono hulls or catamaran type of ships is of extreme importance to their success. One possible light weight structural solution is the sandwich panel with fibre reinforced laminates and a balsa, honeycomb or foam core. A severe obstacle for

  6. Transferability of antibody pairs from ELISA to fiber optic surface plasmon resonance for infliximab detection

    Science.gov (United States)

    Van Stappen, Thomas; Lu, Jiadi; Bloemen, Maarten; Geukens, Nick; Spasic, Dragana; Delport, Filip; Verbiest, Thierry; Lammertyn, Jeroen; Gils, Ann

    2015-03-01

    Tumor necrosis factor (TNF)-alpha is a pleiotropic cytokine up-regulated in inflammatory bowel disease, rheumatoid arthritis and psoriasis. The introduction of anti-TNF drugs such as infliximab has revolutionized the treatment of these diseases. Recently, therapeutic drug monitoring (TDM) of infliximab has been introduced in clinical decision making to increase cost-efficiency. Nowadays, TDM is performed using radio-immunoassays, homogeneous mobility shift assays or ELISA. Unfortunately, these assays do not allow for in situ treatment optimization, because of the required sample transportation to centralized laboratories and the subsequent assay execution time. In this perspective, we evaluated the potential of fiber optic-surface plasmon resonance (FO-SPR). To achieve this goal, a panel of 55 monoclonal anti-infliximab antibodies (MA-IFX) was developed and characterized in-house, leading to the identification of nine different clusters. Based on this high diversity, 22 antibody pairs were selected and tested for their reactivity towards IFX, using one MA-IFX as capture and one MA-IFX for detection, in a sandwich type ELISA and FO-SPR. This study showed that the reactivity towards IFX of each antibody pair in ELISA is highly similar to its reactivity on FO-SPR, indicating that antibody pairs are easily transferable between both platforms. Given the fact that FO-SPR shows the potential for miniaturization and fast assay time, it can be considered a highly promising platform for on-site infliximab monitoring.

  7. Development of an ELISA kit using monoclonal antibody to Clostridium difficile toxin A

    Institute of Scientific and Technical Information of China (English)

    Si-Wu Fu; Ya-Li Zhang; Dian-Yuan Zhou

    2004-01-01

    AIM: To establish an ELISA kit using monoclonal antibodiesagainst Clostridium difficile ( C. difficile) toxin A.METHODS: An indirect sandwich ElISA was described using the purified rabbit monospecific antiserum as capturing antibody. After the polystyrene microtitre plates with 96 fiat-bottomed wells were coated with rabbit antiserum, the wells were blocked with 100 g/L BSA in PBS-T. C. difficiletoxin A or culture filtrates were added to each well and then monoclonal antibodies IgG-horseradish peroxidase conjugate was added as detecting antibody, tetramethylbenzidine was used as substrate and A450 of the stopped reacting product was recorded in an automated plate reader. RESULTS: The tested specimens included culture filtrates of 2 strains of toxigenic C. difficile, 2 strains of non-toxigenic C. difficile, 26 strains of E. coli, 2 strains of S. dysenteriae, 1 strain of Bif infantis, 5 strains of V. cholera, 2 strains ofS. typhi, 7 strains of C. botulinum, 1 strain of toxigenic C. sordllii, and 1 strain of C. butyricum. A total of 47 strains of culture filtrates were all negative except for 2 strains of toxigenic C. difficile. The detective limitation of toxin A was 0.1 ng/mL.CONCLUSION: An ELISA kit with high specificity and excellent sensitivity for the rapid detection of C. difficile toxin A was established. It will be a useful tool for diagnostic test of C. difficile toxin A.

  8. Development of an ELISA for evaluation of swab recovery efficiencies of bovine serum albumin.

    Directory of Open Access Journals (Sweden)

    Nadja Sparding

    Full Text Available After a potential biological incident the sampling strategy and sample analysis are crucial for the outcome of the investigation and identification. In this study, we have developed a simple sandwich ELISA based on commercial components to quantify BSA (used as a surrogate for ricin with a detection range of 1.32-80 ng/mL. We used the ELISA to evaluate different protein swabbing procedures (swabbing techniques and after-swabbing treatments for two swab types: a cotton gauze swab and a flocked nylon swab. The optimal swabbing procedure for each swab type was used to obtain recovery efficiencies from different surface materials. The surface recoveries using the optimal swabbing procedure ranged from 0-60% and were significantly higher from nonporous surfaces compared to porous surfaces. In conclusion, this study presents a swabbing procedure evaluation and a simple BSA ELISA based on commercial components, which are easy to perform in a laboratory with basic facilities. The data indicate that different swabbing procedures were optimal for each of the tested swab types, and the particular swab preference depends on the surface material to be swabbed.

  9. HYBRID-SANDWICHED REINFORCEMENT WITH GEOSYNTHETICS

    Science.gov (United States)

    Yasuhara, Kazuya; Yamazaki, Shinji; Sakakibara, Tsutomu

    Advantageous aspects of sandwich-type reinforced earth structures combined with geosynthetics and sand mat are highlighted in this paper. Those aspects were elucidated by two kinds of laboratory tests : (1) large consolidation tests for improvement of hydraulic conductivity and (2) model footing tests on improvement of bearing capacity and deformation characteristics for reinforced earth structures, including both vertical permeability and horizontal transmissibility characteristics of geosynthetics results from both laboratory tests indicated the following: i) Hydraulic conductivity of geosynthetics used for this type of earth reinforcement can be maintained for a long period. Such conductivity sometimes disappears, particularly because of clogging when geosynthetics are adopted in embankment construction using fine-grained soils. This fact indicates that the sand mats which are laid above and beneath geosynthetics play a salient role in preventing clogging of geosynthetics that occurs by intrusion of fines from cohesive soils. ii) Sandwich-type reinforcement combined with geosynthetics and sand mats increases stability and decreases deformation of earth structures. In particular, the sandwich structure is effective for providing toughness, which has remained an important issue for reducing infrastructural maintenance and costs. In the later part of the paper, conventionally available stability analysis was carried out to propose the design procedure for reinforced earth structures and at the same time numerical analysis was also conducted to ensure the applicability of the hybrid-sandwiched earth reinforcement newly proposed in the current paper. Finally, based on the horizontal placement by means of HBS described in the current paper, the vertical drain procedure using the sandwich structures for accelerating consolidation and increasing stability of soft soils is also suggested for the future research and investigation.

  10. Structural Analysis of Sandwich Foam Panels

    Energy Technology Data Exchange (ETDEWEB)

    Kosny, Jan [ORNL; Huo, X. Sharon [Tennessee Technological University

    2010-04-01

    The Sandwich Panel Technologies including Structural Insulated Panels (SIPs) can be used to replace the conventional wooden-frame construction method. The main purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and SGI Venture, Inc. was to design a novel high R-value type of metal sandwich panelized technology. This CRADA project report presents design concept discussion and numerical analysis results from thermal performance study of this new building envelope system. The main objective of this work was to develop a basic concept of a new generation of wall panel technologies which will have R-value over R-20 will use thermal mass to improve energy performance in cooling dominated climates and will be 100% termite resistant. The main advantages of using sandwich panels are as follows: (1) better energy saving structural panels with high and uniform overall wall R-value across the elevation that could not be achieved in traditional walls; and (2) reducing the use of raw materials or need for virgin lumber. For better utilization of these Sandwich panels, engineers need to have a thorough understanding of the actual performance of the panels and system. Detailed analysis and study on the capacities and deformation of individual panels and its assembly have to be performed to achieve that goal. The major project activity was to conduct structural analysis of the stresses, strains, load capacities, and deformations of individual sandwich components under various load cases. The analysis simulated the actual loading conditions of the regular residential building and used actual material properties of the steel facings and foam.

  11. Pemendekan Waktu ELISA dalam Deteksi TMV

    Directory of Open Access Journals (Sweden)

    Susamto Somowiyarjo

    1996-12-01

    Full Text Available In order to support the program for the management of viral diseases on garlic, a rapid diagnosis procedure was developed by shortening the incubation period of the indirect ELISA. No significant differences of ELISA absorbance were observed when the antigen was incubated for 4 h, 2 h, and 30 min at 37ºC. The incubation period for the antibody and conjugate could he reduced from 4 h at 37ºC or 18 h at 4ºC to 30 min al 37ºC. The shortest period of incubation for the assay could be obtained when each incubation time for the antigen, antibody and conjugate was 30 min. The detection limit for the shortened ELISA was 10^-4 for the virus in crude extracts and 0,5 μg/ml for the purified preparation.

  12. A sensitive high throughput ELISA for human eosinophil peroxidase: a specific assay to quantify eosinophil degranulation from patient-derived sources.

    Science.gov (United States)

    Ochkur, Sergei I; Kim, John Dongil; Protheroe, Cheryl A; Colbert, Dana; Condjella, Rachel M; Bersoux, Sophie; Helmers, Richard A; Moqbel, Redwan; Lacy, Paige; Kelly, Elizabeth A; Jarjour, Nizar N; Kern, Robert; Peters, Anju; Schleimer, Robert P; Furuta, Glenn T; Nair, Parameswaran; Lee, James J; Lee, Nancy A

    2012-10-31

    Quantitative high throughput assays of eosinophil-mediated activities in fluid samples from patients in a clinical setting have been limited to ELISA assessments for the presence of the prominent granule ribonucleases, ECP and EDN. However, the demonstration that these ribonucleases are expressed by leukocytes other than eosinophils, as well as cells of non-hematopoietic origin, limits the usefulness of these assays. Two novel monoclonal antibodies recognizing eosinophil peroxidase (EPX) were used to develop an eosinophil-specific and sensitive sandwich ELISA. The sensitivity of this EPX-based ELISA was shown to be similar to that of the commercially available ELISA kits for ECP and EDN. More importantly, evidence is also presented confirming that among these granule protein detection options, EPX-based ELISA is the only eosinophil-specific assay. The utility of this high throughput assay to detect released EPX was shown in ex vivo degranulation studies with isolated human eosinophils. In addition, EPX-based ELISA was used to detect and quantify eosinophil degranulation in several in vivo patient settings, including bronchoalveolar lavage fluid obtained following segmental allergen challenge of subjects with allergic asthma, induced sputum derived from respiratory subjects following hypotonic saline inhalation, and nasal lavage of chronic rhinosinusitis patients. This unique EPX-based ELISA thus provides an eosinophil-specific assay that is sensitive, reproducible, and quantitative. In addition, this assay is adaptable to high throughput formats (e.g., automated assays utilizing microtiter plates) using the diverse patient fluid samples typically available in research and clinical settings.

  13. A Colorimetric Enzyme-Linked Immunosorbent Assay (ELISA) Detection Platform for a Point-of-Care Dengue Detection System on a Lab-on-Compact-Disc.

    Science.gov (United States)

    Thiha, Aung; Ibrahim, Fatimah

    2015-05-18

    The enzyme-linked Immunosorbent Assay (ELISA) is the gold standard clinical diagnostic tool for the detection and quantification of protein biomarkers. However, conventional ELISA tests have drawbacks in their requirement of time, expensive equipment and expertise for operation. Hence, for the purpose of rapid, high throughput screening and point-of-care diagnosis, researchers are miniaturizing sandwich ELISA procedures on Lab-on-a-Chip and Lab-on-Compact Disc (LOCD) platforms. This paper presents a novel integrated device to detect and interpret the ELISA test results on a LOCD platform. The system applies absorption spectrophotometry to measure the absorbance (optical density) of the sample using a monochromatic light source and optical sensor. The device performs automated analysis of the results and presents absorbance values and diagnostic test results via a graphical display or via Bluetooth to a smartphone platform which also acts as controller of the device. The efficacy of the device was evaluated by performing dengue antibody IgG ELISA on 64 hospitalized patients suspected of dengue. The results demonstrate high accuracy of the device, with 95% sensitivity and 100% specificity in detection when compared with gold standard commercial ELISA microplate readers. This sensor platform represents a significant step towards establishing ELISA as a rapid, inexpensive and automatic testing method for the purpose of point-of-care-testing (POCT) in resource-limited settings.

  14. A Colorimetric Enzyme-Linked Immunosorbent Assay (ELISA Detection Platform for a Point-of-Care Dengue Detection System on a Lab-on-Compact-Disc

    Directory of Open Access Journals (Sweden)

    Aung Thiha

    2015-05-01

    Full Text Available The enzyme-linked Immunosorbent Assay (ELISA is the gold standard clinical diagnostic tool for the detection and quantification of protein biomarkers. However, conventional ELISA tests have drawbacks in their requirement of time, expensive equipment and expertise for operation. Hence, for the purpose of rapid, high throughput screening and point-of-care diagnosis, researchers are miniaturizing sandwich ELISA procedures on Lab-on-a-Chip and Lab-on-Compact Disc (LOCD platforms. This paper presents a novel integrated device to detect and interpret the ELISA test results on a LOCD platform. The system applies absorption spectrophotometry to measure the absorbance (optical density of the sample using a monochromatic light source and optical sensor. The device performs automated analysis of the results and presents absorbance values and diagnostic test results via a graphical display or via Bluetooth to a smartphone platform which also acts as controller of the device. The efficacy of the device was evaluated by performing dengue antibody IgG ELISA on 64 hospitalized patients suspected of dengue. The results demonstrate high accuracy of the device, with 95% sensitivity and 100% specificity in detection when compared with gold standard commercial ELISA microplate readers. This sensor platform represents a significant step towards establishing ELISA as a rapid, inexpensive and automatic testing method for the purpose of point-of-care-testing (POCT in resource-limited settings.

  15. Radiolinja, Vodafone või Elisa

    Index Scriptorium Estoniae

    2004-01-01

    Jüri Kaljundi, Tarvo Ulejev ning Anne Mere vastavad küsimusele, kas Radiolinja peaks jätma alles olemasoleva nime, võtma nimeks Soomes peagi Radiolinjat asendama hakkava Elisa või rahvusvaheliselt tuntud kaubamärgi Vodafone

  16. On-Surface Synthesis of Sandwich Molecular Nanowires on Graphene.

    Science.gov (United States)

    Huttmann, Felix; Schleheck, Nicolas; Atodiresei, Nicolae; Michely, Thomas

    2017-07-26

    We demonstrate a new synthesis route for the growth of organometallic sandwich molecular nanowires, taking the example of Eu-cyclooctatetraene (EuCot), a predicted ferromagnetic semiconductor. We employ simultaneous exposure of Cot molecules and Eu vapor in ultrahigh vacuum to an inert substrate, such as graphene. Using a Cot excess under temperature conditions of a finite residence time of the molecule, the reactand diffusion confined to two dimensions results in a clean product of ultralong wires. In situ scanning tunneling microscopy reveals not only their molecular structure but also a rich and intriguing growth morphology. The new on-surface synthesis permits experimental access to a largely unexplored class of one-dimensional organometallic systems with potential for exciting electronic and magnetic properties.

  17. On the Milnor fibers of sandwiched singularities

    CERN Document Server

    Nemethi, Andras

    2009-01-01

    The sandwiched surface singularities are those rational surface singularities which dominate birationally smooth surface singularities. de Jong and van Straten showed that one can reduce the study of the deformations of a sandwiched surface singularity to the study of deformations of a 1-dimensional object, a so-called decorated plane curve singularity. In particular, the Milnor fibers corresponding to their various smoothing components may be reconstructed up to diffeomorphisms from those deformations of associated decorated curves which have only ordinary singularities. Part of the topology of such a deformation is encoded in the incidence matrix between the irreducible components of the deformed curve and the points which decorate it, well-defined up to permutations of columns. Extending a previous theorem ofours, which treated the case of cyclic quotient singularities, we show that the Milnor fibers which correspond to deformations whose incidence matrices are different up to permutations of columns are n...

  18. Utilization of Bamboo as Lightweight Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Suthon SRIVARO

    2016-05-01

    Full Text Available Lightweight sandwich panels consisting of bamboo faces and oil palm trunk core were manufactured using melamine urea formaldehyde with the resin content of 250 g/m2 (solid basis. The parameters examined were node and density of bamboo faces. Physical (board density, thickness swelling and water absorption and mechanical (modulus of elasticity and modulus of rupture properties of the sandwich board obtained were investigated and compared with other bamboo products and commercial wood based products. Result showed that this panel had better dimensional stability than those of other bamboo products but lower bending strength. Node of bamboo had no significant effect on any board properties examined. Most of board properties were influenced by bamboo face density. Comparing the properties to commercial wood based products, this panel could be used as wall/floor applications.

  19. Ultrasonic Spectroscopy of Stainless Steel Sandwich Panels

    Science.gov (United States)

    Cosgriff, Laura M.; Lerch, Bradley A.; Hebsur, Mohan G.; Baaklini, George Y.; Ghosn, Louis J.

    2003-01-01

    Enhanced, lightweight material systems, such as 17-4PH stainless steel sandwich panels are being developed for use as fan blades and fan containment material systems for next generation engines. In order to improve the production for these systems, nondestructive evaluation (NDE) techniques, such as ultrasonic spectroscopy, are being utilized to evaluate the brazing quality between the 17-4PH stainless steel face plates and the 17-4PH stainless steel foam core. Based on NDE data, shear tests are performed on sections representing various levels of brazing quality from an initial batch of these sandwich structures. Metallographic characterization of brazing is done to corroborate NDE findings and the observed shear failure mechanisms.

  20. Buckling optimisation of sandwich cylindrical panels

    Science.gov (United States)

    Abouhamzeh, M.; Sadighi, M.

    2016-06-01

    In this paper, the buckling load optimisation is performed on sandwich cylindrical panels. A finite element program is developed in MATLAB to solve the governing differential equations of the global buckling of the structure. In order to find the optimal solution, the genetic algorithm Toolbox in MATLAB is implemented. Verifications are made for both the buckling finite element code and also the results from the genetic algorithm by comparisons to the results available in literature. Sandwich cylindrical panels are optimised for the buckling strength with isotropic or orthotropic cores with different boundary conditions. Results are presented in terms of stacking sequence of fibers in the face sheets and core to face sheet thickness ratio.

  1. Utilization of Bamboo as Lightweight Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Suthon SRIVARO

    2016-05-01

    Full Text Available Lightweight sandwich panels consisting of bamboo faces and oil palm trunk core were manufactured using melamine urea formaldehyde with the resin content of 250 g/m2 (solid basis. The parameters examined were node and density of bamboo faces. Physical (board density, thickness swelling and water absorption and mechanical (modulus of elasticity and modulus of rupture properties of the sandwich board obtained were investigated and compared with other bamboo products and commercial wood based products. Result showed that this panel had better dimensional stability than those of other bamboo products but lower bending strength. Node of bamboo had no significant effect on any board properties examined. Most of board properties were influenced by bamboo face density. Comparing the properties to commercial wood based products, this panel could be used as wall/floor applications.

  2. Novel polyclonal-monoclonal-based ELISA utilized to examine lupine (Lupinus species) content in food products.

    Science.gov (United States)

    Holden, Lise; Moen, Lena Haugland; Sletten, Gaynour B G; Dooper, Maaike M B W

    2007-04-04

    Sweet lupines are increasingly used in food production. Cause for concern has been expressed due to the increase in reported lupine-induced allergic incidents and the association between lupine and peanut allergies. In the current study, a polyclonal-monoclonal antibody-based sandwich ELISA for the detection of lupine proteins in foods was developed. The assay was sensitive to both native and processed proteins from Lupinus angustifolius and Lupinus albus and had a detection limit of 1 mug/g. Intra- and interassay coefficients of variation were lupine declaration, was evaluated for their content of lupine. The data showed that the majority were in agreement with the respective labeling. However, some inconsistency was seen, typically in bread/rolls and soy flours.

  3. Rheumatoid factor interference of α-fetoprotein evaluations in human serum by ELISA.

    Science.gov (United States)

    Zhu, Xiaoxia; Yuyingguo; Huang, Zhenyun; Yang, Shumei

    2014-01-01

    Serum a-fetoprotein (AFP) is one of the most common diagnostic markers for hepatocellular cancer (HCC) in the laboratory. As other immunoassays, AFP determination is not free from interferences. Natural antibodies like rheumatoid factors (RFs) may induce falsely elevated results, leading to misdiagnosis and expensive unnecessary explorations. Serum samples containing AFP were spiked with moderate- or high-concentration RFs, and samples with high RF levels were spiked with AFP. The original sera, as well as the mixtures were tested for AFP by one-step and two-step sandwich ELISA. In the spiked specimens, addition of RFs caused significant bias in the measurement of AFP. The threshold for triggering significant interference was 260 IU/mL for RFs and 74 ng/mL for AFP. In studies on the prevalence and clinical significance of serum AFP, RF interference should be considered and RF testing should be performed.

  4. Antigen capture ELISA system for henipaviruses using polyclonal antibodies obtained by DNA immunization.

    Science.gov (United States)

    Kaku, Yoshihiro; Noguchi, Akira; Marsh, Glenn A; Barr, Jennifer A; Okutani, Akiko; Hotta, Kozue; Bazartseren, Boldbaatar; Broder, Christopher C; Yamada, Akio; Inoue, Satoshi; Wang, Lin-Fa

    2012-08-01

    A novel antigen-capture sandwich ELISA system targeting the glycoproteins of the henipaviruses Nipah virus (NiV) and Hendra virus (HeV) was developed. Utilizing purified polyclonal antibodies derived from NiV glycoprotein-encoding DNA-immunized rabbits, we established a system that can detect the native antigenic structures of the henipavirus surface glycoproteins using simplified and inexpensive methods. The lowest detection limit against live viruses was achieved for NiV Bangladesh strain, 2.5 × 10(4) TCID(50). Considering the recent emergence of genetic variants of henipaviruses and the resultant problems that arise for PCR-based detection, this system could serve as an alternative rapid diagnostic and detection assay.

  5. A spiral antenna sandwiched by dielectric layers

    OpenAIRE

    Nakano, Hisamatsu; Ikeda, Masakazu; Hitosugi, Kazuo; Yamauchi, Junji

    2004-01-01

    An infinitesimally thin spiral antenna, sandwiched by bottom and top dielectric layers having the same relative permittivity, is analyzed under the condition that the dielectric layers are of finite extent and the antenna is backed by an infinite conducting plane. As the thickness of the top dielectric layer increases, the input impedance and axial ratio (AR) vary in an oscillatory fashion, with a period slightly larger than one-half of the guided wavelength of a wave propagating in an unboun...

  6. Immunodetection of Triticum mosaic virus by DAS- and DAC-ELISA using antibodies produced against coat protein expressed in Escherichia coli: potential for high-throughput diagnostic methods.

    Science.gov (United States)

    Tatineni, Satyanarayana; Sarath, Gautam; Seifers, Dallas; French, Roy

    2013-04-01

    Triticum mosaic virus (TriMV), an economically important virus infecting wheat in the Great Plains region of the USA, is the type species of the Poacevirus genus in the family Potyviridae. Sensitive and high-throughput serology-based detection methods are crucial for the management of TriMV and germplasm screening in wheat breeding programs. In this study, TriMV coat protein (CP) was expressed in Escherichia coli, and polyclonal antibodies were generated against purified soluble native form recombinant CP (rCP) in rabbits. Specificity and sensitivity of resulting antibodies were tested in Western immuno-blot and enzyme-linked immunosorbent assays (ELISA). In direct antigen coating (DAC)-ELISA, antibodies reacted specifically, beyond 1:20,000 dilution with TriMV in crude sap, but not with healthy extracts, and antiserum at a 1:10,000 dilution detected TriMV in crude sap up to 1:4860 dilution. Notably, rabbit anti-TriMV IgG and anti-TriMV IgG-alkaline phosphatase conjugate reacted positively with native virions in crude sap in a double antibody sandwich-ELISA, suggesting that these antibodies can be used as coating antibodies which is crucial for any 'sandwich' type of assays. Finally, the recombinant antibodies reacted positively in ELISA with representative TriMV isolates collected from fields, suggesting that antibodies generated against rCP can be used for sensitive, large-scale, and broad-spectrum detection of TriMV.

  7. Self-healing sandwich composite structures

    Science.gov (United States)

    Fugon, D.; Chen, C.; Peters, K.

    2012-04-01

    Previous research demonstrated that a thin self-healing layer is effective in recovering partial sandwich composite performance after an impact event. Many studies have been conducted that show the possibility of using Fiber Bragg Grating (FBG) sensors to monitor the cure of a resin through strain and temperature monitoring. For this experiment, FBG sensors were used to monitor the curing process of a self-healing layer within a twelve-layer fiberglass laminate after impact. First, five self-healing sandwich composite specimens were manufactured. FBG sensors were embedded between the fiberglass and foam core. Then the fiberglass laminate was impacted with the use of a drop tower and the curing process was monitored. The collected data was used to compare the cure of the resin and fiberglass alone to the cure of the resin from a self-healing specimen. For the low viscosity resin system tested, these changes were not sufficiently large to identify different polymerization states in the resin as it cured. These results indicate that applying different resin systems might increase the efficiency of the self-healing in the sandwich composites.

  8. Mixed auxeticity of auxetic sandwich structures

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Teik-Cheng [SIM University, Singapore (Singapore)

    2012-07-15

    Previously, a sandwich structure in which the Poisson ratios of the core and facesheets possess opposite signs has been shown to exhibit overall conventional and auxetic behavior depending on the loading mode - axial loading or bending - for an intermediate range of relative core thickness. In addition to these two loading modes, sandwich structures in aerospace applications encounter torsional loads. In this paper, the effective Poisson's ratio for torsional loading is proposed. Results show that, depending on the loading mode and the relative core thickness, there can be up to four levels of overall auxeticity, namely (i) full auxeticity (FA) if the structure behaves as an auxetic structure under all three modes of loading, (ii) high auxeticity (HA) if the structure behaves as an auxetic structure in two of the loading modes, (iii) low auxeticity (LA) if the structure behaves as an auxetic structure in only one of the loading modes, and (iv) no auxeticity (NA) if the structure behaves as a conventional structure under all of the three loading modes. These results indicate that by selecting the Poisson's ratios and the thickness of the cores and facesheets, the sandwich structure can be made to respond differently under different external loading conditions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Unique Sandwiched Carbon Sheets@Ni-Mn Nanoparticles for Enhanced Oxygen Evolution Reaction.

    Science.gov (United States)

    Zhang, Yan; Zhang, Huijuan; Yang, Jiao; Bai, Yuanjuan; Qiu, Huajun; Wang, Yu

    2016-05-11

    A unique sandwich-like architecture, where Ni-Mn nanoparticles are enveloped in coupled carbon sheets (CS@Ni-Mn), has been successfully fabricated. In the synthesis process, a great quantity of uniform NiMnO3 nanosheets generated by a universal hydrothermal method acts as precursors and templates and the cheap, environmentally friendly and recyclable glucose functions as a green carbon source. Via subsequent hydrothermal reaction and thermal annealing, sandwiched nanocomposites with Ni-Mn nanoparticles embedded inside and carbon sheets encapsulating outside can be massively prepared. The novel sandwich-like CS@Ni-Mn possesses numerous advantages, such as an intrinsic porous feature, large specific surface area, and enhanced electronic conductivity. Moreover, as a promising NiMn-based oxygen evolution reaction (OER) catalyst, the special sandwiched nanostructure demonstrates improved electrochemical properties in 1 M KOH, including a low overpotential of about 250 mV, a modest Tafel slope of 40 mV dec(-1), excellent stability over 2000 cycles, and durability for 40 h.

  10. Photocatalytic perfermance of sandwich-like BiVO4 sheets by microwave assisted synthesis

    Science.gov (United States)

    Liu, Suqin; Tang, Huiling; Zhou, Huan; Dai, Gaopeng; Wang, Wanqiang

    2017-01-01

    Sandwich-like BiVO4 sheets were successfully synthesized in an aqueous solution containing bismuth nitrate, ammonium metavanadate and polyethylene glycol with a molecular weight of 10,000 (PEG-10000) using a facile microwave-assisted method. The as-prepared samples were characterized by scanning electron microscopy, N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy. The results show that the presence of PEG-10000 plays a critical role in the formation of BiVO4 sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO4 sheets exhibit a high activity for the degradation of methyl orange under visible light irradiation (λ ≥ 420 nm). The enhancement of photocatalytic activity of sandwich-like BiVO4 sheets can be attributed to its large surface area over the irregular BiVO4 particles.

  11. Enhanced electrochemical performance from 3DG/LiFePO4/G sandwich cathode material

    Science.gov (United States)

    Du, Yahui; Tang, Yufeng; Chang, Chengkang

    2017-08-01

    In this paper, we have successfully synthesized a three dimensional graphene/LiFePO4/graphene (3DG/LFP/G) sandwich composite by an in-situ hydrothermal method, in which chemical vapor deposited 3D graphene acts as the high conductivity supporting framework, while the LiFePO4 nanoparticles are anchored onto the 3D graphene framework covered by graphene sheets. XRD and SEM results confirmed the formation of the 3DG/LFP/G sandwich composite. Cyclic Voltammetry curve of the sandwich composite shows sharper redox peaks and reduced voltage separation when compared to the reference electrodes, suggesting high specific capacity and good rate performance. Further charge/discharge measurements presented high capacity of 164 mAh g-1 at 0.2 C and 124 mAh g-1 at 10 C (75.7% of its initial capacity) for the sandwich composite, with capacity retention of 95.7% after 100 cycles, implying potential application in lithium ion battery at high rates. The EIS investigation suggests that both the electronic conductivity and the Li ion diffusion are promoted by the underlined 3D graphene framework, which is regarded as the reason for the enhanced electrochemical performance.

  12. Development of monoclonal antibodies and quantitative ELISAs targeting insulin-degrading enzyme

    Directory of Open Access Journals (Sweden)

    Dickson Dennis W

    2009-10-01

    Full Text Available Abstract Background Insulin-degrading enzyme (IDE is a widely studied zinc-metalloprotease implicated in the pathogenesis of type 2 diabetes mellitus, Alzheimer disease (AD and varicella zoster virus infection. Despite more than six decades of research on IDE, progress has been hampered by the lack of well-characterized reagents targeting this biomedically important protease. To address this important need, we generated and characterized new mouse monoclonal antibodies (mAbs targeting natively folded human and rodent IDE. Results Eight monoclonal hybridoma cell lines were derived in house from mice immunized with full-length, natively folded, recombinant human IDE. The mAbs derived from these lines were shown to detect IDE selectively and sensitively by a wide range of methods. Two mAbs in particular—designated 6A1 and 6H9—proved especially selective for IDE in immunocytochemical and immunohistochemical applications. Using a variety of methods, we show that 6A1 selectively detects both human and rodent IDE, while 6H9 selectively detects human, but not rodent, IDE, with both mAbs showing essentially no cross reactivity with other proteins in these applications. Using these novel anti-IDE mAbs, we also developed sensitive and quantitative sandwich ELISAs capable of quantifying IDE levels present in human brain extracts. Conclusion We succeeded in developing novel mAbs that selectively detect rodent and/or human IDE, which we have shown to be suitable for a wide range of applications, including western blotting, immunoprecipitation, immunocytochemistry, immunohistochemistry, and quantitative sandwich ELISAs. These novel anti-IDE mAbs and the assays derived from them constitute important new tools for addressing many unresolved questions about the basic biology of IDE and its role in multiple highly prevalent human diseases.

  13. Elisa Studio showroom = Elisa Studio showroom / Jan Joonas Graps ; kommenteerinud Tiina Kuusisto

    Index Scriptorium Estoniae

    Graps, Jan Joonas, 1972-

    2015-01-01

    Elisa Studio showroom Helsingis Lasiplatsi, Mannerheimintie 22-24. Sisekujunduse autorid Jan Joonas Graps, Ken-Kristjan Ruut, Anne Määrmann (JanKen Wisespace). Lühidalt loovstuudiost JanKen Wisespace

  14. Elisa Studio showroom = Elisa Studio showroom / Jan Joonas Graps ; kommenteerinud Tiina Kuusisto

    Index Scriptorium Estoniae

    Graps, Jan Joonas, 1972-

    2015-01-01

    Elisa Studio showroom Helsingis Lasiplatsi, Mannerheimintie 22-24. Sisekujunduse autorid Jan Joonas Graps, Ken-Kristjan Ruut, Anne Määrmann (JanKen Wisespace). Lühidalt loovstuudiost JanKen Wisespace

  15. Graphene-sandwiched silicon structures for greatly enhanced unpolarized light absorption

    Science.gov (United States)

    Shi, Kaifeng; Haque, Riaz R.; Mao, Ling-Feng; Lu, Zhaolin

    2015-03-01

    Based on the attenuated total reflection configuration, a multi-layer graphene (MLG) sandwiched silicon structure is proposed for greatly enhancing light absorption over a broad spectral range (1000-2000 nm). At specific incident angles, the electric field in the sandwiched graphene can be simultaneously enhanced for both transverse electric (TE) and transverse magnetic (TM) polarized light. Numerical analysis and finite-difference time-domain simulation demonstrate over 80% and 70% light absorption for TE- and TM-polarized light, respectively. Owing to the unique optical properties of graphene, the absorption of any photon by graphene may give rise to an electron-hole pair. Thus, the greatly enhanced absorption of unpolarized, broadband light may find significant applications in future photovoltaic devices. However, the excess energy carried by the electron-hole pair can dissipate within a sub-picosecond due to the ultra-fast intraband carrier relaxation, which is the challenge for photovoltaic application and will also be discussed.

  16. Multilayered sandwich-like architecture containing large-scale faceted Al–Cu–Fe quasicrystal grains

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Dongxia; He, Zhanbing, E-mail: hezhanbing@ustb.edu.cn

    2016-01-15

    Faceted quasicrystals are structurally special compared with traditional crystals. Although the application of faceted quasicrystals has been expected, wide-scale application has not occurred owing to the limited exposure of the facets. Using a facile method of heat treatment, we synthesize a multilayered sandwich-like structure with each layer composed of large-scale pentagonal-dodecahedra of Al–Cu–Fe quasicrystals. Moreover, there are channels between the adjacent Al–Cu–Fe layers that serve to increase the exposure of the facets of quasicrystals. Scanning electron microscopy, transmission electron microscopy, and X-ray diffraction are used to characterize the multilayered architecture, and the generation mechanisms of this special structure are also discussed. - Highlights: • A multilayered sandwich-like structure is produced by a facile method. • Each layer is covered by large-scale faceted Al–Cu–Fe quasicrystals. • There are channels between the adjacent Al–Cu–Fe layers.

