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Sample records for antibody-based sandwich elisa

  1. 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.

  2. Evaluation of monoclonal antibody-based sandwich direct ELISA (MSD-ELISA for antigen detection of foot-and-mouth disease virus using clinical samples.

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    Kazuki Morioka

    Full Text Available A monoclonal antibody-based sandwich direct ELISA (MSD-ELISA method was previously developed for foot-and-mouth disease (FMD viral antigen detection. Here we evaluated the sensitivity and specificity of two FMD viral antigen detection MSD-ELISAs and compared them with conventional indirect sandwich (IS-ELISA. The MSD-ELISAs were able to detect the antigen in saliva samples of experimentally-infected pigs for a longer term compared to the IS-ELISA. We also used 178 RT-PCR-positive field samples from cattle and pigs affected by the 2010 type-O FMD outbreak in Japan, and we found that the sensitivities of both MSD-ELISAs were about 7 times higher than that of the IS-ELISA against each sample (P<0.01. In terms of the FMD-positive farm detection rate, the sensitivities of the MSD-ELISAs were about 6 times higher than that of the IS-ELISA against each farm (P<0.01. Although it is necessary to conduct further validation study using the other virus strains, MSD-ELISAs could be appropriate as a method to replace IS-ELISA for FMD antigen detection.

  3. Evaluation of monoclonal antibody-based sandwich direct ELISA (MSD-ELISA) for antigen detection of foot-and-mouth disease virus using clinical samples.

    Science.gov (United States)

    Morioka, Kazuki; Fukai, Katsuhiko; Sakamoto, Kenichi; Yoshida, Kazuo; Kanno, Toru

    2014-01-01

    A monoclonal antibody-based sandwich direct ELISA (MSD-ELISA) method was previously developed for foot-and-mouth disease (FMD) viral antigen detection. Here we evaluated the sensitivity and specificity of two FMD viral antigen detection MSD-ELISAs and compared them with conventional indirect sandwich (IS)-ELISA. The MSD-ELISAs were able to detect the antigen in saliva samples of experimentally-infected pigs for a longer term compared to the IS-ELISA. We also used 178 RT-PCR-positive field samples from cattle and pigs affected by the 2010 type-O FMD outbreak in Japan, and we found that the sensitivities of both MSD-ELISAs were about 7 times higher than that of the IS-ELISA against each sample (P<0.01). In terms of the FMD-positive farm detection rate, the sensitivities of the MSD-ELISAs were about 6 times higher than that of the IS-ELISA against each farm (P<0.01). Although it is necessary to conduct further validation study using the other virus strains, MSD-ELISAs could be appropriate as a method to replace IS-ELISA for FMD antigen detection.

  4. Immunodiagnostic monoclonal antibody-based sandwich ELISA of fasciolosis by detection of Fasciola gigantica circulating fatty acid binding protein.

    Science.gov (United States)

    Anuracpreeda, Panat; Chawengkirttikul, Runglawan; Sobhon, Prasert

    2016-09-01

    Up to now, parasitological diagnosis of fasciolosis is often unreliable and possesses low sensitivity. Hence, the detection of circulating parasite antigens is thought to be a better alternative for diagnosis of fasciolosis, as it reflects the real parasite burden. In the present study, a monoclonal antibody (MoAb) against recombinant Fasciola gigantica fatty acid binding protein (rFgFABP) has been produced. As well, a reliable sandwich enzyme-linked immunosorbent assay (sandwich ELISA) has been developed for the detection of circulating FABP in the sera of mice experimentally and cattle naturally infected with F. gigantica. MoAb 3A3 and biotinylated rabbit anti-recombinant FABP antibody were selected due to their high reactivities and specificities. The lower detection limit of sandwich ELISA was 5 pg mL-1, and no cross-reaction with other parasite antigens was observed. This assay could detect F. gigantica infection from day 1 post infection. In experimental mice, the sensitivity, specificity and accuracy of this assay were 93·3, 100 and 98·2%, while in natural cattle they were 96·7, 100 and 99·1%. Hence, this sandwich ELISA method showed high efficiencies and precisions for diagnosis of fasciolosis by F. gigantica.

  5. Development of a Monoclonal Antibody-Based Sandwich ELISA for Peanut Allergen Ara h 1 in Food

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    Chuanlai Xu

    2013-07-01

    Full Text Available We have established a highly sensitive sandwich enzyme-linked immunosorbent assay (ELISA based on two monoclonal antibodies (mAb to measure the content of the major peanut allergen Ara h 1 in foods. Two mAbs were selected out of 12 murine hybridoma cells secreting Ara h 1-specific antibody. Using mAb 6 as the capture antibody and HRP-labelled mAb 4 as the detection antibody, the limit of detection (LOD the assay was 0.34 ng/mL. Cross-reaction analysis showed that this method was strongly specific and had no cross-reactions with Ara h 2, pea protein or soy protein. Sample analysis showed that this ELISA was a useful tool to monitor peanut allergens in food products by measuring Ara h 1 content.

  6. Quantification in mass units of group 1 grass allergens by a monoclonal antibody-based sandwich ELISA.

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    Arilla, M C; Ibarrola, I; Eraso, E; Aguirre, M; Martínez, A; Asturias, J A

    2001-08-01

    Grass pollen extracts currently used for allergy diagnosis and immunotherapy are a complex mixture of proteins of which only a few have allergenic activity. Lol p 1 is one of the most important allergens in grass pollen extracts. To develop a two-site enzyme-linked immunosorbent assay for the quantification of Lol p 1 and other group 1 allergens from grass species, and to assess its suitability for quantifying this group of allergens. Balb/c mice immunized with recombinant Lol p 1 were used for the production of monoclonal antibodies. Screening of hybridomas was performed by direct ELISA, and selected monoclonal antibodies were immobilized on ELISA plates and incubated with samples containing group 1 allergens. Bound allergens were detected by a combination of biotinylated Lol p 1-specific monoclonal antibody and peroxidase-streptavidin conjugate. The assay is based on three Lol p 1-specific monoclonal antibodies with different epitope specificities. The optimized ELISA measured Lol p 1 concentrations ranging from 125 to 1000 ng/mL and could quantify group 1 allergen from grass species belonging to the Pooidea subfamily. The assay does not depend on anti-sera production or availability of human sera and thus reactives can be produced in unlimited amounts. This sensitive and specific Lol p 1 assay will be helpful both for quantifying the group 1 allergen content of Pooideae pollen extracts intended for clinical use and for studying cross-reactivities among pollen extracts.

  7. Immunodiagnosis of Fasciola gigantica Infection Using Monoclonal Antibody-Based Sandwich ELISA and Immunochromatographic Assay for Detection of Circulating Cathepsin L1 Protease.

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    Anuracpreeda, Panat; Chawengkirttikul, Runglawan; Sobhon, Prasert

    2016-01-01

    Tropical fasciolosis caused by Fasciola gigantica infection is one of the major diseases infecting ruminants in the tropical regions of Africa and Asia including Thailand. Parasitological diagnosis of fasciolosis is often unreliable and possesses low sensitivity. Therefore, the detection of circulating parasite antigens is thought to be a better alternative for diagnosis of fasciolosis, as it reflects the real parasite burden. In this study, we have produced a monoclonal antibody (MoAb) against recombinant F. gigantica cathepsin L1 (rFgCatL1), and developed both sandwich enzyme-linked immunosorbent assay (sandwich ELISA) and immunochromatographic (IC) test for rapid detection of circulating cathepsin L1 protease (CatL1) in the sera from mice experimentally and cattle naturally infected with Fasciola gigantica. MoAb 4E3 and biotinylated rabbit anti-recombinant CatL1 antibody were selected due to their high reactivities and specificities. The lower detection limits of sandwich ELISA and IC test were 3 pg/ml and 0.256 ng/ml, respectively. Sandwich ELISA and IC test could detect F. gigantica infection from day 1 to 35 post infection. In experimental mice, the sensitivity, specificity and accuracy were 95%, 100% and 98.6% (for sandwich ELISA), and 93%, 100% and 98.2% (for IC test), while in natural cattle they were 98.3%, 100% and 99.5% (for sandwich ELISA), and 96.7%, 100% and 99.1% (for IC test). These two assay methods showed high efficiencies and precisions for diagnosis of fasciolosis by F. gigantica.

  8. Immunodiagnosis of Fasciola gigantica Infection Using Monoclonal Antibody-Based Sandwich ELISA and Immunochromatographic Assay for Detection of Circulating Cathepsin L1 Protease

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    Anuracpreeda, Panat; Chawengkirttikul, Runglawan; Sobhon, Prasert

    2016-01-01

    Background Tropical fasciolosis caused by Fasciola gigantica infection is one of the major diseases infecting ruminants in the tropical regions of Africa and Asia including Thailand. Parasitological diagnosis of fasciolosis is often unreliable and possesses low sensitivity. Therefore, the detection of circulating parasite antigens is thought to be a better alternative for diagnosis of fasciolosis, as it reflects the real parasite burden. Methods In this study, we have produced a monoclonal antibody (MoAb) against recombinant F. gigantica cathepsin L1 (rFgCatL1), and developed both sandwich enzyme-linked immunosorbent assay (sandwich ELISA) and immunochromatographic (IC) test for rapid detection of circulating cathepsin L1 protease (CatL1) in the sera from mice experimentally and cattle naturally infected with Fasciola gigantica. MoAb 4E3 and biotinylated rabbit anti-recombinant CatL1 antibody were selected due to their high reactivities and specificities. Results The lower detection limits of sandwich ELISA and IC test were 3 pg/ml and 0.256 ng/ml, respectively. Sandwich ELISA and IC test could detect F. gigantica infection from day 1 to 35 post infection. In experimental mice, the sensitivity, specificity and accuracy were 95%, 100% and 98.6% (for sandwich ELISA), and 93%, 100% and 98.2% (for IC test), while in natural cattle they were 98.3%, 100% and 99.5% (for sandwich ELISA), and 96.7%, 100% and 99.1% (for IC test). Conclusions These two assay methods showed high efficiencies and precisions for diagnosis of fasciolosis by F. gigantica. PMID:26731402

  9. Detection of Human Epididymis Protein 4 (HE4) in Human Serum Samples Using a Specific Monoclonal Antibody-Based Sandwich Enzyme-Linked Immunosorbent Assay (ELISA).

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    Zhou, Lijun; Lv, Zhiqiang; Shao, Jing; Xu, Ying; Luo, Xiaohong; Zhang, Yuming; Hu, Yang; Zhang, Wenji; Luo, Shuhong; Fang, Jianmin; Wang, Ying; Duan, Chaohui; Huang, Ruopan

    2016-09-01

    The human epididymis protein 4 (HE4) may have high specificity in the detection of malignant diseases, making the development of an immunoassay for HE4 essential. In our study, a fusion gene was constructed encoded with the HE4 protein. This protein was then produced in the bacterial cells (Escherichia coli) and used to immunize mice in order to eventually generate hybridomas specific to HE4. The hybridoma supernatants were then screened, and four positive anti-HE4 cell lines were selected. These cell lines produce monoclonal antibodies against HE4 epitopes, as demonstrated in the Western blot as well as by direct enzyme-linked immunosorbent assay (ELISA). Using the developed antibodies, we successfully identified several good antibody pairs from the hybridomas, which allowed for the development of a sandwich ELISA to measure HE4 levels. By using the HE4 ELISA, we measured HE4 levels of 60 clinical human serum samples. Compared with the Food and Drug Administration (FDA) approved kit (Roche), our results showed a strong positive correlation to those of the FDA-approved kit. In summary, highly sensitive antibody pairs were screened against HE4, and a sandwich ELISA was developed as an accurate analytical tool for the detection of HE4 in human serum, which could be especially valuable for diagnosing ovarian carcinomas. © 2015 Wiley Periodicals, Inc.

  10. 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

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    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.

  11. Development of a monoclonal antibody-based sandwich-type enzyme-linked immunosorbent assay (ELISA) for detection of abrin in food samples.

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    Zhou, Yu; Tian, Xiang-Li; Li, Yan-Song; Pan, Feng-Guang; Zhang, Yuan-Yuan; Zhang, Jun-Hui; Wang, Xin-Rui; Ren, Hong-Lin; Lu, Shi-Ying; Li, Zhao-Hui; Liu, Zeng-Shan; Chen, Qi-Jun; Liu, Jing-Qiu

    2012-12-15

    Abrin is a plant toxin, which can be easily isolated from the seeds of Abrus precatorius. It may be used as a biological warfare agent. In order to detect abrin in food samples, a two-layer sandwich format enzyme-linked immunosorbent assay based on the monoclonal antibody (mAb) (as capture antibody) and rabbit polyclonal serum (as detecting antibody) was developed and applied for the determination of abrin in some food matrices. The linear range of the mAb was 1-100 μg L(-1) with a detection limit of 0.5 μg L(-1) for abrin in phosphate buffered saline (PBS). The recoveries of abrin from sausage, beer and milk samples ranged 97.5-98.6%, 95.8-98.4% and 94.8-9.6%, respectively, with a coefficient of variation (CV) of 3.7% or less. The newly developed sandwich ELISA using the mAb appears to be a reliable and useful method for detection of abrin in sausage, beer and milk. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Hyperglucagonaemia analysed by glucagon sandwich ELISA

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... sensitivity for glucagon in plasma (>10-20 pmol/l). Thus, only the third assay was suitable for measuring glucagon concentrations in clinical samples. The ELISA and RIA measured similar glucagon levels in healthy individuals. Measurements of samples from individuals with abnormally high (type 2 diabetes...... or obese) or very elevated (post vagotomy with pyloroplasty, post-RYGB) glucagon levels were also similar in both assays. However, glucagon levels in participants with ESRD were much lower when measured by ELISA than by RIA, indicating that the apparent hyperglucagonaemia is not caused by fully processed...

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

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

    2017-10-01

    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 almond, limit of quantification almond), specificity (no cross-reactivity with 156 tested foods at a concentration of 100000 ppm whole sample), and reproducibility (intra- and interassay variability 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. Ability to detect and quantify trace amounts of almonds is important for improving safety of almond sensitive consumers. Two monoclonal antibody-based ELISAs were compared for almond detection. The information is useful to food industry, regulatory agencies, scientific community, and almond consumers. © 2017 Institute of Food Technologists®.

  14. Quantitative sandwich ELISA for the determination of fish in foods.

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    Faeste, Christiane K; Plassen, Christin

    2008-01-01

    Allergy to fish represents one of the most prevalent causes for severe food-allergic reactions. Therefore, food authorities in different countries have implemented mandatory labeling of fish in pre-packed foods. Detection of fish proteins in food has previously been based on the use of patient serum. In the present study, a novel sandwich enzyme-linked immunosorbent assay (ELISA) for the quantitation of fish in food matrixes has been developed and validated, using a polyclonal rabbit anti-cod parvalbumin antibody for capture and a biotinylated conjugate of the same antibody for detection. By employing the ubiquitous muscle protein parvalbumin as target the method succeeds to detect a variety of fish. However, the ELISA is specific for fish and does not cross-react with other species. Recoveries ranged from 68-138% in typical food matrixes, while the intra- and inter-assay precisions were parvalbumin ELISA with a limit of detection of 0.01 mg parvalbumin/kg food, about 5 mg fish/kg food, seems sufficient to detect fish protein traces in foods at levels low enough to minimize the risk for fish allergic consumers.

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

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    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.

  16. A monoclonal antibody based capture ELISA for botulinum neurotoxin serotype B: toxin detection in food.

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    Stanker, Larry H; Scotcher, Miles C; Cheng, Luisa; Ching, Kathryn; McGarvey, Jeffery; Hodge, David; Hnasko, Robert

    2013-11-18

    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.

  17. ELISA with double antigen sandwich for screening specific serum anti-TP antibody in blood donors

    International Nuclear Information System (INIS)

    Wang Yiqing; Shi Zhixu

    2002-01-01

    Objective: To select a sensitive and specific laboratory examination suitable for screening serum anti-TP antibody in blood donors. Methods: The serum anti-TP antibody in 11271 blood donors were detected using ELISA with double antigen sandwich and the outcomes were compared with those using RPR assay. The conflicting specimen were confirmed by repeating the test with TPHA assay. Results: The positive rates of serum anti-TP antibody by ELISA with double antigen sandwich and RPR was 0.36% (41/11271) and 0.26% (29/11271), respectively. The coincidence of the detecting outcomes by ELISA with double antigen sandwich and RPR with TPHA was 97.5% (40/41) and 63.41%(26/41) respectively. Conclusion: Compared with RPR assay, ELISA with double antigen sandwich has higher sensibility and specificity for screening serum anti-TP antibody in blood donors

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

    DEFF Research Database (Denmark)

    Wewer Albrechtsen, Nicolai J; Asmar, Ali; Jensen, Frederik

    2017-01-01

    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...

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  20. [A double antibody sandwich ELISA based assay for titration of severe fever with thrombocytopenia syndrome virus].

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    Liu, Lin; Zhang, Quan-Fu; Li, Chuan; Li, Jian-Dong; Jiang, Xiao-Lin; Zhang, Fu-Shun; Wu, Wei; Liang, Mi-Fang; Li, De-Xin

    2013-06-01

    To develop an assay for titration of severe fever with thrombocytopenia syndrome virus (SFTSV) based on double antibody sandwich ELISA. A double antibody sandwich ELISA was developed for detection of SFTSV based on SFTSV nucleocapsid (N) protein specific poly- and monoclonal antibodies, procedures were optimized and evaluated. This ELISA based titration assay was compared with fluorescence assasy and plaque assay based titration method. The results suggested that the titers obtained by ELISA based method are consistent with those obtained by IFA based method (R = 0.999) and the plaque assay titration method (R = 0.949). The novel ELISA based titration method with high sensitivity and specificity is easy to manage and perform, and can overcome the subjectivity associated with result determination of the fluorescence assay and plaque assay based methods. The novel ELISA based titration method can also be applied to high throughput detection.

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

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    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.

  2. A Monoclonal Antibody-Based ELISA for Multiresidue Determination of Avermectins in Milk

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    Wenxiao Jiang

    2012-06-01

    Full Text Available Due to the widespread use and potential toxicity of avermectins (AVMs, multi-residue monitoring of AVMs in edible tissues, especially in milk, has become increasingly important. With the aim of developing a broad-selective immunoassay for AVMs, a broad-specific monoclonal antibody (Mab was raised. Based on this Mab, a homologous indirect enzyme-linked immunosorbent assay (ELISA for the rapid detection of AVMs in milk was developed. Under the optimized conditions, the IC50 values in assay buffer were estimated to be 3.05 ng/mL for abamectin, 13.10 ng/mL for ivermectin, 38.96 ng/mL for eprinomectin, 61.00 ng/mL for doramectin, 14.38 ng/mL for emamectin benzoate. Detection capability (CCβ of the ELISA was less than 5 ng/mL and 2 ng/mL in milk samples prepared by simple dilution and solvent extraction, respectively. The optimized ELISA was used to quantify AVMs in milk samples spiked at different amounts. The mean recovery and coefficient of variation (CV were 95.90% and 15.42%, respectively. The Mab-based ELISA achieved a great improvement in AVMs detection. Results proved this broad-selective ELISA would be useful for the multi-residue determination of AVMs in milk without purification process.

  3. 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...

  4. Development of a sandwich ELISA for the thrombin light chain identified by serum proteome analysis

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    Kazuyuki Sogawa

    2017-08-01

    Full Text Available We previously identified novel biomarker candidates in biliary tract cancer (BTC using serum proteome analysis. Among several candidates, we focused on thrombin light chain which is a 4204 Da peptide as the most promising biomarker for BTC. To move thrombin light chain toward potential diagnostic use, we developed an enzyme immunoassay that enables to measure serum thrombin light chain levels.Both one monoclonal antibody specific to the N-termini and one polyclonal antibody were used to develop a sandwich ELISA for thrombin light chain. The assay was evaluated by comparing the results with those obtained by the ClinProt™ system. Serum samples were obtained from 20 patients with BTC, 20 patients with BBTDs and 20 HVs using the ClinProt™ system and ELISA.The results of the established ELISA showed a positive correlation with the findings by ClinProt™ system (slope=0.3386, intercept=34.901, r2=0.9641. The performance of the ELISA was satisfactory in terms of recovery (97.9–102.5% and within-run (1.5–4.8% and between-day (1.9–6.7% reproducibility. Serum thrombin light chain levels were significantly greater in BTC (176.5±47.2 ng/mL than in BBTDs (128.6±17.4 ng/mL and HVs (127.6±16.0 ng/mL (p<0.001.The sandwich ELISA developed in this study will be useful for validation of the diagnostic significance of serum thrombin light chain levels in various cancers. Keywords: Thrombin light chain, Biliary tract cancer, Sandwich ELISA, Serum biomarker

  5. 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

    that specifically recognizes human apoM in plasma using commercially available reagents. Commercial apoM antibodies were screened for compatibility in a sandwich ELISA-based assay. One optimal pair of antibodies was chosen, and sample preparation, buffers, and incubation times were optimized to generate a simple...... and reproducible method. Validation and comparison to a previously described ELISA for apoM confirmed that the assay displays a high degree of sensitivity, specificity, and precision. Our results show that commercially available antibodies can be used to accurately measure human plasma apoM. This method can...

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

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    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

  7. 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.

  8. 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.

  9. Monoclonal antibody-based ELISA to quantify the major allergen of Cynodon dactylon (Bermuda grass) pollen, Cyn d 1.

    Science.gov (United States)

    Duffort, O; Calabozo, B; González, R; Carpizo, J A; Barber, D; Polo, F

    2004-12-01

    Pollen of Bermuda grass (Cynodon dactylon) is an important cause of pollinosis in many areas of the world. Most patients show sensitivity to the major allergen Cyn d 1, a glycoprotein composed of a number of isoforms with a molecular mass of 31-32 kDa. The aim of this work was to develop a monoclonal antibody (mAb)-based ELISA to quantify Cyn d 1, and to assess the correlation of the allergen content with the biological activity of C. dactylon pollen extracts. After fusion of myeloma cells with spleen cells from a BALB/c mouse immunized with C. dactylon pollen extract, Cyn d 1-specific mAbs secreting hybridomas were selected, and the antibodies characterized. One of them (4.4.1) was used as the capture antibody in an ELISA method for Cyn d 1 quantitation. An anti-Cyn d 1 rabbit serum was used as the second antibody. Cyn d 1 was purified by immunoaffinity chromatography with mAb 4.4.1, characterized, and used as the standard in the assay. The identity, purity and isoallergen composition of affinity-purified Cyn d 1 was confirmed by N-terminal amino acid sequencing, SDS-PAGE, Western blot and 2D electrophoresis. The Cyn d 1 ELISA is highly specific and sensitive, with a detection limit of 0.24 ng/ml and a linear range of 1.1-9.2 ng/ml. An excellent correlation was found when the content of Cyn d 1, measured in 16 different extracts, was compared with the allergenic activity of the same extracts determined by RAST inhibition. The results prove the usefulness of the Cyn d 1 ELISA for the standardization of C. dactylon-allergen products on the basis of major allergen content. 2004 S. Karger AG, Basel.

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

    Science.gov (United States)

    Thaitrong, Numrin; Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Karoonuthaisiri, Nitsara

    2013-01-01

    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.

  11. 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.

  12. Comparison of R5 and G12 Antibody-Based ELISA Used for the Determination of the Gluten Content in Official Food Samples

    Directory of Open Access Journals (Sweden)

    Rupert Hochegger

    2015-11-01

    Full Text Available Celiac Disease (CD is one of the most common food intolerances. It comes along with serious damage of the mucosa in the small intestine and is caused by the storage proteins—termed “gluten”—of wheat, rye, barley and possibly oats. Sensitive individuals need to stick to a strict gluten-free diet. The gluten level in food products labeled as “gluten-free”, must not exceed 20 mg/kg. It is obvious that effective test methods are needed to accurately determine the gluten concentration in foods. The determination of the presence of gluten in foodstuffs is mainly done by means of an immunochemical method called ELISA (enzyme-linked immunosorbent assay. To check the suitability of a G12 antibody-based gluten detection kit for its use in official control systems a number of routine samples were tested in parallel with two different test kits, as would be done in a routine lab. The determination of the gluten content was performed on samples entering the official laboratory including samples from official control plans, commercially available and private samples to request gluten-free labels. The results obtained with the G12 antibody ELISA assay were comparable to the official R5 method. A validation of the two different methods was not part of this study.

  13. Quantification of Pla or 3, a Platanus orientalis Allergen, Grown under Different Environmental Conditions, by Sandwich ELISA.

    Science.gov (United States)

    Sedghy, Farnaz; Sankian, Mojtaba; Moghadam, Maliheh; Varasteh, Abdol-Reza

    2016-10-01

    Platanus species are widely cultured around the world and considered an important cause of allergic reactions. In the present study, we developed a sandwich ELISA to quantify Pla or 3 allergen in P. orientalis pollen extracts grown near high-traffic roads and compared it to pollen extracts collected from rural areas as control. Pollen samples were collected from three polluted and two unpolluted sites in Mashhad, northeast Iran. Recombinant Pla or 3 was expressed and used for polyclonal antibody production in rabbit. A sandwich ELISA was developed and validated to quantify Pla or 3 levels in pollen extracts from the different sites. The coefficients of variation (CVs) for the intra- and inter- day assays were less than 5 and 18%, respectively. The working range of the standard curve was between 0.1 and 25 ng/ml, with the detection limit being 0.037 ng/ml. The recovery percentage was 88-106.4% at working concentrations from 0.31 to 26.5 ng/ml. Pla or 3 levels were significantly greater in pollens grown near high-traffic roads than in those grown in rural regions (p Pla or 3 in pollen extracts. Using this validated ELISA, we showed a substantial difference between the amounts of Pla or 3 in pollens grown in different environments. This finding should be considered in developing public policies to reduce traffic pollution, which leads to reduced allergic reactions in atopic subjects.

  14. Pistachio (Pistacia vera L.) Detection and Quantification Using a Murine Monoclonal Antibody-Based Direct Sandwich Enzyme-Linked Immunosorbent Assay.

    Science.gov (United States)

    Liu, Changqi; Chhabra, Guneet S; Sathe, Shridhar K

    2015-10-21

    A commercially available direct sandwich enzyme-linked immunosorbent assay (ELISA) (BioFront Technologies, Tallahassee, FL, USA) using murine anti-pistachio monoclonal antibodies (mAbs) as capture and detection antibodies was evaluated. The assay was sensitive (limit of detection = 0.09 ± 0.02 ppm full fat pistachio, linear detection range = 0.5-36 ppm, 50% maximum signal concentration = 7.9 ± 0.7 ppm), reproducible (intra- and inter-assay variability pistachio seeds subjected to autoclaving (121 °C, 15 psi, 15, 30 min), blanching (100 °C, 5, 10 min), frying (191 °C, 1 min), microwaving (500, 1000 W, 3 min), and dry roasting (140 °C, 30 min; 168 °C, 12 min). No cross-reactivity was observed in 156 food matrices, each tested at 100,000 ppm, suggesting the ELISA to be pistachio specific. The pistachio recovery ranges for spiked (10 ppm) and incurred (10-50000 ppm) food matrices were 93.1-125.6% and 35.7-112.2%, respectively. The assay did not register any false-positive or -negative results among the tested commercial and laboratory prepared samples.

  15. Sandwich enzyme-linked immunosorbent assay (ELISA) for measuring the concentration of, and detection of antibodies to, Aujeszky's disease virus.

    Science.gov (United States)

    Kardi, V; Szegletes, E; Perényi, T; Pergel, I; Smal, Z

    1990-01-01

    A double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed for measuring Aujeszky's disease virus (ADV) antigen concentration and an inhibition technique based on the former was developed for detection of antibodies to ADV. The results were checked by determining the cytopathic and serum neutralization titres. The correlation was satisfactory in both cases, with correlation coefficients above 0.8. When measuring ADV antigen concentration, the lower limit of detection was 10(3) TCID 50/0.2 ml. The sensitivity of ELISA in detecting antibodies to ADV was found to be superior to that of the serum neutralization test and, thus, enabled the testing of rabbit and guinea-pig sera.

  16. Detection of ciguatoxin in fish tissue using sandwich ELISA and neuroblastoma cell bioassay.

    Science.gov (United States)

    Empey Campora, Cara; Dierking, Jan; Tamaru, Clyde S; Hokama, Yoshitsugi; Vincent, Douglas

    2008-01-01

    The applicability of a new enzyme-linked immunoassay (ELISA) for detecting ciguatoxin (CTX) in fish tissue was evaluated by testing three fish species commonly implicated in ciguatera fish poisoning in Hawaii. A total of 164 individual almaco jack (Seriola rivoliana) and greater amberjack (S. dumerili) and a total of 175 individuals of the blue-spotted grouper (Cephalopholis argus) were caught at various locations in the Hawaiian Islands. Muscle tissue from each individual was assessed for the presence of CTX using two methods: a semi-quantitative ELISA that was recently developed for detecting picogram levels of CTX in fish extract and a neuroblastoma (NB) cell assay commonly used to screen for marine toxins in fish. Results of the tests were highly correlated, with the ELISA indicating the presence of CTX in 9.4% of all fish samples, and the NB assay indicating toxicity in 6.8% of the fish samples. We conclude that the ELISA produces reliable and accurate results that are consistent with those provided by the accepted NB assay and that the ELISA has potential for future applications in screening fish populations for CTX.

  17. 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.

  18. Laboratory safe detection of nucleocapsid protein of Rift Valley fever virus in human and animal specimens by a sandwich ELISA.

    Science.gov (United States)

    Jansen van Vuren, P; Paweska, J T

    2009-04-01

    A safe laboratory procedure, based on a sandwich ELISA (sAg-ELISA), was developed and evaluated for the detection of nucleocapsid protein (NP) of Rift Valley fever virus (RVFV) in specimens inactivated at 56 degrees C for 1h in the presence of 0.5% Tween-20 (v/v) before testing. Polyclonal capture and detection immune sera were generated respectively in sheep and rabbits immunized with recombinant NP antigen. The assay was highly repeatable and specific; it detected strains of RVFV from the entire distributional range of the disease, isolated over a period of 53 years; no cross-reactivity with genetically related African phleboviruses or other members of the family Bunyaviridae was observed. In specimens spiked with RVFV, including human and animal sera, homogenates of liver and spleen tissues of domestic ruminants, and Anopheles mosquito homogenates, the sAg-ELISA detection limit ranged from log(10)10(2.2) to 10(3.2) TCID(50)/reaction volume. The ELISA detected NP antigen in spiked bovine and sheep liver homogenates up to at least 8 days of incubation at 37 degrees C whereas infectious virus could not be detected at 48h incubation in these adverse conditions. Compared to virus isolation from sera from RVF patients and sheep infected experimentally, the ELISA had 67.7% and 70% sensitivity, and 97.97% and 100% specificity, respectively. The assay was 100% accurate when testing tissues of various organs from mice infected experimentally and buffalo foetuses infected naturally. The assay was able to detect NP antigen in infective culture supernatants 16-24h before cytopathic effects were observed microscopically and as early as 8h after inoculation with 10(5.8) TCID(50)/ml of RVFV. This ability renders the assay for rapid identification of the virus when its primary isolation is attempted in vitro. As a highly specific, safe and simple assay format, the sAg-ELISA represents a valuable diagnostic tool for use in less equipped laboratories in Africa, and for routine

  19. 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...

  20. Development of a Monoclonal Antibody-Based icELISA for the Detection of Ustiloxin B in Rice False Smut Balls and Rice Grains

    Directory of Open Access Journals (Sweden)

    Xiaoxiang Fu

    2015-08-01

    Full Text Available Rice false smut is an emerging and economically-important rice disease caused by infection by the fungal pathogen Villosiclava virens. Ustiloxin B is an antimitotic cyclopeptide mycotoxin isolated from the rice false smut balls that formed in the pathogen-infected rice spikelets. A monoclonal antibody (mAb designated as mAb 1B5A10 was generated with ustiloxin B—ovalbumin conjugate. A highly-sensitive and specific indirect competitive enzyme-linked immunosorbent assay (icELISA was then developed. The median inhibitory concentration (IC50 of the icELISA was 18.0 ng/mL for the detection of ustiloxin B; the limit of detection was 0.6 ng/mL, and the calibration range was from 2.5 to 107.4 ng/mL. The LOD/LOQ values of the developed ELISA used for the determination of ustiloxin B in rice false smut balls and rice grains were 12/50 μg/g and 30/125 ng/g, respectively. The mAb 1B5A10 cross-reacted with ustiloxin A at 13.9% relative to ustiloxin B. Average recoveries of ustiloxin B ranged from 91.3% to 105.1% for rice false smut balls at spiking levels of 0.2 to 3.2 mg/g and from 92.6% to 103.5% for rice grains at spiking levels of 100 to 5000 ng/g. Comparison of ustiloxin B content in rice false smut balls and rice grains detected by both icELISA and high performance liquid chromatography (HPLC demonstrated that the developed icELISA can be employed as an effective and accurate method for the detection of ustiloxin B in rice false smut balls, as well as rice food and feed samples.

  1. Construction, expression, purification and biotin labeling of a single recombinant multi-epitope antigen for double-antigen sandwich ELISA to detect hepatitis C virus antibody.

    Science.gov (United States)

    He, Jing; Xiu, Bingshui; Wang, Guohua; Chen, Kun; Feng, Xiaoyan; Song, Xiaoguo; Zhu, Cuixia; Yang, Xiqin; Bai, Guanzhong; Ling, Shigan; Zhang, Heqiu

    2011-08-01

    Based on B cell epitope predictions, a recombinant antigen with multiple epitopes from four Hepatitis C Virus fragments (C, NS3, NS4 and NS5) were engineered. The recombinant gene was then highly expressed in E. coli. The non-modified and C-terminal-modified recombinant proteins were used for coating and biotin labeling, respectively, to establish the double-antigen sandwich ELISA. Ten positive reference samples confirmed by the CHIRON RIBA HCV 3.0 SIA kit were detected positive, Forty one plasma samples were positive among samples from 441 volunteers, which indicated that the recombinant antigen could readily react well with plasma HCV antibody. As critical reagents of double-antigen sandwich ELISA, the recombinant multi-epitope antigen and the C-terminal-modified and biotin-conjugated antigen show good antigenicity. In this study, we provide a simple approach to produce multiple epitopes within one recombinant protein in order to avoid the costly expression of less-effective pools of multiple proteins, which is the conventional strategy of diagnostic antigen production for HCV antibody detection.

  2. Different conformational forms of serum carnosinase detected by a newly developed sandwich ELISA for the measurements of carnosinase concentrations

    NARCIS (Netherlands)

    Adelmann, Katja; Frey, Dirk; Riedl, Eva; Koeppel, Hannes; Pfister, Frederick; Peters, Verena; Schmitt, Claus P.; Sternik, Paula; Hofmann, Stephanie; Zentgraf, Hans Walter; Navis, Gerjan; van den Born, Jacob; Bakker, Stephan J. L.; Kraemer, Bernhard K.; Yard, Benito A.; Hauske, Sibylle J.

    Serum carnosinase (CN-1) measurements are at present mainly performed by assessing enzyme activity. This method is time-consuming, not well suited for large series of samples and can be discordant to measurements of CN-1 protein concentrations. To overcome these limitations, we developed sandwich

  3. 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.

  4. 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.

  5. Quantification of alpha-tubulin isotypes by sandwich ELISA with signal amplification through biotinyl-tyramide or immuno-PCR

    Czech Academy of Sciences Publication Activity Database

    Dráberová, Eduarda; Stegurová, Lucie; Sulimenko, Vadym; Hájková, Zuzana; Dráber, Petr; Dráber, Pavel

    2013-01-01

    Roč. 395, 1-2 (2013), s. 63-70 ISSN 0022-1759 R&D Projects: GA AV ČR KAN200520701; GA ČR GAP302/12/1673; GA ČR GPP302/11/P709; GA ČR GAP302/10/1759; GA ČR GA301/09/1826; GA MŠk(CZ) LD13015; GA MŠk LD12073 Institutional support: RVO:68378050 Keywords : alpha-tubulin isotypes * biotinyl-tyramide * ELISA * immuno-PCR * mast cells Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.005, year: 2013

  6. Streptavidin-biotin-based directional double Nanobody sandwich ELISA for clinical rapid and sensitive detection of influenza H5N1.

    Science.gov (United States)

    Zhu, Min; Gong, Xue; Hu, Yonghong; Ou, Weijun; Wan, Yakun

    2014-12-20

    Influenza H5N1 is one subtype of the influenza A virus which can infect human bodies and lead to death. Timely diagnosis before its breakout is vital to the human health. The current clinical biochemical diagnosis for influenza virus are still flawed, and the diagnostic kits of H5N1 are mainly based on traditional monoclonal antibodies that hardly meet the requirements for clinical applications. Nanobody is a promising tool for diagnostics and treatment due to its smallest size, high specificity and stability. In this study, a novel Nanobody-based bioassay was developed for rapid, low-cost and sensitive detection of the influenza H5N1 virus. Nanobodies specific to H5N1 virus were selected from a VHH library by phage display technology. In this system, the biotinylated Nanobody was directionally captured by streptavidin coated on ELISA plate, which can specifically capture the H5N1 virus. Another Nanobody conjugated with HRP was used as a detector. A novel directional enzyme-linked immunosorbent assay for H5N1 using specific Nanobodies was established and compared to the conventional undirected ELISA assay. We have successfully constructed a high quality phage display Nanobody library and isolated two Nanobodies against H5N1 with high affinity and specificity. These two Nanobodies were further used to prepare the biosensor detection system. This streptavidin-biotin-based directional double Nanobodies sandwich ELISA for H5N1 detection showed superiority over the commonly undirectional ELISA protocol. The linear range of detection for standards in this immunoassay was approximately 50-1000 ng/mL and the detection limit was 14.1 ng/mL. The average recoveries of H5N1 virus from human serum samples were in the range from 94.58% to 114.51%, with a coefficient of variation less than 6.5%. Collectively, these results demonstrated that the proposed detection system is an alternative diagnostic tool that enables a rapid, inexpensive, sensitive and specific detection of the

  7. A simple sandwich ELISA (WELYSSA) for the detection of lyssavirus nucleocapsid in rabies suspected specimens using mouse monoclonal antibodies.

    Science.gov (United States)

    Xu, Gelin; Weber, Patrick; Hu, Qiaoling; Xue, Honggang; Audry, Laurent; Li, Chengping; Wu, Jie; Bourhy, Herve

    2007-10-01

    Monoclonal antibody (MAb)-based capture enzyme-linked immunosorbent assays (ELISA) were developed for the diagnosis of rabies-suspect specimens. A combination of four mouse monoclonal antibodies directed against the rabies virus nucleocapsid was selected and used for the detection. The test was optimized and standardized so that maximum concordance could be maintained with the standard procedures of rabies diagnosis recommended by the WHO expert committee. Using prototype viruses from the different genotypes of lyssavirus and from various geographic origins and phylogenetic lineages, this paper presents a reliable, rapid and transferable diagnostic method, named WELYSSA that readily permits the detection of lyssaviruses belonging to the 7 genotypes of lyssavirus circulating in Europe, Africa, Asia and Oceania. The threshold of detection of lyssavirus nucleocapsids is low (0.8 ng/ml). With a panel of 1030 specimens received for rabies diagnostic testing, this test was found to be highly specific (0.999) and sensitive (0.970) when compared to other recommended rabies diagnostic methods.

  8. 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Establishment of sandwich ELISA for soluble alpha-Klotho measurement: Age-dependent change of soluble alpha-Klotho levels in healthy subjects.

    Science.gov (United States)

    Yamazaki, Yuji; Imura, Akihiro; Urakawa, Itaru; Shimada, Takashi; Murakami, Junko; Aono, Yukiko; Hasegawa, Hisashi; Yamashita, Takeyoshi; Nakatani, Kimihiko; Saito, Yoshihiko; Okamoto, Nozomi; Kurumatani, Norio; Namba, Noriyuki; Kitaoka, Taichi; Ozono, Keiichi; Sakai, Tomoyuki; Hataya, Hiroshi; Ichikawa, Shoji; Imel, Erik A; Econs, Michael J; Nabeshima, Yo-Ichi

    2010-07-30

    Alpha-Klotho (alphaKl) regulates mineral metabolism such as calcium ion (Ca(2+)) and inorganic phosphate (Pi) in circulation. Defects in mice result in clinical features resembling disorders found in human aging. Although the importance of transmembrane-type alphaKl has been demonstrated, less is known regarding the physiological importance of soluble-type alphaKl (salphaKl) in circulation. The aims of this study were: (1) to establish a sandwich ELISA system enabling detection of circulating serum salphaKl, and (2) to determine reference values for salphaKl serum levels and relationship to indices of renal function, mineral metabolism, age and sex in healthy subjects. We successively developed an ELISA to measure serum salphaKl in healthy volunteers (n=142, males 66) of ages (61.1+/-18.5year). The levels (mean+/-SD) in these healthy control adults were as follows: total calcium (Ca; 9.46+/-0.41mg/dL), Pi (3.63+/-0.51mg/dL), blood urea nitrogen (BUN; 15.7+/-4.3mg/dL), creatinine (Cre; 0.69+/-0.14mg/dL), 1,25 dihydroxyvitamin D (1,25(OH)(2)D; 54.8+/-17.7pg/mL), intact parathyroid hormone (iPTH; 49.2+/-20.6pg/mL), calcitonin (26.0+/-12.3pg/mL) and intact fibroblast growth factor (FGF23; 43.8+/-17.6pg/mL). Serum levels of salphaKl ranged from 239 to 1266pg/mL (mean+/-SD; 562+/-146pg/mL) in normal adults. Although salphaKl levels were not modified by gender or indices of mineral metabolism, salphaKl levels were inversely related to Cre and age. However, salphaKl levels in normal children (n=39, males 23, mean+/-SD; 7.1+/-4.8years) were significantly higher (mean+/-SD; 952+/-282pg/mL) than those in adults (mean+/-SD; 562+/-146, Plevel was notably lower than those of age-matched controls. We established a detection system to measure human serum salphaKl for the first time. Age, Ca and Pi seem to influence serum salphaKl levels in a normal population. This detection system should be an excellent tool for investigating salphaKl functions in mineral metabolism. Copyright

  10. 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.

  11. 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. PMID:26930597

  12. 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

  13. A monoclonal-monoclonal antibody based capture elisa for abrin

    Science.gov (United States)

    Abrin, one of the most highly potent toxins in the world, is derived from the plant, Abrus precatorius. Because of its high toxicity, it poses potential bioterror risks. Therefore, a need exists for new reagents and technologies that would be able to rapidly detect abrin contamination as well as lea...

  14. A sensitive monoclonal antibody-based enzyme-linked immunosorbent assay for chlorpyrifos residue determination in Chinese agricultural smaples

    Science.gov (United States)

    A monoclonal antibody-based competitive antibody-coated enzyme-linked immunosorbent assay (ELISA) was developed and optimized for determining chlorpyrifos residue in agricultural products. The IC50 and IC10 of this ELISA were 3.3 ng/mL and 0.1 ng/mL respectively. The average recoveries recovery rate...

  15. Elisa Miller | NREL

    Science.gov (United States)

    Elisa Miller Photo of Elisa Miller Elisa Link-Miller Researcher III-Chemistry Elisa.Miller@nrel.gov | 303-384-6777 Dr. Elisa Miller-Link studies the surface of semiconductors that are applicable for , and other nanocrystalline films. Elisa came to NREL in 2013 as an NREL Director's Fellowship recipient

  16. 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.

  17. SIGNS The sandwich sign

    African Journals Online (AJOL)

    The sandwich sign is demonstrated on cross-sectional imaging, commonly on CT or ultrasound. It refers to homogeneous soft- tissue masses representing mesenteric lymphadenopathy as the two halves of a sandwich bun, encasing the mesenteric fat and tubular mesenteric vessels that constitute the 'sandwich filling' (Figs ...

  18. Purification of a polyclonal antibody against CD147 for ELISA using antigen-immunoaffinity chromatography

    Science.gov (United States)

    Liu, Shuangshuang; Li, Shasha; Zhang, Yang; Wang, Ye; Zhu, Yumeng; Wang, Bin; Chen, Zhi-Nan

    2017-01-01

    The immunoglobulin superfamily member CD147 is a widely expressed glycoprotein that occurs in both a membrane-spanning and soluble form. Sandwich ELISA is a powerful tool for analyzing soluble antigens. The aim of the present study was to obtain a highly specific polyclonal antibody against human CD147 that can be used for sandwich ELISA analysis. Expression of recombinant CD147 by a eukaryotic expression system was used to immunize rabbits to obtain antiserum. A highly specific polyclonal antibody that was able to detect soluble CD147 in sandwich ELISA was obtained by antigen-immunoaffinity chromatography purification. The purity of rabbit anti-CD147 polyclonal antibodies was ~99%, and ELISA analysis was able to determine the titer of the rabbit anti-CD147 polyclonal antibodies at 1:512,000. The lowest concentration of the standard CD147 antigen that the sandwich ELISA was able to detect was 31.25 pg/ml. The sandwich ELISA system was composed of anti-hepatoma HAb18 monoclonal antibodies and purified rabbit anti-CD147 polyclonal antibodies. The present study demonstrated that antigen-immunoaffinity chromatography may be a good technique for the purification of polyclonal antibodies, which may be used to detect antigen in sandwich ELISAs. PMID:28487989

  19. Monoclonal antibody-based serological methods for detection of Cucumber green mottle mosaic virus

    Directory of Open Access Journals (Sweden)

    Qian Yajuan

    2011-05-01

    Full Text Available Abstract Background Cucumber green mottle mosaic virus (CGMMV, a member of the genus Tobamovirus, can be transmitted by seeds and infects many cucurbit species, causing serious yield losses in cucumber and watermelon plants. In this paper, five serological methods including antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA, triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA, Dot-immunobinding assay (DBIA, direct tissue blot immunoassay (DTBIA and immunocapture reverse transcriptase polymerase chain reaction (IC-RT-PCR were described for detection and diagnosis of CGMMV. Results Using the purified CGMMV particles as immunogens, six murine monoclonal antibodies (MAbs were produced. Five serological methods were established using the MAb 4H1 and detection sensitivity was compared using purified preparations and infected-plant tissue extracts. The detection sensitivity of ACP-ELISA was 0.16 ng of purified CGMMV, whereas TAS-ELISA was more sensitive than ACP-ELISA with a minimum detection of 0.04 ng of purified CGMMV. The sensitivities of TAS-ELISA and DBIA were similar for detecting CGMMV in infected-plant tissue extracts, and were four times higher than ACP-ELISA. The IC-RT-PCR was the most sensitive method, which could detect as little as 0.1 pg of purified virus. The detection sensitivity of IC-RT-PCR for CGMMV-infected plant tissues was about 400 times higher than that of TAS-ELISA and DBIA. Conclusions The established ACP-ELISA, TAS-ELISA, DBIA and DTBIA are suitable for routine CGMMV detection of large-scale samples in the field survey, while IC-RT-PCR is more sensitive and suitable for acquiring information about the viral genome.

  20. A monoclonal antibody-based ELISA for the hedgehog inhibitors cyclopamine and cyclopamine derivatives

    Science.gov (United States)

    In the late 1960’s cyclopamine was isolated from the plant Veratrum californicum and identified as the teratogen responsible for craniofacial birth defects including cyclops in the offspring of sheep grazing on mountain ranges in the western United States. More recently, cyclopamine was found to inh...

  1. A monoclonal antibody based capture ELISA for botulinum neurotoxin serotype B: toxin detection in food

    Science.gov (United States)

    Botulism is a serious foodborne neuroparalyic 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 repo...

  2. A monoclonal antibody-based ELISA for differential diagnosis of 2009 pandemic H1N1

    Science.gov (United States)

    The swine-origin 2009 pandemic H1N1 virus (pdmH1N1) is genetically related to North American swine H1 influenza viruses and unrelated to human seasonal H1 viruses. Currently, specific diagnosis of pdmH1N1 relies on RT-PCR. In order to develop an assay that does not rely in amplification of the viral...

  3. A murine monoclonal antibody based enzyme-linked immunosorbent assay for almond (Prunus dulcis L.) detection.

    Science.gov (United States)

    Su, Mengna; Venkatachalam, Mahesh; Liu, Changqi; Zhang, Ying; Roux, Kenneth H; Sathe, Shridhar K

    2013-11-13

    A sandwich enzyme-linked immunosorbent assay (ELISA) using anti-almond soluble protein rabbit polyclonal antibodies as capture antibodies and murine monoclonal antibody 4C10 as the detection antibodies was developed. The assay is specific and sensitive (3-200 ng almond protein/mL) for almond detection. The standardized assay is accurate (assay variability assay did not register any cross-reactivity with the tested food matrices, suggesting the assay to be almond amandin specific. The assay could detect the presence of declared almond in the tested matched commercial samples. Further, the assay reliably detected the presence of almonds in the laboratory prepared food samples spiked with almond flour.

  4. Monoclonal antibody-based dipstick assay: a reliable field applicable technique for diagnosis of Schistosoma mansoni infection using human serum and urine samples.

    Science.gov (United States)

    Demerdash, Zeinab; Mohamed, Salwa; Hendawy, Mohamed; Rabia, Ibrahim; Attia, Mohy; Shaker, Zeinab; Diab, Tarek M

    2013-02-01

    A field applicable diagnostic technique, the dipstick assay, was evaluated for its sensitivity and specificity in diagnosing human Schistosoma mansoni infection. A monoclonal antibody (mAb) against S. mansoni adult worm tegumental antigen (AWTA) was employed in dipstick and sandwich ELISA for detection of circulating schistosome antigen (CSA) in both serum and urine samples. Based on clinical and parasitological examinations, 60 S. mansoni-infected patients, 30 patients infected with parasites other than schistosomiasis, and 30 uninfected healthy individuals were selected. The sensitivity and specificity of dipstick assay in urine samples were 86.7% and 90.0%, respectively, compared to 90.0% sensitivity and 91.7% specificity of sandwich ELISA. In serum samples, the sensitivity and specificity were 88.3% and 91.7% for dipstick assay vs. 91.7% and 95.0% for sandwich ELISA, respectively. The diagnostic efficacy of dipstick assay in urine and serum samples was 88.3% and 90.0%, while it was 90.8% and 93.3% for sandwich ELISA, respectively. The diagnostic indices of dipstick assay and ELISA either in serum or in urine were statistically comparable (P>0.05). In conclusion, the dipstick assay offers an alternative simple, rapid, non-invasive technique in detecting CSA or complement to stool examinations especially in field studies.

