WorldWideScience

Sample records for gel immunodiffusion agid

  1. An investigation of enzootic bovine leucosis (EBL) infection by agar gel immunodiffusion (AGID), enzyme linked immunosorbent assay (ELISA) tests and hematological applications on the dairy cows in the

    Kale M.; Öztürk F.

    2004-01-01

    Haematological tests (alfa nafthyl acetate esterase ANAE activity, May Grünwald Giemsa staining and total leucocyte counts) were applied to 469 dairy cows, where the enzootic form of bovine leucosis was investigated. In the same 469 dairy cows, a search for antibodies directed against bovine leucosis virus (BLV) was carried out using agar gel immunodiffusion (AGID) in blood samples and enzyme linked immunosorbent assay (ELISA) in milk samples. Among the 469 animals screened, 90 were positive ...

  2. An investigation of enzootic bovine leucosis (EBL infection by agar gel immunodiffusion (AGID, enzyme linked immunosorbent assay (ELISA tests and hematological applications on the dairy cows in the

    Kale M.

    2004-01-01

    Full Text Available Haematological tests (alfa nafthyl acetate esterase ANAE activity, May Grünwald Giemsa staining and total leucocyte counts were applied to 469 dairy cows, where the enzootic form of bovine leucosis was investigated. In the same 469 dairy cows, a search for antibodies directed against bovine leucosis virus (BLV was carried out using agar gel immunodiffusion (AGID in blood samples and enzyme linked immunosorbent assay (ELISA in milk samples. Among the 469 animals screened, 90 were positive by ELISA and the haematological tests, while 23 were positive by the AGID test. From these results we would advise heavily infected farms to be eliminated. ELISA and haematological methods, in which ANAE activity, May-Grünwald Giemsa staining and total leucocyte counts were used together, were more reliable and sensitive than the AGID test for detecting EBL.

  3. Prevalence of Peste Des Petits Ruminants Virus (PPRV in Mardan, Hangu and Kohat District of Pakistan; Comparative Analysis of PPRV Suspected serum samples using Competitive ELISA (cELISA and Agar Gel Immunodiffusion (AGID

    Misbah Aslam

    2009-06-01

    Full Text Available Peste des petits Ruminants (PPR is an acute, febrile, highly contagious and economically important viral disease of small ruminants. However PPR is more prevalent in sheep and goat. Competitive ELISA, Virus neutrilization test, and RT-PCR are the available techniques for diagnosis of PPR which give rapid detection where as Agar gel immunodiffusion and Counter immunoelectrophoresis were previously used for PPR detection. In this study two serological techniques were compared for PPR diagnosis. The main aim of this study was to evaluate the comparative sensitivity of both techniques for PPR detection. For this purpose one hundred and sixty PPR suspected serum samples collected from goats and sheep flocks (unvaccinated from three Districts of NWFP including Mardan, Hangu and Kohat were analyzed in National Veterinary Laboratories, Islamabad. Out of these 160 samples, fifty (50 were found positive for PPR antibodies with cELISA (Prevalence = 31.25%. The cELISA positive serum samples however gave negative results when tested with AGID although the control well was always positive. Thus it was concluded that cELISA technique is more sensitive and specific than AGID for PPR antibody detection. [Vet. World 2009; 2(3.000: 89-92

  4. Prevalence of Peste Des Petits Ruminants Virus (PPRV) in Mardan, Hangu and Kohat District of Pakistan; Comparative Analysis of PPRV Suspected serum samples using Competitive ELISA (cELISA) and Agar Gel Immunodiffusion (AGID)

    Misbah Aslam; Muhammad Abubakar; Rehana Anjum; Shamim Saleha; and Qurban Ali

    2009-01-01

    Peste des petits Ruminants (PPR) is an acute, febrile, highly contagious and economically important viral disease of small ruminants. However PPR is more prevalent in sheep and goat. Competitive ELISA, Virus neutrilization test, and RT-PCR are the available techniques for diagnosis of PPR which give rapid detection where as Agar gel immunodiffusion and Counter immunoelectrophoresis were previously used for PPR detection. In this study two serological techniques were compared for PPR diagnosis...

  5. Evaluation of agar gel immunodiffusion serology using caprine and ovine lentiviral antigens for detection of antibody to caprine arthritis-encephalitis virus.

    Knowles, D P; Evermann, J F; Shropshire, C; VanderSchalie, J; Bradway, D; Gezon, H M; Cheevers, W P

    1994-01-01

    The sensitivity of the agar gel immunodiffusion (AGID) test for the detection of antibody to caprine arthritis-encephalitis virus (CAEV) was investigated with CAEV or ovine progressive pneumonia virus (OPPV) as the source of antigen. A total of 218 goat serum specimens were tested for anti-CAEV antibody by AGID and immunoprecipitation of [35S]methionine-labeled CAEV. In comparison with that of immunoprecipitation, the sensitivity of the CAEV AGID test was 0.91, and that of the OPPV AGID test ...

  6. Agar gel immunodiffusion assay to detect antibodies to Type A influenza virus.

    Jenson, Terra A

    2014-01-01

    The agar gel immunodiffusion (AGID) test is used to detect antibodies to Type A influenza group-specific antigens, i.e., the ribonucleoprotein (RNP) and matrix (M) proteins. Therefore, this test will detect antibodies to all influenza A virus subtypes. AGID is commonly used to screen poultry flocks for avian influenza virus infection. The AGID is a simple and economical serological test. All serological testing has its advantages and disadvantages which should be considered before choosing the optimal test for the laboratory needs. Each laboratory must evaluate the laboratory's resources, the volume of testing, the goal of testing, how the test results are used and what types of samples are being tested in order to select the optimal test. PMID:24899427

  7. Comparison of agar gel immunodiffusion test, enzyme-linked immunosorbent assay and PCR in diagnostics of enzootic bovine leukosis

    Malovrh Tadej

    2005-01-01

    Full Text Available Bovine leukaemia virus (BLV is a retrovirus that induces a chronic infection in cattle. Once infected, cattle remain virus carriers for life and start to show an antibody response within a few weeks after infection. Eradication and control of the disease are based on early diagnostics and segregation of the carriers. The choice of a diagnostic method depends on the eradication programme, money resources and characteristics of the herd to be analysed. The agar gel immunodiffusion (AGID test has been the serological test of choice for routine diagnosis of serum samples. Nevertheless, in more recent years, the enzyme-linked immunosorbent assay (ELISA has replaced the AGID for large scale testing. For this purpose, commercially available BLV-ELISA kits were compared to the AGID and to the polymerase chain reaction (PCR method performed with two sets of primers, amplifying env region. The ELISA kit based on the p24 core protein was found to be less specific and served as a screening test. The ELISA kit based on the envelope glycoprotein (gpSI served as a verification test and gave a good correlation with the AGID test and PCR method. However, ELISA showed a higher sensitivity than AGID. The p24 based ELiSA was useful for screening a large number of samples, whereas gp51 based ELISA, AGID and PCR were more important for detecting the antibody response against the individual BLV-proteins and therefore for verification of the infection with BLV.

  8. Detection of Aspergillus-specific antibodies by agar gel double immunodiffusion and IgG ELISA in feline upper respiratory tract aspergillosis.

    Barrs, V R; Ujvari, B; Dhand, N K; Peters, I R; Talbot, J; Johnson, L R; Billen, F; Martin, P; Beatty, J A; Belov, K

    2015-03-01

    Feline upper respiratory tract aspergillosis (URTA) is an emerging infectious disease. The aims of this study were: (1) to assess the diagnostic value of detection of Aspergillus-specific antibodies using an agar gel double immunodiffusion (AGID) assay and an indirect immunoglobulin G (IgG) ELISA; and (2) to determine if an aspergillin derived from mycelia of Aspergillus fumigatus, Aspergillus niger and Aspergillus flavus can be used to detect serum antibodies against cryptic Aspergillus spp. in Aspergillus section Fumigati. Sera from cats with URTA (group 1: n = 21) and two control groups (group 2: cats with other upper respiratory tract diseases, n = 25; group 3: healthy cats and cats with non-respiratory, non-fungal illness, n = 84) were tested. Isolates from cats with URTA comprised A. fumigatus (n = 5), A. flavus (n = 1) and four cryptic species: Aspergillus felis (n = 12), Aspergillus thermomutatus (Neosartorya pseudofischeri, n = 1), Aspergillus lentulus (n = 1) and Aspergillus udagawae (n = 1). Brachycephalic purebred cats were significantly more likely to develop URTA than other breeds (P = 0.013). The sensitivity (Se) of the AGID was 43% and the specificity (Sp) was 100%. At a cut-off value of 6 ELISA units/mL, the Se of the IgG ELISA was 95.2% and the Sp was 92% and 92.9% for groups 2 and 3 cats, respectively. Aspergillus-specific antibodies against all four cryptic species were detected in one or both assays. Assay Se was not associated with species identity. Detection of Aspergillus-specific antibodies by IgG ELISA has high Se and Sp for diagnosis of feline URTA. PMID:25634077

  9. Comparison of an agar-gel immunodiffusion test with other serological methods for differentiating Brucella infected from vaccinated cattle.

    McMahon, K. J.

    1983-01-01

    An agar-gel immunodiffusion test was compared with other serological tests for detection of antibodies in the sera of 48 cattle vaccinated with Brucella abortus strain 19. Two hundred forty-two sera were tested over a 12 month period, and addition of positive reactions for each test resulted in totals of 170 for the card test, 74 for the standard tube-agglutination test, 71 for the 2-mercaptoethanol test, 64 for the dithiothreitol test and 22 for the agar-gel immunodiffusion test.

  10. Comparision of Polymerase Chain Reaction and Agar Gel Immunodiffusion test in Detection of MarekAND#8217;s Disease Virus

    A. Manicavasaka Dinakaran

    2010-10-01

    Full Text Available A study was undertaken to identify Marek’s disease virus (MDV antigen by PCR and AGID and to test the significance of PCR and AGID by McNemar’s test in detection of MDV antigen in outbreak in layer flocks. A total of twelve different MD outbreak flocks with varying flock size were selected in this study. Feather follicles were collected from 10 apparently healthy birds, 10 clinically affected birds and 10 dead birds separately in each outbreak. All the samples were subjected to PCR and AGID. In PCR, 42 (35.00%, 68 (56.67% and 106 (88.33% samples were positive to MDV in apparently healthy birds, clinically affected birds and dead birds respectively and in AGID 28 (23.33%, 56 (46.67% and 98 (81.67% samples were positive to MDV in apparently healthy birds, clinically affected birds and dead birds respectively. In testing the significance of PCR and AGID in detecting MDV, significant difference existed between the two tests in feather tips of apparently healthy birds (P < 0.05, whereas there was no significant difference between PCR and AGID in detection of MDV in feather tips of clinically affected and dead birds (P > 0.05. Hence, PCR can be used to screen MDV in apparently healthy birds and AGID can be used to screen MDV in clinically affected and dead birds keeping feasibility and economic consideration. [Vet. World 2010; 3(5.000: 212-214

  11. Use of enzyme immunoassay (ELISA) for monitoring effectiveness of rinderpest vaccination and comparative evaluation with Agar-Gel immunodiffusion test

    In line with other countries participating in the Pan African Rinderpest Campaign, Ghana wishes to monitor the success of a national rinderpest vaccination campaign. This involves the collection of sera from throughout the country in an epidemiologically acceptable manner and the use of a serological procedure that can test the sera for the presence of antibodies to the rinderpest virus. A comparison was carried out between an FAO/IAEA ELISA based system and an Agar-Gel Immunodiffusion test for the detection of antibodies to rinderpest virus in cattle. the ELISA was found to be faster than the Agar-Gel test, could handle larger number of samples in a short time and could detect lower levels than of immunoglobulins. Utilising the ELISA system to examine sera collected in two surveys of 3,500 and 1,818 samples from three regions (Greater Accra, Central and Volta regions) a very marked variable rate of seroconversion was demonstrated with levels lower than the desired 85%. It would appear that the primary cause of these lower than expected levels was related to an inadequate cold-chain. (author). 7 refs, 1 fig., 4 tabs

  12. Comparision of Polymerase Chain Reaction and Agar Gel Immunodiffusion test in Detection of MarekAND#8217;s Disease Virus

    A. Manicavasaka Dinakaran; G. Selvaraju; Jayalakshmi, K.; T.R. Gopalakrishna Murthy; M. Geetha and S. Saravanan

    2010-01-01

    A study was undertaken to identify Marek’s disease virus (MDV) antigen by PCR and AGID and to test the significance of PCR and AGID by McNemar’s test in detection of MDV antigen in outbreak in layer flocks. A total of twelve different MD outbreak flocks with varying flock size were selected in this study. Feather follicles were collected from 10 apparently healthy birds, 10 clinically affected birds and 10 dead birds separately in each outbreak. All the samples were subjec...

  13. Brucella abortus 1119-3 O-chain polysaccharide to differentiate sera from B. abortus S-19-vaccinated and field-strain-infected cattle by agar gel immunodiffusion.

    Cherwonogrodzky, J W; Nielsen, K H

    1988-01-01

    Purified Brucella abortus 1119-3 and Brucella melitensis 16M lipopolysaccharide O-chain polysaccharides were not precipitated in agar gel immunodiffusion by any of 24 sera from vaccinated cattle but were precipitated by 18 of 24 sera from infected cattle. This difference can be used to differentiate sera of cattle vaccinated with B. abortus S-19 from sera of some field-strain-infected cattle.

  14. Effectivity of PCR and AGID methods to detect of enzootic bovine leukosis in Indonesia

    Saepulloh M; Sendow I

    2015-01-01

    Enzootic Bovine Leucosis (EBL) is one of viral diseases in cattle caused by bovine leukemia virus (BLV), from Retroviridae. The virus can be detected using severals methods such as Polymerase Chain Reaction (PCR), while antibody can be detected using Agar Gel Immunodifussion (AGID). The aim of this experiment was to study the effectivity of PCR and AGID methods to detect enzootic bovine leukosis virus in Indonesia. Samples of peripheral blood leukocyte (PBL) were collected from cattles those ...

  15. Effectivity of PCR and AGID methods to detect of enzootic bovine leukosis in Indonesia

    Saepulloh M

    2015-03-01

    Full Text Available Enzootic Bovine Leucosis (EBL is one of viral diseases in cattle caused by bovine leukemia virus (BLV, from Retroviridae. The virus can be detected using severals methods such as Polymerase Chain Reaction (PCR, while antibody can be detected using Agar Gel Immunodifussion (AGID. The aim of this experiment was to study the effectivity of PCR and AGID methods to detect enzootic bovine leukosis virus in Indonesia. Samples of peripheral blood leukocyte (PBL were collected from cattles those with and without showing clinical signs. A total of 307 blood and serum samples were tested against BLV using PCR and AGID tests, while 21 semen samples which were from similar animals for blood collection were collected only for PCR test. The results indicated that twelve cattles have positive results with PCR test in PBL, but from those cattles only seven were positive with AGID. On the other hand, the PCR did not detect EBL in 21 bovine semen samples tested, although one sample gave positive result with PCR in PBL. This results indicated that PCR method from blood samples was more sensitive than that AGID method. The PCR detection was also more sensitive for PBL than that for semen samples

  16. Imunodifusão em gel de ágar com polissacarídeos de membrana de Brucella abortus 1119-3 no diagnóstico da brucelose bovina Membrane polysaccharides of Brucella abortus 1119-3 in agar gel immunodifusion test in diagnosis of bovine brucellosis

    J. Megid

    1999-10-01

    Full Text Available Comparou-se a prova de imunodifusão em gel de ágar (IDGA, utilizando extrato polissacarídico (POLI O, obtido da amostra de B. abortus 1119-3, com os testes de soroaglutinação rápida em placa, de soroaglutinação lenta em tubos, de antígeno acidificado e de 2-mercaptoetanol para o diagnóstico da brucelose bovina. O IDGA mostrou alta especificidade, porém sensibilidade inferior aos métodos convencionais.An agar gel immunodiffusion (AGID test using the polysaccharide (POLIO O extract obtained from Brucella abortus strain 1119-3, was compared to plate agglutination, tube agglutination, rose bengal plate and mercaptoethanol tests in the diagnosis of bovine brucellosis. The AGID assay with B. aborturs polysaccharide antigens, presented a greater specificity but lower sensitivity for detecting brucellosis infected animals as compared to the conventional methods of antibody detection.

  17. Rapid serum agglutination and agar gel immunodiffusion tests associated to clinical signs in rams experimentally infected with Brucella ovis Teste de soro aglutinação rápida e do teste de imunodifusão em gel de ágar associados aos sinais clínicos em carneiros infectados experimentalmente com Brucella ovis

    Cristiane Nakada Nozaki

    2011-08-01

    Full Text Available The purpose of this study was to evaluate the agar gel immunodiffusion and the rapid serum agglutination tests associated to clinical signs in rams experimentally infected with Brucella ovis. The serological profile during the 12 months of infection showed a large fluctuation of antibodies that favors the failure in the diagnostic. The evaluation of tests after the experimental infection allowed to suggest that none of the tests were able to detect the infection throughout the period of study. The study reinforces the importance of considering the clinical signs to support the diagnosis of Brucella ovis infection in rams.O objetivo deste estudo foi avaliar o uso do teste de imunodifusão em gel de ágar e o teste sorológico de aglutinação rápida comparados aos sinais clínicos em carneiros infectados experimentalmente com Brucella ovis para o diagnóstico confirmatório da brucelose ovina. O perfil sorológico durante os 12 meses pós-infecção mostrou flutuação da resposta por anticorpos, que favorece a falha no diagnóstico. A avaliação dos testes indicou que nenhum dos testes foi capaz de detectar a infecção durante todo o período de estudo. O estudo ressalta a importância de considerar os sinais clínicos para apoiar o diagnóstico confirmatório da infecção por Brucella ovis em carneiros.