  17. The feasibility of harmonizing gluten ELISA measurements.

    Science.gov (United States)

    Rzychon, Malgorzata; Brohée, Marcel; Cordeiro, Fernando; Haraszi, Reka; Ulberth, Franz; O'Connor, Gavin

    2017-11-01

    Many publications have highlighted that routine ELISA methods do not give rise to equivalent gluten content measurement results. In this study, we assess this variation between results and its likely impact on the enforcement of the EU gluten-free legislation. This study systematically examines the feasibility of harmonizing gluten ELISA assays by the introduction of: a common extraction procedure; a common calibrator, such as a pure gluten extract and an incurred matrix material. The comparability of measurements is limited by a weak correlation between kit results caused by differences in the selectivity of the methods. This lack of correlation produces bias that cannot be corrected by using reference materials alone. The use of a common calibrator reduced the between-assay variability to some extent, but variation due to differences in selectivity of the assays was unaffected. Consensus on robust markers and their conversion to "gluten content" are required. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Thermal conductivity of newspaper sandwiched aerated lightweight concrete panel

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Soon-Ching; Low, Kaw-Sai [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Wilayah Persekutuan (Malaysia)

    2010-12-15

    Investigation on the thermal conductivity of newspaper sandwiched aerated lightweight concrete (ALC) panels is the main purpose of this study. Various densities of ALC panels ranging from 1700, 1400 and 1100 kg/m{sup 3} with three different aerial intensities of newspaper sandwiched were produced. Investigation was limited to the effect of aerial intensity of newspaper sandwiched and the effect of density of ALC on thermal conductivity. It is found that the thermal conductivity of newspaper sandwiched ALC panels reduced remarkably compared to control ALC panels. The reduction was recorded at 18.0%, 21.8% and 20.7% correspond to densities of 1700, 1400 and 1100 kg/m{sup 3} with just a mere 0.05 g/cm{sup 2} aerial intensity of newspaper sandwiched. Newspaper sandwiched has a significant impact on the performance of thermal conductivity of ALC panels based on regression analysis. (author)

  19. Sandwich-like singled-walled titania nanotube as a novel semiconductor electrode for quantum dot-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Cunku; Li, Xin; Fan, Xiujuan [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Qi, Jingyao [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2012-06-15

    A novel sandwich-like singled-walled titania nanotube is designed as a photoanode in quantum dot-sensitized solar cells. It acts as a hollow coaxial nanocable, in which the injected electron is confined in the conducting layer for transport, guarded from electron recombination by the protective layers. An ultrafast interfacial electron transfer is also expected in this photoelectric system due to the unique nanoarchitecture. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. A colorimetric sandwich-type assay for sensitive thrombin detection based on enzyme-linked aptamer assay.

    Science.gov (United States)

    Park, Jun Hee; Cho, Yea Seul; Kang, Sungmuk; Lee, Eun Jeong; Lee, Gwan-Ho; Hah, Sang Soo

    2014-10-01

    A colorimetric sandwich-type assay based on enzyme-linked aptamer assay has been developed for the fast and sensitive detection of as low as 25 fM of thrombin with high linearity. Aptamer-immobilized glass was used to capture the target analyte, whereas a second aptamer, functionalized with horseradish peroxidase (HRP), was employed for the conventional 3,5,3',5'-tetramethylbenzidine (TMB)-based colorimetric detection. Without the troublesome antibody requirement of the conventional enzyme-linked immunosorbent assay (ELISA), as low as 25 fM of thrombin could be rapidly and reproducibly detected. This assay has superior, or at least equal, recovery and accuracy to that of conventional antibody-based ELISA.

  1. Development of a new hazelnut sandwich ELISA based on detection of Cor a 9, a major hazelnut allergen

    OpenAIRE

    Trashin, Stanislav; Cucu, Tatiana; Devreese, Bart; De Meulenaer, Bruno

    2010-01-01

    The emerging health problem of food-induced allergic reactions, including life-threatening anaphylaxis, presents an important challenge to the food. In the framework of the current ALLERRISK project, analytical approaches for allergen detection are evaluated and developed. Cor a 9 is a major hazelnut protein with nutrient reservoir function, and that also known as a major food allergen. Presence of Cor a 9 indicates contamination of a product with hazelnut and, consequently, potential risk of...

  2. Dynamics of glucagon secretion in mice and rats revealed using a validated sandwich ELISA for small sample volumes

    DEFF Research Database (Denmark)

    Albrechtsen, Nicolai Jacob Wewer; Kuhre, Rune Ehrenreich; Windeløv, Johanne Agerlin

    2016-01-01

    secretion in response to intravenous glucose and arginine in anesthetized mice (isoflurane) and rats (Hypnorm/midazolam). Glucose caused a long-lasting suppression to very low values (1–2 pmol/l) within 2 min in both species. Arginine stimulated secretion 8- to 10-fold in both species, peaking at 1–2 min...

  3. Design Analysis of the Mixed Mode Bending Sandwich Specimen

    DEFF Research Database (Denmark)

    Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    A design analysis of the mixed mode bending (MMB) sandwich specimen for face–core interface fracture characterization is presented. An analysis of the competing failure modes in the foam cored sandwich specimens is performed in order to achieve face–core debond fracture prior to other failure modes....... The analysis facilitates selection of the appropriate geometry for the MMB sandwich specimen to promote debond failure. An experimental study is performed using MMB sandwich specimens with a H100 PVC foam core and E-glass–polyester faces. The results reveal that debond propagation is successfully achieved...... for the chosen geometries and mixed mode loading conditions....

  4. Influence of plywood grain direction on sandwich panel bending properties

    OpenAIRE

    Jaroslav Kljak; Mladen Brezović; Alan Antonović

    2009-01-01

    This paper investigates the influence of plywood grain direction on bending properties of a sandwich panel, as well as on stress distribution in each layer. Experimental sandwich panels (tnom= 29 mm) were made of two three-ply plywood panels and a rigid PVC core between them. Grain directions of plywood panels were between 0° and 90°, continuously raised by 15°. Seven models of sandwich panels were made. Bending properties of a sandwich panel was determined by three point bending method and s...

  5. Buckling Analysis of Debonded Sandwich Panel Under Compression

    Science.gov (United States)

    Sleight, David W.; Wang, John T.

    1995-01-01

    A sandwich panel with initial through-the-width debonds is analyzed to study the buckling of its faceskin when subject to an in-plane compressive load. The debonded faceskin is modeled as a beam on a Winkler elastic foundation in which the springs of the elastic foundation represent the sandwich foam. The Rayleigh-Ritz and finite-difference methods are used to predict the critical buckling load for various debond lengths and stiffnesses of the sandwich foam. The accuracy of the methods is assessed with a plane-strain finite-element analysis. Results indicate that the elastic foundation approach underpredicts buckling loads for sandwich panels with isotropic foam cores.

  6. Analytical determination of the ultimate strength of sandwich beams

    Science.gov (United States)

    Theotokoglou, Efstathios E.

    1996-09-01

    An analytical determination of the ultimate strength of a typical GRP/PVC sandwich beam has been performed. These beams represent common building practise in marine applications. Equations describing the behaviour of a sandwich panel under beam loading and various failure modes have been developed. The method has been applied to predict the ultimate load for a simple supported sandwich beam. The critical loads have been compared with those from the experimental investigation of a typical bulkhead-to-hull GRP/PVC sandwich T-joint under pull out forces.

  7. Elastic constants for superplastically formed/diffusion-bonded sandwich structures

    Science.gov (United States)

    Ko, W. L.

    1979-01-01

    Formulae and the associated graphs are presented for contrasting the effective elastic constants for a superplastically formed/diffusion-bonded (SPF/DB) corrugated sandwich core and a honeycomb sandwich core. The results used in the comparison of the structural properties of the two types of sandwich cores are under conditions of equal sandwich density. It was found that the stiffness in the thickness direction of the optimum SPF/DB corrugated core (i.e., triangular truss core) was lower than that of the honeycomb core, and that the former had higher transverse shear stiffness than the latter.

  8. Development of ELISA for the detection of transgenic vegetative insecticidal protein in GM crops/produce.

    Science.gov (United States)

    Kumar, R

    2012-01-11

    In the process of the development of insect-resistant genetically modified (GM) crops and also to evaluate the consistency in the expression of toxin under field conditions, immunological assays are commonly being used. An immunoassay was developed to support the labelling of vegetative insecticidal protein (Vip3A)-based GM produce. The developed ELISA for the measurement of Vip3A is a triple antibody sandwich procedure utilising a polyclonal capture antibody (mouse anti-Vip3A) and a polyclonal detection antibody (rabbit anti-Vip3A) followed by use of a third HRP-conjugated anti-species antibody (goat anti-rabbit IgG). The limit of detection limit of the ELISA assay was 16 ng ml(-1) with a linear quantification range from approximately 31 to 500 ng ml(-1) of Vip3A protein. Furthermore, the assay was in-house validated with GM brinjal samples. The assay was specific, sensitive and reproducible, which can be helpful to detect and track down the spread of unapproved and intentionally/unintentionally released GM produce harbouring Vip protein.

  9. Characterisation and quantitation of pilus antigens of Moraxella bovis by ELISA.

    Science.gov (United States)

    Lepper, A W; Hermans, L R

    1986-12-01

    Hyperimmune serums raised in rabbits to purified pili from 9 Australian and 2 American strains of Moraxella bovis from infectious bovine keratoconjunctivitis (IBK) affected herds were used to study the degree of binding between combinations of antigen and antiserum in a conventional enzyme linked immunosorbent assay (ELISA). With the aid of appropriate absorption tests major antigenic differences among pili were found permitting 6 distinct serogroups to be recognised. Further, production of specific antiserums to representative strains of each serogroup in goats facilitated the development of a double antibody sandwich ELISA which could be used to quantitate pilus expression of a given strain of M. bovis, or to differentiate pilus serogroups of 22 strains of M. bovis obtained from a total of 12 Australian herds. Most isolates were found to belong to serogroups designated IV and V. One strain from the United States of America showed total homology with Australian serogroup IV while the other showed some cross-reactivity with serogroups V and VI.

  10. On curves on sandwiched surface singularities

    OpenAIRE

    Fernandez-Sanchez, Jesus

    2007-01-01

    Fixed a point O on a non-singular surface S and a complete mO-primary ideal I in its local ring, the curves on the surface X obtained by blowing-up I are studied in terms of the base points of I. Criteria for the principality of these curves are obtained. New formulas for their multiplicity, intersection numbers and order of singularity at the singularities of X are given. The semigroup of branches going through a sandwiched singularity is effectively determined, too.

  11. Failure modes of composite sandwich beams

    Directory of Open Access Journals (Sweden)

    Gdoutos E.

    2008-01-01

    Full Text Available A thorough investigation of failure behavior of composite sandwich beams under three-and four-point bending was undertaken. The beams were made of unidirectional carbon/epoxy facings and a PVC closed-cell foam core. The constituent materials were fully characterized and in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Various failure modes including facing wrinkling, indentation failure and core failure were observed and compared with analytical predictions. The initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical dimensions.

  12. Recent trends in aluminum foam sandwich technology

    Energy Technology Data Exchange (ETDEWEB)

    Banhart, John [TU Berlin, Materials Science and Technology, Hardenbergstr. 36, 10623 Berlin (Germany); Helmholtz-Centre Berlin, Hahn-Meitner-Platz, 14109 Berlin (Germany); Seeliger, Hans-Wolfgang [Pohltec Metalfoam GmbH, Robert-Bosch-Str. 6D, 50769 Koeln (Germany)

    2012-12-15

    We review the status of aluminum foam sandwich (AFS) technology and discuss both recent improvements of foaming technology and current application strategies. It is concluded that the quality of foams has improved in the past years but the costs are still very much the same. This is why applications in which metal foams have more than one function are more likely to be economically viable. The examples presented include electromagnetic shielding, carrier plates for mirrors, cooking equipment, architectural panels, and blast protection. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. The magnetic and quantum transport properties of benzene-vanadium-borazine mixed sandwich clusters: a new kind of spin filter.

    Science.gov (United States)

    Yang, Zhi; Liu, Shaoding; Liu, Xuguang; Yang, Yongzhen; Li, Xiuyan; Xiong, Shijie; Xu, Bingshe

    2012-11-07

    Using density functional theory and the non-equilibrium Green's function technique, we performed theoretical investigations on the magnetic and quantum transport properties of benzene-vanadium-borazine mixed organic/inorganic ligand sandwich clusters. The calculated results show that these finite sandwich clusters coupled to Ni electrodes exhibit novel quantum transport properties such as half-metallicity, negative differential resistance and spin-reversal effect, and can be viewed as a new kind of spin filter. However, for the infinite molecular wire, the ground state was identified as a ferromagnetic semiconductor with high stability. These findings suggest that the mixed organic/inorganic ligand sandwich clusters and molecular wires are promising materials for application in molecular electronics and spintronics.

  14. Sero-epidemiology of Breda virus in cattle using ELISA

    NARCIS (Netherlands)

    Horzinek, M.C.; Koopmans, M.P.; Boom, U. van den; Woode, G.N.

    1989-01-01

    Two direct blocking enzyme linked immunosorbent assays (ELISA) for the detection of antibodies to Breda virus in sera of cattle were compared. An ELISA with consecutive addition of antigen and test serum to an antibody-coated plate gave higher positive: negative absorbence ratios than an ELISA in wh

  15. Comparison of Laboratory-Developed and Commercial Monoclonal Antibody-Based Sandwich Enzyme-Linked Immunosorbent Assays for Almond (Prunus dulcis) Detection and Quantification.

    Science.gov (United States)

    Liu, Changqi; Chhabra, Guneet S; Zhao, Jing; Zaffran, Valerie D; Gupta, Sahil; Roux, Kenneth H; Gradziel, Thomas M; Sathe, Shridhar K

    2017-09-04

    A commercially available monoclonal antibody (mAb)-based direct sandwich enzyme-linked immunosorbent assay (ELISA) kit (BioFront Technologies, Tallahassee, Fla., U.S.A.) was compared with an in-house developed mAb 4C10-based ELISA for almond detection. The assays were comparable in sensitivity (limit of detection < 1 ppm full fat almond, limit of quantification < 5 ppm full fat almond), specificity (no cross-reactivity with 156 tested foods at a concentration of 100000 ppm whole sample), and reproducibility (intra- and interassay variability < 15% CV). The target antigens were stable and detectable in whole almond seeds subjected to autoclaving, blanching, frying, microwaving, and dry roasting. The almond recovery ranges for spiked food matrices were 84.3% to 124.6% for 4C10 ELISA and 81.2% to 127.4% for MonoTrace ELISA. The almond recovery ranges for commercial and laboratory prepared foods with declared/known almond amount were 30.9% to 161.2% for 4C10 ELISA and 38.1% to 207.6% for MonoTrace ELISA. Neither assay registered any false-positive or negative results among the tested commercial and laboratory prepared samples. © 2017 Institute of Food Technologists®.

  16. Remanent resistance changes in metal- PrCaMnO-metal sandwich structures

    Energy Technology Data Exchange (ETDEWEB)

    Scherff, Malte; Meyer, Bjoern-Uwe; Scholz, Julius; Hoffmann, Joerg; Jooss, Christian [Institute of Materials Physics, University of Goettingen (Germany)

    2012-07-01

    The non-volatile electric pulse induced resistance change (EPIR) seems to be a rather common feature of oxides sandwiched by electrodes. However, microscopic mechanisms are discussed controversially. We present electrical transport measurements of sputtered Pr{sub 0.7}Ca{sub 0.3}MnO{sub 3} films sandwiched by metallic electrodes with variation of electrode materials, device geometry and PCMO deposition parameters. Cross-plane transport measurements have been performed as function of temperature and magnetic field. Specifically, the transition from dynamic resistance changes due to non-linear transport to remanent switching is analyzed. By analyzing changes of magneto-resistance at low temperatures in different resistance states we aim for separation between interface and film contributions to switching. Comparing switching behavior in symmetric and asymmetric electrode configuration allows for identification of the active, single interface in the switching process and the origin of an observed switching polarity inversion. The influence of excitation field and power on the switching characteristics of different noble metal electrodes is discussed. Samples from macroscopic devices and in situ stimulated sandwich structures were studied in a transmission electron microscope in order to investigate the induced structural, chemical and electronic changes.

  17. Dynamic Failure of Composite and Sandwich Structures

    CERN Document Server

    Abrate, Serge; Rajapakse, Yapa D S

    2013-01-01

    This book presents a broad view of the current state of the art regarding the dynamic response of composite and sandwich structures subjected to impacts and explosions. Each chapter combines a thorough assessment of the literature with original contributions made by the authors.  The first section deals with fluid-structure interactions in marine structures.  The first chapter focuses on hull slamming and particularly cases in which the deformation of the structure affects the motion of the fluid during the water entry of flexible hulls. Chapter 2 presents an extensive series of tests underwater and in the air to determine the effects of explosions on composite and sandwich structures.  Full-scale structures were subjected to significant explosive charges, and such results are extremely rare in the open literature.  Chapter 3 describes a simple geometrical theory of diffraction for describing the interaction of an underwater blast wave with submerged structures. The second section addresses the problem of...

  18. Sandwich materials for wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Thybo Thomsen, O. [Aalborg Univ., Dept. of Mechanical Engineering, Aalborg (Denmark)

    2006-07-01

    Wind turbine blades are being manufactured using polymer matrix composite materials (PMC), in a combination of monolithic (single skin) and sandwich composites. Present day designs are mainly based on glass fibre reinforced composites (GFRP), but for very large blades carbon fibre reinforced composites (CFRP) are being used increasingly, in addition to GFRP by several manufacturers to reduce the weight. The size of wind turbines have increased significantly over the last 25 years, and this trend is expected to continue in the future. Thus, it is anticipated that wind turbines with a rated power output in the range of 8-10 MW and a rotor diameter about 170-180 m will be developed and installed within the next 10-15 years. The paper presents an overview of current day design principles and materials technology applied for wind turbine blades, and it highlights the limitations and important design issues to be addressed for up-scaling of wind turbine blades from the current maximum length in excess of 61 m to blade lengths in the vicinity of 90 m as envisaged for future very large wind turbines. In particular, the paper discusses the potential advantages and challenges of applying sandwich type construction to a larger extent than is currently being practiced for the load carrying parts of wind turbine blades. (au)

  19. Quantum radiation from a sandwich black hole

    Science.gov (United States)

    Frolov, Valeri P.; Zelnikov, Andrei

    2017-02-01

    We discuss quantum radiation of a massless scalar field from a spherically symmetric nonsingular black hole with a finite lifetime. Namely, we discuss a sandwich black-hole model, where a black hole is originally created by a collapse of a null shell of mass M , and later, after some time Δ V , it is disrupted by the collapse of the other shell with negative mass -M . We assume that between the shells the metric is static and either coincides with the Hayward metric or with a special generalization of it. We show that in both cases for a sufficiently large parameter Δ V the radiation after the formation of the black hole practically coincides with the Hawking result. We also calculate the radiation, emitted from the black hole interior. This radiation contains a peak at the moment when the second shell intersects the inner horizon. In the standard sandwich metric (with the Hayward interior) this outburst of energy is exponentially large. In the modified metric, which includes an additional nontrivial redshift parameter, this exponent is suppressed. This is a result of a significant decrease of the surface gravity of the inner horizon in the latter case. We discuss possible consequences of this result in the context of the self-consistency requirement for nonsingular models with quantum radiation.

  20. Fracture Analysis of Debonded Sandwich Columns Under Axial Compression

    DEFF Research Database (Denmark)

    May, A.; Avilés, F.; Berggreen, Christian

    A sandwich structure consists of two strong and stiff face sheets bonded to a weak low density core. The large separation between the face sheets provides increased bending rigidity and strength at low weight cost. Thus, sandwich structures frequently present better mechanical properties than mon...

  1. Practical Instruction in Tissue Culture and Cytogenetics for Sandwich Students.

    Science.gov (United States)

    Williams, D. C.; Bishun, N. P.

    1973-01-01

    Describes the training and practical techniques taught to students involved in a sandwich course at the Tissue Culture and Cytogenetics Unit of the Marie Curie Memorial Foundation, Surrey, England. Students spend a minimum of six months involved in the sandwich course before returning to university for a final academic year. (JR)

  2. Query processing of pre-partitioned data using Sandwich Operators

    NARCIS (Netherlands)

    Baumann, S.; Boncz, P.A.; Sattler, K.-U.

    2012-01-01

    In this paper we present the Sandwich Operators, an elegant approach to exploit pre-sorting or pre-grouping from clustered storage schemes in operators such as Aggregation/Grouping, HashJoin, and Sort of a database management system. Thereby, each of these operator types is "sandwiched" by two new o

  3. Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    Various modifications of the face/core interface in foam core sandwich specimens are examined in a series of two papers. This paper constitutes part I and describes the finite element analysis of a sandwich test specimen, i.e. a DCB specimen loaded by uneven bending moments (DCB-UBM). Using...

  4. Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    A face/core debond in a sandwich structure may propagate in the interface or kink into either the face or core. It is found that certain modifications of the face/core interface region influence the kinking behavior, which is studied experimentally in the present paper. A sandwich double cantilever...

  5. Fracture Analysis of Debonded Sandwich Columns Under Axial Compression

    DEFF Research Database (Denmark)

    May, A.; Avilés, F.; Berggreen, Christian

    A sandwich structure consists of two strong and stiff face sheets bonded to a weak low density core. The large separation between the face sheets provides increased bending rigidity and strength at low weight cost. Thus, sandwich structures frequently present better mechanical properties than mon...

  6. Thick Plate Homogenization of Sandwich Panels Including Folded Cellular Cores

    OpenAIRE

    LEBEE, Arthur; Sab, Karam

    2011-01-01

    In the present work, we provide the Bending-Gradient homogenization scheme and apply it to a sandwich panel including the chevron pattern. It turns out that the shear forces stiffness of the sandwich panel is strongly influenced by a skin distortion phenomenon which cannot be neglected in conventional design.

  7. Finite Element Modeling of the Buckling Response of Sandwich Panels

    Science.gov (United States)

    Rose, Cheryl A.; Moore, David F.; Knight, Norman F., Jr.; Rankin, Charles C.

    2002-01-01

    A comparative study of different modeling approaches for predicting sandwich panel buckling response is described. The study considers sandwich panels with anisotropic face sheets and a very thick core. Results from conventional analytical solutions for sandwich panel overall buckling and face-sheet-wrinkling type modes are compared with solutions obtained using different finite element modeling approaches. Finite element solutions are obtained using layered shell element models, with and without transverse shear flexibility, layered shell/solid element models, with shell elements for the face sheets and solid elements for the core, and sandwich models using a recently developed specialty sandwich element. Convergence characteristics of the shell/solid and sandwich element modeling approaches with respect to in-plane and through-the-thickness discretization, are demonstrated. Results of the study indicate that the specialty sandwich element provides an accurate and effective modeling approach for predicting both overall and localized sandwich panel buckling response. Furthermore, results indicate that anisotropy of the face sheets, along with the ratio of principle elastic moduli, affect the buckling response and these effects may not be represented accurately by analytical solutions. Modeling recommendations are also provided.

  8. Optimization of sandwich composites fuselages under flight loads

    NARCIS (Netherlands)

    Yan, C.; Bergsma, O.; Koussios, S.; Zu, L.; Beukers, A.

    2010-01-01

    The sandwich composites fuselages appear to be a promising choice for the future aircrafts because of their structural efficiency and functional integration advantages. However, the design of sandwich composites is more complex than other structures because of many involved variables. In this paper,

  9. Design and manufacturing of bio-based sandwich structures

    CSIR Research Space (South Africa)

    John, Maya J

    2017-03-01

    Full Text Available The aim of this chapter is to discuss the design and manufacturing of bio-based sandwich structures. As the economic advantages of weight reduction have become mandatory for many advanced industries, bio-based sandwich panels have emerged...

  10. Design, fabrication and test of liquid metal heat-pipe sandwich panels

    Science.gov (United States)

    Basiulis, A.; Camarda, C. J.

    1983-01-01

    Integral heat-pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich panel construction, were fabricated and tested. The designs utilize two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and potassium or sodium as the working fluid. Panels were tested by radiant heating, and the results indicate successful heat pipe operation at temperatures of approximately 922K (1200F). These panels, in addition to solving potential thermal stress problems in an Airframe-Integrated Scramjet Engine, have potential applications as cold plates for electronic component cooling, as radiators for space platforms, and as low distortion, large area structures.

  11. Detection of canine echinococcosis by coproantigen ELISA

    Institute of Scientific and Technical Information of China (English)

    DeS; PanD; BeraAK; SreevatsavaV; DasSK; DasS; RanaT; BandyopadhyayS; BhattacharyaD

    2010-01-01

    Objective:To study the canine echinococcosis by coproantigen ELISA method. Methods:During the present investigation experimental infection was established using evaginated worms of Echinococcus granulosus (E. granulosus). To check cross reactivity two pups were infected with Taenia hydatigena(T. hydatigena). In order to detect the presence of antigen, hyperimmune sera were raised against excretory-secretory products of adult worms E. chinococcus granulosus. Faecal sample collected either from experimentally infected pups or from other sources were heated at 70℃to detect heat stable soluble antigen. Results:Pups harbouring less than 104 worms showed negative results. Samples collected from 14 days onwards from experimentally infected animals harbouring more than 104 worms showed positive value. The maximum positive samples were detected in samples collected from in and around slaughter house and the least number of samples were detected positive maintained by dog squad. Conclusions:The affinity purified IgG exhibited promising results for detection of canine echinococcosis by indirect ELISA.

  12. Development, testing, and numerical modeling of a foam sandwich biocomposite

    Science.gov (United States)

    Chachra, Ricky

    This study develops a novel sandwich composite material using plant based materials for potential use in nonstructural building applications. The face sheets comprise woven hemp fabric and a sap based epoxy, while the core comprises castor oil based foam with waste rice hulls as reinforcement. Mechanical properties of the individual materials are tested in uniaxial compression and tension for the foam and hemp, respectively. The sandwich composite is tested in 3 point bending. Flexural results are compared to a finite element model developed in the commercial software Abaqus, and the validated model is then used to investigate alternate sandwich geometries. Sandwich model responses are compared to existing standards for nonstructural building panels, showing that the novel material is roughly half the strength of equally thick drywall. When space limitations are not an issue, a double thickness sandwich biocomposite is found to be a structurally acceptable replacement for standard gypsum drywall.

  13. Sandwich module prototype progress for space solar power

    Science.gov (United States)

    Jaffe, Paul; Hodkin, Jason; Harrington, Forest; Person, Clark; Nurnberger, Michael; Nguyen, Bang; LaCava, Susie; Scheiman, Dave; Stewart, Grant; Han, Andrew; Hettwer, Ethan; Rhoades, Daniel

    2014-02-01

    Space solar power (SSP) has been broadly defined as the collection of solar energy in space and its wireless transmission for use on earth. This approach potentially gives the benefit of provision of baseload power while avoiding the losses due to the day/night cycle and tropospheric effects that are associated with terrestrial solar power. Proponents have contended that the implementation of such systems could offer energy security, environmental, and technological advantages to those who would undertake their development. Among recent implementations commonly proposed for SSP, the modular symmetrical concentrator (MSC) and other modular concepts have received considerable attention. Each employs an array of modules for performing conversion of concentrated sunlight into microwaves or laser beams for transmission to earth. While prototypes of such modules have been designed and developed previously by several groups, none have been subjected to the challenging conditions inherent to the space environment and the possible solar concentration levels in which an array of modules might be required to operate. The research described herein details our team's efforts in the development of photovoltaic arrays, power electronics, microwave conversion electronics, and antennas for microwave-based "sandwich" module prototypes. The implementation status and testing results of the prototypes are reviewed.

  14. Development of an Aquaporin-4 Orthogonal Array of Particle-Based ELISA for Neuromyelitis Optica Autoantibodies Detection.

    Directory of Open Access Journals (Sweden)

    Francesco Pisani

    Full Text Available Serological markers of Nuromyelitis Optica (NMO, an autoimmune disorder of the central nervous system, are autoantibodies targeting the astrocytic water channel aquaporin-4 (AQP4. We have previously demonstrated that the main epitopes for these autoantibodies (AQP4-IgG are generated by the supramolecular arrangement of AQP4 tetramers into an Orthogonal Array of Particles (OAPs. Many tests have been developed to detect AQP4-IgG in patient sera but several procedural issues affect OAP assembly and consequently test sensitivity. To date, the protein based ELISA test shows the lowest sensitivity while representing a valid alternative to the more sensitive cell based assay (CBA, which, however, shows economic, technical and interpretation problems. Here we have developed a high perfomance ELISA in which native OAPs are used as the molecular target. To this aim a native size exclusion chromatography method has been developed to isolate integral, highly pure and AQP4-IgG-recognized OAPs from rat brain. These OAPs were immobilized and oriented on a plastic plate by a sandwich approach and 139 human sera were tested, including 67 sera from NMO patients. The OAP-ELISA showed a 99% specificity and a higher sensitivity (91% compared to the CBA test. A comparative analysis revealed an end-point titer three orders of magnitude higher than the commercial ELISA and six times higher than our in-house CBA test. We show that CNS-extracted OAPs are crucial elements in order to perform an efficient AQP4-IgG test and the OAP-ELISA developed represents a valid alternative to the CBA currently used.

  15. Development of an Aquaporin-4 Orthogonal Array of Particle-Based ELISA for Neuromyelitis Optica Autoantibodies Detection.

    Science.gov (United States)

    Pisani, Francesco; Settanni, Paolo; Rosito, Stefania; Mola, Maria Grazia; Iorio, Raffaele; Tortorella, Carla; Ruggieri, Maddalena; Trojano, Maria; Svelto, Maria; Frigeri, Antonio; Nicchia, Grazia Paola

    2015-01-01

    Serological markers of Nuromyelitis Optica (NMO), an autoimmune disorder of the central nervous system, are autoantibodies targeting the astrocytic water channel aquaporin-4 (AQP4). We have previously demonstrated that the main epitopes for these autoantibodies (AQP4-IgG) are generated by the supramolecular arrangement of AQP4 tetramers into an Orthogonal Array of Particles (OAPs). Many tests have been developed to detect AQP4-IgG in patient sera but several procedural issues affect OAP assembly and consequently test sensitivity. To date, the protein based ELISA test shows the lowest sensitivity while representing a valid alternative to the more sensitive cell based assay (CBA), which, however, shows economic, technical and interpretation problems. Here we have developed a high perfomance ELISA in which native OAPs are used as the molecular target. To this aim a native size exclusion chromatography method has been developed to isolate integral, highly pure and AQP4-IgG-recognized OAPs from rat brain. These OAPs were immobilized and oriented on a plastic plate by a sandwich approach and 139 human sera were tested, including 67 sera from NMO patients. The OAP-ELISA showed a 99% specificity and a higher sensitivity (91%) compared to the CBA test. A comparative analysis revealed an end-point titer three orders of magnitude higher than the commercial ELISA and six times higher than our in-house CBA test. We show that CNS-extracted OAPs are crucial elements in order to perform an efficient AQP4-IgG test and the OAP-ELISA developed represents a valid alternative to the CBA currently used.

  16. Development of ELISA for diagnosis of allergy to Dermatophagoides farinae.

    Science.gov (United States)

    Ho, T M; Radha, K; Shahnaz, M; Singaram, S P

    1993-09-01

    An indirect enzyme linked immunosorbent assay (ELISA) was developed for the diagnosis of allergy to a house dust mite, Dermatophagoides farinae. The efficacy of the ELISA was then evaluated against a prick test using a commercial allergen. Eighty five suspected allergic rhinitis patients from the Otorhinolaryngology Department, Kuala Lumpur General Hospital, were tested with the ELISA and prick test. Prick test and ELISA results were positive in 84.7% and 80.0% of the patients respectively. The ELISA was found to have 87.5% sensitivity, 61.5% specificity, 92.6% positive predictive value, 47.1% negative predictive value, 7.4% false positive and 52.9% false negative. There was total agreement between the prick test and ELISA for prick test grades of 3+ and 4+. It is concluded that the ELISA is a useful assay for detection of individuals who are highly sensitive to D. farinae.

  17. DNA-based hybridization chain reaction and biotin-streptavidin signal amplification for sensitive detection of Escherichia coli O157:H7 through ELISA.

    Science.gov (United States)

    Guo, Qi; Han, Jiao-Jiao; Shan, Shan; Liu, Dao-Feng; Wu, Song-Song; Xiong, Yong-Hua; Lai, Wei-Hua

    2016-12-15

    This study reported on a novel sandwich enzyme linked immunosorbent assay (ELISA) for the sensitive determination of Escherichia coli O157:H7 (E. coli O157:H7) by using DNA-based hybridization chain reaction (HCR) and biotin-streptavidin signal amplification. The anti-E. coli O157:H7 polyclonal antibody (pAb) was immobilized in the ELISA wells. The anti-E. coli O157:H7 monoclonal antibody (mAb) and initiator strand (DNA1) were labeled on gold nanoparticle (AuNP) to form a mAb-AuNP-DNA1 complex. In the presence of the target E. coli O157:H7, the sandwiched immunocomplex, which is pAb-E. coli O157:H7-mAb-AuNP-DNA1, could be formed. Two types of biotinylated hairpin were subsequently added in the ELISA well. A nicked double-stranded DNA (dsDNA) that contained abundant biotins was formed after HCR. Detection was performed after adding horseradish peroxidase-streptavidin and substrate/chromogen solution. Under optimal conditions, E. coli O157:H7 could be detected in the range of 5×10(2) CFU/mL to 1×10(7) CFU/mL; the limit of detection was 1.08×10(2) CFU/mL in pure culture. The LOD of the novel ELISA was 185 times lower than that of traditional ELISA. The proposed method is considerably specific and can be applied in the detection of whole milk samples inoculated with E. coli O157:H7. The coefficient of variation of in pure culture and in whole milk was 0.99-5.88% and 0.76-5.38%, respectively. This method offers a promising application in the detection of low concentrations of food-borne pathogens.