  5. Predicting safe sandwich production

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... 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...

  6. Salads, Sandwiches and Desserts.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on salads, sandwiches, and desserts is designed to provide Marine food service personnel with a general background in the proper techniques for the preparation of these items. Introductory materials include specific information for MCI students and a…

  7. 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

    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...... 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...

  8. Antibody-Based Immunotoxins for the Treatment of Cancer

    OpenAIRE

    Nurit Becker; Itai Benhar

    2012-01-01

    Antibody-based immunotoxins comprise an important group in targeted cancer therapeutics. These chimeric proteins are a form of biological guided missiles that combine a targeting moiety with a potent effector molecule. The targeting moiety is mostly a monoclonal antibody (MAb) or a recombinant antibody-based fragment that confers target specificity to the immunotoxin. The effector domain is a potent protein toxin of bacterial or plant origin, which, following binding to the target cells, unde...

  9. Radioimmunoassays and 2-site immunoradiometric 'sandwich' assays: basic principles

    Energy Technology Data Exchange (ETDEWEB)

    Rodbard, D

    1988-10-01

    The 'sandwich' or noncompetitive reagent-excess, 2-site immunoradiometric assay (2-site IRMA), ELISA, USERIA, and related techniques, have several advantages compared with the traditional or competitive radioimmunoassays. IRMAs can provide improved sensitivity and specificity. However, IRMAs present some practical problems with nonspecific binding, increased consumption of antibody, biphasic dose response curve, (high dose hook effect), and may require special techniques for dose response curve analysis. We anticipate considerable growth in the popularity and importance of 2-site IRMA.

  10. Radioimmunoassays and 2-site immunoradiometric "sandwich" assays: basic principles.

    Science.gov (United States)

    Rodbard, D

    1988-10-01

    The "sandwich" or noncompetitive reagent-excess, 2-site immunoradiometric assay (2-site IRMA), ELISA, USERIA, and related techniques, have several advantages compared with the traditional or competitive radioimmunoassays. IRMAs can provide improved sensitivity and specificity. However, IRMAs present some practical problems with nonspecific binding, increased consumption of antibody, biphasic dose response curve, (high dose hook effect), and may require special techniques for dose response curve analysis. We anticipate considerable growth in the popularity and importance of 2-site IRMA.

  11. 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

  12. Immunodiagnosis of fascioliasis using sandwich enzyme-linked immunosorbent assay for detection of Fasciola gigantica paramyosin antigen

    Science.gov (United States)

    Abou-Elhakam, Hany Mohamed Adel; Bauomy, Ibraheem Rabia; El Deeb, Somaya Osman; El Amir, Azza Mohamed

    2013-01-01

    Background: Many immunological techniques have been developed over years using the different Fasciola antigens for diagnosis of parasitic infection and to replace the parasitological techniques, which are time consuming and usually lack sensitivity and reproducibility. Materials and Methods: In this study, Fasciola gigantica paramyosin (Pmy) antigen was early detected in cattle sera using sandwich enzyme-linked immunosorbent assay (ELISA), to evaluate the Pmy antigen performance in diagnosis. This work was conducted on 135 cattle blood samples, which were classified according to parasitological investigation into, healthy control (30), fascioliasis (75), and other parasites (30) groups. Results: The sensitivity of Sandwich ELISA was 97.33%, and the specificity was 95%, in comparison with parasitological examination, which recorded 66.66% sensitivity and 100% specificity, respectively. Conclusions: It was clear that the native F. gigantica Pmy is considered as a powerful antigen in early immunodiagnosis of fascioliasis, using a highly sensitive and specific sandwich ELISA technique. PMID:23961441

  13. 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.

  14. Novel Antibody-Based Proteins for Cancer Immunotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Fuenmayor, Jaheli; Montaño, Ramon F., E-mail: jfuenmay@ivic.gob.ve [Laboratorio de Patología Celular y Molecular, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas. Caracas, 1020-A (Venezuela, Bolivarian Republic of)

    2011-08-19

    The relative success of monoclonal antibodies in cancer immunotherapy and the vast manipulation potential of recombinant antibody technology have encouraged the development of novel antibody-based antitumor proteins. Many insightful reagents have been produced, mainly guided by studies on the mechanisms of action associated with complete and durable remissions, results from experimental animal models, and our current knowledge of the human immune system. Strikingly, only a small percent of these new reagents has demonstrated clinical value. Tumor burden, immune evasion, physiological resemblance, and cell plasticity are among the challenges that cancer therapy faces, and a number of antibody-based proteins are already available to deal with many of them. Some of these novel reagents have been shown to specifically increase apoptosis/cell death of tumor cells, recruit and activate immune effectors, and reveal synergistic effects not previously envisioned. In this review, we look into different approaches that have been followed during the past few years to produce these biologics and analyze their relative success, mainly in terms of their clinical performance. The use of antibody-based antitumor proteins, in combination with standard or novel therapies, is showing significant improvements in objective responses, suggesting that these reagents will become important components of the antineoplastic protocols of the future.

  15. Development of a monoclonal antibody-based ELISA for the hedgehog inhibitors cyclopamine and cyclopamine-KAAD

    Science.gov (United States)

    Cyclopamine was isolated from Veratrum californicum and identified as the teratogen responsible for severe craniofacial birth defects including cyclops in the offspring of sheep grazing on mountain ranges in central Idaho. More recently, cyclopamine was found to inhibit the hedgehog (Hh) signaling ...

  16. 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

    2013-01-01

    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. PMID:24124274

  17. Detection of polyaromatic compounds using antibody-based fiberoptics fluoroimmunosensors

    International Nuclear Information System (INIS)

    Vo-Dinh, T.; Tromberg, B.J.; Griffin, G.D.; Ambrose, K.R.; Sepaniak, M.J.; Alarie, J.P.

    1987-01-01

    In this work we have investigated the performance of an antibody-based fiberoptics sensor for the detection of the carcinogen benzo(a)pyrene and its DNA-adduct product BP-tetrol. The excellent sensitivity of this device - femtomole limits of detection for BP - illustrates that it has considerable potential to perform analyses of chemical and biological samples at trace levels in complex matrices. The results indicate that fiberoptics-based fluoroimmunosensors can be useful in a wide spectrum of biochemical and clinical analyses. 17 refs., 4 figs., 1 tab

  18. Detection of polyaromatic compounds using antibody-based fiberoptics fluoroimmunosensors

    Energy Technology Data Exchange (ETDEWEB)

    Vo-Dinh, T.; Tromberg, B.J.; Griffin, G.D.; Ambrose, K.R.; Sepaniak, M.J.; Alarie, J.P.

    1987-01-01

    In this work we have investigated the performance of an antibody-based fiberoptics sensor for the detection of the carcinogen benzo(a)pyrene and its DNA-adduct product BP-tetrol. The excellent sensitivity of this device - femtomole limits of detection for BP - illustrates that it has considerable potential to perform analyses of chemical and biological samples at trace levels in complex matrices. The results indicate that fiberoptics-based fluoroimmunosensors can be useful in a wide spectrum of biochemical and clinical analyses. 17 refs., 4 figs., 1 tab.

  19. Antibody-Based Immunotoxins for the Treatment of Cancer

    Directory of Open Access Journals (Sweden)

    Nurit Becker

    2012-05-01

    Full Text Available Antibody-based immunotoxins comprise an important group in targeted cancer therapeutics. These chimeric proteins are a form of biological guided missiles that combine a targeting moiety with a potent effector molecule. The targeting moiety is mostly a monoclonal antibody (MAb or a recombinant antibody-based fragment that confers target specificity to the immunotoxin. The effector domain is a potent protein toxin of bacterial or plant origin, which, following binding to the target cells, undergoes internalization and causes cell death. Over time and following research progression, immunotoxins become better fitted to their purpose, losing immunogenic fragments and non-specific targeting moieties. Many immunotoxins have gone through clinical evaluation. Some of these have been shown to be active and work is progressing with them in the form of further clinical trials. Others, mostly developed in the previous century, failed to generate a response in patients, or even caused undesired side effects. This article reviews the antibody and protein-toxin based immunotoxins that were clinically evaluated up to the present day.

  20. 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

  1. 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.

  2. 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

  3. Novel sensitive monoclonal antibody based competitive enzyme-linked immunosorbent assay for the detection of raw and processed bovine beta-casein.

    Science.gov (United States)

    Castillo, Daniela S; Cassola, Alejandro

    2017-01-01

    Cow milk protein allergy (CMPA) is the most common childhood food allergy, which can sometimes persist or can newly develop in adulthood with severe symptoms. CMPA's treatment is complete dietary avoidance of milk proteins. To achieve this task, patients have to be aware of milk proteins found as "hidden allergens" in food commodities. In regard to milk proteins, it has been reported that allergenicity of caseins remains unaffected upon heat treatment. For these reasons, we aimed to obtain monoclonal antibodies (mAbs) against native and denatured β-casein, one of the most abundant and antigenic caseins, in order to develop an indirect competitive ELISA (icELISA) to detect and quantify traces of this milk allergen in raw and processed foodstuffs. We developed two specific hybridoma clones, 1H3 and 6A12, which recognized β-casein in its denatured and native conformations by indirect ELISA (iELISA). Cross-reaction analysis by Western blot and iELISA indicated that these mAbs specifically recognized β-casein from bovine and goat milk extracts, while they did not cross-react with proteins present in other food matrixes. These highly specific mAbs enabled the development of sensitive, reliable and reproducible icELISAs to detect and quantify this milk protein allergen in food commodities. The extraction of β-casein from foodstuff was efficiently carried out at 60°C for 15 minutes, using an extraction buffer containing 1% SDS. The present study establishes a valid 1H3 based-icELISA, which allows the detection and quantification -0.29 ppm and 0.80 ppm, respectively- of small amounts of β-casein in raw and processed foods. Furthermore, we were able to detect milk contamination in incurred food samples with the same sensitivity as a commercial sandwich ELISA thus showing that this icELISA constitutes a reliable analytical method for control strategies in food industry and allergy prevention.

  4. The Platelia Aspergillus ELISA in diagnosis of invasive pulmonary aspergilosis (IPA).

    Science.gov (United States)

    Siemann, M; Koch-Dörfler, M

    2001-01-01

    The sensitivity of a sandwich enzyme-linked immunosorbent assay (ELISA) for detecting Aspergillus galactomannan was evaluated with 66 serum samples and 113 specimens of the respiratory tract obtained from 52 patients with pulmonary diseases. The patients were divided into five groups: proven invasive pulmonary aspergillosis (IPA) (five patients), probable IPA (seven patients), Aspergillus colonization (eight patients) or unlikely Aspergillus infection (27 patients). Another five patients with doubtful diagnostic test results are discussed in detail. The results of the Platelia Aspergillus ELISA (Sanofi Pasteur, Freiburg, Germany) in testing specimens of the respiratory tract were 90% sensitivity in proven (serum 38%), 60% in probable (serum 37%) and 71% in Aspergillus colonization (serum 0%). Furthermore, 85% of the Aspergillus spp. from positive cultures of specimens of the respiratory tract were also detected in the ELISA. A total of 57% of the culture negative specimens of patients with a least one positive culture or proven aspergillosis in a series of specimens were positive in the ELISA.

  5. Follow-up of neurocysticercosis patients after treatment using an antigen detection ELISA

    Directory of Open Access Journals (Sweden)

    Nguekam

    2003-03-01

    Full Text Available Seven patients with active neurocysticercosis (NCC received an eight days treatment with albendazole and were followed up using computed tomography (CT-scan and a monoclonal antibody based ELISA for the detection of circulating antigen (Ag-ELISA. Only three patients were cured as was shown by CT-scan and by the disappearance of circulating antigens one month after treatment. After a second course of albendazole therapy, two other patients became seronegative. CT-scan showed the disappearance of viable cysts in all persons who became seronegative whereas patients who were not cured remained seropositive. These preliminary results show that this Ag-ELISA is a promising technique for monitoring the success of treatment of NCC patients because of the excellent correlation between the presence of circulating antigens and of viable brain cysts.

  6. Mobile phone based ELISA (MELISA).

    Science.gov (United States)

    Zhdanov, Arsenii; Keefe, Jordan; Franco-Waite, Luis; Konnaiyan, Karthik Raj; Pyayt, Anna

    2018-04-30

    Enzyme-linked immunosorbent assay (ELISA) is one of the most important technologies for biochemical analysis critical for diagnosis and monitoring of many diseases. Traditional systems for ELISA incubation and reading are expensive and bulky, thus cannot be used at point-of-care or in the field. Here, we propose and demonstrate a new miniature mobile phone based system for ELISA (MELISA). This system can be used to complete all steps of the assay, including incubation and reading. It weighs just 1 pound, can be fabricated at low cost, portable, and can transfer test results via mobile phone. We successfully demonstrated how MELISA can be calibrated for accurate measurements of progesterone and demonstrated successful measurements with the calibrated system. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Antibody-Based Strategies to Prevent and Treat Influenza

    Directory of Open Access Journals (Sweden)

    Ram eSasisekharan

    2015-07-01

    Full Text Available Passive immunization using antibodies has been suggested to offer several benefits in comparison to other antiviral treatment options. The potential for seasonal protection arising from a single injection of antibodies is appealing and has been pursued for a number of infectious agents. However, until recently, antibody-based strategies to combat infectious agents has been hampered due to the fact that typical antibodies have been found to be strain-specific, with the virus evolving resistance in many cases. The discovery of broadly neutralizing antibodies (bNAbs in, for example, influenza, dengue virus, and HIV, which bind to multiple, structurally-diverse strains has provided renewed interest in this area. This review will focus on new technologies that enable the discovery of bNAbs, the challenges and opportunities of immunotherapies as an important addition to existing antiviral therapy, and the role of antibody discovery in informing rational vaccine discovery – with agents targeting influenza specifically addressed. Multiple agents have entered the clinic and raise the possibility that a single antibody or small combination of antibodies can effectively neutralize a wide variety of strains. However, challenges remain - including combating escape variants, pharmacodynamics of antibody distribution, and development of efficacy biomarkers beyond virologic endpoints.

  8. Multiplexed salivary protein profiling for patients with respiratory diseases using fiber-optic bundles and fluorescent antibody-based microarrays.

    Science.gov (United States)

    Nie, Shuai; Benito-Peña, Elena; Zhang, Huaibin; Wu, Yue; Walt, David R

    2013-10-01

    Over the past 40 years, the incidence and prevalence of respiratory diseases have increased significantly throughout the world, damaging economic productivity and challenging health care systems. Current diagnoses of different respiratory diseases generally involve invasive sampling methods such as induced sputum or bronchoalveolar lavage that are uncomfortable, or even painful, for the patient. In this paper, we present a platform incorporating fiber-optic bundles and antibody-based microarrays to perform multiplexed protein profiling of a panel of six salivary biomarkers for asthma and cystic fibrosis (CF) diagnosis. The platform utilizes an optical fiber bundle containing approximately 50,000 individual 4.5 μm diameter fibers that are chemically etched to create microwells in which modified microspheres decorated with monoclonal capture antibodies can be deposited. On the basis of a sandwich immunoassay format, the array quantifies human vascular endothelial growth factor (VEGF), interferon gamma-induced protein 10 (IP-10), interleukin-8 (IL-8), epidermal growth factor (EGF), matrix metalloproteinase 9 (MMP-9), and interleukin-1 beta (IL-1β) salivary biomarkers in the subpicomolar range. Saliva supernatants collected from 291 individuals (164 asthmatics, 71 CF patients, and 56 healthy controls (HC)) were analyzed on the platform to profile each group of patients using this six-analyte suite. It was found that four of the six proteins were observed to be significantly elevated (p < 0.01) in asthma and CF patients compared with HC. These results demonstrate the potential to use the multiplexed protein array platform for respiratory disease diagnosis.

  9. ELISA

    Science.gov (United States)

    ... care provider about the meaning of your specific test results. What Abnormal Results ... and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than ...

  10. A novel Antibody based approach to Cancer Treatment

    Directory of Open Access Journals (Sweden)

    Yoshikazu Kurosawa

    2010-01-01

    Full Text Available Cancer is one of the leading causes of death among the human race. No valid modalities of treatment other than surgical treatment have been established for this disease. We aimed to identify and to characterize cancer using large number of human monoclonal antibodies (mAbs which are specific against their surface for new molecular targeted immunotherapy. In order to find proper targets for therapeutic antibodies against cancers we developed a screening strategy. We used a huge phage library of human antibodies. At the first step we comprehensively isolated many monoclonal antibodies (mAbs that specifically bound to surface of cancer cells. Development of ICOS (Isolation of antigen/antibody complexes through organic solvent method allowed us to succeed in isolation of a huge number of mAbs with various characteristics (Y Akahori et al. 2009. At the next step we selected clones that showed tumor-specific staining patterns in immunohistochemical (IHC analysis by using many fresh cancer tissues reseted. Many surgeons took part in this project. Finally the antigens recognized by these clones were identified by immunoprecipitation (IP followed by analysis with mass (MS spectrometry (G Kurosawa et al. 2009. We have succeeded in identification of 29 tumor-associated antigens (TAAs and in isolation of 441 human mAbs that specifically bound to one of the 29 TAAs (G Kurosawa et al. 2008. In these screenings of the library, rounds of the selection process, mixing of cells and phage particles centrifugation growth of phages, were repeated three to four times in each screening. Therefore, numbers of phages of the clones whose antigens were abundantly present on the cell surface increased during the screenings. Recently we developed a new method for isolation of clones whose antigens were less abundantly present on the cell surface. Hence, we would like to talk on these methodology and discuss regarding this “A novel antibody based approach to Cancer

  11. ELISA-BASE: an integrated bioinformatics tool for analyzing and tracking ELISA microarray data

    OpenAIRE

    White, Amanda M.; Collett, James R.; Seurynck-Servoss, Shannon L.; Daly, Don S.; Zangar, Richard C.

    2009-01-01

    Summary:ELISA-BASE is an open source database for capturing, organizing and analyzing enzyme-linked immunosorbent assay (ELISA) microarray data. ELISA-BASE is an extension of the BioArray Software Environment (BASE) database system.

  12. Development of sandwich enzyme-linked immunosorbent assay systems for plasma β-galactoside α2,6-sialyltransferase, a possible hepatic disease biomarker

    International Nuclear Information System (INIS)

    Futakawa, Satoshi; Kitazume, Shinobu; Oka, Ritsuko; Ogawa, Kazuko; Hagiwara, Yoshiaki; Kinoshita, Akinori; Miyashita, Kazuya; Hashimoto, Yasuhiro

    2009-01-01

    Previous reports, including our work, have shown that plasma β-galactoside α2,6-sialyltransferase (ST6Gal I) activity is significantly increased in particular hepatopathological situations, suggesting that it may represent a sensitive biomarker for diagnosing hepatic diseases. So far, activity of ST6Gal I have been measured by using radioactive tracer method in place of measuring amount of ST6Gal I. However, this method is tangled and cannot exclude other sialyltransferase activities. Thus, simple and specific methods for measuring plasma ST6Gal I had been unavailable. Here, we developed two kinds of sandwich enzyme-linked immunosorbent assay (ELISA) systems that specifically detect the soluble cleaved form of ST6Gal I in plasma. In one sandwich ELISA, we detected rat specific sequence, EFQMPK, which is N-terminus of soluble ST6Gal I. In the other sandwich ELISA, we detected internal common sequence among rat, mouse and human ST6Gal I in plasma (M2 ELISA). Using the M2 ELISA, we observed that elevation of plasma ST6Gal I was much faster than elevation of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a carbon tetrachloride (CCl 4 )-induced mouse liver injury model. Our data suggest that these ELISA systems are very useful tools for measuring plasma ST6Gal I, which represents a potential biomarker for diagnosing hepatic diseases

  13. Development of sandwich enzyme-linked immunosorbent assay systems for plasma {beta}-galactoside {alpha}2,6-sialyltransferase, a possible hepatic disease biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Futakawa, Satoshi [Department of Biochemistry, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima-shi, Fukushima 960-1295 (Japan); Kitazume, Shinobu [Disease Glycomics Laboratory, Institute of Physical and Chemical Research, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi-shi, Saitama 560-0082 (Japan); Oka, Ritsuko [CREST, Japan Science and Technology Agency, Kawaguchi-shi, Saitama 560-0082 (Japan); Glyco-chain Functions Laboratory, Institute of Physical and Chemical Research, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Ogawa, Kazuko [Disease Glycomics Laboratory, Institute of Physical and Chemical Research, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi-shi, Saitama 560-0082 (Japan); Hagiwara, Yoshiaki; Kinoshita, Akinori; Miyashita, Kazuya [Department of Biological Sciences, Immuno-Biological Laboratories Co. Ltd., 1091-1 Naka, Fujioka-shi, Gunma 375-0005 (Japan); Hashimoto, Yasuhiro [Department of Biochemistry, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima-shi, Fukushima 960-1295 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi-shi, Saitama 560-0082 (Japan)], E-mail: yasuc@fmu.ac.jp

    2009-01-05

    Previous reports, including our work, have shown that plasma {beta}-galactoside {alpha}2,6-sialyltransferase (ST6Gal I) activity is significantly increased in particular hepatopathological situations, suggesting that it may represent a sensitive biomarker for diagnosing hepatic diseases. So far, activity of ST6Gal I have been measured by using radioactive tracer method in place of measuring amount of ST6Gal I. However, this method is tangled and cannot exclude other sialyltransferase activities. Thus, simple and specific methods for measuring plasma ST6Gal I had been unavailable. Here, we developed two kinds of sandwich enzyme-linked immunosorbent assay (ELISA) systems that specifically detect the soluble cleaved form of ST6Gal I in plasma. In one sandwich ELISA, we detected rat specific sequence, EFQMPK, which is N-terminus of soluble ST6Gal I. In the other sandwich ELISA, we detected internal common sequence among rat, mouse and human ST6Gal I in plasma (M2 ELISA). Using the M2 ELISA, we observed that elevation of plasma ST6Gal I was much faster than elevation of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a carbon tetrachloride (CCl{sub 4})-induced mouse liver injury model. Our data suggest that these ELISA systems are very useful tools for measuring plasma ST6Gal I, which represents a potential biomarker for diagnosing hepatic diseases.

  14. 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 sp...

  15. A novel electrochemical aptamer-antibody sandwich assay for lysozyme detection.

    Science.gov (United States)

    Ocaña, Cristina; Hayat, Akhtar; Mishra, Rupesh; Vasilescu, Alina; del Valle, Manel; Marty, Jean-Louis

    2015-06-21

    In this paper, we have reported a novel electrochemical aptamer-antibody based sandwich biosensor for the detection of lysozyme. In the sensing strategy, an anti-lysozyme aptamer was immobilized onto the carbon electrode surface by covalent binding via diazonium salt chemistry. After incubating with a target protein (lysozyme), a biotinylated antibody was used to complete the sandwich format. The subsequent additions of avidin-alkaline phosphatase as an enzyme label, and a 1-naphthyl phosphate substrate (1-NPP) allowed us to determine the concentration of lysozyme (Lys) via Differential Pulse Voltammetry (DPV) of the generated enzyme reaction product, 1-naphthol. Using this strategy, a wide detection range from 5 fM to 5 nM was obtained for a target lysozyme, with a detection limit of 4.3 fM. The control experiments were carried out by using bovine serum albumin (BSA), cytochrome c and casein. The results showed that the proposed biosensor had good specificity, stability and reproducibility for lysozyme analysis. In addition, the biosensor was applied for detecting lysozyme in spiked wine samples, and very good recovery rates were obtained in the range from 95.2 to 102.0% for lysozyme detection. This implies that the proposed sandwich biosensor is a promising analytical tool for the analysis of lysozyme in real samples.

  16. Sound transmission loss of composite sandwich panels

    Science.gov (United States)

    Zhou, Ran

    Light composite sandwich panels are increasingly used in automobiles, ships and aircraft, because of the advantages they offer of high strength-to-weight ratios. However, the acoustical properties of these light and stiff structures can be less desirable than those of equivalent metal panels. These undesirable properties can lead to high interior noise levels. A number of researchers have studied the acoustical properties of honeycomb and foam sandwich panels. Not much work, however, has been carried out on foam-filled honeycomb sandwich panels. In this dissertation, governing equations for the forced vibration of asymmetric sandwich panels are developed. An analytical expression for modal densities of symmetric sandwich panels is derived from a sixth-order governing equation. A boundary element analysis model for the sound transmission loss of symmetric sandwich panels is proposed. Measurements of the modal density, total loss factor, radiation loss factor, and sound transmission loss of foam-filled honeycomb sandwich panels with different configurations and thicknesses are presented. Comparisons between the predicted sound transmission loss values obtained from wave impedance analysis, statistical energy analysis, boundary element analysis, and experimental values are presented. The wave impedance analysis model provides accurate predictions of sound transmission loss for the thin foam-filled honeycomb sandwich panels at frequencies above their first resonance frequencies. The predictions from the statistical energy analysis model are in better agreement with the experimental transmission loss values of the sandwich panels when the measured radiation loss factor values near coincidence are used instead of the theoretical values for single-layer panels. The proposed boundary element analysis model provides more accurate predictions of sound transmission loss for the thick foam-filled honeycomb sandwich panels than either the wave impedance analysis model or the

  17. The use of monoclonal antibodies in competitive ELISA for the detection of antibodies to rinderpest and peste des petits ruminants viruses

    International Nuclear Information System (INIS)

    Anderson, J.; McKay, J.A.; Butcher, R.N.

    1991-01-01

    A monoclonal antibody against the haemagglutinin of rinderpest virus has been used in a competitive ELISA (C-ELISA) for the detection of antibodies to rinderpest virus in cattle, sheep, goat and game sera. Unlike the indirect ELISA and the virus neutralisation test (VNT), the C-ELISA detects only antibodies to rinderpest virus and gives no cross-reactivity with antibodies to peste des petits ruminants (PPR) virus. Antibodies to a wide range of strains of rinderpest virus have been detected using this assay, suggesting its suitability for both sero-monitoring and sero-surveillance. Analysis of C-ELISA results from the examination of field sera shows a much greater separation of negative and positive populations as compared to the indirect ELISA. A further monoclonal antibody against the H protein of PPR has also been found suitable for use in a C-ELISA for the detection of antibodies to PPR virus. The use of these two C-ELISA's has made possible rapid differential sero-diagnosis without recourse to cross-VNT testing. The use of monoclonal antibody-based assays will allow much greater standardisation of rinderpest and PPR diagnosis, and following field-trials the C-ELISA will replace the indirect ELISA for sero-monitoring throughout the Pan African Rinderpest Campaign. (author). 3 refs, 6 figs, 1 tab

  18. 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...

  19. Elisa technology consolidation study overview

    Science.gov (United States)

    Fitzsimons, E. D.; Brandt, N.; Johann, U.; Kemble, S.; Schulte, H.-R.; Weise, D.; Ziegler, T.

    2017-11-01

    The eLISA (evolved Laser Interferometer Space Antenna) mission is an ESA L3 concept mission intended to detect and characterise gravitational radiation emitted from astrophysical sources [1]. Current designs for eLISA [2] are based on the ESA study conducted in 2011 to reformulate the original ESA/NASA LISA concept [3] into an ESA-only L1 candidate named NGO (New Gravitational Observatory) [4]. During this brief reformulation period, a number of significant changes were made to the baseline LISA design in order to create a more costeffective mission. Some of the key changes implemented during this reformulation were: • A reduction in the inter satellite distance (the arm length) from 5 Gm to 1 Gm. • A reduction in the diameter of the telescope from 40 cm to 20 cm. • A reduction in the required laser power by approximately 40%. • Implementation of only 2 laser arms instead of 3. Many further simplifications were then enabled by these main design changes including the elimination of payload items in the two spacecraft (S/C) with no laser-link between them (the daughter S/C), a reduction in the size and complexity of the optical bench and the elimination of the Point Ahead Angle Mechanism (PAAM), which corrects for variations in the pointing direction to the far S/C caused by orbital dynamics [4] [5]. In the run-up to an L3 mission definition phase later in the decade, it is desirable to review these design choices and analyse the inter-dependencies and scaling between the key mission parameters with the goal of better understanding the parameter space and ensuring that in the final selection of the eLISA mission parameters the optimal balance between cost, complexity and science return can be achieved.

  20. 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 molecular....../mL, these values being significantly different from the normal range (p ELISA was superior to commercially available assays for PICP and osteocalcin in separation between healthy controls and patients with osteomalaci. Udgivelsesdato: 1996-Aug...

  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. ELISA for detection of variant rabbit haemorrhagic disease virus RHDV2 antigen in liver extracts.

    Science.gov (United States)

    Dalton, K P; Podadera, A; Granda, V; Nicieza, I; Del Llano, D; González, R; de Los Toyos, J R; García Ocaña, M; Vázquez, F; Martín Alonso, J M; Prieto, J M; Parra, F; Casais, R

    2018-01-01

    The emergence and rapid spread of variant of the rabbit hemorrhagic disease virus (RHDV2) require new diagnostic tools to ensure that efficient control measures are adopted. In the present study, a specific sandwich enzyme-linked immunosorbent assay (ELISA) for detection of RHDV2 antigens in rabbit liver homogenates, based on the use of an RHDV2-specific monoclonal antibody (Mab) 2D9 for antigen capture and an anti-RHDV2 goat polyclonal antibody (Pab), was developed. This ELISA was able to successfully detect RHDV2 and RHDV2 recombinant virions with high sensitivity (100%) and specificity (97.22%). No cross-reactions were detected with RHDV G1 viruses while low cross-reactivity was detected with one of the RHDVa samples analyzed. The ELISA afforded good repeatability and had high analytical sensitivity as it was able to detect a dilution 1:163,640 (6.10ng/mL) of purified RHDV-N11 VLPs, which contained approximately 3.4×10 8 molecules/mL particles. The reliable discrimination between closely related viruses is crucial to understand the epidemiology and the interaction of co-existing pathogens. In the work described here we design and validate an ELISA for laboratory based, specific, sensitive and reliable detection of RHDVb/RHDV2. This ELISA is a valuable, specific virological tool for monitoring virus circulation, which will permit a better control of this disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. 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.

  4. Experimental formability analysis of bondal sandwich sheet

    Science.gov (United States)

    Kami, Abdolvahed; Banabic, Dorel

    2018-05-01

    Metal/polymer/metal sandwich sheets have recently attracted the interests of industries like automotive industry. These sandwich sheets have superior properties over single-layer metallic sheets including good sound and vibration damping and light weight. However, the formability of these sandwich sheets should be enhanced which requires more research. In this paper, the formability of Bondal sheet (DC06/viscoelastic polymer/DC06 sandwich sheet) was studied through different types of experiments. The mechanical properties of Bondal were determined by uniaxial tensile tests. Hemispherical punch stretching and hydraulic bulge tests were carried out to determine the forming limit diagram (FLD) of Bondal. Furthermore, cylindrical and square cup drawing tests were performed in dry and oil lubricated conditions. These tests were conducted at different blank holding forces (BHFs). An interesting observation about Bondal sheet deep drawing was obtaining of higher drawing depths at dry condition in comparison with oil-lubricated condition.

  5. Natural fabric sandwich laminate composites: development and ...

    Indian Academy of Sciences (India)

    3Department of Production Technology, MIT Campus, Anna University, Chennai 600044, India. MS received ... In this work, eco-friendly natural fabric sandwich laminate (NFSL) composites are formulated using ... and eco-friendly quality [22].

  6. Adhesion aspects of polyurethane foam sandwich panels.

    OpenAIRE

    Ng, Simon L.

    2016-01-01

    Sandwich panels, polyurethane foam sandwiched between two sheets of steel, form the walls and roofs in the construction of buildings. ArcelorMittal is a manufacturer of the steel as well as these finished panels. For this project they combined with a supplier of the polyurethane foams, Huntsman Polyurethanes, to joint-fund a research project investigating the fundamental mechanisms of adhesion, as well as the causes of failures in the product which manifests primarily in two different ways...

  7. Development and primary application of ELISA method for detecting residual calf serum protein

    International Nuclear Information System (INIS)

    Li Hua; Yu Jiankun; Hong Chao; Long Ruixiang; Zhai Yougang; Xu Qiongfang; Cui Pingfang; Ding Xuefeng; Xie Zhongping

    2005-01-01

    To develop a new DAS-ELISA (double antibody sandwich ELISA) kit for detecting residual calf serum protein (CSP) in vaccines, calf sera from different district were pooled and used to immunize rabbits and hens respectively. Then, the IgY from yolk and the anti-CSP IgG from rabbit were separated and purified. The purified IgY was used as the coating antibody, and purified rabbit anti-CSP IgG was labeled by HRP. The optimal concentration of IgY was 25-30 μg/mL. The coating buffer was 0.01mol/L PBS(pH7.4) containing 0.4% glutin. The optimal dilutions of HRP-IgG were from 1:2000 to 1:3000. The sensitivity of this ELISA method was higher (up to 2.5μg/mL) than that of current RPHA, the variation coefficient was about 6.3%-9.4%, and the recovery rate was 90.4%-112.8%. Furthermore, there was no cross-reaction with sera of pig, monkey and guinea pig. Twenty lots of vaccines with Al(OH) 3 or without Al(OH) 3 were tested by ELISA and RPHA respectively. The results proved that the adjuvant of Al(OH) 3 had fewer influence on ELISA than on RPHA, the variation of PRHA among different lots of vaccines was more significant than ELISA. The ELISA method is a highly sensitive and useful method to detect CSP in vaccines. (authors)

  8. ELISA analysis of soybean trypsin inhibitors in processed foods.

    Science.gov (United States)

    Brandon, D L; Bates, A H; Friedman, M

    1991-01-01

    Soybean proteins are widely used in human foods in a variety of forms, including infant formulas, flour, protein concentrates, protein isolates, soy sauces, textured soy fibers, and tofu. The presence of inhibitors of digestive enzymes in soy proteins impairs the nutritional quality and possibly the safety of soybeans and other legumes. Processing, based on the use of heat or fractionation of protein isolates, does not completely inactivate or remove these inhibitors, so that residual amounts of inhibitors are consumed by animals and humans. New monoclonal antibody-based immunoassays can measure low levels of the soybean Kunitz trypsin inhibitor (KTI) and the Bowman-Birk trypsin and chymotrypsin inhibitor (BBI) and the Bowman-Birk foods. The enzyme-linked immunosorbent assay (ELISA) was used to measure the inhibitor content of soy concentrates, isolates, and flours, both heated and unheated; a commercial soy infant formula; KTI and BBI with rearranged disulfide bonds; browning products derived from heat-treatment of KTI with glucose and starch; and KTI exposed to high pH. The results indicate that even low inhibitor isolates contain significant amounts of specific inhibitors. Thus, infants on soy formula consume about 10 mg of KTI plus BBI per day. The immunoassays complement the established enzymatic assays of trypsin and chymotrypsin inhibitors, and have advantages in (a) measuring low levels of inhibitors in processed foods; and (b) differentiating between the Kunitz and Bowman-Birk inhibitors. The significance of our findings for food safety are discussed.

  9. Quantitative Detection of Horse Contamination in Cooked Meat Products by ELISA.

    Science.gov (United States)

    Thienes, Cortlandt P; Masiri, Jongkit; Benoit, Lora A; Barrios-Lopez, Brianda; Samuel, Santosh A; Cox, David P; Dobritsa, Anatoly P; Nadala, Cesar; Samadpour, Mansour

    2018-05-01

    Concerns about the contamination of meat products with horse meat and new regulations for the declaration of meat adulterants have highlighted the need for a rapid test to detect horse meat adulteration. To address this need, Microbiologique, Inc., has developed a sandwich ELISA that can quantify the presence of horse meat down to 0.1% (w/w) in cooked pork, beef, chicken, goat, and lamb meats. This horse meat authentication ELISA has an analytical sensitivity of 0.000030 and 0.000046% (w/v) for cooked and autoclaved horse meat, respectively, and an analytical range of quantitation of 0.05-0.8% (w/v) in the absence of other meats. The assay is rapid and can be completed in 1 h and 10 min. Moreover, the assay is specific for cooked horse meat and does not demonstrate any cross-reactivity with xenogeneic cooked meat sources.

  10. Development, standardisation and validation of ELISA methods to improve the control of trypanosomosis

    International Nuclear Information System (INIS)

    Rebeski, D.E.; Winger, E.M.; Robinson, M.M.; Dwinger, R.H.; Crowther, J.R.

    2000-01-01

    During the period from 1995 to 2000, comprehensive laboratory and field studies on enzyme-linked immunosorbent assay (ELISA) methods for detection of trypanosomal antibodies and antigens were undertaken to improve the proficiency of diagnostic laboratories involved in control of trypanosomosis in the tropics. The work was initiated by the FAO/IAEA through the Coordinated Research Programme D3.20.13 and undertaken in close collaboration with Research Agreement Holders and Research Contract Holders. Initially, the CRP facilitated the field evaluation of three direct sandwich antigen detection ELISAs based on monoclonal antibodies. Diagnostic laboratories were supported with ELISA equipment, disposables, and training. ELISA reagents were produced in sufficient quantities and distributed in a standardised kit format. As a result of the laboratory and field evaluation studies, the assays were found unreliable for trypanosomosis control and rejected for routine use in diagnostic laboratories. At that time, no standardised ELISA system was available for trypanosomosis that was considered suitable for distribution and use under tropical conditions. Through the CRP, a new generation of standardised antibody ELISAs were developed and established using a novel approach, namely the use of antigen-precoated ELISA plates. In addition, the potential of native and denatured trypanosomal antigens as diagnostic candidates was examined. In-house and field evaluation studies in the tropics demonstrated that a reasonable robustness with an acceptable diagnostic assay proficiency was achieved by means of utilising plates precoated with denatured antigens. Moreover, a data charting method for continuous monitoring of the operational performance of the ELISAs was developed and established. It was routinely used as remote control and follow up tool saving the need for costly expert missions to the diagnostic laboratories during the assay validation period. In parallel, preliminary studies

  11. 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...

  12. 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.…

  13. An enzyme-linked immunosorbent assay (ELISA) for quantification of mouse surfactant protein D (SP-D)

    DEFF Research Database (Denmark)

    Hansen, Soren; Schmidt, Vivi; Steffensen, Maria Abildgaard

    2008-01-01

    characterized and validated for use in sandwich enzyme-linked immunosorbent assay (ELISA). Based on two of these, we established an ELISA that allows for measurements of mouse SP-D in various body fluids. The final ELISA was optimized and calibrated with a standard of purified recombinant mouse SP-D, which......Surfactant protein D (SP-D) is a pattern recognition molecule of the collectin family of C-type lectins. It is found in the airways and at mucosal surfaces. SP-D is part of the innate immune system where it neutralizes and leads to elimination of microorganisms. It regulates the functions of other...... innate immune cells, such as macrophages and neutrophils. It also modulates the adaptive immune response by interacting with antigen-presenting cells and T cells. Monoclonal anti-mouse-SP-D antibodies were raised from SP-D deficient mice using recombinant SP-D as antigen. Ten monoclonal antibodies were...

  14. An enzyme-linked immunosorbent assay (ELISA) for quantification of human collectin 11 (CL-11, CL-K1)

    DEFF Research Database (Denmark)

    Selman, L; Henriksen, M L; Brandt, J

    2012-01-01

    -associated serine protease 1 (MASP-1) and/or MASP-3 in circulation. Mutation in the CL-11 gene was recently associated with the developmental syndrome 3MC. In the present study, we established and thoroughly validated a sandwich enzyme-linked immunosorbent assay (ELISA) based on two different monoclonal antibodies....... The assay is highly sensitive, specific and shows excellent quantitative characteristics such as reproducibility, dilution linearity and recovery (97.7-104%). The working range is 0.15-34 ng/ml. The CL-11 concentration in two CL-11-deficient individuals affected by the 3MC syndrome was determined...... and thawing to a certain extent did not influence the ELISA. This ELISA offers a convenient and reliable method for studying CL-11 levels in relation to a variety of human diseases and syndromes....

  15. 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.

  16. Behavior of sandwich panels in a fire

    Science.gov (United States)

    Chelekova, Eugenia

    2018-03-01

    For the last decades there emerged a vast number of buildings and structures erected with the use of sandwich panels. The field of application for this construction material is manifold, especially in the construction of fire and explosion hazardous buildings. In advanced evacu-ation time calculation methods the coefficient of heat losses is defined with dire regard to fire load features, but without account to thermal and physical characteristics of building envelopes, or, to be exact, it is defined for brick and concrete walls with gross heat capacity. That is why the application of the heat loss coefficient expression obtained for buildings of sandwich panels is impossible because of different heat capacity of these panels from the heat capacities of brick and concrete building envelopes. The article conducts an analysis and calculation of the heal loss coefficient for buildings and structures of three layer sandwich panels as building envelopes.

  17. Buckling Analysis of Edge Cracked Sandwich Plate

    Directory of Open Access Journals (Sweden)

    Rasha Mohammed Hussein

    2016-07-01

    Full Text Available This work presents mainly the buckling load of sandwich plates with or without crack for different cases. The buckling loads are analyzed experimentally and numerically by using ANSYS 15. The experimental investigation was to fabricate the cracked sandwich plate from stainless steel and PVC to find mechanical properties of stainless steel and PVC such as young modulus. The buckling load for different aspect ratio, crack length, cracked location and plate without crack found. The experimental results were compared with that found from ANSYS program. Present of crack is decreased the buckling load and that depends on crack size, crack location and aspect ratio.

  18. AA, sandwich line with magnetic horn

    CERN Multimedia

    CERN PhotoLab

    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.

  19. Buckling driven debonding in sandwich columns

    DEFF Research Database (Denmark)

    Østergaard, Rasmus Christian

    2008-01-01

    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......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...

  20. Long sandwich modules for photon veto detectors

    International Nuclear Information System (INIS)

    Yershov, N.; Khabibullin, M.; Kudenko, Yu.; Littenberg, L.; Mayatski, V.; Mineev, O.

    2005-01-01

    Long lead-scintillator sandwich modules developed for the BNL experiment KOPIO are described. The individual 4 m long module consists of 15 layers of 7 mm thick extruded scintillator and 15 layers of 1 mm lead absorber. Readout is implemented via WLS fibers glued into grooves in a scintillator with 7 mm spacing and viewed from both ends by the phototubes. Time resolution of 300 ps for cosmic MIPs was obtained. Light output stability monitored for 2 years shows no degradation beyond the measurement errors. A 4 m long C-bent sandwich module was also manufactured and tested

  1. 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.

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

    Science.gov (United States)

    Parma, Y. R.; Chacana, P. A.; Lucchesi, P. M. A.; Rogé, A.; Granobles Velandia, C. V.; Krüger, A.; Parma, A. E.; Fernández-Miyakawa, M. E.

    2012-01-01

    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-Stx2B 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 115 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 two 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. PMID:22919675

  3. A polyclonal antibody based immunoassay detects seven subtypes of Shiga toxin 2 produced by Escherichia coli in human and environmental samples.

    Directory of Open Access Journals (Sweden)

    Xiaohua He

    Full Text Available BACKGROUND: Shiga toxin-producing Escherichia coli (STEC are frequent causes of severe human diseases ranging from diarrhea to hemolytic uremic syndrome. The existing strategy for detection of STEC relies on the unique sorbitol-negative fermentation property of the O157 strains, the most commonly identified serotype has been E. coli O157. It is becoming increasingly evident, however, that numerous non-O157 STEC serotypes also cause outbreaks and severe illnesses. It is necessary to have new methods that are capable of detecting all STEC strains. METHODS AND FINDINGS: Here we describe the development of a sandwich ELISA assay for detecting both O157 and non-O157 STECs by incorporating a novel polyclonal antibody (pAb against Stx2. The newly established immunoassay was capable of detecting Stx2a spiked in environmental samples with a limit of detection between 10 and 100 pg/mL in soil and between 100 and 500 pg/mL in feces. When applied to 36 bacterial strains isolated from human and environmental samples, this assay detected Stx2 in all strains that were confirmed to be stx2-positive by real-time PCR, demonstrating a 100% sensitivity and specificity. CONCLUSIONS: The sandwich ELISA developed in this study will enable any competent laboratory to identify and characterize Stx2-producing O157 and non-O157 strains in human and environmental samples, resulting in rapid diagnosis and patient care. The results of epitope mapping from this study will be useful for further development of a peptide-based antibody and vaccine.

  4. Compressive properties of sandwiches with functionally graded

    Indian Academy of Sciences (India)

    The compressive behaviour of a new class of sandwich composite made up of jute fiber reinforced epoxy skins and piece-wise linear fly ash reinforced functionally graded (FG) rubber core is investigated in flat-wise mode. FG samples are prepared using conventional casting technique. Presence of gradation is quantified ...

  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. AA, sandwich line with magnetic horn

    CERN Multimedia

    CERN PhotoLab

    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.

  7. 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...

  8. A novel sandwich enzyme-linked immunosorbent assay with covalently bound monoclonal antibody and gold probe for sensitive and rapid detection of bovine β-lactoglobulin.

    Science.gov (United States)

    He, Shengfa; Li, Xin; Wu, Yong; Wu, Shandong; Wu, Zhihua; Yang, Anshu; Tong, Ping; Yuan, Juanli; Gao, Jinyan; Chen, Hongbing

    2018-06-01

    Bovine milk is a recognized allergenic food source with β-lactoglobulin (BLG) as its major allergen. Reliable detection of BLG epitopes can, therefore, be a useful marker for the presence of milk in processed food products, and for potential allergenicity. At the present, enzyme-linked immunosorbent assays (ELISA) for the detection of BLG are time-consuming and generally not specific to BLG IgE epitopes. In this study, the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-activated anti-BLG IgE epitope monoclonal antibody (mAb 1G9) was covalently bound onto the KOH-treated microtiter plate surface. Using this mAb-bound plate in sandwich combination with biotinylated anti-BLG polyclonal antibody-labeled gold nanoparticles, a linear dynamic range between 31.25 and 64 × 10 3  ng mL -1 with a limit of detection for BLG of 0.49 ng mL -1 was obtained, which is 32 times wider and 16 times more sensitive than conventional sandwich ELISA (sELISA). Total recovery of BLG in spiked food samples was found, without matrix effects. Also in partially hydrolyzed infant formulas, the allergenic BLG residues were detected quantitatively. Compared with conventional and commercial BLG detection sELISAs, our sELISA is reliable, highly BLG epitope-specific, user-friendly, and time-saving and allows accurate detection of potentially allergenic residues in different types of processed foods. This improved sELISA protocol can be easily extended to detect other well-identified and characterized food allergens. Graphical abstract IgE epitope mAb-bound plate in sandwich combination with gold probe for sensitive and rapid detection of bovine β-lactoglobulin and its potentially allergenic residues.

  9. Field trial of brucellosis competitive ELISA

    International Nuclear Information System (INIS)

    Perez, B.; Rojas, M.

    1998-01-01

    2990 sera samples from cattle were tested for antibodies to Brucella abortus using 8 serological tests for. The tests used were Rose Bengal (RBT), Buffer Plate Agglutination Test (BPAT), Complement Fixation (CFT), 2 Indirect and 2 Competitive Enzyme Linked Immunosorbent Assays (ELISA). Bacteriological evaluation from milk was done also. All tests were compared with respect to diagnostic specificity in vaccinated herds which were considered to be Brucella-free. The diagnostic specificity of the Indirect and Competitive ELISA was greater than 99,8%. Estimates of relative sensitivity were obtained from infected herds. The diagnostic sensitivity of the Indirect ELISA was greater than 95,8% and for the Competitive ELISA between 98,8 and 100 %, the last value refers to the Competitive ELISA Prototype II (SLPS antigen/M84 Mab), which was found highly suitable to differentiate vaccinated from brucella-infected cattle. The use of C-ELISA II for monitoring bovine populations under an eradication programme is recommended. (author)

  10. Comparison between microscopic examination, ELISA and quantitative buffy coat analysis in the diagnosis of falciparum malaria in an endemic population.

    Science.gov (United States)

    Tanpradist, S; Tharavanij, S; Yamokgul, P; Bualombai, P; Wongchotigul, V; Singhasivanon, P; Patarapotikul, J; Thammapalerd, N; Prasittisuk, C; Tantanasrikul, S

    1995-03-01

    Monoclonal antibody-based ELISA and QBC (quantitative buffy coat analysis) were tested in two endemic areas with low and high incidence of malaria in Kanchanaburi Province, West Thailand with annual parasite incidence in 1992 of 119 and 5 per 1,000 population, respectively. The numbers of individuals positive by thick blood film examination (TBF) for P. falciparum with or without P. vivax, and P. vivax only were 82 and 69, respectively. The detection limit of ELISA was 10 parasites/10(6) red blood cells (RBC) (0.001% parasitemia). Of 1,095 individuals involved in the study at the beginning of the study, ELISA showed sensitivity, specificity, positive predictive value and negative predictive value of 78.1%, 94.9%, 72% and 98.1%, respectively. Nine of 18 (50%) TBF-positive but ELISA-positive individuals had parasitemia of less than 10 parasites/10(6) RBC. High and low incidence areas did not affect the validity of our result. Regression analysis showed good correlation between log parasitemia and ELISA percent OD increase (Y = 0 + 64.9*logX, r = 0.65), and agreement between TBF and ELISA results was 95.9%. In a fortnightly follow-up, in 82 TBF-positive individuals, both ELISA and TBF positive rates correlatively declined with agreement of 96.3%. With samples taken on the first day of the study, the TBF and QBC results were also correlated with agreement of 95.8% for P. falciparum, 95.6% for P. vivax. During 8 week follow-up involving altogether 191 samples, agreement between TBF and QBC results were 87.4% for P. falciparum. QBC detected more cases with P. falciparum infections but detected smaller number of cases with P. vivax infections.