  18. Use of monoclonal antibodies against avian retroviral protein p19 for competitive radioimmunoassay and immunodiffusion

    Monoclonal antibodies were used in competitive binding assays to investigate the arrangement of three epitopes on protein p19 of the avian myeloblastosis virus (AMV). It is reasoned that if the epitopes recognized by two monoclonal antibodies are physically close, the binding of one antibody will sterically block the binding of the other; conversely no blocking will occur if the epitopes are sufficiently distant. The results of these competitive binding assays demonstrated the presence of two distinct antigenic sites on protein p19. The monoclonal antibodies against protein p19 of AMV were also tested in gel double immunodiffusion. Since p19 protein shows strong tendency to aggregate, it was not surprising that clear precipitin lines with these monoclonal antibodies were obtained. (author)

  19. Estudio comparativo de un PCR anidado, ELISA y AGID en la detección del virus de la leucosis bovina en muestras de suero, sangre y leche Comparative study of nested PCR, ELISA and AGID tests in the detection of bovine leukaemia virus infection in serum, blood and milk samples

    R Felmer

    2006-01-01

    Full Text Available Se evaluaron distintos métodos actualmente disponibles para el diagnóstico de la infección por el virus de la leucosis bovina (VLB. Los métodos empleados fueron AGID en suero, ELISA en muestras de suero y leche y PCR en linfocitos sanguíneos. De un total de 126 animales analizados, AGID identificó un menor número de animales positivos (75 comparado con las pruebas PCR y ELISA aplicadas en muestras de suero y leche (100. Tres animales positivos a AGID fueron negativos a PCR y 28 de las 51 muestras negativas a AGID fueron positivas mediante PCR. La sensibilidad diagnóstica de PCR con respecto a AGID fue de 96%, mientras que la especificidad fue de 45% (kappa 0,45. Todos los animales positivos a AGID fueron también positivos a ELISA aplicado tanto en suero como en leche, mientras que 25 animales negativos a AGID fueron consignados como positivos a ELISA, en ambas muestras biológicas. De esta forma, la sensibilidad diagnóstica de ELISA respecto a AGID fue de un 100%, mientras que la especificidad fue de 51% (kappa 0,55. La menor sensibilidad observada de AGID no es debido a reacciones falso positivas de ELISA y PCR, sino más bien a una mayor sensibilidad de estas últimas, lo que sugiere reconsiderar la utilización del método AGID en aquellos países en que aún se utiliza como método oficial en los programas de erradicación de leucosis.Different methods available for the detection of bovine leukaemia virus (BLV infection were evaluated. The methods evaluated were AGID in serum, ELISA in serum and milk, and PCR in blood lymphocytes. The AGID test identified a smaller number of positive animals (75/126 compared to PCR and ELISA tests (100/126. Three positive animals by AGID were negative by PCR and 28 of the 51 negative samples by AGID were positive by PCR. The sensitivity of PCR with respect to AGID was 96%, whereas the specificity was 45% (kappa 0.45. All positive animals by AGID were also positive by ELISA in serum and milk samples

  20. Estudio comparativo de un PCR anidado, ELISA y AGID en la detección del virus de la leucosis bovina en muestras de suero, sangre y leche Comparative study of nested PCR, ELISA and AGID tests in the detection of bovine leukaemia virus infection in serum, blood and milk samples

    R Felmer; Zúñiga, J.; M Recabal

    2006-01-01

    Se evaluaron distintos métodos actualmente disponibles para el diagnóstico de la infección por el virus de la leucosis bovina (VLB). Los métodos empleados fueron AGID en suero, ELISA en muestras de suero y leche y PCR en linfocitos sanguíneos. De un total de 126 animales analizados, AGID identificó un menor número de animales positivos (75) comparado con las pruebas PCR y ELISA aplicadas en muestras de suero y leche (100). Tres animales positivos a AGID fueron negativos a PCR y 28 de las 51 m...

  1. [Immunodiffusion analysis of plasma proteins in the canine family].

    Baranov, O K; Iurishina, N A; Savina, M A

    1976-01-01

    Immunodiffusion studies have been made on the plasma of 9 species (Vulpes vulpes, V. corsak, Alopex lagopus, Canis aureus, C. lupus, C. familiaris, C. dingo, Nyctereutes procynoides, Fennecus zerde) from the family of Canidae using milk antisera. Unlike rabbit antisera used earlier, milk antisera make it possible to detect more significant antigenic divergency with respect to 5 alpha- and beta-globulins. These globulins seem to have a higher evolution rate of antigenic mosaics as compared to other plasma proteins in the family investigated. The family Canidae serologically may be divided into two main groups: 1) the genus Canis which includes the wolf, domestic dog, dingo, jackal and 2) species which significantly differ from the former (the fox, polar fox, dog fox, fennec). In relation to these two groups, the raccoon dog occupies special position. PMID:62473

  2. Serological monitoring of antibodies for an early diagnosis ofaspergillosis in captive penguins

    Ângela L. Cabana; Xavier, Melissa O.; Vanice Poester; Gabriel B. Klafke; Pedro L. B.Filho; Aryse Martins; Rodolfo P. S.Filho; Meireles, Mário C. A.

    2015-01-01

    Abstract: This study aimed to evaluate the efficacy of detection of anti-Aspergillus fumigatus antibodies in captive penguins by double radial agar gel immunodiffusion (AGID) for the aspergillosis diagnosis. We included 134 Magellanic penguins (Spheniscus magellanicus) in rehabilitation at the Center for Recovery of Marine Animals (CRAM / FURG). All of them were monitored by AGID weekly until its final destination (death or release), totalizing 660 serum samples studied. All animals were clin...

  3. Evaluation of western blotting for the diagnosis of enzootic bovine leukemia Avaliação da técnica de western blot no diagnóstico da leucose enzoótica bovina

    E.T. Gonzalez; G.A. Oliva; Norimine, J; V. Cid de la Paz; M. G. Echeverría

    1999-01-01

    A western blotting (WB) procedure has been developed for detecting antibodies to bovine leukosis virus (BLV) in cattle sera. Two hundred and thirty three serum samples from naturally infected cattle with BLV virus and serial bleedings from experimentally BLV infected cows were used. An agar gel immunodiffusion test (AGID) was used for comparing with the results obtained by WB. The AGID positive sera showed a different degree of reactivity by WB test against the two most important viral antige...

  4. Evaluation of western blotting for the diagnosis of enzootic bovine leukemia

    Gonzalez E.T.; Oliva G.A.; Norimine J.; Cid de la Paz V.; Echeverría M.G.

    1999-01-01

    A western blotting (WB) procedure has been developed for detecting antibodies to bovine leukosis virus (BLV) in cattle sera. Two hundred and thirty three serum samples from naturally infected cattle with BLV virus and serial bleedings from experimentally BLV infected cows were used. An agar gel immunodiffusion test (AGID) was used for comparing with the results obtained by WB. The AGID positive sera showed a different degree of reactivity by WB test against the two most important viral antige...

  5. Amino-terminal sequence analysis of the Coccidioides immitis chitinase/immunodiffusion-complement fixation protein.

    Johnson, S M; Zimmermann, C R; Pappagianis, D

    1993-01-01

    A chitinase isolated from Coccidioides immitis was subjected to amino-terminal protein sequence analysis. The resulting 18-amino-acid sequence was compared with the previously reported amino acid sequence of coccidioidal immunodiffusion-complement fixation (IDCF) antigen. From the homology of the two sequences, the results support the identification of the IDCF antigen with a chitinase.

  6. Does the degree of polymerization of haptoglobin influence the results of the radial immunodiffusion assay?

    van Rijn, H. J M; Wisman, J.P.W.; Meyling, F G

    1987-01-01

    The degree of polymerization of haptoglobin (Hp) phenotypes 2-1 and 2-2 was studied. In individual samples the degree of polymerization tends to be positively correlated with the Hp concentration as determined by the radial immunodiffusion technique (RID), while an inverse relationship between the size of Hp polymers and the Hp concentration in RID was expected. After reductive cleavage of Hp, the apparent Hp concentration became higher in individual samples with different degrees of polymeri...

  7. Bluetongue virus: comparative evaluation of enzyme-linked immunosorbent assay, immunodiffusion, and serum neutralization for detection of viral antibodies.

    Poli, G.; Stott, J.; Liu, Y. S.; Manning, J S

    1982-01-01

    Comparative studies on the detection of bovine serum immunoglobulin G antibodies to bluetongue virus with an enzyme-linked immunosorbent assay, an immunodiffusion method, and a serum neutralization assay demonstrated complete concordance between the enzyme-linked immunosorbent assay and the serum neutralization assay results. However, the immunodiffusion method failed to detect bluetongue virus antibody in a substantial number of sera found to possess bluetongue virus immunoglobulin G with th...

  8. Evaluation of standard reagents for radial-immunodiffusion assays : In vitro control of rabies vaccines

    MICELI Graciela S.; TORROBA Jorge; TORRES Walter; ESTEVES MADERO Jorge; DÍAZ Ana Maria

    2000-01-01

    The RID assay is one of the in vitro methods used for in-process control in the production of rabies vaccines for veterinary use. It has been shown to be very useful for determining antigen concentration in the final bulk product. The work presented in this paper, including the production and standardization of candidate standard reagents for use in the Radial Immunodiffusion Assay (RID) was carried out at the Pan American Institute for Food Protection and Zoonoses (INPPAZ/PAHO/WHO). The stud...

  9. Prevalence of maedi-visna infection in culled ewes in Alberta

    Fournier, Dominique; Campbell, John R.; Middleton, Dorothy M.

    2006-01-01

    Maedi-visna (MV) is a relatively common chronic infection of sheep in North America resulting in economic loss to the sheep industry. The objectives of this study were to: 1) measure the prevalence of MV infection in culled ewes in Alberta, by histologic examination (lungs and udder) and serologic testing using an agar gel immunodiffusion (AGID) test, 2) examine any geographic differences in its prevalence in the province, 3) evaluate the level of agreement between histopathologic examination...

  10. An investigation of equine infectious anaemia infection in the Central Anatolia region of Turkey

    O. Yapkic

    2007-05-01

    Full Text Available In this study, 162 horses, 80 donkeys and 51 mule serum samples were collected in Konya city. Additionally, 64 horse serum samples from Ankara and 49 samples from Kayseri city were included in the study. A total of 406 serum samples were examined by agar gel immunodiffusion (AGID and enzyme-linked immunosorbent assay (ELISA for antibody to equine infectious anaemia virus (EIAV and no positive result was detected.

  11. EPIDEMIOLOGIA DA INFECÇÃO PELO VÍRUS DA LEUCOSE ENZOÓTICA BOVINA (LEB)

    José Wilton Pinheiro Junior; Maria Evódia de Souza; Wagnner José Nascimento Porto; Nair Silva Cavalcanti Lira; Rinaldo Aparecido Mota

    2013-01-01

    The purpose of this study was to investigate the presence of anti-enzootic leucosis virus antibodies and also to identify the association between seropositivity and management variables for this infection in cattle in the State of Alagoas, Brazil. A total of 17 herds were examined, totaling 341 animals, distributed in eight counties. The antibody detection was performed by the technique of agar gel immunodiffusion (AGID), using the antigen constituted of lipids and proteins from bovine leukos...

  12. Comparison of immunodiffusion and enzyme linked immunosorbent assay in the detection of abnormal antibodies in pigeon breeder's disease.

    Simpson, C.; Shirodaria, P V; J. P. Evans; Simpson, D I; Stanford, C F

    1992-01-01

    AIMS: To compare the sensitivity of two methods for the detection of serum antibodies to pigeon faecal antigens in patients with pigeon breeder's disease. METHODS: Serum samples stored at -20 degrees C from 50 patients with pigeon breeder's disease, 50 control samples from patients with other respiratory diseases, and 50 healthy blood donors were examined for the precipitating antibodies and IgG antibodies to antigens present in extract of pigeon droppings by immunodiffusion and enzyme linked...

  13. Evaluation of standard reagents for radial-immunodiffusion assays. In vitro control of rabies vaccines

    MICELI Graciela S.

    2000-01-01

    Full Text Available The RID assay is one of the in vitro methods used for in-process control in the production of rabies vaccines for veterinary use. It has been shown to be very useful for determining antigen concentration in the final bulk product. The work presented in this paper, including the production and standardization of candidate standard reagents for use in the Radial Immunodiffusion Assay (RID was carried out at the Pan American Institute for Food Protection and Zoonoses (INPPAZ/PAHO/WHO. The study was completed with the cooperation of the Faculty of Veterinary Sciences, National University of La Plata (NULP, Argentina, where the validation of the proposed standards and the quality control of samples from 28 different batches of rabies vaccines produced with Pasteur strain rabies virus (PV in BHK cells were performed. The activity of the vaccines was determined by in vivo (NIH and in vitro (RIDassays. The results of the candidate reagents for the reagent standardization tests showed stability, sensitivity and reproducibility. The Relative Potency the 1.2 between the problem vaccines and the reference vaccine was estimated by variance and regression analysis. The results of our validation study show that the INPPAZ (PAHO/WHO is capable of producing and distributing the above-mentioned standard reagents, as well as of providing support for the incorporation of the RID technique (sensitive, rapid and inexpensive to the laboratories that manufacture rabies vaccines in Latin America and the Caribbean.

  14. Evaluation of standard reagents for radial-immunodiffusion assays. In vitro control of rabies vaccines.

    Miceli, G S; Torroba, J; Torres, W; Esteves Madero, J; Díaz, A M

    2000-01-01

    The RID assay is one of the in vitro methods used for in-process control in the production of rabies vaccines for veterinary use. It has been shown to be very useful for determining antigen concentration in the final bulk product. The work presented in this paper, including the production and standardization of candidate standard reagents for use in the Radial Immunodiffusion Assay (RID) was carried out at the Pan American Institute for Food Protection and Zoonoses (INPPAZ/PAHO/WHO). The study was completed with the cooperation of the Faculty of Veterinary Sciences, National University of La Plata (NULP), Argentina, where the validation of the proposed standards and the quality control of samples from 28 different batches of rabies vaccines produced with Pasteur strain rabies virus (PV) in BHK cells were performed. The activity of the vaccines was determined by in vivo (NIH) and in vitro (RID)assays. The results of the candidate reagents for the reagent standardization tests showed stability, sensitivity and reproducibility. The Relative Potency the 1.2 between the problem vaccines and the reference vaccine was estimated by variance and regression analysis. The results of our validation study show that the INPPAZ (PAHO/WHO) is capable of producing and distributing the above-mentioned standard reagents, as well as of providing support for the incorporation of the RID technique (sensitive, rapid and inexpensive) to the laboratories that manufacture rabies vaccines in Latin America and the Caribbean. PMID:10887375

  15. Evaluation of western blotting for the diagnosis of enzootic bovine leukemia

    Gonzalez E.T.

    1999-01-01

    Full Text Available A western blotting (WB procedure has been developed for detecting antibodies to bovine leukosis virus (BLV in cattle sera. Two hundred and thirty three serum samples from naturally infected cattle with BLV virus and serial bleedings from experimentally BLV infected cows were used. An agar gel immunodiffusion test (AGID was used for comparing with the results obtained by WB. The AGID positive sera showed a different degree of reactivity by WB test against the two most important viral antigens (gp51 and p24, or against one of them. Other proteins (gp30, p15, p12 and p10 were not detected with any AGID positive sera, being observed occasionally three bands corresponding to the p24 protein. Using sera obtained by BLV experimental inoculation, the antibodies directed to p24 appeared early (between the 2nd and 4th week post inoculation and thereafter antibodies to gp51were detected in some animals. The analysis of field serum samples by AGID as compared to WB showed an agreement of 90.9%. Only 1.7% of sera were negative by AGID and positive by WB and 7.2% that were not conclusive by AGID and were defined by WB (4.2% as positive and 3.0% as negative.

  16. Improved methods for the fluorographic detection of weak β-emitting radioisotopes in agarose and acrylamide gel electrophoresis media

    The use of acetic acid as a solvent for diphenyloxazole (PPO) in fluorographic procedures has been investigated. It is demonstrated to be superior to both dimethyl sulfoxide and methanol with respect to its suitability in both agarose and acrylamide gel electrophoresis systems. In addition, a method has been developed for impregnating fragile gels such as those used for immunodiffusion with PPO in preparation for fluorography. (Auth.)

  17. Serological monitoring of antibodies for an early diagnosis ofaspergillosis in captive penguins

    Ângela L. Cabana

    2015-06-01

    Full Text Available Abstract: This study aimed to evaluate the efficacy of detection of anti-Aspergillus fumigatus antibodies in captive penguins by double radial agar gel immunodiffusion (AGID for the aspergillosis diagnosis. We included 134 Magellanic penguins (Spheniscus magellanicus in rehabilitation at the Center for Recovery of Marine Animals (CRAM / FURG. All of them were monitored by AGID weekly until its final destination (death or release, totalizing 660 serum samples studied. All animals were clinically accompanied and post-mortem examinations was performed in penguins that died during the studied period. A total of 28% (37/134 of the penguins died, 89.2% (33/37 due to aspergillosis, 11% (4/37 by other causes and 97 were released. From the 33 animals with proven aspergillosis, 21 presented anti- A. fumigatus antibodies by AGID, being the average interval between death and positive AGID 16.4 days. Twelve animals with negative serology died of aspergillosis. The sensitivity and specificity rates were 63.6% and 95% respectively, and the positive and negative predictive values were 80.7% and 88.9% respectively. These data demonstrate that the serological monitoring for detection of antibodies by AGID can be an important tool for the diagnosis of aspergillosis in penguins.

  18. Epidemiological studies on bluetongue virus infection in West Java, Indonesia

    In monitoring of sentinel cattle in West Java, seroconversions to orbiviruses occurred mostly at the end of the wet season. A low altitude site gave more reactors than did a high altitude site. Due to perceived inefficiencies of the agar gel immunodiffusion (AGID) test, a competitive ELISA (C-ELISA) was applied and the results compared with the AGID test results. C-ELISA detected antibodies at an earlier stage of infection than did the AGID test. Not all sera reacting in the AGID test reacted in C-ELISA, suggesting that the C-ELISA is more specific in detecting bluetongue virus (BTV) antibodies than the AGID. However, as the infection status of most field sera was not known, this could not be confirmed conclusively from the available data. A comparison of isolation methods indicated that isolates were obtained more frequently if samples were passaged in embryonated eggs before blind passage in A edes albopictus cells followed by passage in BHK-21 cells. Six BTV serotypes, 1,7,9,12,20,21 and 23 were identified and confirmed from apparently healthy sentinel cattle blood at low altitudes; BTV serotype 21 was also isolated from a pool of the Avaritia sub-genus of the Culicoides spp which contained 227 C. fulvus and 20 C. orientalis. (author). 17 refs, 2 figs, 1 tab

  19. A comparative study of antigens of Aspergillus fumigatus isolates from patients and soil of ornamental plants in the immunodiffusion test.

    Staib, F; Folkens, U; Tompak, B; Abel, T; Thiel, D

    1978-11-01

    The strikingly frequent and constant presence of Aspergillus fimigatus in the soil of potted ornamental plants kept in private houses and hospitals has been the reason for studying the antigens of the strains found from the diagnostic and epidemiological angles. Culture-filtrate antigens of A. fumigatus strains isolated from the soil of 4 different ornamental plants, epiphyllum (Epiphyllum truncatum), orange tree (Citrus sinensis), Alpine rose (Azalea indica) and Christmas flower (Euphorbia pulcherrima), were compared, in the immunodiffusion test, with antigens of A. fumigatus strains from aspergillosis patients prepared in an identical way. When tested against 8 different sera from different aspergillosis patients there was a good coincidence of results. Control sera from patients suffering from diseases other than aspergillosis, no false-positive reactions could be observed. The findings are discussed in respect of diagnosis and epidemiology. PMID:83753

  20. Quantitation of IgE by means of a modified radial immunodiffusion method in comparison with the radioimmunosorbent test (RIST)

    Serum IgE were quantitied by means of modified radial immunodiffusion technique (RID). To improve visibility of precipitin bands a staining procedure with DOPA was applied. Pretreatment of sera with dextransulfate proved necessary in order to avoid unspecific ringformation in the agargel. In comparison with the RIST it turned out that sera containing less than 500 I.U. IgE/ml did not produce precipitin bands with this method. Sera containing 500-999 I.U. IgE/ml occasionally exhibited positive results with the RID technique, whereas sera with more than 1,000 I.U./ml were regulary positive. In its present form the RID may be used as screening method for sera with higher IgE levels. Within the above mentioned limits the IgE levels calculated by means of the RID-test roughly corresponded the values determined by the RIST. (orig.)

  1. [Express diagnostics of bovine leucosis by immune sensor based on surface plasmon resonance].