  18. Exploiting Nanobodies in the Detection and Quantification of Human Growth Hormone via Phage-Sandwich Enzyme-Linked Immunosorbent Assay

    Directory of Open Access Journals (Sweden)

    Hossam Murad

    2017-05-01

    Full Text Available BackgroundMonitoring blood levels of human growth hormone (hGH in most children with short stature deficiencies is crucial for taking a decision of treatment with extended course of daily and expensive doses of recombinant hGH (rhGH or Somatropin®. Besides, misusing of rhGH by sportsmen is banned by the World Anti-Doping Agency and thus sensitive GH-detecting methods are highly welcome in this field. Nanobodies are the tiniest antigen-binding entity derived from camel heavy chain antibodies. They were successfully generated against numerous antigens including hormones.MethodsA fully nanobody-based sandwich ELISA method was developed in this work for direct measurement of GH in biological samples.ResultsTwo major characteristics of nanobody were exploited for this goal: the robust and stable structure of the nanobody (NbGH04 used to capture hGH from tested samples, and the great ability of tailoring, enabling the display of the anti-GH detector nanobody (NbGH07 on the tip of M13-phage. Such huge, stable, and easy-to-prepare phage-Nb was used in ELISA to provide an amplified signal. Previously, NbGH04 was retrieved on immobilized hGH by phage display from a wide “immune” cDNA library prepared from a hGH-immunized camel. Here, and in order to assure epitope heterogeneity, NbGH07 was isolated from the same library using NbGH04-captured hGH as bait. Interaction of both nanobodies with hGH was characterized and compared with different anti-GH nanobodies and antibodies. The sensitivity (~0.5 ng/ml and stability of the nanobody-base sandwich ELISA were assessed using rhGH before testing in the quantification of hGH in blood sera and cell culture supernatants.ConclusionIn regard to all advantages of nanobodies; stability, solubility, production affordability in Escherichia coli, and gene tailoring, nanobody-based phage sandwich ELISA developed here would provide a valuable method for hGH detection and quantification.

  19. Exploiting Nanobodies in the Detection and Quantification of Human Growth Hormone via Phage-Sandwich Enzyme-Linked Immunosorbent Assay.

    Science.gov (United States)

    Murad, Hossam; Assaad, Jana Mir; Al-Shemali, Rasha; Abbady, Abdul Qader

    2017-01-01

    Monitoring blood levels of human growth hormone (hGH) in most children with short stature deficiencies is crucial for taking a decision of treatment with extended course of daily and expensive doses of recombinant hGH (rhGH or Somatropin(®)). Besides, misusing of rhGH by sportsmen is banned by the World Anti-Doping Agency and thus sensitive GH-detecting methods are highly welcome in this field. Nanobodies are the tiniest antigen-binding entity derived from camel heavy chain antibodies. They were successfully generated against numerous antigens including hormones. A fully nanobody-based sandwich ELISA method was developed in this work for direct measurement of GH in biological samples. Two major characteristics of nanobody were exploited for this goal: the robust and stable structure of the nanobody (NbGH04) used to capture hGH from tested samples, and the great ability of tailoring, enabling the display of the anti-GH detector nanobody (NbGH07) on the tip of M13-phage. Such huge, stable, and easy-to-prepare phage-Nb was used in ELISA to provide an amplified signal. Previously, NbGH04 was retrieved on immobilized hGH by phage display from a wide "immune" cDNA library prepared from a hGH-immunized camel. Here, and in order to assure epitope heterogeneity, NbGH07 was isolated from the same library using NbGH04-captured hGH as bait. Interaction of both nanobodies with hGH was characterized and compared with different anti-GH nanobodies and antibodies. The sensitivity (~0.5 ng/ml) and stability of the nanobody-base sandwich ELISA were assessed using rhGH before testing in the quantification of hGH in blood sera and cell culture supernatants. In regard to all advantages of nanobodies; stability, solubility, production affordability in Escherichia coli, and gene tailoring, nanobody-based phage sandwich ELISA developed here would provide a valuable method for hGH detection and quantification.

  20. Evaluation of a Commercial Sandwich Enzyme-Linked Immunosorbent Assay for the Quantification of Beta-Casomorphin 7 in Yogurt Using Solid-Phase Extraction Coupled to Liquid Chromatography-Tandem Mass Spectrometry as the "Gold Standard" Method.

    Science.gov (United States)

    Nguyen, Duc Doan; Busetti, Francesco; Johnson, Stuart Keith; Solah, Vicky Ann

    2017-08-01

    This study investigated beta-casomorphin 7 (BCM7) in yogurt by means of LC-tandem MS (MS/MS) and enzyme-linkedimmunosorbent assay (ELISA) and use LC-MS/MS as the "gold standard" method to evaluate the applicability of a commercial ELISA. The level of BCM7 in milk obtained from ELISA analysis was much lower than that obtained by LC-MS/MS analysis and trended to increase during fermentation and storage of yogurt. Meanwhile, the results obtained from LC-MS/MS showed that BCM7 degraded during stages of yogurt processing, and its degradation may have been caused by X-prolyl dipeptidyl aminopeptidase activity. As a result, the commercial sandwich ELISA kit was not suitable for the quantification of BCM7 in fermented dairy milk.

  1. A Sandwich HIV p24 Amperometric Immunosensor Based on a Direct Gold Electroplating-Modified Electrode

    Directory of Open Access Journals (Sweden)

    Ning Gan

    2012-05-01

    Full Text Available Acquired immune deficiency syndrome (AIDS is a severe communicable immune deficiency disease caused by the human immune deficiency virus (HIV. The analysis laboratory diagnosis of HIV infection is a crucial aspect of controlling AIDS. The p24 antigen, the HIV-1 capsid protein, is of considerable diagnostic interest because it is detectable several days earlier than host-generated HIV antibodies following HIV exposure. We present herein a new sandwich HIV p24 immunosensor based on directly electroplating an electrode surface with gold nanoparticles using chronoamperometry, which greatly increased the conductivity and reversibility of the electrode. Under optimum conditions, the electrochemical signal showed a linear relationship with the concentration of p24, ranging from 0.01 ng/mL to 100 ng/mL (R > 0.99, and the detection limit was 0.008 ng/mL. Compared with ELISA, this method increased the sensitivity by more than two orders of magnitude (the sensitivity of ELISA for p24 is about 1 ng/mL. This immunosensor may be broadly applied to clinical samples, being distinguished by its ease of use, mild reaction conditions, guaranteed reproducibility, and good anti-interference ability.

  2. Standard Test Method for Sandwich Corrosion Test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method defines the procedure for evaluating the corrosivity of aircraft maintenance chemicals, when present between faying surfaces (sandwich) of aluminum alloys commonly used for aircraft structures. This test method is intended to be used in the qualification and approval of compounds employed in aircraft maintenance operations. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information. 1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements appear in Section 9.

  3. Nanoparticle organization in sandwiched polymer brushes.

    Science.gov (United States)

    Curk, Tine; Martinez-Veracoechea, Francisco J; Frenkel, Daan; Dobnikar, Jure

    2014-05-14

    The organization of nanoparticles inside grafted polymer layers is governed by the interplay of polymer-induced entropic interactions and the action of externally applied fields. Earlier work had shown that strong external forces can drive the formation of colloidal structures in polymer brushes. Here we show that external fields are not essential to obtain such colloidal patterns: we report Monte Carlo and molecular dynamics simulations that demonstrate that ordered structures can be achieved by compressing a "sandwich" of two grafted polymer layers, or by squeezing a coated nanotube, with nanoparticles in between. We show that the pattern formation can be efficiently controlled by the applied pressure, while the characteristic length-scale, that is, the typical width of the patterns, is sensitive to the length of the polymers. Based on the results of the simulations, we derive an approximate equation of state for nanosandwiches.

  4. ELISA for complexes between urokinase-type plasminogen activator and its receptor in lung cancer tissue extracts

    DEFF Research Database (Denmark)

    de Witte, H; Pappot, H; Brünner, N;

    1997-01-01

    A sandwich-type ELISA has been developed for the assessment of complexes between urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in extracts of squamous cell lung carcinomas. The assay is based on a combination of rabbit polyclonal anti-uPA antibodies and a biotinylated mouse...... extraction of uPAR yields the highest amounts of uPA:uPAR complexes. Absorption of tumor extracts with anti-uPA or anti-uPAR MAbs results in a complete disappearance of the ELISA signal, demonstrating the specificity of the ELISA. The recovery of chemically cross-linked uPA:uPAR complexes added to tumor...... extracts varies between 80% and 105%. The intra- and inter-assay variation coefficients are 5.3% and 9.8%, respectively. Furthermore, a peptide antagonist for uPAR was employed to evaluate de novo uPA:uPAR complex formation during tumor tissue extraction and the immunoassay procedure. Our results strongly...

  5. eLISA and the Gravitational Universe

    Science.gov (United States)

    Danzmann, Karsten

    2015-08-01

    The last century has seen enormous progress in our understanding of the Universe. We know the life cycles of stars, the structure of galaxies, the remnants of the big bang, and have a general understanding of how the Universe evolved. We have come remarkably far using electromagnetic radiation as our tool for observing the Universe. However, gravity is the engine behind many of the processes in the Universe, and much of its action is dark. Opening a gravitational window on the Universe will let us go further than any alternative. Gravity has its own messenger: Gravitational waves, ripples in the fabric of spacetime. They travel essentially undisturbed and let us peer deep into the formation of the first seed black holes, exploring redshifts as large as z ~ 20, prior to the epoch of cosmic re-ionisation. Exquisite and unprecedented measurements of black hole masses and spins will make it possible to trace the history of black holes across all stages of galaxy evolution, and at the same time constrain any deviation from the Kerr metric of General Relativity. eLISA will be the first ever mission to study the entire Universe with gravitational waves. eLISA is an all-sky monitor and will offer a wide view of a dynamic cosmos using gravitational waves as new and unique messengers to unveil The Gravitational Universe. It provides the closest ever view of the early processes at TeV energies, has guaranteed sources in the form of verification binaries in the Milky Way, and can probe the entire Universe, from its smallest scales around singularities and black holes, all the way to cosmological dimensions.

  6. Development and Mechanical Behavior of FML/Aluminium Foam Sandwiches

    Science.gov (United States)

    Baştürk, S. B.; Tanoğlu, M.

    2013-10-01

    In this study, the Fiber-Metal Laminates (FMLs) containing glass fiber reinforced polypropylene (GFPP) and aluminum (Al) sheet were consolidated with Al foam cores for preparing the sandwich panels. The aim of this article is the comparison of the flexural properties of FML/Al foam sandwich panels bonded with various surface modification approaches (silane treatment and combination of silane treatment with polypropylene (PP) based film addition). The FML/foam sandwich systems were fabricated by laminating the components in a mould at 200 °C under 1.5 MPa pressure. The energy absorbtion capacities and flexural mechanical properties of the prepared sandwich systems were evaluated by mechanical tests. Experiments were performed on samples of varying foam thicknesses (8, 20 and 30 mm). The bonding among the sandwich components were achieved by various surface modification techniques. The Al sheet/Al foam sandwiches were also consolidated by bonding the components with an epoxy adhesive to reveal the effect of GFPP on the flexural performance of the sandwich structures.

  7. Marginal Adaptation Evaluation of Biodentine and MTA Plus in "Open Sandwich" Class II Restorations.

    Science.gov (United States)

    Aggarwal, Vivek; Singla, Mamta; Yadav, Suman; Yadav, Harish; Ragini

    2015-01-01

    This study aimed at evaluation of two different commercially available calcium silicate materials (Biodentine and mineral trioxide aggregate [MTA] Plus) used as dentin substitute. Sixty Class II cavities were prepared in extracted mandibular third molars, with margins extending 1 mm below the cementum-enamel junction. The samples were divided into three groups on the basis of dentin substitute used: resin modified glass ionomer cement, Biodentine, and MTA Plus. Cavities were restored with composite resins in an "open sandwich" technique. The samples were subjected to alternate aging in phosphate buffered saline and cyclic loading. Marginal adaptation was evaluated in terms of "continuous margin" at the gingival margin, using a low vacuum scanning electron microscope. Statistical analysis was done with two-way analysis of variance with Holm-Sidak's correction for multiple comparisons. The glass ionomer group and Biodentine group presented an overall 83% and 91% of continuous margins, with no difference between them. MTA Plus showed least values of continuous margins. Granular deposits were seen over the surface of Biodentine and MTA Plus. Biodentine and resin-modified glass ionomer cement, when used as a dentin substitute under composite restorations in open sandwich technique, gave satisfactory marginal adaptation values. Contemporary calcium silicate materials can be used as dentin substitute materials in "open sandwich" Class II restorations. This study evaluates the marginal adaptation of Biodentine, MTA Plus, and resin modified glass ionomer cement used as dentin substitutes and reports better adaptation obtained with Biodentine and glass ionomer cement. © 2015 Wiley Periodicals, Inc.

  8. Three different signal amplification strategies for the impedimetric sandwich detection of thrombin

    Energy Technology Data Exchange (ETDEWEB)

    Ocaña, Cristina; Valle, Manel del, E-mail: manel.delvalle@uab.cat

    2016-03-17

    In this work, we report a comparative study on three highly specific amplification strategies for the ultrasensitive detection of thrombin with the use of aptamer sandwich protocol. The protocol consisted on the use of a first thrombin aptamer immobilized on the electrode surface, the recognition of thrombin protein, and the reaction with a second biotinylated thrombin aptamer forming the sandwich. Through the exposed biotin end, three variants have been tested to amplify the electrochemical impedance signal. The strategies included (a) silver enhancement treatment, (b) gold enhancement treatment and (c) insoluble product produced by the combination of the enzyme horseradish peroxidase (HRP) and 3-amino-9-ethylcarbazole (AEC). The properties of the sensing surface were probed by electrochemical impedance measurements in the presence of the ferrocyanide/ferricyanide redox marker. Insoluble product strategy and silver enhancement treatment resulted in the lowest detection limit (0.3 pM), while gold enhancement method resulted in the highest reproducibility, 8.8% RSD at the pM thrombin concentration levels. Results of silver and gold enhancement treatment also permitted direct inspection by scanning electron microscopy (SEM). - Highlights: • Aptasensor to detect thrombin reaching the femtomolar level. • Biosensing protocol employs two thrombin aptamers in a sandwich capture scheme. • Use of second biotinylated aptamer allows many amplification and detection variants. • Precipitation reaction provides the highest signal amplification of ca. 3 times. • Double recognition event improves remarkably selectivity for thrombin detection.

  9. Flexible freestanding sandwich type ZnO/rGO/ZnO electrode for wearable supercapacitor

    Science.gov (United States)

    Ghorbani, Mina; Golobostanfard, Mohammad Reza; Abdizadeh, Hossein

    2017-10-01

    The development of flexible supercapacitors with high energy and power density as one of the main components of wearable electronics is in an enormous interest. In this report, a unique flexible electrode based on freestanding sandwich type ZnO/rGO/ZnO paper is fabricated by a simple low cost sol-gel method for utilizing in flexible supercapacitor. ZnO layers are deposited on both sides of rGO paper which is prepared by a modified Hummer's method and evaporation induced assembly. The uniform and densely packed ZnO layers are formed on graphene oxide paper and the paper is simultaneously reduced. Structural analysis reveals the formation of ZnO thin films on both sides of rGO nanosheets, which leads to the sandwich architecture. Also, the effect of ZnO sol-gel process parameters on microstructure of sandwich paper are investigated and the most suitable condition for highest supercapacity performance is the solvent of 1-PrOH, stabilizer of TeA, sol concentration of 0.2 M, deposition speed of 30 mm min-1, and 10 deposited layers. The results of electrochemical impedance spectroscopy, galvanostatic charge-discharge, and cyclic voltammetry confirm that the incorporation of ZnO improves the capacitive performance of rGO electrode. Moreover, ZnO/rGO/ZnO flexible electrode exhibits suitable capacitance value of 60.63 F g-1 at scan rate of 5 mV/s.

  10. Wave propagation in sandwich panels with a poroelastic core.

    Science.gov (United States)

    Liu, Hao; Finnveden, Svante; Barbagallo, Mathias; Arteaga, Ines Lopez

    2014-05-01

    Wave propagation in sandwich panels with a poroelastic core, which is modeled by Biot's theory, is investigated using the waveguide finite element method. A waveguide poroelastic element is developed based on a displacement-pressure weak form. The dispersion curves of the sandwich panel are first identified as propagating or evanescent waves by varying the damping in the panel, and wave characteristics are analyzed by examining their motions. The energy distributions are calculated to identify the dominant motions. Simplified analytical models are also devised to show the main physics of the corresponding waves. This wave propagation analysis provides insight into the vibro-acoustic behavior of sandwich panels lined with elastic porous materials.

  11. A Debonded Sandwich Specimen Under Mixed Mode Bending (MMB)

    DEFF Research Database (Denmark)

    Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

    2008-01-01

    Face/core interface crack propagation in sandwich specimens is analyzed. A thorough analysis of the typical failure modes in sandwich composites was performed in order to design the MMB specimen to promote face/core debond fracture. Displacement, compliance and energy release rate expressions...... for the MMB specimen were derived from a superposition analysis. An experimental verification of the methodology proposed was performed using MMB sandwich specimens with H100 PVC foam core and E-glass/polyester non-crimp quadro-axial [0/45/90/-45]s DBLT-850 faces. Different mixed mode loadings were applied...

  12. Measuring Cohesive Laws for Interfaces in Sandwich Structures

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Sørensen, Bent F.; Berggreen, Carl Christian

    2006-01-01

    Extraction of cohesive laws are conducted for interfaces in sandwich structures. Separation between face and core are driven by pure bending moments applied to double cantilever beam (DCB) specimens. By varying the ratio between moments applied to the beams the test is conducted for different mode...... mixities. The sandwich specimens consists of glass fiber faces and Divinycell H200 foam core with a pre-crack between face and core made with teflon film. Arbitrary stiffening of the sandwich faces with steel bars adhered to the faces reduces rotations and ensures that the method is useable for a wide...

  13. A Debonded Sandwich Specimen Under Mixed Mode Bending (MMB)

    DEFF Research Database (Denmark)

    Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

    2008-01-01

    Face/core interface crack propagation in sandwich specimens is analyzed. A thorough analysis of the typical failure modes in sandwich composites was performed in order to design the MMB specimen to promote face/core debond fracture. Displacement, compliance and energy release rate expressions...... for the MMB specimen were derived from a superposition analysis. An experimental verification of the methodology proposed was performed using MMB sandwich specimens with H100 PVC foam core and E-glass/polyester non-crimp quadro-axial [0/45/90/-45]s DBLT-850 faces. Different mixed mode loadings were applied...

  14. Measuring Cohesive Laws for Interfaces in Sandwich Structures

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Sørensen, Bent F.; Berggreen, Carl Christian

    2006-01-01

    Extraction of cohesive laws are conducted for interfaces in sandwich structures. Separation between face and core are driven by pure bending moments applied to double cantilever beam (DCB) specimens. By varying the ratio between moments applied to the beams the test is conducted for different mode...... mixities. The sandwich specimens consists of glass fiber faces and Divinycell H200 foam core with a pre-crack between face and core made with teflon film. Arbitrary stiffening of the sandwich faces with steel bars adhered to the faces reduces rotations and ensures that the method is useable for a wide...

  15. Thermal behavior of a titanium honeycomb-core sandwich panel

    Science.gov (United States)

    Ko, William L.; Jackson, Raymond H.

    1991-01-01

    Finite element thermal stress analysis was performed on a rectangular titanium honecomb-core sandwich panel which is subjected to thermal load with a temperature gradient across its depth. The distributions of normal stresses in the face sheets and the face-sheet/sandwich-core interfacial shear stresses are presented. The thermal buckling of the heated face sheet was analyzed by assuming the face sheet to be resting on an elastic foundation representing the sandwich core. Thermal buckling curves and thermal buckling load surface are presented for setting the limit for temperature gradient across the panel depth.

  16. Sandwich Panel as a Structural Element of Overlap

    Directory of Open Access Journals (Sweden)

    Novikov Maxim

    2016-01-01

    Full Text Available This paper considers the issue of sandwich panels using as load-bearing structural elements. The comparison of deflections and critical failure loads were obtained by the results of the full-scale roof sandwich panels tests conducted by the company “Joris Ide” and the theoretical design, according to the calculation method described in Euronorms. Based on these results it was concluded that sandwich panels can be treated as a load-bearing structure only with more taught manufacturing requirements. Thus, the reduced spread of critical loads can be achieved.

  17. 侵染水鬼蕉和花朱顶红的番茄斑萎病毒属病毒的电镜和DAS-ELISA诊断%DAS-ELISA and Electron Microscopic Diagnosis of Tospoviruses Infecting Hymenocallis littoraris and Hippeastrum vittatum in Kunming

    Institute of Scientific and Technical Information of China (English)

    方琦; 董家红; 丁铭; 尹跃艳; 张丽珍; 李婷婷; 苏晓霞; 李展; 张仲凯

    2011-01-01

    从昆明市郊区采集到呈同心圆褪绿环斑、褐色枯斑症状的水鬼蕉[Hymenocallis littoraris(Jacq.)Salisb.]和花朱顶红[Hippeastrum vittatum(L’Hér.)Herb.]植株,采用电子显微镜技术和DAS-ELISA进行检测,在水鬼蕉和花朱顶红病叶分离物SGJ-KM和ZDH-KM的粗汁液和超薄切片中均观察到有类似番茄斑萎病毒属(Tospovirus)病毒粒体存在,该病毒粒子为球形,直径80~85nm;病叶汁液与Tospovirus中的西瓜银色斑驳病毒(Watermelon silver mottle virus,WSMoV)/花生芽坏死病毒(Groundnut bud necrosis virus,GBNV)的复合抗血清呈阳性反应。通过形态学及血清学方法检测表明,侵染水鬼蕉和花朱顶红的病毒分离物SGJ-KM和ZDH-KM为Tospovirus的病毒分离物。%The leaves of Hymenocallis littoraris(Jacq.)Salisb.and Hippeastrum vittatum(L'Hér.) Herb.,showing concentric chlorotic ring spot and brown lethal spot symptoms,were collected in Kunming.To confirm the presence of virus,the SGJ-KM and ZDH-KM infected leaves of H.littoraris and H.vittatum were detected by electron microscope observation and DAS-ELISA.Virions with a diameter of about 80-85 nm,similar in size to Tospovirus particles,were observed in the crude extracts and ultrathin sections of diseased leaves of H.littoraris and H.vittatum.The sap of diseased leaves had a positive reaction to the compound antibody of Watermelon silver mottle virus,WSMoV/Groundnut bud necrosis virus,GBNV.These results confirmed that H.littoraris and H.vittatum were infected by Tospoviruses.

  18. Anomalous photoluminescence thermal quenching of sandwiched single layer MoS_2

    KAUST Repository

    Tangi, Malleswara

    2017-09-22

    We report an unusual thermal quenching of the micro-photoluminescence (µ-PL) intensity for a sandwiched single-layer (SL) MoS2. For this study, MoS2 layers were chemical vapor deposited on molecular beam epitaxial grown In0.15Al0.85N lattice matched templates. Later, to accomplish air-stable sandwiched SL-MoS2, a thin In0.15Al0.85N cap layer was deposited on the MoS2/In0.15Al0.85N heterostructure. We confirm that the sandwiched MoS2 is a single layer from optical and structural analyses using µ-Raman spectroscopy and scanning transmission electron microscopy, respectively. By using high-resolution X-ray photoelectron spectroscopy, no structural phase transition of MoS2 is noticed. The recombination processes of bound and free excitons were analyzed by the power-dependent µ-PL studies at 77 K and room temperature (RT). The temperature-dependent micro photoluminescence (TDPL) measurements were carried out in the temperature range of 77 – 400 K. As temperature increases, a significant red-shift is observed for the free-exciton PL peak, revealing the delocalization of carriers. Further, we observe unconventional negative thermal quenching behavior, the enhancement of the µ-PL intensity with increasing temperatures up to 300K, which is explained by carrier hopping transitions that take place between shallow localized states to the band-edges. Thus, this study renders a fundamental insight into understanding the anomalous thermal quenching of µ-PL intensity of sandwiched SL-MoS2.

  19. Successful mouse hepatocyte culture with sandwich collagen gel formation

    National Research Council Canada - National Science Library

    Choi, Hyun Jung; Choi, Dongho

    2013-01-01

    .... However, long-term cultures of functional hepatocytes are difficult to establish. To increase the longevity and maintain the differentiated functions of hepatocytes in primary culture, cells can be cultured in a sandwich configuration of collagen...

  20. Outcome of the TURP-TUVP sandwich procedure for minimally ...

    African Journals Online (AJOL)

    shanker

    TURP–TUVP sandwich procedure for the surgical treatment of BPH larger than 40cc in ... volume larger than 40cc had satisfactory patient safety profile and resulted in .... ment, nursing contact time, and duration of catheterization, besides.

  1. Sandwich-like reconstruction of anterior skull base defects

    Institute of Scientific and Technical Information of China (English)

    WANG Zhengmin; WANG Dehui

    2002-01-01

    @@ RESULTS From October, 1984 to October, 1998, 116 patients underwent transcranial or transcranial-facial approach for the resection of malignant or benign aggressive tumor, and sandwich-like repairs were performed for the anterior skull base defect.

  2. Mechanical and vibro-acoustic aspects of composite sandwich cylinders

    NARCIS (Netherlands)

    Yuan, C.

    2013-01-01

    Designing a fuselage involves many considerations such as strength and stability, fatigue, damage tolerance, fire and lightning resistance, thermal and acoustic insulation, production, inspection, maintenance and repair. In the background of the application of composite sandwich structures on the ai

  3. Mechanical and vibro-acoustic aspects of composite sandwich cylinders

    NARCIS (Netherlands)

    Yuan, C.

    2013-01-01

    Designing a fuselage involves many considerations such as strength and stability, fatigue, damage tolerance, fire and lightning resistance, thermal and acoustic insulation, production, inspection, maintenance and repair. In the background of the application of composite sandwich structures on the ai

  4. Observability and Controllability Analysis for Sandwich Systems with Backlash

    Directory of Open Access Journals (Sweden)

    Luo Na

    2015-12-01

    Full Text Available In this paper, an approach to analyze the observability and controllability of sandwich systems with backlash is proposed. In this method, a non-smooth state-space function is used to describe the sandwich systems with backlash which are also non-smooth non-linear systems. Then, a linearization method based on non-smooth optimization is proposed to derive a linearized state-space function to approximate the non-smooth sandwich systems within a bounded region around the equilibrium point that we are interested in. Afterwards, both observability and controllability matrices are constructed and the methods to analyze the observability as well as controllability of sandwich system with backlash are derived. Finally, numerical examples are presented to validate the proposed method.

  5. Mechanical and vibro-acoustic aspects of composite sandwich cylinders

    NARCIS (Netherlands)

    Yuan, C.

    2013-01-01

    Designing a fuselage involves many considerations such as strength and stability, fatigue, damage tolerance, fire and lightning resistance, thermal and acoustic insulation, production, inspection, maintenance and repair. In the background of the application of composite sandwich structures on the

  6. Residual Strength Prediction of Debond Damaged Sandwich Panels

    DEFF Research Database (Denmark)

    Berggreen, Carl Christian

    This presentation concerns theoretical and experimental prediction of crack propagation and residual strength of debond damaged sandwich panels. It is evident that in order to achieve highly optimised structures which are able to operate in a stochastic loading environment, damage tolerance...... propagation and initiation, as these mechanisms are governing for the overall failure load of the structure. Thus, this presentation will describe the development, validation and application of a FEM based numerical model for prediction of residual strength of damaged sandwich panels. The core......, but they are especially relevant for sandwich structures which by nature are highly optimised structures with a high number of possible damage scenarios and consequent failure mechanisms. A major challenge in estimation of structural integrity of damaged sandwich structures is modelling and prediction of crack...

  7. Fracture Characterization of Sandwich Face/Core Interfaces

    DEFF Research Database (Denmark)

    Manca, Marcello

    such result it is important to devise new experimental and analytical techniques to establish the multi-mode fracture characteristics of sandwich plate structures and accordingly develop methods to inhibit defect propagation. This thesis deals with characterization of fracture between face and core...... samples. A number of sandwich materials were tested (GFRP/foam cores and CFRP/Nomex) bothin static and fatigue. A linear elastic fracture mechanics model was used to determine the analyticalexpression of compliance which allowed to calculate automatically the crack length. In combination, a finite element...... types of sandwich samples atdifferent mode mixities and ΔG levels, and results in agreement with previous studies were obtained suggesting that the developed testing method is a reliable tool for the study of face/core interface debonded sandwich structures....

  8. Forced vibration of a shear thickening fluid sandwich beam

    Science.gov (United States)

    Wei, Minghai; Hu, Gang; Jin, Lu; Lin, Kun; Zou, Dujian

    2016-05-01

    The forced vibration of a sandwich beam integrating a shear thickening fluid (STF) core and with conductive skins subjected to a periodic excitation was investigated theoretically in this study. The rheological properties of the STF material including viscosity, plasticity, and elasticity may be changed under the periodic vibration, and hence they were considered. The governing equation of motion was derived based on the complex stiffness method and some key parameters were derived based on the Timoshenko beam theory. Effects of the excitation frequency, the excitation amplitude, the excitation location, and the skin/core thickness ratio on the nature frequency of the sandwich beam were investigated. It was found that the STF core has a significant effect on the dynamic property of the sandwich beam. Based on the findings, integrating the STF core in a sandwich beam can reduce the vibration of the beam.

  9. A novel sandwich electrochemiluminescence immunosensor for ultrasensitive detection of carbohydrate antigen 19-9 based on immobilizing luminol on Ag@BSA core/shell microspheres.

    Science.gov (United States)

    Zhang, Amin; Xiang, Hongkun; Zhang, Xin; Guo, Weiwei; Yuan, Enhui; Huang, Chusen; Jia, Nengqin

    2016-01-15

    A novel sandwich-type electrochemiluminescence immunosensor based on immobilizing luminol on Ag@BSA core/shell microspheres (Ag@BSA-luminol) for ultrasensitive detection of tumor marker carbohydrate antigen 19-9 (CA19-9) has been developed. Herein, magnetic carbon nanotubes (MAGCNTs) decorated with polyethylenimine (PEI) was used to construct the base of the immunosensor. MAGCNTs with prominent electrical conductivity and high surface area could be beneficial for promoting the electron transfer and loading plenty of primary antibodies (Ab1) via glutaraldehyde (GA). Meanwhile, the magnetic property of MAGCNTs makes it easy to be attached to the surface of magnetic glass carbon electrode (MGCE) through magnetism interaction, which provides an outstanding platform for this immunosensor. Moreover, Ag@BSA microspheres with large surface area, good stability, and excellent biocompatibility were desirable candidates for effective cross-link of CA19-9 detection antibodies (Ab2). A more interesting thing was that ELISA color reaction was used as an ultrasensitive strategy for identifying Ab2 was successfully coated on Ag@BSA with the naked eye. Additionally, we immobilized the luminol on the surface of Ag@BSA to prepare the target immunosensor. Immobilization of luminol on the surface of Ag@BSA could decrease the distance between luminophores and the electrode surface, leading to great enhancement of the ECL intensity of luminol in the present of hydrogen peroxide (H2O2). Under the optimal conditions, the intensity of the ECL immunosensor increased linearly with the logarithm of CA19-9 concentration in a wide linear range from 0.0005 to 150UmL(-1) with a detection limit of 0.0002UmL(-1) (S/N=3). All the results suggested the prepared CA19-9 immunosensor displayed high sensitivity, excellent stability and good specificity. The developed method opened a new avenue to clinical bioassay.

  10. Detección de antígenos de la larva de Taenia solium mediante la Técnica de Elisa

    Directory of Open Access Journals (Sweden)

    Carmenza Murillo

    2010-07-01

    Full Text Available Se describe la optimización de las variables en un ELISA sandwich asimétrico para la detección de antígenos circulantes de larva de Taenia solium empleado como estándar líquido intraquístico obtenido del parásito y como suero itunune anticisticerco absorbido con líquido cefalorraquídeo (LCR normal lo que permite detectar 50 ng/ mi de antígeno. Se utilizaron muestras de LCR liofilizadas; bajo estas condiciones de almacenamiento la especificidad obtenida fue del 63% al analizar 24 LCR negativos para neurocisticercosis por tromografía computarizada cerebral, y 15 LCR de pacientes que mostraban calcificaciones. El coeficiente de variación interensayo está dentro de los límites aceptados para el ELISA.

  11. Evaluation of accuracy and uncertainty of ELISA assays for the determination of interleukin-4, interleukin-5, interferon-gamma and tumor necrosis factor-alpha

    DEFF Research Database (Denmark)

    Borg, Lone; Kristiansen, Jesper; Christensen, Jytte M

    2002-01-01

    . However, models for establishing the traceability and uncertainty of immunoassay results are lacking. Sandwich enzyme-linked immunosorbent assays (ELISAs) were developed for determination of the human cytokines interleukin-4 (IL-4), interleukin-5 (IL-5), interferon-y (IFN-gamma) and tumor necrosis factor......) of the assessed ELISAs was found to be in the range of 11-18%, except for IL-5 where RSDA increased at decreasing concentrations. The LOD was 0.12 microg/l, 0.0077 microg/l, 0.0069 microg/l and 0.0063 microg/l for IL-4, IL-5, IFN-gamma and TNF-alpha, respectively. Traceability to the WHO IS was established...

  12. Immunological techniques: ELISA, flow cytometry, and immunohistochemistry.

    Science.gov (United States)

    Ford, Pauline J

    2010-01-01

    Techniques to analyze the host immune response elicited by the presence of oral microorganisms and their products are central to our understanding of the local and systemic effects of oral diseases. This immune response has been extensively investigated for periodontal disease. The local response may result in lesions involving the gingival tissues and depending upon host susceptibility and microbial virulence may lead to local tissue destruction. More recently, however, the importance of the systemic inflammatory and immune response to oral organisms has been recognized. These systemic responses have been associated with an increased risk for cardiovascular disease, diabetes, and preterm low birth weight. A number of techniques are used extensively by researchers investigating humoral and cellular immune responses to oral organisms both in local oral tissues and fluids and systemically in peripheral blood. These are enzyme-linked immunosorbent assay (ELISA) to quantify specific antibody and cytokines in serum, gingival crevicular fluid (GCF), and saliva; characterization of T cells from peripheral blood and gingival tissues using flow cytometry; and immunohistological analysis of the inflammatory cell infiltrate in gingival tissues.