  11. Extension of the ELISA method to the measurement of the specific radioactivity of viruses in crude cellular extracts

    Energy Technology Data Exchange (ETDEWEB)

    Konate, G; Fritig, B [Institut de Biologie Moleculaire et Cellulaire, 67-Strasbourg (France). Lab. de Virologie

    1983-06-01

    The double-antibody sandwich method of ELISA, which allows accurate quantitative determination of plant viruses, was extended to a radiochemical procedure which permits direct measurement of the specific radioactivity of virus labelled in vivo and present in very crude plant homogenates. Evidence is presented showing that 20 to 50% of the virus introduced in the polystyrene wells during the antigen incubation step could be trapped in the sandwich. The percentage of virus bound increased with the concentration of the coating antibody and was almost proportional to the concentration of the antigen and to the incubation time of the antigens. Complete dissociation of the double-antibody sandwich was achieved by incubation with 0.2 M KOH or NaOH (pH 13.3), and the label carried by the virus was measured by scintillation counting of the solubilization fluid. The ratio infected/healthy was much higher for the radiochemical procedure than for the immunosorbent assay itself since binding of the virus to the coating antibody was not accompanied by any nonspecific trapping of radioactive contaminants in the double-antibody sandwich. The procedure was highly sensitive since the background corresponded to the scintillation counting background. The detection of the label carried by tobacco mosaic virus was possible when the tobacco samples contained at least 5 ng of virus carrying a label as low as 40 dpm /sup 3/H or 20 dpm /sup 14/C.

  12. Detection of Antibodies to U.S. Isolates of Avian Pneumovirus by a Recombinant Nucleocapsid Protein-Based Sandwich Enzyme-Linked Immunosorbent Assay

    OpenAIRE

    Gulati, Baldev R.; Munir, Shirin; Patnayak, Devi P.; Goyal, Sagar M.; Kapur, Vivek

    2001-01-01

    The nucleocapsid (N) protein of subgroup C (United States-specific) avian pneumovirus (APV/US) was expressed in Escherichia coli, and antibodies to the recombinant N protein were shown to specifically recognize the ≈47-kDa N protein of APV/US by Western immunoblot analysis. The recombinant APV/US N protein was used in a sandwich-capture enzyme-linked immunosorbent assay (ELISA), and the resulting assay was found to be more sensitive and specific than the routine indirect ELISA for the detecti...

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

    OpenAIRE

    Parma, Y. R.; Chacana, P. A.; Lucchesi, P. M. A.; Rogé, A.; Granobles Velandia, C. V.; Krüger, A.; Parma, A. E.; Fernández-Miyakawa, M. E.

    2012-01-01

    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-St...

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

    OpenAIRE

    Yanil R Parma; Pablo A Chacana; Paula María Alejandra Lucchesi; Ariel eRoge; Claudia V Granobles Velandia; Alejandra eKrüger; Alejandra eKrüger; Alberto E. Parma; Mariano Enrique Fernandez Miyakawa

    2012-01-01

    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-St...

  15. Characterization of ELISA Antibody-Antigen Interaction using Footprinting-Mass Spectrometry and Negative Staining Transmission Electron Microscopy

    Science.gov (United States)

    Lin, Margaret; Krawitz, Denise; Callahan, Matthew D.; Deperalta, Galahad; Wecksler, Aaron T.

    2018-05-01

    We describe epitope mapping data using multiple covalent labeling footprinting-mass spectrometry (MS) techniques coupled with negative stain transmission electron microscopy (TEM) data to analyze the antibody-antigen interactions in a sandwich enzyme-linked immunosorbant assay (ELISA). Our hydroxyl radical footprinting-MS data using fast photochemical oxidation of proteins (FPOP) indicates suppression of labeling across the antigen upon binding either of the monoclonal antibodies (mAbs) utilized in the ELISA. Combining these data with Western blot analysis enabled the identification of the putative epitopes that appeared to span regions containing N-linked glycans. An additional structural mapping technique, carboxyl group footprinting-mass spectrometry using glycine ethyl ester (GEE) labeling, was used to confirm the epitopes. Deglycosylation of the antigen resulted in loss of potency in the ELISA, supporting the FPOP and GEE labeling data by indicating N-linked glycans are necessary for antigen binding. Finally, mapping of the epitopes onto the antigen crystal structure revealed an approximate 90° relative spatial orientation, optimal for a noncompetitive binding ELISA. TEM data shows both linear and diamond antibody-antigen complexes with a similar binding orientation as predicted from the two footprinting-MS techniques. This study is the first of its kind to utilize multiple bottom-up footprinting-MS techniques and TEM visualization to characterize the monoclonal antibody-antigen binding interactions of critical reagents used in a quality control (QC) lot-release ELISA. [Figure not available: see fulltext.

  16. Characterization of ELISA Antibody-Antigen Interaction using Footprinting-Mass Spectrometry and Negative Staining Transmission Electron Microscopy

    Science.gov (United States)

    Lin, Margaret; Krawitz, Denise; Callahan, Matthew D.; Deperalta, Galahad; Wecksler, Aaron T.

    2018-03-01

    We describe epitope mapping data using multiple covalent labeling footprinting-mass spectrometry (MS) techniques coupled with negative stain transmission electron microscopy (TEM) data to analyze the antibody-antigen interactions in a sandwich enzyme-linked immunosorbant assay (ELISA). Our hydroxyl radical footprinting-MS data using fast photochemical oxidation of proteins (FPOP) indicates suppression of labeling across the antigen upon binding either of the monoclonal antibodies (mAbs) utilized in the ELISA. Combining these data with Western blot analysis enabled the identification of the putative epitopes that appeared to span regions containing N-linked glycans. An additional structural mapping technique, carboxyl group footprinting-mass spectrometry using glycine ethyl ester (GEE) labeling, was used to confirm the epitopes. Deglycosylation of the antigen resulted in loss of potency in the ELISA, supporting the FPOP and GEE labeling data by indicating N-linked glycans are necessary for antigen binding. Finally, mapping of the epitopes onto the antigen crystal structure revealed an approximate 90° relative spatial orientation, optimal for a noncompetitive binding ELISA. TEM data shows both linear and diamond antibody-antigen complexes with a similar binding orientation as predicted from the two footprinting-MS techniques. This study is the first of its kind to utilize multiple bottom-up footprinting-MS techniques and TEM visualization to characterize the monoclonal antibody-antigen binding interactions of critical reagents used in a quality control (QC) lot-release ELISA. [Figure not available: see fulltext.

  17. Immunodiagnosis of Human Fascioliasis by an Enzyme-Linked Immunosorbent Assay (ELISA) and a Micro-ELISA

    OpenAIRE

    Carnevale, Silvana; Rodríguez, Mónica I.; Santillán, Graciela; Labbé, Jorge H.; Cabrera, Marta G.; Bellegarde, Enrique J.; Velásquez, Jorge N.; Trgovcic, Jorge E.; Guarnera, Eduardo A.

    2001-01-01

    Enzyme-linked immunosorbent assay (ELISA) and micro-ELISA were evaluated for their ability to detect anti-Fasciola hepatica antibodies in humans by using excretory-secretory antigen. The sensitivity of each method was 100%, but the specificity was 100% for ELISA and 97% for micro-ELISA. The micro-ELISA could be used as a screening assay and ELISA could be used as a confirmatory method for the serodiagnosis of human fascioliasis.

  18. Sandwich veto detector at COMPASS experiment

    International Nuclear Information System (INIS)

    Sarkar, S.; Dasgupta, S.S.; Calcutta-COMPASS group

    2010-01-01

    This paper presents the newly build Sandwich Detector for 190 GeV hadron run of COMPASS Experiment at CERN. The technical details and the testing procedures are included to highlight the physics objective of the installation. Single electron detection techniques has been developed and used to scale the performance of the detector. This analysis can predict the number of single electrons per MIP at the scintillation detector. (author)

  19. Failure modes of composite sandwich beams

    OpenAIRE

    Gdoutos E.; Daniel I.M.

    2008-01-01

    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 wit...

  20. 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.

  1. 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.

  2. Sandwich design for ships and railway wagons

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, K.-A. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Aeronautics

    2000-07-01

    In Sweden we have long experience of different types of vehicles and ships in sandwich construction, especially for Navy ships, such as minesweepers, mine-counter-measure-vessels and corvettes. As face materials mostly GRP and FRP have been used, but also metallic materials of Al-alloys, coated carbon steel and stainless steel. Core materials have usually been cellular plastic foams of cross-linked PVC, but also extruded PS, PUR, PEI and PMI. A lot of different continuous and discontinuous manufacturing processes are used. Vacuum assisted infusion is used in the last years, because it is a closed process, gives high fibre content and a good quality of the laminates. Sandwich design has mainly been used in the transportation area, where lightweight design is needed to give higher performance and load bearing capacity. The use of sandwich will give high stiffness- and strength-to weight ratio. These are in most cases not enough from economic point of view, but even other integrated functions must be considered, i.e. insulation, energy consumption, damping, less components, lower manufacturing costs, low maintenance, signature effects (military) etc. (orig.)

  3. Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Konstantinou, George N

    2017-01-01

    Food allergy is a public health concern especially after recognizing its constantly increased prevalence and severity. Despite careful reading of food ingredient statements, food allergic individuals may experience reactions caused by "hidden", "masked", or "contaminated" proteins that are known major allergens. Many techniques have been developed to detect even small traces of food allergens, for clinical or laboratory purposes. Enzyme-linked immunosorbent assay (ELISA) is one of the best validated and most routinely used immunoassay in allergy research, in allergy diagnosis in allergy-related quality control in various industries. Although as a technique it has been implemented for the last 45 years, the evolution in biochemistry allowed the development of ultrasensitive ELISA variations that are capable of measuring quantities in the scale of picograms, rendering ELISA attractive, robust, and very famous.

  4. 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

    2015-01-01

    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. PMID:25993517

  5. 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.

  6. Specificity of Toxocara ELISA in tropical populations.

    Science.gov (United States)

    Lynch, N R; Wilkes, L K; Hodgen, A N; Turner, K J

    1988-05-01

    The diagnosis of human infection by Toxocara canis relies heavily upon serological tests, the specificity of which can be inadequate in regions of endemic helminthiasis. When different population groups of tropical Venezuela were evaluated using ELISA based upon Toxocara excretory-secretory antigen (TcESA), solid-phase adsorption of the sera with extracts of a wide variety of non-homologous parasites revealed the existence of significant cross-reactivity. This was effectively and conveniently overcome when the test sera were incubated in the presence of the soluble parasite extracts in a competitive inhibition ELISA. The mean reduction of ELISA values caused by pre-adsorption of the sera tested was 32.2%, and that caused by competitive inhibition was 42.3%, the effects of these two procedures being strongly correlated (r = 0.83). The magnitude of the reduction was inversely proportional to the actual ELISA value (r = -0.55), and ranged from a mean of 68.0% in sera from apparently healthy individuals of medium-high socio-economic level, down to 28.1% in heavily parasitized Amazon indians. Ascaris showed the greatest degree of cross-reactivity in these tests, although under conditions of competitive inhibition even sera with high levels of antibody against this parasite could be negative in Toxocara ELISA. Western blotting revealed a major 81,400 D component that was shared between Ascaris and TcESA. Our results indicate that the competitive inhibition of cross-reactivity by soluble non-homologous parasite extracts provides a convenient and economical means of increasing the specificity of ELISA for the determination of the seroprevalence of toxocariasis in tropical populations.

  7. Galactic binaries with eLISA

    OpenAIRE

    Nelemans, G.

    2013-01-01

    I review what eLISA will see from Galactic binaries -- double stars with orbital periods less than a few hours and white dwarf (or neutron star/black hole) components. I discuss the currently known binaries that are guaranteed (or verification) sources and explain why the expected total number of eLISA Galactic binaries is several thousand, even though there are large uncertainties in our knowledge of this population, in particular that of the interacting AM CVn systems. I very briefly sketch...

  8. Validation of the FAO/IAEA/PANAFTOSA ELISA kit for determination of antibodies against foot-and-mouth disease virus

    International Nuclear Information System (INIS)

    Maradei, E.; Pedemonte, A.

    1998-01-01

    A Liquid phase blocking sandwich ELISA (LPBE) for the detection of foot-and-mouth disease (FMD) antibodies, serotypes O, A and C was validated using sera from bovines free of antibodies and vaccinated bovines. This technique proved to be sensitive and specific for the study of these antibodies. This kit has been prepared by the Pan American Foot-and-Mouth Disease Center (PAHO/WHO) in collaboration with the Animal Production and Health Section of the Joint FAO/IAEA Division, Vienna, Austria and the Institute for Animal Health in Pirbright, United Kingdom. (author)

  9. 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)

  10. 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

  11. Development of antibody-based c-Met inhibitors for targeted cancer therapy

    Directory of Open Access Journals (Sweden)

    Lee D

    2015-02-01

    Full Text Available Dongheon Lee, Eun-Sil Sung, Jin-Hyung Ahn, Sungwon An, Jiwon Huh, Weon-Kyoo You Hanwha Chemical R&D Center, Biologics Business Unit, Daejeon, Republic of Korea Abstract: Signaling pathways mediated by receptor tyrosine kinases (RTKs and their ligands play important roles in the development and progression of human cancers, which makes RTK-mediated signaling pathways promising therapeutic targets in the treatment of cancer. Compared with small-molecule compounds, antibody-based therapeutics can more specifically recognize and bind to ligands and RTKs. Several antibody inhibitors of RTK-mediated signaling pathways, such as human epidermal growth factor receptor 2, vascular endothelial growth factor, epidermal growth factor receptor or vascular endothelial growth factor receptor 2, have been developed and are widely used to treat cancer patients. However, since the therapeutic options are still limited in terms of therapeutic efficacy and types of cancers that can be treated, efforts are being made to identify and evaluate novel RTK-mediated signaling pathways as targets for more efficacious cancer treatment. The hepatocyte growth factor/c-Met signaling pathway has come into the spotlight as a promising target for development of potent cancer therapeutic agents. Multiple antibody-based therapeutics targeting hepatocyte growth factor or c-Met are currently in preclinical or clinical development. This review focuses on the development of inhibitors of the hepatocyte growth factor/c-Met signaling pathway for cancer treatment, including critical issues in clinical development and future perspectives for antibody-based therapeutics. Keywords: hepatocyte growth factor, ligands, receptor tyrosine kinase, signaling pathway, therapeutic agent

  12. Creep of sandwich beams with metallic foam cores

    International Nuclear Information System (INIS)

    Kesler, O.; Crews, L.K.; Gibson, L.J.

    2003-01-01

    The steady state creep deflection rates of sandwich beams with metallic foam cores were measured and compared with analytical and numerical predictions of the creep behavior. The deflection rate depends on the geometry of the sandwich beam, the creep behavior of the foam core and the loading conditions (stress state, temperature). Although there was a considerable scatter in the creep data (both of the foams and of the sandwich beams made using them), the data for the sandwich beams were fairly well described by the analysis

  13. Creep of sandwich beams with metallic foam cores

    Energy Technology Data Exchange (ETDEWEB)

    Kesler, O.; Crews, L.K.; Gibson, L.J

    2003-01-20

    The steady state creep deflection rates of sandwich beams with metallic foam cores were measured and compared with analytical and numerical predictions of the creep behavior. The deflection rate depends on the geometry of the sandwich beam, the creep behavior of the foam core and the loading conditions (stress state, temperature). Although there was a considerable scatter in the creep data (both of the foams and of the sandwich beams made using them), the data for the sandwich beams were fairly well described by the analysis.

  14. Damage Tolerance of Resin Transfer Molded Composite Sandwich Constructions

    National Research Council Canada - National Science Library

    Vaidya, U

    1999-01-01

    .... The sandwich composite concepts considered in this study possessed the feasibility to improve the transverse stiffness, provide enhanced damage resistance/tolerance to impact and functionality...

  15. Low Velocity Impact Properties of Aluminum Foam Sandwich Structural Composite

    Directory of Open Access Journals (Sweden)

    ZHAO Jin-hua

    2018-01-01

    Full Text Available Sandwich structural composites were prepared by aluminum foam as core materials with basalt fiber(BF and ultra-high molecular weight polyethylene(UHMWPE fiber composite as faceplate. The effect of factors of different fiber type faceplates, fabric layer design and the thickness of the corematerials on the impact properties and damage mode of aluminum foam sandwich structure was studied. The impact properties were also analyzed to compare with aluminum honeycomb sandwich structure. The results show that BF/aluminum foam sandwich structural composites has bigger impact damage load than UHMWPE/aluminum foam sandwich structure, but less impact displacement and energy absorption. The inter-layer hybrid fabric design of BF and UHMWPE has higher impact load and energy absorption than the overlay hybrid fabric design faceplate sandwich structure. With the increase of the thickness of aluminum foam,the impact load of the sandwich structure decreases, but the energy absorption increases. Aluminum foam sandwich structure has higher impact load than the aluminum honeycomb sandwich structure, but smaller damage energy absorption; the damage mode of aluminum foam core material is mainly the fracture at the impact area, while aluminum honeycomb core has obvious overall compression failure.

  16. Transmission loss optimization in acoustic sandwich panels

    Science.gov (United States)

    Makris, S. E.; Dym, C. L.; MacGregor Smith, J.

    1986-06-01

    Considering the sound transmission loss (TL) of a sandwich panel as the single objective, different optimization techniques are examined and a sophisticated computer program is used to find the optimum TL. Also, for one of the possible case studies such as core optimization, closed-form expressions are given between TL and the core-design variables for different sets of skins. The significance of these functional relationships lies in the fact that the panel designer can bypass the necessity of using a sophisticated software package in order to assess explicitly the dependence of the TL on core thickness and density.

  17. 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.

  18. Production of monoclonal antibodies for sandwich immunoassay detection of ciguatoxin 51-hydroxyCTX3C.

    Science.gov (United States)

    Tsumuraya, Takeshi; Fujii, Ikuo; Inoue, Masayuki; Tatami, Atsushi; Miyazaki, Keisuke; Hirama, Masahiro

    2006-09-01

    Every year, more than 50,000 people in subtropical and tropical regions suffer from ciguatera seafood poisoning. The extremely low level of the causative neurotoxins (ciguatoxins) in fish has hampered the preparation of antibodies for detection of the toxins. In this study, we produced a monoclonal antibody (8H4) against the right end of ciguatoxin CTX1B (1) and 51-hydroxyCTX3C (3) by immunizing mice with the keyhole limpet hemocyanin-conjugate of the synthetic HIJKLM ring fragment (10). We used 8H4 and another previously reported monoclonal antibody (10C9) that recognizes the left end of 3 to develop a sandwich enzyme-linked immunosorbent assay (ELISA) to detect 3. The assay could detect 3 down to the ppb level and lacked cross-reactivity with other related marine toxins, including brevetoxin A, brevetoxin B, okadaic acid, and maitotoxin.

  19. Synthesis-based approach toward direct sandwich immunoassay for ciguatoxin CTX3C.

    Science.gov (United States)

    Oguri, Hiroki; Hirama, Masahiro; Tsumuraya, Takeshi; Fujii, Ikuo; Maruyama, Megumi; Uehara, Hisatoshi; Nagumo, Yoko

    2003-06-25

    Ciguatoxins are the major causative toxins of ciguatera seafood poisoning. Limited availability of ciguatoxins has hampered the development of a reliable and specific immunoassay for detecting these toxins in contaminated fish. Monoclonal antibodies (mAbs) specific against both ends of ciguatoxin CTX3C were prepared by immunization of mice with protein conjugates of rationally designed synthetic haptens, 3 and 4, in place of the natural toxin. Haptenic groups that possess a surface area larger than 400 A(2) were required to produce mAbs that can bind strongly to CTX3C itself. A direct sandwich enzyme-linked immunosorbent assay (ELISA) using these mAbs was established to detect CTX3C at the ppb level with no cross-reactivity against other related marine toxins, including brevetoxin A, brevetoxin B, okadaic acid, or maitotoxin.

  20. 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

    Glucagon is a metabolically important hormone, but many aspects of its physiology remain obscure, because glucagon secretion is difficult to measure in mice and rats due to methodological inadequacies. Here, we introduce and validate a low-volume, enzyme-linked immunosorbent glucagon assay...... according to current analytical guidelines, including tests of sensitivity, specificity, and accuracy, and compare it, using the Bland-Altman algorithm and size-exclusion chromatography, with three other widely cited assays. After demonstrating adequate performance of the assay, we measured glucagon...... and returning to basal levels at 6 min (mice) and 12 min (rats). d-Mannitol (osmotic control) was without effect. Ketamine/xylazine anesthesia in mice strongly attenuated (P assay. In conclusion, dynamic analysis...

  1. 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.

  2. 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

  3. Plastic antibody based surface plasmon resonance nanosensors for selective atrazine detection

    Energy Technology Data Exchange (ETDEWEB)

    Yılmaz, Erkut [Department of Chemistry, Aksaray University, 68100 Aksaray (Turkey); Özgür, Erdoğan; Bereli, Nilay; Türkmen, Deniz [Department of Chemistry, Hacettepe University, 06800 Ankara (Turkey); Denizli, Adil, E-mail: denizli@hacettepe.edu.tr [Department of Chemistry, Hacettepe University, 06800 Ankara (Turkey)

    2017-04-01

    This study reports a surface plasmon resonance (SPR) based affinity sensor system with the use of molecular imprinted nanoparticles (plastic antibodies) to enhance the pesticide detection. Molecular imprinting based affinity sensor is prepared by the attachment of atrazine (chosen as model pesticide) imprinted nanoparticles onto the gold surface of SPR chip. Recognition element of the affinity sensor is polymerizable form of aspartic acid. The imprinted nanoparticles were characterized via FTIR and zeta-sizer measurements. SPR sensors are characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FTIR) and contact angle measurements. The imprinted nanoparticles showed more sensitivity to atrazine than the non-imprinted ones. Different concentrations of atrazine solutions are applied to SPR system to determine the adsorption kinetics. Langmuir adsorption model is found as the most suitable model for this affinity nanosensor system. In order to show the selectivity of the atrazine-imprinted nanoparticles, competitive adsorption of atrazine, simazine and amitrole is investigated. The results showed that the imprinted nanosensor has high selectivity and sensitivity for atrazine. - Highlights: • SPR based affinity sensor system was developed via molecular imprinting. • Recognition element of the affinity sensor is polymerizable form of an amino acid. • Combination of SPR and MIP offers highly selective sensor with long shelf-life. • Plastic antibody based biomimetic sensors offer relatively cheaper production. • Plastic antibody based biomimetic sensors offer high physical, chemical stability.

  4. Plastic antibody based surface plasmon resonance nanosensors for selective atrazine detection

    International Nuclear Information System (INIS)

    Yılmaz, Erkut; Özgür, Erdoğan; Bereli, Nilay; Türkmen, Deniz; Denizli, Adil

    2017-01-01

    This study reports a surface plasmon resonance (SPR) based affinity sensor system with the use of molecular imprinted nanoparticles (plastic antibodies) to enhance the pesticide detection. Molecular imprinting based affinity sensor is prepared by the attachment of atrazine (chosen as model pesticide) imprinted nanoparticles onto the gold surface of SPR chip. Recognition element of the affinity sensor is polymerizable form of aspartic acid. The imprinted nanoparticles were characterized via FTIR and zeta-sizer measurements. SPR sensors are characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FTIR) and contact angle measurements. The imprinted nanoparticles showed more sensitivity to atrazine than the non-imprinted ones. Different concentrations of atrazine solutions are applied to SPR system to determine the adsorption kinetics. Langmuir adsorption model is found as the most suitable model for this affinity nanosensor system. In order to show the selectivity of the atrazine-imprinted nanoparticles, competitive adsorption of atrazine, simazine and amitrole is investigated. The results showed that the imprinted nanosensor has high selectivity and sensitivity for atrazine. - Highlights: • SPR based affinity sensor system was developed via molecular imprinting. • Recognition element of the affinity sensor is polymerizable form of an amino acid. • Combination of SPR and MIP offers highly selective sensor with long shelf-life. • Plastic antibody based biomimetic sensors offer relatively cheaper production. • Plastic antibody based biomimetic sensors offer high physical, chemical stability.

  5. 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...... anti-uPAR monoclonal antibody (MAb). The detection limit of the assay is approximately 0.5 fmol/ml. A linear dose-response is obtained with up to 40 fmol/ml of uPA:uPAR complexes, while uPA and uPAR separately do not cause any response in the ELISA. A buffer which has been used previously for optimal...... 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...

  6. Estimation of serum thyroglobulin using isotopic and non-isotopic methods: a comparison between RIA, IRMA and ELISA

    International Nuclear Information System (INIS)

    Ajay Kumar; Velumani, A.; Dandekar, S.R.; Shah, D.H.; Rajashekharrao, B.

    1997-01-01

    Three in-house immunoassays viz, RIA, IRMA and ELISA for estimation of serum Tg were compared for their assay characteristics and clinical utility. The inter- and intra-assay coefficient of variations of RIA and IRMA were comparable and were marginally better than that of ELISA. The sensitivity of IRMA was superior to RIA which in turn was superior than ELISA. Incubation time for both IRMA and ELISA was 4 h as compared to 90 h required for RIA. The enzyme conjugated antibody had longest shelf-life (9 months) followed by radiolabeled antibody (3 months) while radiolabeled Tg had shortest shelf-life (3 weeks). There was no interference from circulating anti-Tg autoantibodies in the RIA of Tg as compared to a gross underestimation observed in both sandwich methods. Assays correlated well with each other (r > 0.85, n=200) and had suitable clinical utility (sensitivity > 93% and specificity > 89%). Each assay though had its own merits and demerits, yet it served the clinical utility for an effective management of patients with differentiated thyroid carcinoma. (author)

  7. Testing of the scintillation sandwich prototype

    International Nuclear Information System (INIS)

    Vashkevich, V.

    1995-06-01

    The 3 m 2 prototype of the surface detector using optical fiber readout was completely prepared for testing measurements in February 1995 at Fermilab. Two 25 mm thick, 3 m 2 acrylic scintillation plates (1.2 x 2.5 m 2 ) are used for light collection in the upper (above the 25 mm steel plate) and lower (below the steel) counters of the sandwich. The light is collected with the help of 1 mm diameter wavelength shifter fiber loops 3 m long inserted in the grooves on the top surface of the scintillator, 3 fibers per groove. We used Kurary Y11, 200 ppm of shifter dye, and double clad fibers. 1.5 m of clear fibers spliced to each end of the shifter fiber transport the light to the phototube. Spacing between the grooves is 5 cm. The counter's edges were painted with BICRON (BC620) white reflective paint. The scintillation plates were wrapped with Dupont Tyvek. The glued bundle of fibers is connected to an EMI-9902KB 38 mm phototube through the simple light mixer bar. Used PM has a ''green extended'' rubidium bialkali photocathode. The report contains information on the testing of the scintillation sandwich

  8. 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...

  9. Development of ELISA kit for rat albumin

    International Nuclear Information System (INIS)

    Yuan Zhigang; Han Shiquan; Liu Yibing; Xu Wenge; Jia Juanjuan

    2009-01-01

    The Anti-rat albumin serum was prepared by immunized the sheep with rat albumin. A ELISA method was established for rat albumin. The measurement range of the assay was 1-50 mg/L, sensitivity of the assay was 0.42 mg/L, recovery rate was 85.0%-106.0%. Intra-and inter-assay variation coefficients were <8.9% and <12.8% respectively. The correlation coefficients between measured and expected values were 0.999 after serial dilution of the urine samples with high concentrations of rat albumin. A good correlation was observed between the ELISA and RIA methods, and the kit for rat albumin might provide a convenience in exploitation of renal drugs and experimental injury of the kidney. (authors)

  10. Evaluation of a newly designed sandwich enzyme linked immunosorbent assay for the detection of hydatid antigen in serum, urine and cyst fluid for diagnosis of cystic echinococcosis.

    Science.gov (United States)

    Chaya, Dr; Parija, Subhash Chandra

    2013-07-01

    Cystic echinococcosis (CE) is a zoonotic disease of humans with variable clinical manifestations. Imaging and immunological methods are currently the mainstay of diagnosis of this disease. Although the immunological tests for detection of anti-echinococcal antibodies have several disadvantages, they are widely being used. Antigen is far more superior than antibody detection test as they can provide a specific parasitic diagnosis. A sandwich enzyme linked immunosorbent assay (ELISA) was designed using antibodies to 24 kDa urinary hydatid antigen for the detection of hydatid antigens in urine, serum and cyst fluid specimens. The performance of this novel test was compared with that of other hydatid antibody detection ELISA and enzyme immune transfer blot (EITB) using radiological and surgical confirmation as the gold standard. The antigen detection ELISA showed 100% sensitivity and specificity when tested with cyst fluid. On testing urine and serum, the antigen detection ELISA was found to be more specific than antibody detection ELISA. EITB was found to be the most sensitive and specific test. ELISA using polyclonal antibodies against 24 kDa urinary hydatid protein was moderately sensitive to detect hydatid antigen in serum and urine. Hence polyclonal antibodies to 24 kDa urinary hydatid antigen can be used as an alternative source of antibody to detect hydatid antigen in serum, urine and cyst fluid. In the present study, EITB was found to be highly specific test for detection of hydatid antibodiesin serum. 24 kDa protein was found to be specific and of diagnostic value in CE.

  11. 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 loa...

  12. The sandwich sign | Mahomed | SA Journal of Radiology

    African Journals Online (AJOL)

    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 ...

  13. Measuring Cohesive Laws for Interfaces in Sandwich Structures

    DEFF Research Database (Denmark)

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

    2006-01-01

    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...

  14. 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...... for the chosen geometries and mixed mode loading conditions....

  15. 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

    The present work investigates the possibilities and drawbacks when applying sandwich as opposed to single skin composites in the flanges of the load carrying spar in a future 180 m wind turbine rotor. FEA is applied to investigate two basic designs with single skin and sandwich flanges respectively...

  16. 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...

  17. ELISA technique standardisation for human toxocariasis diagnosis

    International Nuclear Information System (INIS)

    Espinoza, Y.; Suarez, R.; Huiza, A.

    2003-01-01

    To standardise ELISA technique for toxocara canis human infection diagnosis by using excreted-secreted antigen prepared in our country. T. canis eggs were collected by incubation with formalin (2%) at 28 o C in order to obtain third stage larvae that were freed and incubated in RPMI at 37 o C for 7 days; the medium was replaced by a similar one and stored at -20 o C. Antigen was concentrated and protein dosage was made. Sera from patients with toxocariasis and newborns were used as positive and negative controls by ELISA technique, dilutions 1/4 to 1/1024. Polystyrene plates were sensitised with antigen in several concentrations and conjugated peroxidase with horseradish IgG, anti human IgG and substrate OPD were used. Absorbance was read with spectrophotometer (Multiskan plus labsystems) at 492 nm. Cut off point was determined by negative sera absorbencies arithmetic mean plus 3 standard deviations. Antigen concentration was 50 ug/mL, sera dilution 1/128, conjugate dilution 1/1000 with optical density above 0,241. ELISA technique for serologic diagnosis of human infection by toxocara canis could be used in epidemiological studies in our country. Its efficacy will be determined in future studies

  18. Development of monoclonal antibody-based immunoassays for the analysis of bisphenol A in canned vegetables.

    Science.gov (United States)

    Moreno, María J; D'Arienzo, Pasquale; Manclús, Juan J; Montoya, Angel

    2011-01-01

    The aim of this work was the development of monoclonal antibodies (MAbs) and highly sensitive immunoassays (ELISAs) to bisphenol A (BPA), a well-known endocrine disruptor able to migrate from the internal coating of cans to food contained inside, particularly vegetables. To produce MAbs to BPA, four synthetic compounds were conjugated to proteins and used as immunizing haptens in mice. By applying hybridoma technology, several MAbs were produced and selected. These antibodies were characterized in the conjugate-coated and in the antibody-coated formats, using both homologous and heterologous conjugates. Three indirect ELISA based on the MAbs showing the highest affinity to BPA were selected. The limit of detection of the most sensitive ELISA was 0.22 nM (0.05 ng/mL), with an I₅₀ value of around 1 nM (0.23 ng/mL). An homologous ELISA based on the MAb BPAB-11 was applied to the simple, direct determination of BPA in the liquid portion of canned artichoke, peas, and sweet corn. Only sample dilution in an appropriate saline buffer was required to minimize matrix effects and to enter the ELISA working range. Recovery and precision of the method were evaluated by spiking the liquid portion of these cans with BPA at 20, 50, and 100 ng/mL. Coefficients of variation were below 20% in most cases. With regard to recovery, the analytical data obtained were also acceptable. This immunoassay has therefore proved its potential as a new tool for the rapid, sensitive and accurate determination of BPA in canned food.

  19. Impact damage in aircraft composite sandwich panels

    Science.gov (United States)

    Mordasky, Matthew D.

    An experimental study was conducted to develop an improved understanding of the damage caused by runway debris and environmental threats on aircraft structures. The velocities of impacts for stationary aircraft and aircraft under landing and takeoff speeds was investigated. The impact damage by concrete, asphalt, aluminum, hail and rubber sphere projectiles was explored in detail. Additionally, a kinetic energy and momentum experimental study was performed to look at the nature of the impacts in more detail. A method for recording the contact force history of the impact by an instrumented projectile was developed and tested. The sandwich composite investigated was an IM7-8552 unidirectional prepreg adhered to a NOMEXRTM core with an FM300K film adhesive. Impact experiments were conducted with a gas gun built in-house specifically for delivering projectiles to a sandwich composite target in this specic velocity regime (10--140 m/s). The effect on the impact damage by the projectile was investigated by ultrasonic C-scan, high speed camera and scanning electron and optical microscopy. Ultrasonic C-scans revealed the full extent of damage caused by each projectile, while the high speed camera enabled precise projectile velocity measurements that were used for striking velocity, kinetic energy and momentum analyses. Scanning electron and optical images revealed specific features of the panel failure and manufacturing artifacts within the lamina and honeycomb core. The damage of the panels by different projectiles was found to have a similar damage area for equivalent energy levels, except for rubber which had a damage area that increased greatly with striking velocity. Further investigation was taken by kinetic energy and momentum based comparisons of 19 mm diameter stainless steel sphere projectiles in order to examine the dominating damage mechanisms. The sandwich targets were struck by acrylic, aluminum, alumina, stainless steel and tungsten carbide spheres of the

  20. 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.

  1. 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.

  2. 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.

  3. A sandwich HIV p24 amperometric immunosensor based on a direct gold electroplating-modified electrode.

    Science.gov (United States)

    Zheng, Lei; Jia, Liyong; Li, Bo; Situ, Bo; Liu, Qinlan; Wang, Qian; Gan, Ning

    2012-05-18

    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.

  4. 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.

  5. Optimizing complement-activating antibody-based cancer immunotherapy: a feasible strategy?

    Directory of Open Access Journals (Sweden)

    Maio Michele

    2004-06-01

    Full Text Available Abstract Passive immunotherapy with monoclonal antibodies (mAb targeted to specific tumor-associated antigens is amongst the most rapidly expanding approaches to biological therapy of cancer. However, until now a limited number of therapeutic mAb has demonstrated clinical efficacy in selected neoplasia. Results emerging from basic research point to a deeper characterization of specific biological features of neoplastic cells as crucial to optimize the clinical potential of therapeutic mAb, and to identify cancer patients who represent the best candidates to antibody-based immunotherapy. Focus on the tissue distribution and on the functional role of membrane complement-regulatory proteins such as Protectin (CD59, which under physiologic conditions protects tissues from Complement (C-damage, might help to optimize the efficacy of immunotherapeutic strategies based on C-activating mAb.

  6. Antibody-Based Agents in the Management of Antibiotic-Resistant Staphylococcus aureus Diseases

    Science.gov (United States)

    Speziale, Pietro; Rindi, Simonetta

    2018-01-01

    Staphylococcus aureus is a human pathogen that can cause a wide spectrum of diseases, including sepsis, pneumonia, arthritis, and endocarditis. Ineffective treatment of a number of staphylococcal infections with antibiotics is due to the development and spread of antibiotic-resistant strains following decades of antibiotic usage. This has generated renewed interest within the scientific community in alternative therapeutic agents, such as anti-S. aureus antibodies. Although the role of antibodies in the management of S. aureus diseases is controversial, the success of this pathogen in neutralizing humoral immunity clearly indicates that antibodies offer the host extensive protection. In this review, we report an update on efforts to develop antibody-based agents, particularly monoclonal antibodies, and their therapeutic potential in the passive immunization approach to the treatment and prevention of S. aureus infections. PMID:29533985

  7. Assessment of Antibody-based Drugs Effects on Murine Bone Marrow and Peritoneal Macrophage Activation.

    Science.gov (United States)

    Kozicky, Lisa; Sly, Laura M

    2017-12-26

    Macrophages are phagocytic innate immune cells, which initiate immune responses to pathogens and contribute to healing and tissue restitution. Macrophages are equally important in turning off inflammatory responses. We have shown that macrophages stimulated with intravenous immunoglobulin (IVIg) can produce high amounts of the anti-inflammatory cytokine, interleukin 10 (IL-10), and low levels of pro-inflammatory cytokines in response to bacterial lipopolysaccharides (LPS). IVIg is a polyvalent antibody, primarily immunoglobulin Gs (IgGs), pooled from the plasma of more than 1,000 blood donors. It is used to supplement antibodies in patients with immune deficiencies or to suppress immune responses in patients with autoimmune or inflammatory conditions. Infliximab, a therapeutic anti-tumor necrosis factor alpha (TNFα) antibody, has also been shown to activate macrophages to produce IL-10 in response to inflammatory stimuli. IVIg and other antibody-based biologics can be tested to determine their effects on macrophage activation. This paper describes methods for derivation, stimulation, and assessment of murine bone marrow macrophages activated by antibodies in vitro and murine peritoneal macrophages activated with antibodies in vivo. Finally, we demonstrate the use of western blotting to determine the contribution of specific cell signaling pathways to anti-inflammatory macrophage activity. These protocols can be used with genetically modified mice, to determine the effect of a specific protein(s) on anti-inflammatory macrophage activation. These techniques can also be used to assess whether specific biologics may act by changing macrophages to an IL-10-producing anti-inflammatory activation state that reduces inflammatory responses in vivo. This can provide information on the role of macrophage activation in the efficacy of biologics during disease models in mice, and provide insight into a potential new mechanism of action in people. Conversely, this may caution

  8. 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

    2018-03-01

    This study investigated beta-casomorphin 7 (BCM7) in yogurt by means of LC-tandem MS (MS/MS) and enzyme-linked immunosorbent 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.

  9. Selection of specific inhibitor peptides in enzyme-linked immunosorbent assay (ELISA) of cardiac troponin I using immuno-dominant epitopes as competitor.

    Science.gov (United States)

    Rezaee, Majid Asiabanha; Rasaee, Mohammad Javad; Mohammadnejad, Javad

    2017-01-01

    Human cardiac troponin I (cTni) is the gold marker for early diagnosis of myocardial infarction. In this regard, four immune-dominant epitopes of cTni were predicted and their 3D structures were determined. Thereafter, the competitive performance of the peptides was monitored with the developed polyclonal antibody-based indirect competitive ELISA; a half-maximal inhibitory concentration (IC50) of 0.49 (µg/mL) and detection limit of 0.037 (µg/mL) were achieved for recombinant cTni. The competitive ELISA determined sensitivity levels of 0.306, 0.141, 0.960, and 0.155 (µg/mL), respectively, for each peptide as competitor. We indicated that two of the selected epitopes have significant sensitivity scales and inhibition ability.

  10. 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...... monolithic structures of the same weight. The vast range of applications of such materials includes wind turbines, marine, and aerospace industries. In this work, geometrically nonlinear finite element analysis is conducted to investigate the fracture parameters and debond propagation of sandwich columns...

  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. ELISA technique standardization for strongyloidiasis diagnosis

    International Nuclear Information System (INIS)

    Huapaya, P.; Espinoza, I.; Huiza, A.; Universidad Nacional Mayor de San Marcos, Lima; Sevilla, C.

    2002-01-01

    To standardize ELISA technique for human Strongyloides stercoralis infection diagnosis a crude antigen was prepared using filariform larvae obtained from positive stool samples cultured with charcoal. Harvested larvae were crushed by sonication and washed by centrifugation in order to obtain protein extracts to be used as antigen. Final protein concentration was 600 μg/mL. Several kinds of ELISA plates were tested and antigen concentration, sera dilution, conjugate dilution and cut off were determined to identify infection. Sera from patients with both hyper-infection syndrome and intestinal infection demonstrated by parasitological examination were positive controls and sera from people living in non-endemic areas with no infection demonstrated by parasitological examination were negative controls. Best values were 5 μg/mL for antigen, 1/64 for sera, 1/1000 for conjugate; optical density values for positive samples were 1,2746 (1,1065 - 1,4206, DS = 0,3284) and for negative samples 0,4457 (0,3324 - 0,5538, DS = 0,2230). Twenty sera samples from positive subjects and one hundred from negative subjects were examined, obtaining 90% sensitivity and 88% specificity. The results show this technique could be useful as strongyloidiasis screening test in population studies

  13. 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.

  14. Expression, purification of metallothionein genes from freshwater crab (Sinopotamon yangtsekiense) and development of an anti-metallothionein ELISA

    Science.gov (United States)

    Zhang, Hao; Zhou, Hui

    2017-01-01

    Using the phoA-fusion technology, the recombinant metallothionein (MT) from freshwater crab (Sinopotamon yangtsekiense) has been successfully produced in Escherichia coli. MT purified from the bacterial suspension showed one polypeptide with a molecular weight of 7 kDa by tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Tricine-SDS-PAGE). Western-blotting confirmed the polypeptides had a specific reactivity with mouse polyclonal MT anti-serum. Based on the purified MT and MT anti-serum, the reaction parameters for an enzyme-linked immunosorbent assay (ELISA) were developed. The direct coating ELISA showed a higher linear relationship compared to antibody sandwich coating ELISA. The optimal dilution rates of purified MT anti-serum and coating period were shown to be 1:160,000 and 12 hours at 4°C. At 37°C, the appropriate reaction duration of the first antibody and the second antibody were 2 hours and 1 hour, respectively. According to these optimal parameters, the standard linear equation, y = 0.0032x + 0.1769 (R2 = 0.9779, x, y representing MT concentration and OD450 value), was established for the determination of MT concentration with a valid range of 3.9–500 ng/ml. In verification experiments, the mean coefficients of variation of the intra-assay and inter-assay were 3.260% and 3.736%, respectively. According to the result of MT recovery, ELISA with an approaching 100% MT recovery was more reliable and sensitive than the Cd saturation assay. In conclusion, the newly developed ELISA of this study was precise, stable and repeatable, and could be used as a biomarker tool to monitor pollution by heavy metals. PMID:28350826

  15. [Effect evaluation of three ELISA kits in detection of fasciolasis].

    Science.gov (United States)

    Ai, Lin; Chen, Mu-Xin; Chen, Shao-Hong; Chu, Yan-Hong; Cai, Yu-Chun; Zhou, Xiao-Nong; Chen, Jia-Xu

    2013-04-01

    To evaluate the effect of 3 ELISA kits on detection of human fasciolasis. Twenty-six serum samples from patients with fasciolasis, 180 serum samples from patients with other parasitic diseases as well as 26 serum samples from healthy people were detected by ELISA kits which using soluble antigen of Fasciola gigantica, Fasciola hepatica (Fg-ELISA and Fh-ELISA) as well as IgG antigen ELISA detection kits made by DRG company in Germany. The effects of the 3 kits were evaluated. The sensitivities of Fg-ELISA, Fh-ELISA, and DRG-ELISA were 100.0%, 80.8% (95% CI: 65.7%-95.9%) and 100.0%, respectively; the specificities of the three were 87.9% (95% CI: 83.5%-92.4%), 85.0%(95% CI: 80.1%-89.9%) and 83.5% (95% CI: 78.4%-88.6%), respectively, and Youden indexes of them were 0.88, 0.66 and 0.84, respectively. The detection rate of Fg-ELISA (100%) was significantly higher than that of Fh-ELISA (80.8%) (P DRG-ELISA for clinical sample tests as well as massive screening in fasciolasis endemic areas in southwest China.

  16. Validation of an enzyme-linked immunosorbent assay (ELISA) for the measurement of canine S100A12.

    Science.gov (United States)

    Heilmann, Romy M; Cranford, Shannon M; Ambrus, Andy; Grützner, Niels; Schellenberg, Stefan; Ruaux, Craig G; Suchodolski, Jan S; Steiner, Jörg M

    2016-03-01

    Canine S100 calcium-binding protein A12 (cS100A12) shows promise as biomarker of inflammation in dogs. A previously developed cS100A12-radioimmunoassay (RIA) requires radioactive tracers and is not sensitive enough for fecal cS100A12 concentrations in 79% of tested healthy dogs. An ELISA assay may be more sensitive than RIA and does not require radioactive tracers. The purpose of the study was to establish a sandwich ELISA for serum and fecal cS100A12, and to establish reference intervals (RI) for normal healthy canine serum and feces. Polyclonal rabbit anti-cS100A12 antibodies were generated and tested by Western blotting and immunohistochemistry. A sandwich ELISA was developed and validated, including accuracy and precision, and agreement with cS100A12-RIA. The RI, stability, and biologic variation in fecal cS100A12, and the effect of corticosteroids on serum cS100A12 were evaluated. Lower detection limits were 5 μg/L (serum) and 1 ng/g (fecal), respectively. Intra- and inter-assay coefficients of variation were ≤ 4.4% and ≤ 10.9%, respectively. Observed-to-expected ratios for linearity and spiking recovery were 98.2 ± 9.8% (mean ± SD) and 93.0 ± 6.1%, respectively. There was a significant bias between the ELISA and the RIA. The RI was 49-320 μg/L for serum and 2-484 ng/g for fecal cS100A12. Fecal cS100A12 was stable for 7 days at 23, 4, -20, and -80°C; biologic variation was negligible but variation within one fecal sample was significant. Corticosteroid treatment had no clinically significant effect on serum cS100A12 concentrations. The cS100A12-ELISA is a precise and accurate assay for serum and fecal cS100A12 in dogs. © 2016 American Society for Veterinary Clinical Pathology.

  17. Iodoacetyl-functionalized pullulan: A supplemental enhancer for single-domain antibody-polyclonal antibody sandwich enzyme-linked immunosorbent assay for detection of survivin.

    Science.gov (United States)

    Matsushita, Takahiko; Arai, Hidenao; Koyama, Tetsuo; Hatano, Ken; Nemoto, Naoto; Matsuoka, Koji

    2017-11-01

    Survivin, an inhibitor of the apoptosis protein family, is a potent tumor marker for diagnosis and prognosis. The enzyme-linked immunosorbent assay (ELISA) is one of the methods that has been used for detection of survivin. However, ELISA has several disadvantages caused by the use of conventional antibodies, and we have therefore been trying to develop a novel ELISA system using camelid single-domain antibodies (VHHs) as advantageous replacements. Here we report a supplemental approach to improve the VHH-polyclonal antibody sandwich ELISA for survivin detection. Iodoacetyl-functionalized pullulan was synthesized, and its thiol reactivity was characterized by a model reaction with l-cysteine. The thiophilic pullulan was applied to an immunoassay asan additive upon coating of standard assay plates with an anti-survivin VHH fusion protein with C-terminal cysteine. The results showed that the mole ratio of the additive to VHH had a significant effect on the consequent response. Mole ratios of 0.07, 0.7, and 7 led to 90% lower, 15% higher, and 69% lower responses, respectively, than the response of a positive control in which no additive was used. The background levels observed in any additive conditions were as low as that of a negative control lacking both VHH and the additive. These results indicate the applicability of the thiol-reactive pullulan as a response enhancer to VHH-based ELISA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 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

  19. Smart FRP Composite Sandwich Bridge Decks in Cold Regions

    Science.gov (United States)

    2011-07-01

    In this study, new and integrated Smart honeycomb Fiber-Reinforced Polymer (S-FRP) : sandwich materials for various transportation construction applications, with particular emphasis : on highway bridge decks in cold regions, were developed and teste...

  20. A new ELISA for the quantification of equine procalcitonin in plasma as potential inflammation biomarker in horses.

    Science.gov (United States)

    Rieger, Martin; Kochleus, Christian; Teschner, Dana; Rascher, Daniela; Barton, Ann Kristin; Geerlof, Arie; Kremmer, Elisabeth; Schmid, Michael; Hartmann, Anton; Gehlen, Heidrun

    2014-09-01

    In human medicine, procalcitonin (PCT) is a very common and well-established biomarker for sepsis. Even though sepsis is also a leading cause of death in foals and adult horses, up to now, no data about the role of equine PCT in septic horses has been available. Based on monoclonal antibodies targeted against human PCT, we report here the development of a sandwich ELISA for the quantification of equine PCT in equine plasma samples. The ELISA was characterized for intra- and interassay variance and a working range from 25 to 1,000 ng mL(-1) was defined as within this range; both intra- and interassay variances were below 15 %. The target recovery ranged between 73 and 106 %. The ELISA was used to determine the equine PCT concentration in 24 healthy and 5 septic horses to show the potential for clinical evaluation of equine PCT. Significantly different (P = 0.0006) mean equine PCT concentrations were found for the healthy control group and the sepsis group (47 and 8,450 ng mL(-1)).

  1. 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....... The transition points where the crack kinks are identified and the influence of four various interface design modifications on the propagation path and fracture resistance are investigated....