    Pyrohova, L V; Starodub, M F; Artiukh, V P; Nahaieva, L I; Dobrosol, H I

    2002-01-01

    An immune sensor based on the surface plasmon resonance (SPR) was developed for express diagnostics of bovine leucosis. The sensor was used for detection of the level of antibodies against bovine leukaemia virus (BLV) in the blood serum. The industrially manufactured BLV antigen for screening test in the agar gel immunodiffusion (AGID) required the additional purification in order to be used in immune sensor analysis. It was shown that immune sensor analysis was more sensitive, rapid and simple in comparison with the traditional AGID test. It was stated that the developed immune sensor was capable to be used for performance of bovine leucosis screening at the farms and the minimal dilution of the serum should be 1:500. PMID:12916242

  2. SOROEPIDEMIOLOGIA DA LEUCEMIA BOVINA (LB EM BOVINOS CURRALEIROS DOS ESTADOS DE GOIÁS E TOCANTINS, BRASIL

    Raquel Soares Juliano

    2014-09-01

    Full Text Available Aiming to verify bovine leukaemia (BL occurrence in Curraleiro cattle breed, sera of 1051 animals were sampled from Goias (n=11 and Tocantins (n=12 states. BL serological diagnosis was performed by agar gel immunodiffusion method (AGID. The total occurrence rate was 21.1% (222/1051. In Tocantins it was 27.8% (136/489 occurrence was observed, higher value than in Goias, where 15.3% (86/562 occurrence was found. The serum reactivity was higher in females than in males, 23.3% (198/852 and 11.8% (23/195, respectively, and in animals older than 48 months old.

  3. Prevalence of enzootic bovine leukosis in the Republic of Bulgaria in 1997-2004

    Sandev, Nikolay; Ilieva, Darinka; Sizov, Ignat; Rusenova, Nikolina; ILIEV, Emil

    2006-01-01

    The serological investigations using the agar gel immunodiffusion (AGID) test performed in the Republic of Bulgaria in the period 1997-2004 showed a high prevalence of enzootic bovine leukosis (EBL), from 8.47% in 1997 to 22.26% in 2004. The highest percentage of seroreagents was observed in the regions of Silistra (48.61%), Dobrich (47.57%) and Burgas (47.32%), with the lowest, in the regions of Pazardjik (0.28%), Kyustendil (1.89%) and Smolyan (1.95%). Leukosis infection was found to be mor...

  4. Use of the Polymerase Chain Reaction in the Detection of Bovine Leukosis

    Kelly, Emma Jane

    1992-01-01

    A diagnostic test for bovine leukosis was developed using the polymerase chain reaction (PCR) to amplify a 375 base pair region in the gag gene of the proviral genome. Blood samples were collected from 3 adult Holstein cows shown to be infected with bovine leukosis virus (BLV) by the agar-gel immunodiffusion (AGID) technique. The 3 samples were mixed and the composite blood was used to inoculate 10 cows. Five of the cows were inoculated with 0.1 ml of blood, and the other cows were inocula...

  5. Prevalence of antibodies to type A influenza virus in wild avian species using two serologic assays

    Brown, Justin D.; Luttrell, M. Page; Berghaus, Roy D.; Kistler, Whitney; Keeler, Shamus P.; Howey, Andrea; Wilcox, Benjamin; Hall, Jeffrey; Niles, Larry; Dey, Amanda; Knutsen, Gregory; Fritz, Kristen; Stallknecht, David E.

    2010-01-01

    Serologic testing to detect antibodies to avian influenza (AI) virus has been an underused tool for the study of these viruses in wild bird populations, which traditionally has relied on virus isolation and reverse transcriptase-polymerase chain reaction (RT-PCR). In a preliminary study, a recently developed commercial blocking enzyme-linked immunosorbent assay (bELISA) had sensitivity and specificity estimates of 82% and 100%, respectively, for detection of antibodies to AI virus in multiple wild bird species after experimental infection. To further evaluate the efficacy of this commercial bELISA and the agar gel immunodiffusion (AGID) test for AI virus antibody detection in wild birds, we tested 2,249 serum samples collected from 62 wild bird species, representing 10 taxonomic orders. Overall, the bELISA detected 25.4% positive samples, whereas the AGID test detected 14.8%. At the species level, the bELISA detected as many or more positive serum samples than the AGID in all 62 avian species. The majority of positive samples, detected by both assays, were from species that use aquatic habitats, with the highest prevalence from species in the orders Anseriformes and Charadriiformes. Conversely, antibodies to AI virus were rarely detected in the terrestrial species. The serologic data yielded by both assays are consistent with the known epidemiology of AI virus in wild birds and published reports of host range based on virus isolation and RT-PCR. The results of this research are also consistent with the aforementioned study, which evaluated the performance of the bELISA and AGID test on experimental samples. Collectively, the data from these two studies indicate that the bELISA is a more sensitive serologic assay than the AGID test for detecting prior exposure to AI virus in wild birds. Based on these results, the bELISA is a reliable species-independent assay with potentially valuable applications for wild bird AI surveillance.

  6. Sero-Survey of Equine Infectious Anemia in the Sultanate of Oman during 2007-2009

    Mohammed Body, Abdulmajeed Al-Rawahi, M. Hammad Hussain*, Khalisa Al-Lamki, Saif Al-Habsy, Mahir Almaawali and Qais Abdullah Alrawahi

    2011-06-01

    Full Text Available Equine infectious anemia (EIA is a fatal and relapsing infectious disease of equines caused by the lentivirus of Retroviridae family which occurs world-wide. It tends to become an inapparent infection if death does not result from the acute clinical attack. The virus persists in infected animals for life and can be detected by serological tests like enzyme-linked immunosorbent assay (ELISA and agar gel immunodiffusion (AGID tests. Keeping in view the importance of EIA, a sero-survey and passive surveillance was designed to establish the status of EIA in Oman. For the current study, ELISA was carried out on 331 random horse serum samples collected from all over Oman and 262 serum samples submitted from race horses. Four (0.67% out of total 593 serum samples were found positive on ELISA. These samples were further tested by agar gel immunodiffusion (AGID test for the confirmation and were found negative. Based on the analysis of the samples, it can be assumed that the horse population in the Sultanate was free of the disease during the study period (2007-2009.

  7. Detection of rubella-specific serum IgG and IgA and nasopharyngeal IgA responses using a radioactive single radial immunodiffusion technique

    A radioactive, single radial immunodiffusion technique (RSRID) employing 125I-labelled antiglobulins, was developed to determine rubella-specific serum IgG and IgA and nasopharyngeal IgA antibody responses following both naturally acquired rubella and vaccination with four attenuated vaccines. Rubella-specific IgG antibodies developed in parallel with haemagglutination inhibiting (HAI) antibodies and both persisted for at least a year in all cases of naturally acquired and vaccine induced infection. However, the RSRID test detected rises in titre in all of five volunteers challenged intranasally with RA27/3, whereas only one volunteer showed a rise by HAI. Serum IgA antibodies generally persisted for at least a year following naturally acquired infection but rubella vaccines induced variable responses. Thus, following administration of RA27/3 and To-336 vaccines, rubella-specific IgA usually persisted for a year, whereas Cendehill vaccine failed to induce a detectable response. Rubella-specific nasopharyngeal IgA was detected in all five patients following naturally acquired infection and was still present in the only two patients tested a year after infection. These antibodies were detected in fourteen of twenty-three vaccinees at 3 weeks, but persisted for a year in only two vaccinees, both of whom were given RA27/3 intranasally. (author)

  8. The use of ELISA and nucleic acid hybridization tests in research and diagnosis of bovine leukosis virus

    Enzootic bovine leukosis (EBL) is a disease that affects adult cattle although animals can carry the virus without showing any clinical symptoms. An initial survey in Cuba using the agar gel immunodiffusion test (AGID) revealed that only 15% of the animals on the island were infected and it was therefore decided to undertake a control and eradication campaign. However, prior to the onset of this campaign it was felt necessary to examine a variety of more modern diagnostic procedures to determine which might be most applicable. For the detection of antibodies an ELISA system based on the use of SUMA (a micro-analytical system developed in Cuba) was compared with the AGID and syncytia inhibition test and found to be more sensitive than AGID and far more suitable for large-scale use than either of the other two. For detection of viral proteins the ELISA was compared with a reverse transcriptase assay and the use of immunoperoxidase staining. The latter two methods detected viral proteins in over 50% more samples than the ELISA and although the ELISA is more simple than either of the other to assays when used routinely, its low sensitivity would preclude its use in an eradication programme. (author). 10 refs, 4 tabs

  9. Development of single-chain Fv against the nucleoprotein of type A influenza virus and its use in ELISA.

    Sengupta, Devyani; Shaikh, Asma; Bhatia, S; Pateriya, A K; Khandia, R; Sood, R; Prakash, A; Pattnaik, B; Pradhan, H K

    2014-11-01

    Single chain fragment variable (ScFv) antibodies specific to the nucleoprotein (NP) of avian influenza virus (AIV) were developed using a phage display system. The variable heavy (VH) and the variable light (VL) chain gene fragments were derived from spleen cells of Balb/c mouse immunized with a recombinant NP (rNP) antigen (∼63 kDa) of H5N1 influenza virus. The VH and the VL DNA fragments were assembled through a flexible linker DNA to generate ScFv DNA that was cloned subsequently in a phagemid to express ScFv protein in Escherichia coli cells. The specific reactivity of the ScFv with the rNP antigen and viral antigen (H5N1) was confirmed by Western blot and ELISA. A competitive inhibition ELISA (CI-ELISA) was developed using the rNP and the anti-NP ScFv for detection of type-specific antibodies to AIV in chicken sera. The ScFv based CI-ELISA was compared with hemagglutination inhibition (HI) test and agar gel immunodiffusion (AGID) test over 850 sera. Sensitivity of the CI-ELISA was 100% with HI and AGID and specificity was 98.7% with HI and 100% with AGID. PMID:25152529

  10. Isolation and adaptation of bovine herpes virus Type 1 in embryonated chicken eggs and in Madin–Darby bovine kidney cell line

    Devprabha Samrath

    2016-02-01

    Full Text Available Aim: Objective of the present study was to isolate bovine herpes virus Type 1 (BHV-1 from semen of infected bull and to adapt it onto embryonated eggs and Madin–Darby bovine kidney (MDBK cell line. Further, the virus was identified by agar gel immunodiffusion (AGID test. Materials and Methods: Semen samples were collected from five BHV-1 positive bulls previously confirmed for the presence of antibodies against BHV-1 using avidin-biotin enzyme linked immunosorbent assay test. The virus from semen samples was adapted in chorioallantoic membrane (CAM of 11-day-old embryonated chickens eggs and in MDBK cell line. The presence of BHV-1 in infected CAM and cell culture fluid was confirmed by AGID test. Results: Virus infected CAM showed edema, congestion and thickening at first passage level. Small foci ranged from 1 to 2 mm in diameter, scattered all over the membrane were observed at first passage. More severe changes were observed in CAM after serial passaging. The large pock lesions, round in shape with opaque raised edge and depressed gray central area of necrosis ranged from 3 to 5 mm in diameter were developed at fourth passage. Blind passages in MDBK cell culture were made. The MDBK cell line at second passage level showed characteristic cytopathic effect viz. rounding of cells with shrinkage, followed by aggregation or clumping of cells which progressed rapidly and appeared as “bunch of grapes” at 72 h post inoculation. Few cells become elongated when compared with uninfected controls. A homogenate of CAM with distinct pock lesions and infected cell culture fluid developed precipitation line within 48 h against specific anti-BHV-1 immune serum by AGID test. Conclusion: BHV-1 was easily adapted in CAM of chicken embryos and in MDBK cell line. Virus infected CAM and cell culture fluid showed precipitin band by AGID test.

  11. Isolation and adaptation of bovine herpes virus Type 1 in embryonated chicken eggs and in Madin–Darby bovine kidney cell line

    Samrath, Devprabha; Shakya, Sanjay; Rawat, Nidhi; Gilhare, Varsha Rani; Singh, Fateh

    2016-01-01

    Aim: Objective of the present study was to isolate bovine herpes virus Type 1 (BHV-1) from semen of infected bull and to adapt it onto embryonated eggs and Madin–Darby bovine kidney (MDBK) cell line. Further, the virus was identified by agar gel immunodiffusion (AGID) test. Materials and Methods: Semen samples were collected from five BHV-1 positive bulls previously confirmed for the presence of antibodies against BHV-1 using avidin-biotin enzyme linked immunosorbent assay test. The virus from semen samples was adapted in chorioallantoic membrane (CAM) of 11-day-old embryonated chickens eggs and in MDBK cell line. The presence of BHV-1 in infected CAM and cell culture fluid was confirmed by AGID test. Results: Virus infected CAM showed edema, congestion and thickening at first passage level. Small foci ranged from 1 to 2 mm in diameter, scattered all over the membrane were observed at first passage. More severe changes were observed in CAM after serial passaging. The large pock lesions, round in shape with opaque raised edge and depressed gray central area of necrosis ranged from 3 to 5 mm in diameter were developed at fourth passage. Blind passages in MDBK cell culture were made. The MDBK cell line at second passage level showed characteristic cytopathic effect viz. rounding of cells with shrinkage, followed by aggregation or clumping of cells which progressed rapidly and appeared as “bunch of grapes” at 72 h post inoculation. Few cells become elongated when compared with uninfected controls. A homogenate of CAM with distinct pock lesions and infected cell culture fluid developed precipitation line within 48 h against specific anti-BHV-1 immune serum by AGID test. Conclusion: BHV-1 was easily adapted in CAM of chicken embryos and in MDBK cell line. Virus infected CAM and cell culture fluid showed precipitin band by AGID test. PMID:27051213

  12. Predictive value of serologic tests in the diagnosis and follow-up of patients with paracoccidioidomycosis

    Luz Elena Cano

    1987-10-01

    Full Text Available A serologic study was undertaken in a group of 43 patients with active paracoccidioidomycosis who were treated in the same form (ketoconazole, for identical periods of time (6 months, and folio wed-up for various periods posttherapy. The tests employed were agar gel immunodiffusion (AGID and complement fixation (FC. Also studied were 50 sera from patients with proven histoplasmosis and pulmonary aspergilloma, 30 patients with culturaly proven tuberculosis as well as 92 specimens from healthy individuals, residents in the endemic area for paracoccidioidomycosis. A single lot of yeast filtrate antigen was used throughout the study. The value of each test was measured according to GALEN and GAMBINO6. Both tests were highly sensitive, 89 and 93% respectively. Regarding their specificity, the AGID was totally specific while the CF exhibited 96.6% and 97% specificity in front of tuberculosis patients and healthy individuals respectively and 82% in comparison with patients with other mycoses. The concept of predictive value, that is, the certainty one has in accepting a positive test as diagnostic of paracoccidioidomycosis, favored the AGID procedure (100% over the CF test. The latter could sort out with 93% certainty a patient with paracoccidioidomycosis among a group of healthy individuals and with 97.5% in the case of TB patients; when the group in question was composed by individuals with other deep mycoses, such certainty was lower (81%. The above results indicate that both the AGID and the CF tests furnish results of high confidence; one should not relay, however, in the CF alone as a means to establish the specific diagnosis of paracoccidioidomycosis.

  13. Development of a mixed antigen agar gel enzyme assay (AGEA) for the detection of antibodies to poxvirus in chicken and turkey sera.

    Tadese, Theodros; Potter, E A; Reed, W M

    2003-02-01

    A mixed-antigen agar gel enzyme assay (AGEA) was developed to detect antibodies to poxviruses in chicken and turkey sera. The assay combines the principles of immunodiffusion and enzyme assay. For the detection of antibodies to fowl poxvirus (FP), pigeon poxvirus (PP) and turkey poxvirus (TP) in turkey serum samples, the three antigens were combined to form a mixed-antigen assay. To screen for antibodies to FP and PP in chicken serum samples, the two antigens were combined. When FP and PP viruses were combined as antigens, the sensitivity for chicken sera was 64% but the sensitivity of the agar gel precipitation test (AGPT) was 34% (PAGEA had a sensitivity of 66.4% while that of AGPT was 25% (P<0.001). PMID:12655123

  14. Transport Phenomena in Gel

    Masayuki Tokita

    2016-05-01

    Full Text Available Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed.

  15. GelTouch

    Miruchna, Viktor; Walter, Robert; Lindlbauer, David;

    2015-01-01

    We present GelTouch, a gel-based layer that can selectively transition between soft and stiff to provide tactile multi-touch feedback. It is flexible, transparent when not activated, and contains no mechanical, electromagnetic, or hydraulic components, resulting in a compact form factor (a 2mm thin...... touchscreen layer for our prototype). The activated areas can be morphed freely and continuously, without being limited to fixed, predefined shapes. GelTouch consists of a poly(N-isopropylacrylamide) gel layer which alters its viscoelasticity when activated by applying heat (>32 C). We present three different...

  16. CONFORMANCE IMPROVEMENT USING GELS

    Randall S. Seright

    2003-09-01

    This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the

  17. Control and eradication programme of enzootic bovine leucosis (EBL) from selected dairy herds in Turkey.

    Burgu, I; Alkan, F; Karaoglu, T; Bilge-Dagalp, S; Can-Sahna, K; Güngör, B; Demir, B

    2005-07-01

    Serum samples of 15,909 cattle from 31 dairy herds located in various regions of Turkey were tested for the presence of antibodies against bovine leucosis virus (BLV) using Agar Gel Immuno-diffusion technique (AGID). 48.3% (15/31) of the herds had seropositive animals and positivity rates were detected from 0.5-34.4% in these herds. In an EBL control/eradication programme all seropositive animals were culled in the infected herds. Thereafter, a total of 74,347 sera were tested for the presence of BLV specific antibodies. The serological results and detail of EBL control/eradication programme were shown in this paper. PMID:16124702

  18. Rapid solid-phase radioimmunoassay for detection of equine infectious anemia viral antigen and antibodies: parameters involved in standardization

    Solid-phase radioimmunoassays (SPRIA) are described for the detection of equine infectious anemia (EIA) viral antigen and antibodies. Protein-antigen P29 currently used in the agar-gel immunodiffusion (AGID) test was used as antigen in the SPRIA. The specificity of the reaction was assessed by inhibition with the antigen. The reaction of immune serum against EIA-virus antigen adsorbed to the wells, was completely inhibited by the antigen in solution. This property was applied in an indirect competitive SPRIA for the detection of viral protein P29. The detection threshold of the SPRIA for EIA virus protein was about 5 ng and about 1 ng of antibody can be detected. The assay is rapid, specific and sensitive and allows the testing of multiple serum samples with the advantage of employing a single secondary labelled antibody. (orig.)

  19. Conformance Improvement Using Gels

    Seright, Randall S.; Schrader, Richard; II Hagstrom, John; Wang, Ying; Al-Dahfeeri, Abdullah; Gary, Raven; Marin; Amaury; Lindquist, Brent

    2002-09-26

    This research project had two objectives. The first objective was to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective was to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil.

  20. Crystallization from Gels

    Narayana Kalkura, S.; Natarajan, Subramanian

    Among the various crystallization techniques, crystallization in gels has found wide applications in the fields of biomineralization and macromolecular crystallization in addition to crystallizing materials having nonlinear optical, ferroelectric, ferromagnetic, and other properties. Furthermore, by using this method it is possible to grow single crystals with very high perfection that are difficult to grow by other techniques. The gel method of crystallization provides an ideal technique to study crystal deposition diseases, which could lead to better understanding of their etiology. This chapter focuses on crystallization in gels of compounds that are responsible for crystal deposition diseases. The introduction is followed by a description of the various gels used, the mechanism of gelling, and the fascinating phenomenon of Liesegang ring formation, along with various gel growth techniques. The importance and scope of study on crystal deposition diseases and the need for crystal growth experiments using gel media are stressed. The various crystal deposition diseases, viz. (1) urolithiasis, (2) gout or arthritis, (3) cholelithiasis and atherosclerosis, and (4) pancreatitis and details regarding the constituents of the crystal deposits responsible for the pathological mineralization are discussed. Brief accounts of the theories of the formation of urinary stones and gallstones and the role of trace elements in urinary stone formation are also given. The crystallization in gels of (1) the urinary stone constituents, viz. calcium oxalate, calcium phosphates, uric acid, cystine, etc., (2) the constituents of the gallstones, viz. cholesterol, calcium carbonate, etc., (3) the major constituent of the pancreatic calculi, viz., calcium carbonate, and (4) cholic acid, a steroidal hormone are presented. The effect of various organic and inorganic ions, trace elements, and extracts from cereals, herbs, and fruits on the crystallization of major urinary stone and gallstone

  1. Preparation of chitosan gel

    Lagerge S.