  13. Gold nanoparticle-based enzyme-linked antibody-aptamer sandwich assay for detection of Salmonella Typhimurium.

    Science.gov (United States)

    Wu, Wenhe; Li, Jun; Pan, Dun; Li, Jiang; Song, Shiping; Rong, Mingge; Li, Zixi; Gao, Jimin; Lu, Jianxin

    2014-10-01

    Enzyme-linked immunosorbent assay (ELISA) provides a convenient means for the detection of Salmonella enterica serovar Typhimurium (STM), which is important for rapid diagnosis of foodborne pathogens. However, conventional ELISA is limited by antibody-antigen immunoreactions and suffers from poor sensitivity and tedious sample pretreatment. Therefore, development of novel ELISA remains challenging. Herein, we designed a comprehensive strategy for rapid, sensitive, and quantitative detection of STM with high specificity by gold nanoparticle-based enzyme-linked antibody-aptamer sandwich (nano-ELAAS) method. STM was captured and preconcentrated from samples with aptamer-modified magnetic particles, followed by binding with detector antibodies. Then nanoprobes carrying a large amount of reporter antibodies and horseradish peroxidase molecules were used for colorimetric signal amplification. Under the optimized reaction conditions, the nano-ELAAS assay had a quantitative detection range from 1 × 10(3) to 1 × 10(8) CFU mL(-1), a limit of detection of 1 × 10(3) CFU mL(-1), and a selectivity of >10-fold for STM in samples containing other bacteria at higher concentration with an assay time less than 3 h. In addition, the developed nanoprobes were improved in terms of detection range and/or sensitivity when compared with two commercial enzyme-labeled antibody signal reporters. Finally, the nano-ELAAS method was demonstrated to work well in milk samples, a common source of STM contamination.

  14. Development of monoclonal antibodies and quantitative sandwich enzyme linked immunosorbent assay for the characteristic sialoglycoprotein of edible bird's nest.

    Science.gov (United States)

    Zhang, Shiwei; Lai, Xintian; Liu, Xiaoqing; Li, Yun; Li, Bifang; Huang, Xiuli; Zhang, Qinlei; Chen, Wei; Lin, Lin; Yang, Guowu

    2013-01-01

    The article presents a sandwich enzyme linked immunosorbent assay (ELISA) for identification of edible bird's nest. The characteristic sialoglycoproteins were found by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and purified by liquid-phase isoelectric focusing (LIEF). According to the analysis, the molecular weight was 106-128 kDa and the isoelectric point was ≤pH 3.0. Two anti-characteristic sialoglycoprotein monoclonal antibodies were produced. The monoclonal antibodies were examined by western-blot assay. One of the monoclonal antibody was used as coating and the other as the enzyme-labeled antibody after being coupled to horseradish peroxidase (HRP). Based on the optimized ELISA condition, the method was established with IC(50) of 1.5 ng/mL, and low cross-reactivity with various fake materials (ELISA provided a suitable means for screening of a large number of samples. The coefficients of variation were between 2.9% and 5.8%.

  15. Lightweight Sandwich Panel in Cold Stores and Refrigerated Warehouses

    OpenAIRE

    Chidom, Charles

    2013-01-01

    The use of sandwich panels has gained considerable recognition in the construction industry and more use of this composite structure is ever increasing. This study highlights and familiarizes the use of lightweight sandwich panel in refrigerated warehouses and cold storage facility and construction and the challenges such construction faces in warm climates considering the effects of thermal load. The study was commissioned by HAMK Sheet Metal Center, the steel research and development ce...

  16. Optimization of composite sandwich cover panels subjected to compressive loadings

    Science.gov (United States)

    Cruz, Juan R.

    1991-01-01

    An analysis and design method is presented for the design of composite sandwich cover panels that include the transverse shear effects and damage tolerance considerations. This method is incorporated into a sandwich optimization computer program entitled SANDOP. As a demonstration of its capabilities, SANDOP is used in the present study to design optimized composite sandwich cover panels for for transport aircraft wing applications. The results of this design study indicate that optimized composite sandwich cover panels have approximately the same structural efficiency as stiffened composite cover panels designed to satisfy individual constraints. The results also indicate that inplane stiffness requirements have a large effect on the weight of these composite sandwich cover panels at higher load levels. Increasing the maximum allowable strain and the upper percentage limit of the 0 degree and +/- 45 degree plies can yield significant weight savings. The results show that the structural efficiency of these optimized composite sandwich cover panels is relatively insensitive to changes in core density. Thus, core density should be chosen by criteria other than minimum weight (e.g., damage tolerance, ease of manufacture, etc.).

  17. Comparison of dot-ELISA and standard ELISA for detection of Neisseria meningitidis outer membrane complex-specific antibodies

    OpenAIRE

    Elza FT Belo; Farhat,Calil K; De Gaspari,Elizabeth N.

    2010-01-01

    Dot-ELISA using the outer membrane complex antigens of Neisseria meningitidis as a target was standardized for rapid detection of meningococcal-specific antibodies in human serum. We investigated the level of meningococcal-specific IgG, IgA, and IgM in serum using dot-ELISA with outer membrane antigens prepared from Neisseria meningitidis serotype B:4.19:P1.15,3,7,9 (a strain isolated from a Brazilian epidemic). The dot-ELISA is based on the same principles as the standard ELISA and is useful...

  18. A study of structurally efficient graphite-thermoplastic trapezoidal-corrugation sandwich and semi-sandwich panels

    Science.gov (United States)

    Jegley, Dawn C.

    1993-01-01

    The structural efficiency of compression-loaded trapezoidal-corrugation sandwich and semi-sandwich composite panels is studied to determine their weight savings potential. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semi-sandwich panels with a corrugation attached to a single skin are considered. An optimization code is used to find the minimum weight designs for critical compressive load levels ranging from 3,000 to 24,000 lb/in. Graphite-thermoplastic panels based on the optimal minimum weight designs were fabricated and tested. A finite-element analysis of several test specimens was also conducted. The results of the optimization study, the finite-element analysis, and the experiments are presented.

  19. Development of a Fibrinogen-Specific Sandwich Enzyme-Linked Immunosorbent Assay Microarray Assay for Distinguishing Between Blood Plasma and Serum Samples

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, Rachel M.; Zhang, Qibin; Zangar, Richard C.; Smith, Richard D.; Metz, Thomas O.

    2011-07-01

    We have developed a fibrinogen-specific sandwich ELISA microarray assay for use in qualitatively distinguishing between blood plasma and serum samples. Three capture antibodies, 49D2, HPA001900, and F8512, were evaluated in conjunction with 1D6 as detection antibody, and the data show that 49D2 and, to a lesser extent, F8512 successfully identify previously unknown plasma and serum samples based upon a ~28-fold difference in signal intensity between the sample types. This assay has utility in rapidly identifying previously archived clinical samples with incomplete annotation in a high throughput manner prior to proteomics analyses.

  20. Ab initio study of DNA nucleotides sandwiched between Au(111) electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bogdan, Diana; Bratfalean, Radu; Isai, Radu; Morari, Cristian, E-mail: cristian.morari@itim-cj.r [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

    2009-08-01

    Using first-principles calculations, we study the electronic properties of the four DNA nucleotides sandwiched between two Au(111) electrodes. The geometrical structure of the systems is a realistic model of the recently proposed devices for DNA sequencing. For these metal-molecule-metal systems, we calculate the total and local density of states (DOS, LDOS), and the metal-molecule charge transfers. Our results suggest that the qualitative differences between the four systems are sufficient to ensure the recognition of the DNA bases by the proposed device. Nevertheless, the full investigation of the quantitative features of the current-voltage curves is needed to decide if the practical use is possible.

  1. Atomically thick Pt-Cu nanosheets: self-assembled sandwich and nanoring-like structures.

    Science.gov (United States)

    Saleem, Faisal; Xu, Biao; Ni, Bing; Liu, Huiling; Nosheen, Farhat; Li, Haoyi; Wang, Xun

    2015-03-25

    Atomically thick and flexible Pt-Cu alloy nanosheets are prepared and loaded with either Pd or Pt to produce sandwich structures or nanoring-like nanosheet structures, respectively. Core-shell alloy nanoparticles containing Rh, Ir, and Ru are also prepared. All of these structures exhibit superior specific and mass activities for the oxidation of formic acid for fuel cells for portable electronic devices as compared to commercial Pd/C catalyst. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays.

    Science.gov (United States)

    Vance, Stephen; Zeidan, Effat; Henrich, Vincent C; Sandros, Marinella G

    2016-01-07

    Sensitive and selective methods for the detection of human growth hormone (hGH) over a wide range of concentrations (high levels of 50-100 ng ml(-) (1) and minimum levels of 0.03 ng ml(-) (1)) in circulating blood are essential as variable levels may indicate altered physiology. For example, growth disorders occurring in childhood can be diagnosed by measuring levels of hGH in blood. Also, the misuse of recombinant hGH in sports not only poses an ethical issue it also presents serious health threats to the abuser. One popular strategy for measuring hGH misuse, relies on the detection of the ratio of 22 kDa hGH to total hGH, as non-22 kDa endogenous levels drop after exogenous recombinant hGH (rhGH) administration. Surface plasmon resonance imaging (SPRi) is an analytical tool that allows direct (label-free) monitoring and visualization of biomolecular interactions by recording changes of the refractive index adjacent to the sensor surface in real time. In contrast, the most frequently used colorimetric method, enzyme-linked immunosorbent assay (ELISA) uses enzyme labeled detection antibodies to indirectly measure analyte concentration after the addition of a substrate that induces a color change. To increase detection sensitivity, amplified SPRi uses a sandwich assay format and near infrared quantum dots (QDs) to increase signal strength. After direct SPRi detection of recombinant rhGH in spiked human serum, the SPRi signal is amplified by the sequential injection of detection antibody coated with near-infrared QDs (Nano-SPRi). In this study, the diagnostic potential of direct and amplified SPRi was assessed for measuring rhGH spiked in human serum and compared directly with the capabilities of a commercially available ELISA kit.

  3. N-doped graphene-SnO{sub 2} sandwich paper for high-performance lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi; Chen, Shimou; Tang, Dai-Ming; Zhai, Tianyou; Li, Liang; Bando, Yoshio; Golberg, Dmitri [International Center for Young Scientists (ICYS) and International Center for Materials, Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Cao, Xinqiang; Zhong, Yeteng [Beijing National Laboratory for Molecular Science, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Bourgeois, Laure [Monash Centre for Electron Microscopy and Department of Materials Engineering, Monash University, VIC 3800 (Australia); Guan, Hasigaowa [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); Li, Huiqiao [Energy Technology Research Institute, National Institute of Advanced Industry and Technology (AIST), Umezono, 1-1-1, Tsukuba (Japan)

    2012-07-10

    A new facile route to fabricate N-doped graphene-SnO{sub 2} sandwich papers is developed. The 7,7,8,8-tetracyanoquinodimethane anion (TCNQ{sup -}) plays a key role for the formation of such structures as it acts as both the nitrogen source and complexing agent. If used in lithium-ion batteries (LIBs), the material exhibits a large capacity, high rate capability, and excellent cycling stability. The superior electrochemical performance of this novel material is the result from its unique features: excellent electronic conductivity related to the sandwich structure, short transportation length for both lithium ions and electrons, and elastomeric space to accommodate volume changes upon Li insertion/extraction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. DETERMINATION OF HISTAMINE IN FISH USING ELISA TECHNIQUE

    NARCIS (Netherlands)

    KRUGER, C; SEWING, U; STENGEL, G; KEMA, [No Value; WESTERMANN, J; MANZ, B

    1995-01-01

    The analysis of histamine in fish and fish products via competitive ELISA is described. The advantages of this method are easy sample preparation and handling, screening capabilities, and low costs. Automation enables the performance of the assay with higher series of samples. The Histamine-ELISA is

  5. A micro ELISA for the diagnosis of cerebral cisticercosis.

    Science.gov (United States)

    Nunez, R; Munoz, A; Nunez, C; Gomez, B

    1989-01-01

    A micro ELISA for cysticercosis in the central nervous system was evaluated in 24 patients and compared with indirect hemagglutination. CSF ELISA results were positive in 17 of 20 patients (sensitivity 85%), whereas CSF indirect hemagglutination was positive in only 14 patients (sensitivity 70%).

  6. Quantitative determination of VEGF165 in cell culture medium by aptamer sandwich based chemiluminescence assay.

    Science.gov (United States)

    Shan, Siwen; He, Ziyi; Mao, Sifeng; Jie, Mingsha; Yi, Linglu; Lin, Jin-Ming

    2017-08-15

    In this work, we have developed a sensitive and selective chemiluminescence (CL) assay for vascular endothelial growth factor (VEGF165) quantitative detection based on two specific VEGF165 binding aptamers (Apt). VEGF is a predominant biomarker in cancer angiogenesis, and sensitive detection method of VEGF are highly demanded for both academic study and clinical diagnosis of multiple cancers. In our experiment, VEGF165 was captured in a sandwich structure assembled by two binding aptamers, one capture aptamer was immobilized on streptavidin-coated magnetic beads (MBs) and another VEGF-binding aptamer was labeled by biotin for further phosphatase conjunction. After Apt-VEGF-Apt sandwich was formed on MBs surface, alkaline phosphatase (ALP) was modified to the second aptamer to catalyze CL reaction. By applying 4-methoxy-4-(3-phosphatephenyl)-spiro-(1,2-dioxetane-3,2-adamantane) (AMPPD) as CL substrate, strong signal intensity was achieved. VEGF165 content as low as 1ng/mL was detected in standard spiked samples by our assay, and linear range of working curve was confirmed from 1 to 20ng/mL. Then our method was successfully applied for cell culture medium analysis and on-chip hypoxic HepG2-HUVEC co-culture model study with excellent accuracy equal to ELISA Kit. Our developed assay demonstrated an outstanding performance in VEGF165 quantification and may be further extended to clinical testing of important biomarkers as well as probing microchip cell culture model. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Determination of polychlorinated biphenyls (PCBs) in insulating oil by cocktail PCB ELISA

    Energy Technology Data Exchange (ETDEWEB)

    Goda, Y.; Hirobe, M.; Fujimoto, S. [Japan EnviroChemicals Ltd., Tokyo (Japan); Tomita, J.; Nishikiori, M.; Nakajima, T. [Tokyo Electric Power Environmental Engineering Co. Inc., Tokyo (Japan); Rubio, F. [Abraxis LLC, Warminster, PA (United States); Takigami, H. [National Inst. for Environmental Studies, Tsukuba (Japan); Sakai, S. [Kyoto Univ., Kyoto (Japan). Environment Preservation Centre; Ike, M.; Fujita, M. [Osaka Univ., Osaka (Japan). Graduate School of Engineering

    2005-07-01

    This paper described a novel cocktail polychlorinated biphenyl (PCB) enzyme-linked immunosorbent assay (ELISA) designed as a simple pretreatment method for the determination of PCBs in insulating oils. Oil samples were treated with hexane and dimethyl sufloxide (DMSO) and mixed. Hexane layers were then removed, and freshly prepared hexane was added. The DMSO layer was then diluted with an aqueous solution and extracted with hexane. After being dehydrated, the hexane layer was sulfonated with a sulfuric reagent and washed. Standard or pretreated PCBs were then dissolved and diluted in 100 per cent DMSO and added to distilled water prior to the ELISA assay. A horseradish peroxidase conjugate and an anti-PCB antibody coupled with magnetic particles were added for the assay. A magnetic rack was used to separate the reaction mixture. A colouring reagent was then added. A total of 26 insulating oils contaminated with PCBs were determined using the new cocktail method and compared with data obtained from traditional gas chromatograph electron capture detector (GC-ECD) data. Results showed that the values of both the cocktail and general PCB ELISA were well correlated with the CG-ECD data. It was concluded that combining cocktail PCB ELISA with the developed pretreatment method provided accurate results. 3 refs., 4 tabs., 2 figs.

  8. Preparation, magnetism and microwave absorption performance of ultra-thin Fe{sub 3}O{sub 4}/carbon nanotube sandwich buckypaper

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shaowei, E-mail: lushaowei_2005@163.com; Xu, Weikai; Xuhai, Xiong; Ma, Keming; Wang, Xiaoqiang

    2014-09-01

    Graphical abstract: Fe{sub 3}O{sub 4}/multi-walled carbon nanotubes (MWCNTs) sandwich buckypapers were fabricated with monodispersion solutions of MWCNTs and Fe{sub 3}O{sub 4} nanoparticles through layer by layer vacuum filtration method. The Fe{sub 3}O{sub 4}/MWCNTs sandwich buckypaper can be co-cured on the surface of fiber reinforce composites and exhibits excellent magnetism and microwave absorbing ability only with a 0.1 mm thickness absorbing layer. - Highlights: • Sandwich buckypapers were fabricated with MWCNTs/Fe{sub 3}O{sub 4} monodispersions through vacuum filtration. • Composite with a 0.1 mm thickness sandwich buckypaper exhibits strong microwave absorbing ability. • The sandwich buckypaper has higher magnetic loss and suitable dielectric loss. • The sandwich buckypaper can fulfil the impedance matching and attenuation characteristics. - Abstract: Fe{sub 3}O{sub 4}/multi-walled carbon nanotubes (MWCNTs) sandwich buckypapers were fabricated with monodisperse solutions of MWCNTs and Fe{sub 3}O{sub 4} nanoparticles through layer by layer vacuum filtration method and can be co-cured with composites for microwave absorbing application. The morphology, element composition and magnetic properties of sandwich buckypapers were characterized by field-emission scanning electron microscope, energy dispersive spectrometer, X-ray diffraction and vibrating sample magnetometer. The complex permittivity and permeability, the reflection loss properties of polymer composites surface coated buckypapers were investigated in the frequency range of 8.2–18 GHz. The results indicate that, due to the electromagnetic matching of magnetic loss and dielectric loss, the microwave absorption properties of the Fe{sub 3}O{sub 4}/MWCNTs sandwich buckypaper attached polymer composites are evidently improved. When the blending Fe{sub 3}O{sub 4} content in sandwich buckypaper is 20 wt%, the composite displays a larger and wider absorption peak (−12.62 dB at 17.72 GHz), and the

  9. Feasibility study of a SiC sandwich neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian, E-mail: caepwujian@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Lei, Jiarong, E-mail: jiarong_lei@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Jiang, Yong; Chen, Yu; Rong, Ru; Zou, Dehui; Fan, Xiaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Chen, Gang; Li, Li; Bai, Song [Nanjing Electronic Devices Institute, Nanjing 210016 (China)

    2013-04-21

    Semiconductor sandwich neutron spectrometers are suitable for in-pile measurements of fast reactor spectra thanks to their compact and relatively simple design. We have assembled and tested a sandwich neutron spectrometer based on 4H-silicon carbide (4H-SiC) Schottky diodes. The SiC diodes detect neutrons via neutron-induced charged particles (tritons and alpha particles) produced by {sup 6}Li(n,α){sup 3}H reaction. {sup 6}LiF neutron converter layers are deposited on the front surface of Schottky diodes by magnetron sputtering. The responses of SiC diodes to charged particles were investigated with an {sup 241}Am alpha source. A sandwich neutron spectrometer was assembled with two SiC Schottky diodes selected based on the charged-particle-response experimental results. The low-energy neutron response of the sandwich spectrometer was measured in the neutron field of the Chinese Fast Burst Reactor-II (CFBR-II). Spectra of alpha particles and tritons from {sup 6}Li(n,α){sup 3}H reaction were obtained with two well-resolved peaks. The energy resolution of the sum spectrum was 8.8%. The primary experimental results confirmed the 4H-SiC sandwich neutron spectrometer's feasibility. -- Highlights: ► Sandwich neutron spectrometer employing 4H-SiC as a detecting material has been developed for the first time. ► {sup 6}LiF neutron converter has been deposited on the surface of 4H-SiC Schottky diode. ► Preliminary testing results obtained with the 4H-SiC sandwich neutron spectrometer are presented.

  10. Development and evaluation of a DAS-ELISA for rapid detection of Tembusu virus using monoclonal antibodies against the envelope protein.

    Directory of Open Access Journals (Sweden)

    Hao Chen

    Full Text Available Since April 2010, Tembusu virus (TMUV which is a contagious pathogen of waterfowls, causing symptoms of high fever, loss of appetite and fall in egg production, has been reported in east of China. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA which detects for TMUV was developed, using two monoclonal antibodies (mAbs against the TMUV envelope (E protein. BALB/c mice were immunized with purified recombinant E protein expressed in E. coli. Three hybridoma cell lines designated as 12B1, 10C6 and 2D2, were screened by cell fusion and indirect ELISA for their ability to recognize different linear epitopes on the E protein, and were characterized subsequently. High-affinity mAbs 12B1 and 2D2 were used as capture and detection antibodies, respectively. The reaction conditions for the DAS-ELISA were optimized for TMUV detection. The cross-reactivity of the DAS-ELISA was determined using TMUV, duck plague virus, avian influenza virus subtype H9, Newcastle disease virus, duck hepatitis A virus type 1 and duck reovirus samples. A total of 191 homogenized tissues of field samples were simultaneously detected by DAS-ELISA and by RT-PCR. The former was found to have a high specificity of 99.1% and a sensitivity of 93.1%. These results reveal a positive coincidence between DAS-ELISA and RT-PCR at a coincidence rate of 95.8%. The method developed in this study can be used for the diagnosis of TMUV infection of duck origin.

  11. Plastic enzyme-linked immunosorbent assays (ELISA)-on-a-chip biosensor for botulinum neurotoxin A.

    Science.gov (United States)

    Han, Seung-Mok; Cho, Joung-Hwan; Cho, Il-Hoon; Paek, Eui-Hwan; Oh, Hee-Bok; Kim, Bong-Su; Ryu, Chunsun; Lee, Kyunghee; Kim, Young-Kee; Paek, Se-Hwan

    2007-03-21

    A plastic ELISA-on-a-chip (EOC) employing the concept of cross-flow immuno-chromatographic analysis was applied to the measurement of botulinum neurotoxin A (BoNT/A) as agent for bio-terrorism. Two monoclonal antibodies specific to the heavy chain of the toxin were raised and identified to form sandwich binding complexes as the pair with the analyte. For the construction of an immuno-strip, one was utilized as the capture antibody immobilized onto nitrocellulose membrane and the other as the detection coupled to an enzyme, horseradish peroxidase. The two plates of EOC used in this study were fabricated by injection molding of polycarbonate to improve the reproducibility of manufacture and, after inclusion of the immuno-strip, bonded using a UV-sensitive adhesive. Under optimal conditions of analysis, the chip produced a color signal in proportion to the analyte dose and the signal was quantified using a detector equipped with a digital camera. From the dose-response curve, the detection limit of BoNT/A was 2.0 ng mL(-1), approximately five times more sensitive than a commercial-version detection kit employing colloidal gold tracer.

  12. A comparison of ELISA, FAST-ELISA and gel diffusion tests for detecting antibody to equine infectious anaemia virus.

    Science.gov (United States)

    Lew, A M; Thomas, L M; Huntington, P J

    1993-01-01

    Sera of sixteen horses with clinical signs of EIA from six different outbreaks and sera of 100 uninfected horses were used to validate an ELISA for EIA diagnosis. The antigen used was a recombinant protein derived from the amino-terminal portion of the transmembrane envelope protein of EIA (gp45). Reactivity between positive and negative sera could be clearly distinguished. Comparison with the traditional agar gel immunodiffusion test (commonly called the Coggins test) showed that the ELISA was superior in sensitivity. Comparison of this ELISA with the FAST-ELISA system showed that the latter was less sensitive. Although the FAST-ELISA was much faster to perform, it could not be recommended as a diagnostic test in its present form, because the margin between reactivity by a positive serum and a negative serum was not high.

  13. Enhanced sandwich immunoassay using antibody-functionalized magnetic iron-oxide nanoparticles for extraction and detection of soluble transferrin receptor on a photonic crystal biosensor.

    Science.gov (United States)

    Peterson, Ross D; Chen, Weili; Cunningham, Brian T; Andrade, Juan E

    2015-12-15

    Iron deficiency anemia (IDA) has detrimental effects on individuals and societies worldwide. A standard sandwich assay (SA) for the detection of soluble transferrin receptor (sTfR), a biomarker of IDA, on a photonic crystal (PC) biosensor was established, but it was susceptible to non-specific signals from complex matrixes. In this study, iron-oxide nanoparticles (fAb-IONs) were used as magnetic immuno-probes to bind sTfR and minimize non-specific signals, while enhancing detection on the PC biosensor. This inverse sandwich assay (IA) method completely bound sTfR with low variability (detection in sera (Liquichek™ control sera) on the PC biosensor using two certified ELISAs as reference methods. A linear dose-response curve was elicited at the fAb-IONs concentration in which the theoretical binding ratio (sTfR:fAb-IONs) was calculated to be 0.05) at 14 and 21 μg/mL, respectively. The inherent imprecision of the IA and reference ELISAs was σ(δ)=0.45 µg/mL and the mean biases for Liquichek™ 1, 2 and 3 were 0.18, 0.19 and -0.04 µg/mL, respectively. Whereas the inherent imprecision of the SA and reference ELISAs was σ(δ)=0.52 µg/mL and the biases for Liquichek™ 1, 2 and 3 were 0.66, 0.14 and -0.67 µg/mL, respectively. Thus, unlike the SA, the IA method measures sTfR with the same bias as the reference ELISAs. Combined magnetic separation and detection of nutrition biomarkers on PC biosensors represents a facile method for their accurate and reliable quantification in complex matrixes.

  14. Analysis of fenbendazole residues in bovine milk by ELISA.

    Science.gov (United States)

    Brandon, David L; Bates, Anne H; Binder, Ronald G; Montague, William C; Whitehand, Linda C; Barker, Steven A

    2002-10-09

    Fenbendazole residues in bovine milk were analyzed by ELISAs using two monoclonal antibodies. One monoclonal antibody (MAb 587) bound the major benzimidazole anthelmintic drugs, including fenbendazole, oxfendazole, and fenbendazole sulfone. The other (MAb 591) was more specific for fenbendazole, with 13% cross-reactivity with the sulfone and no significant binding to the sulfoxide metabolite. The limit of detection of the ELISA method in the milk matrix was 7 ppb for MAb 587 and 3 ppb for MAb 591. Fenbendazole was administered in feed, drench, and paste form to three groups of dairy cattle. Milk was collected immediately before dosing and then every 12 h for 5 days. The ELISA indicated that residue levels varied widely among individual cows in each group. Fenbendazole levels peaked at approximately 12-24 h and declined rapidly thereafter. Metabolites were detected at much higher levels than the parent compound, peaked at approximately 24-36 h, and declined gradually. Residue levels were undetectable by 72 h. The ELISA data correlated well with the total residues determined by chromatographic analysis, but the use of the two separate ELISAs did not afford an advantage over ELISA with the single, broadly reactive MAb 587. The ELISA method could be used to flag high-residue samples in on-site monitoring of fenbendazole in milk and is a potential tool for studying drug pharmacokinetics.

  15. Plasmonic ELISA for the ultrasensitive detection of Treponema pallidum.

    Science.gov (United States)

    Nie, Xin-Min; Huang, Rong; Dong, Cai-Xia; Tang, Li-Juan; Gui, Rong; Jiang, Jian-Hui

    2014-08-15

    In this report, we have developed a plasmonic ELISA strategy for the detection of syphilis. Plasmonic ELISA is an enzyme-linked immunoassay combined with enzyme-mediated surface plasmon resonance (SPR) of gold nanoparticles (AuNPs). Immune response of the Treponema pallidum (T. pallidum) antibodies triggers the acetylcholinesterase-catalyzed hydrolysis of acetylthiocholine to produce abundant thiocholine. The positive charged thiol, in turn, alters the surface charge distribution the AuNPs and leads to the agglomeration of the AuNPs. The induced strong localized SPR effect of the agglomerate AuNPs can, thus, allow the quantitative assay of T. pallidum antibodies due to the remarkable color and absorption spectral response changes of the reaction system. The plasmonic ELISA exhibited a quasilinear response to the logarithmic T. pallidum antibody concentrations in the range of 1pg/mL-10ng/mL with a detection limit of 0.98pg/mL. Such a low detection limit was 1000-fold improvements in sensitivity over a conventional ELISA. The results of plasmonic ELISA in syphilis assays of serum specimens from 60 patients agreed with those obtained using a conventional ELISA method. The plasmonic ELISA has characteristics (analyte specific, cost-effective, ease of automatic, low limit of detection) that provide potential for diagnosis and therapeutic monitoring of syphilis.

  16. Enhancing Fatigue Performance of Sandwich Composites with Nanophased Core

    Directory of Open Access Journals (Sweden)

    S. Zainuddin

    2010-01-01

    Full Text Available We report fatigue performance of sandwich composites with nanophased core under shear load. Nanophased core was made from polyurethane foam dispersed with carbon nanofiber (CNF. CNFs were dispersed into part-A of liquid polyurethane through a sonication process and the loading of nanoparticles was 1.0 wt%. After dispersion, part-A was mixed with part-B, cast into a mold, and allowed to cure. Nanophased foam was then used to fabricate sandwich composites. Static shear tests revealed that strength and modulus of nanophased foams were 33% and 19% higher than those of unreinforced (neat foams. Next, shear fatigue tests were conducted at a frequency of 3 Hz and stress ratio (R of 0.1. S-N curves were generated and fatigue performances were compared. Number of cycles to failure for nanophased sandwich was significantly higher than that of the neat ones. For example, at 57% of ultimate shear strength, nanophased sandwich would survive 400,000 cycles more than its neat counterpart. SEM micrographs indicated stronger cell structures with nanophased foams. These stronger cells strengthened the sub-interface zones underneath the actual core-skin interface. High toughness of the sub-interface layer delayed initiation of fatigue cracks and thereby increased the fatigue life of nanophased sandwich composites.

  17. Critical velocity of sandwich cylindrical shell under moving internal pressure

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Critical velocity of an infinite long sandwich shell under moving internal pres-sure is studied using the sandwich shell theory and elastodynamics theory. Propagation of axisymmetric free harmonic waves in the sandwich shell is studied using the sandwich shell theory by considering compressibility and transverse shear deformation of the core, and transverse shear deformation of face sheets. Based on the elastodynamics theory, displacement components expanded by Legendre polynomials, and position-dependent elastic constants and densities are introduced into the equations of motion. Critical ve-locity is the minimum phase velocity on the desperation relation curve obtained by using the two methods. Numerical examples and the finite element (FE) simulations are pre-sented. The results show that the two critical velocities agree well with each other, and two desperation relation curves agree well with each other when the wave number κ is relatively small. However, two limit phase velocities approach to the shear wave velocities of the face sheet and the core respectively when k limits to infinite. The two methods are efficient in the investigation of wave propagation in a sandwich cylindrical shell when κ is relatively small. The critical velocity predicted in the FE simulations agrees with theoretical prediction.

  18. Experimental study on mechanical properties of aircraft honeycomb sandwich structures

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available Mechanical behaviour of sandwich panels under different conditions have been exprimentally studied in this research to increase the knowledge of aircraft sandwich panel structures and facilitate design criteria for aircraft structures. Tests were concentrated on the honeycomb sandwich structures under different loads including flexural, insert shear, flat wise tension and compression loads. Furthermore, effect of core density and face material on mechanical behavior of different samples were investigated and compared with analytical and FEM method. Effects of skin thickness on strength of honycomb sandwhich panels under shear pull out and moments have also been considerd in this study. According to this investigation, insert strength and flexural test under different load conditions is strongly affected by face thickness, but compression and tearoff (falt wise tensile properties of a sandwich panel depends on core material. The study concludes that the correlation between experimental results and the analytical predictions will enable the designer to predict the mechanical behaviour and strength of a sandwich beam; however, applied formula may lead engineers to unreliable results for shear modulus.

  19. A comparison of FRP-sandwich penetrating impact test methods

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrand, M. [VTT Manufacturing Technology, Espoo (Finland). Maritime and Mechanical Engineering

    1996-12-31

    The main objective of this project is to identify the test methods which provide useful results for the different types of penetrating impacts occurring in sandwich structures. A series of penetrating impact tests on FRP-sandwich panels is performed using three different test methods and the results of the test methods are compared. The test methods used are the standardised method ISO 6603 and two non-standardised methods. The first non-standardised method uses a pyramid-shaped impactor instead of the cylindrical impactor used in the ISO 6603 method. In the second non-standardised method, the impact test is performed quasistatically using a cylindrical impactor. Possible stages of failure occurring in FRP-sandwich during a penetrating impact are illustrated. A comprehensive test method should be able to provoke various failure modes, as observed in impact failures of actual sandwich structures. The results obtained with the three test methods lead to a different ranking in impact strength of the panels. Hence, impact test results obtained with different test methods are not even qualitatively comparable. The pyramid-shaped impactor is able to generate clearly more failure modes than the cylindrical impactor in the ISO 6603 method. Therefore, it is considered to be of more practical value for determining the impact strength of PRP-sandwich structures. (orig.) (15 refs.)

  20. Thermal buckling analysis of truss-core sandwich plates

    Institute of Scientific and Technical Information of China (English)

    陈继伟; 刘咏泉; 刘伟; 苏先樾

    2013-01-01

    Truss-core sandwich plates have received much attention in virtue of the high values of strength-to-weight and stiffness-to-weight as well as the great ability of impulse-resistance recently. It is necessary to study the stability of sandwich panels under the influence of the thermal load. However, the sandwich plates are such complex three-dimensional (3D) systems that direct analytical solutions do not exist, and the finite element method (FEM) cannot represent the relationship between structural parameters and mechanical properties well. In this paper, an equivalent homogeneous continuous plate is idealized by obtaining the effective bending and transverse shear stiffness based on the characteristics of periodically distributed unit cells. The first order shear deformation theory for plates is used to derive the stability equation. The buckling temperature of a simply supported sandwich plate is given and verified by the FEM. The effect of related parameters on mechanical properties is investigated. The geometric parameters of the unit cell are optimized to attain the maximum buckling temperature. It is shown that the optimized sandwich plate can improve the resistance to thermal buckling significantly.

  1. Design of sandwich acoustic window for sonar domes

    Institute of Scientific and Technical Information of China (English)

    YU Mengsa; LI Dongsheng; GONG Li; XU Jian

    2005-01-01

    Aimed at the low noise design of sonar dome in ships, a method has been presented for calculating the sonar self noise of a simplified sonar dome consisting of sandwich acoustic window and parallel acoustic cavity, which is excited by stationary random pressure fluctuation of turbulence boundary layer, using temporal and spatial double Fourier transform and wavenumber-frequency spectrum analysis. After numerically analyzing the influence of geometrical and physical parameters of acoustic window on the sonar self noise, the design method and reasonable parameters for sandwich acoustic window are proposed. The results show that the property of low noise induced by acoustic window of sandwich is dominated by the cut-off effect of longitudinal wave and transverse wave propagating in the visco-elastic layer of sandwich as well as the mismatch effect of impedance. If the thickness, density, Young's modulus and damping factor of plates and visco-elastic layer as well as the sound speed of longitudinal wave and transverse wave in the visco-elastic layer are selected reasonably, the maximum noise reduction of sandwich acoustic window is 6.5 dB greater than that of a single glass fiber reinforced plastic plate.