  2. Mycotoxin determination using RIA and ELISA methods

    Energy Technology Data Exchange (ETDEWEB)

    Fukal, L; Sova, Z

    1985-12-01

    Experience is summed up of various authors with the determination of some mycotoxins (aflatoxin, ochratoxin A, T-2 toxin, rubratoxin, zearalenon, sterigmatocystine) using radioimmunoassay and enzyme immunoassay. For RIA purposes, tritium or sometimes iodine 125 is frequently used for labelling mycotoxins. Mycotoxins do not show immunogenic properties and must thus be conjugated with a high-molecular compound (serum albumin, polylysine) prior to immunozation. Factors are discussed making mycotoxin determination in foods difficult. Specificity of the obtained antisera is total between the individual mycotoxin groups while cross reactions are always recorded within the groups. RIA makes it possible to determine down to 200 pg (labelled with /sup 3/H) or 5 pg (labelled with /sup 125/I) of mycotoxins in a standard solution. In addition to high sensitivity and specificity, immunoassays of mycotoxins minimize the quantities of samples and solvents needed for extraction. Large series of samples can be processed using automatic analyzers. ELISA generally is more advantageous than RIA.

  3. 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.).

  4. Dynamic Response of Functionally Graded Carbon Nanotube Reinforced Sandwich Plate

    Science.gov (United States)

    Mehar, Kulmani; Panda, Subrata Kumar

    2018-03-01

    In this article, the dynamic response of the carbon nanotube-reinforced functionally graded sandwich composite plate has been studied numerically with the help of finite element method. The face sheets of the sandwich composite plate are made of carbon nanotube- reinforced composite for two different grading patterns whereas the core phase is taken as isotropic material. The final properties of the structure are calculated using the rule of mixture. The geometrical model of the sandwich plate is developed and discretized suitably with the help of available shell element in ANSYS library. Subsequently, the corresponding numerical dynamic responses computed via batch input technique (parametric design language code in ANSYS) of ANSYS including Newmark’s integration scheme. The stability of the sandwich structural numerical model is established through the proper convergence study. Further, the reliability of the sandwich model is checked by comparison study between present and available results from references. As a final point, some numerical problems have been solved to examine the effect of different design constraints (carbon nanotube distribution pattern, core to face thickness ratio, volume fractions of the nanotube, length to thickness ratio, aspect ratio and constraints at edges) on the time-responses of sandwich plate.

  5. Effect of nanomodified polyester resin on hybrid sandwich laminates

    International Nuclear Information System (INIS)

    Anbusagar, NRR.; Giridharan, P.K.; Palanikumar, K.

    2014-01-01

    Highlights: • Effect of nanomodified polyester resin on hybrid sandwich laminates is evaluated. • The hybrid sandwich laminates are fabricated with varying wt% of nanoclay. • Flexural, impact and moisture absorbtion properties are evaluated for hybrid composites. • Scanning electron microscopy is utilized to analyze the dispersion of clay and fractured surfaces of the nanocomposites. - Abstract: Effect of nanoclay modified polyester resin on flexural, impact, hardness and water absorption properties of untreated woven jute and glass fabric hybrid sandwich laminates have been investigated experimentally. The hybrid sandwich laminates are prepared by hand lay-up manufacturing technique (HL) for investigation. All hybrid sandwich laminates are fabricated with a total of 10 layers, by varying the extreme layers and wt% of nanoclay in polyester resin so as to obtain four different combinations of hybrid sandwich laminates. For comparison of the composite with hybrid composite, jute fiber reinforced composite laminate also fabricated. X-ray diffraction (XRD) results obtained from samples with nanoclay indicated that intergallery spacing of the layered clay increases with matrix. Scanning electron microscopy (SEM) gave a morphological picture of the cross-sections and energy dispersive X-ray spectroscopy (EDS) allowed investigating the elemental composition of matrix in composites. The testing results indicated that the flexural properties are greatly increased at 4% of nanoclay loading while impact, hardness and water absorption properties are increased at 6% of nanoclay loading. A plausible explanation for high increase of properties has also been discussed

  6. Added value of antigen ELISA in the diagnosis of neurocysticercosis in resource poor settings.

    Directory of Open Access Journals (Sweden)

    Sarah Gabriël

    Full Text Available BACKGROUND: Neurocysticercosis (NCC is the most common cause of acquired epilepsy in Taenia solium endemic areas, primarily situated in low-income countries. Diagnosis is largely based upon the "Del Brutto diagnostic criteria" using the definitive/probable/no NCC diagnosis approach. Neuroimaging and specific T. solium cysticercosis antibody detection results are at the mainstay of this diagnosis, while antigen detection in serum has never been included. This study aimed at evaluating the addition of antigen detection as a major diagnostic criterion, especially in areas where neuroimaging is absent. METHODS: The B158/B60 monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA for the detection of circulating cysticercus antigen was carried out retrospectively on serum samples collected during a hospital-based study from 83 people with epilepsy (PWE in an endemic area. RESULTS: The addition of antigen results as a major criterion allowed the correct diagnosis of definitive NCC in 10 out of 17 patients as opposed to 0/17 without antigen results in the absence of neuroimaging. A sensitivity of 100% and a specificity of 84% were determined for the diagnosis of active NCC using antigen ELISA. While the use of a higher cutoff improves the specificity of the test to 96%, it decreases its sensitivity to 83%. CONCLUSIONS: In areas where neuroimaging is absent, NCC diagnosis according to the existing criteria is problematic. Taking into account its limitations for diagnosis of inactive NCC, antigen detection can be of added value for diagnosing NCC in PWE by supporting diagnostic and treatment decisions. Therefore, we recommend a revision of the "Del Brutto diagnostic criteria" for use in resource poor areas and suggest the inclusion of serum antigen detection as a major criterion.

  7. New monoclonal antibody-based test for Helicobacter pylori urease in gastric tissue.

    Science.gov (United States)

    Kim, Do Hyun; Kim, Ho Dong; Park, Hyeuk; Choi, Seung; Beom, Jae Won; Kim, Woo Jong; Park, Chang Kook; Lee, Young Jik; Park, Ju Young; Kim, Hyung Rag; Park, Chul; Joo, Young Eun; Jung, Young Do

    2016-01-01

    To evaluate a new monoclonal antibody for Helicobacter pylori urease in gastric tissue. A total of 107 volunteers were enrolled. All subjects underwent a (13)C-urea breath test and esophagogastroduodenoscopy. Gastric aspirates were analyzed for pH and ammonia. Six biopsy specimens in the gastric antrum and body were obtained for a rapid urease test and histology. The new monoclonal antibody-based H. pylori urease test (HPU) was performed to rapidly and qualitatively detect urease in two biopsy specimens. H. pylori infection was diagnosed in 73 subjects. The sensitivity and specificity of the HPU was 89% and 74%, respectively. The subjects were divided into two groups: one with true-positive and true-negative HPU results (n = 90) and the other with false-positive and false-negative HPU results (n = 17). Across all subjects, ammonia levels were 900.5 ± 646.7 and 604.3 ± 594.3 μmol/L (p > 0.05), and pH was 3.37 ± 1.64 and 2.82 ± 1.51 (p > 0.05). Sensitivity was higher in the presence of atrophic gastritis or intestinal metaplasia. HPU detected H. pylori in approximately 10 min. Gastric aspirate ammonia and pH levels did not affect the test results. Sensitivity was good in the presence of atrophic gastritis or intestinal metaplasia.

  8. Development of enzyme-linked immunosorbent assay (ELISA) for glutathione S-transferase (GST-S) protein in the intertidal copepod Tigriopus japonicus and its application for environmental monitoring.

    Science.gov (United States)

    Rhee, Jae-Sung; Kim, Bo-Mi; Jeong, Chang-Bum; Leung, Kenneth Mei Yee; Park, Gyung Soo; Lee, Jae-Seong

    2013-11-01

    To utilize the GST-S protein as a useful biomarker for environmental contamination, we developed a polyclonal antibody-based enzyme-linked immunosorbent assay (ELISA) in the intertidal copepod Tigriopus japonicus. Two polyclonal antibodies, TJ-GST-S1 and TJ-GST-S2, were raised against two TJ-GST-S synthetic peptides. Also a recombinant TJ-GST-S protein was purified as a standard for ELISA development. Each polyclonal antibody was tested by Western blot analysis and indirect ELISA. Of two polyclonal antibodies, TJ-GST-S2 ELISA was further employed due to its wide range of detection and the limit of specificity compared to those of TJ-GST-S1 ELISA system. After exposure to 4 metals (Ag, As, Cd, and Cu) to T. japonicus, the amount of TJ-GST-S protein was significantly elevated in a concentration-dependent manner. Also, TJ-GST-S protein was upregulated at relative high concentrations of B[α]P, PCB, and TBT. In this paper, we suggest that T. japonicas ELISA for TJ-GST-S2 is useful as a potential indicator system for marine contaminants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  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. LISA Pathfinder and eLISA news

    Science.gov (United States)

    Thorpe, James Ira; Mueller, Guido

    2014-01-01

    Two important gatherings of the space-based gravitational-wave detector community were held in Zurich, Switzerland this past March. The first was a meeting of the Science Working Team for LISA Pathfinder (LPF), a dedicated technology demonstrator mission for a future LISA-like gravitational wave observatory. LPF is entering an extremely exciting phase with launch less than 15 months away. All flight components for both the European science payload, known as the LISA Technology Package (LTP), and the NASA science payload, known as the Space Technology 7 Disturbance Reduction System (ST7-DRS), have been delivered and are undergoing integration. The final flight component for the spacecraft bus, a cold-gas thruster based on the successful GAIA design, will be delivered later this year. Current focus is on completing integration of the science payload (see Figures 1 and 2) and preparation for operations and data analysis. After a launch in Summer 2015, LPF will take approximately 90 days to reach its operational orbit around the Earth-Sun Lagrange point (L1), where it will begin science operations. After 90 days of LTP operations followed by 90 days of DRS operations, LPF will have completed its prime mission of paving the way for a space-based observatory of gravitational waves in the milliHertz band. Immediately following the meeting of the LPF team, the eLISA consortium held its third progress meeting. The consortium (www.elisascience.org) is the organizing body of the European space-based gravitational-wave community, and it was responsible for the "The Gravitational Universe" whitepaper that resulted in the November 2013 election of a gravitational-wave science theme for ESA's Cosmic Visions L3 opportunity. In preparation for an L3 mission concept call, which is expected later this decade, and for launch in the mid 2030s, the eLISA consortium members are coordinating technology development and mission study activities which will build on the LPF results. The final

  11. A chromogranin A ELISA absent of an apparent high-dose hook effect observed in other chromogranin A ELISAs.

    Science.gov (United States)

    Erickson, J Alan; Grenache, David G

    2016-01-15

    Routine testing for chromogranin A (CgA) using an established commercial ELISA revealed an apparent high-dose hook effect in approximately 15% of specimens. Investigations found the same effect in two additional ELISAs. We hypothesized that a CgA derived peptide(s) at high concentrations was responsible but experiments were inconclusive. Here we describe the analytical performance characteristics of the Chromoa™ CgA ELISA that did not display the apparent high-dose hook effect. Performance characteristics of the Chromoa ELISA were assessed. The reference interval was established utilizing healthy volunteers. Specimens producing the apparent high-dose hook effect in other assays were evaluated using the Chromoa ELISA. The limit of detection was 8ng/ml. Linearity was acceptable (slope=1.04, intercept=18.1 and r(2)=0.997). CVs were ≤4.6 and ≤9.3% for repeatability and within-laboratory imprecision, respectively. CgA was stable at ambient and refrigerated temperatures for a minimum of two and 14days, respectively. An upper reference interval limit of 95ng/ml was established. Specimens demonstrating the apparent high-dose hook effect in other ELISAs did not exhibit the phenomenon using the Chromoa ELISA. The Chromoa ELISA demonstrates acceptable performance for quantifying serum CgA. The apparent high-dose hook effect exhibited in other ELISAs was absent using the Chromoa assay. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Detection of potato mop-top virus in soils and potato tubers using bait-plant bioassay, ELISA and RT-PCR.

    Science.gov (United States)

    Arif, Muhammad; Ali, Murad; Rehman, Anayatur; Fahim, Muhammad

    2014-01-01

    The hilly region of Northwest of Pakistan is leading seed potato producing areas of the country. Soil and plant samples were collected from the region and tested for PMTV using both conventional and molecular techniques. The bait plants exhibited PMTV-characteristic v-shaped yellow leaf markings in Nicotiana debneyi plants grown in putative viruliferious soils from 20/26 locations. The results were confirmed by back inoculation of sap from both roots and leaves of bait plant on indicator hosts (N. debneyi, Nicotiana benthamiana). The root samples of bait plants grown in soils of 25 locations and leaves of 24 locations reproduced systemic infection on indicator hosts upon back inoculation. The virus was identified in bait plants grown in soils from 25/26 locations using double antibody sandwich-enzyme linked immunosorbent assay (DAS)-ELISA and reverse transcription and polymerase chain reaction (RT-PCR) methods. The products of the 566bp were amplified from coat protein region of PMTV RNA 3 in both root and leaf samples of baited plants. The virus was detected in 10 potato cultivars commercially grown in the region using DAS-ELISA and RT-PCR. The virus was also detected in zoospores of Spongospora subterranea derived from the peels of selected scabby tubers using triple antibody sandwich (TAS)-ELISA. The results indicate that a bait plant bioassay, infectivity assay, ELISA and RT-PCR can detect PMTV in roots and leaves of baited plants, field samples, zoospores of S. subterranea and tubers of 10 potato cultivars commercially grown in the region. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Characterization of sandwich panels for indentation and impact

    International Nuclear Information System (INIS)

    Shazly, M; Salem, S; Bahei-El-Din, Y

    2013-01-01

    The integrity of sandwich structures which are susceptible to impact may deteriorate significantly due to collapse of the core material and delamination of the face sheets. The integration of a thin polyurethane interlayer between the composite face sheet and foam core is known to protect the core material and substantially improve the resistance to impact. The objective of the present work is to characterize the response of sandwich panels, as well as that of the constituents to impact. In particular, the response of polyurethane and foam samples under a range of quasi-static and dynamic loading rates is determined experimentally. Furthermore, the response of sandwich panels to quasi-static indentation and low velocity impact is examined to quantify the extent of damage and how it is affected by the integration of polyurethane interlayers in their construction. This information is useful in the modelling of high velocity impact of sandwich panels; an effort which is currently underway. The results illustrate the benefit of using polyurethane interlayers within the construction of sandwich panels in enhancing their performance under quasi-static indentation and impact loads

  14. Sound-proof Sandwich Panel Design via Metamaterial Concept

    Science.gov (United States)

    Sui, Ni

    Sandwich panels consisting of hollow core cells and two face-sheets bonded on both sides have been widely used as lightweight and strong structures in practical engineering applications, but with poor acoustic performance especially at low frequency regime. Basic sound-proof methods for the sandwich panel design are spontaneously categorized as sound insulation and sound absorption. Motivated by metamaterial concept, this dissertation presents two sandwich panel designs without sacrificing weight or size penalty: A lightweight yet sound-proof honeycomb acoustic metamateiral can be used as core material for honeycomb sandwich panels to block sound and break the mass law to realize minimum sound transmission; the other sandwich panel design is based on coupled Helmholtz resonators and can achieve perfect sound absorption without sound reflection. Based on the honeycomb sandwich panel, the mechanical properties of the honeycomb core structure were studied first. By incorporating a thin membrane on top of each honeycomb core, the traditional honeycomb core turns into honeycomb acoustic metamaterial. The basic theory for such kind of membrane-type acoustic metamaterial is demonstrated by a lumped model with infinite periodic oscillator system, and the negative dynamic effective mass density for clamped membrane is analyzed under the membrane resonance condition. Evanescent wave mode caused by negative dynamic effective mass density and impedance methods are utilized to interpret the physical phenomenon of honeycomb acoustic metamaterials at resonance. The honeycomb metamaterials can extraordinarily improve low-frequency sound transmission loss below the first resonant frequency of the membrane. The property of the membrane, the tension of the membrane and the numbers of attached membranes can impact the sound transmission loss, which are observed by numerical simulations and validated by experiments. The sandwich panel which incorporates the honeycomb metamateiral as

  15. Porous Sandwiched Graphene/Silicon Anodes for Lithium Storage

    International Nuclear Information System (INIS)

    Wei, Liangming; Hou, Zhongyu; Wei, Hao

    2017-01-01

    Highlights: • In situ hydrolysis of tetraethoxysilane within the confined galleries region of graphite oxide. • New porous sandwiched graphene/Si nanocomposites were prepared by magnesium thermal reduction. • The Si nanostructure was compactly sandwiched between two neighboring graphenes. • The Si/graphene anodes deliver large reversible capacity with excellent cycling stability. - Abstract: Porous sandwiched graphene/Si nanocomposites (PG-Si) are prepared by in situ hydrolysis of tetraethoxysilane within the confined gallery region of graphite oxide, and then magnesium thermal reduction of the intra-gallery SiO 2 to Si nanocrystals. The Si nanostructures are in situ formed within the confined gallery region of graphite, and they are compactly sandwiched between two neighboring graphene sheets. This compactly sandwiched structure affords enhanced electron conductivity, and prevents Si nanoparticles from aggregation. Meanwhile, the free voids between neighboring Si nanocrystals alleviate the volume change of Si during cycling. As a consequence, the resulting PG-Si nanocomposites are high-performance anode materials for lithium-ion batteries which show long cycle life (>500 cycles) and high specific charge capacity (1464 mAh g −1 at a current density of 200 mA/g, 920 mAh g −1 at a current density of 1.68A/g after 500 cycles). The Li + diffusion kinetics in PG-Si is also discussed.

  16. Sandwich mapping of schistosomiasis risk in Anhui Province, China.

    Science.gov (United States)

    Hu, Yi; Bergquist, Robert; Lynn, Henry; Gao, Fenghua; Wang, Qizhi; Zhang, Shiqing; Li, Rui; Sun, Liqian; Xia, Congcong; Xiong, Chenglong; Zhang, Zhijie; Jiang, Qingwu

    2015-06-03

    Schistosomiasis mapping using data obtained from parasitological surveys is frequently used in planning and evaluation of disease control strategies. The available geostatistical approaches are, however, subject to the assumption of stationarity, a stochastic process whose joint probability distribution does not change when shifted in time. As this is impractical for large areas, we introduce here the sandwich method, the basic idea of which is to divide the study area (with its attributes) into homogeneous subareas and estimate the values for the reporting units using spatial stratified sampling. The sandwich method was applied to map the county-level prevalence of schistosomiasis japonica in Anhui Province, China based on parasitological data collected from sample villages and land use data. We first mapped the county-level prevalence using the sandwich method, then compared our findings with block Kriging. The sandwich estimates ranged from 0.17 to 0.21% with a lower level of uncertainty, while the Kriging estimates varied from 0 to 0.97% with a higher level of uncertainty, indicating that the former is more smoothed and stable compared to latter. Aside from various forms of reporting units, the sandwich method has the particular merit of simple model assumption coupled with full utilization of sample data. It performs well when a disease presents stratified heterogeneity over space.

  17. Sandwich mapping of schistosomiasis risk in Anhui Province, China

    Directory of Open Access Journals (Sweden)

    Yi Hu

    2015-06-01

    Full Text Available Schistosomiasis mapping using data obtained from parasitological surveys is frequently used in planning and evaluation of disease control strategies. The available geostatistical approaches are, however, subject to the assumption of stationarity, a stochastic process whose joint probability distribution does not change when shifted in time. As this is impractical for large areas, we introduce here the sandwich method, the basic idea of which is to divide the study area (with its attributes into homogeneous subareas and estimate the values for the reporting units using spatial stratified sampling. The sandwich method was applied to map the county-level prevalence of schistosomiasis japonica in Anhui Province, China based on parasitological data collected from sample villages and land use data. We first mapped the county-level prevalence using the sandwich method, then compared our findings with block Kriging. The sandwich estimates ranged from 0.17 to 0.21% with a lower level of uncertainty, while the Kriging estimates varied from 0 to 0.97% with a higher level of uncertainty, indicating that the former is more smoothed and stable compared to latter. Aside from various forms of reporting units, the sandwich method has the particular merit of simple model assumption coupled with full utilization of sample data. It performs well when a disease presents stratified heterogeneity over space.

  18. (ELISA) kit for diagnosis copro-antigens of Giardia lamblia

    African Journals Online (AJOL)

    STORAGESEVER

    2010-08-02

    Aug 2, 2010 ... methods based on antigen scanning of parasites such as enzyme linked immunosorbent assay (ELISA), ... samples. To design this method, a pure antibody against parasite as well as an antibody conjugated to a ..... school children in Santiago, Chile by capture ELISA for the detection of fecal Giardia ...

  19. Agricultural production - Phase 2. Indonesia. ELISA for epidemiology of brucellosis

    International Nuclear Information System (INIS)

    Sutherland, S.S.

    1992-01-01

    This document is a travel report of a three-week mission (from October 13 to November 1, 1991) to Indonesia within the framework of ''The implementation of ELISA technology for the sero-diagnosis of important livestock diseases''. The mission evaluated the implementation of ELISA technology at the Regional Laboratories and its role in the surveillance and control of bovine brucellosis

  20. Multi-Laboratory Validation of Estrone (E1) ELISA Methods

    Science.gov (United States)

    This project is a round-robin evaluation of commercially available Enzyme-Linked Immunosorbent Assay (ELISA) technology to quantitatively or qualitatively measure the hormone estrone (E1) in combined animal feeding operation (CAFO) receiving streams. ELISA is meant to be a simpl...

  1. 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

  2. AN ELISA ASSAY FOR HEME OXYGENASE (HO-1)

    Science.gov (United States)

    An ELISA assay for heme oxygenase (HO-l ) Abstract A double antibody capture ELISA for the HO-l protein has been developed to separately quantitate HO-I protein. The use of 2.5% NP40 detergent greatly assists in freeing HO-l protein from membranes and/or other cel...

  3. 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.

  4. Nanocrystalline Aluminum Truss Cores for Lightweight Sandwich Structures

    Science.gov (United States)

    Schaedler, Tobias A.; Chan, Lisa J.; Clough, Eric C.; Stilke, Morgan A.; Hundley, Jacob M.; Masur, Lawrence J.

    2017-12-01

    Substitution of conventional honeycomb composite sandwich structures with lighter alternatives has the potential to reduce the mass of future vehicles. Here we demonstrate nanocrystalline aluminum-manganese truss cores that achieve 2-4 times higher strength than aluminum alloy 5056 honeycombs of the same density. The scalable fabrication approach starts with additive manufacturing of polymer templates, followed by electrodeposition of nanocrystalline Al-Mn alloy, removal of the polymer, and facesheet integration. This facilitates curved and net-shaped sandwich structures, as well as co-curing of the facesheets, which eliminates the need for extra adhesive. The nanocrystalline Al-Mn alloy thin-film material exhibits high strength and ductility and can be converted into a three-dimensional hollow truss structure with this approach. Ultra-lightweight sandwich structures are of interest for a range of applications in aerospace, such as fairings, wings, and flaps, as well as for the automotive and sports industries.

  5. 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...... this test almost any mode-mixity between pure mode I and mode II can be obtained. A cohesive zone model of the mixed mode fracture process involving large-scale bridging is developed. Results from the analysis are used in Part II, which describes methods and results of a series of experiments....

  6. Calculation of dynamic stresses in viscoelastic sandwich beams using oma

    DEFF Research Database (Denmark)

    Pelayo, F.; Aenlle, M. L.; Ismael, G.

    2017-01-01

    The mechanical response of sandwich elements with viscoelastic core is time and temperature dependent. Laminated glass is a sandwich element where the mechanical behavior of the glass layers is usually considered linear-elastic material whereas the core is made of an amorphous thermoplastic which...... data. In simple structures, analytical mode shapes can be used alternatively to the numerical ones. In this paper, the dynamic stresses on the glass layers of a laminated glass beam have estimated using the experimental acceleration responses measured at 7 points of the beam, and the experimental mode...

  7. 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.

  8. Development of ELISA-based methods to measure the anti-malarial drug chloroquine in plasma and in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Ronn Anita

    2011-08-01

    Full Text Available Abstract Background In Central and South America and Eastern and Southern Africa, Plasmodium vivax infections accounts for 71-81% and 5% of malaria cases, respectively. In these areas, chloroquine (CQ remains the treatment of choice for P. vivax malaria. In addition, CQ has recently proven to be an effective HIV-1 therapeutic agent. There is a dire need to continue monitoring quality of CQ as there is a major influx of substandard and fake formulations into malaria-endemic countries. The use of fake/substandard drugs will result in sub-therapeutic levels endangering the patient and possibly select for parasite resistance. The aim of this study was to develop an inexpensive, simple antibody-based ELISA to measure CQ concentrations in tablets and in plasma. Methods A monoclonal antibody (MAb that reacts with the N-side chain of the CQ molecule was prepared by use of a CQ analogue. A specific and reliable ELISA for detection of CQ was developed. The developed assay was validated by measuring CQ in tablets sold in Denmark, India and Sudan. Furthermore, kinetics of CQ concentrations in plasma of four volunteers, who ingested two tablets of Malarex® containing, 250 mg CQ base, were measured before drug intake, three hours later and thereafter at days 1, 3, 7, 14, 21 and 28. The same plasma samples were simultaneously measured by high performance liquid chromatography (HPLC. Results The ELISA proved an easy-to-handle and very sensitive tool for the detection of CQ with a lower limit of detection at 3.9 ng/ml. ELISA levels of CQ in plasma showed high agreement with the levels obtained by HPLC (r = 0.98. The specificity in the negative control group was 100%. Conclusion The developed ELISA can be used for quality screening of CQ in pharmaceutical formulations and for drug monitoring in malaria and in other infectious diseases, such as HIV, where CQ proved to be an effective therapeutic agent. The methodology has been exploited to develop monoclonal

  9. Biotin/avidin sandwich enzyme-linked immunosorbent assay for Culicidae mosquito blood meal identification

    Directory of Open Access Journals (Sweden)

    A. M. Marassá

    2008-01-01

    Full Text Available The knowledge of mosquitoes Culicidae host feeding patterns is basic to understand the roles of different species and to indicate their importance in the epidemiology of arthropod-borne diseases. A laboratory assay was developed aiming at standardizing the biotin-avidin sandwich enzyme-linked immunosorbent assay, which was unprecedented for mosquito blood meal identification. The enzyme-linked immunosorbent assay (ELISA activity was evaluated by the detection of titers on each sample of the 28 blood-fed Culex quinquefasciatus. In light of the high sensitivity that the technique permits, by means of small quantities of specific antibodies commercially provided and phosphatase substrate which reinforces additional dilutions, human and rat blood meals were readily identified in all laboratory-raised Culex quinquefasciatus tested. The assay was effective to detect human blood meal dilutions up to 1:4,096, which enables the technique to be applied in field studies. Additionally, the present results indicate a significant difference between the detection patterns recorded from human blood meal which corroborate the results of host feeding patterns.

  10. Production of monoclonal antibodies for sandwich immunoassay detection of Pacific ciguatoxins.

    Science.gov (United States)

    Tsumuraya, Takeshi; Fujii, Ikuo; Hirama, Masahiro

    2010-10-01

    Ciguatoxins are the major causative toxins of ciguatera seafood poisoning. Limited availability of ciguatoxins has hampered the development of a reliable and specific immunoassay for detecting these toxins in contaminated fish. Monoclonal antibodies (mAbs) specific against both ends of Pacific ciguatoxins CTX3C and 51-hydroxyCTX3C were prepared by immunization of mice with the protein conjugates of rationally designed synthetic haptens in place of the natural toxin. Haptenic groups that possess a surface area larger than 400 A(2) were required to produce mAbs that can bind strongly to CTX3C or 51-hydroxyCTX3C. A direct sandwich enzyme-linked immunosorbent assay (ELISA) using these mAbs was established to detect CTX3C and 51-hydroxyCTX3C at the ppb level with no cross-reactivity against the other marine toxins, including brevetoxin A, brevetoxin B, okadaic acid, or maitotoxin. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. Application of fibre reinforced plastic sandwich structures for automotive crashworthiness applications

    NARCIS (Netherlands)

    Lukaszewicz, D.; Blok, L.G.; Kratz, J.; Ward, C.; Kassapoglou, C.; Elmarakbi, A.; Araújo, A.L.

    2016-01-01

    In this work the application of fibre reinforced plastic (FRP) sandwich
    structures, with particular focus on aramid fibre tufted sandwiches is being studied for
    automotive crashworthiness applications using impact testing and numerical simulation.

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

    KAUST Repository

    Mohammed, Omar F.; Banavoth, Murali; Saidaminov, Makhsud I.; Abdelhady, Ahmed L.; Pan, Jun; Liu, Jiakai; Peng, Wei; Bakr, Osman

    2016-01-01

    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

  13. 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.

  14. Gravity sag of sandwich panel assemblies as applied to precision cathode strip chamber structural design

    International Nuclear Information System (INIS)

    Horvath, J.

    1993-01-01

    The relationship between gravity sag of a precision cathode strip chamber and its sandwich panel structural design is explored parametrically. An algorithm for estimating the dominant component of gravity sag is defined. Graphs of normalized gravity sag as a function of gap frame width and material, sandwich core edge filler width and material, panel skin thickness, gap height, and support location are calculated using the gravity sag algorithm. The structural importance of the sandwich-to-sandwich ''gap frame'' connection is explained

  15. 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 and app...

  16. Compressive Behaviour and Energy Absorption of Aluminium Foam Sandwich

    Science.gov (United States)

    Endut, N. A.; Hazza, M. H. F. Al; Sidek, A. A.; Adesta, E. T. Y.; Ibrahim, N. A.

    2018-01-01

    Development of materials in automotive industries plays an important role in order to retain the safety, performance and cost. Metal foams are one of the idea to evolve new material in automotive industries since it can absorb energy when it deformed and good for crash management. Recently, new technology had been introduced to replace metallic foam by using aluminium foam sandwich (AFS) due to lightweight and high energy absorption behaviour. Therefore, this paper provides reliable data that can be used to analyze the energy absorption behaviour of aluminium foam sandwich by conducting experimental work which is compression test. Six experiments of the compression test were carried out to analyze the stress-strain relationship in terms of energy absorption behavior. The effects of input variables include varying the thickness of aluminium foam core and aluminium sheets on energy absorption behavior were evaluated comprehensively. Stress-strain relationship curves was used for energy absorption of aluminium foam sandwich calculation. The result highlights that the energy absorption of aluminium foam sandwich increases from 12.74 J to 64.42 J respectively with increasing the foam and skin thickness.

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

    African Journals Online (AJOL)

    Bladder neck stenosis occurred in 3 patients and was successfully treated with bladder neck incision. Conclusions: The sandwich combination of TURP and TUVP for the surgical treatment of BPH with volume larger than 40cc had satisfactory patient safety profile and resulted in significant improvement in IPSS, Qmax and ...

  18. Acoustic wave spread in superconducting-normal-superconducting sandwich

    International Nuclear Information System (INIS)

    Urushadze, G.I.

    2004-01-01

    The acoustic wave spread, perpendicular to the boundaries between superconducting and normal metals in superconducting-normal-superconducting (SNS) sandwich has been considered. The alternate current flow sound induced by the Green function method has been found and the coefficient of the acoustic wave transmission through the junction γ=(S 1 -S 2 )/S 1 , (where S 1 and S 2 are average energy flows formed on the first and second boundaries) as a function of the phase difference between superconductors has been investigated. It is shown that while the SNS sandwich is almost transparent for acoustic waves (γ 0 /τ), n=0,1,2, ... (where τ 0 /τ is the ratio of the broadening of the quasiparticle energy levels in impurity normal metal as a result of scattering of the carriers by impurities 1/τ to the spacing between energy levels 1/τ 0 ), γ=2, (S 2 =-S 1 ), which corresponds to the full reflection of the acoustic wave from SNS sandwich. This result is valid for the limit of a pure normal metal but in the main impurity case there are two amplification and reflection regions for acoustic waves. The result obtained shows promise for the SNS sandwich as an ideal mirror for acoustic wave reflection

  19. 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...

  20. Investigation on Wall Panel Sandwiched With Lightweight Concrete

    Science.gov (United States)

    Lakshmikandhan, K. N.; Harshavardhan, B. S.; Prabakar, J.; Saibabu, S.

    2017-08-01

    The rapid population growth and urbanization have made a massive demand for the shelter and construction materials. Masonry walls are the major component in the housing sector and it has brittle characteristics and exhibit poor performance against the uncertain loads. Further, the structure requires heavier sections for carrying the dead weight of masonry walls. The present investigations are carried out to develop a simple, lightweight and cost effective technology for replacing the existing wall systems. The lightweight concrete is developed for the construction of sandwich wall panel. The EPS (Expanded Polystyrene) beads of 3 mm diameter size are mixed with concrete and developed a lightweight concrete with a density 9 kN/m3. The lightweight sandwich panel is cast with a lightweight concrete inner core and ferrocement outer skins. This lightweight wall panel is tested for in-plane compression loading. A nonlinear finite element analysis with damaged plasticity model is carried out with both material and geometrical nonlinearities. The experimental and analytical results were compared. The finite element study predicted the ultimate load carrying capacity of the sandwich panel with reasonable accuracy. The present study showed that the lightweight concrete is well suitable for the lightweight sandwich wall panels.

  1. 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)

  2. Damage assessment of compression loaded debond damaged sandwich panels

    DEFF Research Database (Denmark)

    Moslemian, Ramin; Berggreen, Christian; Quispitupa, Amilcar

    2010-01-01

    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...

  3. An Assessment of the Speed Reading Ability of Sandwich Students ...

    African Journals Online (AJOL)

    The paper discusses the concept and usefulness of rapid reading. It also reports a study in which the Faculty of Education, University of Lagos, Nigeria Sandwich students formed the subjects. Their pre-training reading speed and comprehension scores were determined through a pre-test, after which they were subjected to ...

  4. 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.

  5. Enhanced detection levels in a semi-automated sandwich ...

    African Journals Online (AJOL)

    A peptide nucleic acid (PNA) signal probe was tested as a replacement for a typical DNA oligonucleotidebased signal probe in a semi-automated sandwich hybridisation assay designed to detect the harmful phytoplankton species Alexandrium tamarense. The PNA probe yielded consistently higher fluorescent signal ...

  6. Nonglobal proof of the thin--sandwich conjecture

    International Nuclear Information System (INIS)

    Pereira, C.M.

    1981-01-01

    A gravitational thin--sandwich conjecture was first proposed by Wheeler and coworkers during the period 1962--4. The present paper contains a proof of the nonglobal form of this gravitational thin--sandwich conjecture. The proof (a) applies for arbitrary choices of the spatial metric and its time derivative; and (b) demonstrates the existence on a spacelike three-surface of solutions which satisfy conditions of continuity known to be sufficient to obtain existence and uniqueness of solutions to Einstein's equations off the three-surface and existence and uniqueness of geodesics. Riquier's existence theorem plays an important role in the proof. The relationship of the present results to previous work is discussed. Some global questions associated with the thin--sandwich conjecture are clarified. Some aspects of the relationship of the thin--sandwich conjecture to the problem of the quantization of the gravitational field are noted. Both the vacuum case and the case of a nonviscous fluid are included. The discussion allows for an arbitrary equation of state p = p

  7. 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...

  8. Interfacial Crack Arrest in Sandwich Panels with Embedded Crack Stoppers Subjected to Fatigue Loading

    DEFF Research Database (Denmark)

    Martakos, G.; Andreasen, J. H.; Berggreen, Christian

    2017-01-01

    A novel crack arresting device has been implemented in sandwich panels and tested using a special rig to apply out-of-plane loading on the sandwich panel face-sheets. Fatigue crack propagation was induced in the face-core interface of the sandwich panels which met the crack arrester. The effect o...

  9. 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

  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. Antibody-based assay discriminates Zika virus infection from other flaviviruses.

    Science.gov (United States)

    Balmaseda, Angel; Stettler, Karin; Medialdea-Carrera, Raquel; Collado, Damaris; Jin, Xia; Zambrana, José Victor; Jaconi, Stefano; Cameroni, Elisabetta; Saborio, Saira; Rovida, Francesca; Percivalle, Elena; Ijaz, Samreen; Dicks, Steve; Ushiro-Lumb, Ines; Barzon, Luisa; Siqueira, Patricia; Brown, David W G; Baldanti, Fausto; Tedder, Richard; Zambon, Maria; de Filippis, A M Bispo; Harris, Eva; Corti, Davide

    2017-08-01

    Zika virus (ZIKV) is a mosquito-borne flavivirus that emerged recently as a global health threat, causing a pandemic in the Americas. ZIKV infection mostly causes mild disease, but is linked to devastating congenital birth defects and Guillain-Barré syndrome in adults. The high level of cross-reactivity among flaviviruses and their cocirculation has complicated serological approaches to differentially detect ZIKV and dengue virus (DENV) infections, accentuating the urgent need for a specific and sensitive serological test. We previously generated a ZIKV nonstructural protein 1 (NS1)-specific human monoclonal antibody, which we used to develop an NS1-based competition ELISA. Well-characterized samples from RT-PCR-confirmed patients with Zika and individuals exposed to other flavivirus infections or vaccination were used in a comprehensive analysis to determine the sensitivity and specificity of the NS1 blockade-of-binding (BOB) assay, which was established in laboratories in five countries (Nicaragua, Brazil, Italy, United Kingdom, and Switzerland). Of 158 sera/plasma from RT-PCR-confirmed ZIKV infections, 145 (91.8%) yielded greater than 50% inhibition. Of 171 patients with primary or secondary DENV infections, 152 (88.9%) scored negative. When the control group was extended to patients infected by other flaviviruses, other viruses, or healthy donors ( n = 540), the specificity was 95.9%. We also analyzed longitudinal samples from DENV-immune and DENV-naive ZIKV infections and found inhibition was achieved within 10 d postonset of illness and maintained over time. Thus, the Zika NS1 BOB assay is sensitive, specific, robust, simple, low-cost, and accessible, and can detect recent and past ZIKV infections for surveillance, seroprevalence studies, and intervention trials.

  12. Grantee Spotlight: Elisa Rodriguez, Ph.D., M.S.

    Science.gov (United States)

    Dr. Elisa M. Rodriguez tests the feasibility of community-based participatory research approaches to engaging Hispanics, African Americans, and the medically underserved in the Buffalo, NY area in biospecimen donation for cancer research.

  13. Direct Competitive Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Kohl, Thomas O; Ascoli, Carl A

    2017-07-05

    The competitive enzyme-linked immunosorbent assay (ELISA) (cELISA; also called an inhibition ELISA) is designed so that purified antigen competes with antigen in the test sample for binding to an antibody that has been immobilized in microtiter plate wells. The same concept works if the immobilized molecule is antigen and the competing molecules are purified labeled antibody versus antibody in a test sample. Direct cELISAs incorporate labeled antigen or antibody, whereas indirect assay configurations use reporter-labeled secondary antibodies. The cELISA is very useful for determining the concentration of small-molecule antigens in complex sample mixtures. In the direct cELISA, antigen-specific capture antibody is adsorbed onto the microtiter plate before incubation with either known standards or unknown test samples. Enzyme-linked antigen (i.e., labeled antigen) is also added, which can bind to the capture antibody only when the antibody's binding site is not occupied by either the antigen standard or antigen in the test samples. Unbound labeled and unlabeled antigens are washed away and substrate is added. The amount of antigen in the standard or the test sample determines the amount of reporter-labeled antigen bound to antibody, yielding a signal that is inversely proportional to antigen concentration within the sample. Thus, the higher the antigen concentration in the test sample, the less labeled antigen is bound to the capture antibody, and hence the weaker is the resultant signal. © 2017 Cold Spring Harbor Laboratory Press.

  14. Development of monoclonal antibodies to pre-haptoglobin 2 and their use in an enzyme-linked immunosorbent assay (ELISA).

    Science.gov (United States)

    Flanagan, J J; Arjomandi, A; Delanoy, M L; Du Paty, E; Galea, P; Laune, D; Rieunier, F; Walker, R P; Binder, S R

    2014-04-01

    Haptoglobins (HPs) are alpha 2-globulin proteins that bind free hemoglobin in plasma to prevent oxidative damage. HPs are produced as preproteins that are proteolytically cleaved in the ER into alpha and beta chains prior to forming mature, functional tetramers. Two alleles exist in humans (HP1 and HP2), therefore three genotypes are present in the population, i.e., HP1-1, HP2-1, and HP2-2. A biochemical role for nascent haptoglobin 2 (pre-haptoglobin 2 or pre-HP2) as the only known modulator of intestinal permeability has been established. In addition, elevated levels of serum pre-HP2 have been detected in multiple conditions including celiac disease and type I diabetes, which are believed to result in part through dysregulation of the intestinal barrier. In this study, we report the development of a monoclonal antibody that is specific for pre-HP2 with a binding affinity in the nanomolar range. Additional antibodies with specificities for preHP but not mature haptoglobin were also characterized. A sandwich enzyme-linked immunosorbent assay (ELISA) was established and validated. The ELISA showed high specificity for pre-HP2 even in the presence of excess pre-HP1 or mature haptoglobins, and has excellent linearity and inter- and intra-assay reproducibility with a working range from 3.1ng/mL to 200ng/mL. Testing of sera from 76 healthy patients revealed a non-Gaussian distribution of pre-HP2 levels with a mean concentration of 221.2ng/mL (95% CI: 106.5-335.9ng/mL) and a median value of 23.9ng/mL. Compared to current approaches, this ELISA offers a validated, monoclonal-based method with high sensitivity and specificity for measuring pre-HP2 in human serum. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. An enzyme-linked immunosorbent assay (ELISA) for quantification of human collectin 11 (CL-11, CL-K1)

    Science.gov (United States)

    Selman, L.; Henriksen, M.L.; Brandt, J.; Palarasah, Y.; Waters, A.; Beales, P.L.; Holmskov, U.; Jørgensen, T.J.D.; Nielsen, C.; Skjodt, K.; Hansen, S.

    2012-01-01

    Collectin 11 (CL-11), also referred to as collectin kidney 1 (CL-K1), is a pattern recognition molecule that belongs to the collectin group of proteins involved in innate immunity. It interacts with glycoconjugates on pathogen surfaces and has been found in complex with mannose-binding lectin-associated serine protease 1 (MASP-1) and/or MASP-3 in circulation. Mutation in the CL-11 gene was recently associated with the developmental syndrome 3MC. In the present study, we established and thoroughly validated a sandwich enzyme-linked immunosorbent assay (ELISA) based on two different monoclonal antibodies. The assay is highly sensitive, specific and shows excellent quantitative characteristics such as reproducibility, dilution linearity and recovery (97.7–104%). The working range is 0.15–34 ng/ml. The CL-11 concentration in two CL-11-deficient individuals affected by the 3MC syndrome was determined to be below 2.1 ng/ml. We measured the mean serum CL-11 concentration to 284 ng/ml in 100 Danish blood donors, with a 95% confidence interval of 269–299 ng/ml. There was no significant difference in the CL-11 concentration measured in matched serum and plasma samples. Storage of samples and repeated freezing and thawing to a certain extent did not influence the ELISA. This ELISA offers a convenient and reliable method for studying CL-11 levels in relation to a variety of human diseases and syndromes. PMID:22301270

  16. 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.

  17. 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.

  18. 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.

  19. Theoretical prediction on corrugated sandwich panels under bending loads

    Science.gov (United States)

    Shu, Chengfu; Hou, Shujuan

    2018-05-01

    In this paper, an aluminum corrugated sandwich panel with triangular core under bending loads was investigated. Firstly, the equivalent material parameters of the triangular corrugated core layer, which could be considered as an orthotropic panel, were obtained by using Castigliano's theorem and equivalent homogeneous model. Secondly, contributions of the corrugated core layer and two face panels were both considered to compute the equivalent material parameters of the whole structure through the classical lamination theory, and these equivalent material parameters were compared with finite element analysis solutions. Then, based on the Mindlin orthotropic plate theory, this study obtain the closed-form solutions of the displacement for a corrugated sandwich panel under bending loads in specified boundary conditions, and parameters study and comparison by the finite element method were executed simultaneously.

  20. 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.

  1. Buckling analysis of SMA bonded sandwich structure – using FEM

    Science.gov (United States)

    Katariya, Pankaj V.; Das, Arijit; Panda, Subrata K.

    2018-03-01

    Thermal buckling strength of smart sandwich composite structure (bonded with shape memory alloy; SMA) examined numerically via a higher-order finite element model in association with marching technique. The excess geometrical distortion of the structure under the elevated environment modeled through Green’s strain function whereas the material nonlinearity counted with the help of marching method. The system responses are computed numerically by solving the generalized eigenvalue equations via a customized MATLAB code. The comprehensive behaviour of the current finite element solutions (minimum buckling load parameter) is established by solving the adequate number of numerical examples including the given input parameter. The current numerical model is extended further to check the influence of various structural parameter of the sandwich panel on the buckling temperature including the SMA effect and reported in details.

  2. Fracture Characterization of Sandwich Face/Core Interfaces

    DEFF Research Database (Denmark)

    Manca, Marcello

    of load transfer between the faces and the core layer is lost, the debonds are considered as primary damage initiators. Under fatigue loading the debonds may evolve into cracks that cause a reduction in structural performance and consequent failure. At present most structural design is based on “life-time...... of sandwich structures is defects that are introduced in the manufacturing process. It is inevitable that areas of the face sheets will not fully adhere to the core resulting in defects known as “debonds”. Debonds can also be induced in-service due to e.g. localised impact loading or overloading. As the means...... 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...

  3. Enhanced Performance of Sandwich Structures by Improved Damage Tolerance

    DEFF Research Database (Denmark)

    Martakos, Georgios

    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...... concentrations in the foam core material on the back side of the peel stopper. By use of the developed numerical fracture mechanics based modelling tools, both fatigue crack growth and crack arrest in the specimens were simulated. It was shown that the strains responsible for crack re-initiation can...

  4. 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. 23 used was 21.5 L (SD = 4.9).The mean post-operative hospital stay was 3.5 days (range 3- 4 days). Overall,. 11 (19%) patients had blood transfusion, there was no incidence of TUR syndrome and one mortality was recorded ...

  5. Fluid Structure Interaction Effect on Sandwich Composite Structures

    Science.gov (United States)

    2011-09-01

    far back as ancient Egyptian times in the use of straw and bricks, or more recently in the last century with the use of steel rebar in concrete ...construction of sandwich composites; however, this particular material was selected for its uniform pattern and translucent qualities after it is wetted out...excellent fire retardant and corrosion resistant qualities making it a natural selection for shipboard applications. The same translucent qualities

  6. Sandwich-panels based on penopolisocyanurate and mineral wool

    OpenAIRE

    Burtzeva M.; Mednikova E.

    2017-01-01

    Sandwich panel is a self-supporting structure consisting of two steel zinc-coated profiles with a layer of heat retainer. It is used as roofing and walling material. Widely is used in industrial construction, shopping centres, sports complexes, chilling and freezing chambers, storage buildings and quickly erectable housing. The classical basis of heat-insulating layer (core panel) products is used mineral wool insulation materials. This material is resistant to deformation, non-flammable,...

  7. The use of enzyme-linked immunosorbent assay (ELISA) for the diagnosis and monitoring of foot-and-mouth disease in the Philippines

    International Nuclear Information System (INIS)

    Verin, B.C.; Arvesu, R.M.

    2000-01-01

    The establishment and use of the indirect sandwich ELISA for the detection of foot-and-mouth disease (FMD) virus antigen sero-types O, A and C and the liquid phase blocking ELISA (LPB-ELISA) for antibody levels against similar FMD sero-types has been adopted for routine diagnosis at the FMD diagnostic laboratory, PAHC. A total of 552 epithelial samples and 4401 serum samples were tested starting 1995 to 1998. Out of 552, 84 (17.9%) were found negative and 468 (84.78%) diagnosed as positive for sero-types O and C (42% of the total positives). Within 4 years, 62 representative samples were sent to WRL for FMD for confirmation diagnosis. From 62 samples sent 54 (87%) were diagnosed as positive and 8 (12.9%) were negative. Serum samples received were either for diagnosis (71 samples), surveillance (3002 serum), post vaccination titre (1303 serum) and for the FAO/IAEA external quality assurance programme (25 samples) by the FAO/IAEA Co-ordinated Research Project on FMD. The assay has been a useful tool in the fast diagnosis and confirmation of FMD suspect cases and in the measurement of antibodies against FMDV in serum samples from all animals either vaccinated or infected. In the future, the assay will be use for potency testing of imported vaccines and for monitoring and surveillance purposes to show freedom from disease for the support documentation from OIE. (author)

  8. Lab-on-chip system combining a microfluidic-ELISA with an array of amorphous silicon photosensors for the detection of celiac disease epitopes

    Directory of Open Access Journals (Sweden)

    Francesca Costantini

    2015-12-01

    Full Text Available This work presents a lab-on-chip system, which combines a glass-polydimethilsiloxane microfluidic network and an array of amorphous silicon photosensors for the diagnosis and follow-up of Celiac disease. The microfluidic chip implements an on-chip enzyme-linked immunosorbent assay (ELISA, relying on a sandwich immunoassay between antibodies against gliadin peptides (GPs and a secondary antibody marked with horseradish peroxidase (Ig-HRP. This enzyme catalyzes a chemiluminescent reaction, whose light intensity is detected by the amorphous silicon photosensors and transduced into an electrical signal that can be processed to recognize the presence of antibodies against GPs in the serum of people affected by Celiac syndrome.The correct operation of the developed lab-on-chip has been demonstrated using rabbit serum in the microfluidic ELISA. In particular, optimizing the dilution factors of both sera and Ig-HRP samples in the flowing solutions, the specific and non-specific antibodies against GPs can be successfully distinguished, showing the suitability of the presented device to effectively screen celiac disease epitopes. Keywords: Lab-on-chip, Celiac disease, Microfluidics, On-chip detection, ELISA, Amorphous silicon photosensors

  9. 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.