    2012-06-01

    Full Text Available Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  2. CONFORMANCE IMPROVEMENT USING GELS

    Randall S. Seright

    2004-09-30

    This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate

  3. Serologic survey of brucellosis in captive neotropical wild carnivores in northeast Brazil.

    Oliveira-Filho, Edmilson F; Pinheiro, José W Junior; Souza, Marcília M A; Santana, Vânia L A; Silva, Jean C R; Mota, Rinaldo A; Sá, Fabricio B

    2012-06-01

    Abstract. This study reports the detection of antibodies against Brucella abortus and B. canis in wild neotropical carnivores kept in captivity in three zoos in northeastern Brazil. A total of 42 serum samples were examined, 17 from coatis (Nasua nasua), eight from crab-eating raccoons (Procyon cancrivorus), three from crab-eating foxes (Cerdocyon thous), three from hoary foxes (Lycalopex vetulus), two from little spotted cats (Leopardus tigrinus), five from tayras (Eira barbara), two from greater grisons (Galictis vittata), and two from neotropical river otters (Lontra longicaudis). The Rose-Bengal test and complement fixation test (CFT) were performed to detect anti-Brucella spp. antibodies, whereas the agar gel immunodiffusion test (AGID) was employed to detect anti-B. canis antibodies. The overall seroprevalence varied by species and by test; in addition, CFT and AGID seemed better able to detect antibodies against B. abortus and B. canis, respectively. This is the first study on the presence of anti-Brucella spp. antibodies in captive carnivores from Brazil, as well as the first report of antibodies to Brucella spp. in coatis, crab-eating raccoons, hoary foxes, little spotted cats, tayras, and greater grisons. PMID:22779245

  4. Review of Fricke gel dosimeters

    The innovation of adding a gel matrix to the traditional Fricke dosimeter to stabilize geometric information established the field of gel dosimetry for radiation therapy. A discussion of Fricke gels provides an overview of the issues that determine the dose response of all gel dosimeters in general. In this paper we review some of the features of Fricke systems to illustrate these issues and, in addition, to motivate renewed clinical interest in Fricke gels

  5. Design of Autonomous Gel Actuators

    Shuji Hashimoto; Shingo Maeda; Yusuke Hara; Satoshi Nakamaru

    2011-01-01

    In this paper, we introduce autonomous gel actuators driven by chemical energy. The polymer gels prepared here have cyclic chemical reaction networks. With a cyclic reaction, the polymer gels generate periodical motion. The periodic motion of the gel is produced by the chemical energy of the oscillatory Belouzov-Zhabotinsky (BZ) reaction. We have succeeded in making synthetic polymer gel move autonomously like a living organism. This experimental fact represents the great possibility of the c...

  6. Design of Autonomous Gel Actuators

    Shuji Hashimoto

    2011-01-01

    Full Text Available In this paper, we introduce autonomous gel actuators driven by chemical energy. The polymer gels prepared here have cyclic chemical reaction networks. With a cyclic reaction, the polymer gels generate periodical motion. The periodic motion of the gel is produced by the chemical energy of the oscillatory Belouzov-Zhabotinsky (BZ reaction. We have succeeded in making synthetic polymer gel move autonomously like a living organism. This experimental fact represents the great possibility of the chemical robot.

  7. Ovine lentivirus is aetiologically associated with chronic respiratory disease of sheep on the Laikipia Plateau in Kenya.

    Rwambo, P M; Brodie, S J; DeMartini, J C

    2001-12-01

    A study was undertaken to investigate the occurrence of ovine lentivirus (OvLV) infection in sheep with chronic respiratory disease on the Laikipia Plateau, Kenya. All seven Merino crossbred sheep with chronic dyspnoea and emaciation examined for gross and microscopic lesions had lymphoid interstitial pneumonia (LIP), and one also had pulmonary abscesses. Two of the sheep with LIP also had lesions of ovine pulmonary carcinoma (OPC, jaagsiekte). Using in situ hybridization, OvLV DNA localized to a high proportion of pulmonary macrophages in lungs with lesions of LIP. Lung tissue samples from six of these sheep were positive for a syncytium-inducing virus in cultures of lamb testis cells. Thin-section electron microscopy of infected cells showed virions with morphogenesis typical of lentiviruses. In a western blotting assay, monoclonal antibodies to the OvLV capsid (CA, p27) and matrix (MA, p15) proteins of a North American OvLV isolate reacted with similar-sized bands of the virus, and serum from six of the sheep were reactive with CA from the Kenyan viral isolate. Using an OvLV agar gel immunodiffusion (AGID) test, all seven sheep were positive for serum antiviral antibody, as were 29% of 63 clinically normal sheep from Laikipia District. However, when sera from the healthy sheep were tested in a western blot assay, only 52% had IgG reactive to the OvLV CA, indicating a high rate of false negative reactions with the AGID test. Serum samples from 87 Red Maasai or Dorper crossbred sheep from two farms in other parts of Kenya were OvLV seronegative by both the AGID test and the western blot assay. These results document the first identification of OvLV as a cause of chronic respiratory disease in sheep in Kenya and show a high rate of infection in sheep flocks, with a high prevalence of chronic respiratory disease. PMID:11770202

  8. Gel-silica science

    Sol-gel techniques can be used to produce two new types of optical silicas, termed Type V for the full density material and Type VI for the optically transparent porous material. This paper summarizes the processing differences between these six types of commercial silicas. The primary emphasis of this paper is to discuss the scientific basis for the processing of Types V and VI optical silica. First, however, the use of sol-gel processing of other systems will be briefly reviewed. The controlled hydrolysis of alkoxides has also been used to produce submicrometer TiO2, doped TiO2 (17), ZrO2 (18), doped ZrO2 (18), doped SiO2 (19), SrTiO3 (20), and corderite (20) powders. Emulsions have been employed to produce spherical powders of mixed cation oxides, such as yttrium aluminum garnets (YAG) and many other systems (20). Sol-gel powder processes have also been applied to fissile elements (21) where spray form sols UO2, and rigid gel spheres of UO-PuO2 are formed during passage through a column of heated liquid. Both crystalline and vitreous ceramic fibers have been prepared using the sol-gel method. Compositions include TiO2-SiO2 and ZrO2-SiO2 glass fibers (22), high purity SiO2 waveguide fibers (23), Al2O3, ZrO2, ThO2, MgO, TiO2, ZrSiO4, 3AlO3-2SiO2 fibers (24). Sol-gel derived alumina grains are important commercial products (25)

  9. Linear electrochemical gel actuators

    Goswami, Shailesh; McAdam, C. John; Hanton, Lyall R.; Moratti, Stephen C.

    2012-04-01

    By using electroactive monomers it is possible to produce gels that respond to oxidation or reduction by swelling and deswelling in the presence of solvent. By the inclusion of an appropriate biasing element such as a spring, it is possible to produce linear, reversible actuation. The process can be driven electrochemically in a standard cell, with driving voltages under +/- 1 V. For many systems, the intrinsic conductivity of the gel, leading to poor or no performance. This can be overcome by blending conductive carbon nanotubes at 1% concentration, which give reasonable conductivity without affecting mechanical performance. Extensions of up to 40% are possible, against an external pressure of 30 kPa. The process is slow, taking up to 160 minutes per cycle due to slow ionic diffusion. The electrochemical cell can be cycled many times without degradation.

  10. MAGIC Gel Dosimetry

    Mifflin, Rachel; Shahnazi, Kambiz; Jesseph, Rick

    2008-10-01

    Proton therapy has proven a very successful tool in treating certain tumors, but a three dimensional view of this fact has not yet been clearly demonstrated. In this experiment we have used MAGIC (Methacrylic and Ascorbic Acid in Gelatin Initiated by Copper) gel to represent brain tissue and gone through normal treatment planning for an Acoustic Neuroma to show the three dimensional dose distributions associated with such a tumor.

  11. The Gel Generator option

    The development of a national policy for guaranteeing an ample supply of 99mTc to nuclear medicine, involves issues which go beyond the means by which radioactivation is achieved. Indeed, in such an exercise the pragmatic dictates of business and the sensitivities of politics must also be taken into account. Furthermore where a preference towards the nuclear reactor or the potential of cyclotrons is being questioned, the debate is incomplete if the only options that are considered are the fission-based 99Mo generator versus the direct cyclotron production of 99mTc. There is a third option (also neutron γ-based), an alternative to the fission 99Mo generator, which ought not be overlooked. The application of low specific activity (n,γ) 99Mo to a new type of generator, the Gel Generator, has been the focus of much research, particularly in Australia and more recently in China. After the initial concept had been established in the laboratory, the Australian researchers then undertook a comprehensive program of tests on the Gel Generator to assess its potential, either in the clinical laboratory or the centralised radiopharmacy, for supplying 99mTc suitable for nuclear medicine. The outcome of this program was a clear indication that the Gel Generator innovation had the capability to provide both technical and economic advantages to the nuclear medicine industry. These advantages are described. Since that time the Gel Generator has been selected for routine use in China where it now satisfies more than 30% of the 99mTc demand. (author)

  12. Aprotic gel polymer electrolytes

    Vondrák, Jiří; Sedlaříková, M.; Krejza, O.

    Brno : University of Technology Brno, 2008, s. 71-72. ISBN 978-80-214-3659-6. [International Conference Advanced Batteries and Accumulators /9./. Brno (CZ), 29.06.2008-03.07.2008] R&D Projects: GA ČR(CZ) GA104/06/1471; GA AV ČR(CZ) KJB208130604 Institutional research plan: CEZ:AV0Z40320502 Keywords : gel polymer electrolytes Subject RIV: CA - Inorganic Chemistry

  13. Staining Proteins in Gels

    Gallagher, Sean; Chakavarti, Deb

    2008-01-01

    Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. This unit describes protocols for detecting proteins by four popular methods. Coomassie blue staining is an easy and rapid method. Silver staining, while more time consuming, is considerably more sensitive and can thus be used to detect smaller amounts of protein. Fluorescent staining is a popular alternative to traditional staining procedures, mainly because it is more sensitive th...

  14. Seroepidemiology of Paracoccidioides brasiliensis infection in horses from Rio Grande do Sul, Brazil.

    Albano, Ana Paula Neuschrank; Klafke, Gabriel Baracy; Brandolt, Tchana Martinez; Da Hora, Vanusa Pousada; Nogueira, Carlos Eduardo Wayne; Xavier, Melissa Orzechowski; Meireles, Mário Carlos Araújo

    2015-06-01

    Paracoccidioides brasiliensis is the etiological agent of the major systemic mycosis in Brazil, called paracoccidioidomycosis. Although the Rio Grande do Sul is considered an endemic area of the disease, there are few studies on the ecology of P. brasiliensis in the state. Therefore, this study aimed to evaluate the infection of P. brasiliensis in horses from the mesoregion of Southwest Riograndense, using these animals as sentinels. Serological techniques, such as double immunodiffusion in agar gel (AGID) and indirect ELISA, were performed to detect the anti-gp43 P. brasiliensis antibody in horses from five different farms in the region of Bagé, RS, Brazil. Serology was performed in 200 Pure Blood English horses up to two years of age that were born and raised exclusively at the farms. Of these horses, 12% had anti-gp43 antibodies according to the ELISA results, with rates ranging from 0 to 30% according to the farm of origin (p < 0.001). Based on the immunodiffusion results, all equine serum samples were negative. These results indicate the presence of the fungus P. brasiliensis in the middle region of the southwestern state of Rio Grande do Sul, Brazil. PMID:26273267

  15. Seroepidemiology of Paracoccidioides brasiliensis infection in horses from Rio Grande do Sul, Brazil

    Ana Paula Neuschrank Albano

    2015-06-01

    Full Text Available Paracoccidioides brasiliensis is the etiological agent of the major systemic mycosis in Brazil, called paracoccidioidomycosis. Although the Rio Grande do Sul is considered an endemic area of the disease, there are few studies on the ecology of P. brasiliensis in the state. Therefore, this study aimed to evaluate the infection of P. brasiliensis in horses from the mesoregion of Southwest Riograndense, using these animals as sentinels. Serological techniques, such as double immunodiffusion in agar gel (AGID and indirect ELISA, were performed to detect the anti-gp43 P. brasiliensis antibody in horses from five different farms in the region of Bagé, RS, Brazil. Serology was performed in 200 Pure Blood English horses up to two years of age that were born and raised exclusively at the farms. Of these horses, 12% had anti-gp43 antibodies according to the ELISA results, with rates ranging from 0 to 30% according to the farm of origin (p < 0.001. Based on the immunodiffusion results, all equine serum samples were negative. These results indicate the presence of the fungus P. brasiliensis in the middle region of the southwestern state of Rio Grande do Sul, Brazil.

  16. Radiotherapy gel dosimetry

    shapes and sizes while sparing normal tissue. The situation is further complicated if the normal tissues are critical organs or are particularly sensitive to radiation. Radiotherapy techniques employed to obtain a closer conformation of the dose distribution to the tumour volume are referred to as conformal radiotherapy techniques. The clinical implementation of conformal therapy has been delayed by limitations in the verification of conformal dose distributions calculated by treatment planning systems prior to the irradiation of the patient and the verification of complex treatments during its delivery to the patient. There are several aspects of conformal therapy that complicate dose verification. To achieve the dose distributions conforming to complex 3D volumes, high dose gradients arise in the treatment volume. Further, overdose or underdose regions can exist when separate radiation fields are used to deliver additional radiation. These aspects require that practical dose measurement (dosimetry) techniques be able to integrate dose over time and easily measure dose distributions in 3D with high spatial resolution. Traditional dosimeters, such as ion chambers, thermoluminescent dosimeters and radiographic film do not fulfil these requirements. Novel gel dosimetry techniques are being developed in which dose distributions can potentially be determined in vitro in 3D using anthropomorphic phantoms to simulate a clinically irradiated situation. As long ago as the 1950's, radiation-induced colour change in dyes was used to investigate radiation doses in gels. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured using magnetic resonance imaging (MRI). In Fricke gels, Fe2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin, agarose or PVA matrix. Radiation-induced changes in the dosimeters are considered to

  17. Purification of Titania Gels

    Matějová, Lenka; Cajthaml, Tomáš; Klusoň, P.; Benada, Oldřich; Matěj, Z.; Šolcová, Olga

    Bratislava : Slovak Society of Chemical Engineering, 2008 - (Markoš, J.), s. 166 ISBN 978-80-227-2903-1. [35th International Conference of Slovak Society of Chemical Engineering. Tatranské Matliare (SK), 26.05.2008-30.05.2008] R&D Projects: GA AV ČR KAN400720701; GA AV ČR IAA4072404 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z50200510 Keywords : sol-gel * TiO2 powder * supercritic fluid extraction Subject RIV: CF - Physical ; Theoretical Chemistry

  18. Capillary fracture of soft gels

    Bostwick, Joshua B.; Daniels, Karen E.

    2013-01-01

    A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact-line in a starburst pattern. In this paper, we characterize i) the initiation process in which the number of arms in the starburst is controlled by the ratio of surface tension contrast to the gel's elastic modulus and ii) the propagation dynamics showing that once fractures are initiated they propaga...

  19. THE PROPERTIES OF CARRAGEENAN GELS

    Grubnik I.M., Gladukh Ye.V., Chernyaev S.V.

    2012-01-01

    The article presents the results of studies on the functional properties of carrageenan, depending on the concentration of sodium chloride and xanthan in gels. It is established that the main factors in the syneresis of carrageenan gels are its concentration, the presence of ions and gums in solution. If using sodium chloride there is a change in the structure of mesh of the resulting gel, which leads to an increase in syneresis.

  20. THE PROPERTIES OF CARRAGEENAN GELS

    Grubnik I.M., Gladukh Ye.V., Chernyaev S.V.

    2012-04-01

    Full Text Available The article presents the results of studies on the functional properties of carrageenan, depending on the concentration of sodium chloride and xanthan in gels. It is established that the main factors in the syneresis of carrageenan gels are its concentration, the presence of ions and gums in solution. If using sodium chloride there is a change in the structure of mesh of the resulting gel, which leads to an increase in syneresis.

  1. Colloidal thermoresponsive gel forming hybrids.

    Liu, Ruixue; Tirelli, Nicola; Cellesi, Francesco; Saunders, Brian R

    2010-09-15

    Colloidal hybrids comprise organic and inorganic components and are attracting considerable attention in the literature. Recently, we reported hybrid anisotropic microsheets that formed thermoresponsive gels in polymer solutions [Liu et al., Langmuir, 25, 490, 2009]. Here, we investigate the composition and properties of these hybrid colloids themselves in detail for the first time. Three different cationic PNIPAm (N-isopropylacrylamide) graft copolymers and two inorganic nanoparticle types (laponite and Ludox silica) were used to prepare a range of hybrids. Anisotropic microsheets only formed when laponite particles were added to the copolymer implying directed self-assembly. Aqueous dispersions of the microsheets spontaneously formed gels at room temperature and these gels were thermoresponsive. They represent a new class of gel forming colloid and are termed thermoresponsive gel forming hybrids. The compositions of the hybrids were determined from thermogravimetric analysis and those that gave gel forming behaviour identified. Variable-temperature rheology experiments showed that the elasticity of the gels increased linearly with temperature. The reversibility of the thermally-triggered changes in gel elasticity was investigated. The concentration dependence of the rheology data was well described by elastic percolation scaling theory and the data could be collapsed onto a master curve. The concentration exponent for the elastic modulus was 2.5. The strong attractive interactions that exist between the dispersed gel forming hybrids was demonstrated by the formation of stable thermoresponsive hybrid hydrogels through casting of hybrid dispersions. PMID:20561633

  2. Detection of serum antibodies to ovine progressive pneumonia virus in sheep by using a caprine arthritis-encephalitis virus competitive-inhibition enzyme-linked immunosorbent assay.

    Herrmann, Lynn M; Cheevers, William P; Marshall, Katherine L; McGuire, Travis C; Hutton, Melinda M; Lewis, Gregory S; Knowles, Donald P

    2003-09-01

    A competitive-inhibition enzyme-linked immunosorbent assay (cELISA) for detection of antibodies to the surface envelope (SU) of caprine arthritis-encephalitis virus (CAEV) was recently reported (L. M. Herrmann, W. P. Cheevers, T. C. McGuire, D. Scott Adams, M. M. Hutton, W. G. Gavin, and D. P. Knowles, Clin. Diagn. Lab. Immunol. 10:267-271, 2003). The cELISA utilizes CAEV-63 SU captured on microtiter plates using the monoclonal antibody (MAb) F7-299 and measures competitive displacement of binding of the anti-CAEV MAb GPB 74A by goat serum. The present study evaluated the CAEV cELISA for detection of antibodies to ovine progressive pneumonia virus (OPPV) in sheep. Three hundred thirty-two sera were randomly selected from 21,373 sheep sera collected throughout the United States to determine the sensitivity and specificity of cELISA and agar gel immunodiffusion (AGID) based on immunoprecipitation (IP) of [35S]methionine-labeled OPPV antigens as a standard of comparison. A positive cELISA test was defined as >20.9 percent inhibition (% I) of MAb 74A binding based on two standard deviations above the mean % I of 191 IP-negative sheep sera. At this cutoff, there were 2 of 141 false-negative sera (98.6% sensitivity) and 6 of 191 false-positive sera (96.9% specificity). Sensitivity and specificity values for IP-monitored AGID were comparable to those for cELISA for 314 of 332 sera with unambiguous AGID results. Concordant results by cELISA and IP resolved 16 of the 18 sera that were indeterminate by AGID. Additional studies evaluated cELISA by using 539 sera from a single OPPV-positive flock. Based on IP of 36 of these sera, there was one false-negative by cELISA among 21 IP-positive sera (95.5% sensitivity) and 0 of 15 false-positives (100% specificity). We conclude that the CAEV cELISA can be applied to detection of OPPV antibodies in sheep with high sensitivity and specificity. PMID:12965917

  3. Evaluation of standard reagents for radial-immunodiffusion assays. In vitro control of rabies vaccines Avaliação de reativos padrões para provas de Imunodifusão Radial. Controle in vitro de vacinas antirrábicas

    MICELI Graciela S.; Jorge TORROBA; TORRES Walter; ESTEVES MADERO Jorge; Ana Maria DÍAZ

    2000-01-01

    The RID assay is one of the in vitro methods used for in-process control in the production of rabies vaccines for veterinary use. It has been shown to be very useful for determining antigen concentration in the final bulk product. The work presented in this paper, including the production and standardization of candidate standard reagents for use in the Radial Immunodiffusion Assay (RID) was carried out at the Pan American Institute for Food Protection and Zoonoses (INPPAZ/PAHO/WHO). The stud...