  2. Evaluation of an ELISA for the diagnosis of brucellosis.

    Science.gov (United States)

    Mathai, E; Singhal, A; Verghese, S; D'Lima, D; Mathai, D; Ganesh, A; Thomas, K; Moses, P

    1996-06-01

    Brucela serology using ELISA and standard agglutination test was performed on 23 patients with prolonged fever where the test was requested, on 26 randomly chosen patients with prolonged fever where it was not requested and on 17 controls. ELISA was positive in 39.1, 26.9 and 0 per cent respectively in these groups. Brucellosis may often be unsuspected because of its varied clinical manifestations and may be a more important cause of fever than previously considered. Our data reaffirm that ELISA is superior to the standard agglutination test for the diagnosis of brucellosis.

  3. Signal Amplification in Field Effect-Based Sandwich Enzyme-Linked Immunosensing by Tuned Buffer Concentration with Ionic Strength Adjuster.

    Science.gov (United States)

    Kumar, Satyendra; Kumar, Narendra; Panda, Siddhartha

    2016-04-01

    Miniaturization of the sandwich enzyme-based immunosensor has several advantages but could result in lower signal strength due to lower enzyme loading. Hence, technologies for amplification of the signal are needed. Signal amplification in a field effect-based electrochemical immunosensor utilizing chip-based ELISA is presented in this work. First, the molarities of phosphate buffer saline (PBS) and concentrations of KCl as ionic strength adjuster were optimized to maximize the GOx glucose-based enzymatic reactions in a beaker for signal amplification measured by change in the voltage shift with an EIS device (using 20 μl of solution) and validated with a commercial pH meter (using 3 ml of solution). The PBS molarity of 100 μM with 25 mM KCl provided the maximum voltage shift. These optimized buffer conditions were further verified for GOx immobilized on silicon chips, and similar trends with decreased PBS molarity were obtained; however, the voltage shift values obtained on chip reaction were lower as compared to the reactions occurring in the beaker. The decreased voltage shift with immobilized enzyme on chip could be attributed to the increased Km (Michaelis-Menten constant) values in the immobilized GOx. Finally, a more than sixfold signal enhancement (from 8 to 47 mV) for the chip-based sandwich immunoassay was obtained by altering the PBS molarity from 10 to 100 μM with 25 mM KCl.

  4. The effect of sandwiched Ag in the wall of TiO{sub 2} nanotube on the photo-catalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Liu Zhaohui [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Chen Jinzhu [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhang Yuyuan; Wu Liangpeng [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Xinjun, E-mail: lixj@ms.giec.ac.cn [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2011-07-15

    Highlights: {yields} TiO{sub 2} nanotube with the wall sandwiched by Ag was prepared. {yields} The sandwiched nanotube structure exhibits enhanced photo-catalytic performance. {yields} Improved photoelectrochemical performance is due to effective charge separation. - Abstract: TiO{sub 2} nanotube was synthesized by a hydrothermal process using TiO{sub 2} nanoparticle as starting material, and then it was loaded with Ag through a silver mirror reaction. Further, the Ag loading TiO{sub 2} nanotube was decorated by TiO{sub 2} via TiCl{sub 4} hydrolysis to obtain the TiO{sub 2} nanotube with the wall sandwiched by Ag. The TiO{sub 2} nanotubes were characterized by transmission electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and UV-vis spectrophotometer. The electrochemical impedance spectroscopy and transient photocurrent were investigated in a three-electrode system with the TiO{sub 2} nanotube films served as photoanodes. The photo-catalytic activity was evaluated by photo-degradation of methyl orange under UV light irradiation. The results show that the sandwiched Ag could inhibit the crystal phase transformation of TiO{sub 2} nanotube from anatase to rutile. And the sandwiched nanotube structure exhibits enhanced photo-catalytic performance due to the efficient separation of the photo-generated carriers.

  5. Assessing hazelnut allergens by protein- and DNA-based approaches: LC-MS/MS, ELISA and real-time PCR.

    Science.gov (United States)

    Costa, Joana; Ansari, Parisa; Mafra, Isabel; Oliveira, M Beatriz P P; Baumgartner, Sabine

    2014-04-01

    Hazelnut (Corylus avellana L.) is responsible for a significant part of the allergies related to nuts. Still, it is a very much appreciated nut and as consequence is widely used in all types of processed foods, such as chocolates. Correct food labelling is currently the most effective means of preventing the consumption of allergenic ingredients, namely hazelnut, by the sensitised/allergic individuals. Thus, to verify labelling compliance and to ensure allergic patient protection, the development of highly sensitive methodologies is of extreme importance. In this study, three major methodologies, namely enzyme-linked immunosorbent assays (ELISA), liquid chromatography coupled with mass spectrometry and real-time polymerase chain reaction, were evaluated for their performance regarding the detection of hazelnut allergens in model chocolates. The sandwich ELISA and respective antibodies were in-house developed and produced. With sensitivity levels of approximately 1 mg kg(-1) and limits of quantification of 50-100 mg kg(-1), all the performed methods were considered appropriate for the identification of hazelnut in complex foods such as chocolates. To our knowledge, this was the first successful attempt to develop and compare three independent approaches for the detection of allergens in foods.

  6. Ham Sandwich with Mayo: A Stronger Conclusion to the Classical Ham Sandwich Theorem

    CERN Document Server

    Elton, John H

    2009-01-01

    The conclusion of the classical ham sandwich theorem of Banach and Steinhaus may be strengthened: there always exists a common bisecting hyperplane that touches each of the sets, that is, intersects the closure of each set. Hence, if the knife is smeared with mayonnaise, a cut can always be made so that it will not only simultaneously bisect each of the ingredients, but it will also spread mayonnaise on each. A discrete analog of this theorem says that n finite nonempty sets in n-dimensional Euclidean space can always be simultaneously bisected by a single hyperplane that contains at least one point in each set. More generally, for n compactly-supported positive finite Borel measures in Euclidean n-space, there is always a hyperplane that bisects each of the measures and intersects the support of each measure.

  7. Indirect enzyme-antibody sandwich enzyme-linked immunosorbent assay for quantification of TAXI and XIP type xylanase inhibitors in wheat and other cereals.

    Science.gov (United States)

    Beaugrand, Johnny; Gebruers, Kurt; Ververken, Cedric; Fierens, Ellen; Dornez, Emmie; Goddeeris, Bruno M; Delcour, Jan A; Courtin, Christophe M

    2007-09-19

    To quantify Triticum aestivum xylanase inhibitor (TAXI) and xylanase inhibiting protein (XIP) type proteins in cereals in general and wheat ( T. aestivum) in particular, a robust enzyme-linked immunosorbent assay (ELISA) using an uncommon enzyme-antibody sandwich format was developed. Bacillus subtilis glycoside hydrolase family (GH) 11 and Aspergillus oryzae GH 10 xylanases were selected for coating ELISA plate wells to capture TAXI and XIP, respectively, prior to probing with antibodies. The detection threshold of the developed ELISA was much lower than that of the currently used xylanase inhibitor assay and the recently described Western blot approach. Because of its broad dynamic range (TAXI, 30-600 ng/mL, and XIP, 3-60 ng/mL), one proper standard extract dilution can be used for analyzing different wheat varieties, whereas for the currently used colorimetric assay, often different dilutions need to be analyzed. The TAXI ELISA for wheat was successfully adapted for barley ( Hordeum vulgare) and could also be used for other cereals.

  8. Comparison of dot-ELISA and standard ELISA for detection of Neisseria meningitidis outer membrane complex-specific antibodies

    Directory of Open Access Journals (Sweden)

    Elza FT Belo

    2010-02-01

    Full Text Available Dot-ELISA using the outer membrane complex antigens of Neisseria meningitidis as a target was standardized for rapid detection of meningococcal-specific antibodies in human serum. We investigated the level of meningococcal-specific IgG, IgA, and IgM in serum using dot-ELISA with outer membrane antigens prepared from Neisseria meningitidis serotype B:4.19:P1.15,3,7,9 (a strain isolated from a Brazilian epidemic. The dot-ELISA is based on the same principles as the standard ELISA and is useful for detection of anti-N. meningitidis B antibodies in serum of patients with meningococcal infections. For the assay, outer membrane complexes (OMCs were absorbed by nitrocellulose membrane and blocked with a 5% skim milk solution. Serum samples were drawn upon hospital admission and during convalescence from patients with meningococcal septicemia, and single samples were drawn from uninfected controls. We retrospectively examined a total of 57 serum samples: 35 from patients infected with N. meningitidis B, 12 from patients infected with Haemophilus influenzae b, and 10 from health individuals. When performed at room temperature, dot-ELISA took approximately four hours to perform, and the optimum antigen concentration was 0.42 µg per dot. The specificity of IgG, IgM, and IgA demonstrates that dot-ELISA using OMCs from N. meningitidis B as a target is suitable for serologic verification of clinically suspected meningococcal disease in patients and for titer determination of antibodies produced during different phases of natural infection. Furthermore, the sensitivity of dot-ELISA was comparable to that of standard ELISA. Overall, dot-ELISA is simple to perform, rapid, and low cost. Further validation of the test as a screening tool is required.

  9. Comparison of dot-ELISA and standard ELISA for detection of Neisseria meningitidis outer membrane complex-specific antibodies.

    Science.gov (United States)

    Belo, Elza Ft; Farhat, Calil K; Gaspari, Elizabeth N De

    2010-01-01

    Dot-ELISA using the outer membrane complex antigens of Neisseria meningitidis as a target was standardized for rapid detection of meningococcal-specific antibodies in human serum. We investigated the level of meningococcal-specific IgG, IgA, and IgM in serum using dot-ELISA with outer membrane antigens prepared from Neisseria meningitidis serotype B:4.19:P1.15,3,7,9 (a strain isolated from a Brazilian epidemic). The dot-ELISA is based on the same principles as the standard ELISA and is useful for detection of anti-N. meningitidis B antibodies in serum of patients with meningococcal infections. For the assay, outer membrane complexes (OMCs) were absorbed by nitrocellulose membrane and blocked with a 5% skim milk solution. Serum samples were drawn upon hospital admission and during convalescence from patients with meningococcal septicemia, and single samples were drawn from uninfected controls. We retrospectively examined a total of 57 serum samples: 35 from patients infected with N. meningitidis B, 12 from patients infected with Haemophilus influenzae b, and 10 from health individuals. When performed at room temperature, dot-ELISA took approximately four hours to perform, and the optimum antigen concentration was 0.42 microg per dot. The specificity of IgG, IgM, and IgA demonstrates that dot-ELISA using OMCs from N. meningitidis B as a target is suitable for serologic verification of clinically suspected meningococcal disease in patients and for titer determination of antibodies produced during different phases of natural infection. Furthermore, the sensitivity of dot-ELISA was comparable to that of standard ELISA. Overall, dot-ELISA is simple to perform, rapid, and low cost. Further validation of the test as a screening tool is required.

  10. Comparison of dot-ELISA and standard ELISA for detection of Neisseria meningitidis outer membrane complex-specific antibodies

    Directory of Open Access Journals (Sweden)

    Elza FT Belo

    Full Text Available Dot-ELISA using the outer membrane complex antigens of Neisseria meningitidis as a target was standardized for rapid detection of meningococcal-specific antibodies in human serum. We investigated the level of meningococcal-specific IgG, IgA, and IgM in serum using dot-ELISA with outer membrane antigens prepared from Neisseria meningitidis serotype B:4.19:P1.15,3,7,9 (a strain isolated from a Brazilian epidemic. The dot-ELISA is based on the same principles as the standard ELISA and is useful for detection of anti-N. meningitidis B antibodies in serum of patients with meningococcal infections. For the assay, outer membrane complexes (OMCs were absorbed by nitrocellulose membrane and blocked with a 5% skim milk solution. Serum samples were drawn upon hospital admission and during convalescence from patients with meningococcal septicemia, and single samples were drawn from uninfected controls. We retrospectively examined a total of 57 serum samples: 35 from patients infected with N. meningitidis B, 12 from patients infected with Haemophilus influenzae b, and 10 from health individuals. When performed at room temperature, dot-ELISA took approximately four hours to perform, and the optimum antigen concentration was 0.42 µg per dot. The specificity of IgG, IgM, and IgA demonstrates that dot-ELISA using OMCs from N. meningitidis B as a target is suitable for serologic verification of clinically suspected meningococcal disease in patients and for titer determination of antibodies produced during different phases of natural infection. Furthermore, the sensitivity of dot-ELISA was comparable to that of standard ELISA. Overall, dot-ELISA is simple to perform, rapid, and low cost. Further validation of the test as a screening tool is required.

  11. 1/3 SUBHARMONIC SOLUTION OF ELLIPTICAL SANDWICH PLATES

    Institute of Scientific and Technical Information of China (English)

    李银山; 张年梅; 杨桂通

    2003-01-01

    The problem of nonlinear forced oscillations for elliptical sandwich plates is dealtwith. Based on the governing equations expressed in terms of five displacement components,the nonlinear dynamic equation of an elliptical sandwich plate under a harmonic force isderived. A superpositive-iterative harmonic balance ( SIHB ) method is presented for thesteady-state analysis of strongly nonlinear oscillators. In a periodic oscillation, the periodicsolutions can be expressed in the form of basic harmonics and bifurcate harmonics. Thus,an oscillation system which is described as a second order ordinary differential equation,can be expressed as fundamental differential equation with fundamental harmonics andincremental differential equation with derived harmonics. The 1/3 subharnonic solution ofan elliptical sandwich plate is investigated by using the methods of SIHB. The SIHB methodis compared with the numerical integration method. Finally, asymptotical stability of the1/3 subharmonic oscillations is inspected.

  12. Identification of material properties of sandwich structure with piezoelectric patches

    Directory of Open Access Journals (Sweden)

    Zemčík R.

    2008-11-01

    Full Text Available The work focuses on light-weight sandwich structures made of carbon-epoxy skins and foam core which have unique bending stiffness compared to conventional materials. The skins are manufactured by vacuum autoclave technology from unidirectional prepregs and the sandwich is then glued together. The resulting material properties of the structure usually differ from those provided by manufacturer or even those obtained from experimental tests on separate materials, which makes computational models unreliable. Therefore, the properties are identified using the combination of experimental analysis of the sandwich with attached piezoelectric transducer and corresponding static and modal finite element analyses. Simple mathematical optimization with repetitive finite element solution is used. The model is then verified by transient analysis when the piezoelectric patch is excited by harmonic signals covering the first two eigen-frequencies and the induced oscillations are measured by laser sensor.

  13. Microtomography with sandwich detectors for small-animal bone imaging

    Science.gov (United States)

    Kim, S. H.; Kim, D. W.; Kim, D.; Youn, H.; Cho, S.; Kim, H. K.

    2016-10-01

    An x-ray radiographic system consisting of two detectors in tandem, or a sandwich detector, can produce dual-energy image from a single-shot exposure. Subtraction of two images obtained from the two detectors can produce a sharper image through an unsharp masking effect if the two images are formed at different spatial resolutions. This is indeed possible by incorporating different thicknesses of x-ray conversion layers in the detectors. In this study, we have developed a microtomography system with a sandwich detector in pursuit of high-resolution bone-enhanced small-animal imaging. The results show that the bone-enhanced images reconstructed from the dual-energy projection data provide higher visibility of bone details than the conventionally reconstructed images. The microtomography with the single-shot dual-energy sandwich detector will be useful for the high-resolution bone-enhanced small-animal imaging.

  14. Free vibration Analysis of Sandwich Plates with cutout

    Science.gov (United States)

    Mishra, N.; Basa, B.; Sarangi, S. K.

    2016-09-01

    This paper presents the free vibration analysis of sandwich plates with cutouts. Cutouts are inevitable in structural applications and the presence of these cutouts in the structures greatly influences their dynamic characteristics. A finite element model has been developed here using the ANSYS 15.0 software to study the free vibration characteristics of sandwich plates in the presence of cutouts. Shell 281 element, an 8-noded element with six degrees of freedom suited for analyzing thin to moderately thick structures is considered in the development of the model. Block Lanczose method is adopted to extract the mode shapes to obtain the natural frequency corresponding to free vibration of the plate. The effects of parametric variation on the natural frequency of the sandwich plates with cutout are studied and results are presented.

  15. Enhanced Performance of Sandwich Structures by Improved Damage Tolerance

    DEFF Research Database (Denmark)

    Martakos, Georgios

    The PhD thesis investigates the enhancement of the damage tolerance of sandwich structures by the embedding of a new type of core inserts that act as face/core interface crack stopping elements. The thesis presents series of experimental investigations where the new crack stopping elements...... are embedded in both sandwich beam and panel specimens. The experimental observations form the basis for evaluating the efficiency of the proposed crack stopping inserts. For the experiments, Digital Image Correlation (DIC) was used to characterize the measure the local strain fields and overall deformation...... behaviour around the new crack stopper elements. In support for the experimental investigations, a Finite Element (FE) analysis based methodology, including fracture mechanics analysis and the so-called ‘cycle jump’ technique, was developed to predict the progression of damage in sandwich specimens...

  16. ANALISIS KERAGAAN PANEL SANDWICH UNTUK RUMAH PRA-PABRIKASI

    Directory of Open Access Journals (Sweden)

    Naresworo Nugroho

    2010-12-01

    Full Text Available In the last five years, several earthquakes struck several places in Indonesia and thousands of people died caused of their masonry house. Therefore, the idea of bamboo utilization in the form of structural sandwich panel components for anti-seismic pre-fabrication house is one of appropriate way out. This research describes the performance and behavior of engineered structure wooden-bamboo sandwich panel in full sized test. The wall frame being use were meranti wood, this frame attached by plywood as face and back, then 5 cm bamboo cutting as core; the fastener used in this study were isocyanate resin and nails. This study carried out by experimental data of full scale structural tests on shear wall (ISO 22452. These result showed that the seismic reliability of the wall frame system made of bamboo sandwich panel was appropriate and will be useful for pre-fabrication houses as anti-seismic and environment friendly residential building

  17. Study on voids of epoxy matrix composites sandwich structure parts

    Science.gov (United States)

    He, Simin; Wen, Youyi; Yu, Wenjun; Liu, Hong; Yue, Cheng; Bao, Jing

    2017-03-01

    Void is the most common tiny defect of composite materials. Porosity is closely related to composite structure property. The voids forming behaviour in the composites sandwich structural parts with the carbon fiber reinforced epoxy resin skins was researched by adjusting the manufacturing process parameters. The composites laminate with different porosities were prepared with the different process parameter. The ultrasonic non-destructive measurement method for the porosity was developed and verified through microscopic examination. The analysis results show that compaction pressure during the manufacturing process had influence on the porosity in the laminate area. Increasing the compaction pressure and compaction time will reduce the porosity of the laminates. The bond-line between honeycomb core and carbon fiber reinforced epoxy resin skins were also analyzed through microscopic examination. The mechanical properties of sandwich structure composites were studied. The optimization process parameters and porosity ultrasonic measurement method for composites sandwich structure have been applied to the production of the composite parts.

  18. Examination of Sandwich Materials Using Air-Coupled Ultrasonics

    DEFF Research Database (Denmark)

    Borum, K.K.; Berggreen, Carl Christian

    2004-01-01

    The air-coupled ultrasonic techniques have been improved drastically in recent years. Better equipment has made this technique much more useful. This paper focuses on the examination of sandwich materials used in naval ships. It is more convenient to be able to make the measurements directly...... in atmospheric air instead of using immersion technique. The air-coupled techniques have been used in through-transmission mode using separate sender and receiver transducer. The frequency was either 50 kHz or 120 kHz. Laboratory tests on glass fibre/PVC foam core sandwich panels showed that debonds between core...... and skin laminate could be found by the air-coupled technique. It was therefore decided to use this technique in-situ during mechanical testing of sandwich panels. These tests were done in order to verify a developed FEM code using interfacial fracture mechanics and illustrated on a superstructure...

  19. Effect of layer length on deflection in sandwich beams

    Science.gov (United States)

    Abbu, Muthanna A.; AL-Ameri, Riyadh

    2017-09-01

    A theoretical study has been carried out on sandwich beams strengthened mechanically by two external steel plates attached to their tension and compression sides with so-called "shear connectors ". This study is based on the individual behaviour of each component of the composite sandwich section (i.e. reinforced concrete beam and upper steel plate and lower steel plate). The approach has been developed to simulate the behaviour of such beams, and is based on neglecting the separation between the three layers; i.e., the deflections are equal in each element through the same section. The differential equations reached were solved analytically. Deflection was calculated by using the approach for several beams, tested in two series, and close agreements were obtained with the experimental values. Furthermore, the interaction efficiency between the three elements in a composite sandwich beam has been considered thoroughly, from which the effect of some parameters, such as plate length upon the behaviour of such beams, were studied.

  20. Vibration analysis and optimization of sandwich composite with curvilinear fibers

    Science.gov (United States)

    Honda, S.; Narita, Y.

    2016-09-01

    The present paper develops a shell element based on the refined zigzag theory (RZT) and applies it to the vibration analysis and optimization problem of the composite sandwich plate composed of CFRP skins and soft-cores. The RZT accepts large differences in layer stiffness, and requires less calculation effort than the layer-wise or three-dimensional theories. Numerical results revealed that the present method predicts vibration characteristics of composite sandwich plates with soft-core accurately. Then, shapes of reinforcing fibers in CFRP composite skins are optimized to maximize fundamental frequencies. As an optimizer, the particle swarm optimization (PSO) approach is employed since curvilinear fiber shapes are defined by continuous design variables. Obtained results showed that the composite sandwich with optimum curvilinear fiber shapes indicates higher fundamental frequencies compared with straight fibers.

  1. ['Sandwich PhD': considerations for a successful experience abroad].

    Science.gov (United States)

    Salvetti, Marina de Goes; Bueno, Mariana; Gastaldo, Denise; Kimura, Amélia Fumiko; Pimenta, Cibele Andrucioli de Mattos

    2013-03-01

    International PhD internship, named "Sandwich PhD" in Brazil is an opportunity to improve research abilities, to become known in academic area and to establish and/or increase work opportunities in an international context. In this article, we describe key factors regarding the planning and development of the "Sandwich PhD" as experienced by professors and students involved in the collaboration between the School of Nursing, University of São Paulo and Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Canada. We also present the participation of PhD students' network as an alternative to the "Sandwich PhD". An international experience, when well-planned and developed correctly, promotes students' personal and professional development and favors the internationalization of Brazilian graduate programs and research groups.

  2. Extended high order sandwich panel theory for bending analysis of sandwich beams with carbon nanotube reinforced face sheets

    Science.gov (United States)

    Jedari Salami, S.

    2016-02-01

    Bending analysis of a sandwich beam with soft core and carbon nanotube reinforced composite (CNTRC) face sheets in the literature is presented based on Extended High order Sandwich Panel Theory (EHSAPT). Distribution of fibers through the thickness of the face sheets could be uniform or functionally graded (FG). In this theory the face sheets follow the first order shear deformation theory (FSDT). Besides, the two dimensional elasticity is used for the core. The field equations are derived via the Ritz based solution which is suitable for any essential boundary condition. The influences of boundary conditions on bending response of the sandwich panel with soft core and CNTRC face sheet are investigated. In each type of boundary condition the effect of distribution pattern of CNTRCs on many essential involved parameters of the sandwich beam with functionally graded carbon nanotube reinforced composite (FG- CNTRC) face sheets are studied in detail. Finally, experimental result have been compared with those obtained based on developed solution method. It is concluded that, the sandwich beam with X distribution figure of face sheets is the strongest with the smallest transverse displacement, and followed by the UD, O and ∧-ones, respectively.

  3. Amperometric Detection of Bacillus anthracis Spores: A Portable, Low-Cost Approach to the ELISA

    Directory of Open Access Journals (Sweden)

    Gabriel D. Peckham

    2013-01-01

    Full Text Available Antibody-based detection assays are generally robust, a desirable characteristic for in-the-field use. However, to quantify the colorimetric or fluorescent signal, these assays require expensive and fragile instruments which are ill-suited to in-the-field use. Lateral flow devices (LFDs circumvent these barriers to portability but suffer from poor sensitivity and subjective interpretation. Here, an antibody-based method for detecting Bacillus anthracis spores via amperometric signal generation is compared to ELISA and LFDs. This amperometric immunoassay uses antibody conjugated to magnetic beads and glucose oxidase (GOX along with the electron mediator 2, 6-dichlorophenolindophenol (DCPIP for production of a measurable current from a 0.4 V bias voltage. With similar sensitivity to ELISA, the assay can be completed in about 75 minutes while being completely powered and operated from a laptop computer. Immunoassay amperometry holds promise for bringing low-cost, quantitative detection of hazardous agents to the field.

  4. Comparative study of circulating immune complexes quantity detection by three assays--CIF-ELISA, C1q-ELISA and anti-C3 ELISA.

    Science.gov (United States)

    Stanilova, S A; Slavov, E S

    2001-07-01

    The assessment of the soluble immune complexes (IC) in human sera is traditionally performed by the C1q binding assay. In the present study, a novel method for the quantity of immune complexes was reported. The methodology was based on measuring their deposition on solid-phase C3 binding glycoprotein (CIF), using an enzyme-linked immunosorbent assay. We also used ELISA that employed anti-C3 antibodies to determined the quantity of immune complexes. The three assays were evaluated for their performance characteristics on the same specially prepared samples: 55 normal sera, 99 sera from RA, 88 sera from SLE, and 27 sera from PSS. The results were compared by reference to a common standard-heat aggregated IgG that possesses many activities of immune complexes. Three of the tests used displayed almost the same specificity (over 95%), while their relative sensitivity varied depending on the disease sera tested. The sensitivity of the assays used was recorded highest for C1q ELISA-28.97% of positive sera, followed by CIF-ELISA-19.63% and lowest for anti-C3 ELISA-17.29%. A well-expressed correlation was found between CIF-ELISA and anti-C3 ELISA data (r=0.42), and a week correlation was noted when comparing CIF-ELISA and C1q ELISA IC levels detected (r=0.28). When the correlation coefficients were calculated individually for each disease category, they were clearly different, and that reflected indirectly in different sensitivities of the test for various disease categories. We also found that the results from the simultaneous performance of the tests demonstrated low percentage positive results when three or two assays were used. This is most probably due to the different assay abilities to detect IC with different sizes and composition, which shows that a small part of IC in the tested sera can be detected simultaneously by more than one assay. On the basis of the results obtained, we concluded that optimal screening for IC could be achieved by parallel application of

  5. Serotype assignment by sero-agglutination, ELISA, and PCR

    Science.gov (United States)

    For assessing isolates of Listeria monocytogenes serotype designation is the foremost subtyping method used. Traditionally serotyping has been done with agglutination reactions. In the last decade alternative serotyping methods were described using Enzyme Linked Immunosorbent Assay(ELISA)and Polymer...

  6. Ultrasensitive ELISA using enzyme-loaded nanospherical brushes as labels.

    Science.gov (United States)

    Qu, Zhenyuan; Xu, Hong; Xu, Ping; Chen, Kaimin; Mu, Rong; Fu, Jianping; Gu, Hongchen

    2014-10-01

    Improving the detection sensitivity of enzyme-linked immunosorbent assay (ELISA) is of utmost importance for meeting the demand of early disease diagnosis. Herein we report an ultrasensitive ELISA system using horseradish peroxidase (HRP)-loaded nanospherical poly(acrylic acid) brushes (SPAABs) as labels. HRP was covalently immobilized in SPAABs with high capacity and activity via an efficient "chemical conjugation after electrostatic entrapment" (CCEE) process, thus endowing SPAABs with high amplification capability as labels. The periphery of SPAAB-HRP was further utilized to bind a layer of antibody with high density for efficient capture of analytes owing to the three-dimensional architecture of SPAABs. Using human chorionic gonadotrophin (hCG) as a model analyte, the SPAAB-amplified system drastically boosted the detection limit of ELISA to 0.012 mIU mL(-1), a 267-fold improvement as compared to conventional ELISA systems.

  7. The difference of ELISA and LABScreen in detecting HLA antibodies

    Institute of Scientific and Technical Information of China (English)

    吴萍萍

    2013-01-01

    Objective To compare the difference of ELISA and LABScreen in detecting HLA antibodies and evaluate their effects on allograft rejection.Methods Consecutive patients undergoing kidney transplantion from November,2008 to December,2009 in the First Affiliated Hospital

  8. Screening methods in alveolar echinococcosis: a follow-up study comparing Emc- and Emf-ELISA with Em2plus-ELISA and ultrasonography.

    Science.gov (United States)

    Hänle, M M; Banzhaf, H-M; Forsbach-Birk, V; Kirch, A; Akinli, A S; Mason, R A; Reuter, S; Kratzer, W

    2009-01-01

    The purpose of the present study was to identify Echinococcus multilocularis infection in follow-up of 95 subjects initially seropostive by Emc-ELISA or Emf-ELISA antibody assays and to compare the utility of these assays with specific Em2plus-ELISA and ultrasound screening for E. multilocularis infection. At follow-up seven subjects were seropositive with both methods, while three were seropositive only with Emc-ELISA and 11 only with Emf-ELISA. All subjects were seronegative with Em2plus-ELISA. There were no manifestations of E. multilocularis infestation by ultrasonographic screening. Seropositivity on Emc-ELISA and Emf-ELISA screening tests does not appear to correlate with manifest alveolar echinococcosis identified by ultrasound. A recommendation for further follow-up of subjects found to be seropositive with Emc-ELISA and Emf-ELISA but with no sonographic evidence of disease is not justified at this time.

  9. Methods for Using Durable Adhesively Bonded Joints for Sandwich Structures

    Science.gov (United States)

    Smeltzer, Stanley S., III (Inventor); Lundgren, Eric C. (Inventor)

    2016-01-01

    Systems, methods, and apparatus for increasing durability of adhesively bonded joints in a sandwich structure. Such systems, methods, and apparatus includes an first face sheet and an second face sheet as well as an insert structure, the insert structure having a first insert face sheet, a second insert face sheet, and an insert core material. In addition, sandwich core material is arranged between the first face sheet and the second face sheet. A primary bondline may be coupled to the face sheet(s) and the splice. Further, systems, methods, and apparatus of the present disclosure advantageously reduce the load, provide a redundant path, reduce structural fatigue, and/or increase fatigue life.

  10. NONLINEAR VIBRATION OF CIRCULAR SANDWICH PLATES UNDER CIRCUMJACENT LOAD

    Institute of Scientific and Technical Information of China (English)

    DU Guo-jun; MA Jian-qing

    2006-01-01

    Based on yon Karman plate theory, the issue about nonlinear vibration for circular sandwich plates under circumjacent load with the loosely clamped boundary condition was researched. Nonlinear differential eigenvalue equations and boundary conditions of the problem were formulated by variational method and then their exact static solution can be got. The solution was derived by modified iteration method, so the anslytic relations between amplitude and nonlinear oscillating frequency for circular sandwich plates were obtained. When circumjacent load makes the lowest natural frequency zero,critical load is obtained.

  11. A New Silicon-Based Ferroelectric Sandwich Structure

    Institute of Scientific and Technical Information of China (English)

    任天令; 张林涛; 刘理天; 李志坚

    2001-01-01

    A new silicon-based PbTiO3/Pb(Zr0.53 Ti0.47)O3/PbTiO3 sandwich structure is fabricated by a sol-gel method. Compared with other fabrication processes without PbTiO3 buffer layers, the annealing temperature is greatly reduced by as much as 100℃. Capacitance-voltage, polarization-electric field and dielectric-frequency properties of this sandwich structure are studied. The Pb(Zrx Ti1-x)O3 films are proved to have good dielectric and ferroelectric properties.

  12. New-sandwiched hydrogen separation membranes with low environmental impact

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Ozaki, T.; Komaki, M.; Nishimura, C. [Eco-Energy Materials Group, Ecomaterials Center, Ibaraki (Japan)

    2003-07-01

    There is a strong interest in economical methods for hydrogen separation. In this work, we have developed sandwiched membranes, Pd-Ag/V-15Ni/Pd-Ag, which had much lower environmental impact than palladium-based membranes, which are the most commonly used membrane for the current production of highly pure hydrogen. The Pd-Ag overlayer was prepared on V-15Ni substrates (thickness 40 {mu}m) using multi-target sputtering. The hydrogen permeation of the Pd-Ag/V-15Ni/Pd-Ag sandwiched membranes was examined using gas permeation technology. (orig.)

  13. Friction stir welding (FSW of aluminium foam sandwich panels

    Directory of Open Access Journals (Sweden)

    M. Bušić

    2016-07-01

    Full Text Available The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and flexural strength for three-point bending test have been determined for samples taken from the welded joints. Results have confirmed anticipated effects of independent variables.

  14. Buckling analysis of sandwich plate using layer wise theory

    Energy Technology Data Exchange (ETDEWEB)

    Ranjbaran, Arash; Khoshravan, Mohammad Reza [University of Tabriz, Tabriz (Iran, Islamic Republic of); Kharazi, Mahsa [Sahand University of Technology, Sahand (Iran, Islamic Republic of)

    2014-07-15

    Buckling analysis of sandwich plate was investigated using layer wise method. The formulation was based on the first-order shear deformation theory, and the Rayleigh-Ritz method was used for approximating and determining the displacement field. The results obtained from layer wise theory was compared with finite element results and showed good agreement. This study demonstrated that layer wise theory could describe buckling behavior of sandwich plates with high accuracy and represents a more realistic and acceptable description of behavior of the plates with much less computational cost.

  15. Damage assessment of compression loaded debond damaged sandwich panels

    DEFF Research Database (Denmark)

    Moslemian, Ramin; Berggreen, Christian; Quispitupa, Amilcar;

    2010-01-01

    Sandwich composites with face sheets of fiber-reinforced plastics (FRP) and cores of polymer foam offer a lightweight construction that is well suited to wind turbine blades, naval and other vessels for high-speed operation or where payload considerations require that the structural weight...... with an implanted circular face/core debond. Compression tests were conducted on intact sandwich panels and panels with an implanted circular face/core debond with three different types of foam core materials (PVC H130, PVC H250 and PMI 51-IG). The strains and out-of-plane displacements of the debonded region were...