  10. Sandwich-structured hollow fiber membranes for osmotic power generation

    KAUST Repository

    Fu, Feng Jiang; Zhang, Sui; Chung, Neal Tai-Shung

    2015-01-01

    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.

  11. Generation of Elliptically Polarized Terahertz Waves from Antiferromagnetic Sandwiched Structure.

    Science.gov (United States)

    Zhou, Sheng; Zhang, Qiang; Fu, Shu-Fang; Wang, Xuan-Zhang; Song, Yu-Ling; Wang, Xiang-Guang; Qu, Xiu-Rong

    2018-04-01

    The generation of elliptically polarized electromagnetic wave of an antiferromagnetic (AF)/dielectric sandwiched structure in the terahertz range is studied. The frequency and external magnetic field can change the AF optical response, resulting in the generation of elliptical polarization. An especially useful geometry with high levels of the generation of elliptical polarization is found in the case where an incident electromagnetic wave perpendicularly illuminates the sandwiched structure, the AF anisotropy axis is vertical to the wave-vector and the external magnetic field is pointed along the wave-vector. In numerical calculations, the AF layer is FeF2 and the dielectric layers are ZnF2. Although the effect originates from the AF layer, it can be also influenced by the sandwiched structure. We found that the ZnF2/FeF2/ZnF2 structure possesses optimal rotation of the principal axis and ellipticity, which can reach up to about thrice that of a single FeF2 layer.

  12. Sandwiched Rényi divergence satisfies data processing inequality

    International Nuclear Information System (INIS)

    Beigi, Salman

    2013-01-01

    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

  13. 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.

  14. 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.

  15. Polyclonal Antibody-based ELISA in combination with specific PCR amplification of ITS 1 regions for the detection and quantitation of Lasiodiplodia theobromae, causal agent of 2 gummosis in cashew nut plants

    NARCIS (Netherlands)

    Muniz, C.R.; Freire, F.C.O.; Viana, F.M.P.; Cardoso, J.E.; Correia, D.; Jalink, H.; Kema, G.H.J.; Silva, G.F.; Guedes, M.I.F.

    2012-01-01

    Members of Botryosphaeriaceae family are associated with serious diseases in different plants 18 across the world. In cashew nut plants (Anacardium occidentale L.), the fungus Lasiodiplodia 19 theobromae causes a severe group of symptoms related to gummosis that results in decreased nut 20

  16. 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.

  17. 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

    Background: 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. Materials and Methods: 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. Results: 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. 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. PMID:27376040

  18. Evaluation of SD BIOLINE H. pylori Ag rapid test against double ELISA with SD H. pylori Ag ELISA and EZ-STEP H. pylori Ag ELISA tests.

    Science.gov (United States)

    Negash, Markos; Kassu, Afework; Amare, Bemnet; Yismaw, Gizachew; Moges, Beyene

    2018-01-01

    Helicobacter pylori antibody titters fall very slowly even after successful treatment. Therefore, tests detecting H. pylori antibody lack specificity and sensitivity. On the other hand, H. pylori stool antigen tests are reported as an alternative assay because of their reliability and simplicity. However, the comparative performance of H. pylori stool antigen tests for detecting the presence of the bacterium in clinical specimens in the study area is not assessed. Therefore, in this study we evaluated the performance of SD BIOLINE H. pylori Ag rapid test with reference to the commercially available EZ- STEP ELISA and SD BIOLINE H. pylori Ag ELISA tests. Stool samples were collected to analyse the diagnostic performance of SD BIOLINE H. pylori Ag rapid test kit using SD H. pylori Ag ELISA kit and EZ- STEP ELISA tests as a gold standard. Serum samples were also collected from each patient to test for the presence of H. pylori antibodies using dBest H. pylori Test Disk. Sensitivity, specificity, predictive values and kappa value are assessed. P values H. pylori Ag rapid test were: 95.6% (95% CI, 88.8-98.8), 92.5% (95%CI, 89-94.1%), 86.7% (95% CI, 80.5-89.6), and 97.6% (95% CI, 993.9-99.3) respectively. The performance of SD BIOLINE H. pylori Ag rapid test was better than the currently available antibody test in study area. Therefore, the SD BIOLINE Ag rapid stool test could replace and be used to diagnose active H. pylori infection before the commencement of therapy among dyspeptic patients.

  19. Comparative evaluation of competitive ELISA test in Colombian cattle

    International Nuclear Information System (INIS)

    Marino, O.; Rueda, E.; Sedano, L.; Zuniga, I.; Calderon, C.; Ortega, A.; Puentes, A.

    1998-01-01

    In order to contribute to the definition of the best ELISA test for screening and differential diagnosis of Brucella abortus to be applied for control programmes, a total of 2971 sera from Colombian cattle were tested for brucellosis. Conventional agglutination tests, Buffered Plate antigen test (BPAT) and Rose Bengal (RB) as well as Complement Fixation test (CFT) (Alton, et al. 1988) were used comparatively. Radial immunodiffusion test (RID) was also performed to all sera. The sera were also tested using four different ELISAs: indirect ELISA from FAO/IAEA and the indirect ELISA modified by Nielsen, et al. 1992 as well as two competitive ELISAs: one competitive ELISA used B. abortus O-polysaccharide antigen and an enzyme conjugated monoclonal to the O-polysaccharide for competition and detection. The second competitive ELISA used lipopolysaccharide (sLPS) antigen, a different monoclonal antibody for competition but also specific for the O-polysaccharide and a commercially available goat anti-mouse IgG enzyme conjugate for detection. The sera were analyzed based on its population status, 987 positive obtained from Brucella abortus infected herds based on clinical and/or bacteriological evidence and a high prevalence of brucellosis, CFT percentage of positive animals in the herd was greater than 5%. Eight hundred sixty six (866) negative sera from non-vaccinated cattle from a brucellosis free area and 1118 negative sera obtained from reglamentary vaccinated areas under a free herd program. Initial cut-off values were derived using negative serum samples. The diagnostic sensitivity and specificity was defined from frequency histograms based on this cut-off values and using 2x2 tables, corresponding confidence limits (95%) were calculated. The data were also analysed using signal detection analysis (ROC). Kappa statistics was determined for all tests and populations, accuracy was used as index of comparison to evaluate different assays. The data support the initial

  20. ITO-TiN-ITO Sandwiches for Near-Infrared Plasmonic Materials.

    Science.gov (United States)

    Chen, Chaonan; Wang, Zhewei; Wu, Ke; Chong, Haining; Xu, Zemin; Ye, Hui

    2018-05-02

    Indium tin oxide (ITO)-based sandwich structures with the insertion of ultrathin (ITO layers show TiN-thickness-dependent properties, which lead to moderate and tunable effective permittivities for the sandwiches. The surface plasmon polaritons (SPP) of the ITO-TiN-ITO sandwich at the telecommunication window (1480-1570 nm) are activated by prism coupling using Kretschmann configuration. Compared with pure ITO films or sandwiches with metal insertion, the reflectivity dip for sandwiches with TiN is relatively deeper and wider, indicating the enhanced coupling ability in plasmonic materials for telecommunications. The SPP spatial profile, penetration depth, and degree of confinement, as well as the quality factors, demonstrate the applicability of such sandwiches for NIR plasmonic materials in various devices.

  1. Universal quantum dot-based sandwich-like immunoassay strategy for rapid and ultrasensitive detection of small molecules using portable and reusable optofluidic nano-biosensing platform

    International Nuclear Information System (INIS)

    Zhou, Liping; Zhu, Anna; Lou, Xuening; Song, Dan; Yang, Rong; Shi, Hanchang; Long, Feng

    2016-01-01

    . - Highlights: • Sandwich-like immunoassay strategy was used for rapid detection of small molecule. • Optofluidic sensing platform investigated the sandwich-like immunoassay mechanism. • A versatile optical biosensor like ELISA was developed using QD-immunoprobe. • No modified primary antibody with highest activity improved biosensor performance. • QD-immunoprobe-based biosensor was highly sensitive for small molecule detection. • Reusable sensing surface was applied for multiple sensing events with low cost.

  2. Universal quantum dot-based sandwich-like immunoassay strategy for rapid and ultrasensitive detection of small molecules using portable and reusable optofluidic nano-biosensing platform

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Liping; Zhu, Anna; Lou, Xuening; Song, Dan; Yang, Rong [School of Environment and Natural Resources, Renmin University of China, Beijing (China); Shi, Hanchang [School of Environment, Tsinghua University, Beijing (China); Long, Feng, E-mail: longf04@ruc.edu.cn [School of Environment and Natural Resources, Renmin University of China, Beijing (China)

    2016-01-28

    . - Highlights: • Sandwich-like immunoassay strategy was used for rapid detection of small molecule. • Optofluidic sensing platform investigated the sandwich-like immunoassay mechanism. • A versatile optical biosensor like ELISA was developed using QD-immunoprobe. • No modified primary antibody with highest activity improved biosensor performance. • QD-immunoprobe-based biosensor was highly sensitive for small molecule detection. • Reusable sensing surface was applied for multiple sensing events with low cost.

  3. Sound insulation of composite cylindrical shells: a comparison between a laminated and a sandwich cylinder

    OpenAIRE

    Yuan, Chongxin; Roozen, Bert; Bergsma, Otto; Beukers, Adriaan

    2012-01-01

    The fuselages of aircraft are modeled as a cylinder in this paper, and the sound insulations of a sandwich cylinder and a laminated cylinder are studied both experimentally and numerically. The cylinders are excited by an acoustic pressure and a mechanical force respectively. Results show that under acoustic excitation, the sandwich cylinder and the laminated one have a similar sound insulation below 3000 Hz, but the sandwich cylinder has a much larger sound insulation at higher frequencies. ...

  4. Blast-Resistant Improvement of Sandwich Armor Structure with Aluminum Foam Composite

    OpenAIRE

    Yang, Shu; Qi, Chang

    2013-01-01

    Sandwich armor structures with aluminum foam can be utilized to protect a military vehicle from harmful blast load such as a landmine explosion. In this paper, a system-level dynamic finite element model is developed to simulate the blast event and to evaluate the blast-resistant performance of the sandwich armor structure. It is found that a sandwich armor structure with only aluminum foam is capable of mitigating crew injuries under a moderate blast load. However, a severe blast load causes...

  5. Elisa development for detection of glyphosat resistant gm soybean

    Directory of Open Access Journals (Sweden)

    Владислав Геннадійович Спиридонов

    2015-11-01

    Full Text Available During research we have utilized recombinant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS, conferring resistance to glyphosate for GM soybean, for the hen immunization and obtaining specific yolk antibodies IgY. Stages of ELISA development that can detect at least 0,1 % of GM-soybean resistant to glyphosate were present

  6. Detection of antibodies to the 20s proteasome by ELISA

    DEFF Research Database (Denmark)

    Jørgensen, Karin Meinike; Frederiksen, Jette Lautrup; Nielsen, Christoffer Tandrup

    2013-01-01

    The presence of antibodies against the 20S proteasome has been correlated with diseases like multiple sclerosis (MS) and systemic lupus erythematosus (SLE) but no definite association has been established. In order to investigate this further, we optimized an ELISA for proteasome antibodies...

  7. An experiment to test in-field pointing for Elisa

    Science.gov (United States)

    Brugger, Christina; Broll, Bernhard; Fitzsimons, Ewan; Johann, Ulrich; Jonke, Wouter; Lucarelli, Stefano; Nikolov, Susanne; Voert, Martijn; Weise, Dennis; Witvoet, Gert

    2017-11-01

    The evolved Laser Interferometer Space Antenna (eLISA) Mission is being developed to detect and characterise gravitational waves by measuring pathlength changes between free flying inertial test masses over a baseline of order 1 Gm. Here the observed astrophysical events and objects lie in a frequency range between 30 μHz and 1 Hz (the LISA measurement band, LMB).

  8. Opportunities and challenges when pooling milk samples using ELISA

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Andresen, Lars Ole; Hisham Beshara Halasa, Tariq

    2017-01-01

    -positive samples by pooling. To illustrate this, the sensitivity of antibody ELISA on pooled samples of bovine milk for Salmonella Dublin, Mycobacterium avium spp. paratuberculosis, and bovine virus diarrhea was tested. For these milk assays, the analytical sensitivity decreased rapidly with increasing pool sizes...

  9. 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.

  10. Energy absorption capabilities of composite sandwich panels under blast loads

    Science.gov (United States)

    Sankar Ray, Tirtha

    As blast threats on military and civilian structures continue to be a significant concern, there remains a need for improved design strategies to increase blast resistance capabilities. The approach to blast resistance proposed here is focused on dissipating the high levels of pressure induced during a blast through maximizing the potential for energy absorption of composite sandwich panels, which are a competitive structural member type due to the inherent energy absorption capabilities of fiber reinforced polymer (FRP) composites. Furthermore, the middle core in the sandwich panels can be designed as a sacrificial layer allowing for a significant amount of deformation or progressive failure to maximize the potential for energy absorption. The research here is aimed at the optimization of composite sandwich panels for blast mitigation via energy absorption mechanisms. The energy absorption mechanisms considered include absorbed strain energy due to inelastic deformation as well as energy dissipation through progressive failure of the core of the sandwich panels. The methods employed in the research consist of a combination of experimentally-validated finite element analysis (FEA) and the derivation and use of a simplified analytical model. The key components of the scope of work then includes: establishment of quantified energy absorption criteria, validation of the selected FE modeling techniques, development of the simplified analytical model, investigation of influential core architectures and geometric parameters, and investigation of influential material properties. For the parameters that are identified as being most-influential, recommended values for these parameters are suggested in conceptual terms that are conducive to designing composite sandwich panels for various blast threats. Based on reviewing the energy response characteristic of the panel under blast loading, a non-dimensional parameter AET/ ET (absorbed energy, AET, normalized by total energy

  11. Mechanical evaluation with fe analysis of sandwich panels for wind turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Yasaswi, M.; Naveen, P.N.E.; Prasad, R.V. [GIET. Dept. of Mechanical Engineering, Rajahmundry (India)

    2012-07-01

    Sandwich panels are notable for their structural efficiency and are used as load bearing components in various branches of engineering, especially in aerospace and marine industries. The objective of the present work is to perform computer-aided analysis on sandwich panels. The analysis of sandwich panel with truss core are compared with other four types of sandwich panel with continuous corrugated core, top hat core, zed core and channel core. The basic reason to use sandwich structure is to save weight, however smooth skins and excellent fatigue resistance are also attributes of a sandwich structure. A sandwich is comprised of two layered composite materials formed by bonding two or more thin facings or face sheets to relatively thick core materials. In this type of construction the facings resist nearly all of the in-plane loads and out-of-plane bending moments. The thin facings provide nearly all of the bending stiffness because they are generally of a much higher modulus material is located at a greatest distance from the neutral axis of the component. The basic concept of sandwich panel is that the facings carry the bending loads and the core carries the shear loads. The main function of the core material is to distribute local loads and stresses over large areas. From all this analysis it is concluded that the truss core Sandwich panels can be used in wind turbine blade design. (Author)

  12. Combined-load buckling behavior of metal-matrix composite sandwich panels under different thermal environments

    Science.gov (United States)

    Ko, William L.; Jackson, Raymond H.

    1991-01-01

    Combined compressive and shear buckling analysis was conducted on flat rectangular sandwich panels with the consideration of transverse shear effects of the core. The sandwich panel is fabricated with titanium honeycomb core and laminated metal matrix composite face sheets. The results show that the square panel has the highest combined load buckling strength, and that the buckling strength decreases sharply with the increases of both temperature and panel aspect ratio. The effect of layup (fiber orientation) on the buckling strength of the panels was studied in detail. The metal matrix composite sandwich panel was much more efficient than the sandwich panel with nonreinforced face sheets and had the same specific weight.

  13. 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.

  14. Sandwich Hologram Interferometry For Determination Of Sacroiliac Joint Movements

    Science.gov (United States)

    Vukicevic, S.; Vinter, I.; Vukicevic, D.

    1983-12-01

    Investigations were carried out on embalmed and fresh specimens of human pelvisis with preserved lumbar spines, hip joints and all the ligaments. Specimens were tested under static vertical loading by pulsed laser interferometry. The deformations and behaviour of particular pelvic parts were interpreted by providing computer interferogram models. Results indicate rotation and tilting of the sacrum in the dorso-ventral direction and small but significant movements in the cranio-caudal direction. Sandwich holography proved to be the only applicable method when there is a combination of translation and tilt in the range of 200 μm to 1.5 mm.

  15. Magnetic-property changes in epitaxial metal-film sandwiches

    International Nuclear Information System (INIS)

    Brodsky, M.B.

    1982-08-01

    Epitaxial metal-film sandwiches (EMFS) containing Pd or Cr, have been prepared between single-crystal Ag or Au. The modified Pd/Cr show major changes in physical properties. Pd has a stretched lattice parameter in Au-Pd-Au, which combines with a tetragonal distortion to cause exchange enhancements up to 28,000 and spin-fluctuation temperatures of 1 to 10 K. In Au-Cr-Au, Cr takes up the fcc structure, leading to superconductivity due to a high N(E/sub F/). These results are contrasted to data for Ag-Pd-Ag and Ag-Cr-Ag EMFS

  16. FINITE ELEMENT MODELING OF THIN CIRCULAR SANDWICH PLATES DEFLECTION

    Directory of Open Access Journals (Sweden)

    K. S. Kurachka

    2014-01-01

    Full Text Available A mathematical model of a thin circular sandwich plate being under the vertical load is proposed. The model employs the finite element method and takes advantage of an axisymmetric finite element that leads to the small dimension of the resulting stiffness matrix and sufficient accuracy for practical calculations. The analytical expressions for computing local stiffness matrices are found, which can significantly speed up the process of forming the global stiffness matrix and increase the accuracy of calculations. A software is under development and verification. The discrepancy between the results of the mathematical model and those of analytical formulas for homogeneous thin circularsandwich plates does not exceed 7%.

  17. Residual Strength Prediction of Debond Damaged Sandwich Panels

    DEFF Research Database (Denmark)

    Berggreen, Carl Christian

    followed by debond growth. The developed theoretical procedure is an extension of the Crack Surface Displacement method, here denoted the Crack Surface Displacement Extrapolation method. The method is first developed in 2D and then extended to 3D by use of a number of realistic assumptions...... for the considered configurations. Comparison of the theoretical predictions to two series of large-scale experiments with loadings (uniform and non-uniform in-plane compression) comparable with real life loading scenarios for sandwich ships shows that the model is indeed able to predict the failure modes...

  18. Buckling analysis of laminated sandwich beam with soft core

    Directory of Open Access Journals (Sweden)

    Anupam Chakrabarti

    Full Text Available Stability analysis of laminated soft core sandwich beam has been studied by a C0 FE model developed by the authors based on higher order zigzag theory (HOZT. The in-plane displacement variation is considered to be cubic for the face sheets and the core, while transverse displacement is quadratic within the core and constant in the faces beyond the core. The proposed model satisfies the condition of stress continuity at the layer interfaces and the zero stress condition at the top and bottom of the beam for transverse shear. Numerical examples are presented to illustrate the accuracy of the present model.

  19. Precast concrete sandwich panels subjected to impact loading

    Science.gov (United States)

    Runge, Matthew W.

    Precast concrete sandwich panels are a relatively new product in the construction industry. The design of these panels incorporates properties that allow for great resilience against temperature fluctuation as well as the very rapid and precise construction of facilities. The concrete sandwich panels investigated in this study represent the second generation of an ongoing research and development project. This second generation of panels have been engineered to construct midsized commercial buildings up to three stories in height as well as residential dwellings. The panels consist of a double-tee structural wythe, a foam core and a fascia wythe, joined by shear connectors. Structures constructed from these panels may be subjected to extreme loading including the effects of seismic and blast loading in addition to wind. The aim of this work was to investigate the behaviour of this particular sandwich panel when subjected to structural impact events. The experimental program consisted of fourteen concrete sandwich panels, five of which were considered full-sized specimens (2700 mm X 1200mm X 270 mm) and nine half-sized specimens (2700mm X 600mm X 270 mm) The panels were subjected to impact loads from a pendulum impact hammer where the total energy applied to the panels was varied by changing the mass of the hammer. The applied loads, displacements, accelerations, and strains at the mid-span of the panel as well as the reaction point forces were monitored during the impact. The behaviour of the panels was determined primarily from the experimental results. The applied loads at low energy levels that caused little to no residual deflection as well as the applied loads at high energy levels that represent catastrophic events and thus caused immediate failure were determined from an impact on the structural and the fascia wythes. Applied loads at intermediate energy levels representing extreme events were also used to determine whether or not the panels could withstand

  20. Development and Validation of an ELISA at Acidic pH for the Quantitative Determination of IL-13 in Human Plasma and Serum

    Directory of Open Access Journals (Sweden)

    Julie Doucet

    2013-01-01

    Full Text Available A novel sandwich ELISA for the quantitative and sensitive determination of IL-13 in human serum and plasma was established. The assay employs an incubation step at acidic pH, which was shown to decrease nonspecific binding and interference from IL-13 binding proteins. The assay was validated and was shown to be accurate and precise over the entire quantification range (0.59 to 68.4 pg/mL in human EDTA plasma. The validated assay was successfully applied to samples from healthy volunteers and patients with atopic seasonal rhinitis. The assay is suitable for use in clinical trials to monitor efficacy or pharmacodynamic effects of drug candidates.

  1. 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.

  2. Ultrasensitive and accelerated detection of ciguatoxin by capillary electrophoresis via on-line sandwich immunoassay with rotating magnetic field and nanoparticles signal enhancement.

    Science.gov (United States)

    Zhang, Zhaoxiang; Zhang, Chaoying; Luan, Wenxiu; Li, Xiufeng; Liu, Ying; Luo, Xiliang

    2015-08-12

    A sensitive and rapid on-line immunoassay for the determination of ciguatoxin CTX3C was developed based on a capillary mixing system, which was integrated with capillary electrophoresis (CE) separation and electrochemical (EC) detection. In the sandwich immunoassay system, anti-CTX3C-functionalized magnetic nanoparticles were used as immunosensing probes, and horseradish peroxidase (HRP) and anti-CTX3C antibody were bound onto the surface of gold nanoparticles (AuNPs) and used as recognition elements. Online formation of immunocomplex was realized in capillary inlet end with an external rotating magnetic field. Compared with classical HPLC-MS and ELISA, the assay adopting AuNPs as multienzyme carriers and online sandwich immunoassay format with rotating magnetic field exhibited higher sensitivity and shorter assay time. The linear range of the assay for CTX3C was from 0.6 to 150 ng/L with a correlation coefficient of 0.9948 (n = 2), and the detection limit (S/N = 3) was 0.09 ng/L. The developed assay showed satisfying reproducibility and stability, and it was successfully applied for the quantification of CTX3C in fish samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Active structural health monitoring of composite plates and sandwiches

    Directory of Open Access Journals (Sweden)

    Sadílek P.

    2013-12-01

    Full Text Available The aim of presented work is to design, assemble and test a functional system, that is able to reveal damage from impact loading. This is done by monitoring of change of spectral characteristics on a damaged structure that is caused by change of mechanical properties of material or by change of structure’s geometry. Excitation and monitoring of structures was done using piezoelectric patches. Unidirectional composite plate was tested for eigenfrequencies using chirp signal. The eigenfrequencies were compared to results from experiments with an impact hammer and consequently with results from finite element method. Same method of finding eigenfrequencies was used on a different unidirectional composite specimen. Series of impacts were performed. Spectrum of eigenfrequencies was measured on undamaged plate and then after each impact. Measurements of the plate with different level of damage were compared. Following experiments were performed on sandwich materials where more different failures may happen. Set of sandwich beams (cut out from one plate made of two outer composite layers and a foam core was investigated and subjected to several impacts. Several samples were impacted in the same manner to get comparable results. The impacts were performed with growing impact energy.

  4. Efficacy demonstration of tetanus vaccines by double antigen ELISA.

    Science.gov (United States)

    Rosskopf, U; Noeske, K; Werner, E

    2005-09-01

    This paper describes a double antigen ELISA (DAE) for rapid, specific and reliable assessment of the antitetanus immune status of horses and sheep. Compared with the indirect ELISA, the double antigen ELISA has the advantage of species-independent testing of sera. Thanks to its test design, it is more specific since the detected antibodies are forced to bind tetanus toxoid twice. In addition, it is very sensitive to tetanus antibodies, enabling the detection of low antibody titres, in range which is relevant for the assessment of the protective status (tetanus toxin neutralising antibodies). The detection limit of the DAE for tetanus antibodies is in the order of 10(-4) EU/ml. A comparison of in vitro results of individual sera with in vivo titres showed that horse sera with titres of 0.04 and 0.05 EU/ml in the DAE showed titres of > 0.05 IU and 0.034 IU/ml respectively during in vivo testing thus indicating good agreement. For tested sheep sera which were rated > 0.05 IU/ml in vivo, the corresponding titre in the DAE was 0.24 EU/ml. Clear tetanus antitoxin establishment of protective ELISA limits requires further comparative examination of sera with low titres (tetanus vaccines ad us. vet. As a consequence, the toxin neutralisation test (still being the standard method of choice for quantifying tetanus toxin neutralising antitoxin titres) could be replaced, since it requires too great a number of animals per test and involves considerable suffering for the animals. The test described here reduces the use of mice and guinea pigs within vaccine efficacy testing. In addition, it involves less exposure of the laboratory personnel to toxin.

  5. Purification, characterization and ELISA detection of mink immunoglobulins

    DEFF Research Database (Denmark)

    Martel, Cyril Jean-Marie; Aasted, Bent

    2008-01-01

    the estimated molecular weights of the immunoglobulin gamma, alpha and mu heavy chains were found to be 54 kDa, 69 kDa and 83 kDa respectively. The purities of purified IgG, IgM and IgA were estimated by immunoglobulin class specific ELISAs to be more than 90% for IgG and IgM, and more than 80% for IgA....

  6. ELISA techniques for the determination of methanogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bryniok, D; Troesch, W [Fraunhofer-Institut fuer Grenzflaechen- und Bioverfahrenstechnik (IGB), Stuttgart (Germany, F.R.)

    1989-12-01

    Easy-to-handle enzyme-linked immunosorbent assay (ELISA) techniques have been developed suitable for quantitative species-specific determination of very low numbers of methanogens in complex bacterial populations. The amount and the distribution of different species of methanogens in anaerobic digestors is a reflection of the functional status of the degradation process; this can be recognized with these tests and hence may be used for process control. (orig.).

  7. Laser welded steel sandwich panel bridge deck development : finite element analysis and stake weld strength tests.

    Science.gov (United States)

    2009-09-01

    This report summarizes the analysis of laser welded steel sandwich panels for use in bridge structures and : static testing of laser stake welded lap shear coupons. Steel sandwich panels consist of two face sheets : connected by a relatively low-dens...

  8. 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.

  9. The Effect of Face Sheet Wrinkle Defects on the Strength of FRP Sandwich Structures

    DEFF Research Database (Denmark)

    Hayman, Brian; Berggreen, Christian; Pettersson, Robert

    2007-01-01

    . In the studies reported here, the influence of wrinkle defects on the in-plane compressive strength of quasi-isotropic carbon fiber reinforced plastic (CFRP) laminates used in PVC foam-cored sandwich panels has been investigated by three approaches: testing of sandwich beam specimens in four-point bending...

  10. Failure of uniformly compression loaded debond damaged sandwich panels — An experimental and numerical study

    DEFF Research Database (Denmark)

    Moslemian, Ramin; Quispitupa, Amilcar; Berggreen, Christian

    2012-01-01

    This paper deals with the failure of compression-loaded sandwich panels with an implanted circular face/core debond. Uniform compression tests were conducted on intact sandwich panels with three different types of core material (H130, H250 and PMI) and on similar panels with circular face...

  11. Failure Investigation of Debonded Sandwich Columns: An Experimental and Numerical Study

    DEFF Research Database (Denmark)

    Moslemian, Ramin; Berggreen, Christian; Carlsson, Leif A.

    2009-01-01

    Failure of compression loaded sandwich columns with an implanted through-width face/core debond is examined. Compression tests were conducted on sandwich columns containing implemented face/core debonds. The strains and out-of-plane displacements of the debonded region were monitored using the di...

  12. Functional grading of metal foam cores for yield-limited lightweight sandwich beams

    International Nuclear Information System (INIS)

    Conde, Yves; Pollien, Arnaud; Mortensen, Andreas

    2006-01-01

    We show that grading the porosity in a bent metal skin/metal foam core sandwich can generate significant weight savings in yield-limited design when, and only when, there is a gradient in the applied moment along the sandwich beam

  13. Influence of affinity on antibody determination in microtiter ELISA systems

    International Nuclear Information System (INIS)

    Peterman, J.H.; Voss, E.W. Jr.; Butler, J.E.

    1986-01-01

    Theoretically, all immunoassays are affinity (Ka) dependent when the product of the antibody (Ab) Ka and the free epitope concentration is less than 10. Thus, the degree of dependence on Ka depends on the concentration of available antigen in the system. The authors examined the binding of 125 I-anti-fluorescein (a-FLU) monoclonal antibodies of different affinities to FLU-gelatin adsorbed on Immunlon 2 microtiter plates. Data obtained were in general agreement with our theoretical predictions; the percent of 125 I-a-FLU which bound correlated with Ka, as did the shape of the titration curves. Measurement of 5 a-FLU monoclonals by the ELISA showed that the determination of Ab concentrations depends on the FLU-gelatin concentration, epitope density, and on the relationship between the Kas of test samples and the reference standard Ab preparation. Thus the ELISA is Ka dependent and should not be used routinely to estimate the absolute amount to Ab in unknown samples. However, the Ka dependency of the ELISA might provide a convenient assay for the estimation of the relative functional Ka (rfKa) of antibody preparations

  14. Indirect Competitive Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Kohl, Thomas O; Ascoli, Carl A

    2017-07-05

    The indirect competitive ELISA (indirect cELISA) pits plate-immobilized antigen against antigens in solution for binding to antigen-specific antibody. The antigens in solution are in the test sample and are first incubated with antigen-specific antibody. These antibody-antigen complexes are then added to microtiter plates whose wells have been coated with purified antigen. The wells are washed to remove unbound antigen-antibody complexes and free antigen. A reporter-labeled secondary antibody is then added followed by the addition of substrate. Substrate hydrolysis yields a signal that is inversely proportional to antigen concentration within the sample. This is because when antigen concentration is high in the test sample, most of the antibody is bound before adding the solution to the plate. Most of the antibody remains in solution (as complexes) and is thus washed away before the addition of the reporter-labeled secondary antibody and substrate. Thus, the higher the antigen concentration in the test sample, the weaker the resultant signal in the detection step. The indirect cELISA is often used for competitive detection and quantification of antibodies against viral diseases in biological samples. © 2017 Cold Spring Harbor Laboratory Press.

  15. Development and application of an antibody-based protein microarray to assess physiological stress in grizzly bears (Ursus arctos).

    Science.gov (United States)

    Carlson, Ruth I; Cattet, Marc R L; Sarauer, Bryan L; Nielsen, Scott E; Boulanger, John; Stenhouse, Gordon B; Janz, David M

    2016-01-01

    A novel antibody-based protein microarray was developed that simultaneously determines expression of 31 stress-associated proteins in skin samples collected from free-ranging grizzly bears (Ursus arctos) in Alberta, Canada. The microarray determines proteins belonging to four broad functional categories associated with stress physiology: hypothalamic-pituitary-adrenal axis proteins, apoptosis/cell cycle proteins, cellular stress/proteotoxicity proteins and oxidative stress/inflammation proteins. Small skin samples (50-100 mg) were collected from captured bears using biopsy punches. Proteins were isolated and labelled with fluorescent dyes, with labelled protein homogenates loaded onto microarrays to hybridize with antibodies. Relative protein expression was determined by comparison with a pooled standard skin sample. The assay was sensitive, requiring 80 µg of protein per sample to be run in triplicate on the microarray. Intra-array and inter-array coefficients of variation for individual proteins were generally bears. This suggests that remotely delivered biopsy darts could be used in future sampling. Using generalized linear mixed models, certain proteins within each functional category demonstrated altered expression with respect to differences in year, season, geographical sampling location within Alberta and bear biological parameters, suggesting that these general variables may influence expression of specific proteins in the microarray. Our goal is to apply the protein microarray as a conservation physiology tool that can detect, evaluate and monitor physiological stress in grizzly bears and other species at risk over time in response to environmental change.

  16. Antibody-based enzyme-linked lectin assay (ABELLA) for the sialylated recombinant human erythropoietin present in culture supernatant.

    Science.gov (United States)

    Kim, Hyoung Jin; Lee, Seung Jae; Kim, Hong-Jin

    2008-11-04

    The terminal sialic acid of human erythropoietin (hEPO) is essential for in vivo activity. The current resorcinol and HPLC methods for analyzing alpha2,3-linked sialic acid require more than a microgram of purified rhEPO, and purification takes a great deal of time and labor. In this study, we assessed the use of an antibody-based enzyme-linked lectin assay (ABELLA) for analyzing non-purified recombinant hEPO (rhEPO). The major problem of this method was the high background due to terminal sialylation of components of the assay (antibody and bovine serum albumin) other than rhEPO. To solve this problem, we used a monoclonal antibody (Mab 287) to capture the rhEPO, and oxidized the bovine serum albumin used for blocking with meta-periodate. The sialic acid content of non-purified rhEPO measured by ABELLA was similar to that obtained by the resorcinol method on purified rhEPO. ABELLA has advantages such as adaptability and need for minimal amounts of rhEPO (40 ng/ml). Our observations suggest that ABELLA should reduce the time and labor needed to improve culture conditions so as to increase protein sialylation, and also facilitate the study of sialylation mechanisms.

  17. Antibody-based PET of uPA/uPAR signaling with broad applicability for cancer imaging

    DEFF Research Database (Denmark)

    Yang, Dongzhi; Severin, Gregory; Dougherty, Casey A.

    2016-01-01

    Mounting evidence suggests that the urokinase plasminogen activator (uPA) and its receptor (uPAR) play a central role in tumor progression. The goal of this study was to develop an 89Zr-labeled, antibody-based positron emission tomography (PET) tracer for quantitative imaging of the uPA/uPAR system....... An anti-uPA monoclonal antibody (ATN-291) was conjugated with a deferoxamine (Df) derivative and subsequently labeled with 89Zr. Flow cytometry, microscopy studies, and competitive binding assays were conducted to validate the binding specificity of Df-ATN-291 against uPA. PET imaging with 89Zr-Df-ATN-291...... was carried out in different tumors with distinct expression levels of uPA. Biodistribution, histology examination, and Western blotting were performed to correlate tumor uptake with uPA or uPAR expression. ATN-291 retained uPA binding affinity and specificity after Df conjugation. 89Zr-labeling of ATN-291...

  18. Behavior of composite sandwich panels with several core designs at different impact velocities

    Science.gov (United States)

    Jiga, Gabriel; Stamin, Ştefan; Dinu, Gabriela

    2018-02-01

    A sandwich composite represents a special class of composite materials that is manufactured by bonding two thin but stiff faces to a low density and low strength but thick core. The distance between the skins given by the core increases the flexural modulus of the panel with a low mass increase, producing an efficient structure able to resist at flexural and buckling loads. The strength of sandwich panels depends on the size of the panel, skins material and number or density of the cells within it. Sandwich composites are used widely in several industries, such as aerospace, automotive, medical and leisure industries. The behavior of composite sandwich panels with different core designs under different impact velocities are analyzed in this paper by numerical simulations performed on sandwich panels. The modeling was done in ANSYS and the analysis was performed through LS-DYNA.

  19. Analysis and Behaviour of Sandwich Panels with Profiled Metal Facings under Transverse Load

    Directory of Open Access Journals (Sweden)

    M. Budescu

    2004-01-01

    Full Text Available Sandwich panels with thin steel facings and polyurethane core combine the load-carrying capacity of metal facings and protection functions with core properties. The core separates the two facings and keeps them in a stable condition, transmits shear between external layers, provides most of the shear rigidity and occasionally makes of useful contribution to the bending stiffness of the sandwich construction as a whole [1]. An experimental program on sandwich panels has been organized to prove that the mechanical properties of core and interface satisfy the load-carrying requirements for structural sandwich panels. The analysis of sandwich panels with deep profiles facings for cladding elements, respectively the roof constructions, has been carried out according to the European design norms [1], [5].

  20. Natural cork agglomerate employed as an environmentally friendly solution for quiet sandwich composites.

    Science.gov (United States)

    Sargianis, James; Kim, Hyung-ick; Suhr, Jonghwan

    2012-01-01

    Carbon fiber-synthetic foam core sandwich composites are widely used for many structural applications due to their superior mechanical performance and low weight. Unfortunately these structures typically have very poor acoustic performance. There is increasingly growing demand in mitigating this noise issue in sandwich composite structures. This study shows that marrying carbon fiber composites with natural cork in a sandwich structure provides a synergistic effect yielding a noise-free sandwich composite structure without the sacrifice of mechanical performance or weight. Moreover the cork-core sandwich composites boast a 250% improvement in damping performance, providing increased durability and lifetime operation. Additionally as the world seeks environmentally friendly materials, the harvesting of cork is a natural, renewable process which reduces subsequent carbon footprints. Such a transition from synthetic foam cores to natural cork cores could provide unprecedented improvements in acoustic and vibrational performance in applications such as aircraft cabins or wind turbine blades.

  1. High renewable content sandwich structures based on flax-basalt hybrids and biobased epoxy polymers

    Science.gov (United States)

    Colomina, S.; Boronat, T.; Fenollar, O.; Sánchez-Nacher, L.; Balart, R.

    2014-05-01

    In the last years, a growing interest in the development of high environmental efficiency materials has been detected and this situation is more accentuated in the field of polymers and polymer composites. In this work, green composite sandwich structures with high renewable content have been developed with core cork materials. The base resin for composites was a biobased epoxy resin derived from epoxidized vegetable oils. Hybrid basalt-flax fabrics have been used as reinforcements for composites and the influence of the stacking sequence has been evaluated in order to optimize the appropriate laminate structure for the sandwich bases. Core cork materials with different thickness have been used to evaluate performance of sandwich structures thus leading to high renewable content composite sandwich structures. Results show that position of basalt fabrics plays a key role in flexural fracture of sandwich structures due to differences in stiffness between flax and basalt fibers.

  2. Modification the ELISA Kit for diagnosis of “Pseudomonas aeruginosa and comparing it with ordinary ELISA kit”

    Directory of Open Access Journals (Sweden)

    Taghreed A. Mohammad

    2017-07-01

    Full Text Available The first aim of the present study was to diagnosis Pseudomonas  aeruginosa by many tests. This study consisted "200 patients " who suffered from burn wound and compare with 100 health individuals (male and female as a control group, Vitek test was used to diagnose  118 (87 "local isolate  ATCC 15692" with 31 other isolate of Pseudomonas  aeruginosa  ((ATCC 15690, ATCC 15688  from 200 samples which were taken from burn patients. This result was similar to Analytical profile index ( API   test (118 isolates of  P. aeruginosa with 82 isolations of  other bacteria. Then the detection P. aeruginosa isolate  ATCC 15692 by new ELISA Technique and comparing its with modify the ordinary ELISA kit.

  3. A noise simulator for eLISA: Migrating LISA Pathfinder knowledge to the eLISA mission

    OpenAIRE

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, Michael; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, Karsten; Diepholz, I.

    2015-01-01

    We present a new technical simulator for the eLISA mission, based on state space modeling techniques and developed in MATLAB. This simulator computes the coordinate and velocity over time of each body involved in the constellation, i.e. the spacecraft and its test masses, taking into account the different disturbances and actuations. This allows studying the contribution of instrumental noises and system imperfections on the residual acceleration applied on the TMs, the latter reflecting the ...

  4. Development of a Blocking ELISA Using a Monoclonal Antibody to a Dominant Epitope in Non-Structural Protein 3A of Foot-and-Mouth Disease Virus, as a Matching Test for a Negative-Marker Vaccine.

    Directory of Open Access Journals (Sweden)

    Yuanfang Fu

    Full Text Available Foot-and-mouth disease (FMD is a devastating animal disease. Strategies for differentiation of infected from vaccinated animals (DIVA remain very important for controlling disease. Development of an epitope-deleted marker vaccine and accompanying diagnostic method will improve the efficiency of DIVA. Here, a monoclonal antibody (Mab was found to recognize a conserved "AEKNPLE" epitope spanning amino acids 109-115 of non-structural protein (NSP 3A of foot-and-mouth disease virus (FMDV; O/Tibet/CHA/99 strain, which could be deleted by a reverse-genetic procedure. In addition, a blocking ELISA was developed based on this Mab against NSP 3A, which could serve as a matching test for a negative-marker vaccine. The criterion of this blocking ELISA was determined by detecting panels of sera from different origins. The serum samples with a percentage inhibition (PI equal or greater than 50% were considered to be from infected animals, and those with <50% PI were considered to be from non-infected animals. This test showed similar performance when compared with other 2 blocking ELISAs based on an anti-NSP 3B Mab. This is the first report of the DIVA test for an NSP antibody based on an Mab against the conserved and predominant "AEKNPLE" epitope in NSP 3A of FMDV.

  5. Assessment of the repeatability and border-plate effects of the B158/B60 enzyme-linked-immunosorbent assay for the detection of circulating antigens (Ag-ELISA) of Taenia saginata.

    Science.gov (United States)

    Jansen, Famke; Dorny, Pierre; Berkvens, Dirk; Van Hul, Anke; Van den Broeck, Nick; Makay, Caroline; Praet, Nicolas; Gabriël, Sarah

    2016-08-30

    The monoclonal antibody-based circulating antigen detecting ELISA (B158/B60 Ag-ELISA) has been used elaborately in several studies for the diagnosis of human, bovine and porcine cysticercosis. Interpretation of test results requires a good knowledge of the test characteristics, including the repeatability and the effect of the borders of the ELISA plates. Repeatability was tested for 4 antigen-negative and 5 antigen-positive reference bovine serum samples by calculating the Percentage Coefficient of Variation (%CV) within and between plates, within and between runs, overall, for two batches of monoclonal antibodies and by 2 laboratory technicians. All CV values obtained were below 20% (except one: 24.45%), which indicates a good repeatability and a negligible technician error. The value of 24.45% for indicating the variability between batches of monoclonal antibodies for one positive sample is still acceptable for repeatability measures. Border effects were determined by calculating the %CV values between the inner and outer wells of one plate for 2 positive serum samples. Variability is a little more present in the outer wells but this effect is very small and no significant border effect was found. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Methodology for determination of plasma cortisol in fish using Competitive Enzyme-Linked Immunosorbent Assay (ELISA)

    DEFF Research Database (Denmark)

    Velasco-Santamaría, Yohana M.; Cruz-Casallas, Pablo E.

    2007-01-01

    Objective. To determine plasma cortisol procedure in fish using competitive enzymelinked immunosorbent assay (ELISA). Materials and methods. Two plasma samples of juveniles rainbow trout Oncorhynchus mykiss were analized by using ELISA human kit for cortisol assay. For standard curve calibration...

  7. Morphology Analysis of Cu Film Fractures in Sandwiched Methylmethacrylate Plates

    Directory of Open Access Journals (Sweden)

    Cristiano Fidani

    2015-06-01

    Full Text Available Thin films of Cu were evaporated on solid plates of polymethylmethacrylate (PMMA. A polymerization process was made to realize sandwiched structure to protect the Cu films. Fracturing of the metal film surface was observed with several morphologies showing two different fracture systems. Surface film morphology was analysed in terms of the distribution area of the islands and contour fractal dimension. The island areas showed a maximum corresponding to 42 nm of the Cu thickness, it was also the threshold to observe the second fracture system. The fractures pattern resulted to be scale invariant with fractal dimensions between 1.55 and 1.7. The minimum fractal dimension also occurred at the film thickness corresponding to the maximum island area. The reported effects can be understood on the basis of different thermal expansion coefficients of the two materials and their thermally induced adhesion.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.6518

  8. Vibration Control of Sandwich Beams Using Electro-Rheological Fluids

    Science.gov (United States)

    Srikantha Phani, A.; Venkatraman, K.

    2003-09-01

    Electro-rheological (ER) fluids are a class of smart materials exhibiting significant reversible changes in their rheological and hence mechanical properties under the influence of an applied electric field. Efforts are in progress to embed ER fluids in various structural elements to mitigate vibration problems. The present work is an experimental investigation of the behaviour of a sandwich beam with ER fluid acting as the core material. A starch-silicone-oil-based ER fluid is used in the present study. Significant improvements in the damping properties are achieved in experiments and the damping contributions by viscous and non-viscous forces are estimated by force-state mapping (FSM) technique. With the increase in electric field across the ER fluid from 0 to 2 kV, an increase of 25-50% in equivalent viscous damping is observed. It is observed that as concentration of starch is increased, the ER effect grows stronger but eventually is overcome by applied stresses.

  9. 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-alpha...... (TNF-alpha). The accuracy of each of the assays was evaluated in the ranges of 1-15 microg/l (IL-4), 0.001-1 microg/l (IL-5), 0.5-2.5 microg/l (IFN-T) and 0.14-2.2 microg/l (TNF-alpha). Other evaluated performance characteristics were the limit of detection (LOD), immunological specificity......) 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...

  10. Rapid enzyme-linked immunosorbent assay (ELISA) for Aspergillus fumigatus antibodies.

    OpenAIRE

    Richardson, M D; Stubbins, J M; Warnock, D W

    1982-01-01

    A rapid enzyme-linked immunosorbent assay (ELISA) where component incubation periods were shortened to one hour, was compared with agar gel double diffusion (AGDD) and a standard ELISA procedure for detecting antibodies to Aspergillus fumigatus in 28 asthmatic patients with suspected allergic aspergillosis. Using two A fumigatus antigens the rapid ELISA compared well with AGDD and the standard ELISA method. Eleven sera that reacted with both antigens in AGDD were all positive against antigen ...

  11. Detection of toxoplasma-specific immunoglobulin G in human sera: performance comparison of in house Dot-ELISA with ECLIA and ELISA.

    Science.gov (United States)

    Teimouri, Aref; Modarressi, Mohammad Hossein; Shojaee, Saeedeh; Mohebali, Mehdi; Zouei, Nima; Rezaian, Mostafa; Keshavarz, Hossein

    2018-05-08

    In the current study, performance of electrochemiluminescence immunoassay (ECLIA) in detection of anti-toxoplasma IgG in human sera was compared with that of enzyme-linked immunosorbent assay (ELISA). Furthermore, performance of an in house Dot-ELISA in detection of anti-toxoplasma IgG was compared with that of ECLIA and ELISA. In total, 219 human sera were tested to detect anti-toxoplasma IgG using Dynex DS2® and Roche Cobas® e411 Automated Analyzers. Discordant results rechecked using immunofluorescence assay (IFA). Then, sera were used in an in house Dot-ELISA to assess toxoplasma-specific IgG. Of the 219 samples, two samples were found undetermined using ECLIA but reactive using ELISA. Using IFA, the two sera were reported unreactive. Furthermore, two samples were found reactive using ECLIA and unreactive using ELISA. These samples were reported reactive using IFA. The overall agreement for the two former methods was 98% (rZ0.98.1; P house Dot-ELISA included sensitivity of 79.5, specificity of 78.2, and accuracy of 78.9%, compared to ECLIA and ELISA. Positive and negative predictive values included 82.9 and 74.2%, respectively. A 100% sensitivity was found in in house Dot-ELISA for highly reactive sera in ECLIA and ELISA. ECLIA is appropriate for the first-line serological screening tests and can replace ELISA due to high speed, sensitivity, and specificity, particularly in large laboratories. Dot-ELISA is a rapid, sensitive, specific, cost-effective, user-friendly, and field-portable technique and hence can be used for screening toxoplasmosis, especially in rural fields or less equipped laboratories.

  12. Comparison of DOT-ELISA and Standard-ELISA for Detection of the Vibrio cholerae Toxin in Culture Supernatants of Bacteria Isolated from Human and Environmental Samples.

    Science.gov (United States)

    Meza-Lucas, Antonio; Pérez-Villagómez, María-Fernanda; Martínez-López, José-Patricio; García-Rodea, Ricardo; Martínez-Castelán, María-Guadalupe; Escobar-Gutiérrez, Alejandro; de-la-Rosa-Arana, Jorge-Luis; Villanueva-Zamudio, Altagracia

    2016-09-01

    A comparison of DOT-ELISA and Standard-ELISA was made for detection of Vibrio cholerae toxin in culture supernatants of bacteria isolated from human and environmental samples. A total of 293 supernatants were tested in a double blind assay. A correlation of 100 % was obtained between both techniques. The cholera toxin was found in 20 Inaba and 3 Ogawa strains. Positive samples were from seafood (17 samples), potable water (1 sample) and sewage (5 samples). The DOT-ELISA was useful as the standard-ELISA to confirm the presence of cholera toxin in the environmental samples.

  13. The Diagnostic Value of ELISA Method for Pertussis in Children

    Directory of Open Access Journals (Sweden)

    O. P. Popova

    2016-01-01

    Full Text Available Because of low effectiveness of laboratory methods for diagnosing pertussis it is important to look for new ways of verification of this infection. The article presents the analysis of the diagnostic value of ELISA method, which involves the identification of antibodies of different isotypes (IgM, IgG, IgA to pertussis toxoid (PT and filamentous haemagglutinin (FHA. The study included 279 children: 114 were under 1 year of age, 165 — older than 1 year. The pertussis was confirmed in 74.3 ± 2.6% of patients by using ELISA method. A significant proportion of seronegative patients (46.1 ± 6.2 per cent was revealed in the group of patients under 1 year. The pattern of production of antibodies in unvaccinated children was different. It depended on the age of the children and timing of illness. A low proportion of diagnostically significant indicators of IgM-antibodies at 2—3 weeks of illness was typical for patients under 1 year of age (e.g. 6.7 ± 6.5% as compared to 20.0 ± 7.9% and 50.0 ± 15.3 — 1—3 and 4—6 years of age. The diagnosis of pertussis in children under 1 year of age was confirmed mainly by the detection of IgG, starting from the 4th week of the disease. In the examination of vaccinated children diagnostically significant levels of IgA and IgG were identified (even in the late stages of the disease. Thus, the results of the analysis show special significance of using ELISA method for the diagnosis of pertussis in vaccinated children.