  4. Antimicrobial Graft Copolymer Gels.

    Harvey, Amanda C; Madsen, Jeppe; Douglas, C W Ian; MacNeil, Sheila; Armes, Steven P

    2016-08-01

    In view of the growing worldwide rise in microbial resistance, there is considerable interest in designing new antimicrobial copolymers. The aim of the current study was to investigate the relationship between antimicrobial activity and copolymer composition/architecture to gain a better understanding of their mechanism of action. Specifically, the antibacterial activity of several copolymers based on 2-(methacryloyloxy)ethyl phosphorylcholine [MPC] and 2-hydroxypropyl methacrylate (HPMA) toward Staphylococcus aureus was examined. Both block and graft copolymers were synthesized using either atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization and characterized via (1)H NMR, gel permeation chromatography, rheology, and surface tensiometry. Antimicrobial activity was assessed using a range of well-known assays, including direct contact, live/dead staining, and the release of lactate dehydrogenase (LDH), while transmission electron microscopy was used to study the morphology of the bacteria before and after the addition of various copolymers. As expected, PMPC homopolymer was biocompatible but possessed no discernible antimicrobial activity. PMPC-based graft copolymers comprising PHPMA side chains (i.e. PMPC-g-PHPMA) significantly reduced both bacterial growth and viability. In contrast, a PMPC-PHPMA diblock copolymer comprising a PMPC stabilizer block and a hydrophobic core-forming PHPMA block did not exhibit any antimicrobial activity, although it did form a biocompatible worm gel. Surface tensiometry studies and LDH release assays suggest that the PMPC-g-PHPMA graft copolymer exhibits surfactant-like activity. Thus, the observed antimicrobial activity is likely to be the result of the weakly hydrophobic PHPMA chains penetrating (and hence rupturing) the bacterial membrane. PMID:27409712

  5. Rheology and structure of milk protein gels

    Vliet, van T.; Lakemond, C.M.M.; Visschers, R.W.

    2004-01-01

    Recent studies on gel formation and rheology of milk gels are reviewed. A distinction is made between gels formed by aggregated casein, gels of `pure` whey proteins and gels in which both casein and whey proteins contribute to their properties. For casein' whey protein mixtures, it has been shown th

  6. Relación entre la prueba intradermica de histoplasmina y los niveles de anticuerpos detectables por ELISA e immunodifusion Relationship between histoplasmin skin test and Histoplasma capsulatum antibody levels detected by ELISA and immunodiffusion tests

    Carlos M. Fernandez-Andreu

    1994-02-01

    Full Text Available Se realizó un estudio prospectivo en 40 trabajadores de una granja avícola (grupo 1 considerados con riesgo de exposición a Histoplasma capsulatum, agente etiológico de la histoplasmosis, y en 16 individuos sin riesgo profesional de exposición a dicho agente (grupo 2. En ambos grupos se aplicó la prueba intradérmica de histoplasmina y se obtuvo el suero antes de su aplicación y a los 30 y 180 días después de realizada dicha prueba. Se determinó el nivel de anticuerpos anti-H. capsulatum mediante las técnicas de ELISA e inmunodifusión doble. En los dos grupos de población estudiados la aplicación intradérmica de histoplasmina, aún en los casos en que la respuesta fue positiva, no constituyó un estímulo antigénico suficiente para provocar un aumento en los niveles de anticuerpos anti-H. capsulation detectables por las técnicas serológicas empleadas. Los resultados obtenidos contribuyen a la mejor interpretación de la prueba de ELISA en el diagnóstico de la histoplasmosis.A prospective study was carried out in two groups of individuals: a group 1 (n=40 included workers from a poultry farm, with potencial occupational risk of exposure to Histoplasma capsulatum, ethiologic agent of histoplasmosis, and a group 2 (n=16, persons without occupational risk of exposure to the agent. Histoplasmin skin test was performed in both groups, and three sera were obtained from each individual: 1 before skin test was done, 2 30 days after, and 3 180 days after it. In both groups the histoplasmin skin test, even when the test was positive, was not a sufficient antigenic booster to provoque an increase in the H. capsulatum antibody levels capable to be detected by the Serologic tests used (ELISA and Double Immunodiffusion. These results contribute to improve the interpretation of ELISA test values in the diagnosis of histoplasmosis.

  7. Nanocrystal/sol-gel nanocomposites

    Petruska, Melissa A.; Klimov, Victor L.

    2012-06-12

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites

  8. Nanocrystal/sol-gel nanocomposites

    Petruska, Melissa A.; Klimov, Victor L.

    2007-06-05

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites.

  9. Sucrose release from polysaccharide gels.

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed. PMID:26952168

  10. BLUETONGUE VIRUS ANTIBODIES DETECTIONS IN SHEEP FROM ARAÇATUBA REGION –SAO PAULO, BRAZIL DETECÇÃO DE ANTICORPOS CONTRA O VÍRUS DA LÍNGUA AZUL EM OVINOS NA REGIÃO DE ARAÇATUBA – SÃO PAULO, BRASIL

    Adriana Hellmeister de Campos Nogueira

    2009-12-01

    Full Text Available

    Bluetongue (BT is an infectious, insect-born viral disease of ruminants. The causative agent of BT is bluetongue virus (BTV that belongs to the family Reoviridae genus Orbivirus. Insect vectors in the genus Culicoides transmit this virus. BT affects domestic and wild ruminants, however small ruminants are considered the most affected specie. The aim of the study was to detect antibodies against BTV in commercial sheep farms, of the Northeastern region of Sao Paulo State, Brazil. A total of 1002 sera samples collected from adult sheep (above 1 year-old, comprising a total of 31 farms, were screened for the presence of BTV antibodies, by agar gel immunodiffusion test (AGID and ELISA-CFS (Enzyme Linked Immunosorbent Assay – competitive solid phase, both produced by Pan American Center of FMDV. From a total of 1002 samples, 651 (65% were positive by AGID and 742 (74.1%, were positive by ELISA-CFS. These results suggest that the BTV is widespread among farms, probably causing subclinical infections.

    KEY WORDS: AGID, bluetongue virus, ELISA-CFS, seroepidemiological survey.

    A língua azul é uma doença viral, cujo agente etiológico pertence à família Reoviridae, gênero Orbivirus, transmitida por um vetor (artrópode hematófago, do gênero Culicoides. Os animais acometidos são ruminantes domésticos e selvagens, porém os pequenos ruminantes são os mais afetados. O estudo teve como objetivo detectar a presença de anticorpos para língua azul em ovinos da região de Araçatuba, por possuir um rebanho expressivo e condições climáticas favoráveis à multiplicação de insetos. Foram analisadas 1.002 amostras de soros ovinos, provenientes de 31 cabanhas, pelas provas de imunodifusão dupla em gel de ágar (AGID e ELISA (Enzyme Linked immunosorbent Assay de competição da fase sólida (ELISA CFS, provenientes do Centro Panamericano de Febre Aftosa. Desses soros, 651 (65% foram

  11. Evaluación de la eficacia de la prueba de inmunodifusión en gel agar para la detección de anticuerpos contra el virus de la leucosis enzootica bovina Assessment of the Efficacy of the Agar Gel Immunodiffusion Test for the Detection of Antibodies Against the Enzootic Bovine Leukosis Virus

    Zoraida Nava; César Obando; Magaly Bracamonte; Aurico Sousa; Mayra Hidalgo

    2012-01-01

    contra el virus de la leucosis enzoótica bovina (VLEB), comparándola con el ensayo inmunoenzimático (ELISA). Se procesaron 360 muestras de suero bovino para ambas pruebas, siguiendo las indicaciones del fabricante. El grado de concordancia (GC), valores predictivos (VP) y razones de verosimilitud (RV) fueron determinados y analizados. El GC entre ambas pruebas resultó ser del 86,4%, con un coeficiente Kappa (K) = 0,7. La IDGA detectó una significativa (P

  12. Chemical Gel for Surface Decontamination

    Many chemical decontamination processes operate by immersing components in aggressive chemical solutions. In these applications chemical decontamination technique produce large amounts of radioactive liquid waste. Therefore it is necessary to develop processes using chemical gels instead of chemical solutions, to avoid the well-known disadvantages of chemical decontamination techniques while retaining their high efficiency. Chemical gels decontamination process consists of applying the gel by spraying it onto the surface of large area components (floors, walls, etc) to be decontaminated. The gel adheres to any vertical or complex surface due to their thixotropic properties and operates by dissolving the radioactive deposit, along with a thin layer of the gel support, so that the radioactivity trapped at the surface can be removed. Important aspects of the gels are that small quantities can be used and they show thixitropic properties : liquid during spraying, and solid when stationary, allowing for strong adherence to surfaces. This work investigates the decontamination behaviors of organic-based chemical gel for SS 304 metallic surfaces contaminated with radioactive materials

  13. sol-gel

    Humberto A. Monreal

    2005-01-01

    Full Text Available En este trabajo sintetizamos nanocilindros de dióxido de titanio de 30 a 400 nm por medio de ADN del plásmido pBR322 de 4,362 pares de bases y el uso de isopropóxido de titanio como precursor por medio del proceso sol-gel. Los geles resultantes fueron calcinados y los polvos caracterizados por medio de Microscopio Electrónico de Barrido (MEB, Espectroscopía de Energía Dispersiva, Microscopio Electrónico de Transmisión (MET y Difracción de Rayos X. Los resultados muestran que la síntesis in vitro de nanorods en presencia de ADN, puede ser activada. Muchas otras moléculas sintéticas pueden producirse por medio del uso de sistemas orgánicos, es así como reportamos la síntesis de híbridos hechos de ácidos nucleicos en materiales inorgánicos que pueden tener diversas aplicaciones en sistemas catalíticos, biomateriales y materiales nanoestructurados.

  14. Denaturing gradient gel electrophoresis

    It is worthwhile considering that only some 30 species make up the bulk of the bacterial population in human faeces at any one time based on the classical cultivation-based approach. The situation in the rumen is similar. Thus, it is practical to focus on specific groups of interest within the complex community. These may be the predominant or the most active species, specific physiological groups or readily identifiable (genetic) clusters of phylogenetically related organisms. Several 16S rDNA fingerprinting techniques can be invaluable for selecting and monitoring sequences or phylogenetic groups of interest and are described below. Over the past few decades, considerable attention was focussed on the identification of pure cultures of microbes on the basis of genetic polymorphisms of DNA encoding rRNA such as ribotyping, amplified fragment length polymorphism and randomly amplified polymorphic DNA. However, many of these methods require prior cultivation and are less suitable for use in analysis of complex mixed populations although important in describing cultivated microbial diversity in molecular terms. Much less attention was given to molecular characterization of complex communities. In particular, research into diversity and community structure over time has been revolutionized by the advent of molecular fingerprinting techniques for complex communities. Denaturing or temperature gradient gel electrophoresis (DGGE/TGGE) methods have been successfully applied to the analysis of human, pig, cattle, dog and rodent intestinal populations

  15. Field inversion gel electrophoresis in denaturing polyacrylamide gels.

    Heller, C.; Beck, S

    1992-01-01

    The velocities of single stranded DNA molecules in denaturing polyacrylamide gels during symmetric and asymmetric field inversion were measured at different pulse times and gel concentrations. Under the conditions chosen in our study, pulse times as short as a few milliseconds lead to a retardation of DNA molecules larger than 400 bases. We found that a field inversion with an electric field in the forward direction of about double the strength of that applied in the backward direction is a g...

  16. Silica reinforced triblock copolymer gels

    Theunissen, E.; Overbergh, N.; Reynaers, H.;

    2004-01-01

    scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from a...... viscoclastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel. (C) 2004 Elsevier Ltd. All rights reserved.......The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order to...

  17. Raft Instability of Biopolymer Gels

    Borukhov, I.; Bruinsma, R.F.

    2002-01-01

    Following recent X-ray diffraction experiments by Wong, Li, and Safinya on biopolymer gels, we apply Onsager excluded volume theory to a nematic mixture of rigid rods and strong ``$\\pi/2$'' cross-linkers obtaining a long-ranged, highly anisotropic depletion attraction between the linkers. This attraction leads to breakdown of the percolation theory for this class of gels, to breakdown of Onsager's second-order virial method, and to formation of heterogeneities in the form of raft-like ribbons.

  18. Topical Review: Polymer gel dosimetry

    Baldock, C; De Deene, Y; Doran, S.; Ibbott, G; Jirasek, A.; Lepage, M.; McAuley, K B; Oldham, M; Schreiner, L J

    2010-01-01

    Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose ...

  19. Alternative imaging modalities for polymer gel dosimetry

    Jirasek, Andrew, E-mail: jirasek@uvic.c [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6 (Canada)

    2010-11-01

    This review summarizes recent work in the area of imaging polymer gel dosimeters using x-ray CT imaging, ultrasound, and radiation-induced changes in gel mechanical properties. In addition, recent work in the area of Raman tomographic imaging of canine bone, in conjunction with past efforts in Raman imaging of polymer gel dosimeters, raises new possibilities for new polymer gel imaging techniques.

  20. Thixotropic gel for vadose zone remediation

    Riha, Brian D.; Looney, Brian B.

    2015-10-27

    A thixotropic gel suitable for use in subsurface bioremediation is provided along with a process of using the gel. The thixotropic gel provides a non-migrating injectable substrate that can provide below ground barrier properties. In addition, the gel components provide for a favorable environment in which certain contaminants are preferentially sequestered in the gel and subsequently remediated by either indigenous or introduced microorganisms.

  1. Thixotropic gel for vadose zone remediation

    Rhia, Brian D.

    2011-03-01

    A thixotropic gel suitable for use in subsurface bioremediation is provided along with a process of using the gel. The thixotropic gel provides a non-migrating injectable substrate that can provide below ground barrier properties. In addition, the gel components provide for a favorable environment in which certain contaminants are preferentially sequestered in the gel and subsequently remediated by either indigenous or introduced microorganisms.

  2. Surface grafted chitosan gels. Part II. Gel formation and characterization

    Liu, Chao; Thormann, Esben; Claesson, Per M.;

    2014-01-01

    Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After...... cross-linking the chitosan present in the polyelectrolyte multilayer, poly(acrylic acid) is partly removed by exposing the multilayer structure to a concentrated carbonate buffer solution at a high pH, leaving a surface-grafted cross-linked gel. Chemical cross-linking enhances the gel stability against...... detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross...

  3. 3-dimensional polymer gel dosimetry

    Recently developed techniques in conformal radiotherapy demand special properties of radiation dosimeters. Polymer gel dosimeter evaluated by nuclear magnetic resonance (NMR) is promising tool which can be used for measuring rather complicated 3-dimensional dose distributions with required precision of ± 5 %. This system is based on radiation-induced polymerisation and cross-linking of acrylic monomers which are uniformly dispersed in aqueous gel. The formation of cross-linked polymers in the irradiated regions of the gel increases the NMR relaxation rates of neighbouring water protons. BANG-2 type polymer gel was prepared. The composition of gel dosimeter was as follows: 3 % N,N'-methylene-bisacrylamide, 3 % acrylic acid, 1 % sodium hydroxide, 5 % gelatine, and 88 % water, where all percentages are by weight. The dosimeters in glass vessels were homogeneously irradiated by 60Co gamma photons in a Gammacell 220 unit and by 4 MV, 6 MV and 18 MV X ray photons on Varian Clinac 600C and 2100 C linear accelerators by doses in the range of 0-50 Gy. Evaluation of dosimeters was performed on Siemens EXPERT 1 T and Siemens VISION 1,5 T scanners. Multi-echo CPMG sequence with 16 echoes was used for the evaluation of T2-relaxation times in irradiated gel dosimeters. The dependence of 1/T2 response of dosimeters was studied on following factors: absorbed dose, energy of applied radiation, temperature during NMR evaluation, time since irradiation to NMR evaluation and strength of the magnetic field. An exponential dependence of 1/T2 response on absorbed dose in the range of 0-50 Gy was observed, in the range 0-10 Gy the data could be fitted by a linear function. There was observed no dependence of 1/T2 response on: energy (for three different photon energies used in this study), strength of magnetic field of NMR scanner, time from irradiation of the dosimeters to NMR evaluation. Increase of gel dosimeter 1/T2 response with the decrease of the temperature during NMR evaluation

  4. Yield stress determination of a physical gel

    Hvidt, Søren

    2013-01-01

    Pluronic F127 solutions form gels in water with high elastic moduli. Pluronic gels can, however, only withstand small deformations and stresses. Different steady shear and oscillatory methods traditionally used to determine yield stress values are compared. The results show that the yield stresse...... values of these gels depend on test type and measurement time, and no absolute yield stress value can be determined for these physical gels.......Pluronic F127 solutions form gels in water with high elastic moduli. Pluronic gels can, however, only withstand small deformations and stresses. Different steady shear and oscillatory methods traditionally used to determine yield stress values are compared. The results show that the yield stresses...

  5. Screening effect on nanostructure of charged gel

    Sugiyama, M; Annaka, M; Hino, M;

    2004-01-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions. The...... dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content. (C) 2004 Elsevier B. V. All rights...

  6. Persistence of immunity in commercial egg-laying hens following vaccination with a killed H6N2 avian influenza vaccine.