  16. Fabrication and characterization of sandwiched optical fibers with periodic gratings.

    Science.gov (United States)

    Chiang, Chia-Chin

    2010-08-01

    This study proposes a novel process for fabricating a sandwiched long-period fiber grating (SLPFG) using a SU-8 thick photoresist technique. The SLPFG consists of a thin cladding optical fiber sandwiched with a double-sided periodical grating coating. By varying the external loads on the SLPFG, the transmission dip of the resonance wavelength is tuned according to a squared-harmonic curve. The SLPFG can thus be utilized as a loss tunable filter or sensor. The resonance dip wavelength is related to the cladding thicknesses of the optical fiber and the periods of the grating. A maximum transmission resonant dip of 34.61dB was achieved.

  17. ELISA for brucellosis detection based on three Brucella recombinant proteins.

    Science.gov (United States)

    Thepsuriyanont, Pikun; Intarapuk, Apiradee; Chanket, Panita; Tunyong, Wittawat; Kalambaheti, Thareerat

    2014-01-01

    Control of brucellosis among farm animals, wildlife and humans require reliable diagnosis. Rose Bengal serological test (RBT) is based on lipopolysaccharide antigen of Brucella, which may cross react with other gram-negative bacteria and produce false positive result. Immunoreactive proteins, such as outer-membrane protein BP26, ribosome recycling factor protein CP24 and Brucella lumazine synthase (BLS), previously reported to be recognized by infected sheep sera, were selected for production of recombinant proteins for use in an ELISA in order to investigate immune response among goats and cows, in comparison with commercial RBT. Cut-off value for ELISA was based on the immune response of in vitro fertilized goats and cows. Goats positive for Brucella culture or by RBT were ELISA positive for either IgG or IgM against at least one recombinant protein. For animals with negative RBT, animals with positive ELISA could be detected, and 61.6% possessed ELISA values as high as in infected animals. Thus, this ELISA procedure is proposed as an alternative to RBT for screening of brucellosis in farm animals.

  18. Ligand-induced haptotropic rearrangements in bis(indenyl)zirconium sandwich complexes.

    Science.gov (United States)

    Bradley, Christopher A; Lobkovsky, Emil; Keresztes, Ivan; Chirik, Paul J

    2005-07-27

    Addition of principally sigma-donating ligands such as THF, chelating diethers, or 1,2-bis(dimethyl)phosphinoethane to eta(9),eta(5)-bis(indenyl)zirconium sandwich complexes, (eta(9)-C(9)H(5)-1,3-R(2))(eta(5)-C(9)H(5)-1,3-R(2))Zr (R = alkyl or silyl), induces haptotropic rearrangement to afford (eta(6)-C(9)H(5)-1,3-R(2))(eta(5)-C(9)H(5)-1,3-R(2))ZrL adducts. Examples where L = THF and DME have been characterized by X-ray diffraction and revealed significant buckling of the eta(6) benzo ring, consistent with reduction of the arene, and highlight the importance of the zirconium(IV) canonical form. For the THF-induced haptotropic rearrangements, the thermodynamic driving force for ring migration has been measured as a function of indenyl substituent and demonstrates silylated sandwiches favor THF coordination and the eta(6),eta(5) bonding motif over their alkylated counterparts. In the case of chelating diethers, measurement of the corresponding equilibrium constants establish more stable eta(6),eta(5) adducts with five- over four-membered chelates and with smaller oxygen and carbon backbone substituents. Kinetic studies on both THF and DME addition to (eta(9)-C(9)H(5)-1,3-(SiMe(3))(2))(eta(5)-C(9)H(5)-1,3-(SiMe(3))(2))Zr established a first-order dependence on the incoming ligand, consistent with a mechanism involving direct attack of the incoming nucleophile on the eta(9),eta(5) sandwich. These results further highlight the ability of the indenyl ligand to smoothly adjust hapticity to meet the electronic requirements of the metal center.

  19. Metallic magneto-electronic materials and its expectations

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The basic characters, properties and possible applications of magneto-electronic materials with metal lic sandwich structure have been introduced. The expectation of its further development has been conjectured.

  20. Comparisons of SHM Sensor Models with Empirical Test Data for Sandwich Composite Structures

    Science.gov (United States)

    2011-09-01

    propagation in a honeycomb sandwich panel was done by Metis Design Inc. in collaboration with ARC NASA . The sandwich panel fabricated for this test...structures. Sandwich type composites are being studied for use in NASAs new heavy lift launch vehicle and flaw detection is crucial for safety and for...and at the Marshall Space Flight Center to examine acoustic wave propagating and the ability to detect intrinsic faults in sandwich type composite

  1. Nanoscale quantification of charge injection and transportation process in Si-nanocrystal based sandwiched structure.

    Science.gov (United States)

    Xu, Jie; Xu, Jun; Zhang, Pengzhan; Li, Wei; Chen, Kunji

    2013-10-21

    Si nanocrystals are formed by using KrF pulsed laser crystallization of an amorphous SiC/ultrathin amorphous Si/amorphous SiC sandwiched structure. Electrons and holes are injected into Si nanocrystals via a biased conductive AFM tip and the carrier decay and transportation behaviours at the nanoscale are studied by joint characterization techniques of Kelvin probe force microscopy (KPFM) and conductive atomic force microscopy (CAFM). Quantification of the surface charge density is realized by solving the Poisson equation based on KPFM measurements. Besides, the asymmetric barrier height for electrons and holes is considered to play a dominant role in controlling the charge retention and transportation characteristics. The methodology developed in this work is promising for studying the charge injection and transportation process in other materials and structures at the nanoscale.

  2. An ELISA test for the detection of antibodies to Legionella pneumophila.

    OpenAIRE

    Wreghitt, T. G.; Nagington, J.; Gray, J

    1982-01-01

    An enzyme-linked immunosorbent assay (ELISA) test has been developed to detect antibodies to Legionella pneumophila serogroup 1. There is good correlation between indirect fluorescent antibody (IFA) and ELISA titres but ELISA is more sensitive.

  3. Stabilization of nonlinear sandwich systems via state feedback-Discrete-time systems

    NARCIS (Netherlands)

    Wang, Xu; Stoorvogel, Anton A.; Saberi, Ali; Grip, H°avard Fjær; Sannuti, Peddapullaiah

    2011-01-01

    A recent paper (IEEE Trans. Aut. Contr. 2010; 55(9):2156–2160) considered stabilization of a class of continuous-time nonlinear sandwich systems via state feedback. This paper is a discrete-time counterpart of it. The class of nonlinear sandwich systems consists of saturation elements sandwiched bet

  4. A modified DCB sandwich specimen for measuring mixed-mode cohesive laws

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Sørensen, Bent F.; Berggreen, Christian;

    2008-01-01

    A test method is described for measuring cohesive laws for interfaces in sandwich structures. It is proposed to increase the bending stiffness of the sandwich faces by adhering steel bars onto the sandwich faces. This stiffening reduces rotations and ensures that the method is applicable for thin...... which mixed-mode cohesive laws are extracted....

  5. Intrant ELISA: A Novel Approach to Fabrication of Electrospun Fiber Mat-Assisted Biosensor Platforms and Their Integration within Standard Analytical Well Plates

    Directory of Open Access Journals (Sweden)

    Samira Hosseini

    2016-11-01

    Full Text Available A combination of far-field electrospinning (FFES and free-radical polymerization has been used to fabricate coated electrospun polymer fiber mats as a new type of biosensor platform. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV electrospun fibers were dip-coated with different compositions of poly methyl methacrylate-co-methacrylic acid (poly(MMA-co-MAA. This synergistic approach utilizes large specific surface area of PHBV fibers and co-polymer coatings that feature an optimum concentration of surface carboxyl (–COOH groups. The platform surface morphology, porosity and tunable hydrophobicity enhance biomolecular interactions via plurality of molecular forces. These customized fiber mats have been integrated into a newly designed 96-well plate called an “intrant enzyme-linked immunosorbent assay” or i-ELISA. I-ELISA allows colorimetric sandwich assay to be carried out without any modifications or additional steps in ELISA methodology. By introducing the fiber mats in fabrication of i-ELISA via extensions on the lid, we address some of the limitations of the previous designs while demonstrating an enhanced signal intensity up to 12 times higher than that of conventional assays. With improved sensitivity, specificity and accuracy in the detection of dengue virus, i-ELISA has proven to be a reliable platform for biomolecular recognition. The proposed fiber mat-assisted well plate in this study holds great potential as a universal approach for integration of different types of fiber mats with pre-designed specific properties in order to enhance the detection sensitivity of the assay.

  6. Stiff, Strong Splice For A Composite Sandwich Structure

    Science.gov (United States)

    Schmaling, D.

    1991-01-01

    New type of splice for composite sandwich structure reduces peak shear stress in structure. Layers of alternating fiber orientation interposed between thin ears in adhesive joint. Developed for structural joint in spar of helicopter rotor blade, increases precision of control over thickness of adhesive at joint. Joint easy to make, requires no additional pieces, and adds little weight.

  7. Bending and Deformation of Sandwich Panels Due to Localized Pressure

    Directory of Open Access Journals (Sweden)

    Bambang K. Hadi

    2005-05-01

    Full Text Available Bending and deformation of sandwich panels due to localized pressure were analyzed using both Rayleigh-Ritz and finite element methods. The faces were made of laminated composite plates, while the core was a honeycomb material. Carbon fiber and glass fiber reinforced plastics were used for composite plate faces. In the case of Rayleigh-Ritz method, first the total energy of the system was calculated and then taking the variations of the total energy, the sandwich panel deflections could be computed. The deflections were assumed by means of Fourier series. A finite element code NASTRAN was exploited extensively in the finite element method. 3-dimensional 8-node brick elements were used to model sandwich panels, for both the faces sheets and the core. The results were then compared to each other and in general they are in good agreements. Dimple phenomena were found in these cases. It shows that localized pressure on sandwich structures will produce dimple on the pressurize region with little effects on the rest of the structures.

  8. Mechanical Behavior of CFRP Lattice Core Sandwich Bolted Corner Joints

    Science.gov (United States)

    Zhu, Xiaolei; Liu, Yang; Wang, Yana; Lu, Xiaofeng; Zhu, Lingxue

    2017-02-01

    The lattice core sandwich structures have drawn more attention for the integration of load capacity and multifunctional applications. However, the connection of carbon fibers reinforced polymer composite (CFRP) lattice core sandwich structure hinders its application. In this paper, a typical connection of two lattice core sandwich panels, named as corner joint or L-joint, was investigated by experiment and finite element method (FEM). The mechanical behavior and failure mode of the corner joints were discussed. The results showed that the main deformation pattern and failure mode of the lattice core sandwich bolted corner joints structure were the deformation of metal connector and indentation of the face sheet in the bolt holes. The metal connectors played an important role in bolted corner joints structure. In order to save the calculation resource, a continuum model of pyramid lattice core was used to replace the exact structure. The computation results were consistent with experiment, and the maximum error was 19%. The FEM demonstrated the deflection process of the bolted corner joints structure visually. So the simplified FEM can be used for further analysis of the bolted corner joints structure in engineering.

  9. Elastic-plastic deformation of sandwich rod on elastic basis

    Institute of Scientific and Technical Information of China (English)

    GU Yu

    2008-01-01

    Sandwich composite material possesses advantages of both light weight and high strength.Although the mechanical behaviors of sandwich composite material with the influence of single external environment have been intensively studied,little work has been done in the study of mechanical property,in view of the nonlinear behavior of sandwich composites in the complicated external environments.In this paper,the problem about the bending of the three-layer elastic-plastic rod located on the elastic base,with a compressibly physical nonlinear core,has been studied.The mechanical response of the designed three-layer elements consisting of two bearing layers and a core has been examined.The complicated problem about curving of the three-layer rod located on the elastic base has been solved.The convergence of the proposed method of elastic solutions is examined to convince that the solution is acceptable.The calculated results indicate that the plasticity and physical nonlinearity of materials have a great influence on the deformation of the sandwich rod on the elastic basis.

  10. Editorial: Sandwiched Between Strasbourg and Karlsruhe: EU Fundamental Rights Protection

    NARCIS (Netherlands)

    Reestman, J.H.; Besselink, L.

    2016-01-01

    Starting out from the notion of the `Verfassungsgerichtsverbund´, coined by the President Vosskuhle of the German Federal Constitutional Court, this contribution sketches the manner in which the European Court of Justice operates, sandwiched in between the European Court of Human Rights that sets a

  11. Electrowetting-driven oscillating drops sandwiched between two substrates

    NARCIS (Netherlands)

    Mampallil, Dileep; Eral, H.B.; Staicu, A.D.; Mugele, F.; Ende, van den D.

    2013-01-01

    Drops sandwiched between two substrates are often found in lab-on-chip devices based on digital microfluidics. We excite azimuthal oscillations of such drops by periodically modulating the contact line via ac electrowetting. By tuning the frequency of the applied voltage, several shape modes can be

  12. Dielectrophoretic behaviours of microdroplet sandwiched between LN substrates.

    Science.gov (United States)

    Chen, Lipin; Li, Shaobei; Fan, Bolin; Yan, Wenbo; Wang, Donghui; Shi, Lihong; Chen, Hongjian; Ban, Dechao; Sun, Shihao

    2016-07-07

    We demonstrate a sandwich configuration for microfluidic manipulation in LiNbO3 platform based on photovoltaic effect, and the behaviours of dielectric microdroplet under this sandwich configuration are investigated. It is found that the microdroplet can generate in the form of liquid bridge inside the LiNbO3-based sandwich structure under the governing dielectrophoretic force, and the dynamic process of microdroplet generation highly depends on the substrate combinations. Dynamic features found for different combinations are explained by the different electrostatic field distribution basing on the finite-element simulation results. Moreover, the electrostatic field required by the microdroplet generation is estimated through meniscus evolution and it is found in good agreement with the simulated electrostatic field inside the sandwich gap. Several kinds of microdroplet manipulations are attempted in this work. We suggest that the local dielectrophoretic force acting on the microdroplet depends on the distribution of the accumulated irradiation dosage. Without using any additional pumping or jetting actuator, the microdroplet can be step-moved, deformed or patterned by the inconsecutive dot-irradiation scheme, as well as elastically stretched out and back or smoothly guided in a designed pass by the consecutive line-irradiation scheme.

  13. Application of Load Carrying Sandwich Elements in Wind Turbine Blades

    DEFF Research Database (Denmark)

    Jensen, Jacob Fisker; Schultz, Jacob Pagh; Berggreen, Carl Christian

    2005-01-01

    . For a single skin design, buckling is critical compared to other design criterions. By introducing sandwich, a significant weight reduction and increased buckling capacity is obtained. Tower clearance now becomes critical. Proper choice of core material and thickness is important to prevent face wrinkling...

  14. Effect of Physical Nonlinearity on Local Buckling in Sandwich Beams

    NARCIS (Netherlands)

    Koissin, Vitaly; Shipsha, Andrey; Skvortsov, Vitaly

    2010-01-01

    This article deals with experimental, theoretical, and FE characterization of the local buckling in foam-core sandwich beams. In the theoretical approach, this phenomena is considered in a periodic formulation (unbounded wrinkle wave); a nonlinear stress—strain response of the face material is accou

  15. Damage Tolerance of Sandwich Plates With Debonded Face Sheets

    Science.gov (United States)

    Sankar, Bhavani V.

    2001-01-01

    A nonlinear finite element analysis was performed to simulate axial compression of sandwich beams with debonded face sheets. The load - end-shortening diagrams were generated for a variety of specimens used in a previous experimental study. The energy release rate at the crack tip was computed using the J-integral, and plotted as a function of the load. A detailed stress analysis was performed and the critical stresses in the face sheet and the core were computed. The core was also modeled as an isotropic elastic-perfectly plastic material and a nonlinear post buckling analysis was performed. A Graeco-Latin factorial plan was used to study the effects of debond length, face sheet and core thicknesses, and core density on the load carrying capacity of the sandwich composite. It has been found that a linear buckling analysis is inadequate in determining the maximum load a debonded sandwich beam can carry. A nonlinear post-buckling analysis combined with an elastoplastic model of the core is required to predict the compression behavior of debonded sandwich beams.

  16. Bending moment of galvanized iron glass fiber sandwich panel

    Directory of Open Access Journals (Sweden)

    Gurustal Somnath Swamy

    2016-05-01

    Full Text Available The main objective of this project is to prepare a laminated with Galvanized iron thickness fractions, fiber volume fractions and orientation in the layers of GF were fabricated by hand lay-up method and evaluated for their bending moment properties of the sandwich panel using universal testing machine. This paper theoretically calculates the bending behavior of sandwich panel. The recent need to develop a new range of materials has resulted in the development of high performance lightweight composites with excellent properties. Metal– composite systems consist of alternating layers of metal and fiber-reinforced polymer composites which are bonded by an adhesive. Sandwich beams were tested under Air Bending. Stress-strain and stress-displacement were recorded by using AIMIL UTM. The beam face sheets exhibited a softening non-linearity on the bending side. Experimental results were in good agreement with predictions from simple models. On an overall basis, the sandwich panel exhibited better bending moment performance than the monolithic galvanized iron

  17. The elastic response of sandwich structures to local loading

    NARCIS (Netherlands)

    Koysin, V.; Skvortsov, Vitaly; Krahmalev, Sergey; Shipsha, Andrey

    2004-01-01

    The paper addresses the elastic response of sandwich panels to local static and dynamic loading. The bottom face is assumed to be clamped, so that the overall bending is eliminated. The governing equations are derived using the static Lamé equations for the core and the thin plate Kirchoff–Love

  18. Multiscale Finite-Element Modeling of Sandwich Honeycomb Composite Structures

    Directory of Open Access Journals (Sweden)

    Yu. I. Dimitrienko

    2014-01-01

    Full Text Available The paper presents a developed multi-scale model of sandwich honeycomb structures. The model allows us both to calculate effective elastic-strength characteristics of honeycomb and forced covering of sandwich, and to find a 3D stress-strain state of structures using the threedimensional elastic theory for non- homogeneous media. On the basis of finite element analysis it is shown, that under four-point bending the maximal value of bending and shear stresses in the sandwich honeycomb structures are realized in the zone of applied force and plate support. Here the local stress maxima approximately 2-3 times exceed the “engineering” theoretical plate values of bending and shear stresses in the middle of panel. It is established that at tests for fourpoint bending there is a failure of the honeycomb sandwich panels because of the local adhesion failure rather than because of the covering exfoliation off the honeycomb core in the middle of panel.

  19. Fatigue failure of sandwich beams with face sheet wrinkle defects

    DEFF Research Database (Denmark)

    Leong, Martin Klitgaard; Hvejsel, C.F.; Thomsen, Ole Thybo

    2012-01-01

    This paper presents experimental fatigue results for GFRP face sheet/balsa core sandwich beams with face sheet wrinkle defects, subjected to fully reversed in-plane fatigue loading. An estimate of the fatigue design limit is presented, based on static test results, finite element analyses...

  20. Dielectrophoretic behaviours of microdroplet sandwiched between LN substrates

    Science.gov (United States)

    Chen, Lipin; Li, Shaobei; Fan, Bolin; Yan, Wenbo; Wang, Donghui; Shi, Lihong; Chen, Hongjian; Ban, Dechao; Sun, Shihao

    2016-07-01

    We demonstrate a sandwich configuration for microfluidic manipulation in LiNbO3 platform based on photovoltaic effect, and the behaviours of dielectric microdroplet under this sandwich configuration are investigated. It is found that the microdroplet can generate in the form of liquid bridge inside the LiNbO3-based sandwich structure under the governing dielectrophoretic force, and the dynamic process of microdroplet generation highly depends on the substrate combinations. Dynamic features found for different combinations are explained by the different electrostatic field distribution basing on the finite-element simulation results. Moreover, the electrostatic field required by the microdroplet generation is estimated through meniscus evolution and it is found in good agreement with the simulated electrostatic field inside the sandwich gap. Several kinds of microdroplet manipulations are attempted in this work. We suggest that the local dielectrophoretic force acting on the microdroplet depends on the distribution of the accumulated irradiation dosage. Without using any additional pumping or jetting actuator, the microdroplet can be step-moved, deformed or patterned by the inconsecutive dot-irradiation scheme, as well as elastically stretched out and back or smoothly guided in a designed pass by the consecutive line-irradiation scheme.

  1. Low-Velocity Impact on Composite Sandwich Plates

    Science.gov (United States)

    1996-07-01

    plate and correct for this error. 3.4 One- and Two-Degree of Freedom Models A single degree of freedom system (figure 3-3a) was used by Caprino et al...Composite Materials, Vol. 26, No. 10: 1523-1535 (1992). 211) Caprino , G., and Teti, R. "Impact and post-impact behavior of foam core sandwich

  2. Fluid Structure Interaction Effect on Sandwich Composite Structures

    Science.gov (United States)

    2011-09-01

    14. SUBJECT TERMS Fluid Structure Interaction, FSI, composite, balsa, low velocity impact, sandwich composites, VARTM , Vacuum Assisted Resin Transfer...11 1. Vacuum Assisted Resin Transfer Molding ( VARTM ) ...................11 2. Procedure...required equipment for VARTM composite production. ..............10 Figure 4. VARTM Lay-up (From [8

  3. Effect of microencapsulated phase change material in sandwich panels

    Energy Technology Data Exchange (ETDEWEB)

    Castellon, Cecilia; Medrano, Marc; Roca, Joan; Cabeza, Luisa F. [GREA Innovacio Concurrent, Edifici CREA, Universitat de Lleida, Pere de Cabrera s/n, 25001 Lleida (Spain); Navarro, Maria E.; Fernandez, Ana I. [Departamento de Ciencias de los Materiales e Ingenieria Metalurgica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Lazaro, Ana; Zalba, Belen [Instituto de Investigacion en Ingenieria de Aragon, I3A, Grupo de Ingenieria Termica y Sistemas Energeticos (GITSE), Dpto. Ingenieria Mecanica, Area de Maquinas y Motores Termicos, Universidad de Zaragoza, Campus Politecnico Rio Ebro, Edificio ' ' Agustin de Betancourt,' ' Maria de Luna s/n, 50018 Zaragoza (Spain)

    2010-10-15

    Sandwich panels are a good option as building materials, as they offer excellent characteristics in a modular system. The goal of this study was to demonstrate the feasibility of using the microencapsulated PCM (Micronal BASF) in sandwich panels to increase their thermal inertia and to reduce the energy demand of the final buildings. In this paper, to manufacture the sandwich panel with microencapsulated PCM three different methods were tested. In case 1, the PCM was added mixing the microencapsulated PCM with one of the components of the polyurethane. In the other two cases, the PCM was added either a step before (case 2) or a step after (case 3) to the addition of the polyurethane to the metal sheets. The results show that in case 1 the effect of PCM was overlapped by a possible increase in thermal conductivity, but an increase of thermal inertia was found in case 3. In case 2, different results were obtained due to the poor distribution of the PCM. Some samples showed the effect of the PCM (higher thermal inertia), and other samples results were similar to the conventional sandwich panel. In both cases (2 and 3), it is required to industrialize the process to improve the results. (author)

  4. Dynamic Behaviour of Concrete Sandwich Panel under Blast Loading

    Directory of Open Access Journals (Sweden)

    Dong Yongxiang

    2009-01-01

    Full Text Available Surface contact explosion experiments were performed to study the dynamic behaviour of concrete sandwich panel subjected to blast loading. Experimental results have shown that there are four damage modes explosion cratering, scabbing of the backside, radial cracking induced failure, and circumferential cracking induced failure. It also illustrates that different foam materials sandwiched in the multi-layered medium have an important effect on damage patterns. Due to the foam material, the stress peak decreases one order of magnitude and the duration is more than four times that of the panel without the soft layer by numerical simulation. Additionally, the multi layered medium with concrete foam demonstrates the favourable protective property compared with that of aluminum foam. Meanwhile, the optimal analysis of the thickness of the foam material in the sandwich panel was performed in terms of experimental and numerical analyseis. The proper thickness proportion of soft layer is about 20 percent to the total thickness of sandwich panel under the conditions in this study.Defence Science Journal, 2009, 59(1, pp.22-29, DOI:http://dx.doi.org/10.14429/dsj.59.1480  

  5. Methods for Assessing Honeycomb Sandwich Panel Wrinkling Failures

    Science.gov (United States)

    Zalewski, Bart F.; Dial, William B.; Bednarcyk, Brett A.

    2012-01-01

    Efficient closed-form methods for predicting the facesheet wrinkling failure mode in sandwich panels are assessed. Comparisons were made with finite element model predictions for facesheet wrinkling, and a validated closed-form method was implemented in the HyperSizer structure sizing software.

  6. Flexural Strength of Functionally Graded Nanotube Reinforced Sandwich Spherical Panel

    Science.gov (United States)

    Mahapatra, Trupti R.; Mehar, Kulmani; Panda, Subrata K.; Dewangan, S.; Dash, Sushmita

    2017-02-01

    The flexural behaviour of the functionally graded sandwich spherical panel under uniform thermal environment has been investigated in the present work. The face sheets of the sandwich structure are made by the functionally graded carbon nanotube reinforced material and the core face is made by the isotropic and homogeneous material. The material properties of both the fiber and matrix are assumed to be temperature dependent. The sandwich panel model is developed in the framework of the first order shear deformation theory and the governing equation of motion is derived using the variational principle. For the discretization purpose a suitable shell element has been employed from the ANSYS library and the responses are computed using a parametric design language (APDL) coding. The performance and accuracy of the developed model has been established through the convergence and validation by comparing the obtained results with previously published results. Finally, the influence of different geometrical parameters and material properties on the flexural behaviour of the sandwich spherical panel in thermal environment has been investigated through various numerical illustrations and discussed in details.

  7. Effect of Physical Nonlinearity on Local Buckling in Sandwich Beams

    NARCIS (Netherlands)

    Koysin, V.; Shipsha, Andrey; Skvortsov, Vitaly

    2010-01-01

    This article deals with experimental, theoretical, and FE characterization of the local buckling in foam-core sandwich beams. In the theoretical approach, this phenomena is considered in a periodic formulation (unbounded wrinkle wave); a nonlinear stress—strain response of the face material is accou

  8. Damage tolerance of a composite sandwich with interleaved foam core

    Science.gov (United States)

    Ishai, Ori; Hiel, Clement

    1992-01-01

    A composite sandwich panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades. Interleaving of the core with tough interlayers was done to prevent core cracking and to improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity drop-weight impacts as well as high velocity ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor cracking of the core. Residual compressive strength (RCS) of the skin, which was derived from flexural test, shows the expected trend of decreasing with increasing size of the damage, impact energy, and velocity. In the case of skin damage, RCS values of around 50 percent of the virgin interleaved reference were obtained at the upper impact energy range. Based on the similarity between low-velocity and ballistic-impact effects, it was concluded that impact energy is the main variable controlling damage and residual strength, where as velocity plays a minor role.

  9. Modular container assembled from fiber reinforced thermoplastic sandwich panels

    Science.gov (United States)

    Donnelly, Mathew William; Kasoff, William Andrew; Mcculloch, Patrick Carl; Williams, Frederick Truman

    2007-12-25

    An improved, load bearing, modular design container structure assembled from thermoformed FRTP sandwich panels in which is utilized the unique core-skin edge configuration of the present invention in consideration of improved load bearing performance, improved useful load volume, reduced manufacturing costs, structural weight savings, impact and damage tolerance and repair and replace issues.

  10. Flexural Behavior of Aluminum Honeycomb Core Sandwich Structure

    Science.gov (United States)

    Matta, Vidyasagar; Kumar, J. Suresh; Venkataraviteja, Duddu; Reddy, Guggulla Bharath Kumar

    2017-05-01

    This project is concerned with the fabrication and flexural testing of aluminium honey comb sandwich structure which is a special case of composite materials that is fabricated by attaching two thin but stiff skins to a light weight but thick core. The core material is normally low density material but its high thickness provide the sandwich composite with high bonding stiffness. Honeycomb core are classified into two types based on the materials and structures. Hexagonal shape has a unique properties i.e has more bonding strength and less formation time based on the cell size and sheet thickness. Sandwich structure exhibit different properties such as high load bearing capacity at low weight and has excellent thermal insulation. By considering the above properties it has tendency to minimize the structural problem. So honey comb sandwich structure is choosed. The core structure has a different applications such as aircraft, ship interiors, construction industries. As there is no proper research on strength characteristics of sandwich structure. So, we use light weight material to desire the strength. There are different parameters involved in this structure i.e cell size, sheet thickness and core height. In this project we considered 3 level of comparison among the 3 different parameters cell size of 4, 6 and 8 mm, sheet thickness of 0.3, 0.5 and 0.7 mm, and core height of 20,25 and 30 mm. In order to reduce the number of experiment we use taguchi design of experiment, and we select the L8 orthogonal array is the best array for this type of situation, which clearly identifies the parameters by independent of material weight to support this we add the minitab software, to identify the main effective plots and regression equation which involves the individual response and corresponding parameters. Aluminium material is used for the fabrication of Honeycomb sandwich structure among the various grades of aluminium we consider the AL6061 which is light weight material

  11. Sandwich-like graphene/polypyrrole/layered double hydroxide nanowires for high-performance supercapacitors

    Science.gov (United States)

    Li, Xuejin; Zhang, Yu; Xing, Wei; Li, Li; Xue, Qingzhong; Yan, Zifeng

    2016-11-01

    Electrode design in nanoscale is considered to be ultra-important to construct a superb capacitor. Herein, a sandwich-like composite was made by combining graphene/polypyrrole (GPPY) with nickel-aluminum layered double hydroxide nanowires (NiAl-NWs) via a facile hydrothermal method. This sandwich-like architecture is promising in energy storage applications due to three unique features: (1) the conductive GPPY substrate not only effectively prevents the layered double hydroxides species from aggregating, but also considerably facilitates the electron transmission; (2) the ultrathin NiAl-NWs ensure a maximum exposure of active Ni2+, which can improve the efficiency of rapid redox reactions even at high current densities; (3) the sufficient space between anisotropic NiAl-NWs can accommodate a large volume change of the nanowires to avoid their collapse or distortion during the reduplicative redox reactions. Keeping all these unique features in mind, when the as-prepared composite was applied to supercapacitors, it presented an enhanced capacitive performance in terms of high specific capacitance (845 F g-1), excellent rate performance (67% retained at 30 A g-1), remarkable cyclic stability (92% maintained after 5000 cycles) and large energy density (40.1 Wh·Kg-1). This accomplishment in the present work inspires an innovative strategy of nanoscale electrode design for high-rate performance supercapacitor electrodes containing pseuducapacitive metal oxide.

  12. Analysis of crack propagation in nuclear graphite using three-point bending of sandwiched specimens

    Energy Technology Data Exchange (ETDEWEB)

    Shi Li; Li Haiyan; Zou Zhenmin [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom); Fok, Alex S.L. [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)], E-mail: alex.fok@manchester.ac.uk; Marsden, Barry J. [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom); Hodgkins, Andrew; Mummery, Paul M.; Marrow, James [School of Materials, University of Manchester, Grosvenor St., Manchester M1 7HS (United Kingdom)

    2008-01-31

    The aim of this paper was to assess the suitability of the sandwiched beam in three-point bending as a technique for determining fracture toughness and R-curve behaviour of nuclear graphite using small beam specimens. Surface displacements of the cracked beam specimen were measured using Electronic Speckle Pattern Interferometry (ESPI) and Image Correlation in order to accurately monitor crack propagation and frictional contact between the test specimen and the sandwiching beams. The results confirmed that solutions based on the simple beam theory could overestimate the fracture toughness of graphite. Finite element analysis using a Continuum Damage Mechanics failure model indicated that both friction and shape of the notch played an important part in providing resistance to crack growth. Inclusion of these factors and the use of more accurate load vs. crack length curves derived from the FE model would provide a satisfactory measure of fracture toughness in small beam specimens under such a loading configuration. The particular graphite tested, IG-110, showed a decrease in fracture toughness with increasing crack length.

  13. Silica-sandwiched Au nanoparticle arrays by a soft PE-CVD/RF sputtering approach

    Energy Technology Data Exchange (ETDEWEB)

    Barreca, Davide [ISTM-CNR and INSTM, Department of Chemistry, Padova University, Via Marzolo, 1-35131 Padova (Italy); Gasparotto, Alberto; Maccato, Chiara; Tondello, Eugenio [Department of Chemistry, Padova University and INSTM, Via Marzolo, 1-35131 Padova (Italy)], E-mail: alberto.gasparotto@unipd.it

    2008-06-25

    This work is focused on the development of an innovative synthetic route to SiO{sub 2}-sandwiched Au nanoparticle arrays. The adopted strategy consists of: (i) the radio frequency sputtering of gold on thermally oxidized Si(100) and silica substrates from Ar plasmas; (ii) the plasma enhanced chemical vapor deposition of a SiO{sub 2} overlayer using tetramethoxysilane as precursor from Ar-O{sub 2} plasmas. A common feature of both preparative stages is the use of very soft processing conditions at temperatures close to room temperature, in order to tailor the Au nanoparticle morphology and to preserve it upon SiO{sub 2} coverage. In situ monitoring of gold deposition was accomplished by means of laser reflection interferometry. Valuable information on the system morphology before and after SiO{sub 2} coverage was provided by field emission-scanning electron microscopy for samples with different Au content. Additional important information on the system chemical composition, structure and optical response was gained by the combined use of x-ray photoelectron spectroscopy, glancing incidence x-ray diffraction and UV-visible absorption spectroscopy. The results obtained highlight the formation of high-purity SiO{sub 2}/Au/SiO{sub 2}-sandwiched stacks, in which the gold content and distribution, as well as the nanoparticle morphology, could be tailored by the sole variation of the sputtering time, without any further ex situ treatment.

  14. Characterization of dermal plates from armored catfish Pterygoplichthys pardalis reveals sandwich-like nanocomposite structure.

    Science.gov (United States)

    Ebenstein, Donna; Calderon, Carlos; Troncoso, Omar P; Torres, Fernando G

    2015-05-01

    Dermal plates from armored catfish are bony structures that cover their body. In this paper we characterized structural, chemical, and nanomechanical properties of the dermal plates from the Amazonian fish Pterygoplichthys pardalis. Analysis of the morphology of the plates using scanning electron microscopy (SEM) revealed that the dermal plates have a sandwich-like structure composed of an inner porous matrix surrounded by two external dense layers. This is different from the plywood-like laminated structure of elasmoid fish scales but similar to the structure of osteoderms found in the dermal armour of some reptiles and mammals. Chemical analysis performed using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results revealed similarities between the composition of P. pardalis plates and the elasmoid fish scales of Arapaima gigas. Reduced moduli of P. pardalis plates measured using nanoindentation were also consistent with reported values for A. gigas scales, but further revealed that the dermal plate is an anisotropic and heterogeneous material, similar to many other fish scales and osteoderms. It is postulated that the sandwich-like structure of the dermal plates provides a lightweight and tough protective layer.