  14. Numerical Study on the Projectile Impact Resistance of Multi-Layer Sandwich Panels with Cellular Cores

    Directory of Open Access Journals (Sweden)

    Liming Chen

    Full Text Available Abstract The projectile impact resistance of sandwich panels with cellular cores with different layer numbers has been numerically investigated by perpendicular impact of rigid blunt projectile in ABAQUS/Explicit. These panels with corrugation, hexagonal honeycomb and pyramidal truss cores are impacted at velocities between 50 m/s and 202 m/s while the relative density ranges from 0.001 to 0.15 The effects of core configuration and layer number on projectile impact resistance of sandwich panels with cellular cores are studied. At low impact velocity, sandwich panels with cellular cores outperform the corresponding solid ones and non-montonicity between relative density and projectile resistance of sandwich panels is found and analyzed. Multiplying layer can reduce the maximum central deflection of back face sheet of the above three sandwich panels except pyramidal truss ones in high relative density. Hexagonal honeycomb sandwich panel is beneficial to increasing layer numbers in lowering the contact force and prolonging the interaction time. At high impact velocity, though corrugation and honeycomb sandwich panels are inferior to the equal-weighted solid panels, pyramidal truss ones with high relative density outperform the corresponding solid panels. Multiplying layer is not the desirable way to improve high-velocity projectile resistance.

  15. Behaviour of glued fibre composite sandwich structure in flexure: Experiment and Fibre Model Analysis

    International Nuclear Information System (INIS)

    Manalo, Allan; Aravinthan, Thiru

    2012-01-01

    Highlights: ► Fibre Model Analysis is used to examine the flexural behaviour of sandwich beams. ► Theoretical prediction using FMA is in good agreement with the experiment. ► Using the constituent materials in FMA predicted accurately the beam’s behaviour. ► FMA can be used for analysing sandwich beams with high-strength core in flexure. -- Abstract: The behaviour of glued composite sandwich beams in flexure was investigated with a view of using this material for structural and civil engineering applications. The building block of this glue-laminated beam is a new generation composite sandwich structure made up of glass fibre reinforced polymer skins and a high strength phenolic core material. A simplified Fibre Model Analysis (FMA) usually used to analyse a concrete beam section is adopted to theoretically describe the flexural behaviour of the innovative sandwich beam structure. The analysis included the flexural behaviour of the glued sandwich beams in the flatwise and the edgewise positions. The FMA accounted for the non-linear behaviour of the phenolic core in compression, the cracking of the core in tension and the linear elastic behaviour of the fibre composite skin. The results of the FMA showed a good agreement with the experimental data showing the efficiency and practical applications of the simplified FMA in analysing and designing sandwich structures with high strength core material.

  16. Experimental study of the mechanical behaviour of pin reinforced foam core sandwich materials under shear load

    International Nuclear Information System (INIS)

    Dimassi, M A; Brauner, C; Herrmann, A S

    2016-01-01

    Sandwich structures with a lightweight closed cell hard foam core have the potential to be used in primary structures of commercial aircrafts. Compared to honeycomb core sandwich, the closed cell foam core sandwich overcomes the issue of moisture take up and makes the manufacturing of low priced and highly integrated structures possible. However, lightweight foam core sandwich materials are prone to failure by localised external loads like low velocity impacts. Invisible cracks could grow in the foam core and threaten the integrity of the structure. In order to enhance the out-of-plane properties of foam core sandwich structures and to improve the damage tolerance (DT) dry fibre bundles are inserted in the foam core. The pins are infused with resin and co-cured with the dry fabric face sheets in an out-of-autoclave process. This study presents the results obtained from shear tests following DIN 53294-standard, on flat sandwich panels. All panels were manufactured with pin-reinforcement manufactured with the Tied Foam Core Technology (TFC) developed by Airbus. The effects of pin material (CFRP and GFRP) and pin volume fraction on the shear properties of the sandwich structure and the crack propagation were investigated and compared to a not pinned reference. It has been concluded that the pin volume fraction has a remarkable effect on the shear properties and damage tolerance of the observed structure. Increasing the pin volume fraction makes the effect of crack redirection more obvious and conserves the integrity of the structure after crack occurrence. (paper)

  17. Magnetic properties of sandwiches based on Nd-Co and Y-Co amorphous alloys

    International Nuclear Information System (INIS)

    Ndjaka, J.M.B.; Givord, D.

    1996-01-01

    Y-Co/Nd-Co/Y-Co and Nd-Co/Y-Co/Nd-Co amorphous sandwiches have been prepared by d.c. triode sputtering. The chemical composition of the constituent layers is R 0.33 Co 0.67 (R=Y, Nd). In such systems, the Co moments are coupled parallel through the whole sandwich thickness by strong positive 3d-3d exchange interactions. But, the coercive fields of the constituent layers taken separately differ. In the sandwiches as well, the reversal of magnetization in the different layers occurs at different values of the applied magnetic field. This phenomenon has been analysed qualitatively in terms of creation and annihilation of walls at the interfaces between layers for sandwiches where the thicknesses of the constituent layers are about 1000 A. In sandwiches where the thickness of the constituent layers is 100 A, the wall width available is very weak and the value of the applied magnetic field necessary for the creation of such a wall is higher than the coercive field of the entire sandwich system. As a result, the magnetization of the sandwich system reverses as a whole like in homogeneous systems. (orig.)

  18. A materials selection procedure for sandwiched beams via parametric optimization with applications in automotive industry

    International Nuclear Information System (INIS)

    Aly, Mohamed F.; Hamza, Karim T.; Farag, Mahmoud M.

    2014-01-01

    Highlights: • Sandwich panels optimization model. • Sandwich panels design procedure. • Study of sandwich panels for automotive vehicle flooring. • Study of sandwich panels for truck cabin exterior. - Abstract: The future of automotive industry faces many challenges in meeting increasingly strict restrictions on emissions, energy usage and recyclability of components alongside the need to maintain cost competiveness. Weight reduction through innovative design of components and proper material selection can have profound impact towards attaining such goals since most of the lifecycle energy usage occurs during the operation phase of a vehicle. In electric and hybrid vehicles, weight reduction has another important effect of extending the electric mode driving range between stops or gasoline mode. This paper adopts parametric models for design optimization and material selection of sandwich panels with the objective of weight and cost minimization subject to structural integrity constraints such as strength, stiffness and buckling resistance. The proposed design procedure employs a pre-compiled library of candidate sandwich panel material combinations, for which optimization of the layered thicknesses is conducted and the best one is reported. Example demonstration studies from the automotive industry are presented for the replacement of Aluminum and Steel panels with polypropylene-filled sandwich panel alternatives

  19. Elisa Live -palvelu : Laajentuminen Ison-Britannian markkinoilla

    OpenAIRE

    Heimolinna, Rami

    2016-01-01

    Tämän opinnäytetyön tarkoituksena oli tuottaa Elisan liiketoimintatiimille tietoa, joka liittyy Elisa Live -palvelun vuonna 2015 alkaneeseen kansainväliseen laajentumiseen. Työn tavoitteita olivat asiakasymmärryksen lisääminen ja tiedon kerääminen Elisan kilpailijoista valitussa myyntikanavassa Amazon-verkkokaupassa. Teoriaosuudessa selvitettiin kilpailutekijöitä, markkinointiviestintää ja kansainvälistymistä. Nykytilanneanalyysissä tutkittiin Isoa-Britanniaa markkina-alueena ja Amazon-ve...

  20. Rubella virus detection by ELISA method in exposed radiation workers

    International Nuclear Information System (INIS)

    Wu Jianmei; Zhu Bo; Zhu Youming; Shao Jinhui; Wu Weiping; Han Jinxiang

    2005-01-01

    Objective: A rapid diagnosis method was developed to detect Rubella virus infection in radiation workers. Methods: Modified ELISA method was used to detect the level of lgG and lgM antibodies in 514 in Jinan district. Results: 90.47% of 514 cases was shown to be resistant against Rubella virus; 6.42% were sensitive type; 0.78% belonged to be reinfected. Conclusion: Detection of Rubella virus in exposed radiation workers was imperative, and vaccine against Rubella virus was also needed to eliminate the infection risk. (authors)

  1. Evaluation Of Antibody Elisa, Coproscopy And Serum Enzyme ...

    African Journals Online (AJOL)

    Le titrage avec immunoadsorbant lié à une enzyme (ELISA), la sédimentation fécale et les tests de l'action de l'enzyme du sérum ont été faits sur des échantillons de fèces et de sérum recueillis de 134 bovins (55 positifs et 79 négatifs pour les lésions dues à la douve du foie) lors de l'inspection de viande en Ethiopie.

  2. Development and application of triple antibody sandwich enzyme-linked immunosorbent assays for begomovirus detection using monoclonal antibodies against Tomato yellow leaf curl Thailand virus.

    Science.gov (United States)

    Seepiban, Channarong; Charoenvilaisiri, Saengsoon; Warin, Nuchnard; Bhunchoth, Anjana; Phironrit, Namthip; Phuangrat, Bencharong; Chatchawankanphanich, Orawan; Attathom, Supat; Gajanandana, Oraprapai

    2017-05-30

    Tomato yellow leaf curl Thailand virus, TYLCTHV, is a begomovirus that causes severe losses of tomato crops in Thailand as well as several countries in Southeast and East Asia. The development of monoclonal antibodies (MAbs) and serological methods for detecting TYLCTHV is essential for epidemiological studies and screening for virus-resistant cultivars. The recombinant coat protein (CP) of TYLCTHV was expressed in Escherichia coli and used to generate MAbs against TYLCTHV through hybridoma technology. The MAbs were characterized and optimized to develop triple antibody sandwich enzyme-linked immunosorbent assays (TAS-ELISAs) for begomovirus detection. The efficiency of TAS-ELISAs for begomovirus detection was evaluated with tomato, pepper, eggplant, okra and cucurbit plants collected from several provinces in Thailand. Molecular identification of begomoviruses in these samples was also performed through PCR and DNA sequence analysis of the CP gene. Two MAbs (M1 and D2) were generated and used to develop TAS-ELISAs for begomovirus detection. The results of begomovirus detection in 147 field samples indicated that MAb M1 reacted with 2 begomovirus species, TYLCTHV and Tobacco leaf curl Yunnan virus (TbLCYnV), whereas MAb D2 reacted with 4 begomovirus species, TYLCTHV, TbLCYnV, Tomato leaf curl New Delhi virus (ToLCNDV) and Squash leaf curl China virus (SLCCNV). Phylogenetic analyses of CP amino acid sequences from these begomoviruses revealed that the CP sequences of begomoviruses recognized by the narrow-spectrum MAb M1 were highly conserved, sharing 93% identity with each other but only 72-81% identity with MAb M1-negative begomoviruses. The CP sequences of begomoviruses recognized by the broad-spectrum MAb D2 demonstrated a wider range of amino acid sequence identity, sharing 78-96% identity with each other and 72-91% identity with those that were not detected by MAb D2. TAS-ELISAs using the narrow-specificity MAb M1 proved highly efficient for the detection of

  3. Design Considerations for Thermally Insulating Structural Sandwich Panels for Hypersonic Vehicles

    Science.gov (United States)

    Blosser, Max L.

    2016-01-01

    Simplified thermal/structural sizing equations were derived for the in-plane loading of a thermally insulating structural sandwich panel. Equations were developed for the strain in the inner and outer face sheets of a sandwich subjected to uniaxial mechanical loads and differences in face sheet temperatures. Simple equations describing situations with no viable solution were developed. Key design parameters, material properties, and design principles are identified. A numerical example illustrates using the equations for a preliminary feasibility assessment of various material combinations and an initial sizing for minimum mass of a sandwich panel.

  4. Veterans' informal caregivers in the "sandwich generation": a systematic review toward a resilience model.

    Science.gov (United States)

    Smith-Osborne, Alexa; Felderhoff, Brandi

    2014-01-01

    Social work theory advanced the formulation of the construct of the sandwich generation to apply to the emerging generational cohort of caregivers, most often middle-aged women, who were caring for maturing children and aging parents simultaneously. This systematic review extends that focus by synthesizing the literature on sandwich generation caregivers for the general aging population with dementia and for veterans with dementia and polytrauma. It develops potential protective mechanisms based on empirical literature to support an intervention resilience model for social work practitioners. This theoretical model addresses adaptive coping of sandwich- generation families facing ongoing challenges related to caregiving demands.

  5. ELISA, a demonstrator environment for information systems architecture design

    Science.gov (United States)

    Panem, Chantal

    1994-01-01

    This paper describes an approach of reusability of software engineering technology in the area of ground space system design. System engineers have lots of needs similar to software developers: sharing of a common data base, capitalization of knowledge, definition of a common design process, communication between different technical domains. Moreover system designers need to simulate dynamically their system as early as possible. Software development environments, methods and tools now become operational and widely used. Their architecture is based on a unique object base, a set of common management services and they host a family of tools for each life cycle activity. In late '92, CNES decided to develop a demonstrative software environment supporting some system activities. The design of ground space data processing systems was chosen as the application domain. ELISA (Integrated Software Environment for Architectures Specification) was specified as a 'demonstrator', i.e. a sufficient basis for demonstrations, evaluation and future operational enhancements. A process with three phases was implemented: system requirements definition, design of system architectures models, and selection of physical architectures. Each phase is composed of several activities that can be performed in parallel, with the provision of Commercial Off the Shelves Tools. ELISA has been delivered to CNES in January 94, currently used for demonstrations and evaluations on real projects (e.g. SPOT4 Satellite Control Center). It is on the way of new evolutions.

  6. Elisa-Like Format for Comparing DNA Capture Elements (Aptamers) to Antibody in Diagnostic Efficacy

    National Research Council Canada - National Science Library

    Kiel, Johnathan L; Holwitt, Eric A; Vivekananda, Jeevalatha; Franz, Veronica

    2004-01-01

    .... For this purpose, the microtiter, heterologous phase, ELISAlike sandwich assay test was chosen. The antigen of choice was the standard antigen used in commercially available agglutination tests for Francisella tularensis (tularemia bacterium...

  7. SIMPLIFIED DIAGNOSIS OF MALARIA INFECTION: GFM/PCR/ELISA A SIMPLIFIED NUCLEIC ACID AMPLIFICATION TECHNIQUE BY PCR/ELISA

    Directory of Open Access Journals (Sweden)

    Ricardo Luiz Dantas MACHADO

    1998-09-01

    Full Text Available We report an adaptation of a technique for the blood sample collection (GFM as well as for the extraction and amplification of Plasmodium DNA for the diagnosis of malaria infection by the PCR/ELISA. The method of blood sample collection requires less expertise and saves both time and money, thus reducing the cost by more than half. The material is also suitable for genetic analysis in either fresh or stored specimens prepared by this method.Relatamos a adaptação de uma técnica para coleta de amostras (MFV e outra para extração, amplificação de DNA de parasitas da malária para diagnóstico por PCR/ELISA. O método de coleta de amostras requer menos habilidade e economisa tempo e dinheiro, assim reduzindo a mais da metade o custo. O material é também adequado para análise genética em especimens frescos ou estocados, preparados por este método.

  8. Numerical comparison of patch and sandwich piezoelectric transducers for transmitting ultrasonic waves

    CSIR Research Space (South Africa)

    Loveday, PW

    2006-03-01

    Full Text Available in the waveguide. Piezoelectric patch transducers are frequently employed, by researchers, for exciting waves in beam like structures. Sonar systems frequently make use of resonant transducers, such as sandwich transducers, for acoustic wave generation...

  9. Measurement of the epithermal neutron flux of the Argonauta reactor by the Sandwich method

    International Nuclear Information System (INIS)

    Nascimento, H.M.

    1973-01-01

    A common method of obtaining information about the neutron spectrum in the energy range of 1 eV to a few keV is by using resonance sandwich detectors. A sandwich detector is usually made up of three foils placed one on top of the other, each having the same thickness and being made of the same material which has a pronounced absorption resonance. To make an adequate evaluation, the sandwich method was compared with one using an isolated detector. The results obtained from approximate theoretical calculations were checked experimentally, using In, Au and Mn foils, in an isotropic 1/E flux in the Argonaut Reactor at I.E.N. As practical application of this method, the deviation from a 1/E spectrum of the epithermal neutron flux in the core and external graphite reflector of the Argonaut Reactor has been measured with the sandwich foils previously calibrated in a 1/E spectrum. (author)

  10. Multi-objective optimal design of sandwich panels using a genetic algorithm

    Science.gov (United States)

    Xu, Xiaomei; Jiang, Yiping; Pueh Lee, Heow

    2017-10-01

    In this study, an optimization problem concerning sandwich panels is investigated by simultaneously considering the two objectives of minimizing the panel mass and maximizing the sound insulation performance. First of all, the acoustic model of sandwich panels is discussed, which provides a foundation to model the acoustic objective function. Then the optimization problem is formulated as a bi-objective programming model, and a solution algorithm based on the non-dominated sorting genetic algorithm II (NSGA-II) is provided to solve the proposed model. Finally, taking an example of a sandwich panel that is expected to be used as an automotive roof panel, numerical experiments are carried out to verify the effectiveness of the proposed model and solution algorithm. Numerical results demonstrate in detail how the core material, geometric constraints and mechanical constraints impact the optimal designs of sandwich panels.

  11. Effects of Core Softness and Bimodularity of Fibreglass Layers on Flexural Stiffness of Polymer Sandwich Structures

    Directory of Open Access Journals (Sweden)

    Šuba Oldřich

    2017-01-01

    Full Text Available This paper deals with the study of the flexural stiffness of the sandwich structures based on fibreglass and polymeric foams. The influence of geometrical and material parameters on the resulting effective flexural stiffness of the sandwich structure is being studied experimentally, analytically and by using FEM models. The effective modulus of elasticity of the sandwich-structured element is being studied and its theoretical and model dependencies on the flexibility of the foam core and bimodularity of the fibreglass layers are being investigated. The achieved results are compared with the experimentally observed values. This study shows that it is necessary to pay special attention to the issue of flexural stiffness of the walls when designing sandwich shell products in order to prevent possible failures in the practical applications of these types of structures.

  12. Effect of varying geometrical parameters of trapezoidal corrugated-core sandwich structure

    Directory of Open Access Journals (Sweden)

    Zaid N.Z.M.

    2017-01-01

    Full Text Available Sandwich structure is an attractive alternative that increasingly used in the transportation and aerospace industry. Corrugated-core with trapezoidal shape allows enhancing the damage resistance to the sandwich structure, but on the other hand, it changes the structural response of the sandwich structure. The aim of this paper is to study the effect of varying geometrical parameters of trapezoidal corrugated-core sandwich structure under compression loading. The corrugated-core specimen was fabricated using press technique, following the shape of trapezoidal shape. Two different materials were used in the study, glass fibre reinforced plastic (GFRP and carbon fibre reinforced plastic (CFRP. The result shows that the mechanical properties of the core in compression loading are sensitive to the variation of a number of unit cells and the core thickness.

  13. Experimental and Theoretical Deflections of Hybrid Composite Sandwich Panel under Four-point Bending Load

    Directory of Open Access Journals (Sweden)

    Jauhar Fajrin

    2017-03-01

    Full Text Available This paper presents a comparison of theoretical and experimental deflection of a hybrid sandwich panel under four-point bending load. The paper initially presents few basic equations developed under three-point load, followed by development of model under four-point bending load and a comparative analysis between theoretical and experimental results. It was found that the proposed model for predicting the deflection of hybrid sandwich panels provided fair agreement with the experimental values. Most of the sandwich panels showed theoretical deflection values higher than the experimental values, which is desirable in the design. It was also noticed that the introduction of intermediate layer does not contribute much to reduce the deflection of sandwich panel as the main contributor for the total deflection was the shear deformation of the core that mostly determined by the geometric of the samples and the thickness of the core.

  14. Two dimensional dynamic analysis of sandwich plates with gradient foam cores

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Lin; Xiao, Deng Bao; Zhao, Guiping [State Key Laboratory for Mechanical structure Strength and Vibration, School of AerospaceXi' an Jiaotong University, Xi' an (China); Cho, Chong Du [Dept. of Mechanical Engineering, Inha University, Inchon (Korea, Republic of)

    2016-09-15

    Present investigation is concerned about dynamic response of composite sandwich plates with the functionally gradient foam cores under time-dependent impulse. The analysis is based on a model of the gradient sandwich plate, in which the face sheets and the core adopt the Kirchhoff theory and a [2, 1]-order theory, respectively. The material properties of the gradient foam core vary continuously along the thickness direction. The gradient plate model is validated with the finite element code ABAQUS®. And the results show that the proposed model can predict well the free vibration of composite sandwich plates with gradient foam cores. The influences of gradient foam cores on the natural frequency, deflection and energy absorbing of the sandwich plates are also investigated.

  15. Novel sandwich structure adsorptive membranes for removal of 4-nitrotoluene from water

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yuexin [College of Chemistry, Beijing Normal University, Beijing 100875 (China); School of Pharmacy, North China University of Science and Technology, Tangshan 063000 (China); Jia, Zhiqian, E-mail: zhqjia@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China)

    2016-11-05

    Highlights: • Novel sandwich PES-SPES/PS-PDVB/PTFE adsorptive membranes were prepared. • The removal efficiency for 4-nitrotoluene is greater than 95% after five recycles. • The membrane showed higher adsorption capacity than that of mixed matrix membrane. - Abstract: Novel sandwich PES-SPES/PS-PDVB/PTFE adsorptive membranes were prepared by a filtration/immersion precipitation method and employed for the removal of 4-nitrotoluene from water. The static adsorption thermodynamics, kinetics, dynamic adsorption/desorption and membrane reusability were investigated. The results showed that the Freundlich model describes the adsorption isotherm satisfactorily. With increased PS-PDVB content, the maximum static adsorption capacity, partition coefficient, apparent adsorption rate constant, and dynamic adsorption capacity all significantly increased. The sandwich membranes showed much higher removal efficiency and adsorption capacity than those of mixed matrix membranes. With respect to dynamics adsorption/desorption, the sandwich membranes exhibited excellent reusability, with a removal efficiency greater than 95% even after five recycles.

  16. Size-dependent analysis of a sandwich curved nanobeam integrated with piezomagnetic face-sheets

    Directory of Open Access Journals (Sweden)

    Ashraf M. Zenkour

    Full Text Available The aim of this research is to develop nonlocal transient magneto-electro-elastic formulation of a sandwich curved nanobeam including a nano-core and two piezo-magnetic face-sheets subjected to transverse mechanical loads and applied electric and magnetic potentials rest on Pasternak’s foundation. Nonlocal magneto-electro-elastic relations and Hamilton’s principle are used for derivation of the governing equations of motion. The analytical solution based on Fourier solution is presented for a simply-supported sandwich curved nanobeam. The numerical results are presented to investigate influence of significant parameters such as nonlocal parameter, radius of curvature, applied electric and magnetic potentials and two parameters of Pasternak's foundation on the dynamic responses of sandwich curved nanobeam. Keywords: Sandwich curved nanobeam, Dynamic responses, Piezo-magnetic face-sheets, Pasternak’s foundation, Radius of curvature, Nonlocal parameter

  17. Study of low-velocity impact response of sandwich panels with shear-thickening gel cores

    Science.gov (United States)

    Wang, Yunpeng; Gong, Xinglong; Xuan, Shouhu

    2018-06-01

    The low-velocity impact response of sandwich panels with shear-thickening gel cores was studied. The impact tests indicated that the sandwich panels with shear-thickening gel cores showed excellent properties of energy dissipation and stress distribution. In comparison to the similar sandwich panels with chloroprene rubber cores and ethylene-propylene-diene monomer cores, the shear-thickening gel cores led to the obviously smaller contact forces and the larger energy absorptions. Numerical modelling with finite element analysis was used to investigate the stress distribution of the sandwich panels with shear-thickening gel cores and the results agreed well with the experimental results. Because of the unique mechanical property of the shear-thickening gel, the concentrated stress on the front facesheets were distributed to larger areas on the back facesheets and the peak stresses were reduced greatly.

  18. High performance sandwich structured Si thin film anodes with LiPON coating

    Science.gov (United States)

    Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

    2018-04-01

    The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solidelectrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

  19. The dynamic properties of sandwich structures based on metal-ceramic foams.

    Science.gov (United States)

    2014-01-01

    The present research program has studied the fracture properties of closed pore metal-ceramic foams for their potential applications as core systems in sandwich structures. The composite foams were created at Fireline, Inc. (Youngstown, OH) using the...

  20. Occurrence of Foodborne Pathogens in Chickens Sandwiches Distributed in Different Supermarkets of Tehran Province, Iran

    OpenAIRE

    Zohreh Mashak; Hamidreza Sodagari; Behrooz Moraadi; Ashkan Ilkhanipour

    2014-01-01

    Background: Increasing urbanization, immigration and tourism has changed the human lifestyle. This modern lifestyle has demanded safety, quality, and fast availability of ready to eat (RTE) foods like chicken sandwiches. Objectives: For presentation of proper solutions regarding food safety, identification of pathogens in different foods is necessary. Therefore, the present study was carried out to assess the microbiological quality of chicken sandwiches distributed in Tehran provinc...

  1. Sensory Evaluation and Feasibility Report of Plantain Sandwich for Nigerian Market

    OpenAIRE

    Olu Malomo; E.O. Uche; E.A. Alamu

    2015-01-01

    Protein-energy malnutrition is a common nutritional disorder in developing countries and constitutes a major public health problem in young children and elderly people. This project is aimed at evaluating the acceptability of plantain-peanut sandwich and roasted at different temperatures. A plantain-peanut sandwich consists of minced protein stuffed into a carbohydrate source made into a roll as a food product. The plantain was roasted at two different temperatures than later enriched with 5%...

  2. Photocatalytic perfermance of sandwich-like BiVO{sub 4} sheets by microwave assisted synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Suqin, E-mail: liusuqin888@126.com [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Xiangyang 441053 (China); Tang, Huiling; Zhou, Huan [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Dai, Gaopeng, E-mail: dgp2000@126.com [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Wang, Wanqiang [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China)

    2017-01-01

    Graphical abstract: Sandwich-like BiVO{sub 4} sheets were successfully synthesized via a facile microwave-assisted method. The as-prepared samples exhibit a high activity for the degradation of methyl orange under visible light irradiation. - Highlights: • Sandwich-like BiVO{sub 4} sheets were synthesized by a facile microwave-assisted method. • The presence of PEG-10000 plays a critical role in the formation of BiVO{sub 4} sheets. • Ostwald ripening is the primary driving force for the formation of sandwich-like BiVO{sub 4}. • The sandwich-like BiVO{sub 4} sheets exhibit a high visible-light photocatalytic activity. - Abstract: Sandwich-like BiVO{sub 4} 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, N{sub 2} 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 BiVO{sub 4} sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO{sub 4} 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 BiVO{sub 4} sheets can be attributed to its large surface area over the irregular BiVO{sub 4} particles.

  3. Assessment of foam fracture in sandwich beams using thermoelastic stress analysis

    DEFF Research Database (Denmark)

    Dulieu-Barton, J.M.; Berggreen, Christian; Mettemberg, C.

    2009-01-01

    Thermoelastic Stress Analysis (TSA) has been well established for determining crack-tip parameters in metallic materials. This paper examines its ability to determine accurately the crack-tip parameters for PVC foam used in sandwich structures.......Thermoelastic Stress Analysis (TSA) has been well established for determining crack-tip parameters in metallic materials. This paper examines its ability to determine accurately the crack-tip parameters for PVC foam used in sandwich structures....

  4. Numerical analysis of sandwich beam with corrugated core under three-point bending

    Energy Technology Data Exchange (ETDEWEB)

    Wittenbeck, Leszek [Poznan University of Technology, Institute of Mathematics Piotrowo Street No. 5, 60-965 Poznan (Poland); Grygorowicz, Magdalena; Paczos, Piotr [Poznan University of Technology, Institute of Applied Mechanics Jana Pawla IIStreet No. 24, 60-965 Poznan (Poland)

    2015-03-10

    The strength problem of sandwich beam with corrugated core under three-point bending is presented.The beam are made of steel and formed by three mutually orthogonal corrugated layers. The finite element analysis (FEA) of the sandwich beam is performed with the use of the FEM system - ABAQUS. The relationship between the applied load and deflection in three-point bending is considered.

  5. Photocatalytic perfermance of sandwich-like BiVO_4 sheets by microwave assisted synthesis

    International Nuclear Information System (INIS)

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

    2017-01-01

    Graphical abstract: Sandwich-like BiVO_4 sheets were successfully synthesized via a facile microwave-assisted method. The as-prepared samples exhibit a high activity for the degradation of methyl orange under visible light irradiation. - Highlights: • Sandwich-like BiVO_4 sheets were synthesized by a facile microwave-assisted method. • The presence of PEG-10000 plays a critical role in the formation of BiVO_4 sheets. • Ostwald ripening is the primary driving force for the formation of sandwich-like BiVO_4. • The sandwich-like BiVO_4 sheets exhibit a high visible-light photocatalytic activity. - Abstract: Sandwich-like BiVO_4 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, N_2 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 BiVO_4 sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO_4 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 BiVO_4 sheets can be attributed to its large surface area over the irregular BiVO_4 particles.

  6. Electrical switching and memory phenomena observed in redox-gradient dendrimer sandwich devices

    OpenAIRE

    Li, JianChang; Blackstock, Silas C.; Szulczewski, Greg J.

    2005-01-01

    We report on the fabrication of dendrimer sandwich devices with electrical switching and memory properties. The storage media is consisted of a redox-gradient dendrimer layer sandwiched in organic barrier thin films. The dendrimer layer acts as potential well where redox-state changes and consequent electrical transitions of the embedded dendrimer molecules are expected to be effectively triggered and retained, respectively. Experimental results indicated that electrical switching could be re...

  7. Sandwich panels with high performance concrete thin plates at elevated temperatures

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2015-01-01

    concerned HMT modelling and elastic stress analysis with nonlinear temperature effects of a full size loaded sandwich wall, qualitatively assessing the location of critically stressed zones. Modelling output was compared to published experimental results. The model reproduced experimental temperature...... recordings satisfactorily, except phase changes of water at low heating rates. It was suggested that the function governing moisture evolution with temperature and pressure should be updated for HPC. Pore pressure was found critical for sandwich structures due their higher temperatures. Adding polypropylene...

  8. Polyisocyanurate systems for insulating and sandwich elements; Polyisocyanurat-Systeme fuer Daemm- und Sandwichelemente

    Energy Technology Data Exchange (ETDEWEB)

    Malotki, P. von [Elastogran GmbH, Lemfoerde (Germany)

    2000-07-01

    PUR rigid foam plates are laminated with flexible Al films, paper or glass non-wovens, or may be processed into sandwich elements with metallic top-layers via coil-coating. Dependence of heat insulation efficiency, dimensional stability and fire behavior of the foam on chemical composition and the blowing agents is considered and compared with polyisocyanurate foams. Recipes for the production of PIR heat insulation elements and sandwich elements are given.

  9. Numerical investigation of blanking for metal polymer sandwich sheets

    Directory of Open Access Journals (Sweden)

    Gutknecht Florian

    2016-01-01

    Full Text Available Metal polymer sandwich sheets consist of materials with drastically different mechanical properties. Due to this fact and because of high local gradients in the cutting zone during the blanking process, traditional process strategies and empirical knowledge are difficult to apply. A finite-element simulation of the shear cutting process is used to predict the necessary force and the geometry of the cutting surface. A fully-coupled ductile damage model is used for the description of the material behaviour. This model considers the influence of shear and compression-dominated stress states on the initiation of damage. Experimental tensile and compression test data is used for the identification of material parameters. The results of the blanking simulation are compared with experimental data. Furthermore, the evolution of the stress state is analysed to gain understanding of the underlying physics. Finally this model enables the prediction of core compression and other quantities such as the acting stresses and corresponding triaxilities, which provide valuable information for the development of analytical models.

  10. Bi-layer sandwich film for antibacterial catheters.

    Science.gov (United States)

    Franz, Gerhard; Schamberger, Florian; Zare, Hamideh Heidari; Bröskamp, Sara Felicitas; Jocham, Dieter

    2017-01-01

    Background: Approximately one quarter of all nosocomial infections can be attributed to the urinary tract. The infections are supposed to be mainly caused by implantations of urethral catheters and stents. A new catheter design is introduced with the aim to lower the high number of nosocomial urethral infections. In order to avoid limitations to use, the design is first applied to conventional commercially available balloon catheters. Results: The main feature of the design is a sandwich layer on both sides of the catheter wall, which is composed of a fragmented base layer of silver capped by a thin film of poly( p -xylylene). This top layer is mainly designed to release a controlled amount of Ag + ions, which is bactericidal, but not toxic to humans. Simultaneously, the lifetime is prolonged to at least one year. The base layer is electrolessly deposited applying Tollens' reagens, the cap layer is deposited by using chemical vapor deposition. Conclusion: The three main problems of this process, electroless deposition of a fragmented silver film on the surface of an electrically insulating organic polymer, irreproducible evaporation during heating of the precursor, and exponential decrease of the layer thickness along the capillary, have been solved trough the application of a simple electrochemical reaction and two standard principles of physics: Papin's pot and the principle of Le Chatelier.

  11. Bi-layer sandwich film for antibacterial catheters

    Directory of Open Access Journals (Sweden)

    Gerhard Franz

    2017-09-01

    Full Text Available Background: Approximately one quarter of all nosocomial infections can be attributed to the urinary tract. The infections are supposed to be mainly caused by implantations of urethral catheters and stents. A new catheter design is introduced with the aim to lower the high number of nosocomial urethral infections. In order to avoid limitations to use, the design is first applied to conventional commercially available balloon catheters.Results: The main feature of the design is a sandwich layer on both sides of the catheter wall, which is composed of a fragmented base layer of silver capped by a thin film of poly(p-xylylene. This top layer is mainly designed to release a controlled amount of Ag+ ions, which is bactericidal, but not toxic to humans. Simultaneously, the lifetime is prolonged to at least one year. The base layer is electrolessly deposited applying Tollens’ reagens, the cap layer is deposited by using chemical vapor deposition.Conclusion: The three main problems of this process, electroless deposition of a fragmented silver film on the surface of an electrically insulating organic polymer, irreproducible evaporation during heating of the precursor, and exponential decrease of the layer thickness along the capillary, have been solved trough the application of a simple electrochemical reaction and two standard principles of physics: Papin’s pot and the principle of Le Chatelier.

  12. Simulations of backgate sandwich nanowire MOSFETs with improved device performance

    International Nuclear Information System (INIS)

    Zhao Hengliang; Zhu Huilong; Zhong Jian; Ma Xiaolong; Wei Xing; Zhao Chao; Chen Dapeng; Ye Tianchun

    2014-01-01

    We propose a novel backgate sandwich nanowire MOSFET (SNFET), which offers the advantages of ETSOI (dynamic backgate voltage controllability) and nanowire FETs (good short channel effect). A backgate is used for threshold voltage (V t ) control of the SNFET. Compared with a backgate FinFET with a punch-through stop layer (PTSL), the SNFET possesses improved device performance. 3D device simulations indicate that the SNFET has a three times larger overdrive current, a ∼75% smaller off leakage current, and reduced subthreshold swing (SS) and DIBL than those of a backgate FinFET when the nanowire (NW) and the fin are of equal width. A new process flow to fabricate the backgate SNFET is also proposed in this work. Our analytical model suggests that V t control by the backgate can be attributed to the capacitances formed by the frontgate, NW, and backgate. The SNFET devices are compatible with the latest state-of-the-art high-k/metal gate CMOS technology with the unique capability of independent backgate control for nFETs and pFETs, which is promising for sub-22 nm scaling down. (semiconductor devices)

  13. Microkeratome-assisted lamellar keratoplasty for keratoconus: stromal sandwich.

    Science.gov (United States)

    Bilgihan, Kamil; Ozdek, Sengül C; Sari, Ayça; Hasanreisoglu, Berati

    2003-07-01

    To evaluate microkeratome-assisted lamellar keratoplasty for the treatment of keratoconus when it is not possible to correct the astigmatic ametropia with contact lenses. Ophthalmology Department, School of Medicine, Gazi University, Ankara, Turkey. This prospective study comprised 9 eyes of 7 keratoconus patients with contact lens intolerance. The donor cornea was prepared with a microkeratome and punched with a 7.25 mm or 7.50 mm trephine. Following the creation of a standard 9.0 mm corneal flap in the host cornea, the donor stromal button was implanted under this corneal flap like a sandwich. Transepithelial photorefractive keratectomy or laser in situ keratomileusis was performed when the corneal topography and refraction stabilized by the end of the sixth postoperative month. Follow-up ranged from 7 to 22 months. All patients gained 5 or more lines (mean 7.2 lines +/- 1.6 [SD]), and no patient lost a line of vision. The mean corneal thickness was 432.7 +/- 36.1 micrometers preoperatively and 578.1 +/- 45.1 micrometers after refractive surgery. The early visual results of this surgical technique are promising and seem to be comparable to those with penetrating keratoplasty.

  14. Dispersion of Lamb waves in a honeycomb composite sandwich panel.

    Science.gov (United States)

    Baid, Harsh; Schaal, Christoph; Samajder, Himadri; Mal, Ajit

    2015-02-01

    Composite materials are increasingly being used in advanced aircraft and aerospace structures. Despite their many advantages, composites are often susceptible to hidden damages that may occur during manufacturing and/or service of the structure. Therefore, safe operation of composite structures requires careful monitoring of the initiation and growth of such defects. Ultrasonic methods using guided waves offer a reliable and cost effective method for defects monitoring in advanced structures due to their long propagation range and their sensitivity to defects in their propagation path. In this paper, some of the useful properties of guided Lamb type waves are investigated, using analytical, numerical and experimental methods, in an effort to provide the knowledge base required for the development of viable structural health monitoring systems for composite structures. The laboratory experiments involve a pitch-catch method in which a pair of movable transducers is placed on the outside surface of the structure for generating and recording the wave signals. The specific cases considered include an aluminum plate, a woven composite laminate and an aluminum honeycomb sandwich panel. The agreement between experimental, numerical and theoretical results are shown to be excellent in certain frequency ranges, providing a guidance for the design of effective inspection systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The Response of Clamped Shallow Sandwich Arches with Metallic Foam Cores to Projectile Impact Loading

    Directory of Open Access Journals (Sweden)

    Yanping Fan

    Full Text Available Abstract The dynamic response and energy absorption capabilities of clamped shallow sandwich arches with aluminum foam core were numerically investigated by impacting the arches at mid-span with metallic foam projectiles. The typical deformation modes, deflection response, and core compression of sandwich arches obtained from the tests were used to validate the computation model. The resistance to impact loading was quantified by the permanent transverse deflection at mid-span of the arches as a function of projectile momentum. The sandwich arches have a higher shock resistance than the monolithic arches of equal mass, and shock resistance could be significantly enhanced by optimizing geometrical configurations. Meanwhile, decreasing the face-sheet thickness and curvature radius could enhance the energy absorption capability of the sandwich arches. Finite element calculations indicated that the ratio of loading time to structural response time ranged from 0.1 to 0.4. The projectile momentum, which was solely used to quantify the structural response of sandwich arches, was insufficient. These findings could provide guidance in conducting further theoretical studies and producing the optimal design of metallic sandwich structures subjected to impact loading.

  16. Finite element simulation of low velocity impact loading on a sandwich composite

    Directory of Open Access Journals (Sweden)

    Vishwas M.

    2018-01-01

    Full Text Available Sandwich structure offer more advantage in bringing flexural stiffness and energy absorption capabilities in the application of automobile and aerospace components. This paper presents comparison study and analysis of two types of composite sandwich structures, one having Jute Epoxy skins with rubber core and the other having Glass Epoxy skins with rubber core subjected to low velocity normal impact loading. The behaviour of sandwich structure with various parameters such as energy absorption, peak load developed, deformation and von Mises stress and strain, are analyzed using commercially available analysis software. The results confirm that sandwich composite with jute epoxy skin absorbs approximately 20% more energy than glass epoxy skin. The contact force developed in jute epoxy skin is approximately 2.3 times less when compared to glass epoxy skin. von Mises stress developed is less in case of jute epoxy. The sandwich with jute epoxy skin deforms approximately 1.6 times more than that of same geometry of sandwich with glass epoxy skin. Thus exhibiting its elastic nature and making it potential candidate for low velocity impact application.

  17. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    Science.gov (United States)

    Nordendale, Nikolas A.; Goyal, Vinay K.; Lundgren, Eric C.; Patel, Dhruv N.; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth N.

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  18. 3D Energy Absorption Diagram Construction of Paper Honeycomb Sandwich Panel

    Directory of Open Access Journals (Sweden)

    Dongmei Wang

    2018-01-01

    Full Text Available Paper honeycomb sandwich panel is an environment-sensitive material. Its cushioning property is closely related to its structural factors, the temperature and humidity, random shocks, and vibration events in the logistics environment. In order to visually characterize the cushioning property of paper honeycomb sandwich panel in different logistics conditions, the energy absorption equation of per unit volume of paper honeycomb sandwich panel was constructed by piecewise function. The three-dimensional (3D energy absorption diagram of paper honeycomb sandwich panel was constructed by connecting the inflexion of energy absorption curve. It takes into account the temperature, humidity, strain rate, and characteristics of the honeycomb structure. On the one hand, this diagram breaks through the limitation of the static compression curve of paper honeycomb sandwich panel, which depends on the test specimen and is applicable only to the standard condition. On the other hand, it breaks through the limitation of the conventional 2D energy absorption diagram which has less information. Elastic modulus was used to normalize the plateau stress and energy absorption per unit volume. This makes the 3D energy absorption diagram universal for different material sandwich panels. It provides a new theoretical basis for packaging optimized design.

  19. Analysis of syntactic foam – GFRP sandwich composites for flexural loads

    Science.gov (United States)

    Paul, Daniel; Velmurugan, R.; Jayaganthan, R.; Gupta, N. K.; Manzhirov, A. V.

    2018-04-01

    The use of glass microballoon (GMB) — epoxy syntactic foams as a sandwich core material is studied. The skins and foam core are fabricated and joined instantaneously unlike the procedures followed in the previous studies. Each successive layer of the sandwich is fabricated when the previous layer is in a semi-gelled state. These sandwich samples are characterized for their properties under flexural loading. The failure modes and mechanical properties are carefully investigated. The change in fabrication technique results in a significant increase in the load bearing pattern of the sandwich. In earlier studies, debonding was found to occur prematurely since the bonding between the skins and core is the weakest plane. Using the current technique, core cracking occurs first, followed by skin fiber breaking and debonding happens at the end. This ensures that the load carrying phase of the structure is extended considerably. The sandwich is also analytically studied using Reddy’s higher order shear deformation theory. A higher order theory is selected as the sandwich can no longer be considered as a thin beam and thus shear effects also need to be considered in addition to bending effects.

  20. Parametric study on nonlinear vibration of composite truss core sandwich plate with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jia Nen; Liu, Jun [Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, Tianjin University of Technology, Tianjin (China); Zhang, Wei; Yao, Ming Hui [College of Mechanical Engineering, Beijing University of Technology, Beijing (China); Sun, Min [School of Science, Tianjin Chengjian University, Tianjin (China)

    2016-09-15

    Nonlinear vibrations of carbon fiber reinforced composite sandwich plate with pyramidal truss core are investigated. The governing equation of motion for the sandwich plate is derived by using a Zig-Zag theory under consideration of geometrically nonlinear. The natural frequencies of sandwich plates with different dimensions are calculated and compared with those obtained from the classic laminated plate theory and Reddy's third-order shear deformation plate theory. The frequency responses and waveforms of the sandwich plate when 1:3 internal resonance occurs are obtained, and the characteristics of the internal resonance are discussed. The influences of layer number of face sheet, strut radius, core height and inclination angle on the nonlinear responses of the sandwich plate are analyzed. The results demonstrate that the strut radius and inclination angle mainly affect the resonance frequency band of the sandwich plate, and the layer number and core height not only influence the resonance frequency band but also significantly affect the response amplitude.

  1. The Electron Cyclotron Resonance Light Source Assembly of PTB - ELISA

    CERN Document Server

    Gruebling, P; Ulm, G

    1999-01-01

    In the radiometry laboratory of the Physikalisch-Technische,Bundesanstalt at the Berlin electron storage ring BESSY I, radiation sources for radiometric applications in industry and basic research in the vacuum ultraviolet (VUV) spectral range are developed, characterized and calibrated. Established sources such as deuterium lamps, Penning and hollow cathode discharge sources have limited spectral ranges and in particular their stability and life time suffers from the erosion of the cathode material. To overcome these limitations we have developed a radiation source based on the principle of the electron cyclotron resonance ion source. ELISA is a 10 GHz monomode source with a compact design featuring a tunable cavity and axially positionable permanent magnets. The radiation emission of the source can be detected simultaneously in the VUV and X-ray spectral range via a toroidal grating monochromator and a Si(Li)-detector. The special design of the source allows spectroscopic investigations of the plasma in dep...

  2. Elisa Mújica: verdadera vocación por la escritura

    Directory of Open Access Journals (Sweden)

    Nelly Rocío Amaya Méndez

    2001-01-01

    Full Text Available Son excepcionales las escritoras colombianas de las que puede decirse que con su obra han conquistado las más altas cimas del valor literario en géneros como la novela, el cuento y el ensayo, y obtenido al mismo tiempo su consagración dentro del ámbito de las letras hispanoamericanas. Es el caso de doña Elisa Mújica, considerada modelo en el arte de escribir en Colombia gracias a su dedicación y disciplina durante decenios de continuo quehacer literario, siendo la primera mujer en ser admitida en la Academia Colombiana de la Lengua y como miembro correspondiente de la Real Academia Española

  3. ELISA for Detection of Soya Proteins in Meat Products

    Directory of Open Access Journals (Sweden)

    Eva Renčová

    2009-01-01

    Full Text Available Indirect competitive ELISA method for the detection of soya proteins in meat products was developed. The detection limit of the method is 0.5% of the weight of added soya protein. A total of 131 meat product samples such as salamis or sausages from the Czech Republic market were investigated for the presence of soya proteins. Soya proteins were detected in 84% of the investigated samples without any declaration on the package of the product. The use of vegetable additives, namely soya in meat products in the market of the Czech Republic is very frequent and the restriction of its usage by legislation relates only to some kinds of durable products and ham (Act 264/2003 Coll.. The need for sensitive inspecting methods for soya protein detection is not only associated with the economic aspect (adulteration, but mainly with consumer health protection in case of allergy to soya proteins.

  4. Development and evaluation of a competitive ELISA using a monoclonal antibody for antibody detection after goose parvovirus virus-like particles (VLPs) and vaccine immunization in goose sera.

    Science.gov (United States)

    Wang, Qian; Ju, Huanyu; Li, Yanwei; Jing, Zhiqiang; Guo, Lu; Zhao, Yu; Ma, Bo; Gao, Mingchun; Zhang, Wenlong; Wang, Junwei

    2014-12-01

    An assay protocol based on a monoclonal antibody-based competitive enzyme-linked immunosorbent assay (MAb-based C-ELISA) for detecting antibodies against goose parvovirus (GPV) and its virus-like particles (VLPs) is described. The assay was developed using baculovirus-expressed recombinant VP2 virus-like particles (rVP2-VLPs) as antigens and a monoclonal antibody against GPV as the competitive antibody. Of the four anti-GPV MAbs that were screened, MAb 1G3 was selected as it was blocked by the GPV positive serum. Based on the distribution of percent inhibition (PI) of the known negative sera (n=225), a cut-off value was set at 36% inhibition. Using this cut-off value, the sensitivity of the assay was 93.3% and the specificity was 95.8%, as compared with the gold standard (virus neutralization assay). The rVP2-VLPs did not react with anti-sera to other goose pathogens, indicating that it is specific for the recognization of goose parvovirus antibodies. The assay was then validated with serum samples from goslings vaccinated with several VLPs (rVP1-VLPs, rVP2-VLPs, rVP3-VLPs, and rCGV-VLPs) and other vaccines (inactivated and attenuated). The C-ELISA described in this study is a sensitive and specific diagnostic test and should have wide applications for the sero-diagnosis and immunologic surveillance of GPV. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Rational design and validation of an anti-protein kinase C active-state specific antibody based on conformational changes.

    Science.gov (United States)

    Pena, Darlene Aparecida; Andrade, Victor Piana de; Silva, Gabriela Ávila Fernandes; Neves, José Ivanildo; Oliveira, Paulo Sergio Lopes de; Alves, Maria Julia Manso; Devi, Lakshmi A; Schechtman, Deborah

    2016-02-25

    Protein kinase C (PKC) plays a regulatory role in key pathways in cancer. However, since phosphorylation is a step for classical PKC (cPKC) maturation and does not correlate with activation, there is a lack of tools to detect active PKC in tissue samples. Here, a structure-based rational approach was used to select a peptide to generate an antibody that distinguishes active from inactive cPKC. A peptide conserved in all cPKCs, C2Cat, was chosen since modeling studies based on a crystal structure of PKCβ showed that it is localized at the interface between the C2 and catalytic domains of cPKCs in an inactive kinase. Anti-C2Cat recognizes active cPKCs at least two-fold better than inactive kinase in ELISA and immunoprecipitation assays, and detects the temporal dynamics of cPKC activation upon receptor or phorbol stimulation. Furthermore, the antibody is able to detect active PKC in human tissue. Higher levels of active cPKC were observed in the more aggressive triple negative breast cancer tumors as compared to the less aggressive estrogen receptor positive tumors. Thus, this antibody represents a reliable, hitherto unavailable and a valuable tool to study PKC activation in cells and tissues. Similar structure-based rational design strategies can be broadly applied to obtain active-state specific antibodies for other signal transduction molecules.