    Cardona, Carol J; Charlton, Bruce R; Woolcock, Peter R

    2006-09-01

    The California poultry industry experienced an outbreak of H6N2 avian influenza beginning in February 2000. The initial infections were detected in three commercial egg-laying flocks and a single noncommercial backyard flock but later spread to new premises. The vaccination of pullet flocks with a commercially prepared, killed autogenous vaccine prior to their placements on farms with infected or previously infected flocks was used as a part of the eradication programs for some multiage, commercial egg production farms. The purpose of this study was to follow three vaccinated flocks on two commercial farms to track the immune responses to vaccination. The antibody-mediated responses of the three flocks followed in this study were markedly different. One flock achieved 100% seroconversion at 12.5 wk of age, but by 32 wk of age, all of the hens were seronegative by agar gel immunodiffusion (AGID). In contrast, at 32 wk of age, flocks from the other farm (flocks 2A and 2B) were 95% and 72% seropositive by AGID, respectively. Of the differences that were identified between the vaccination protocols on the two farms, the distinction that could explain the level of disparity between responses is the delivery of the second dose of vaccine with a bacterin on the first farm, which may have interfered with the persistence of immunity in this flock. Hens from flocks 2A and 2B were experimentally challenged at 25 wk of age with H6N2 avian influenza virus. Hens from flock 2A did not transmit virus to naive contact-exposed hens, but hens from flock 2B did. At 34 wk of age, hens from flock 2A were again challenged and naive contact-exposed hens were infected in this second trial. These challenge experiments served to demonstrate that despite detectable antibody responses in flocks 2A and 2B, the birds were protected from infection for less than 21 wk after the second vaccination. PMID:17039836

  7. 百色市马传染性贫血的综合防制%The comprehensive prevention of equine infectious anemia in Baise city

    蒙振亩; 陆春礼; 覃勇; 黄百花; 赵聪; 卢少坤

    2015-01-01

    In order to effectively prevent and control the prevalence of equine infectious anemia in Baise city, AGAR gel immunodiffusion (AGID) test, spotted an ELISA (DB), and immune strip rapid test (ICLF) were used to detect 9950 serum samples of equus . Two serum samples were detected positive, and the positive rate was 0.02% . The two positive horses were culled and harmless treated. The prevention and control of equine infectious anemia in Baise have reached standard by strengthening proper measures such as epidemiological investigation, inspection and quarantine, epidemic prevention supervision, disinfection,to drive out the blood-sucking insects, and so on. Analysis suggests that the successful experience to eliminate the equine infectious anemia is to take comprehensive prevention measures.%为有效防控马传染性贫血发生及流行,百色市采用琼脂凝胶免疫扩散试验(AGID)、斑点单抗ELISA(DB)、免疫试纸快速检测法(ICLF)等血清学检测方法,检测马属动物血清样品9950份,检出阳性2份,阳性率0.02%,对检出阳性的2匹马进行扑杀并作无害化处理.加强开展流行病学调查、检疫、防疫监督、消毒及驱灭吸血昆虫等防制措施,马传染性贫血防治工作达到了消灭标准.文章分析认为,采取综合防制措施是消灭马传染性贫血的成功经验.

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

    K. K. Sharma

    2015-04-01

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

  9. Capillary fracture of soft gels.

    Bostwick, Joshua B; Daniels, Karen E

    2013-10-01

    A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L[proportional]t(3/4). We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent. PMID:24229192

  10. Calculating Percent Gel For Process Control

    Webster, Charles Neal; Scott, Robert O.

    1988-01-01

    Reaction state of thermosetting resin tracked to assure desired properties. Rate of gel determined as function of temperature by measuring time to gel of part of graphite fabric impregnated with Hexcel R120 (or equivalent) phenolic resin.

  11. A method for labeling polyacrylamide gels

    sprotocols

    2015-01-01

    Have you ever struggled with the identification of your polyacrylamide gels after running a few of them at once? Here is a new method for labeling gels which is easy, free and does not interfere with your protein samples. You will be intrigued once you learn how you can add a label to your laboratory-made gels and will have no problem identifying your gels any more.

  12. Consolidation of Inorganic Precipitated Silica Gel

    Matthias Kind; Hussein Sahabi

    2011-01-01

    Colloidal gels are possible intermediates in the generation of highly porous particle systems. In the production process the gels are fragmented after their formation. These gel fragments compact to particles whose application-technological properties are determined by their size and porosity. In the case of precipitated silica gels, this consolidation process depends on temperature and pH, among other parameters. It is shown that these dependencies can be characterized by oedometer measureme...

  13. Hybrid Materials of Polymer Gels with Surfactants

    Hu Yan; Kaoru Tsujii

    2005-01-01

    @@ 1 Introduction Polymer gels have been extensively studied[1~17] since the discovery of volume phase-transition of a gel by Tanaka[1~5]. As a unique soft material, gels attract much attention and are tried to be applied for drug-delivery systgems[6], actuators or chemo-mechanical devices[7~9] and so on. In particular, controlled-release of small molecules from a gel is now a subject of special interest[10].

  14. Spring-loaded polymeric gel actuators

    Shahinpoor, M.

    1995-02-14

    Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications. 5 figs.

  15. Gel dosimetry for conformal radiotherapy

    With the continuum development of conformal radio therapies, aimed at delivering high dose to tumor tissue and low dose to the healthy tissue around, the necessities has appeared of suitable improvement of dosimetry techniques giving the possibility of obtaining dose images to be compared with diagnostic images. Also if wide software has been developed for calculating dose distributions in the fields of various radiotherapy units, experimental verifications are necessary, in particular in the case of complex geometries in conformal radiotherapy. Gel dosimetry is a promising method for imaging the absorbed dose in tissue-equivalent phantoms, with the possibility of 3D reconstruction of the spatial dose distribution, with milli metric resolution. Optical imaging of gel dosimeters, based on visible light absorbance analysis, has shown to be a reliable technique for achieving dose distributions. (Author)

  16. The Swelling of Olympic Gels

    Lang, Michael; Fischer, Jakob; Werner, Marco; Sommer, Jens-Uwe

    2014-03-01

    The swelling equilibrium of Olympic gels is studied by Monte Carlo Simulations. We observe that gels consisting of flexible cyclic molecules of a higher degree of polymerization N show a smaller equilibrium swelling degree Q ~N - 0 . 28φ0- 0 . 72 for the same monomer volume fraction φ0 at network preparation. This observation is explained by a disinterpenetration process of overlapping non-concatenated polymers upon swelling. In the limit of a sufficiently large number of concatenations per cyclic molecule we expect that the equilibrium degree of swelling becomes proportional to φ0- 1 / 2 independent of N. Our results challenge current textbook models for the equilibrium degree of swelling of entangled polymer networks. Now at: Bio Systems Analysis Group, Jena Centre for Bioinformatics (JCB) and Department for Mathematics and Computer Sciences, Friedrich Schiller University of Jena, 07743 Jena, Germany.

  17. The Gel Electrophoresis Markup Language (GelML) from the Proteomics Standards Initiative

    Gibson, Frank; Hoogland, Christine; Martinez-Bartolomé, Salvador; Medina-Aunon, J. Alberto; Albar, Juan Pablo; Babnigg, Gyorgy; Wipat, Anil; Hermjakob, Henning; Almeida, Jonas S; Stanislaus, Romesh; Paton, Norman W.; Jones, Andrew R.

    2010-01-01

    The Human Proteome Organisation’s Proteomics Standards Initiative (HUPO-PSI) has developed the GelML data exchange format for representing gel electrophoresis experiments performed in proteomics investigations. The format closely follows the reporting guidelines for gel electrophoresis, which are part of the Minimum Information About a Proteomics Experiment (MIAPE) set of modules. GelML supports the capture of metadata (such as experimental protocols) and data (such as gel images) resulting f...

  18. Electrophoresis of DNA in agarose gels, polyacrylamide gels and in free solution

    Stellwagen, Nancy C.

    2009-01-01

    This review describes the electrophoresis of curved and normal DNA molecules in agarose gels, polyacrylamide gels and in free solution. These studies were undertaken to clarify why curved DNA molecules migrate anomalously slowly in polyacrylamide gels but not in agarose gels. Two milestone papers are cited, in which Ferguson plots were used to estimate the effective pore size of agarose and polyacrylamide gels. Subsequent studies on the effect of the electric field on agarose and polyacrylami...

  19. Water equivalence of polymer gel dosimeters

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Zeff), electron density (ρe), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μen/ρ) and total stopping power (S/ρ)tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close (en/ρ for all polymer gels were in close agreement (tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

  20. Gel fire suppressants for controlling underground heating

    HU Sheng-gen; XUE Sheng

    2011-01-01

    One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines.CSIRO researchers have developed a number of polymer gels suitable for controlling heatings in coal mines.These gels were developed to meet strict selection criteria including easy preparation,no or low toxicity,controllable gelation time,adaptable to mine water chemistry,adjustable viscosity,relatively long gel life,thermally and chemically stable and low cost.The HPAM-Aluminum Citrate gel system was identified to be the most favourable gel system for fire suppression in underground coal mines.These gels can be applied to the areas undergoing coal heating or gas leakage at a controllable gelation time and impermeable gel barriers can be formed in the areas to block ingress of air.

  1. Consolidation of Inorganic Precipitated Silica Gel

    Matthias Kind

    2011-08-01

    Full Text Available Colloidal gels are possible intermediates in the generation of highly porous particle systems. In the production process the gels are fragmented after their formation. These gel fragments compact to particles whose application-technological properties are determined by their size and porosity. In the case of precipitated silica gels, this consolidation process depends on temperature and pH, among other parameters. It is shown that these dependencies can be characterized by oedometer measurements. Originally, the oedometer test (one-dimensional compression test stemmed from soil mechanics. It has proven to be an interesting novel examination method for gels. Quantitative data of the time-dependent shrinkage of gel samples can be obtained. The consolidation of the gels shows a characteristic dependence on the above parameters.

  2. Aspects of dosimetry using radiation sensitive gels

    The use of radiation sensitive gels for dosimetry measurements was first suggested in the 1950s. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. However, due to predominantly diffusion-related limitations, alternative polymer gel dosimeters were suggested. Clinical applications of these radiologically tissue equivalent gel dosimeters using magnetic resonance imaging (MRI) have subsequently been reported in the literature. In Fricke gels, Fe2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin or agarose hydrogel matrix. Radiation-induced changes in the dosimeters are considered to be either through direct absorption of ionising radiation or via intermediate water free radicals. Fe2+ ions are converted to Fe3+ ions with a corresponding change in paramagnetic properties that may be quantified using NMR relaxation measurements. In polymer gels, monomers are also dispersed in a gelatin or agarose hydrogel matrix. Monomers undergo a polymerisation reaction as a function of absorbed dose resulting in a three-dimensional polymer gel matrix. The radiation-induced formation of polymer influences NMR relaxation properties. The growth in polymer also results in other physical changes that may be used to quantify absorbed radiation dose. This thesis investigates various aspects of radiation dosimetry using radiation sensitive gels. Image processing software was developed to calculate NMR relaxation images of dosimetry gels. Measurements were undertaken to investigate the diffusion problem in Fricke gels. Radiological properties were theoretically modelled for both Fricke and polymer gels. A methodology was developed for the preparation of polymer gels. Vibrational spectroscopic studies were undertaken to investigate the underlying mechanism involved in the radiation-induced formation of polymer. MRI pulse

  3. PEMANFAATAN LIMBAH SEKAM PADI MENJADI SILIKA GEL

    Prima Astuti Handayani

    2014-12-01

    Full Text Available Sekam padi merupakan salah satu sumber penghasil silika terbesar, berpotensi sebagai bahan pembuatan silika gel. Abu sekam padi mengandung silika sebanyak 87%-97% berat kering. Sintesis silika gel dari abu sekam padi dilakukan dengan mereaksikan abu sekam padi menggunakan larutan NaOH 1N pada suhu 800C selama 1 jam dan dilanjutkan dengan penambahan larutan asam hingga pH=7. Gel yang dihasilkan selanjutnya didiamkan selama 18 jam kemudian dikeringkan pada suhu dikeringkan menggunakan oven pada suhu 800C hingga beratnya konstan. Hasil percobaan diperoleh bahwa silika gel dengan penambahan CH3COOH menghasilkan yield yang lebih besar dibandingkan penambahan HCl. Berdasarkan analisis FT-IR silika gel yang diperoleh memiliki gugus Si-O-Si dan gugus Si-OH. Silika gel dengan penambahan HCl memiliki surface area sebesar 65,558 m2/g, total pore volume 0,1935 cc/g, dan average pore size sebesar 59,0196 Å. Sedangkan silika gel dengan penambahan CH3COOH memiliki surface area sebesar 9,685 m2/g, total pore volume 0,02118 cc/g, dan average pore size sebesar 43,7357Å. Silika gel dengan penambahanCH3COOH memiliki kemampuan menyerap kelembaban udara yang lebih baik dibanding silika gel dengan penambahan HCl. Rice hull ash (RHA is one of the biggest source of silica, potential for sintesis silica gel. RHA contains silica as many as 87 % -97 %. Synthesis of silica gel from rice hull ash was done by reaction using NaOH solution at temperature 800C for 1 hour and followed by the addition of an acid solution until pH=7. The gel were rested with time aging 18 hour, and then dried using oven at temperature 800C until constant weigh. The results obtained that the silica gel with the addition of CH3COOH produce higher yields than the addition of HCl. Based on FT-IR analysis, silica gel has a group of silanol (Si-`OH and siloxan (Si-O-Si group. Silica gel with the addition of HCl has a surface area 65,558 m2/g, a total pore volume 0,1935 cc/g, and average pore size 59

  4. Metal-silica sol-gel materials

    Stiegman, Albert E. (Inventor)

    2002-01-01

    The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

  5. Chitosan: Gels and Interfacial Properties

    Julie Nilsen-Nygaard; Strand, Sabina P.; Kjell M. Vårum; Kurt I. Draget; Catherine T. Nordgård

    2015-01-01

    Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine) is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. T...

  6. Motility initiation in active gels

    Recho, Pierre; Truskinovsky, Lev

    2015-01-01

    Motility initiation in crawling cells requires a symmetry breaking mechanism which transforms a symmetric state into a polarized state. Experiments on keratocytes suggest that polarization is triggered by increased contractility of motor proteins. In this paper we argue that contraction can be responsible not only for the symmetry breaking transition but also for the incipient translocation of the segment of an active gel mimicking the crawling cell. Our model suggests that when the contractility increases sufficiently far beyond the motility initiation threshold, the cell can stop and re-symmetrizes. The proposed theory reproduces the motility initiation pattern in fish keratocytes and the behavior of keratocytes prior to cell division.

  7. Automated apparatus for producing gradient gels

    Anderson, N.L.

    1983-11-10

    Apparatus for producing a gradient gel which serves as a standard medium for a two-dimensional analysis of proteins, the gel having a density gradient along its height formed by a variation in gel composition, with the apparatus including first and second pumping means each including a plurality of pumps on a common shaft and driven by a stepping motor capable of providing small incremental changes in pump outputs for the gel ingredients, the motors being controlled, by digital signals from a digital computer, a hollow form or cassette for receiving the gel composition, means for transferring the gel composition including a filler tube extending near the bottom of the cassette, adjustable horizontal and vertical arms for automatically removing and relocating the filler tube in the next cassette, and a digital computer programmed to automatically control the stepping motors, arm movements, and associated sensing operations involving the filling operation.

  8. Research on pre-staining gel electrophoresis

    Background: Gel electrophoresis is a powerful biochemical separation technique. Most biological molecules are completely transparent in the visible region of light, so it is necessary to use staining to show the results after gel electrophoresis, and the general steps of conventional staining methods are time-consuming. Purpose: We try to develop a novel approach to simplify the gel electrophoresis: Pre-Staining Gel Electrophoresis (PSGE), which can make the gel electrophoresis results monitored in real time. Methods: Pre-stain the protein samples with Coomassie Brilliant Blue (CBB) for 30 min before loading the sample into the gel well. Results and Conclusion: PSGE can be successfully used to analyze the binding efficiency of Bovine Serum Albumin (BSA) and amphiphilic polymer via chemical coupling and physical absorption, and the double PSGE also shows a great potential in bio-analytical chemistry. (authors)

  9. Active Gel Model of Amoeboid Cell Motility

    Callan-Jones, A C

    2013-01-01

    We develop a model of amoeboid cell motility based on active gel theory. Modeling the motile apparatus of a eukaryotic cell as a confined layer of finite length of poroelastic active gel permeated by a solvent, we first show that, due to active stress and gel turnover, an initially static and homogeneous layer can undergo a contractile-type instability to a polarized moving state in which the rear is enriched in gel polymer. This agrees qualitatively with motile cells containing an actomyosin-rich uropod at their rear. We find that the gel layer settles into a steadily moving, inhomogeneous state at long times, sustained by a balance between contractility and filament turnover. In addition, our model predicts an optimal value of the gel-susbstrate adhesion leading to maximum layer speed, in agreement with cell motility assays. The model may be relevant to motility of cells translocating in complex, confining environments that can be mimicked experimentally by cell migration through microchannels.

  10. GEM printer: 3D gel printer for free shaping of functional gel engineering materials

    Furukawa, Hidemitsu; Muroi, Hisato; Yamamoto, Kouki; Serizawa, Ryo; Gong, Jin

    2013-04-01

    In the past decade, several high-strength gels have been developed. These gels are expected to use as a kind of new engineering materials in the fields of industry and medical as substitutes to polyester fibers, which are materials of artificial blood vessels. The gels have both low surface friction and well permeability due to a large amount of water absorbed in the gels, which are superiority of the gels compering to the polyester fibers. It is, however, difficult for gels to be forked structure or cavity structure by using cutting or mold. Consequently, it is necessary to develop the additive manufacturing device to synthesize and mode freely gels at the same time. Here we try to develop an optical 3D gel printer that enables gels to be shaped precisely and freely. For the free forming of high-strength gels, the 1st gels are ground to particles and mixed with 2nd pregel solution, and the mixed solution is gelled by the irradiation of UV laser beam through an optical fiber. The use of the optical fiber makes one-point UV irradiation possible. Since the optical fiber is controlled by 3D-CAD, the precise and free molding in XYZ directions is easily realized. We successfully synthesized tough gels using the gel printer.

  11. Characteristics of polyacrylamide gel with THPC and Turnbull Blue gel dosimeters evaluated using optical tomography

    Pilařová (Vávrů), Kateřina; Kozubíková, Petra; Šolc, Jaroslav; Spěváček, Václav

    2014-11-01

    The purpose of this study was to compare characteristics of radiochromic gel - Turnbull Blue gel (TB gel) with polymer gel - polyacrylamide gel and tetrakis hydroxymethyl phosphonium chloride (PAGAT) using optical tomography. Both types of gels were examined in terms of dose sensitivity, dose response linearity and background value of spectrophotometric absorbance. The calibration curve was obtained for 60Co irradiation performed on Gammacell 220 at predefined gamma dose levels between 0 and 140 Gy for TBG and 0-15 Gy for PAGAT. To measure relative dose distributions from stereotactic irradiation, dosimeters were irradiated on Leksell Gamma Knife Perfexion. The cylindrical glass housings filled with gel were attached to the stereotactic frame. They were exposed with single shot and 16 mm collimator by 65 Gy to a 50% prescription isodose for TB gel and 4 Gy to a 50% prescription isodose for PAGAT. Evaluations of dosimeters were performed on an UV-vis Spectrophotometer Helios β and an optical cone beam homemade tomography scanner with a 16-bit astronomy CCD camera with a set of color filters. The advantages and potential disadvantages for both types of gel dosimeters were summarized. Dose distribution in central slice and measured profiles of 16 mm shot shows excellent correspondence with treatment planning system Leksell GammaPlan® for both PAGAT and Turnbull Blue gels. Gel dosimeters are suitable for steep dose gradient verification. An optical tomography evaluation method is successful. Dose response characteristics of TB gel and PAGAT gel are presented.