  15. Sandwich-structured enzyme membrane reactor for efficient conversion of maltose into isomaltooligosaccharides.

    Science.gov (United States)

    Zhang, Lei; Su, Yanlei; Zheng, Yang; Jiang, Zhongyi; Shi, Jiafu; Zhu, Yuanyuan; Jiang, Yanjun

    2010-12-01

    A novel enzyme membrane reactor with sandwich structure has been developed by confining glucosidase between two sheets of ultrafiltration membranes to effectively convert maltose to isomaltooligosaccharides (IMOs). The hydrophilic ultrafiltration membranes, which were prepared by phase inversion method using PES as bulk polymer and Pluronic F127 as both surface modification and pore formation agent, exhibited the desirable enzyme adsorption-resistant property. The scanning electron microscopy (SEM) photographs showed that two sheets of PES/Pluronic F127 membranes were packed tightly and glucosidase was kept in a free state within a nanoscale space. When the weight ratio of Pluronic F127 to PES was 30%, glucosidase could be completely rejected by the membranes. Due to the sandwich structuring of the membrane reactor and the high hydrophilicity of the PES/Pluronic F127 membrane surface, maltose conversion and yield reached 100% and 58% under the optimum experimental conditions (pH 6.0, 50 degrees C), respectively. 2010 Elsevier Ltd. All rights reserved.

  16. Fabrication of mucoadhesive chitosan coated polyvinylpyrrolidone/cyclodextrin/clotrimazole sandwich patches for oral candidiasis.

    Science.gov (United States)

    Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Panomsuk, Suwanee; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

    2015-11-05

    This study aims to fabricate clotrimazole (CZ)-composite sandwich nanofibers using electrospinning. The CZ-loaded polyvinylpyrrolidone (PVP)/hydroxypropyl-β-cyclodextrin (HPβCD) fiber was coated with chitosan-cysteine (CS-SH)/polyvinyl alcohol (PVA) to increase the mucoadhesive properties and to achieve a sustained release of the drug from the nanofibers. The nanofibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffractometry (XRD). The nanofibers mechanical and mucoadhesive properties, drug release, antifungal activity and cytotoxicity were also assessed. The fibers were in the nanoscale with good mucoadhesive properties. The XRPD revealed a molecular dispersion of amorphous CZ in the nanofibers. The initial fast release of CZ from the nanofibers was achieved. Moreover, the sandwich nanofibers coated for longer times resulted in slower release rates compared with the shorter coating times. The CZ-loaded nanofibers killed the Candida significantly faster than the commercial CZ lozenges at 5, 15 and 30 min and were safe for a 2-h incubation. Therefore, these nanofibers may be promising candidates for the treatment of oral candidiasis.

  17. Primary hepatocyte culture in collagen gel mixture and collagen sandwich

    Institute of Scientific and Technical Information of China (English)

    Ying-Jie Wang; Hong-Ling Liu; Hai-Tao Guo; Hong-Wei Wen; Jun Liu

    2004-01-01

    AIM: To explore the methods of hepatocytes culture in a collagen gel mixture or between double layers of collagen sandwich configuration and to examine the functional and cytomorphological characteristics of cultured hepatocytes.METHODS: A two-step collagenase perfusion technique was used to isolate the hepatocytes from Wistar rats or newborn Chinese experimental piglets. The isolated hepatocytes were cultured in a collagen gel mixture or between double layers of collagen sandwich configuration respectively. The former was that rat hepatocytes were mixed with type I rat tail collagen solution till gelled, and the medium was added onto the gel. The latter was that swine hepatocytes were seeded on a plate precoated with collagen gel for 24 h, then another layer of collagen gel was overlaid, resulting in a sandwich configuration. The cytomorphological characteristics, albumin secretion, and LDH-release of the hepatocytes cultured in these two models were examined.RESULTS: Freshly isolated rat hepatocytes were successfully mixed and fixed in collagen gel, and cultured in the gel condition. During the culture period, the urea synthesized and secreted by rat hepatocytes was detected throughout the period. Likewise, newborn experimental piglet hepatocytes were successfully fixed between the double layers of collagen gel, forming a sandwich configuration.Within a week of culture, the albumin secreted by swine hepatocytes was detected by SDS/PAGE analysis. The typical cytomorphological characteristics of the hepatocytes cultured by the above two culture models were found under a phasecontrast microscope. There was little LDH-release during the culture period.CONCLUSION: Both collagen gel mixture and double layers of collagen sandwich configuration can provide cultural conditions much closer to in vivoenvironment, and are helpful for maintaining specific hepatic fiJnctions and cytomorphological characteristics. A collagen gel mixture culture may be more eligible for the

  18. A new ELISA for determination of potency in snake antivenoms.

    Science.gov (United States)

    Rial, A; Morais, V; Rossi, S; Massaldi, H

    2006-09-15

    A competitive ELISA for potency determination of bothropic equine antivenom was developed and compared to the conventional in vivo ED(50) assay, with the aim of partially substituting the in vivo assay in the monitoring of antivenom immunoglobulin levels. On this purpose, blood samples were taken at different times during and after the immunization protocol of the lot of horses used for production of snake antivenom at the Instituto de Higiene, Uruguay. Both the competitive ELISA and the ED(50) assay were performed on those samples. In addition, a group of five commercial pepsin-digested antivenoms were tested by both methods. A significant (P<0.001) correlation (Pearson's r=0.957) was found between the ELISA titres and the corresponding ED(50) values, indicating that the in vitro test can estimate the neutralizing antibody capacity of the sera as well as the in vivo assay. By means of this new ELISA, it was found that the immunized animals maintained good venom antibody titres, in the order of 20-50% of the maximum achieved, even 10 month after the end of the immunization schedule. The main advantage of our ELISA design is its ability to correctly estimate the neutralization capacity of crude hyperimmune plasma and antivenom sera independently of their antibody composition in terms of whole IgG or F(ab')(2) fragment.

  19. The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-24

    This report documents the implementation of several related 1D heat flow problems in the verification package ExactPack [1]. In particular, the planar sandwich class defined in Ref. [2], as well as the classes PlanarSandwichHot, PlanarSandwichHalf, and other generalizations of the planar sandwich problem, are defined and documented here. A rather general treatment of 1D heat flow is presented, whose main results have been implemented in the class Rod1D. All planar sandwich classes are derived from the parent class Rod1D.

  20. Mechanical Response of All-composite Pyramidal Lattice Truss Core Sandwich Structures

    Institute of Scientific and Technical Information of China (English)

    Ming Li; Linzhi Wu; Li Ma; Bing Wang; Zhengxi Guan

    2011-01-01

    The mechanical performance of an all-composite pyramidal lattice truss core sandwich structure was investigated both theoretically and experimentally. Sandwich structures were fabricated with a hot compression molding method using carbon fiber reinforced composite T700/3234. The out-of-plane compression and shear tests were conducted. Experimental results showed that the all-composite pyramidal lattice truss core sandwich structures were more weight efficient than other metallic lattice truss core sandwich structures. Failure modes revealed that node rupture dominated the mechanical behavior of sandwich structures.

  1. Elastic stability of superplastically formed/diffusion-bonded orthogonally corrugated core sandwich plates

    Science.gov (United States)

    Ko, W. L.

    1980-01-01

    The paper concerns the elastic buckling behavior of a newly developed superplastically formed/diffusion-bonded (SPF/DB) orthogonally corrugated core sandwich plate. Uniaxial buckling loads were calculated for this type of sandwich plate with simply supported edges by using orthotropic sandwich plate theory. The buckling behavior of this sandwich plate was then compared with that of an SPF/DB unidirectionally corrugated core sandwich plate under conditions of equal structural density. It was found that the buckling load for the former was considerably higher than that of the latter.

  2. Development of a sandwich enzyme-linked immunosorbent assay for dTMP-GH fusion protein by rational immunogen selection.

    Science.gov (United States)

    Wang, Song; Shen, Mingqiang; Chen, Shilei; Wang, Cheng; Chen, Fang; Chen, Mo; Zhao, Gaomei; Ran, Xinze; Cheng, Tianmin; Su, Yongping; Xu, Yang; Wang, Junping

    2017-12-01

    dTMP-GH is a chimeric protein containing a tandem dimer of thrombopoietin mimetic peptide (dTMP) fused to human growth hormone (hGH) prepared previously by our team. It shows significant bioactivity in promoting thrombocytopoiesis, but detection of intact dTMP-GH in plasma is still a challenge due to the presence of endogenous hGH. In this study, a rabbit polyclonal antibody with high affinity to dTMP was obtained with a BSA-conjugated immunogen composed of 20 amino acids sequence spanning two TMP and the linker. A monoclonal antibody termed as 3B2 was screened out by using immunizing mice with whole dTMP-GH, which was proved to simultaneously interact with rhGH, TMP-GH, and dTMP-GH, respectively. In this study, we developed a specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) with two antibodies (one polyclonal and one HRP-conjugated monoclonal) to quantify dTMP-GH. The polyclonal antibody and HRP-conjugated monoclonal antibody 3B2 were applied as the capture antibody and detection antibody, respectively. A good correlation between ELISA and bicinchoninic acid (BCA) assay in the quantification of diluted dTMP-GH was observed (r(2) = 0.996). Meanwhile, the standard curve of this ELISA method was found in a linear relationship between 0.2 and 10 ng/mL in the presence of rabbit plasma. In vivo experiments demonstrate that the newly developed method is effective to detect dTMP-GH in rabbits, which paves the way for further pharmacokinetic evaluation.

  3. Sandwich-Structured Graphene-Fe3O4@Carbon Nanocomposites for High-Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Zhao, Li; Gao, Miaomiao; Yue, Wenbo; Jiang, Yang; Wang, Yuan; Ren, Yu; Hu, Fengqin

    2015-05-13

    Advanced anode materials for high power and high energy lithium-ion batteries have attracted great interest due to the increasing demand for energy conversion and storage devices. Metal oxides (e.g., Fe3O4) usually possess high theoretical capacities, but poor electrochemical performances owing to their severe volume change and poor electronic conductivity during cycles. In this work, we develop a self-assembly approach for the synthesis of sandwich-structured graphene-Fe3O4@carbon composite, in which Fe3O4 nanoparticles with carbon layers are immobilized between the layers of graphene nanosheets. Compared to Fe3O4@carbon and bulk Fe3O4, graphene-Fe3O4@carbon composite shows superior electrochemical performance, including higher reversible capacity, better cycle and rate performances, which may be attributed to the sandwich structure of the composite, the nanosized Fe3O4, and the carbon layers on the surface of Fe3O4. Moreover, compared to the reported graphene-Fe3O4 composite, the particle size of Fe3O4 is controllable and the content of Fe3O4 in this composite can be arbitrarily adjusted for optimal performance. This novel synthesis strategy may be employed in other sandwich-structured nanocomposites design for high-performance lithium-ion batteries and other electrochemical devices.

  4. Semi-in situ atomic force microscopy imaging of intracellular neurofilaments under physiological conditions through the 'sandwich' method.

    Science.gov (United States)

    Sato, Fumiya; Asakawa, Hitoshi; Fukuma, Takeshi; Terada, Sumio

    2016-08-01

    Neurofilaments are intermediate filament proteins specific for neurons and characterized by formation of biochemically stable, obligate heteropolymers in vivo While purified or reassembled neurofilaments have been subjected to morphological analyses by electron microscopy and atomic force microscopy, there has been a need for direct imaging of cytoplasmic genuine intermediate filaments with minimal risk of artefactualization. In this study, we applied the modified 'cells on glass sandwich' method to exteriorize intracellular neurofilaments, reducing the risk of causing artefacts through sample preparation. SW13vim(-) cells were double transduced with neurofilament medium polypeptide (NF-M) and alpha-internexin (α-inx). Cultured cells were covered with a cationized coverslip after prestabilization with tannic acid to form a sandwich and then split into two. After confirming that neurofilaments could be deposited on ventral plasma membranes exposed via unroofing, we performed atomic force microscopy imaging semi-in situ in aqueous solution. The observed thin filaments, considered to retain native structures of the neurofilaments, exhibited an approximate periodicity of 50-60 nm along their length. Their structural property appeared to reflect the morphology formed by their constituents, i.e. NF-M and α-inx. The success of semi-in situ atomic force microscopy of exposed bona fide assembled neurofilaments through separating the sandwich suggests that it can be an effective and alternative method for investigating cytoplasmic intermediate filaments under physiological conditions by atomic force microscopy.

  5. Interface fatigue crack propagation in sandwich X-joints – Part I: Experiments

    DEFF Research Database (Denmark)

    Moslemian, Ramin; Berggreen, Christian

    2013-01-01

    In this study, face/core fatigue crack growth in sandwich X-joints is investigated numerically and experimentally. The work presented here covers Part I of the study which includes an experimental investigation of fatigue crack growth in sandwich X-joints and characterization of the face/core int......In this study, face/core fatigue crack growth in sandwich X-joints is investigated numerically and experimentally. The work presented here covers Part I of the study which includes an experimental investigation of fatigue crack growth in sandwich X-joints and characterization of the face....../core interface of the joints. Sandwich tear test specimens with a face/core debond representing a debonded sandwich X-joint were tested under cyclic loading. Fatigue tests were conducted on the sandwich tear test specimens with H45, H100 and H250 PVC cores and glass/polyester face sheets. The Digital Image...

  6. Compressive and shear buckling analysis of metal matrix composite sandwich panels under different thermal environments

    Science.gov (United States)

    Ko, William L.; Jackson, Raymond H.

    1993-01-01

    Combined inplane compressive and shear buckling analysis was conducted on flat rectangular sandwich panels using the Raleigh-Ritz minimum energy method with a consideration of transverse shear effect of the sandwich core. The sandwich panels were fabricated with titanium honeycomb core and laminated metal matrix composite face sheets. The results show that slightly slender (along unidirectional compressive loading axis) rectangular sandwich panels have the most desirable stiffness-to-weight ratios for aerospace structural applications; the degradation of buckling strength of sandwich panels with rising temperature is faster in shear than in compression; and the fiber orientation of the face sheets for optimum combined-load buckling strength of sandwich panels is a strong function of both loading condition and panel aspect ratio. Under the same specific weight and panel aspect ratio, a sandwich panel with metal matrix composite face sheets has much higher buckling strength than one having monolithic face sheets.

  7. Outbreak of Salmonella indiana associated with egg mayonnaise sandwiches at an acute NHS hospital.

    Science.gov (United States)

    Mason, B W; Williams, N; Salmon, R L; Lewis, A; Price, J; Johnston, K M; Trott, R M

    2001-12-01

    An outbreak of Salmonella indiana infection in December 2000 affected 17 staff, relatives and patients at an acute NHS Hospital in Swansea. Epidemiological investigation identified egg mayonnaise sandwiches as the vehicle of infection. It was not possible to definitively determine the source of the infection or how the prepared sandwiches became contaminated. The most likely explanation was a pasteurisation failure of a batch of the egg roll used to make these sandwiches. Sandwiches are the most frequently identified vehicle of infection in foodborne outbreaks of salmonella infection in hospitals in England and Wales. The process of sandwich preparation has inherent risks because it involves considerable handling of food, which is consumed without further cooking. Care is required in all stages of preparation including the sourcing of materials used to produce the sandwiches. NHS Trusts should review their Hazard Analysis Critical Control Point plans for sandwich production.

  8. Extending the ELisA Logbook to use MySQL

    CERN Document Server

    Osman Jama Ali, Yosuf

    2017-01-01

    ELisA (Electronic Logbook for the Information Storage of ATLAS Experiments at LHC) is a web tool that is used within the ATLAS community to keep track of the daily experiments and deployments within ATLAS. It is implemented using the Spring framework and consists of a web interface, a REST API and a set of client libraries. This Report summarises the process taken in replacing the Oracle database that is used with MySQL, as well as the incorporation of Docker as a deployment strategy in order to make the logbook more portable.

  9. Development and Preliminary Application of ELISA Method for Diphtheria Toxoid%白喉类毒素ELISA检测方法的建立及初步应用

    Institute of Scientific and Technical Information of China (English)

    刘朝阳; 景辉; 陈艳红; 张斌; 马相虎; 朱金华

    2011-01-01

    目的 建立白喉类毒素双抗体夹心ELISA检测方法,并进行验证及初步应用.方法 以马抗白喉类毒素血清作为包被抗体,HRP标记的白喉絮状反应抗毒素作为酶标抗体,建立白喉类毒素双抗体夹心ELISA检测方法,并对该方法进行重复性、特异性验证、最佳线性范围和检测限确定及初步应用.结果 经验证,该方法重复性好,特异性强,白喉类毒素含量在0.9765~125.0000ng/ml之间时线性关系良好,检测限为7.812 ng/ml,该方法检测了3批白喉类毒素原液,与动物实验结果基本相符.结论 已建立了白喉类毒素双抗体夹心ELISA检测方法,可用于检测白喉类毒素的含量和抗原性.%Objective To develop, verify and preliminarily apply a double antibody sandwich ELISA method for diphtheria toxoid. Methods A double antibody sandwich ELISA method was developed using horse antiserum against diphtheria toxoid as coating antibody and HRP-labeled diphtheria flocculation antitoxin as enzyme labeled antibody, then verified for reproducibility and specificity, determined for optimal linear range and detection limit, and applied preliminarily. Results The developed method showed high reproducibility and specificity, of which the optimal linear range and detection limit were 0. 976 5 ~ 125. 000 0 ng/ml and 7. 812 ng/ml respectively. Three batches of bulk diphtheria toxoid were detected by the developed method, and the results were basically consistent with thoes by animal test. Conclusion A double antibody sandwich ELISA method was developed, which might be used for determination of content and antigenicity of diphtheria toxoid.

  10. ELISA reader does not interfere by mobile phone radiofrequency radiation.

    Science.gov (United States)

    Mortazavi, Seyyed Mohammad Javad; Baradaran-Ghahfarokhi, Hamid Reza; Abdi, Mohammad Reza; Baradaran-Ghahfarokhi, Milad; Mostafavi, Nayyer Sadat; Mahmoudi, Golshan; Berenjkoub, Nafiseh; Akmali, Zahra; Hossein-Beigi, Fahimeh; Arsang, Vajiheh

    2016-01-01

    The increasing number of mobile phones can physically cause electromagnetic interference (EMI) in medical environments; can also cause errors in immunoassays in laboratories. The ELISA readers are widely used as a useful diagnostic tool for Enzymun colorimetric assay in medicine. The aim of this study was to investigate whether the ELISA reader could be interfered by the exposure to the 900 MHz cell phones in the laboratory. Human serum samples were collected from 14 healthy donors (9 women and 5 men) and each sample was divided into four aliquots and was placed into four batches for the in-vitro quantitative determination of human chorionic gonadotropin (hCG). During colorimetric reading of the first, second, and third batches, the ELISA reader (Stat Fax 2100, Awareness Technology, Inc., USA) was exposed to 0.5, 1.0, and 2.0 W exposure of 900 MHz radiation, respectively. For the forth batch (control group), no radiation was applied. All experiments were performed comparing ELISA read out results of the I, II, and III batches with the control batch, using the Wilcoxon test with criterion level of P = 0.050. The final scores in the exposed batches I, II, and III were not statistically significant relative to the control batch (P > 0.05). The results showed that 900 MHz radiation exposure did not alter the ELISA measured levels of hCG hormone in I (P = 0.219), II (P = 0.909), and III (P = 0.056) batches compared to the control batch. This study showed that ELISA reader does not interfere by mobile phone RF radiation at a closed contact (less than 5 cm distance). However, we recommend that medical institutions discuss these issues in the context of their specific use of technologies and frame a policy that is clear and straightforward to guide staff, patients, and visitors.

  11. [The systematization of the enzyme-linked immunosorbent assay (=ELISA)].

    Science.gov (United States)

    Gränzer, W

    1989-06-01

    Using the example of the detectability of immunological methods the study shows the considerable influence exerted by this detectability on the quantitative and qualitative parameters and the necessity of a systematization of the methods. This systematization already starts with the product labeling: A sufficient description of antibodies has to contain five qualities. The profitability of the experimental research is improved by optimized product and method systematization. ELISA is presented in a systematized form as a modular system optimizing the comparability of these methods. In order to detect the gain of information transparency obtained by systematization, an ELISA, described in the literature, is presented in the original and in the systematized form.

  12. Validación de un ELISA para la cuantificación de las impurezas proteicas de la cepa hospedera en el principio activo de la vacuna recombinante cubana contra la hepatitis B

    OpenAIRE

    Eliana Pérez; Susset Valderrama; Alain Baxera; Yunaisy Jiménez; Gerardo García; Lourdes Costa; Marisel Quintana

    2014-01-01

    Se validó un inmunoensayo tipo sandwich de doble anticuerpo para cuantificar las impurezas proteicas de la cepa hospedera que pueden estar presentes en el principio activo de la vacuna cubana contra la hepatitis B. Se prepararon los reactivos biológicos empleados en el ELISA. Las proteínas de la cepa hospedera se obtuvieron bajo las mismas condiciones que el proceso de producción de la proteína recombinante hasta un paso de semipurificación o purificación primaria. Los antisueros dirigidos co...

  13. Clinical evaluation of the Serum CrossLaps One Step ELISA, a new assay measuring the serum concentration of bone-derived degradation products of type I collagen C-telopeptides

    DEFF Research Database (Denmark)

    Christgau, S; Rosenquist, C; Alexandersen, P

    1998-01-01

    The Serum CrossLaps One Step ELISA is a sandwich assay using two monoclonal antibodies specific for a beta-aspartate form of the epitope EKAHDGGR derived from the carboxy-terminal telopeptide region of type I collagen alpha1-chain. Our objective was to assess the clinical value of the Serum Cross......Laps assay for monitoring antiresorptive therapy in osteoporosis treatment. Samples obtained from postmenopausal women treated with different doses of cyclic or continuous hormone replacement therapy (HRT) with an estrogen analog (tibolone) or with a bisphosphonate (ibandronate) were measured in the Serum...

  14. Fate of Estrogens in Soils and Detection by ELISA

    Science.gov (United States)

    Caron, Emmanuelle; Sheedy, Claudia; Farenhorst, Annemieke; Zvomuya, Francis; Gaultier, Jeanette; Goddard, Tom

    2010-05-01

    Land application of manure can contribute to the release of estrogenic compounds in the environment. Estrogens may move from soils to water by processes such as runoff and leaching. The objectives of the present study were to determine the fate of estrogens in soils and to develop a detection method for these compounds. The sorption (soil sorption coefficient (Kd) and sorption coefficient per unit organic carbon (Koc)) of 17β-estradiol, estrone, estriol and equol were studied, using batch equilibrium experiments, in 121 surface soils from Alberta, Canada. The mineralization of [4-14C] 17β-estradiol was determined in soil microcosms in a subset of 36 samples. Quantitative relationships at the regional level were explored using partial least squares regression (PLS) (between Kd or Koc values and soil properties) and by ordinary least squares regression (between Kd or Koc values of different estrogens). Soil properties (r2 0.51-0.87 for Kd and 0.32-0.44 for Koc) provided better prediction models than using the data of different estrogens (r2 0.38-0.71 for Kd and 0.18-0.40 for Koc). PLS regression models for mineralization parameters of 17ß-estradiol had lower predictive power (lower r2)than models developed for sorption parameters. In addition, it has become of primary importance to develop sensitive detection methods that are able to detect low estrogen concentrations (ng L-1) in a wide variety of environmental matrices in order to validate the prediction of their fate and to study their presence in affected ecosystems. Conjugates were synthesized using a mixed anhydride reaction and two Enzyme-Linked Immunosorbent Assays (ELISAs) were developed using polyclonal antibodies. One ELISA was highly specific for 17β-estradiol (with an IC50 of 243 ng mL-1) and the second allowed for the broader detection of 17β-estradiol, estrone and estriol (with an IC50 of 18 ng mL-1 for 17β-estradiol). The cross-reactivity of both ELISAs was studied against 13 compounds (natural

  15. Detection of botulinum neurotoxin serotype B at sub mouse LD(50 levels by a sandwich immunoassay and its application to toxin detection in milk.

    Directory of Open Access Journals (Sweden)

    Miles C Scotcher

    Full Text Available BACKGROUND: Botulinum neurotoxin (BoNT, the causative agent of botulism, a serious neuroparylatic disease, is produced by the anaerobic bacterium Clostridium botulinum and consists of a family of seven serotypes (A-H. We previously reported production of high-affinity monoclonal antibodies to BoNT serotype A. METHODS AND FINDINGS: Recombinant peptide fragments of the light chain, the transmembrane and receptor-binding domains of the heavy chain of botulinum neurotoxin type B (BoNT/B were expressed in Escherichia coli as GST-fusion proteins and purified. These proteins were used to immunize BALB/cJ mice for the generation of monoclonal antibodies (mAbs. Antibody-producing hybridomas were detected using either a direct binding ELISA binding to plate-immobilized BoNT/B, or with a capture-capture ELISA whereby the capacity of the antibody to capture BoNT/B from solution was tested. A total of five mAbs were selected, two of which bound the toxin light chain and three bound the receptor-binding domain of BoNT/B heavy chain. MAb MCS6-27 was identified via capture-capture ELISA and was the only mAb able to bind BoNT/B in solution under physiological conditions. MAbs F24-1, F26-16, F27-33 and F29-40 were identified via direct binding ELISA, and were able to capture BoNT/B in solution only in the presence of 0.5-0.9 mM sodium dodecyl sulphate (SDS. MAb MCS6-27 and an anti-BoNT/B polyclonal antibody were incorporated into a sandwich ELISA that did not require SDS. CONCLUSIONS: We report here the generation of monoclonal antibodies to serotype B and the subsequent development of a sensitive sandwich immunoassay. This immunoassay has a detection limit of 100 fg BoNT/B, fifty times more sensitive than the mouse bioassay detection limit of 5 pg BoNT/B. Additionally, this assay detected as little as 39 pg/mL of toxin in skim, 2% and whole milk.

  16. Sandwich module testing for space solar power

    Science.gov (United States)

    Jaffe, Paul

    Solar power satellites have been envisioned as a means to provide electricity for terrestrial use. The approach entails collection of solar energy in space and its wireless transmission to the earth. This potentially gives the benefit of provision of baseload power while avoiding the losses due to the day/night cycle and tropospheric effects that are associated with terrestrial solar power. Proponents have contended that the implementation of such systems could offer energy security, environmental, and technological advantages to those who would undertake their development. Among recent implementations commonly proposed for SSP, the Modular Symmetrical Concentrator and other modular concepts have received considerable attention. Each employs an array of modules for performing conversion of concentrated sunlight into microwaves or laser beams for transmission to earth. The research described herein details efforts in the development and testing of photovoltaic arrays, power electronics, microwave conversion electronics, and antennas for 2.45 GHz microwave-based “ sandwich” module prototypes. Prototypes were designed, fabricated, and subjected to the challenging conditions inherent in the space environment, including the solar concentration levels in which an array of modules might be required to operate.

  17. Study of Immunoassay Methods for Recombinant Human Erythropoietin(rhEPO)Using Competitive ELISA

    Institute of Scientific and Technical Information of China (English)

    Jin YAN; Jie Bo MI; Wen Bao CHANG

    2004-01-01

    Two different immunoassay methods, competitive indirect enzyme-linked immuno- sorbent assay (CI-ELISA) and amplificative competitive indirect ELISA (ACI-ELISA) using biotin-avidin complex system were studied to detect rhEPO.The linear ranges were 50-20000 ng/mL and 10-50000 ng/mL for CI-ELISA and ACI-ELISA, respectively.The low detection limits of CI-ELISA and ACI-ELISA were 62.8 ng/mL and 8.5 ng/mL, respectively.

  18. Model for impedance of an ionic conductor sandwiched between blocking electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.C.

    1992-06-24

    The simplest model for the impedance of an ionic conductor sandwiched between two blocking electrodes is a resistor in series with a capacitor (rc pair) representing the bulk material and the conductor-electrode interface, respectively, and a second capacitor parallel to the rc pair representing the electronic dielectric response of the system. In practice, to describe the experimental data satisfactorily, one needs to replace the interface capacitor with a constant-phase-angle (CPA) element and to add a non-Debye dielectric element parallel to the resistor to represent the local ionic movement. In this paper, some of the existing physical models for the CPA and non-Debye dielectric elements are discussed, and an example is presented for analyzing the impedance data using the resultant circuit model.

  19. Improved Thermoelectric Performance in Flexible Tellurium Nanowires/Reduced Graphene Oxide Sandwich Structure Hybrid Films

    Science.gov (United States)

    Gao, Jie; Liu, Chengyan; Miao, Lei; Wang, Xiaoyang; Peng, Ying; Chen, Yu

    2016-11-01

    With a high flexibility and an adjustable electronic structure, reduced graphene oxide (RGO) is a potential candidate for flexible thermoelectric materials. Here, we report that flexible RGO/tellurium nanowires (Te NWs)/RGO sandwich structure hybrid films are prepared on glass fabrics through the drop-cast method. The addition of 20 wt.% Te NWs into a RGO matrix remarkably improves the Seebeck coefficient from 15.2 μV/K to 89.7 μV/K while maintaining relatively high electrical conductivity, thus resulting in a one order of magnitude higher power factor value compared with the Te NWs. According to the values of carrier mobility and concentration of hybrid films, the improved thermoelectric properties are presented because of the energy filtering effect on the interfaces in hybrid films. This article suggests that RGO/Te NWs/RGO hybrid films would be promising for fabricating flexible energy sources.

  20. Model for impedance of an ionic conductor sandwiched between blocking electrodes. [Example: yttria-stabilized zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.C.

    1992-06-24

    The simplest model for the impedance of an ionic conductor sandwiched between two blocking electrodes is a resistor in series with a capacitor (rc pair) representing the bulk material and the conductor-electrode interface, respectively, and a second capacitor parallel to the rc pair representing the electronic dielectric response of the system. In practice, to describe the experimental data satisfactorily, one needs to replace the interface capacitor with a constant-phase-angle (CPA) element and to add a non-Debye dielectric element parallel to the resistor to represent the local ionic movement. In this paper, some of the existing physical models for the CPA and non-Debye dielectric elements are discussed, and an example is presented for analyzing the impedance data using the resultant circuit model.

  1. Sandwich-like, graphene-based titania nanosheets with high surface area for fast lithium storage

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shubin; Feng, Xinliang; Muellen, Klaus [Max Planck Institute for Polymer Research, Mainz (Germany)

    2011-08-16

    Sandwich-like, graphene-based mesoporous titania (G-TiO{sub 2}) nanosheets possess thin thickness, large aspect ratio, and mesoporous structure and show enhanced electrical conductivity. Such unique features provide numerous open channels for the access of electrolyte and facilitate the fast diffusion of lithium ions during the cycling processes. The graphene layer within each nanosheet can act as a mini-current collector, which is favorable for the fast electron transport in the electrode. As a consequence, G-TiO{sub 2} nanosheets exhibit a ultrahigh rate capability and excellent cycle performance, holding great potential as a high-rate anode material for lithium storage. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Improved Thermoelectric Performance in Flexible Tellurium Nanowires/Reduced Graphene Oxide Sandwich Structure Hybrid Films

    Science.gov (United States)

    Gao, Jie; Liu, Chengyan; Miao, Lei; Wang, Xiaoyang; Peng, Ying; Chen, Yu

    2017-05-01

    With a high flexibility and an adjustable electronic structure, reduced graphene oxide (RGO) is a potential candidate for flexible thermoelectric materials. Here, we report that flexible RGO/tellurium nanowires (Te NWs)/RGO sandwich structure hybrid films are prepared on glass fabrics through the drop-cast method. The addition of 20 wt.% Te NWs into a RGO matrix remarkably improves the Seebeck coefficient from 15.2 μV/K to 89.7 μV/K while maintaining relatively high electrical conductivity, thus resulting in a one order of magnitude higher power factor value compared with the Te NWs. According to the values of carrier mobility and concentration of hybrid films, the improved thermoelectric properties are presented because of the energy filtering effect on the interfaces in hybrid films. This article suggests that RGO/Te NWs/RGO hybrid films would be promising for fabricating flexible energy sources.

  3. Interfacial assembly of sandwich mixed (Phthalocyaninato)(Porphyrinato) rare earth triple-decker complexes

    Energy Technology Data Exchange (ETDEWEB)

    Liu Qingyun [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Department of Chemistry, Shandong University, Jinan 250100 (China); Li Yong; Liu Hongguo [Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Department of Chemistry, Shandong University, Jinan 250100 (China); Jiang Jianzhuang [Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Department of Chemistry, Shandong University, Jinan 250100 (China); Department of Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Bian Yongzhong, E-mail: yzbian@sas.ustb.edu.cn [Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Department of Chemistry, Shandong University, Jinan 250100 (China); Department of Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2011-07-20

    Interfacial assembly of sandwich mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes [(Pc)Eu(Pc)Eu(TPyP)] (1) and [(TPyP)Sm(Pc)Sm(TPyP)] (2) (Pc = phthalocyaninate, TPyP = meso-tetrakis(4-pyridyl)porphyrinate) has been comparatively studied at the air/pure water and the air/CdCl{sub 2} aqueous solution subphase interfaces. Surface pressure-area isotherms revealed the remarkable increase of limiting mean molecular area of the triple-deckers with the presence of Cd{sup 2+}, suggesting the occurrence of in situ interfacial coordination. The formation of coordination bonds between the pyridyl groups of TPyP macrocycles in the triple-deckers and Cd{sup 2+} ions from the subphase was further supported by FT-IR spectroscopic data. Electronic absorption measurements showed the formation of J-aggregates of the triple-decker molecules in the interfacial assembled films.

  4. ELISA reader does not interfere by mobile phone radiofrequency radiation

    Directory of Open Access Journals (Sweden)

    Seyyed Mohammad Javad Mortazavi

    2016-01-01

    Conclusion: This study showed that ELISA reader does not interfere by mobile phone RF radiation at a closed contact (less than 5 cm distance. However, we recommend that medical institutions discuss these issues in the context of their specific use of technologies and frame a policy that is clear and straightforward to guide staff, patients, and visitors.

  5. Evaluating the performance of gluten ELISA test kits

    NARCIS (Netherlands)

    Bruins Slot, I.D.; Bremer, Maria G.E.G.; Fels-Klerx, Van Der Ine; Hamer, R.J.