  6. Identification of Surface Protein Biomarkers of Listeria monocytogenes via Bioinformatics and Antibody-Based Protein Detection Tools

    Science.gov (United States)

    Zhang, Cathy X. Y.; Brooks, Brian W.; Huang, Hongsheng; Pagotto, Franco

    2016-01-01

    ABSTRACT The Gram-positive bacterium Listeria monocytogenes causes a significant percentage of the fatalities among foodborne illnesses in humans. Surface proteins specifically expressed in a wide range of L. monocytogenes serotypes under selective enrichment culture conditions could serve as potential biomarkers for detection and isolation of this pathogen via antibody-based methods. Our study aimed to identify such biomarkers. Interrogation of the L. monocytogenes serotype 4b strain F2365 genome identified 130 putative or known surface proteins. The homologues of four surface proteins, LMOf2365_0578, LMOf2365_0581, LMOf2365_0639, and LMOf2365_2117, were assessed as biomarkers due to the presence of conserved regions among strains of L. monocytogenes which are variable among other Listeria species. Rabbit polyclonal antibodies against the four recombinant proteins revealed the expression of only LMOf2365_0639 on the surface of serotype 4b strain LI0521 cells despite PCR detection of mRNA transcripts for all four proteins in the organism. Three of 35 monoclonal antibodies (MAbs) to LMOf2365_0639, MAbs M3643, M3644, and M3651, specifically recognized 42 (91.3%) of 46 L. monocytogenes lineage I and II isolates grown in nonselective brain heart infusion medium. While M3644 and M3651 reacted with 14 to 15 (82.4 to 88.2%) of 17 L. monocytogenes lineage I and II isolates, M3643 reacted with 22 (91.7%) of 24 lineage I, II, and III isolates grown in selective enrichment media (UVM1, modified Fraser, Palcam, and UVM2 media). The three MAbs exhibited only weak reactivities (the optical densities at 414 nm were close to the cutoff value) to some other Listeria species grown in selective enrichment media. Collectively, the data indicate the potential of LMOf2365_0639 as a surface biomarker of L. monocytogenes, with the aid of specific MAbs, for pathogen detection, identification, and isolation in clinical, environmental, and food samples. IMPORTANCE L. monocytogenes is

  7. A quantitative exposure model simulating human norovirus transmission during preparation of deli sandwiches.

    Science.gov (United States)

    Stals, Ambroos; Jacxsens, Liesbeth; Baert, Leen; Van Coillie, Els; Uyttendaele, Mieke

    2015-03-02

    Human noroviruses (HuNoVs) are a major cause of food borne gastroenteritis worldwide. They are often transmitted via infected and shedding food handlers manipulating foods such as deli sandwiches. The presented study aimed to simulate HuNoV transmission during the preparation of deli sandwiches in a sandwich bar. A quantitative exposure model was developed by combining the GoldSim® and @Risk® software packages. Input data were collected from scientific literature and from a two week observational study performed at two sandwich bars. The model included three food handlers working during a three hour shift on a shared working surface where deli sandwiches are prepared. The model consisted of three components. The first component simulated the preparation of the deli sandwiches and contained the HuNoV reservoirs, locations within the model allowing the accumulation of NoV and the working of intervention measures. The second component covered the contamination sources being (1) the initial HuNoV contaminated lettuce used on the sandwiches and (2) HuNoV originating from a shedding food handler. The third component included four possible intervention measures to reduce HuNoV transmission: hand and surface disinfection during preparation of the sandwiches, hand gloving and hand washing after a restroom visit. A single HuNoV shedding food handler could cause mean levels of 43±18, 81±37 and 18±7 HuNoV particles present on the deli sandwiches, hands and working surfaces, respectively. Introduction of contaminated lettuce as the only source of HuNoV resulted in the presence of 6.4±0.8 and 4.3±0.4 HuNoV on the food and hand reservoirs. The inclusion of hand and surface disinfection and hand gloving as a single intervention measure was not effective in the model as only marginal reductions of HuNoV levels were noticeable in the different reservoirs. High compliance of hand washing after a restroom visit did reduce HuNoV presence substantially on all reservoirs. The

  8. Evaluation of an indirect ELISA for detection and typing of foot-and-mouth disease virus

    International Nuclear Information System (INIS)

    Prado, J.A.

    1998-01-01

    An indirect enzyme linked immunosorbent assay (ELISA) kit was used for diagnosis of foot-and-mouth disease virus (FMDV) types O1, A23, C3 which occurred in Rio Grande do Sul State, Southern Brazil during 1984-1994. The samples were randomly selected and tested by ELISA, Complement Fixation Test (CFT) and in tissue culture. Out of 106 samples 78 (73,5%) were positive by ELISA and 39 (36,8%) were found positive in CFT, when original suspensions were used. Once these samples were inoculated onto tissue culture both tests gave similar results, although ELISA picked up more positive samples during the 1st passage in tissue culture. The negative samples (16) included in this study were negative in all tests. The ELISA was more sensitive than and as specific as CFT. ELISA and tissue culture together were shown to be a better system for detection of foot-and-mouth disease virus antigen than CFT. (author)

  9. Fasciola hepatica saposin-like-2 protein based ELISA for the serodiagnosis of chronic human fascioliasis

    Science.gov (United States)

    Figueroa-Santiago, Olgary; Delgado, Bonnibel; Espino, Ana M.

    2011-01-01

    An indirect enzyme-linked immunosorbent assay (ELISA) was developed and evaluated for its diagnostic ability to detect human IgG antibodies against Fasciola hepatica saposin-like protein-2. The assay was compared with an indirect ELISA with excretory-secretory products (FhES) from adult F. hepatica. In an analysis of the sera of 37 patients infected with F. hepatica, 40 patients with other parasitic infections, and 50 healthy controls, the sensitivity of both ELISA assays was 100%. However, the FhSAP2-based ELISA was more specific (95.6%) than the FhES-ELISA (91.9%). These results demonstrated that FhSAP2 can be used in the serodiagnosis of chronic human fascioliasis with additional advantage that is relative cheap and easy to produce. Studies are in progress to evaluate this FhSAP2-ELISA assay in a large-scale prevalence surveys in endemic areas. PMID:21683266

  10. An ultra-sensitive monoclonal antibody-based enzyme-linked immunosobent assay for dibutyl phthalate in human urinary

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Lifang [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, College of Pharmaceutical Science, Zhejiang University, Hangzhou 310058 (China); Lei, Yajing [Hangzhou EPIE Bio-detection Technology Limited, Hangzhou 310051 (China); Zhang, Dai; Ahmed, Shabbir [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, College of Pharmaceutical Science, Zhejiang University, Hangzhou 310058 (China); Chen, Shuqing, E-mail: chenshuqing@zju.edu.cn [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, College of Pharmaceutical Science, Zhejiang University, Hangzhou 310058 (China)

    2016-01-15

    Dibutyl phthalate (DBP) has been extensively used as a plasticizer in many daily products, which is highly toxic to human, notably affecting the reproductive and developmental function. As the previous method is expensive, time-consuming, low sensitivity and just focused on the environment. Present study was aimed to establish an ultra-sensitive and simple method based on good quality monoclonal antibody, applying to evaluate excretion level of DBP in urine samples of Chinese population directly. A monoclonal antibody was generated and characterized after fusion of myeloma cells with spleen cells isolated from BALB/c mouse. The mouse was previously immunized using a specially designed amino derivative of DBP conjugated with bovine serum albumin (BSA) as immunogen. Cross-reactivity values of the monoclonal antibody against DBP, di-isobutyl phthalate (DIBP) were observed 100% and 1.25%, while for dimethyl phthalate (DMP), butyl benzyl phthalate (BBP) and didecyl phthalate (DDP) the values were < 0.06%. The standard curve was constructed at 0–50 ng mL{sup −1} and good linearity (R{sup 2} = 0.994) was achieved. The observed IC{sub 50} (7.34 ng mL{sup −1}) and LOD (0.06 ng mL{sup −1}) values was improved 1000-fold to polyclonal antibody and 5-fold to other monoclonal antibodies. A total 1246 urine samples were analyzed and the detection frequency of DBP was observed 72.87% by ic-ELISA. The 95th percentile and mean concentration of DBP were 12.07 and 3.00 ng mL{sup −1}. Acceptable recovery rates of DBP were 97.8–114.3% and coefficients variation 5.93–11.09%. The concentrations of DBP in females were found significantly higher (p < 0.05) than males. Similarly, the DBP in middle aged and low educated individuals was found higher (p < 0.001) than the others. Considering the adverse health effects, DBP internal exposure in the Chinese population should be reduced. The ic-ELISA method has been proved as a cost effective, specific, and highly sensitive screening

  11. A Refined Zigzag Beam Theory for Composite and Sandwich Beams

    Science.gov (United States)

    Tessler, Alexander; Sciuva, Marco Di; Gherlone, Marco

    2009-01-01

    A new refined theory for laminated composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse-shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. Exact solutions for simply supported and cantilevered beams subjected to static loads are derived and the improved modelling capability of the new zigzag beam theory is demonstrated. In particular, extensive results for thick beams with highly heterogeneous material lay-ups are discussed and compared with corresponding results obtained from elasticity solutions, two other zigzag theories, and high-fidelity finite element analyses. Comparisons with the baseline Timoshenko Beam Theory are also presented. The comparisons clearly show the improved accuracy of the new, refined zigzag theory presented herein over similar existing theories. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining relatively low-cost, accurate estimates of structural response needed to design an important class of high-performance aerospace structures.

  12. Experimental investigation on sandwich structure ring-type ultrasonic motor.

    Science.gov (United States)

    Peng, Taijiang; Shi, Hongyan; Liang, Xiong; Luo, Feng; Wu, Xiaoyu

    2015-02-01

    This paper presents a manufacture method for a sandwich structure Ultrasonic Motor (USM) and experiment. Two pieces of rotor clamped on a stator, and a stainless steel disk-spring is bonded on the hollow rotor disk to provide the press by a nut assembled on the shaft. The stator is made of a double-side Printed-Circuit Board (PCB) which is sawed out the ring in the center and connected on the board with three legs. On each side of the ring surface, there are electrodes connected at the same position via through hole. The three layer drive circuit for sine, cosine, and ground signal is connected on the board through each leg. There are many piezoelectric components (PZT) bonded between two electrodes and fill soldering tin on each electrode. Then PZT is welded on PCB by reflow soldering. Finally, rub the gibbous soldering tin down to the position of PZT surface makes sure the surface contacts with rotor evenly. The welding process can also be completed by Surface Mounted Technology (SMT). A prototype motor is manufactured by this method. Two B03 model shapes of the stator are obtained by the finite element analysis and the optimal frequency of the motor is 56.375 kHz measured by impedance instrument. The theoretical analysis is conducted for the relationship between the revolving speed of the USM and thickness of stator ring, number of the travelling waves, PZT amplitude, frequency and the other parameters. The experiment result shows that the maximum revolving speed is 116 RPM and the maximum torque is 25 N mm, when the actuate voltage is 200 VAC. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. The evaluation of CLIA, RIA and MSP-ELISA for measurement of thyroid hormones

    International Nuclear Information System (INIS)

    Jing Hua; Li Dan; Chen Yiguang; Zhou Huiqin; Xu Liyan

    2005-01-01

    To compare the characteristics of chemiluminescent immunoassay (CLIA), RIA and magnetic solid phase enzyme-linked immnosorbent assay (MSP-ELISA) in measuring thyroid hormones, TT 3 , TT 4 , FT 3 , FT 4 and TSH were tested in 40 samples of human serum and in standard samples of thyroid hormones by CLIA, RIA and MSP-ELISA respectively. The linearity, relativiy, precision, recovery of these three met hods were compared. The result showed that there were no statistical differences between CLIA, RIA and MSP-ELISA in linearity and relativity. CLIA was better than RIA and MSP-ELISA in precision and accuracy. (authors)

  14. A multi-purpose ultrasonic streaming mixer for integrated magnetic bead ELISAs

    International Nuclear Information System (INIS)

    Brandhoff, Lukas; Lang, Walter; Vellekoop, Michael J; Zirath, Helene; Peham, Johannes; Wiesinger-Mayr, Herbert; Salas, Mariugenia; Haller, Anna; Spittler, Andreas; Schnetz, Guntram

    2015-01-01

    We present an ultrasonic streaming mixer for disposable and on-chip magnetic bead ELISAs. The ultrasonic transducer is placed at system-level to keep cost per chip as low as possible, and is coupled to the chip by means of a solid ultrasonic horn. The system provides mixing of liquids, as well as dispersion of the superparamagnetic beads in the ELISA. Additionally it can be used clean the chamber surface from nonspecifically bound proteins during the washing steps in the ELISA protocol. Using our system the time for the ELISA protocol has been greatly reduced down to 30 min. (paper)

  15. Prospects of eLISA for Detecting Galactic Binary Black Holes Similar to GW150914

    OpenAIRE

    Seto, Naoki

    2016-01-01

    We discuss the prospects of eLISA for detecting gravitational waves (GWs) from Galactic binary black holes (BBHs) similar to GW150914. For a comoving merger rate that is consistent with current observation, eLISA is likely to identify at least one BBH with a sufficient signal-to-noise ratio. In addition, eLISA has a potential to measure the eccentricity of the BBH as small as $e\\sim 0.02$, corresponding to the residual value $e\\sim 10^{-6}$ at 10Hz. Therefore, eLISA could provide us with a cr...

  16. Therapeutic Results of Radiotherapy in Rectal Carcinoma -Comparison of Sandwich Technique Radiotherapy with Postoperative Radiotherapy

    International Nuclear Information System (INIS)

    Huh, Gil Cha; Suh, Hyun Suk; Lee, Hyuk Sang; Kim, Re Hwe; Kim, Chul Soo; Kim, Hong Yong; Kim, Sung Rok

    1996-01-01

    Purpose : To evaluate the potential advantage for 'sandwich' technique radiotherapy compared to postoperative radiotherapy in respectable rectal cancer. Between January 1989 and May 1994, 60 patients with respectable rectal cancer were treated at Inje University Seoul and Sanggye Paik Hospital.Fifty one patients were available for analysis : 20 patients were treated with sandwich technique radiotherapy and 31 patients were treated with postoperative radiotherapy. In sandwich technique radiotherapy(RT), patients were treated with preoperative RT 1500 cGy/5fx followed by immediate curative resection. Patients staged as Astler-Coller B2, C were considered for postoperative RT with 2500-4500 cGy. In postoperative RT, total radiation dose of 4500-6120 cGy, 180 cGy daily at 4-6 weeks was delivered. Patients were followed for median period of 25 months. Results : The overall 5-year survival rates for sandwich technique RT group and postoperative RT group were 60% and 71%, respectively(p>0.05). The 5-year disease free survival rates for each group were 63%. There was no difference in local failure rate between two groups(11% versus 7%). Incidence of distant metastasis was 11%(2/20) in the sandwich technique RT group and 20%(6/31) in the postoperative RT group(p>0.05). The frequencies of acute and chronic complications were comparable in both groups. Conclusion : The sandwich technique radiotherapy group shows local recurrence and survival similar to those of postoperative RT alone group but reduced distant metastasis compared to postoperative RT group. But long term follow-up and large number of patients is needed to make an any firm conclusion regarding the value of this sandwich technique RT

  17. Density functional study of isoguanine tetrad and pentad sandwich complexes with alkali metal ions.

    Science.gov (United States)

    Meyer, Michael; Steinke, Thomas; Sühnel, Jürgen

    2007-02-01

    Isoguanine tetraplexes and pentaplexes contain two or more stacked polyads with intercalating metal ions. We report here the results of a density functional study of sandwiched isoguanine tetrad and pentad complexes consisting of two polyads with Na(+), K(+) and Rb(+) ions at the B3LYP level. In comparison to single polyad metal ion complexes, there is a trend towards increased non-planarity of the polyads in the sandwich complexes. In general, the pentad sandwiches have relatively planar polyad structures, whereas the tetrad complexes contain highly non-planar polyad building blocks. As in other sandwich complexes and in metal ion complexes with single polyads, the metal ion-base interaction energy plays an essential role. In iG sandwich structures, this interaction energy is slightly larger than in the corresponding guanine sandwich complexes. Because the base-base interaction energy is even more increased in passing from guanine to isoguanine, the isoguanine sandwiches are thus far the only examples where the base-base interaction energy is larger than the base-metal ion interaction energy. Stacking interactions have been studied in smaller models consisting of two bases, retaining the geometry from the complete complex structures. From the data obtained at the B3LYP and BH&H levels and with Møller-Plesset perturbation theory, one can conclude that the B3LYP method overestimates the repulsion in stacked base dimers. For the complexes studied in this work, this is only of minor importance because the direct inter-tetrad or inter-pentad interaction is supplemented by a strong metal ion-base interaction. Using a microsolvation model, the metal ion preference K(+) approximately Rb(+) > Na(+) is found for tetrad complexes. On the other hand, for pentads the ordering is Rb(+) > K(+) > Na(+). In the latter case experimental data are available that agree with this prediction.

  18. Interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device – Numerical modelling

    DEFF Research Database (Denmark)

    Martakos, G.; Andreasen, J.H.; Berggreen, Christian

    2017-01-01

    A novel crack arresting device is implemented in foam-cored composite sandwich beams and tested using the Sandwich Tear Test (STT) configuration. A finite element model of the setup is developed, and the predictions are correlated with observations and results from a recently conducted experiment...... concept, as well as a design tool that can be used for the implementation of crack arresting devises in engineering applications of sandwich components and structures....

  19. Insert Design and Manufacturing for Foam-Core Composite Sandwich Structures

    Science.gov (United States)

    Lares, Alan

    Sandwich structures have been used in the aerospace industry for many years. The high strength to weight ratios that are possible with sandwich constructions makes them desirable for airframe applications. While sandwich structures are effective at handling distributed loads such as aerodynamic forces, they are prone to damage from concentrated loads at joints or due to impact. This is due to the relatively thin face-sheets and soft core materials typically found in sandwich structures. Carleton University's Uninhabited Aerial Vehicle (UAV) Project Team has designed and manufactured a UAV (GeoSury II Prototype) which features an all composite sandwich structure fuselage structure. The purpose of the aircraft is to conduct geomagnetic surveys. The GeoSury II Prototype serves as the test bed for many areas of research in advancing UAV technologies. Those areas of research include: low cost composite materials manufacturing, geomagnetic data acquisition, obstacle detection, autonomous operations and magnetic signature control. In this thesis work a methodology for designing and manufacturing inserts for foam-core sandwich structures was developed. The results of this research work enables a designer wishing to design a foam-core sandwich airframe structure, a means of quickly manufacturing optimized inserts for the safe introduction of discrete loads into the airframe. The previous GeoSury II Prototype insert designs (v.1 & v.2) were performance tested to establish a benchmark with which to compare future insert designs. Several designs and materials were considered for the new v.3 inserts. A plug and sleeve design was selected, due to its ability to effectively transfer the required loads to the sandwich structure. The insert material was chosen to be epoxy, reinforced with chopped carbon fibre. This material was chosen for its combination of strength, low mass and also compatibility with the face-sheet material. The v.3 insert assembly is 60% lighter than the

  20. Viewpoints of working sandwich generation women and occupational therapists on role balance strategies.

    Science.gov (United States)

    Evans, Kiah L; Girdler, Sonya J; Falkmer, Torbjorn; Richmond, Janet E; Wagman, Petra; Millsteed, Jeannine; Falkmer, Marita

    2017-09-01

    Occupational therapists need to be cognizant of evidence-based role balance advice and strategies that women with multigenerational caring responsibilities can implement independently or with minimal assistance, as role balance may not be the primary goal during many encounters with this population. Hence, this study aimed to identify the viewpoints on the most helpful role balance strategies for working sandwich generation women, both from their own perspectives and from the perspective of occupational therapists. This was achieved through a Q methodology study, where 54 statements were based on findings from interviews, sandwich generation literature and occupational therapy literature. In total, 31 working sandwich generation women and 42 occupational therapists completed the Q sort through either online or paper administration. The data were analysed using factor analysis with varimax rotation and were interpreted through collaboration with experts in the field. The findings revealed similarities between working sandwich generation women and occupational therapists, particularly in terms of advocating strategies related to sleep, rest and seeking practical assistance from support networks. Differences were also present, with working sandwich generation women viewpoints tending to emphasize strategies related to coping with a busy lifestyle attending to multiple responsibilities. In contrast, occupational therapy viewpoints prioritized strategies related to the occupational therapy process, such as goal setting, activity focused interventions, monitoring progress and facilitating sustainable outcomes.

  1. Analysis of Stainless Steel Sandwich Panels with a Metal Foam Care for Lightweight Fan Blade Design

    Science.gov (United States)

    Min, James B.; Ghosn, Louis J.; Lerch, Bradley A.; Raj, Sai V.; Holland, Frederic A., Jr.; Hebsur, Mohan G.

    2004-01-01

    The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. Traditionally, these components have been fabricated using expensive materials such as light weight titanium alloys, polymeric composite materials and carbon-carbon composites. The present study investigates the use of P sandwich foam fan blade made up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The stiffness of the sandwich structure is increased by separating the two face sheets by a foam core. The resulting structure possesses a high stiffness while being lighter than a similar solid construction. Since the face sheets carry the applied bending loads, the sandwich architecture is a viable engineering concept. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of the sandwich structure for a fan blade application. A vibration analysis for natural frequencies and P detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of skin thickness and core volume %re presented with a comparison to a solid titanium blade.

  2. Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

    International Nuclear Information System (INIS)

    Lin Shuyu; Tian Hua

    2008-01-01

    A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

  3. Flexural wave attenuation in a sandwich beam with viscoelastic periodic cores

    Science.gov (United States)

    Guo, Zhiwei; Sheng, Meiping; Pan, Jie

    2017-07-01

    The flexural-wave attenuation performance of traditional constraint-layer damping in a sandwich beam is improved by using periodic constrained-layer damping (PCLD), where the monolithic viscoelastic core is replaced with two periodically alternating viscoelastic cores. Closed-form solutions of the wave propagation constants of the infinite periodic sandwich beam and the forced response of the corresponding finite sandwich structure are theoretically derived, providing computational support on the analysis of attenuation characteristics. In a sandwich beam with PCLD, the flexural waves can be attenuated by both Bragg scattering effect and damping effect, where the attenuation level is mainly dominated by Bragg scattering in the band-gaps and by damping in the pass-bands. Affected by these two effects, when the parameters of periodic cores are properly selected, a sandwich beam with PCLD can effectively reduce vibrations of much lower frequencies than that with traditional constrained-layer damping. The effects of the parameters of viscoelastic periodic cores on band-gap properties are also discussed, showing that the average attenuation in the desired frequency band can be maximized by tuning the length ratio and core thickness to proper values. The research in this paper could possibly provide useful information for the researches and engineers to design damping structures.

  4. Effect of Different Concentration of Sodium Hydroxide [NaOH] on Kenaf Sandwich Structures

    Science.gov (United States)

    Aziz, M.; Halim, Z.; Othman, M.

    2018-01-01

    Sandwich panels are structures that made of three layers, low-density core inserted in between thin skin layers. This structures allow the achievement of excellent mechanical performance with low weight, thus this characteristic fulfil requirement to be use in aircraft application. In recent time, sandwich structures have been studied due to it has multifunction properties and lightweight. The aim of this study is to fabricate a composite sandwich structures with biodegradable material for face sheet [skin] where the fibre being treat with different concentration of sodium hydroxide [NaOH] with 10 and 20 hours of soaking time. Kenaf fibre [treated] reinforced epoxy will be used as skins and Nomex honeycomb is chosen to perform as core for this sandwich composite structure. The mechanical properties that are evaluated such as flexural strength and impact energy of kenaf fibre-reinforced epoxy sandwich structures. For flexural test, the optimum flexural strength is 13.4 MPa and impact strength is 18.3 J.

  5. A Study on Flexural Properties of Sandwich Structures with Fiber/Metal Laminate Face Sheets

    Science.gov (United States)

    Dariushi, S.; Sadighi, M.

    2013-10-01

    In this work, a new family of sandwich structures with fiber metal laminate (FML) faces is investigated. FMLs have benefits over both metal and fiber reinforced composites. To investigate the bending properties of sandwich beams with FML faces and compare with similar sandwich beams with fibrous composite faces, 6 groups of specimen with different layer arrangements were made and tested. Results show that FML faces have good resistance against transverse local loads and minimize stress concentration and local deformations of skin and core under the loading tip. In addition, FML faces have a good integrity even after plateau region of foam cores and prevent from catastrophic failures, which cannot be seen in fibrous composite faces. Also, FML faces are lighter than metal faces and have better connection with foam cores. Sandwich beams with FML faces have a larger elastic region because of simultaneous deformation of top and bottom faces and larger failure strain thanks to good durability of FMLs. A geometrical nonlinear classical theory is used to predict force-deflection behavior. In this model an explicit formula between symmetrical sandwich beams deflections and applied force which can be useful for designers, is derived. Good agreement is obtained between the analytical predictions and experimental results. Also, analytical results are compared with small deformation solution in a parametric study, and the effects of geometric parameters on difference between linear and nonlinear results are discussed.

  6. ANALISA TEKNIS DAN EKONOMIS PENGGUNAAN COREMAT UNTUK KONSTRUKSI FRP (FIBERGLASS REINFORCED PLASTIC SANDWICH PADA BADAN KAPAL

    Directory of Open Access Journals (Sweden)

    Parlindungan Manik

    2012-04-01

    Full Text Available Planning of ship construction is make its having good effectivity value and efficiency. Composite as material alternative to changes of steel feedstock and wood has many applied named FRP (fiberglass reinforced plastics single skin. The weakness of this FRP was heavy construction and requires many production time. Therefore, will be checked comparison between single skin with sandwich constructions for shell. In this research, the way for making composite is hand lay up method with three various thickness of skin there are : t, t/2, and t/4. To know strength comparison from the various skin of sandwich with single skin, must be test, consist of tensile test.. The result is analyzed then compared by BKI (Biro Klasifikasi Indonesia rules for the fiberglass ship. Based on the result, indicates that optimization skin thickness of sandwich construction applies Coremat which tensile strength it is equivalent with Single Skin at 2/3t and usage of Sandwich construction causes 23,12 % lighter. In economic analyze, advantage from low weight is compensation of addition 23,12 % DWT. Material cost for Sandwich about 11,35% bigger than Single Skin construction.

  7. ANALISA TEKNIS DAN EKONOMIS PENGGUNAAN COREMAT UNTUK KONSTRUKSI FRP (FIBERGLASS REINFORCED PLASTIC SANDWICH PADA BADAN KAPAL

    Directory of Open Access Journals (Sweden)

    Parlindungan Manik

    2012-02-01

    Full Text Available Planning of ship construction is make its having good effectivity value and efficiency. Composite as materialalternative to changes of steel feedstock and wood has many applied named FRP (fiberglass reinforcedplastics single skin. The weakness of this FRP was heavy construction and requires many production time.Therefore, will be checked comparison between single skin with sandwich constructions for shell.In this research, the way for making composite is hand lay up method with three various thickness of skinthere are : t, t/2, and t/4. To know strength comparison from the various skin of sandwich with single skin,must be test, consist of tensile test.. The result is analyzed then compared by BKI (Biro Klasifikasi Indonesiarules for the fiberglass ship.Based on the result, indicates that optimization skin thickness of sandwich construction applies Corematwhich tensile strength it is equivalent with Single Skin at 2/3t and usage of Sandwich construction causes23,12 % lighter. In economic analyze, advantage from low weight is compensation of addition 23,12 % DWT.Material cost for Sandwich about 11,35% bigger than Single Skin construction.

  8. Ageing tests study on wood-based sandwich panels

    Directory of Open Access Journals (Sweden)

    Mateo, Raquel

    2011-12-01

    Full Text Available Composite lightweight wood panels are being increasingly used in construction in Spain. Their growing use should be accompanied by necessary guarantees based on studies of their properties. As it is prescriptive and in addition to others tests, in the present work is examinated the durability of these panels when exposed to the climatic conditions, a characteristic of great importance for wood products, according to Guide ETAG 016, the current standard defining the ageing tests to be used. However, due to the use class of this material, there are indications that the testing outlined in this Guide is inappropriate for assessing the ageing of wood-based sandwich panels. Alternative tests are here proposed that recreate rather better the real conditions under which these products are used. Covering the samples in a waterproof sheeting permeable to the outward movement of water vapour, which is in fact used in the installation, provided the best procedure for testing these panels.

    Los paneles sándwich de madera son un producto de creciente aplicación en la edificación de nuestro país. Este ascendente uso del material debe estar acompañado de las garantías necesarias avaladas por un estudio previo de sus prestaciones. Como es preceptivo y entre otros, se evalúa su durabilidad frente a las condiciones climatológicas, clave en los productos derivados de la madera, acorde a la normativa actual definida con tal fin, la Guía ETAG 016. Sin embargo, debido a la clase de uso del material, se ha detectado que dicha normativa tal y como está concebida no es capaz de valorar su envejecimiento adecuadamente. En este trabajo se proponen ensayos alternativos al establecido tras exhaustivos análisis que recrean las condiciones reales de uso y más acordes a los productos de madera. Se concluye que la incorporación de una lámina impermeable pero permeable al vapor de agua hacia el exterior, como las utilizadas en el montaje, aportan el mejor

  9. Development of monoclonal-antibody-based products for medical research and diagnostic imaging. Technical report, 28 January 1987-31 December 1988 (Final)

    International Nuclear Information System (INIS)

    Rhodes, B.A.; Pant, K.D.; Chauhan, N.; Buckelew, J.; Budd, P.

    1989-04-01

    Two major areas of application of monoclonal antibodies were examined: the development of products to support the 'Antibody Delivery System', a parent-specific and variable antibody formula drug system for use in imaging and treatment of cancer, and the development of an antibody-based radiopharmaceutical for imaging occult abscesses and other conditions involving high concentrations of white blood cells. In development of the Antibody Delivery System components, methods for characterization and purification of monoclonal antibodies were developed and validated; a dot immunoassay test, under the name RhoDot (TM) Immunoassay, was developed for matching antibodies to putative tumor specimen: a radioimmunoassay, under the name PhoChek (TM) Quality Control Test Kit for Radiolabeled Antibodies, was developed and commercialized for measuring the immunoreactive fraction of radiolabeled antibodies specific to colorecal cancer; and a patient-specific quality control test was developed. In development of the antibody-based radiopharmaceutical for imaging occult abscesses, a candidate antibody was identified and produced under U.S. Food and Drug Administration standards preparatory to human clinical trials

  10. Undergraduate Laboratory Module for Implementing ELISA on the High Performance Microfluidic Platform

    Science.gov (United States)

    Giri, Basant; Peesara, Ravichander R.; Yanagisawa, Naoki; Dutta, Debashis

    2015-01-01

    Implementing enzyme-linked immunosorbent assays (ELISA) in microchannels offers several advantages over its traditional microtiter plate-based format, including a reduced sample volume requirement, shorter incubation period, and greater sensitivity. Moreover, microfluidic ELISA platforms are inexpensive to fabricate and allow integration of…

  11. Elisa ja EMT kemplevad, kumb pakub paremat levi / Toivo Tänavsuu

    Index Scriptorium Estoniae

    Tänavsuu, Toivo

    2007-01-01

    Mobiilifirma Elisa väitel on Tartus kõige kvaliteetsem leviala Elisal. EMT võrgujuhi Margus Malvi hinnangul on EMT ja Elisa võrgud Tartus samaväärsed, ainus erinevus on kliendi kaugus tugijaamast. Lisa: Mobiililevi kvaliteet

  12. Early antihepatitis C virus response with second-generation C200/C22 ELISA

    NARCIS (Netherlands)

    van der Poel, C. L.; Bresters, D.; Reesink, H. W.; Plaisier, A. A.; Schaasberg, W.; Leentvaar-Kuypers, A.; Choo, Q. L.; Quan, S.; Polito, A.; Houghton, M.

    1992-01-01

    Detection of early antibody to hepatitis C virus (HCV) by a new second-generation C200/C22 anti-HCV enzyme-linked immunosorbent assay (ELISA) and a four-antigen recombinant immunoblot assay (4-RIBA) was compared with the first-generation anti-HCV C100 ELISA using sequential serum samples of 9

  13. EMT nurjas Rate.ee ostuga Elisa kõnekaardiplaani / Gert D. Hankewitz

    Index Scriptorium Estoniae

    Hankewitz, Gert D.

    2006-01-01

    Ilmunud ka: Delovõje Vedomosti 12. apr. lk. 2. Elisa juhatuse esimehe Sami Seppäneni sõnul ostis EMT suhtlusportaali Rate.ee, kuna sai teada, et Elisa ning portaal plaanivad koos uue kõnekaardi turule tuua

  14. ANALYSIS OF SOIL AND DUST SAMPLES FOR POLYCHLORINATED BIPHENYLS BY ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA)

    Science.gov (United States)

    An inhibition enzyme-linked immunosorbent assay (ELISA) was used to determine polychlorinated biphenyls (PCBs) in house dust and soil. Soil and house dust samples were analyzed for PCB by both gas chromatography/electron capture detection (GC/ECD) and ELISA methods. A correlati...

  15. Evaluation of CSFV Antibody ELISAs for the differentiation of infected from vacci-nated animals

    DEFF Research Database (Denmark)

    Schroeder, Sabine; Blome, Sandra; Koenen, Frank

    countries and out-breaks occurred recently e.g. in Germany, France, Hungary, Romania, Bulgaria, and the Slovak Republic. Preventive vaccination is prohibited within the EU, but emergency vaccination can be part of the strategy in case of a contingency. Using conventional vaccines, differentiation...... of vaccinated from infected animals (DIVA) is not possible. Newly developed modified live marker vaccines allow a DIVA strategy based on the use of enzyme linked immunosorbent assay (ELISA) tests. The aim of this study was to evaluate CSF virus (CSFV) Antibody ELISAs, com-mercially available in Europe......, for their diagnostic sensitivity as well as for their potential in differentiating between infected and marker vaccinated animals. Two newly available ELISAs were included into the tests, the Priocheck® CSFV Erns ELISA, a special DIVA test, and the LDL Pigtype® CSFV Antibody ELISA. An inter-laboratory comparison test...

  16. Cystatin capture elisa immunodiagnosis of human fasciolosis at Chupaca-Junin Province

    International Nuclear Information System (INIS)

    Cornejo, W.; Alva, P.; Sevilla, C.; Huiza, A.; Universidad Nacional Mayor de San Marcos, Lima

    2003-01-01

    To determine the prevalence of human fasciolosis in an endemic area by means of an Enzyme-Linked Immunosorbent Assay (ELISA) using cystatin as a capture agent for the detection of specific antibodies to fasciola hepatica cysteine proteinases. An ELISA plate was sensitized with cystatin, incubated with excretory-secretory products of adult flukes, and followed by standard ELISA procedures. Clinical applicability of the cystatin capture ELISA for the immunodiagnosis of fasciolosis was tested with 200 serum samples of children and adults from an endemic area in Chupaca province, Junin department. Serum samples from the endemic area tested by cystatin capture ELISA showed 27/200 (13,5%) of positive cases. Fasciolosis remains a major health problem at Chupaca province, Junin department

  17. Evaluation of the Impact Resistance of Various Composite Sandwich Beams by Vibration Tests

    Directory of Open Access Journals (Sweden)

    Amir Shahdin

    2011-01-01

    Full Text Available Impact resistance of different types of composite sandwich beams is evaluated by studying vibration response changes (natural frequency and damping ratio. This experimental works will help aerospace structural engineer in assess structural integrity using classification of impact resistance of various composite sandwich beams (entangled carbon and glass fibers, honeycomb and foam cores. Low velocity impacts are done below the barely visible impact damage (BVID limit in order to detect damage by vibration testing that is hardly visible on the surface. Experimental tests are done using both burst random and sine dwell testing in order to have a better confidence level on the extracted modal parameters. Results show that the entangled sandwich beams have a better resistance against impact as compared to classical core materials.

  18. Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure

    Directory of Open Access Journals (Sweden)

    Liying Jiang

    2011-12-01

    Full Text Available In this work, the problem of a curved functionally graded piezoelectric (FGP actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

  19. Fatigue Debond Growth in Sandwich Structures Loaded in Mixed Mode Bending (MMB)

    DEFF Research Database (Denmark)

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

    2008-01-01

    Static and cyclic debond growth in sandwich specimens loaded in mixed mode bending (MMB) is examined. The MMB sandwich specimens were manufactured using H100 PVC foam core and E-glass/polyester non-crimp quadro-axial [0/45/90/-45]s DBLT-850 face sheets. Static test were performed to determine...... the fracture toughness of the debonded sandwich specimens at different mixed mode loadings. The mixed mode ratio (mode I to mode II) was controlled by changing the lever arm distance of the MMB test rig. Compliance technique and visual inspection was employed to measure the crack length during fatigue. Fatigue...... tests were performed at 90% of the static fracture toughness at a loading ratio of R=0.1. Fatigue results revealed higher debond crack growth rates when the lever arm distance was increased. For some specimens, the crack propagated just below the face/core interface in the foam core and for others...

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

    International Nuclear Information System (INIS)

    Camarda, C.J.; Basiulis, A.

    1983-08-01

    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. Compressive and bending behavior of sandwich panels with Octet truss core fabricated from wires

    International Nuclear Information System (INIS)

    Lim, Ji Hyun; Nah, Seong Jun; Kang, Ki Ju; Koo, Man Hoe

    2005-01-01

    Ultra light metal structures have been studied for several years because of their superior specific stiffness, strength and potential of multi functions. Many studies have been focused on how to manufacture ultra light metal structures and optimize them. In this study, we introduced a new idea to make sandwich panels having Octet truss cores. Wires bent in a shape of triangular wave were assembled to construct an Octet truss core and it was bonded with two face sheets to be a sandwich panel. The bending and compressive strength and stiffness were estimated through elementary mechanics for the sandwich specimens with two kinds of face sheets and the results were compared with the ones measured by experiments. Some aspects of assembling and mechanical behavior were discussed compared with Kagome core fabricated from wire, which had been introduced in the authors' previous work

  2. Face/core interface fracture characterization of mixed mode bending sandwich specimens

    DEFF Research Database (Denmark)

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

    2011-01-01

    and PVC H45, H100 and H250 foam core materials were evaluated. A methodology to perform precracking on fracture specimens in order to achieve a sharp and representative crack front is outlined. The mixed mode loading was controlled in the mixed mode bending (MMB) test rig by changing the loading......Debonding of the core from the face sheets is a critical failure mode in sandwich structures. This paper presents an experimental study on face/core debond fracture of foam core sandwich specimens under a wide range of mixed mode loading conditions. Sandwich beams with E‐glass fibre face sheets...... application point (lever arm distance). Finite element analysis was performed to determine the mode‐mixity at the crack tip. The results showed that the face/core interface fracture toughness increased with increased mode II loading. Post failure analysis of the fractured specimens revealed that the crack...

  3. Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure.

    Science.gov (United States)

    Yan, Zhi; Zaman, Mostafa; Jiang, Liying

    2011-12-12

    In this work, the problem of a curved functionally graded piezoelectric (FGP) actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g 31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

  4. Optimal design of sandwich ribbed flat baffle plates of a circular cylindrical tank

    International Nuclear Information System (INIS)

    Malinowski, Marek; Magnucki, Krzysztof

    2005-01-01

    The subject of this paper is a sandwich ribbed flat baffle plate of a circular cylindrical tank. The paper deals with a problem of optimal thickness of this construction with a soft core. The construction is distinguished by a local axisymmetric pre-springing. The mathematical description is based on the theory of shells with analysis of disturbance of the stress membrane state. The sandwich ribbed flat baffle plate divides the tank into two chambers. One of them is loaded by uniform pressure, while the other is empty and unloaded. Dimensions of ribs, faces and the entire baffle plate have been determined with a view to minimize the mass under strength constraints. The effect of optimal thickness of this sandwich plate has been examined by means of the finite element method

  5. Performance improvement of organic thin film transistors by using active layer with sandwich structure

    Science.gov (United States)

    Ni, Yao; Zhou, Jianlin; Kuang, Peng; Lin, Hui; Gan, Ping; Hu, Shengdong; Lin, Zhi

    2017-08-01

    We report organic thin film transistors (OTFTs) with pentacene/fluorinated copper phthalo-cyanine (F16CuPc)/pentacene (PFP) sandwich configuration as active layers. The sandwich devices not only show hole mobility enhancement but also present a well control about threshold voltage and off-state current. By investigating various characteristics, including current-voltage hysteresis, organic film morphology, capacitance-voltage curve and resistance variation of active layers carefully, it has been found the performance improvement is mainly attributed to the low carrier traps and the higher conductivity of the sandwich active layer due to the additional induced carriers in F16CuPc/pentacene. Therefore, using proper multiple active layer is an effective way to gain high performance OTFTs.

  6. Self-healing sandwich structures incorporating an interfacial layer with vascular network

    International Nuclear Information System (INIS)

    Chen, Chunlin; Peters, Kara; Li, Yulong

    2013-01-01

    A self-healing capability specifically targeted for sandwich composite laminates based on interfacial layers with built-in vascular networks is presented. The self-healing occurs at the facesheet–core interface through an additional interfacial layer to seal facesheet cracks and rebond facesheet–core regions. The efficacy of introducing the self-healing system at the facesheet–core interface is evaluated through four-point bend and edgewise compression testing of representative foam core sandwich composite specimens with impact induced damage. The self-healing interfacial layer partially restored the specific initial stiffness, doubling the residual initial stiffness as compared to the control specimen after the impact event. The restoration of the ultimate specific skin strength was less successful. The results also highlight the critical challenge in self-healing of sandwich composites, which is to rebond facesheets which have separated from the core material. (paper)

  7. Numerical simulation of the hole-flanging process for steel-polymer sandwich sheets

    Science.gov (United States)

    Griesel, Dominic; Keller, Marco C.; Groche, Peter

    2018-05-01

    In light of increasing demand for lightweight structures, hybrid materials are frequently used in load-optimized parts. Sandwich structures like metal-polymer sandwich sheets provide equal bending stiffness as their monolithic counterparts at a drastically reduced weight. In addition, sandwich sheets have noise-damping properties, thus they are well-suited for a large variety of parts, e.g. façade and car body panels, but also load-carrying components. However, due to the creep tendency and low heat resistance of the polymer cores, conventional joining technologies are only applicable to a limited degree. Through hole-flanging it is possible to create branches in sandwich sheets to be used as reinforced joints. While it is state of the art for monolithic materials, hole-flanging of sandwich sheets has not been investigated yet. In order to simulate this process for different material combinations and tool geometries, an axisymmetric model has been developed in the FE software Abaqus/CAE. In the present paper, various modeling strategies for steel-polymer sandwich sheets are examined, including volume elements, shell elements and combinations thereof. Different methods for joining the distinct layers in the FE model are discussed. By comparison with CT scans and optical 3D measurements of experimentally produced hole-flanges, the feasibility of the presented models is evaluated. Although a good agreement of the numerical and experimental results has been achieved, it becomes clear that the classical forming limit diagram (FLD) does not adequately predict failure of the steel skins.

  8. 3D FDM production and mechanical behavior of polymeric sandwich specimens embedding classical and honeycomb cores

    Science.gov (United States)

    Brischetto, Salvatore; Ferro, Carlo Giovanni; Torre, Roberto; Maggiore, Paolo

    2018-04-01

    Desktop 3D FDM (Fused Deposition Modelling) printers are usually employed for the production of nonstructural objects. In recent years, the present authors tried to use this technology also to produce structural elements employed in the construction of small UAVs (Unmanned Aerial Vehicles). Mechanical stresses are not excessive for small multirotor UAVs. Therefore, the FDM technique combined with polymers, such as the ABS (Acrylonitrile Butadiene Styrene) and the PLA(Poly Lactic Acid), can be successfully employed to produce structural components. The present new work is devoted to the production and preliminary structural analysis of sandwich configurations. These new lamination schemes could lead to an important weight reduction without significant decreases of mechanical properties. Therefore, it could be possible, for the designed application (e.g., a multifunctional small UAV produced via FDM), to have stiffener and lighter structures easy to be manufactured with a low-cost 3D printer. The new sandwich specimens here proposed are PLA sandwich specimens embedding a PLA honeycomb core produced by means of the same extruder, multilayered specimens with ABS external layers and an internal homogeneous PLA core using different extruders for the two materials, sandwich specimens with external ABS skins and an internal PLA honeycomb core using different extruders for the two materials, and sandwich specimens where two different extruders have been employed for PLA material used for skins and for the internal honeycomb core. For all the proposed configurations, a detailed description of the production activity is given.Moreover, several preliminary results about three-point bending tests, different mechanical behaviors and relative delamination problems for each sandwich configuration will be discussed in depth.

  9. On the use of a woven mat to control the crack path in composite sandwich structures

    DEFF Research Database (Denmark)

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

    2008-01-01

    tractionsbetween the separated crack surfaces [4, 5]. The outline of a crack propagating under large scale bridging in a sandwich structure can be seen in Figure 1. The fiber bridging mechanism possesses an increased potential damage tolerance capacity for the sandwich structure if it can be predicatively....... The sign of the moment ratio can be reversed by changing the mounting direction of the wire. If moments with opposite signs are applied e.g. M1/M2 = -1, crack opening in the normal direction is dominating (mode I). If moments with the same sign are applied the crack opening in the tangential direction...

  10. Effect of a magnetic field on the excess resistance of SNS sandwiches

    International Nuclear Information System (INIS)

    Logvenov, G.Y.; Ryazanov, V.V.

    1983-01-01

    The contribution of superconducting plates to the resistance of Ta--Cu--Ta sandwiches in the presence of a magnetic field of up to 170 Ge is investigated. Near the superconducting transition temperature T/sub c/H, the Ta used was in a mixed (vortical) state. It is shown that the presence of gradients of the order parameter near the Abrikosov vortices appreciably changes the penetration depth of a longitudinal electric field into the superconductor and leads to a corresponding change in the excess resistance of SNS sandwiches

  11. Thermal performance of capillary micro tubes integrated into the sandwich element made of concrete

    DEFF Research Database (Denmark)

    Mikeska, Tomas; Svendsen, Svend

    2013-01-01

    integrated into the thin plate of sandwich element made of HPC can supply the energy needed for heating and cooling. The investigations were conceived as a low temperature concept, where the difference between the temperature of circulating fluid and air in the room was kept in range of 1 to 4°C. © (2013......The thermal performance of radiant heating and cooling systems (RHCS) composed of capillary micro tubes (CMT) integrated into the inner plate of sandwich elements made of High Performance Concrete (HPC) was investigated in the article. Temperature distribution in HPC elements around integrated CMT...

  12. Vibration and bending analyses of magneto-electro-thermo-elastic sandwich microplates resting on viscoelastic foundation

    Science.gov (United States)

    Arefi, Mohammad; Zenkour, Ashraf M.

    2017-08-01

    Magneto-electro-thermo-mechanical bending and free vibration analysis of a sandwich microplate using strain gradient theory is expressed in this paper. The sandwich plate is made of a core and two integrated piezo-magnetic face sheets. The structure is subjected to electric and magnetic potentials, thermal loadings, and resting on Pasternak's foundation. Electro-magnetic equations are developed by considering the variation form of Hamilton's principle. The effects of important parameters of this problem such as applied electric and magnetic potentials, direct and shear parameter of foundation, three microlength-scale parameters, and two parameters of temperature rising are investigated on the vibration and bending results of problem.

  13. A J Integral Approach for Measuring Cohesive Laws Using a Modified DCB Sandwich Specimen

    DEFF Research Database (Denmark)

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

    2007-01-01

    mode mixities. The sandwich specimen consists of glass fiber faces and Divinycell H200 foam core. Arbitrary stiffening of the sandwich specimen with steel bars adhered to the faces reduces rotations and ensures that the method is useable for a wide range of materials. The J integral is employed...... and the opening of the pre-crack tip is recorded by a commercial digital photogrammetry measurement system. Cohesive laws are extracted by differentiating J with respect to the normal and tangential opening of the pre-crack tip. Some results are presented and discussed....

  14. Application of golay complementary coded excitation schemes for non-destructive testing of sandwich structures

    Science.gov (United States)

    Arora, Vanita; Mulaveesala, Ravibabu

    2017-06-01

    In recent years, InfraRed Thermography (IRT) has become a widely accepted non-destructive testing technique to evaluate the structural integrity of composite sandwich structures due to its full-field, remote, fast and in-service inspection capabilities. This paper presents a novel infrared thermographic approach named as Golay complementary coded thermal wave imaging is presented to detect disbonds in a sandwich structure having face sheets from Glass/Carbon Fibre Reinforced (GFR/CFR) laminates and core of the wooden block.

  15. Face/core debond fatigue crack growth characterization using the sandwich mixed mode bending specimen

    DEFF Research Database (Denmark)

    Manca, Marcello; Quispitupa, Amilcar; Berggreen, Christian

    2012-01-01

    Face/core fatigue crack growth in foam-cored sandwich composites is examined using the mixed mode bending (MMB) test method. The mixed mode loading at the debond crack tip is controlled by changing the load application point in the MMB test fixture. Sandwich specimens were manufactured using H45...... and H100 PVC foam cores and E-glass/polyester face sheets. All specimens were pre-cracked in order to define a sharp crack front. The static debond fracture toughness for each material configuration was measured at different mode-mixity phase angles. Fatigue tests were performed at 80% of the static...

  16. FaceSheet Push-off Tests to Determine Composite Sandwich Toughness at Cryogenic Temperatures

    Science.gov (United States)

    Gates, Thomas S.; Herring, Helen M.