  12. Characteristics of polyacrylamide gel with THPC and Turnbull Blue gel dosimeters evaluated using optical tomography

    The purpose of this study was to compare characteristics of radiochromic gel – Turnbull Blue gel (TB gel) with polymer gel – polyacrylamide gel and tetrakis hydroxymethyl phosphonium chloride (PAGAT) using optical tomography. Both types of gels were examined in terms of dose sensitivity, dose response linearity and background value of spectrophotometric absorbance. The calibration curve was obtained for 60Co irradiation performed on Gammacell 220 at predefined gamma dose levels between 0 and 140 Gy for TBG and 0–15 Gy for PAGAT. To measure relative dose distributions from stereotactic irradiation, dosimeters were irradiated on Leksell Gamma Knife Perfexion. The cylindrical glass housings filled with gel were attached to the stereotactic frame. They were exposed with single shot and 16 mm collimator by 65 Gy to a 50% prescription isodose for TB gel and 4 Gy to a 50% prescription isodose for PAGAT. Evaluations of dosimeters were performed on an UV–vis Spectrophotometer Helios β and an optical cone beam homemade tomography scanner with a 16-bit astronomy CCD camera with a set of color filters. The advantages and potential disadvantages for both types of gel dosimeters were summarized. Dose distribution in central slice and measured profiles of 16 mm shot shows excellent correspondence with treatment planning system Leksell GammaPlan® for both PAGAT and Turnbull Blue gels. - highlights: • Gel dosimeters are suitable for steep dose gradient verification. • An optical tomography evaluation method is successful. • Dose response characteristics of TB gel and PAGAT gel are presented

  13. Self-Pumping Active Gel

    Wu, Kun-Ta; Hishamunda, Jean Bernard; Fraden, Seth; Dogic, Zvonimir

    Isotropic active gels are the network which is consist of cross-linked building blocks and the structure of which changes randomly and isotropically with time. Dogic et. al. show that pairs of anti-parallel microtubules form extensile bundles, which merge, extend, and buckle. In an unconfined system, the dynamics of these bundles causes spontaneous turbulent-like flow driven by motion of microscopic molecular motors. We found that confining these active gels in a millimeter sized toroids causes a transition into a new dynamical state characterized by circulation currents persisting for hours until ATP is depleted. We show how toroid dimensions impact the properties of self-organized circular currents, how directions of circulation can be designed by engineering ratchet-shaped boundaries, and how circulations of connected toroids can be either synchronized or antisynchronized. Furthermore, we demonstrate that the flow rate in the circulation is independent of curvature and length of flow path. The flow rate persists for centimeters without decay, disregarding conventional pipe flow resistance. Such findings pave the path to self-pumping pipe transport and performing physical work with biological system.

  14. Microfluidics of soft granular gels

    Nixon, Ryan; Bhattacharjee, Tapomoy; Sawyer, W. Gregory; Angelini, Thomas E.

    Microfluidic methods for encapsulating cells and particles typically involve drop making with two immiscible fluids. The main materials constraint in this approach is surface tension, creating inherent instability between the two fluids. We can eliminate this instability by using miscible inner and outer phases. This is achieved by using granular micro gels which are chemically miscible but physically do not mix. These microgels are yield stress materials, so they flow as solid plugs far from shear gradients, and fluidize where gradients are generated - near an injection nozzle for example. We have found that tuning the yield stress of the material by varying polymer concentration, device performance can be controlled. The solid like behavior of the gel allows us to produces infinitely stable jets that maintain their integrity and configuration over long distances and times. These properties can be combined and manipulated to produce discrete particulate bunches of an inner phase, flowing inside of an outer phase, well enough even to print a Morse code message suspended within flow chambers about a millimeter in diameter moving at millimeters a second.

  15. Stabilized aqueous gels and uses thereof

    Swanson, B.L.

    1978-08-29

    New improved aqueous gels, and methods of using same in contacting subterranean formations, are provided. The gels are prepared by gelling an aqueous brine having incorporated therein a water-soluble cellulose ether such as a carboxymethylcellulose (CMC), and are rendered more stable to decomposition by incorporating a sulfoalkylated tannin stabilizing agent, such as a sulfomethylated quebracho (SMQ), in the gel during the preparation thereof.

  16. Gel time of calcium acrylate grouting material.

    Han, Tong-Chun

    2004-08-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula. PMID:15236477

  17. Structure and Frictional Properties of Colloid Gel

    Masayuki Tokita

    2014-01-01

    Polymer gels are known to be opaque when the preparation conditions, such as the reaction temperature and the composition, are changed. The increase of the opaqueness of the gel suggests strongly the change of network structure. Here, we are going to review the recent studies on the structure and the frictional study of the opaque poly(acrylamide) gel. The results indicate that the opaque poly(acrylamide) gel consists of the fractal aggregate of the colloidal particles of sub-micrometer in si...

  18. Structure of chitosan gels mineralized by sorption

    Modrzejewska, Z.; Skwarczyńska, A.; Douglas, T. E. L.; Biniaś, D.; Maniukiewicz, W.; Sielski, J.

    2015-10-01

    The paper presents the structural studies of mineralized chitosan hydrogels. Hydrogels produced by using sodium beta-glycerophosphate (Na-β-GP) as a neutralizing agent. Mineralization was performed method "post loading", which consisted in sorption to the gels structure Ca ions. In order to obtain - in the structure of gels - compounds similar to the hydroxyapatites present naturally in bone tissue, gels after sorption were modified in: pH 7 buffer and sodium hydrogen phosphate. In order to determine the structural properties of the gels, the following methods were used: infrared spectroscopy with Fourier transformation, FTIR, X-ray diffractometry, XRD, scanning electron microscopy, SEM.

  19. The relationship of agarose gel structure to the sieving of spheres during agarose gel electrophoresis.

    Griess, G A; Guiseley, K B; Serwer, P

    1993-01-01

    To understand the organization of fibers in an agarose gel, digitized electron micrographs are used here to determine the frequency distribution of interfiber distance (2Pc) in thin sections of agarose gels. For a preparation of underivatized agarose, a 1.5% gel has a Pc distribution that is indistinguishable from the Pc distribution of a computer-generated, random-fiber gel; the log of the occurrence frequency (F) decreases linearly as a function of Pc. As the agarose concentration decreases...

  20. Prevalence of Gumboro disease in vaccinated and non-vaccinated village chickens in Egypt

    In order to investigate the incidence of Gumboro disease virus (IBDV) in village poultry in Egypt, 3000 one-day-old Balady chicks were distributed to 60 householders keeping free- ranging chicken (traditional) with an average of 50 chicks/ household. These were put under observed from one-day-old until seventy days of age and visited once a week. On 30 of these household farms the one-day-old chicken were vaccinated before delivery with an intermediate IBDV strain while the chicken on the other 30 farms were not vaccinated. Fifteen of each vaccinated and unvaccinated householder farms had other avian species while the other fifteen of each vaccinated and unvaccinated householders had not. The clinical symptoms, post-mortem and serological results using the Agar Gel Immuno-diffusion test (AGID) revealed that Gumboro disease is one of the most important diseases in rural chicken. Mortality rates were very high (5-32%) and decreasing body weights due to IBDV infection were significant, especially in chicken reared with other avian species. Results from the survey showed the significant efficacy of IBDV classical vaccine in one day old chicken. It showed a decrease in mortality and an increase in body weight gain on vaccinated farms independent whether they were kept with other avian species. Vaccination programs to control Gumboro disease would be an advantage in traditional poultry farms. (author)

  1. Molecular approach to understanding and controlling morbillivirus infections

    Rapid and accurate diagnosis is the most important factor which will determine the success of the current efforts to achieve global eradication of rinderpest. Improved diagnostic capabilities have great relevance for this programme, and molecular biology has provided many valuable new techniques which have been adapted for use in diagnostic and epidemiological studies on viruses. Nucleic acid probe hybridization and monoclonal antibody based ELISAs, which are more sensitive and more specific than classic diagnostic techniques such as agar gel immunodiffusion (AGID) and complement fixation, have proved their usefulness in recent years. However, the most significant advance has been the introduction of the polymerase chain reaction for the detection and identification of disease causing pathogens of medical and veterinary importance. This technique has revolutionized understanding of the epidemiology of rinderpest and other morbiliviruses. Molecular biology has also produced a new generation of recombinant vaccines which will be of use in controlling rinderpest and other morbillivirus diseases, and the molecular basis of morbillivirus pathogenicity is being studied using newly perfected techniques to obtain live virus from DNA copies of their genomes. (author)

  2. EPIDEMIOLOGIA DA INFECÇÃO PELO VÍRUS DA LEUCOSE ENZOÓTICA BOVINA (LEB

    José Wilton Pinheiro Junior

    2013-06-01

    Full Text Available The purpose of this study was to investigate the presence of anti-enzootic leucosis virus antibodies and also to identify the association between seropositivity and management variables for this infection in cattle in the State of Alagoas, Brazil. A total of 17 herds were examined, totaling 341 animals, distributed in eight counties. The antibody detection was performed by the technique of agar gel immunodiffusion (AGID, using the antigen constituted of lipids and proteins from bovine leukosis virus. From the 341 samples analyzed, 95 (27.8% were positive and the number of outbreaks was 12 (70.6%. Significant differences were observed for the variables: technical assistance (p<0.000, recent acquisition of animals (p=0.003, existence of maternity paddocks (p<0.000, and colostrum management (p<0.000. The enzootic bovine leukosis virus infection is present in the region studied and strict sanitary matters must be implemented to prevent spread of the virus, which will avoid losses in the cattle production chain.

  3. Three new serotypes of Rhodococcus equi in Prescott's serotyping system - Short communication.

    Makrai, László; Fodor, László; Hajtós, István; Varga, János; Dénes, Béla

    2015-09-01

    Three new serotypes were found among Rhodococcus equi strains, which could not be assigned into any of the seven serotypes of Prescott's system. Fortythree R. equi strains out of 44 previously nontypable ones isolated in Hungary could be allocated into one of the three new serotypes using the agar gel immunodiffusion (AGID) test. The three new suggested serotypes are serotype 8 (proposed reference strain: HNCMB-138003), serotype 9 (proposed reference strain: HNCMB-138004) and serotype 10 (proposed reference strain: HNCMB-138005). Hyperimmune sera produced in rabbits against the new serotypes and reference strains gave precipitation only with their homologous antigens, and no crossreactions were observed. All of the previously nontypable isolates from clinical samples of horses (lung abscesses, intestinal lymph nodes, mediastinal lymph nodes) proved to be serotype 8, while strains of serotypes 8, 9 and 10 could be isolated from nasal and rectal swabs of horses and from the soil. Serotype 9 dominated among the previously nontypable strains of swine origin. One of the previously nontypable human strains was serotype 10. This serotype was also isolated from pigs, horses and the soil. The description of the three new serotypes can help us reveal new correlations between the host species, geographical origin and serotype of R. equi isolates. PMID:26551416

  4. Sero-epizootiological investigation of infectious laryngotracheitis infection in commercial poultry of Plateau State, north central Nigeria.

    Shittu, Ismaila; Sulaiman, Lanre K; Gado, Dorcas A; Egbuji, Anthony N; Ndahi, Mwapu D; Pam, Ezekiel; Joannis, Tony M

    2016-01-01

    Infectious laryngotracheitis (ILT) is a highly contagious acute respiratory disease of chickens with outbreaks resulting in high economic losses due to increased mortality and drop in egg production. This study reports a survey of ILT virus antibody conducted in nine local government areas (LGAs) of Plateau State involving 67 randomly selected commercial poultry flocks. In all, 938 sera were tested using the Agar Gel Immuno-diffusion (AGID) technique. Overall prevalence of 1.2% (N = 11) was recorded. ILT virus antibody was found in 2.5% (n = 9) and 7.1% (n = 2) of the tested sera from Jos South and Langtang North LGAs, respectively. No detectable ILT virus antibody was found from the other seven LGAs. This is the first report of ILT infection in poultry from the North central part of Nigeria. It is therefore recommended that the economic implication of ILT infection in Nigerian poultry population be conducted in order to know if vaccination should be adopted for control. PMID:26918306

  5. An Epidemiological Situation of an Animal Brucellosis in Mongolia

    S. Nyamdorj

    2012-08-01

    Full Text Available Brucellosis, which is caused by Brucella spp., infects domestic and wild animals worldwide, as well as humans who have contact with infected animals or contaminated dairy products. In present-day epidemiological situation in Mongolia is not quiet, especially, zoonoses such us brucellosis have been broadly spreaded.Recently, we developed agar gel immunodiffusion (AGID test with polysaccharide (Poly-B antigen and an indirect enzyme-linked immunosorbent assay (i-ELISA using soluble antigen extracted from B. abortus 544 by n-lauroylsarcosine (sarcosine extracts and these tests could be used to differentiate naturally infected animals from vaccinated and Y. enterocolitica O9-infected ones; this assay simply and specifically diagnoses brucellosis. To validate the method in the field and to test the effectiveness of the vaccination program in Mongolia, a serological survey of brucellosis in nomadic animal husbandry in Mongolia was performed in 2010 and 2011. In this study had been determined an animal brucellosis prevalence in Arkhangai and Khovd aimag. The result showed that 1.25% and 0.4% of cattle and 0.04 % and 0.01% of small ruminants were positive for brucellosis in Arkhangai and Khovd aimag respectively.These results showed that B.abortus 159 N5R can be used as an alternative vaccine against bovine brucellosis.

  6. Isolation and identification of infectious laryngotracheitis virus from outbreaks at Lipa City, Batangas, Philippines

    Muharam Saepulloh

    2003-06-01

    Full Text Available Infectious laryngotracheitis (ILT is an acute, highly contagious respiratory disease of poultry characterized by respiratory disorder such as coughing with blood exudate from the trachea. The disease is caused by Herpesvirus of the family Herpesviridae and subfamily of Alphaherpesvirus. ILT is worldwide distribution and has been reported to be present in the Philippines since 1980. Since then, confirmation of subsequent outbreaks were not reported. Isolation was conducted from nine commercial layer chicken farms located at Lipa City, Batangas from May to July 2002. Tracheal and lung extracts were processed and inoculated into embryonated chicken eggs by chorio-allantoic membrane (CAM inoculation. Five samples produced typical pock lesions in CAM after the second passage. Lesions observed were yellowish pocks with opaque edges, distributed throughout the CAM. A vaccine strain of the virus used as the positive control also produced similar pock lesions. Serological confirmation using the Agar Gel Immunodiffusion (AGID test showed sharp precipitation lines reacting to a standard reference ILTV antisera (anti-NS175. All five isolates produced lines of precipitate identity among themselves and the positive control. This study confirms that the 2002 disease outbreak in the commercial layer chicken farms in Lipa City, Batangas was due to the ILTV.

  7. Outbreaks of Virulent Infectious Bursal Disease in Flocks of Battery Cage Brooding System of Commercial Chickens

    H. B. Aliyu

    2016-01-01

    Full Text Available Clinical and pathological investigations were conducted on outbreaks of infectious bursal disease (IBD in pullets under brooding using the battery cage system in a commercial poultry farm in Kaduna, Nigeria. Two consecutive outbreaks of IBD on the same farm were studied. The onset of the disease and morbidity and mortality rates were recorded. Postmortem examinations were conducted and gross lesions recorded. Tissues were collected and fixed in 10% buffered formalin and processed for histopathological examinations. In the first outbreak, 80 to 100% of the chicks were affected at the age of 4 to 5 weeks and mortality rate was 95.8% and lasted for 9 days. In the second outbreak, the mortality rate was 43.3% and it also lasted for 9 days. At the onset of the disease, the birds were also 4-week-old like in case 1. The disease was diagnosed based on clinical signs, pathology, and agar gel immunodiffusion test (AGID. Clinical signs, gross lesions, and histopathological findings were characteristic of virulent infectious bursal disease. After the first outbreak (case 1 the house was disinfected using polidine® (iodophor compound, V-ox® (inorganic peroxygen compounds, CID20® (quaternary ammonium chloride, aldehydes, and alcohol, terminator III® (phenols, and glutasan® (aldehyde and quaternary ammonium chloride. But they failed to eliminate the IBD virus from the poultry pen.

  8. Chitosan: Gels and Interfacial Properties

    Julie Nilsen-Nygaard

    2015-03-01

    Full Text Available Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. This review gives an overview of chitosan hydrogels and their biomedical applications, e.g., in tissue engineering and drug delivery, as well as the chitosan’s surface activity and its role in emulsion formation, stabilization and destabilization. Previously unpublished original data where chitosan acts as an emulsifier and flocculant are presented and discussed, showing that highly-acetylated chitosans can act both as an emulsifier and as a flocculant.

  9. Topological characteristics of model gels

    The Euler characteristic of an object is a topological invariant determined by the number of handles and holes that it contains. Here, we use the Euler characteristic to profile the topology of model three-dimensional gel-forming fluids as a function of increasing length scale. These profiles act as a 'topological fingerprint' of the structure, and can be interpreted in terms of three types of topological events. As model fluids we have considered a system of dipolar dumbbells, and suspensions of adhesive hard spheres with isotropic and patchy interactions in turn. The correlation between the percolation threshold and the length scale on which the Euler characteristic passes through zero is examined and found to be system-dependent. A scheme for the efficient calculation of the Euler characteristic with and without periodic boundary conditions is described.

  10. Radiation sensitive polymer gel dosimeters

    Full text: Radiation sensitive gels are studied for their potential to retain a permanent 3D dose distribution for applications in radiotherapy. Co-monomers dissolved in a tissue-equivalent hydrogel undergo a polymerization reaction upon absorption of ionizing radiation. The polymer formed influences the local spin-spin relaxation time (T2) of the dosimeter that can be determined using magnetic resonance imaging (MRI). The relationship between T2 and the absorbed dose was studied for different initial chemical compositions. The aim was to find a model linking the changes in T2 with absorbed dose to the initial composition of the dosimeter. It is believed this will help designing new gel dosimeters having desired properties to minimize the uncertainty in the determination of the dose distribution. 1H, 13C nuclear magnetic resonance spectroscopy and FT-Raman spectroscopy were used to quantify the amount of monomers still remaining after the absorption of a given dose of radiation. This data is used to model the changes of T2 as a function of the absorbed dose. A model of fast exchange of magnetization between three proton pools was used, where the fraction of protons (fxH ) in the xth pool is obtained from the chemical composition of the dosimeter and the apparent T2 of each pool is determined for a given composition. Initially, the protons are contained in two pools; a mobile (mob), which contains the water protons and the monomers protons, and a gelatin (gela) proton pool. The mobile pool is partially depleted as polymer is formed, the protons are transferred into the polymer (pol) pool. In the figure, the experimental data along with the calculated values are plotted for three different monomer concentrations, with the gelatin concentration fixed. The model is seen to provide a good fit to the experimental data

  11. Recrystallization of amylopectin in concentrated starch gels

    Keetels, CJAM; Oostergetel, GT; vanVliet, T

    1996-01-01

    The relation between the recrystallization of amylopectin and the increase in stiffness of starch gels during storage was studied by various techniques. From transmission electron microscopy it was concluded that the size of the crystalline domains in retrograded 30% w/w potato starch gels was about

  12. Serum release boosts sweetness intensity in gels

    Sala, G.; Stieger, M.A.; Velde, van de F.