    2015-01-01

    A wide variety of enzyme-linked immunosorbent assays (ELISAs) are commercially available for gluten detection in food, including new formats and assays with antibodies against relevant gluten epitopes. Nevertheless, problems persist to accurately determine the gluten content of products. In this

  6. Impact load mitigation in sandwich beams using local resonators

    CERN Document Server

    Sharma, B

    2015-01-01

    Dynamic response of sandwich beams with resonators embedded in the cores subjected to impact loads is studied. Using finite element models the effectiveness of various local resonator frequencies under a given impact load is compared to the behavior of an equivalent mass beam. It is shown that addition of appropriately chosen local resonators into the sandwich beam is an effective method of improving its flexural bending behavior under impact loads. The effect of a given local resonance frequency under different impact load durations is also studied. It is demonstrated that the choice of appropriate local resonance frequency depends on the impact duration. Further, by performing transverse impact experiments, the finite element models are verified and the advantage of using internal resonators under impact loading conditions is demonstrated.

  7. Preserving entanglement under decoherence and sandwiching all separable states

    CERN Document Server

    Lockhart, R B; Lockhart, Robert; Steiner, Michael

    2000-01-01

    Every entangled state can be perturbed, for instance by decoherence, and stay entangled. For a large class of pure entangled states, we show how large the perturbation can be. Our class includes all pure bipartite and all maximally entangled states. For an entangled state, E, the constucted neighborhood of entangled states is the region outside two parallel hyperplanes, which sandwich the set of all separable states. The states for which these neighborhoods are largest are the maximally entangled ones. As the number of particles, or the dimensions of the Hilbert spaces for two of the particles increases, the distance between two of the hyperplanes which sandwich the separable states goes to zero. It is easy to decide if a state Q is in the neighborhood of entangled states we construct for an entangled state E. One merely has to check if the trace of EQ is greater than a constant which depends upon E and which we determine.

  8. Non-linear Behavior of Curved Sandwich Panels

    DEFF Research Database (Denmark)

    Berggreen, Carl Christian; Jolma, P.; Karjalainen, J. P.;

    2003-01-01

    In this paper the non-linear behavior of curved sandwich panels is investigated both numerically and experimentally. Focus is on various aspects of finite element modeling and calculation procedures. A simply supported, singly curved, CFRP/PVC sandwich panel is analyzed under uniform pressure load...... and results are compared to test data. A novel test arrangement utilizing a water filled cushion to create the uniform pressure load on curved panel specimen is used to obtain the experimental data. The panel is modeled with three different commercial finite element codes. Two implicit and one explicit code...... are used with various element types, modeling approaches and material models. The results show that the theoretical and experimental methods generally show fair agreement in panel non-linear behavior before collapse. It is also shown that special attention to detail has to be taken, because the predicted...

  9. Non-Uniform Compressive Strength of Debonded Sandwich Panels

    DEFF Research Database (Denmark)

    Berggreen, Carl Christian; Simonsen, Bo Cerup

    2005-01-01

    This article describes the development, validation and application of a FEM based numerical model for prediction of residual strength of damaged sandwich panels. The core of the theoretical method is a newly developed procedure for prediction of the propagation of a face-core debond. As demonstra......This article describes the development, validation and application of a FEM based numerical model for prediction of residual strength of damaged sandwich panels. The core of the theoretical method is a newly developed procedure for prediction of the propagation of a face-core debond.......(2005)., shows that the model is indeed able to predict the failure modes and the residual strength of damaged panels with accuracy sufficient for practical applications. This opens up for a number of important engineering applications, for example risk-based inspection and repair schemes....

  10. Applications of thin-film sandwich crystallization platforms

    Energy Technology Data Exchange (ETDEWEB)

    Axford, Danny, E-mail: danny.axford@diamond.ac.uk; Aller, Pierre; Sanchez-Weatherby, Juan; Sandy, James [Diamond Light Source, Harwell Oxford, Didcot OX11 0DE (United Kingdom)

    2016-03-24

    Crystallization via sandwiches of thin polymer films is presented and discussed. Examples are shown of protein crystallization in, and data collection from, solutions sandwiched between thin polymer films using vapour-diffusion and batch methods. The crystallization platform is optimal for both visualization and in situ data collection, with the need for traditional harvesting being eliminated. In wells constructed from the thinnest plastic and with a minimum of aqueous liquid, flash-cooling to 100 K is possible without significant ice formation and without any degradation in crystal quality. The approach is simple; it utilizes low-cost consumables but yields high-quality data with minimal sample intervention and, with the very low levels of background X-ray scatter that are observed, is optimal for microcrystals.

  11. Sandwich-like Reconstruction of Anterior Skull Base Defects

    Institute of Scientific and Technical Information of China (English)

    Wang Zheng-min; Wang De-hui

    2001-01-01

    Objective: To evaluate the safety and efficacy of new modality of anterior skull base repair,namely sandwich-like reconstruction of anterior skull base defects. Methods: A retrospective analysis of patients who underwent transcranial or transcranial-facial resections of malignant or benign aggressive tumors involving the anterior skull base was conducted in our department. We used the sandwich-like reconstruction, using pedicled pericranial flap, frontal muscle flap and free abdominal adipose tissue between them, to separate of cranial cavity and aerodigest tract and keep the frontal lobes in place following resections of anterior skull base tumors. Results: From October, 1984 to October, 1998, 116 patients underwent transcranial or transcranialfacial approach for the resection of malignant or aggressive benign tumor, and sandwich-like repairs were performed for the anterior skull base defect. 54 (46.6 % ) patients had previous operation, with a maximum of 5 surgeries. The average age of patients was 35.9 years old, ranging form 6 to 73 years old. Forty-eight (41.4%)patients had malignant neoplasmas, and sixty-eight (58.6%) patients had benign aggressive tumors. In our series, with the maximal follow-ups for as long as 14 years, NO one had early failure of the one-stage reconstruction. CSF fluid leakage was not encountered, nor was ascending bacterial meningitis observed. No immediate or delayed prolapse of dura or frontal lobes was observed. Conclusion: We conclude that the sandwich-like reconstruction, using pericranial flap, frontal muscle flap and free abdominal adipose between them, is an extremely safe and effective procedure for the repair of skull base defect, even when tumor extensively involves anterior skull base.

  12. Sandwich-like Reconstruction of Anterior Skull Base Defects

    Institute of Scientific and Technical Information of China (English)

    WangZheng-min,MD; WangDe-hui,MD

    2001-01-01

    Objective:To evaluate the safety and efficacy of new modality of anterior skull base repair,namely sandwich-like reconstruction of anterior skull base defects. Methods : A retrospective analysis of patients who underwent wanscranial or wanscranial-facial resections of malignant or benign aggressive tumors involving the anterior skull base was conducted in our department. We used the sandwich-like reconstruction, using pedicled pericranial flap, frontal muscle flap and free abdominal adipose tissue between them, to separate of cranial cavity and aerodigest tract and keep the frontal lobes in place following resections of anterior skull base tumors. Results: From October, 1984 to October, 1998, 116 patients underwent tmnscranial or tmnscranial-facial approach for the resection of malignant or aggressive benign tumor, and sandwich-like repairs were performed for the anterior skull base defect.54 (46.6%) patients had previous operation, with a maximum of 5 surgeries. The average age of patients was 35.9 years old, ranging form 6 to 73 years old. Forty-eight (41.4%) patients had malignant neoplasmas, and sixty-eight (58.6%) patients had benign aggressive tumors. In our series, with the maximal follow-ups for as long as 14 years, NO one had early failure of the one-stage reconstruction. CSF fluid leakage was not encountered, nor was ascending bacterial meningitis observed. No immediate or delayed prolapse of dura or frontal lobes was observed. Conclusion: We conclude that the sandwich-like reconstruction, using pericranial flap, frontal muscle flap and free abdominal adipose between them, is an extremely safe and effective procedure for the repair of skull base defect, even when tumor extensively involves anterior skull base.

  13. Residual Strength of In-plane Loaded Debonded Sandwich Panels

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Nøkkentved, Alexandros; Berggreen, Carl Christian

    2005-01-01

    Face/core debond damaged sandwich panels exposed to uniform and non-uniform compression loads are studied experimentally. The panel geometry is full-scale rectangular with a centrally located circular prefabricated debond. The results show a considerable strength reduction with increasing debond...... diameter, with the failure mechanisms varying between buckling driven debond propagation and face compression failure for large and small debonds respectively....

  14. Sandwiched R\\'enyi Convergence for Quantum Evolutions

    OpenAIRE

    Müller-Hermes, Alexander; Franca, Daniel Stilck

    2016-01-01

    We study the speed of convergence of a primitive quantum time evolution towards its fixed point in the distance of sandwiched R\\'enyi divergences. For each of these distance measures the convergence is typically exponentially fast and the best exponent is given by a constant (similar to a logarithmic Sobolev constant) depending only on the generator of the time evolution. We establish relations between these constants and the logarithmic Sobolev constants as well as the spectral gap. An impor...

  15. The Generalized Thin-Sandwich Problem and its Local Solvability

    CERN Document Server

    Giulini, D

    1999-01-01

    We consider Einstein Gravity coupled to dynamical matter consisting of a gauge field with any compact gauge group and minimally coupled scalar fields. We investigate the conditions under which a free specification of a spatial field configuration for the total system and its derivative with respect to coordinate-time determines a solution to the field equations (generalized thin-sandwich problem). Sufficient conditions for local solvability (in the space of fields) are established.

  16. An asymptotically exact theory of smart sandwich shells

    CERN Document Server

    Le, Khanh Chau

    2016-01-01

    An asymptotically exact two-dimensional theory of elastic-piezoceramic sandwich shells is derived by the variational-asymptotic method. The error estimation of the constructed theory is given in the energetic norm. As an application, analytical solution to the problem of forced vibration of a circular elastic plate partially covered by two piezoceramic patches with thickness polarization excited by a harmonic voltage is found.

  17. Flexural Behavior of Two-Way Sandwiched Slabs

    OpenAIRE

    Pachpande, Jivan Vilas

    2015-01-01

    This dissertation presents the details of the findings of a study focused on evaluating the structural behavior of three-dimensional (3D) cementitious sandwich panels with Expanded Polystyrene (EPS) foam core for two-way slab applications. In this study, both theoretical and finite element numerical analysis procedures were adopted to predict the performance of such slabs under out-of-plane loading conditions. The results from theoretical and finite element analysis were verified by compariso...

  18. Graphene Sandwiched Mesostructured Li-Ion Battery Electrodes.

    Science.gov (United States)

    Liu, Jinyun; Zheng, Qiye; Goodman, Matthew D; Zhu, Haoyue; Kim, Jinwoo; Krueger, Neil A; Ning, Hailong; Huang, Xingjiu; Liu, Jinhuai; Terrones, Mauricio; Braun, Paul V

    2016-09-01

    A deterministic graphene-sandwiched Li-ion battery electrode consisting of an integrated 3D mesostructure of electrochemically active materials and graphene is presented. As demonstrations, electrodes with active nanomaterials that coat (V2 O5 @graphene@V2 O5 cathode) or are coated by (graphene@Si@graphene anode) graphene are fabricated. These electrodes exhibit high capacities and ultralong cycle lives (the cathode can be cycled over 2000 times with minimal capacity fade).

  19. Double Rosensweig instability in a ferrofluid sandwich structure

    OpenAIRE

    Rannacher, Dirk; Engel, Andreas

    2003-01-01

    We consider a horizontal ferrofluid layer sandwiched between two layers of immiscible non-magnetic fluids. In a sufficiently strong vertical magnetic field the flat interfaces between magnetic and non-magnetic fluids become unstable to the formation of peaks. We theoretically investigate the interplay between these two instabilities for different combinations of the parameters of the fluids and analyze the evolving interfacial patterns. We also estimate the critical magnetic field strength at...

  20. Two-dimensional analysis of shallow sandwich panels

    DEFF Research Database (Denmark)

    Skvortsov, V; Bozhevolnaya, Elena

    2001-01-01

    The shallow singly curved and rectangular in-plane sandwich panels affected by lateral loads are considered. The set of governing equations on the basis of the Timoshenko-Reissner plate theory is derived for these panels in the case of general boundary conditions. Usage of any real boundary condi...... all four edges and for the panel that is simply supported along its curved boundaries and has hinge-like supports along the straight boundaries. (C) 2001 Elsevier Science Ltd. All rights reserved....

  1. Residual Strength of In-plane Loaded Debonded Sandwich Panels

    DEFF Research Database (Denmark)

    Berggreen, Carl Christian; Simonsen, Bo Cerup

    2005-01-01

    This paper presents a FEM based numerical model for prediction of residual strength of damaged sandwich panels. As demonstrated, the model can predict the maximum load carrying capacity of real-life panels with debond damages, where the failure is governed by face-sheet buckling followed by debond...... growth. Comparison of the theoretical predictions is carried out against a series of largescale experiments described in Lundsgaard-Larsen et al. (2005)...

  2. Sandwich Structured Composites for Aeronautics: Methods of Manufacturing Affecting Some Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Aneta Krzyżak

    2016-01-01

    Full Text Available Sandwich panels are composites which consist of two thin laminate outer skins and lightweight (e.g., honeycomb thick core structure. Owing to the core structure, such composites are distinguished by stiffness. Despite the thickness of the core, sandwich composites are light and have a relatively high flexural strength. These composites have a spatial structure, which affects good thermal insulator properties. Sandwich panels are used in aeronautics, road vehicles, ships, and civil engineering. The mechanical properties of these composites are directly dependent on the properties of sandwich components and method of manufacturing. The paper presents some aspects of technology and its influence on mechanical properties of sandwich structure polymer composites. The sandwiches described in the paper were made by three different methods: hand lay-up, press method, and autoclave use. The samples of sandwiches were tested for failure caused by impact load. Sandwiches prepared in the same way were used for structural analysis of adhesive layer between panels and core. The results of research showed that the method of manufacturing, more precisely the pressure while forming sandwich panels, influences some mechanical properties of sandwich structured polymer composites such as flexural strength, impact strength, and compressive strength.

  3. A novel indirect ELISA for diagnosis of dengue fever.

    Science.gov (United States)

    Narayan, Rohan; Raja, Senthil; Kumar, Senthil; Sambasivam, Mohana; Jagadeesan, Raja; Arunagiri, Kavita; Krishnasamy, Kaveri; Palani, Gunasekaran

    2016-07-01

    Dengue fever (DF) is associated with significant morbidity and mortality in the tropical and sub-tropical regions of the world. Since there are no effective antiviral drugs for treatment, clinicians often rely on the accurate diagnosis of dengue fever to begin supportive therapy at early stages of the illness. The objective of this study was to develop an in-house dengue virus serotype 2 (DENV-2) non-structural protein- 5 (NS5) based indirect ELISA. DENV-2 was raised in Vero cells and the viral proteins were separated and subsequently the NS5 protein was eluted. Serum samples from primary and secondary dengue fever patients; and acute and convalescent samples from Japanese encephalitis (JE) and West Nile virus (WNV) cases were used to validate the ELISA. The assay was found to be 100 per cent specific in detecting DENV-2 specific antibodies from patient's serum. However, in terms of sensitivity, the assay could detect IgM antibodies only from 90 per cent of the primary dengue samples. The IgM/IgG ratio of the primary and secondary samples was 7.24 and 0.64, respectively. The results indicate that the DENV-2 NS5 ELISA is dengue group specific and can be used to differentiate dengue infection from other circulating Flavivirus infections. This NS5 ELISA can also be used to distinguish between primary and secondary dengue fever on the basis of IgM/IgG ratios. Further studies with larger sample sizes and different DENV serotypes are required to validate the ELISA.

  4. A novel indirect ELISA for diagnosis of dengue fever

    Directory of Open Access Journals (Sweden)

    Rohan Narayan

    2016-01-01

    Full Text Available Background & objectives: Dengue fever (DF is associated with significant morbidity and mortality in the tropical and sub-tropical regions of the world. Since there are no effective antiviral drugs for treatment, clinicians often rely on the accurate diagnosis of dengue fever to begin supportive therapy at early stages of the illness. The objective of this study was to develop an in-house dengue virus serotype 2 (DENV-2 non-structural protein- 5 (NS5 based indirect ELISA. Methods: DENV-2 was raised in Vero cells and the viral proteins were separated and subsequently the NS5 protein was eluted. Serum samples from primary and secondary dengue fever patients; and acute and convalescent samples from Japanese encephalitis (JE and West Nile virus (WNV cases were used to validate the ELISA. Results: The assay was found to be 100 per cent specific in detecting DENV-2 specific antibodies from patient′s serum. However, in terms of sensitivity, the assay could detect IgM antibodies only from 90 per cent of the primary dengue samples. The IgM/IgG ratio of the primary and secondary samples was 7.24 and 0.64, respectively. Interpretation & conclusions: The results indicate that the DENV-2 NS5 ELISA is dengue group specific and can be used to differentiate dengue infection from other circulating Flavivirus infections. This NS5 ELISA can also be used to distinguish between primary and secondary dengue fever on the basis of IgM/IgG ratios. Further studies with larger sample sizes and different DENV serotypes are required to validate the ELISA.

  5. Sandwich-structured hollow fiber membranes for osmotic power generation

    KAUST Repository

    Fu, Feng Jiang

    2015-11-01

    In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

  6. Sandwiched Rényi divergence satisfies data processing inequality

    Energy Technology Data Exchange (ETDEWEB)

    Beigi, Salman [School of Mathematics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5746, Tehran (Iran, Islamic Republic of)

    2013-12-15

    Sandwiched (quantum) α-Rényi divergence has been recently defined in the independent works of Wilde et al. [“Strong converse for the classical capacity of entanglement-breaking channels,” preprint http://arxiv.org/abs/arXiv:1306.1586 (2013)] and Müller-Lennert et al. [“On quantum Rényi entropies: a new definition, some properties and several conjectures,” preprint http://arxiv.org/abs/arXiv:1306.3142v1 (2013)]. This new quantum divergence has already found applications in quantum information theory. Here we further investigate properties of this new quantum divergence. In particular, we show that sandwiched α-Rényi divergence satisfies the data processing inequality for all values of α > 1. Moreover we prove that α-Holevo information, a variant of Holevo information defined in terms of sandwiched α-Rényi divergence, is super-additive. Our results are based on Hölder's inequality, the Riesz-Thorin theorem and ideas from the theory of complex interpolation. We also employ Sion's minimax theorem.

  7. Static and Fatigue Characterization of Nomex Honeycomb Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Keskes Boualem

    2013-07-01

    Full Text Available The main benefits of using the sandwich concept in structural components are the high stiffness, good fatigue resistance and low weight ratios. Recent advances in materials and construction techniques have resulted in further improvement and increased uniformity of the sandwich composite properties. In order to use these materials in different applications, the knowledge of simply their static properties alone is not sufficient but additional information on their fatigue properties and durability are required. In this paper, first static and fatigue tests on four points bending of nomex honeycomb composite sandwich panels have been performed. Load/displacement and S-N fatigue curves are presented and analysed. Fatigue failure and damage modes are observed with an optical microscope and are discussed. The second is to address such fatigue behaviour by using a damage model and check it by experimentation. This fatigue damage model is based on stiffness degradation, which is used as a damage indicator. Two non-linear cumulative damage models derived from the chosen stiffness degradation equation are examined with assumption of linear Miner's damage summation. Predicted results are compared with available experimental data.

  8. Structural modeling of sandwich structures with lightweight cellular cores

    Science.gov (United States)

    Liu, T.; Deng, Z. C.; Lu, T. J.

    2007-10-01

    An effective single layered finite element (FE) computational model is proposed to predict the structural behavior of lightweight sandwich panels having two dimensional (2D) prismatic or three dimensional (3D) truss cores. Three different types of cellular core topology are considered: pyramidal truss core (3D), Kagome truss core (3D) and corrugated core (2D), representing three kinds of material anisotropy: orthotropic, monoclinic and general anisotropic. A homogenization technique is developed to obtain the homogenized macroscopic stiffness properties of the cellular core. In comparison with the results obtained by using detailed FE model, the single layered computational model can give acceptable predictions for both the static and dynamic behaviors of orthotropic truss core sandwich panels. However, for non-orthotropic 3D truss cores, the predictions are not so well. For both static and dynamic behaviors of a 2D corrugated core sandwich panel, the predictions derived by the single layered computational model is generally acceptable when the size of the unit cell varies within a certain range, with the predictions for moderately strong or strong corrugated cores more accurate than those for weak cores.

  9. Size Effects in Impact Damage of Composite Sandwich Panels

    Science.gov (United States)

    Dobyns, Alan; Jackson, Wade

    2003-01-01

    Panel size has a large effect on the impact response and resultant damage level of honeycomb sandwich panels. It has been observed during impact testing that panels of the same design but different panel sizes will show large differences in damage when impacted with the same impact energy. To study this effect, a test program was conducted with instrumented impact testing of three different sizes of sandwich panels to obtain data on panel response and residual damage. In concert with the test program. a closed form analysis method was developed that incorporates the effects of damage on the impact response. This analysis method will predict both the impact response and the residual damage of a simply-supported sandwich panel impacted at any position on the panel. The damage is incorporated by the use of an experimental load-indentation curve obtained for the face-sheet/honeycomb and indentor combination under study. This curve inherently includes the damage response and can be obtained quasi-statically from a rigidly-backed specimen or a specimen with any support conditions. Good correlation has been obtained between the test data and the analysis results for the maximum force and residual indentation. The predictions can be improved by using a dynamic indentation curve. Analyses have also been done using the MSC/DYTRAN finite element code.

  10. Microtomography with a sandwich detector for mouse bone imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ho; Kim, Junwoo; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of); Youn, Hanbean; Jeon, Hosang [Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of)

    2015-10-15

    Single-shot dual-energy imaging, using sandwich detector, the rear detector usually uses a thicker x-ray converter to enhance quantum efficiency with the higher-energy spectrum, hence providing a blurrier image than the front detector. The weighted logarithmic subtraction of the two images therefore results in a form of unsharp masking that enhances edges in the resultant image. Inspired by this observation, we have developed a micro computed tomography (micro-CT) system with the sandwich detector for high-resolution bone imaging of small animals. The sandwich detector consists of two flat-panel detectors by stacking one upon the other. Although the x-ray beam continuously irradiates, the step-rotation of an object and stay-readout of projection data were considered for the scanning and data gathering. It will be necessary that more elaborate experiments with the mouse and/or other quantitative phantoms. And quantification of the image quality of bone-enhanced images in comparisons with the conventional images will be performed. The image analysis of differences between bone-enhanced images obtained from the projection- and image-based approaches can be performed.

  11. Static and Fatigue Characterization of Nomex Honeycomb Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Keskes Boualem

    2013-07-01

    Full Text Available The main benefits of using the sandwich concept in structural components are the high stiffness, good fatigue resistance and low weight ratios. Recent advances in materials and construction techniques have resulted in further improvement and increased uniformity of the sandwich composite properties. In order to use these materials in different applications, the knowledge of simply their static properties alone is not sufficient but additional information on their fatigue properties and durability are required. In this paper, first static and fatigue tests on four points bending of nomex honeycomb composite sandwich panels have been performed. Load/displacement and S-N fatigue curves are presented and analysed. Fatigue failure and damage modes are observed with an optical microscope and are discussed. The second is to address such fatigue behaviour by using a damage model and check it by experimentation. This fatigue damage model is based on stiffness degradation, which is used as a damage indicator. Two non-linear cumulative damage models derived from the chosen stiffness degradation equation are examined with assumption of linear Miner's damage summation. Predicted results are compared with available experimental data.

  12. Systematic selection of modified aptamer pairs for diagnostic sandwich assays.

    Science.gov (United States)

    Ochsner, Urs A; Green, Louis S; Gold, Larry; Janjic, Nebojsa

    2014-01-01

    Protein diagnostic applications typically require pairs of analyte-specific reagents for capture and detection. We developed methods for the systematic isolation of slow off-rate modified aptamer (SOMAmer) reagents that bind to different epitopes and allow efficient pair-wise screening of multiple ligands. SOMAmers were generated via a second systematic evolution of ligands by exponential enrichment (SELEX), using complexes of target proteins with a primary, non-amplifiable SOMAmer and employing different modified nucleotides (e.g., naphthylmethyl- or tryptaminocarbonyl-dU) to favor alternate binding epitopes. Non-competing binding of primary and secondary SOMAmers was tested in radiolabel competition and sandwich binding assays. Multiplexed high-throughput screening for sandwich pairs utilized the Luminex platform, with primary SOMAmers as capture agents attached to different types of LumAvidin beads, which were then pooled for testing the secondary SOMAmers individually as detection agents. Functional SOMAmer pairs were obtained for Clostridium difficile binary toxin (CdtA) and for a panel of human proteins (ANGPT2, TSP2, CRDL1, MATN2, GPVI, C7, PLG) that had been previously identified as promising markers for cardiovascular risk. The equilibrium dissociation constants (Kd values) ranged from 0.02-2.7 nM, and the detection limits were in the low picomolar range for these proteins in SOMAmer sandwich assays. These results indicate that SOMAmer pairs hold promise for the development of rapid tests or specific diagnostic panels.

  13. Structural modeling of sandwich structures with lightweight cellular cores

    Institute of Scientific and Technical Information of China (English)

    T. Liu; Z. C. Deng; T. J. Lu

    2007-01-01

    An effective single layered finite element (FE) computational model is proposed to predict the structural behavior of lightweight sandwich panels having two dimensional (2D) prismatic or three dimensional (3D) truss cores.Three different types of cellular core topology are considered: pyramidal truss core (3D), Kagome truss core (3D) and corrugated core (2D), representing three kinds of material anisotropy: orthotropic, monoclinic and general anisotropic. A homogenization technique is developed to obtain the homogenized macroscopic stiffness properties of the cellular core. In comparison with the results obtained by using detailed FE model, the single layered computational model cangive acceptable predictions for both the static and dynamic behaviors of orthotropic truss core sandwich panels. However, for non-orthotropic 3D truss cores, the predictions are not so well. For both static and dynamic behaviors of a 2D corrugated core sandwich panel, the predictions derived by the single layered computational model is generally acceptable when the size of the unit cell varies within a certain range, with the predictions for moderately strong or strong corrugated cores more accurate than those for weak cores.

  14. Improving the performance of dye-sensitized solar cells with TiO2/graphene/TiO2 sandwich structure.

    Science.gov (United States)

    Chen, Lung-Chien; Hsu, Chih-Hung; Chan, Po-Shun; Zhang, Xiuyu; Huang, Cing-Jhih

    2014-01-01

    This study investigates the extent to which the TiO2/graphene/TiO2 sandwich structure improves the performance of dye-sensitized solar cells (DSSCs) over that of DSSCs with the traditional structure. Studies have demonstrated that the TiO2/graphene/TiO2 sandwich structure effectively enhances the open circuit voltage (V oc), short-circuit current density (J sc), and photoelectrical conversion efficiency (η) of DSSCs. The enhanced performance of DSSCs with the sandwich structure can be attributed to an increase in electron transport efficiency and in the absorption of light in the visible range. The DSSC with the sandwich structure in this study exhibited a V oc of 0.6 V, a high J sc of 11.22 mA cm(-2), a fill factor (FF) of 0.58, and a calculated η of 3.93%, which is 60% higher than that of a DSSC with the traditional structure.

  15. Self-assembly of 2D sandwich-structured MnFe{sub 2}O{sub 4}/graphene composites for high-performance lithium storage

    Energy Technology Data Exchange (ETDEWEB)

    Li, Songmei, E-mail: songmei_li@buaa.edu.cn; Wang, Bo; Li, Bin; Liu, Jianhua; Yu, Mei; Wu, Xiaoyu

    2015-01-15

    Highlights: • MFO/GN composites were synthesized by a facile in situ solvothermal approach. • The MFO microspheres are sandwiched between the graphene layers. • Each MFO microsphere is an interstitial cluster of nanoparticles. • The MFO/GN electrode exhibits an enhanced cyclability for Li-ion batteries anodes. - Abstract: In this study, two-dimensional (2D) sandwich-structured MnFe{sub 2}O{sub 4}/graphene (MFO/GN) composites are synthesized by a facile in situ solvothermal approach, using cetyltrimethylammonium bromide (CTAB) as cationic surfactant. As a consequence, the nanocomposites of MFO/GN self-assembled into a 2D sandwich structure, in which the interstitial cluster structure of microsphere-type MnFe{sub 2}O{sub 4} is sandwiched between the graphene layers. This special structure of the MFO/GN composites used as anodes for lithium-ion batteries will be favorable for the maximum accessible surface of electroactive materials, fast diffusion of lithium ions and migration of electron, and elastomeric space to accommodate volume changes during the discharge–charge processes. The as-synthesized MFO/GN composites deliver a high specific reversible capacity of 987.95 mA h g{sup −1} at a current density of 200 mA g{sup −1}, a good capacity retention of 69.27% after 80 cycles and excellent rate performance for lithium storage.

  16. Sex-specific and inter-individual differences in biomarkers of selenium status identified by a calibrated ELISA for selenoprotein P

    Directory of Open Access Journals (Sweden)

    Sandra Hybsier

    2017-04-01

    Full Text Available Selenoprotein P (SELENOP is a liver-derived transporter of selenium (Se in blood, and a meaningful biomarker of Se status. Se is an essential trace element for the biosynthesis of enzymatically-active selenoproteins, protecting the organism from oxidative damage. The usage of uncalibrated assays hinders the comparability of SELENOP concentrations and their pathophysiological interpretation across different clinical studies. On this account, we established a new sandwich SELENOP-ELISA and calibrated against a standard reference material (SRM1950. The ELISA displays a wide working range (11.6–538.4 µg/L, high accuracy (2.9% and good precision (9.3%. To verify whether SELENOP correlates to total Se and to SELENOP-bound Se, serum samples from healthy subjects and age-selected participants from the Berlin Aging Study II were analyzed by SELENOP-ELISA and Se quantification. SELENOP was affinity-purified and its Se content was determined from a subset of samples. There was a high correlation of total Se and SELENOP concentrations in young and elderly men, and in elderly women, but not in young women, indicating a specific sexual dimorphism in these biomarkers of Se status in young subjects. The Se content of isolated SELENOP was independent of sex and age (mean±SD: 5.4±0.5. By using this calibrated SELENOP-ELISA, prior reports on pathological SELENOP concentrations in diabetes and obesity are challenged as the reported values are outside reasonable limits. Biomarkers of Se status in clinical research need to be measured by validated assays in order to avoid erroneous data and incorrect interpretations, especially when analyzing young women. The Se content of circulating SELENOP differs between individuals and may provide some important diagnostic information on Se metabolism and status.

  17. Data characterizing compressive properties of Al/Al2O3 syntactic foam core metal matrix sandwich

    Directory of Open Access Journals (Sweden)

    Mohammed Yaseer Omar

    2015-12-01

    Full Text Available Microstructural observations and compressive property datasets of metal matrix syntactic foam core sandwich composite at quasi-static and high strain rate (HSR conditions (525–845 s−1 are provided. The data supplied in this article includes sample preparation procedure prior to scanning electron and optical microscopy as well as the micrographs. The data used to construct the stress–strain curves and the derived compressive properties of all specimens in both quasi-static and HSR regions are included. Videos of quasi-static compressive failure and that obtained by a high speed image acquisition system during deformation and failure of HSR specimen are also included.

  18. Effect of strain on the critical current density of Bi-2223 thick films sandwiched between Ag sheets

    Energy Technology Data Exchange (ETDEWEB)

    Jia, J.H. (Academia Sinica, Hefei (China). Inst. of Solid State Physics); Kong, Q.P. (Academia Sinica, Hefei (China). Inst. of Solid State Physics); Wang, S.X. (Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics); Han, H.M. (Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics)

    1994-08-16

    The tapes of (Bi, Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x] (Bi-2223) thick film sandwiched between Ag sheets are known to have very high J[sub c]. In this note, the stress-strain behaviour and the strain dependence of critical current density of the Ag/Bi-2223/Ag tapes are investigated. The microstructure of superconducting thick films subjected to various amounts of deformation was examined with a scanning electron microscope (SEM). (orig.)

  19. Cooling Shelf For Electronic Equipment

    Science.gov (United States)

    Tanzer, Herbert J.

    1989-01-01

    Heat-pipe action cools and maintains electronics at nearly constant temperature. System designed to control temperatures of spacecraft shelves or baseplates by combining honeycomb sandwich panel with reservoir of noncondensable gas and processing resulting device as variable-conductance heat pipe. Device provides flat surface for mounting heat-dissipating electronics that is effectively cooled and maintained at nearly constant temperature. Potentially useful in freeze drying, refrigeration, and air conditioning.

  20. E.L.I.S.A. en coccidioidomicosis humana E.L.I.S.A. in human coccidioidomycosis

    Directory of Open Access Journals (Sweden)

    Iris Nora Tiraboschi

    1991-08-01

    Full Text Available Se realizó E.L.I.S.A. con exoantígeno de Coccidioides immitis para la detectión de anticuerpos, en 67 sueros humanos diluidos 1/1000, 1/2000, 1/4000 y 1/8000. De los 18 sueros de enfermos de coccidioidomicosis comprobada por examen directo, cultivo y/o histología, 5 fueron negativos, en otros 13 fueron positivos en una o varias diluciones. 3/26 sueros de personas sanas, coccidioidino positivas, fueron positivos en títulos de 1/1000 y el resto no tuvo anticuerpos detectables. No presentaron reacciones positivas ninguno de los sueros controles de personas sanas, pero sí lo hicieron 4/8 pacientes con otras micosis. Se concluye que E.L.I.S.A. es útil para la detección de mínimas cantidades de anticuerpos o en sueros que no pueden ser procesados por fijación de complemento. No es recomendable el uso de la técnica en forma aislada por al presencia de reacciones cruzadas.An E.L.I.S.A. test for antibody detection, with an exo-antigen of Coccidioides immitis was standardized in 67 humans sera diluited in 1/1000, 1/2000, 1/4000 and 1/8000. Eightheen sera from mycologically proved cases of coccidioidomycosis were studied: 5 were negative and 13 were positive in some dilutions. 3/26 sera of healthy persons who presented positive skin tests with coccidioidin were positive and the other 23 sera did not have positive reactions. None of the 15 sera of healthy human exhibited positive E.L.I.S.A. Serum samples of 8 patients suffering other deep mycosis were studied, 4 of them presented cross-reactions in E.L.I.S.A. tests. E.L.I.S.A. test seems to be a useful Serologic technique for antibody detection in anticomplementary serum samples or when a low concentration of antibodies should be detected. As it is very sensitive, cross-reactions with other mycoses are frequent, thus the use other more specific serologic technique together E.L.I.S.A. is recommended.