    2001-01-01

    A new novel test method, associated analysis, and experimental procedures are developed to investigate the toughness of the facesheet-to-core interface of a sandwich material at cryogenic temperatures. The test method is designed to simulate the failure mode associated with facesheet debonding from high levels of gas pressure in the sandwich core. The effects of specimen orientation are considered, and the results of toughness measurements are presented. Comparisons are made between room and liquid nitrogen (-196 C) test temperatures. It was determined that the test method is insensitive to specimen facesheet orientation and strain energy release rate increases with a decrease in the test temperature.

  17. Analytical and Numerical Study of Foam-Filled Corrugated Core Sandwich Panels under Low Velocity Impact

    Directory of Open Access Journals (Sweden)

    Mohammad Nouri Damghani

    2016-05-01

    Full Text Available Analytical and finite element simulations are used to predict the effect of core density on the energy absorption of composite sandwich panels under low-velocity impact. The composite sandwich panel contains two facesheets and a foam-filled corrugated core. Analytical model is defined as a two degree-of-freedom system based on equivalent mass, spring, and dashpot to predict the local and global deformation response of a simply supported panel. The results signify a good agreement between analytical and numerical predictions.

  18. Failure analysis of bolted joints in foam-core sandwich composites

    DEFF Research Database (Denmark)

    Zabihpoor, M.; Moslemian, Ramin; Afshin, M.

    2008-01-01

    This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed. These s......This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed...

  19. Assessment of the FasciMol-ELISA in the detection of the trematode Fasciola hepatica in field-collected Galba cubensis: a novel tool for the malacological survey of fasciolosis transmission.

    Science.gov (United States)

    Alba, Annia; Vázquez, Antonio A; Sánchez, Jorge; Fraga, Jorge; Hernández, Hilda; Martínez, Elizabeth; Marcet, Ricardo; Figueredo, Mabel; Sarracent, Jorge

    2016-01-16

    Fasciolosis is one of the food-borne neglected trematodioses that has reemerged as a human disease while its effects on domestic animal health remains of significant economic consideration. Being snail-borne disease, the accurate and time-saving epidemiological surveillance of the transmission foci where infected lymnaeid snails occur could be essential to effectively focus or redirect control strategies. For this purpose, the first monoclonal antibody-based immunoenzymatic assay to detect Fasciola hepatica-infected snails (FasciMol-ELISA) was recently developed and showed a high sensitivity and specificity when tested in an experimental F. hepatica - Galba cubensis system. Here, we surveyed populations of G. cubensis occurring in western Cuba for the assessment of the FasciMol-ELISA in determining natural F. hepatica infection in this intermediate host. A multiplex PCR, previously developed to detect F. hepatica in G. cubensis, was used for sample classification. Snail dissection method was also employed as screening technique. A Χ(2) test and a Kappa index were calculated to evaluate the positivity and the level of agreement between the FasciMol-ELISA and the snail dissection methods with the multiplex PCR, respectively. Galba cubensis was found in nine out of 12 sampled localities of which four were positive for F. hepatica infection as detected by both immunoenzymatic and PCR-based assays. The overall prevalence was higher than the natural infection rates previously reported for Cuban G. cubensis (range from 4.1 to 7.42% depending on the screening method). No significant differences were found between FasciMol-ELISA and multiplex PCR when determining parasite positivity (Χ(2) = 6.283; P = 0.0981) whereas an excellent agreement was also noted (Kappa = 0.8224). Our results demonstrate the importance of malacological surveys in assessing parasite transmission risk and constitute an alert on the need of accurate measures to control fasciolosis in

  20. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte

  1. Experimental investigation of interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device

    DEFF Research Database (Denmark)

    Martakos, G.; Andreasen, J.H.; Berggreen, Christian

    2017-01-01

    A recently proposed face-sheet–core interface crack arresting device is implemented in sandwich beams and tested using the Sandwich Tear Test configuration. Fatigue loading conditions are applied to propagate the crack and determine the effect of the crack stopper on the fatigue growth rate and a...

  2. Analysis of Grid-Scored Sandwich Structures of Different Curvatures and Grid Sizes For Wind Turbine Blades

    DEFF Research Database (Denmark)

    Laustsen, Steffen; Thomsen, Ole Thybo; Lund, Erik

    2012-01-01

    The stress and strain field developed locally in-situ the core of grid-scored sandwich structures in wind turbine blades is investigated. Due to the many singularities occurring from the “tri-material corners”, a full 3D analysis of the sandwich structure in terms of the Finite Element Method is ...

  3. Quantum mechanical design and structures of hexanuclear sandwich complex and its multidecker sandwich clusters (Li6)n([18]annulene)n+1 (n = 1-3).

    Science.gov (United States)

    Wang, Shu-Jian; Li, Ying; Wu, Di; Wang, Yin-Feng; Li, Zhi-Ru

    2012-09-13

    By means of density functional theory, a hexanuclear sandwich complex [18]annulene-Li6-[18]annulene which consists of a central Li6 hexagon ring and large face-capping ligands, [18]annulene, is designed and investigated. The large interaction energy and HOMO-LUMO gap suggest that this novel charge-separated complex is highly stable and may be experimentally synthesized. In addition, the stability found in the [18]annulene-Li6-[18]annulene complex extends to multidecker sandwich clusters (Li6)n([18]annulene)n+1 (n = 2-3). The energy gain upon addition of a [18]annulene-Li6 unit to (Li6)n-1([18]annulene)n is pretty large (96.97-98.22 kcal/mol), indicating that even larger multideckers will also be very stable. Similar to ferrocene, such a hexanuclear sandwich complex could be considered as a versatile building block to find potential applications in different areas of chemistry, such as nanoscience and material science.

  4. Sandwich immunoassay for alpha-fetoprotein in human sera using gold nanoparticle and magnetic bead labels along with resonance Rayleigh scattering readout

    International Nuclear Information System (INIS)

    Lu, Yao; Huang, Xiangyi; Ren, Jicun

    2013-01-01

    We describe a sensitive sandwich immunoassay for alpha-fetoprotein (AFP). It is making use of gold nanoparticles (GNPs) and magnetic beads (MBs) as labels, and of resonance Rayleigh scattering for detection. Two antibodies were labeled with GNPs and MBs, respectively, and MB-antigen-GNP complexes were formed in the presence of antigens. The MB labels also serve as solid phase carriers that can be used to magnetically separate the immuno complex. The GNP labels are used as optical probes, and Rayleigh scattering was used to determine the concentration of free GNPs-antibody after separation of the MB-antigen-GNP complexes. The concentration of AFP is related to the intensity of light scattered by free GNPs in the 13.6 pM to 436 pM concentration range, and the limit of detection is 13.6 pM. The method was applied to the determination of AFP in sera of cancer patients, and the results agree well with those obtained by conventional ELISA. (author)

  5. Thermo-mechanical interaction effects in foam cored sandwich panels-correlation between High-order models and Finite element analysis results

    DEFF Research Database (Denmark)

    Palleti, Hara Naga Krishna Teja; Santiuste, Carlos; Thomsen, Ole Thybo

    2010-01-01

    Thermo-mechanical interaction effects including thermal material degradation in polymer foam cored sandwich structures is investigated using the commercial Finite Element Analysis (FEA) package ABAQUS/Standard. Sandwich panels with different boundary conditions in the form of simply supported...

  6. Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

    Science.gov (United States)

    Azmi, M. A.; Abdullah, H. Z.; Idris, M. I.

    2013-12-01

    This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction.

  7. Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

    International Nuclear Information System (INIS)

    Azmi, M A; Abdullah, H Z; Idris, M I

    2013-01-01

    This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction

  8. A Simple and Specific Noncompetitive ELISA Method for HT-2 Toxin Detection

    Directory of Open Access Journals (Sweden)

    Henri O. Arola

    2017-04-01

    Full Text Available We developed an HT-2 toxin-specific simple ELISA format with a positive read-out. The assay is based on an anti-immune complex (IC scFv antibody fragment, which is genetically fused with alkaline phosphatase (AP. The anti-IC antibody specifically recognizes the IC between a primary anti-HT-2 toxin Fab fragment and an HT-2 toxin molecule. In the IC ELISA format, the sample is added together with the scFv-AP antibody to the ELISA plate coated with the primary antibody. After 15 min of incubation and a washing step, the ELISA response is read. A competitive ELISA including only the primary antibody recognizes both HT-2 and T-2 toxins. The anti-IC antibody makes the assay specific for HT-2 toxin, and the IC ELISA is over 10 times more sensitive compared to the competitive assay. Three different naturally contaminated matrices: wheat, barley and oats, were used to evaluate the assay performance with real samples. The corresponding limits of detection were 0.3 ng/mL (13 µg/kg, 0.1 ng/mL (4 µg/kg and 0.3 ng/mL (16 µg/kg, respectively. The IC ELISA can be used for screening HT-2 toxin specifically and in relevant concentration ranges from all three tested grain matrices.

  9. Detection of Fusarium verticillioides by PCR-ELISA based on FUM21 gene.

    Science.gov (United States)

    Omori, Aline Myuki; Ono, Elisabete Yurie Sataque; Bordini, Jaqueline Gozzi; Hirozawa, Melissa Tiemi; Fungaro, Maria Helena Pelegrinelli; Ono, Mario Augusto

    2018-08-01

    Fusarium verticillioides is a primary corn pathogen and fumonisin producer which is associated with toxic effects in humans and animals. The traditional methods for detection of fungal contamination based on morphological characteristics are time-consuming and show low sensitivity and specificity. Therefore, the objective of this study was to develop a PCR-ELISA based on the FUM21 gene for F. verticillioides detection. The DNA of the F. verticillioides, Fusarium sp., Aspergillus sp. and Penicillium sp. isolates was analyzed by conventional PCR and PCR-ELISA to determine the specificity. The PCR-ELISA was specific to F. verticillioides isolates, showed a 2.5 pg detection limit and was 100-fold more sensitive than conventional PCR. In corn samples inoculated with F. verticillioides conidia, the detection limit of the PCR-ELISA was 1 × 10 4 conidia/g and was also 100-fold more sensitive than conventional PCR. Naturally contaminated corn samples were analyzed by PCR-ELISA based on the FUM21 gene and PCR-ELISA absorbance values correlated positively (p PCR-ELISA developed in this study can be useful for F. verticillioides detection in corn samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Homologous ELISA for detection of oligomeric human TNF: properties of the assay.

    Science.gov (United States)

    Petyovka, N; Lyach, L; Voitenok, N N

    1995-10-26

    In order to quantify oligomeric human tumor necrosis factor-alpha (TNF), we have developed a sensitive homologous enzyme-linked immunosorbent assay (Hm-ELISA) using the same monoclonal antibody (MoAb) for both solid and liquid phase. Different anti-TNF MoAb have been compared in terms of their efficacy in the Hm-ELISA, affinity, neutralization capacity and epitope specificity. The data suggest, that effectiveness in the Hm-ELISA may represent a novel characteristic of MoAb. Of the MoAbs tested, 5 N was capable of recognizing oligomeric TNF in the Hm-ELISA with a detection limit of 15 pg/ml. Furthermore, using Hm-ELISA against human TNF, interleukin-8 (IL-8) and lymphotoxin, we have demonstrated that these cytokines are oligomeric in physiological solutions, but are converted into monomeric forms in the presence of the non-ionic detergent Tween 20. High salt buffer was employed to abrogate a nonspecific false positive reaction in the Hm-ELISA found in nearly half of the plasma samples obtained from healthy subjects. Finally, a good correlation between the Hm-ELISA and the L929 bioassay was observed for natural and recombinant TNF measured in human plasma.

  11. Evaluation of serum and milk ELISAs for paratuberculosis in Danish dairy cattle

    DEFF Research Database (Denmark)

    Klausen, Joan; Huda, A.; Ekeroth, Lars

    2003-01-01

    concurrently from six dairy herds infected with MAP and from two dairy herds without history of infection with MAP. A cut-off value of 7 OD% was used in the ELISAs. At this cut-off value, all six culture-positive herds were positive in the serum ELISA but one was negative in the milk ELISA. All six culture......-positive herds were positive in the CFT. In the two culture-negative herds, the serum and the milk ELISA deemed all serum samples negative at this cut-off value, whereas four serum samples from one of these herds were positive in the CFT. The highest cut-off value enabling the milk ELISA to record all six...... culture-positive herds as positive was 4 OD%. The highest cut-off value enabling the serum ELISA to record all six culture-positive herds as positive was 17 OD%. Individual-sample relative sensitivities of the ELISAs ranged from 49 to 64% and relative specificities were 80-96% at the cut-off values of 4...

  12. [Use of new immunoglobulin isotype-specific ELISA-systems to detect Salmonella infections in pigs].

    Science.gov (United States)

    Ehlers, Joachim; Alt, Michael; Trepnau, Daniela; Lehmann, Jörg

    2006-01-01

    In Germany, the program for controlling salmonella infections in pigs is based on tests detecting salmonella-lipopolysaccharide (LPS) induced antibodies in meat-juice or blood. These conventional tests which are based on the technology of enzyme-linked immunosorbent assay (ELISA) detect exclusively or mainly immunoglobulin(lg)G antibodies. Meanwhile, novel ELISA systems (WCE-ELISA, 3-Isotype-Screening-ELISA) have been developed, which additionally detect the antibody classes IgM and IgA.This fact enables the registration of fresh salmonella infections (starting with day 5 p.i.) and thus, the distinction between early and older infections. The results show that animals with early salmonella infections appear significantly more often in herds with a high than with a low prevalence. With the newly developed tests this group of animals can be detected much more efficiently and precisely than with the tests used so far. Due to their clearly improved sensitivity the application of the WCE-ELISA and the 3-Isotype-Screening-ELISA in terms of the QS-Salmonella-Monitoring program can therefore significantly improve the selection of farms with potential salmonella excretors. Additionally, the WCE-ELISA can be applied very suitable for the examination of individual animals.

  13. Microchip ELISA coupled with cell phone to detect ovarian cancer HE4 biomarker in urine.

    Science.gov (United States)

    Wang, ShuQi; Akbas, Ragip; Demirci, Utkan

    2015-01-01

    Ovarian cancer is a leading cause of death from gynecologic cancers in the USA, and early diagnosis can potentially increase 5-year survival rate. Detection of biomarkers derived from hyperplasia of epithelial tissue by enzyme-linked immunosorbent assay (ELISA) proves to be a practical way of early diagnosis of ovarian cancer. However, ELISA is commonly performed in a laboratory setting, and it cannot be used in a clinical setting for on-site consultation. We have shown a microchip ELISA that detects HE4, an ovarian cancer biomarker, from urine using a cell phone integrated with a mobile application for imaging and data analysis. In microchip ELISA, HE4 from urine was first absorbed on the surface; the primary and secondary antibodies were subsequently anchored on the surface via immuno-reaction; and addition of substrate led to color development because of enzymatic labeling. The microchip after color development was imaged using a cell phone, and the color intensity was analyzed by an integrated mobile application. By comparing with an ELISA standard curve, the concentration of HE4 was reported on the cell phone screen. The presented microchip ELISA coupled with a cell phone is portable as opposed to traditional ELISA, and this method can facilitate the detection of ovarian cancer at the point-of-care (POC).

  14. EVALUATION OF AN O-ANTIGEN ELISA FOR SCREENING CATTLE HERDS FOR SALMONELLA-TYPHIMURIUM

    DEFF Research Database (Denmark)

    Hoorfar, Jeffrey; Bitsch, V.

    1995-01-01

    A total of 2585 serum samples from 62 dairy herds located in four different regions of Denmark were tested in an O-antigen (0:1,4,5,12)-based ELISA for the detection of antibodies against Salmonella typhimurium. Ten closed herds from an island with no reported occurrence of salmonellosis for seve......A total of 2585 serum samples from 62 dairy herds located in four different regions of Denmark were tested in an O-antigen (0:1,4,5,12)-based ELISA for the detection of antibodies against Salmonella typhimurium. Ten closed herds from an island with no reported occurrence of salmonellosis...... for several years, and 12 herds from a salmonella enzootic area which had had clinical outbreaks of S typhimurium were used to define a herd ELISA cut-off value. When herds with at least 5 per cent of the serum samples having an optical density of >0.5 were considered ELISA-positive, all 10 herds from...... the salmonellosis-free island were ELISA-negative, and all but one of the 12 S typhimurium-infected herds were ELISA-positive, which resulted in a herd test sensitivity of 0.92 and herd test specificity of 1.0. Eleven of the 12 S typhimurium-infected herds were negative in a blocking ELISA based on a monoclonal...

  15. RT-PCR-ELISA as a tool for diagnosis of low-pathogenicity avian influenza

    DEFF Research Database (Denmark)

    Dybkaer, Karen; Munch, Mette; Handberg, Kurt Jensen

    2003-01-01

    A one-tube reverse transcriptase/polymerase chain reaction coupled with an enzyme-linked immunosorbent assay (RT-PCR-ELISA) was developed for the rapid detection of avian influenza virus (AIV) in clinical specimens. A total of 419 swab pools were analyzed from chickens experimentally infected wit...... of the twenty-three VI-positive specimens were negative when tested by RT-PCR-ELISA. The diagnostic sensitivity and specificity of the RT-PCR-ELISA was 91% and 97%, respectively, using VI in SPF eggs as the gold reference standard....

  16. Use of a trypanosomal antigen ELISA to monitor tsetse and trypanosomosis control programmes in Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Olaho-Mukani, W; Munga, L K; Nyanga` O, J N.M.; Ouma, J O; Masika, P; Okech, G; Ndungu, J M [Kenya Trypanosomiasis Research Inst., Kikuyu (Kenya)

    1997-02-01

    The capture Antigen-ELISA was used to monitor serum samples originating from three study areas in Kenya. At the Galana ranch the test was used to assess re-invasion of an area previously cleared of Glossina pallidipes. In Busia district the Ag-ELISA is being used to monitor the progress of a tsetse and trypanosomosis control programme. At Taita and Tara ranches the capture Antigen ELISA and the buffy coat technique (BCT) were used to evaluate the efficacy of a commercial Cypermethrin dip for the control of Glossina pallidipes. (author). 3 refs, 4 figs, 2 tabs.

  17. Development and evaluation of an ELISA for human trefoil factor 3

    DEFF Research Database (Denmark)

    Vestergaard, Else Marie; Poulsen, Steen Seier; Grønbaek, Henning

    2002-01-01

    are warranted. METHODS: An ELISA was developed that uses two antibodies from rabbits immunized with recombinant human TFF3 and a calibrator (3-100 pmol/L) prepared from recombinant human TFF3. RESULTS: The ELISA had a detection limit of 3.0 pmol/L. The imprecision (CV) was 5-9% for mean concentrations of 13...... exacerbation of chronic inflammatory bowel disease restricted to the colon, normal concentrations and only minor variations during treatment and tapering were observed. CONCLUSIONS: The ELISA measures TFF3 in human serum and represents a specific and precise method for measurement of TFF3, which...

  18. DETECTION OF SERIAL SERUM P-185 LEVEL IN PATIENTS WITH MALIGNANCY USING ELISA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-hui; WU Ping; LI Li; MIAO Yi-meng; LI Jun

    2006-01-01

    Objective: To investigate P-185 contents in serum of the normal person and cancer patients and it's the significance on prognosis of diseases. Methods: We used ELISA method to evaluate P-185 levels in 193 normal persons, 133 malignancies and 34 hepatocirrhosises were evaluated using ELISA method. Results: Normal person had lower expression of P-185. However, malignancy and hepatocirrhosis patients had a significantly higher expression level of P-185 than normal (P<0.05). Conclusion: ELISA method is an easy and reliable way to measure the level of P-185 in serum. Being a cancer marker, P-185 overexpression can be used for early diagnosis and prognosis of cancer patients.

  19. A new type of sandwich panel with periodic cellular metal cores and its mechanical performances

    International Nuclear Information System (INIS)

    Lim, Chae-Hong; Jeon, Insu; Kang, Ki-Ju

    2009-01-01

    Many studies have been performed on the mechanical properties and optimization of truss PCMs (periodic cellular metals), but those on the fabrication process, which is one of key factors determining the survivability of PCMs in the market, have been relatively limited. This study introduces a new idea on the fabrication of quasi Kagome truss cored sandwich panels, which is based on the expanded-metal process. And the mechanical behavior of the sandwich panels is to be evaluated. The mechanical strengths and failure mechanisms under compression and bending load are estimated based on elementary mechanics of materials, and the optimal design is derived. Its validity is proved by comparison with the results of experiments. The results showed that the new idea is promising with respect to all three requirements, i.e., the morphology, fabrication cost, and raw materials. The simple mechanical analysis was sufficiently effective and accurate for estimating the performance and failure mode of the sandwich panels. In the experiments, sandwich panel specimens of three different designs were compared in their bending behaviors to demonstrate sensitivity of geometric parameters. Namely, although all the designs had little difference in their load capacity-per-weight, the failure mechanisms and the behaviors after a peak load were totally different.

  20. Investigation of Sandwich Material Surface Created by Abrasive Water Jet (AWJ) via Vibration Emission

    Czech Academy of Sciences Publication Activity Database

    Hreha, P.; Hloch, S.; Monka, P.; Monková, K.; Knapčíková, L.; Hlaváček, Petr; Zeleňák, Michal; Samardžič, I.; Kozak, D.

    2013-01-01

    Roč. 53, č. 1 (2013), s. 29-32 ISSN 0543-5846 Institutional support: RVO:68145535 Keywords : sandwich material * stainless steel * abrasive water jet cutting Subject RIV: JJ - Other Materials Impact factor: 0.755, year: 2013 http://public.carnet.hr/metalurg/Metalurgija/2014_vol_53/No_1/MET_53_1_29-32_Hreha.pdf

  1. Changing Welfare States and the “Sandwich Generation” : Increasing Burden for the Next Generation?

    Directory of Open Access Journals (Sweden)

    Harald Künemund

    2006-12-01

    Full Text Available The burden placed on individuals aged 40 to 59 – especially on women – by competing demands from work and both older and younger family members is often addressed using the metaphor of the „sandwich gen-eration“. Based on a systematization of the definitions used in the litera-ture, empirical evidence on the frequency of such generational constella-tions and on their impact on the well-being of sandwiched adults will be presented. Analysing the second wave of the German Aging Survey shows that being sandwiched – defined as a generational constellation – is very common, but simultaneous care activities for both older and younger family members are rare, especially in combination with labour force participation, and that life satisfaction is not systematically related to being sandwiched. Implications for further research and future devel-opments will be discussed, especially with respect to changes in family structure (e.g. the beanpole family and changes in the amount of welfare state spending for the aged.

  2. Occurrence of Foodborne Pathogens in Chickens Sandwiches Distributed in Different Supermarkets of Tehran Province, Iran

    Directory of Open Access Journals (Sweden)

    Zohreh Mashak

    2014-07-01

    Full Text Available Background: Increasing urbanization, immigration and tourism has changed the human lifestyle. This modern lifestyle has demanded safety, quality, and fast availability of ready to eat (RTE foods like chicken sandwiches. Objectives: For presentation of proper solutions regarding food safety, identification of pathogens in different foods is necessary. Therefore, the present study was carried out to assess the microbiological quality of chicken sandwiches distributed in Tehran province, Iran. Materials and Methods: A total of 200 chicken sandwich samples (chicken sausage, chicken fillet, minced chicken fillet were purchased from different supermarkets in Tehran city randomly during 2013 and transported to the laboratory of food hygiene of Islamic Azad University, Karaj branch under temperature-controlled conditions for bacteriological examination by American Public Health Association (APHA method. Results: The average count ± standard error (and percent of unacceptable samples of S. aureus, B. cereus and Coliform were 1.6 ± 0.56 (28%, 2.0 ± 0.62 (10%, 4.2 ± 1.12 (50% CFU/g, respectively. Moreover, E. coli and Salmonella spp. were identified in 21% of chicken sandwich samples. Conclusions: The large number of foodborne pathogens detected in this study, represented a potential health hazard to consumers. Thus, it is necessary to employ Good Hygiene Practices (GHP and Hazard Analysis and Critical Control Points (HACCP in order to minimize the risk caused by secondary contamination.

  3. A More Sustainable Way for Producing RC Sandwich Panels On-Site and in Developing Countries

    Directory of Open Access Journals (Sweden)

    Lorenzo Graziani

    2017-03-01

    Full Text Available The purpose of this work is to assess if traditionally used welded connectors for joining the two skins of reinforced concrete (RC sandwich panels, used as structural walls and horizontal structural elements, can be substituted with bent ones. In this way, the scope of the effort is to reduce drastically the energy required during manufacturing, thus having a much more sustainable building product. Wire mesh on site production, in fact, requires a large amount of energy for the welding process, as stated by several Environmental Product Declaration (EPD. In addition, the production of sandwich panels with bent connectors requires a low level of automation and no qualified labor allowing the diffusion in developing countries. The procedures used to execute the work were both experimental and numerical. Structural performances were examined by testing full-scale sandwich panels under (axial and eccentric compression and flexural loads. Additionally, a Finite Element (FE study was developed to investigate and to optimize the dimension of welded mesh and the number of connectors. The major findings show that it is possible to substitute welded connectors with bent ones without compromising the structural performance of the tested RC sandwich panels, thus having a more sustainable way for producing these last ones.

  4. A numerical simulation of metallic cylindrical sandwich shells subjected to air blast loading

    Directory of Open Access Journals (Sweden)

    Lin Jing

    Full Text Available The dynamic response of cylindrical sandwich shells with aluminum foam cores subjected to air blast loading was investigated numerically in this paper. According to KNR theory, the nonlinear compressibility of the air and finite shock conditions were taken into account in the finite element model. Numerical simulation results show that the compression strain, which plays a key role on energy absorption, increases approximately linearly with normalized impulse, and reduces with increasing relative density or the ratio of face-sheet thickness and core thickness. An increase of the impulse will delay the equalization of top and bottom face-sheet velocities of sandwich shell, but there is a maximum value in the studied bound. A limited study of weight optimization was carried out for sandwich shells with respect to the respective geometric parameters, including face-sheet thickness, core thickness and core relative density. These numerical results are of worth to theoretical prediction and engineering application of cellular metal sandwich structures.

  5. 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...

  6. A phloem sandwich allowing attack and colonization by bark beetles (Coleoptera: Scolytidae) and associates

    Science.gov (United States)

    Andrew D. Taylor; Jane L. Hayes; John C. Moser

    1992-01-01

    Much of the life cycles of bark beetles and their associates are spent under the bark of the host tree and are impossible to observe under completely natural conditions. To observe the behavior and development of insects in the phloem layer, phloem sandwiches have been developed, in which a piece of bark and phloem is removed from a live tree and pressed against a...

  7. The Association between Membership in the Sandwich Generation and Health Behaviors: A Longitudinal Study

    Science.gov (United States)

    Chassin, Laurie; Macy, Jon T.; Seo, Dong-Chul; Presson, Clark C.; Sherman, Steven J.

    2010-01-01

    The current study examined the association between membership in the sandwich generation, defined as providing care to both children and parents or in-laws, and five health behaviors: checking the food label for health value when buying foods, using a seat belt, choosing foods based on health value, exercising regularly, and cigarette smoking.…

  8. Highly efficient construction of oriented sandwich structures for surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    Guo Hongyun; Xu Weiqing; Xu Shuping; Zhou Ji; Lombardi, John R

    2013-01-01

    The purpose of this study is to solve the problem of low achievement in fabricating sandwich surface-enhanced Raman scattering (SERS) substrates. We demonstrated a highly efficient sandwich structure by the oriented assembly of metal nanoparticles (NPs) on a periodic hexagonal array of metal nanoprisms with 1,4-benzenedithiol (1,4-BDT) as linkers. The metal nanoprism array was prepared by vacuum deposition of metal on a close-packed polystyrene nanosphere pre-patterned substrate. The metal nanoprism array presents different surface properties from the pits left from the removal of polystyrene nanospheres, which causes linkers to selectively adsorb on the metal nanoprism array and sequentially leads to the oriented immobilization of the second-layer metal NPs, avoiding mismatched orientation. These sandwich SERS substrates were characterized by extinction spectroscopy and atomic force microscopy and their enhancement activity was evaluated under different excitation wavelengths. The sandwich structure greatly increases the achievement of ‘hot spots’ to almost 100% of all the metal nanoprisms and enables a large amplification of SERS signals by a factor of ten. This method has the advantages of simplicity, high efficiency, high throughput, controllability and high reproducibility. It has significance in both the study of SERS substrates and the development of plasmonic devices. (paper)

  9. PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration

    Directory of Open Access Journals (Sweden)

    Xiaoyuan Wei

    2017-09-01

    Full Text Available Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

  10. Effects of debonds and face sheet damage in GRP sandwich panels in naval ships

    DEFF Research Database (Denmark)

    Hayman, B.; Berggreen, Christian; Quispitupa, Amilcar

    2009-01-01

    Sandwich construction with face sheets of fibre-reinforced plastics (FRP) and a core of polymer foam or balsa wood offer a lightweight construction that is well suited to naval and other vessels for high-speed operation or where payload considerations require that the structural weight be minimised...

  11. Design of X-joints in Sandwich Structures for Naval Vessels

    DEFF Research Database (Denmark)

    Hayman, Brian; Berggreen, Christian; Lundsgaard-Larsen, Christian

    2007-01-01

    In many naval ships of fibre composite sandwich construction, an X-joint exists where the end bulkhead of the superstructure is attached to the deck, with an internal bulkhead placed in the same vertical plane below the deck. This joint is subjected to alternating tensile and compressive loading...

  12. Effects of face sheet damage on residual strength of GRP sandwich panels in naval ships

    DEFF Research Database (Denmark)

    Hayman, Brian; Echtermeyer, Andreas T.; Berggreen, Christian

    2010-01-01

    is represented by machined cracks and circular holes in the face laminates. Tests have been performed on laminate specimens with and without circular holes under tensile loading and on sandwich face sheets with holes, cracks and real impact damage under compressive loading. The results are compared...

  13. Buckling tests of sandwich cylindrical shells with and without cut-outs

    NARCIS (Netherlands)

    Bisagni, C.; Davidson, B.D.; Czabaj, M.W.; Ratcliffe, J.G.

    2016-01-01

    The results of buckling tests performed during the project DESICOS funded by the European Commission in the FP7 Programme are here presented. The tested structures are sandwich cylindrical shells that consist of reduced models of a component of the Ariane 5 launcher: the Dual Launch System. In

  14. Fracture Behaviours in Compression-loaded Triangular Corrugated Core Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Zaid N.Z.M.

    2016-01-01

    Full Text Available The failure modes occurring in sandwich panels based on the corrugations of aluminium alloy, carbon fibre-reinforced plastic (CFRP and glass fibre-reinforced plastic (GFRP are analysed in this work. The fracture behaviour of these sandwich panels under compressive stresses is determined through a series of uniform lateral compression performed on samples with different cell wall thicknesses. Compression test on the corrugated-core sandwich panels were conducted using an Instron series 4505 testing machine. The post-failure examinations of the corrugated-core in different cell wall thickness were conducted using optical microscope. Load-displacement graphs of aluminium alloy, GFRP and CFRP specimens were plotted to show progressive damage development with five unit cells. Four modes of failure were described in the results: buckling, hinges, delamination and debonding. Each of these failure modes may dominate under different cell wall thickness or loading condition, and they may act in combination. The results indicate that thicker composites corrugated-core panels tend can recover more stress and retain more stiffness. This analysis provides a valuable insight into the mechanical behaviour of corrugated-core sandwich panels for use in lightweight engineering applications.

  15. A three-dimensional carbon nanotube/graphene sandwich and its application as electrode in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhuangjun; Yan, Jun; Wei, Tong; Feng, Jing; Zhang, Milin [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin (China); Zhi, Linjie [National Center for Nanoscience and Technology of China, Beijing (China); Zhang, Qiang; Qian, Weizhong; Wei, Fei [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing (China)

    2010-09-01

    Three-dimensional carbon nanotube/graphene sandwich structures with CNT pillars grown in between the graphene layers have been developed by chemical vapor deposition. The special structure endows the high-rate transportation of electrolyte ions and electrons throughout the electrode matrix, resulting in excellent electrochemical performance of this hybrid material. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  16. Structural differences of half-sandwich complexes of scandium and yttrium containing bulky substituents

    Czech Academy of Sciences Publication Activity Database

    Fridrichová, Adéla; Růžička, A.; Lamač, Martin; Horáček, Michal

    2017-01-01

    Roč. 76, FEB 2017 (2017), s. 62-66 ISSN 1387-7003 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : scandium * yttrium * half-sandwich Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.640, year: 2016

  17. Probabilistic fatigue life of balsa cored sandwich composites subjected to transverse shear

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov; Berggreen, Christian

    2015-01-01

    A probabilistic fatigue life model for end-grain balsa cored sandwich composites subjectedto transverse shear is proposed. The model is calibrated to measured three-pointbending constant-amplitude fatigue test data using the maximum likelihood method. Some possible applications of the probabilistic...

  18. Cone calorimeter testing of foam core sandwich panels treated with intumescent paper underneath the veneer (FRV)

    Science.gov (United States)

    Mark A. Dietenberger; Ali Shalbafan; Johannes Welling

    2017-01-01

    Surfaces of novel foam core sandwich panels were adhered with intumescent fire‐retardant paper underneath the veneers (FRV) to improve their flammability properties. The panels were evaluated by means of cone calorimeter test (ASTM E 1354). Variables tested were different surface layer treatments, adhesives used for veneering, surface layer thicknesses, and processing...

  19. Fatigue Failure of Sandwich Beams with Wrinkle Defects Used for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Leong, Martin Klitgaard; Hvejsel, C.F.; Lund, Erik

    2012-01-01

    Glass fiber face sheet/balsa wood core sandwich beams with out-of-plane fiber misalignments/wrinkle defects were subjected to in-plane fully reversed fatigue loading and the failure modes were documented. A fatigue life design limit was estimated using finite element analyses and the Northwestern...

  20. Modified sandwich vacuum pack technique for temporary closure of abdominal wounds: an African perspective.

    Science.gov (United States)

    van As, A B; Navsaria, P; Numanoglu, A; McCulloch, M

    2007-01-01

    South Africa has very high levels of accidental trauma as well as interpersonal violence. There are more admissions for trauma in South Africa than for any other disease; therefore it can be regarded as the Number 1 disease in the country. Complex abdominal injuries are common, requiring specific management techniques. The aim is to document our experience with the Modified Sandwich Vacuum Pack technique for temporary closure of abdominal wounds. After providing a short historical overview, we will demonstrate the technique which we carefully adapted over the last decade to the present Modified Sandwich Vacuum Pack technique. In the Last 5 years we utilized our Modified Sandwich Vacuum Pack technique 153 times in 69 patients. Five (5) patients were under the age of 12 years. In the patient group over 12 years the most common indication for using our technique were penetrating injuries (40), abdominal sepsis (28), visceral edema (10), abdominal compartment syndrome (9), abdominal packs (6),Abdominal wall defects (2). In the group under 12-years the 2 children had liver ruptures (posttraumatic) and 3 liver transplantations. The average cost for the materials used with our technique was ZAR 96. (10 Euro and 41 cents). In our experience the Modified Sandwich Vacuum Pack technique is an effective, cheap methodology to deal with open abdomens in the African setting.A drawback may be the technical expertise required, particular in centers dealing with low numbers of complex abdominal trauma.

  1. Application and Analysis of Sandwich Elements in the Primary Structure of Large Wind Turbine Blades

    DEFF Research Database (Denmark)

    Berggreen, Christian; Branner, Kim; Jensen, Jacob Fisker

    2007-01-01

    The present work studies the advantages of applying a sandwich construction as opposed to traditional single skin composites in the flanges of a load carrying spar in a future 180 m wind turbine rotor. A parametric finite element model is used to analyze two basic designs with single skin...

  2. PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration.

    Science.gov (United States)

    Wei, Xiaoyuan; Yang, Yuan; Yao, Wenqing; Zhang, Lei

    2017-09-30

    Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

  3. Modal analysis and acoustic transmission through offset-core honeycomb sandwich panels

    Science.gov (United States)

    Mathias, Adam Dustin

    The work presented in this thesis is motivated by an earlier research that showed that double, offset-core honeycomb sandwich panels increased thermal resistance and, hence, decreased heat transfer through the panels. This result lead to the hypothesis that these panels could be used for acoustic insulation. Using commercial finite element modeling software, COMSOL Multiphysics, the acoustical properties, specifically the transmission loss across a variety of offset-core honeycomb sandwich panels, is studied for the case of a plane acoustic wave impacting the panel at normal incidence. The transmission loss results are compared with those of single-core honeycomb panels with the same cell sizes. The fundamental frequencies of the panels are also computed in an attempt to better understand the vibrational modes of these particular sandwich-structured panels. To ensure that the finite element analysis software is adequate for the task at hand, two relevant benchmark problems are solved and compared with theory. Results from these benchmark results compared well to those obtained from theory. Transmission loss results from the offset-core honeycomb sandwich panels show increased transmission loss, especially for large cell honeycombs when compared to single-core honeycomb panels.

  4. The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2016-01-01

    Full Text Available Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

  5. Improving Performance of Polymer Fiber Reinforced Sandwich X-Joints in Naval Vessels

    DEFF Research Database (Denmark)

    Berggreen, Christian; Lundsgaard-Larsen, Christian; Karlsen, Kasper

    2007-01-01

    In many naval ships of fiber composite sandwich construction an X-joint exists where the end bulkhead of the superstructure is attached to the deck, with a bulkhead placed in the same vertical plane below the deck. As the hull girder flexes this joint is subjected to alternating tensile and compr...

  6. Buckling and Fracture Investigation of Debonded Sandwich Columns: An Experimental and Numerical Study

    DEFF Research Database (Denmark)

    Berggreen, Christian; Carlsson, Leif A.; Avilés, F.

    2008-01-01

    An experimental and numerical study of in-plane compression of foam core sandwich columns with implanted trough width face/core debond is presented. Experiments were conducted for columns with two different face thicknesses over different cores and debond lengths. The debonded region was monitore...

  7. A novel sandwich Fe-Mn damping alloy with ferrite shell prepared by vacuum annealing

    Science.gov (United States)

    Qian, Bingnan; Peng, Huabei; Wen, Yuhua

    2018-04-01

    To improve the corrosion resistance of high strength Fe-Mn damping alloys, we fabricated a novel sandwich Fe-17.5Mn damping alloy with Mn-depleted ferrite shell by vacuum annealing at 1100 °C. The formation behavior of the ferrite shell obeys the parabolic law for the vacuum annealed Fe-17.5Mn alloy at 1100 °C. The sandwich Fe-17.5Mn alloy with ferrite shell exhibits not only better corrosion resistance but also higher damping capacity than the conventional annealed Fe-17.5Mn alloy under argon atmosphere. The existence of only ferrite shell on the surface accounts for the better corrosion in the sandwich Fe-17.5Mn alloy. The better damping capacity in the sandwich Fe-17.5Mn alloy is owed to more stacking faults inside both ɛ martensite and γ austenite induced by the stress from ferrite shell. Vacuum annealing is a new way to improve the corrosion resistance and damping capacity of Fe-Mn damping alloys.

  8. Electrochemical DNA sandwich assay with a lipase label for attomole detection of DNA

    DEFF Research Database (Denmark)

    Ferapontova, Elena; Hansen, Majken Nørgaard; Saunders, Aaron Marc

    2010-01-01

    A fast and sensitive electrochemical lipase-based sandwich hybridization assay for detection of attomole levels of DNA has been developed. A combination of magnetic beads, used for pre-concentration and bioseparation of the analyte with a lipase catalyst label allowed detection of DNA with a limi...

  9. 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.

  10. Development and evaluation of aerogel-filled BMI sandwich panels for thermal barrier applications

    Directory of Open Access Journals (Sweden)

    A. Dineshkumar

    2016-07-01

    Full Text Available This study details a fabrication methodology envisaged to manufacture Glass/BMI honeycomb core aerogel-filled sandwich panels. Silica aerogel granules are used as core fillers to provide thermal insulation properties with little weight increase. Experimental heat transfer studies are conducted on these panels to study the temperature distribution between their two surfaces. Numerical studies are also carried out to validate the results. Despite exhibiting good thermal shielding capabilities, the Glass/BMI sandwich panels are found to oxidise at 180 ºC if exposed directly to heat. In order to increase the temperature bearing capacity and the operating temperature range for these panels, a way of coating them from outside with high temperature spray paint was tried. With a silicone-based coating, the temperature sustainability of these sandwich panels is found to increase to 350 ºC. This proved the effectiveness of the formed manufacturing process, selected high temperature coating, the coating method as well as the envisaged sandwich panel concept.

  11. Nanosecond optical limiting response of sandwich-type neodymium dyphthalocyanine in a co-polymer host

    NARCIS (Netherlands)

    Aneeshkumar, B.N.; Gopinath, P.; Thomas, J.; Vallabhan, C.P.G.; Nampoori, V.P.N.; Radhakrishnan, P.

    2004-01-01

    The nanosecond optical limiting characteristics of sandwich-type neodymium diphthalocyanine in a co-polymer matrix of polymethyl methacrylate (PMMA) and methyl-2-cyanoacrylate have been studied for the first time. The measurements were performed using 9 ns laser pulses generated from a

  12. Vibration Characteristics of Axially Moving Titanium- Polymer Nanocomposite Faced Sandwich Plate Under Initial Tension

    Directory of Open Access Journals (Sweden)

    Ali Ghorbanpour Arani

    2017-07-01

    Full Text Available In the present research, vibration and instability of axially moving sandwich plate made of soft core and composite face sheets under initial tension is investigated. Single-walled carbon nano-tubes (SWCNTs are selected as a reinforcement of composite face sheets inside Poly methyl methacrylate (PMMA matrix. Higher order shear deformation theory (HSDT is utilized due to its accuracy of polynomial functions than other plate theories. Based on extended rule of mixture, the structural properties of composite face sheets are taken into consideration. Motion equations are obtained by means of Hamilton’s principle and solved analytically. Influences of various parameters such as axially moving speed, volume fraction of CNTs, pre-tension, thickness and aspect ratio of sandwich plate on the vibration characteristics of moving system are discussed in details. The results indicated that the critical speed of moving sandwich plate is strongly dependent on the volume fraction of CNTs. Therefore, the critical speed of moving sandwich plate can be improved by adding appropriate values of CNTs. The results of this investigation can be used in design and manufacturing of marine vessels and aircrafts.

  13. Bioinspired metal-cell wall-metal sandwich structure on an individual bacterial cell scaffold.

    Science.gov (United States)

    Zhang, Xiaoliang; Yu, Mei; Liu, Jianhua; Li, Songmei

    2012-08-25

    Pd nanoparticles were introduced to individual Bacillus cells and dispersedly anchored on both the inside and outside of the cell walls. The anchored nanoparticles served as "seeds" to drive the formation of double metallic layers forming a metal-cell wall-metal sandwich structure at the single-cell level.

  14. Prevalence of entamoeba histolytica and entamoeba dispar by means of microscopy and ELISA in a suburb of Lima

    International Nuclear Information System (INIS)

    Cornejo, W.; Alva, P.; Suarez, R.; Espinoza, Y.; Huiza, A.; Sevilla, C.; Naquira, C.

    1999-01-01

    To assess the prevalence of E. histolytica and E. dispar in a marginal population of Callao, Lima, using ELISAs. Two ELISAs were used, one of them for both Entamoeba species (Entamoeba-ELISA), and an E. histolytica-specific ELISA. 128 stool samples from randomized Callao inhabitants were microscopically examined. Thirteen (10%) were microscopically diagnosed as having E. histolytica or E. dispar infection; and 7 (6%) were positive to Entamoeba-ELISA (sensitivity= 54%). Five of the 115 samples without cysts of E. histolytica or E. dispar were Entamoeba ELISA positive (specificity= 96%). All samples were negative to the E. histolytica-specific ELISA. The correlation between the microscopical identification and Entamoeba-ELISA was not good, it may be due to an overvaluation of the of the morphological diagnosis. (authors)

  15. Performance of the multitarget Mikrogen Chlamydia trachomatis IgG ELISA in the prediction of tubal factor infertility (TFI) in subfertile women : Comparison with the Medac MOMP IgG ELISA plus

    NARCIS (Netherlands)

    van Ess, Eleanne F.; Ouburg, Sander; Spaargaren, Joke; Land, Jolande A.; Morre, Servaas A.

    2017-01-01

    There is a need for more accurate Chlamydia trachomatis (CT) IgG antibody tests for tubal factor infertility (TFI) diagnostics. We evaluated the predictive value for TFI of Medac ELISA plus (MOMP) and multitarget Mikrogen ELISA (MOMP-CPAF-TARP). Based on Medac ELISA plus results, 183 subfertile

  16. Bayesian estimation of sensitivity and specificity of Coxiella burnetii antibody ELISA tests in bovine blood and milk

    DEFF Research Database (Denmark)

    Paul, Suman; Toft, Nils; Agerholm, Jørgen S.

    2013-01-01

    Serological tests for Coxiella burnetii (the causative agent of Q fever) antibodies are usually based on enzyme linked immunosorbent assay (ELISA) although this method is not thoroughly evaluated. The objective of this study was to determine the sensitivity and specificity of an ELISA for detection...... lactating cows is relatively easy, non-invasive and inexpensive and hence milk ELISA may be a better option for screening lactating cows. But, blood ELISA is an option for screening non-lactating cattle....

  17. Sequential versus "sandwich" sequencing of adjuvant chemoradiation for the treatment of stage III uterine endometrioid adenocarcinoma.

    Science.gov (United States)

    Lu, Sharon M; Chang-Halpenny, Christine; Hwang-Graziano, Julie

    2015-04-01

    To compare the efficacy and tolerance of adjuvant chemotherapy and radiotherapy delivered in sequential (chemotherapy followed by radiation) versus "sandwich" fashion (chemotherapy, interval radiation, and remaining chemotherapy) after surgery in patients with FIGO stage III uterine endometrioid adenocarcinoma. From 2004 to 2011, we identified 51 patients treated at our institution fitting the above criteria. All patients received surgical staging followed by adjuvant chemoradiation (external-beam radiation therapy (EBRT) with or without high-dose rate (HDR) vaginal brachytherapy (VB)). Of these, 73% and 27% of patients received their adjuvant therapy in sequential and sandwich fashion, respectively. There were no significant differences in clinical or pathologic factors between patients treated with either regimen. Thirty-nine (76%) patients had stage IIIC disease. The majority of patients received 6 cycles of paclitaxel with carboplatin or cisplatin. Median EBRT dose was 45 Gy and 54% of patients received HDR VB boost (median dose 21 Gy). There were no significant differences in the estimated 5-year overall survival, local progression-free survival, and distant metastasis-free survival between the sequential and sandwich groups: 87% vs. 77% (p=0.37), 89% vs. 100% (p=0.21), and 78% vs. 85% (p=0.79), respectively. No grade 3-4 genitourinary or gastrointestinal toxicities were reported in either group. There was a trend towards higher incidence of grade 3-4 hematologic toxicity in the sandwich group. Adjuvant chemoradiation for FIGO stage III endometrioid uterine cancer given in either sequential or sandwich fashion appears to offer equally excellent early clinical outcomes and acceptably low toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. The degree of π electron delocalization and the formation of 3D-extensible sandwich structures.

    Science.gov (United States)

    Wang, Xiang; Wang, Qiang; Yuan, Caixia; Zhao, Xue-Feng; Li, Jia-Jia; Li, Debao; Wu, Yan-Bo; Wang, Xiaotai

    2016-04-28

    DFT B3LYP/6-31G(d) calculations were performed to examine the feasibility of graphene-like C42H18 and starbenzene C6(BeH)6 (SBz) polymers as ligands of 3D-extensible sandwich compounds (3D-ESCs) with uninterrupted sandwich arrays. The results revealed that sandwich compounds with three or more C42H18 ligands were not feasible. The possible reason may be the localization of π electrons on certain C6 hexagons due to π-metal interactions, which makes the whole ligand lose its electronic structure basis (higher degree of π electron delocalization) to maintain the planar structure. For comparison, with the aid of benzene (Bz) molecules, the SBz polymers can be feasible ligands for designing 3D-ESCs because the C-Be interactions in individual SBz are largely ionic, which will deter the π electrons on one C6 ring from connecting to those on neighbouring C6 rings. This means that high degree of π electron delocalization is not necessary for maintaining the planarity of SBz polymers. Such a locally delocalized π electron structure is desirable for the ligands of 3D-ESCs. Remarkably, the formation of a sandwich compound with SBz is thermodynamically more favourable than that found for bis(Bz)chromium. The assembly of 3D-ESCs is largely exothermic, which will facilitate future experimental synthesis. The different variation trends on the HOMO-LUMO gaps in different directions (relative to the sandwich axes) suggest that they can be developed to form directional conductors or semiconductors, which may be useful in the production of electronic devices.

  19. The time course of the specific antibody response by various ELISAs in pigs experimentally infected with Toxoplasma gondii

    DEFF Research Database (Denmark)

    Lind, Peter; Haugegaard, J.; Wingstrand, Anne

    1997-01-01

    With the aim of developing routine serological tests for monitoring the Toxoplasma infection status of Danish swine herds, four ELISAs based on tachyzoite antigen were set up: (1) an indirect ELISA for IgG-antibody; (2) a blocking ELISA for antibody to the membrane antigen, P-30; (3) an indirect ...

  20. Evaluation of four indirect ELISA systems for the detection of trypanosomal antibodies in bovine serum

    International Nuclear Information System (INIS)

    Ndamkou, C.N.; Yomo, J.P.

    2000-01-01

    Four indirect-ELISA systems developed by the Joint FAO/IAEA Division for the detection of trypanosomal antibodies in bovine serum were evaluated in the field. Internal quality control data obtained were good showing that pre-coating plates with antigen increase the robustness of the assay and contribute to its standardisation. ELISA systems derived from Trypanosoma vivax antigen lysates gave a better performance than ELISA systems using T. congolense antigens. Sensitivity and specificity corresponding to the highest accuracy were 86-87% and 83-85% respectively. When comparing the two ELISA systems utilising T. vivax antigens, there was no significant difference between native and denatured antigens and diagnostic threshold was higher for denatured antigens. (author)