    2010-01-01

    This paper describes the effect of serum release on sweetness intensity in mixed whey protein isolate/gellan gum gels. The impact of gellan gum and sugar concentration on microstructure, permeability, serum release and large deformation properties of the gels was determined. With increasing gellan g

  13. Cracking silica gels for surface decontamination

    Two types of silica based gels, oxidising and non-oxidising, have been developed and investigated for decontamination of fixed α, β, and γ contamination from contaminated surfaces of glove boxes, PVC floors, fume hood glass doors. Ceric ammonium nitrate dissolved in nitric acid was used as oxidant in oxidising gel. In non-oxidising gel, water soluble reagent; tetra ethyl diglycolamide (TEDGA) in nitric acid was used as complexing agent. Silica gel and PEG-400 was base material in both the cases. The gels were brushed on a stainless steel surface, on drying; these gels crack to yield flakes that were easily scrubbed from the surfaces. The flakes, concentrated in activity, was immobilised in cement for storage. Studies were carried out to investigate the effect of concentrations of oxidant, TEDGA and nitric acid for effective decontamination. Oxidising gels with 0.75 M Ce (IV) and 1 M Nitric acid have shown a maximum DF of 90 for fixed Pu contaminated SS surface. Non-oxidising gel showed a DF of 7 for similar surfaces with 0.075 M TEDGA, 1 M nitric acid and 1 M phosphoric acid. (author)

  14. Structure and Frictional Properties of Colloid Gel

    Masayuki Tokita

    2014-03-01

    Full Text Available Polymer gels are known to be opaque when the preparation conditions, such as the reaction temperature and the composition, are changed. The increase of the opaqueness of the gel suggests strongly the change of network structure. Here, we are going to review the recent studies on the structure and the frictional study of the opaque poly(acrylamide gel. The results indicate that the opaque poly(acrylamide gel consists of the fractal aggregate of the colloidal particles of sub-micrometer in size. The density of the colloid particle is calculated from the structural parameters and is found to be of the order of about 1 g/cm3. The results indicate that the main chain component and the cross-linker is densely cross-linked into the particle. The frictional property of poly(acrylamide gel is analyzed in terms of the structural parameters of the gel. It is found that the frictional property of the opaque gel is well explained in terms of the structural parameters of the opaque gel.

  15. A new polymer gel dosimeter composed of methacrylic acid, agarose gel and THPC with gelatin

    In this paper, a new type of methacrylic acid based gel dosimeter is presented. This gel contains both agarose and gelatin with deferent roles respectively. The agarose conducts itself as a gelling agent, while the gelatin relates to the graft reaction of methacrylic acid. This new type of gel excels in the long-term stability of R2 after irradiation. The characteristics of this gel were studied by the measurements of R2 with MRI and the direct measurements of temperature in the gel during the irradiation.

  16. Intelligent gels and cryogels with entrapped emulsions.

    Komarova, Galina A; Starodubtsev, Sergey G; Lozinsky, Vladimir I; Kalinina, Elena V; Landfester, Katharina; Khokhlov, Alexei R

    2008-05-01

    Smart thermoresponsive gels and cryogels with incorporated emulsions have been synthesized and studied. The gels were obtained by three-dimensional copolymerization of N-isopropylacrylamide and N,N'-methylene-bis-acrylamide or N,N'-bis(acryloyl)cystamine in the presence of dispersion of tetradecane stabilized with sodium dodecylsulfate. Polymerization was performed at room temperature and below the water crystallization temperature. Both composite gels and cryogels were capable of heat-induced collapse. The extent of the collapse of the composite gel prepared at room temperature was much smaller and without squeezing of the lipophilic phase out of the shrunk composite gel. In contrast, shrinking of the composite cryogel was accompanied by release of tetradecane emulsion. PMID:18386880

  17. Radiological properties of normoxic polymer gel dosimeters

    The radiological properties of the normoxic polymer gel dosimeters MAGIC, MAGAS, and MAGAT [methacrylic and ascorbic acid in gelatin initiated by copper; methacrylic acid gelatine gel with ascorbic acid; and methacrylic acid gelatine and tetrakis (hydroxymethyl) phosphonium chloride, respectively] have been investigated. The radiological water equivalence was determined by comparing the polymer gel macroscopic photon and electron interaction cross sections over the energy range from 10 keV to 20 MeV and by Monte Carlo modeling of depth doses. Normoxic polymer gel dosimeters have a high gelatine and monomer concentration and therefore mass density (kg m-3) up to 3.8% higher than water. This results in differences between the cross-section ratios of the normoxic polymer gels and water of up to 3% for the attenuation, energy absorption, and collision stopping power coefficient ratios through the Compton dominant energy range. The mass cross-section ratios were within 2% of water except for the mass attenuation and energy absorption coefficients ratios, which showed differences with water of up to 6% for energies less than 100 keV. Monte Carlo modeling was undertaken for the polymer gel dosimeters to model the electron and photon transport resulting from a 6 MV photon beam. The absolute percentage differences between gel and water were within 1% and the relative percentage differences were within 3.5%. The results show that the MAGAT gel formulation is the most radiological water equivalent of the normoxic polymer gel dosimeters investigated due to its lower mass density measurement compared with MAGAS and MAGIC gels

  18. Ionic liquid gel materials: applications in green and sustainable chemistry

    Marr, Patricia C.; Marr, Andrew C.

    2016-01-01

    Ionic liquid gel materials offer a way to further utilise ionic liquids in technological applications. Combining the controlled and directed assembly of gels, with the diverse applications of ionic liquids, enables the design of a heady combination of functional tailored materials, leading to the development of task specific / functional ionic liquid gels. This review introduces gels and gel classification, focusing on ionic liquid gels and their potential roles in a more sustainable future. ...

  19. Water equivalence of polymer gel dosimeters

    Sellakumar, P. [Bangalore Institute of Oncology, 44-45/2, II Cross, RRMR Extension, Bangalore-560 027 (India)]. E-mail: psellakumar@rediffmail.com; James Jebaseelan Samuel, E. [School of Science and Humanities, Vellore Institute of Technology, Vellore-632 014 (India); Supe, Sanjay S. [Kidwai Memorial Institute of Oncology, Hosur Road, Bangalore-560 027 (India)

    2007-07-15

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z{sub eff}), electron density ({rho}{sub e}), photon mass attenuation coefficient ({mu}/{rho}), photon mass energy absorption coefficient ({mu}{sub en}/{rho}) and total stopping power (S/{rho}){sub tot} of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close (<1%) to that of water except PAGAT, MAGAT and NIPAM which had the variation of 3%, 2% and 3%, respectively. The value of {mu}/{rho} and {mu}{sub en}/{rho} for all polymer gels were in close agreement (<1%) with that of water beyond 80keV. The value of (S/{rho}){sub tot} of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application.

  20. Halogen-bonding-triggered supramolecular gel formation

    Meazza, Lorenzo; Foster, Jonathan A.; Fucke, Katharina; Metrangolo, Pierangelo; Resnati, Giuseppe; Steed, Jonathan W.

    2013-01-01

    Supramolecular gels are topical soft materials involving the reversible formation of fibrous aggregates using non-covalent interactions. There is significant interest in controlling the properties of such materials by the formation of multicomponent systems, which exhibit non-additive properties emerging from interaction of the components. The use of hydrogen bonding to assemble supramolecular gels in organic solvents is well established. In contrast, the use of halogen bonding to trigger supramolecular gel formation in a two-component gel (‘co-gel’) is essentially unexplored, and forms the basis for this study. Here, we show that halogen bonding between a pyridyl substituent in a bis(pyridyl urea) and 1,4-diiodotetrafluorobenzene brings about gelation, even in polar media such as aqueous methanol and aqueous dimethylsulfoxide. This demonstrates that halogen bonding is sufficiently strong to interfere with competing gel-inhibitory interactions and create a ‘tipping point’ in gel assembly. Using this concept, we have prepared a halogen bond donor bis(urea) gelator that forms co-gels with halogen bond acceptors.

  1. Phantom for moving organ dosimetry with gel

    Ravindran, Paul; Babu, Ebenezer Suman [Department of Radiation Oncology, Christian Medical College, Vellore India (India); Mahata, Anurupa [Department of Radiation Oncology, Indo-American Cancer Hospital and Research Institute, Hyderabad (India)], E-mail: paul@cmcvellore.ac.in

    2009-05-01

    The displacements caused by the cardiac and respiratory motions cause smearing of the dose distribution that defeats the purpose of high precision radiotherapy. A phantom that holds a gel cylinder and radiochromic film, was designed and developed to simulate the respiratory motion in the superior and inferior directions. The effect of lung movement on dose distribution was studied by exposing gel as well as a radiochromic film using the phantom. The results obtained with Gel was comparable to those obtained with the radiochromic films.

  2. Phantom for moving organ dosimetry with gel

    Ravindran, Paul; Mahata, Anurupa; Suman Babu, Ebenezer

    2009-05-01

    The displacements caused by the cardiac and respiratory motions cause smearing of the dose distribution that defeats the purpose of high precision radiotherapy. A phontom that holds a gel cylinder and radiochromic film, was designed and developed to simulate the respiratory motion in the superior and inferior directions. The effect of lung movement on dose distribution was studied by exposing gel as well as a radiochromic film using the phantom. The results obtained with Gel was comparable to those obtained with the radiochromic films.

  3. Applications of sol gel ceramic coatings

    The sol gel method is a chemical technique in which polycrystalline ceramic films are fabricated from a solution of organometallic precursors. The technique is attractive for many industrial applications because it is a simple (films are processed in air), flexible (can be used to coat complex geometries) and cost effective (does not require expensive equipment) process. In addition, dense, high quality coatings can be achieved at much lower temperatures than is generally required for sintering bulk ceramics. In this paper the conventional sol gel method and the new datec process are reviewed and potential applications of sol gel coatings in automotive, aerospace, petrochemical, nuclear and electronic industries are discussed. (orig.)

  4. Critical behavior of modulus of gel

    Tokita, Masayuki; Niki, Ryoya; Hikichi, Kunio

    1985-09-01

    The critical behavior of the shear modulus of casein gel is studied. The shear modulus of casein gel scales with the conductivity exponent in the immediate vicinity of the sol-gel transition point. The asymptotic behavior of the modulus in the region far above the transition point is governed by a different exponent which is much larger than the conductivity exponent. These results are explainable by the crossover behavior of the percolation process. This study shows that the gelation of the casein micelle solution is a realization of the percolation process.

  5. Pulsed field gel electrophoresis a practical guide

    Birren, Bruce

    2014-01-01

    Pulsed Field Gel Electrophoresis: A Practical Guide is the first laboratory manual to describe the theory and practice of this technique. Based on the authors' experience developing pulsed field gel instruments and teaching procedures, this book provides everything a researcher or student needs to know in order to understand and carry out pulsed field gel experiments. Clear, well-tested protocols assume only that users have a basic familiarity with molecular biology. Thorough coverage of useful data, theory, and applications ensures that this book is also a lasting resource for more adv

  6. Optical analysis of gel dosimeters: Comparison of Fricke and normoxic polymer gels

    Gambarini, G. [Department of Physics of University, Milan (Italy); National Institute of Nuclear Physics (INFN), Milan (Italy)], E-mail: grazia.gambarini@mi.infn.it; Carrara, M. [Department of Physics of University, Milan (Italy); Department of Physics, National Cancer Institute of Milan (Italy); Mariani, M. [Department of Nuclear Engineering, Polytechnic of Milan (Italy); Pirola, L. [Department of Physics of University, Milan (Italy); Tomatis, S. [Department of Physics, National Cancer Institute of Milan (Italy); Valente, M. [Department of Physics of University, Milan (Italy); National Institute of Nuclear Physics (INFN), Milan (Italy); Vanossi, E. [Department of Nuclear Engineering, Polytechnic of Milan (Italy); National Institute of Nuclear Physics (INFN), Milan (Italy)

    2007-10-15

    The dosimetry method based on optical analysis of gel layers has been experienced utilising both Fricke and polymer (normoxic) gels. The aim of the work was that of investigating the potentiality of a normoxic polymer gel and of performing a further verification of the reliability of Fricke gel dosimeters. Optical absorbance was measured, both with a spectrophotometer and by imaging light transmittance detected with a CCD camera. The results of the study of sensitivity, linearity of the response and reproducibility of the polymer gel dosimeter have shown acceptable performances, except for doses below 2 Gy. The linearity range extends up to 20 Gy. On the other side, dose images and profiles have shown noticeable differences when compared to those calculated or measured with ionisation chambers or Fricke gel dosimeters. Such Fricke dosimeters have given further confirmation of their reliability.

  7. Coordination Polymer Gels by Electron Beam

    Lee, Ji Ha; Cho, Young Je; Jung, Jong Hwa [Gyeongsang National Univ., Jinju (Korea, Republic of)

    2011-07-01

    Hydrogenation of a pyridine derivative possessing tetrazole moieties as end groups, without long alkyl chain groups, results in the formation of a Mg(NO{sub 3}){sub 2} coordination polymer gel. The polymer exhibits a strong fluorescence enhancement upon gel formation. 1 can also be gloated with a variety of magnesium anions such as SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Cl{sup -}, Br{sup -} and I{sup -}, indicating that the coordination polymer gel formation of 1 does not strongly depends on anions. The Seam and ABM images of Mg{sup 2+} coordination polymer gel 1 display a flabbier network with several micrometers long, widths in the range 60-70 nm and thicknesses of about 3 nm. In addition, photophysical studies show that the hydrogel exhibits a typical {pi}-{pi} transition and gives rise to high fluorescence behavior. The coordination polymer hydrogel exhibits viscoelastic behavior as evidenced from the rheological studies.

  8. Coordination Polymer Gels by Electron Beam

    Hydrogenation of a pyridine derivative possessing tetrazole moieties as end groups, without long alkyl chain groups, results in the formation of a Mg(NO3)2 coordination polymer gel. The polymer exhibits a strong fluorescence enhancement upon gel formation. 1 can also be gloated with a variety of magnesium anions such as SO42-, NO3-, Cl-, Br- and I-, indicating that the coordination polymer gel formation of 1 does not strongly depends on anions. The Seam and ABM images of Mg2+ coordination polymer gel 1 display a flabbier network with several micrometers long, widths in the range 60-70 nm and thicknesses of about 3 nm. In addition, photophysical studies show that the hydrogel exhibits a typical π-π transition and gives rise to high fluorescence behavior. The coordination polymer hydrogel exhibits viscoelastic behavior as evidenced from the rheological studies

  9. Sol-gel antireflective coating on plastics

    Ashley, Carol S.; Reed, Scott T.

    1990-01-01

    An antireflection film made from a reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  10. K-Basin gel formation studies

    A key part of the proposed waste treatment for K Basin sludge is the elimination of reactive uranium metal by dissolution in nitric acid (Fkirnent, 1998). It has been found (Delegard, 1998a) that upon nitric acid dissolution of the sludge, a gel sometimes forms. Gels are known to sometimes impair solid/liquid separation and/or material transfer. The purpose of the work reported here is to determine the cause(s) of the gel formation and to determine operating parameters for the sludge dissolution that avoid formation of gel. This work and related work were planned in (Fkunent, 1998), (Jewett, 1998) and (Beck, 1998a). This report describes the results of the tests in (Beck, 1998a) with non-radioactive surrogates

  11. Procedure to prepare transparent silica gels

    Barber, Patrick G. (Inventor); Simpson, Norman R. (Inventor)

    1987-01-01

    This invention relates to the production of silica gels and in particular to a process for the preparation of silica gels which can be used as a crystal growth medium that simulates the convectionless environment of space to produce structurally perfect crystals. Modern utilizations of substances in electronics, such as radio transmitters and high frequency microphones, often require single crystals with controlled purity and structural perfection. The near convectionless environment of silica gel suppresses nucleation, thereby reducing the competitive nature of crystal growth. This competition limits the size and perfection of the crystal; and it is obviously desirable to suppress nucleation until, ideally, only one crystal grows in a predetermined location. A silica gel is not a completely convectionless environment like outer space, but is the closest known environment to that of outer space that can be created on Earth.

  12. Maize Arabinoxylan Gels as Protein Delivery Matrices

    Ana Luisa Martínez-López

    2009-04-01

    Full Text Available The laccase induced gelation of maize bran arabinoxylans at 2.5% (w/v in the presence of insulin or β-lactoglobulin at 0.1% (w/v was investigated. Insulin and β-lacto-globulin did not modify either the gel elasticity (9 Pa or the cross-links content (0.03 and 0.015 mg di- and triferulic acids/mg arabinoxylan, respectively. The protein release capability of the gel was also investigated. The rate of protein release from gels was dependent on the protein molecular weight. The apparent diffusion coefficient was 0.99 × 10-7 and 0.79 × 10-7 cm2/s for insulin (5 kDa and β-lactoglobulin (18 kDa, respectively. The results suggest that maize bran arabinoxylan gels can be potential candidates for the controlled release of proteins.

  13. Thixotropic corrosive gels for nuclear decontamination

    The aim of this thesis was the development of corrosive gels for metallic surface decontamination. These gels formulation, based on a powerful oxidant (the cerium IV), the nitric acid, a mineral charge (silica) and a non ionic surface-active, has been developed according to the specific constraints of the nuclear industry. The objective was to prepare thixotropic gels becoming liquid after shacking to allow an easy pulverization and coming again solid to permit a perfect adhesion on the metallic surface. This rheological study of the gels has been completed by an evaluation of their corrosive properties. The last part of the work presents an industrial utilization during two years. (A.L.B.)

  14. Radiation protection on polysaccharide solutions and gels

    The effects of ionizing radiation on solutions of (1) sodium alginate, (2) alginate gels (wet and dry), (3) xanthan glum, (4), locust bean gum (LBG) and (5) carboxymethyl cellulose (CMC), have been investigated. Problems arise in the radiation sterilization of these gums (either as a solution or gel) due to reduction in their viscosity and the gel strength, caused by the high doses (25kGy) commonly used for the purpose of sterilization. The alginates used here were manugel DMB, manugel DPB and manucol DMF. The irradiations were carried out using 60Co-γ-source and the gels and solutions were analysed by measurement of their apparent viscosities using a Brookfield viscometer L.V.T. (author)

  15. GEL criteria for moment condition models

    Smith, Richard J.

    2004-01-01

    GEL methods which generalize and extend previous contributions are defined and analysed for moment condition models specified in terms of weakly dependent data. These procedures offer alternative one-step estimators and tests that are asymptotically equivalent to their efficient two-step GMM counterparts. The basis for GEL estimation is via a smoothed version of the moment indicators using kernel function weights which incorporate a bandwidth parameter. Examples for the choice of bandwidth pa...

  16. Denaturing Urea Polyacrylamide Gel Electrophoresis (Urea PAGE)

    Summer, Heike; Grämer, René; Dröge, Peter

    2009-01-01

    Urea PAGE or denaturing urea polyacrylamide gel electrophoresis employs 6-8 M urea, which denatures secondary DNA or RNA structures and is used for their separation in a polyacrylamide gel matrix based on the molecular weight. Fragments between 2 to 500 bases, with length differences as small as a single nucleotide, can be separated using this method1. The migration of the sample is dependent on the chosen acrylamide concentration. A higher percentage of polyacrylamide resolves lower molecula...

  17. Halogen-bonding-triggered supramolecular gel formation.

    Meazza, L.; Foster, J. A.; Fucke, K.; Metrangolo, P.; Resnati, G.; Steed, J. W.

    2013-01-01

    Supramolecular gels are topical soft materials involving the reversible formation of fibrous aggregates using non-covalent interactions. There is significant interest in controlling the properties of such materials by the formation of multicomponent systems, which exhibit non-additive properties emerging from interaction of the components. The use of hydrogen bonding to assemble supramolecular gels in organic solvents is well established. In contrast, the use of halogen bonding to trigger sup...

  18. Preprocessing of 1D gel electrophoresis image

    Hlavatý, Matej

    2015-01-01

    Gel electrophoresis is an important method used for separation and analysis of macromolecules with electric potential. This well-established method has a big potential in medicine and science, however, the output images often suffer from distortion. This work describes several known sources of distortion and elaborates on existing methods of the track detection in gel electrophoresis. The core of this thesis introduces a new method to detect individual tracks and image pre-processing based on...

  19. Conducting Polymer Electrodes for Gel Electrophoresis

    Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that p-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel ...

  20. Sol-Gels for Optical Sensors

    Podbielska, Halina; Ulatowska-Jarża, Agnieszka; Müller, Gerhard; Eichler, Hans J.

    Sol-gel process allows for formation of glassy and ceramics materials in temperatures much lower than offered by conventional melting techniques. The first paper on sol-gels was published over 150 years ago by Ebelmen, however, the rapid development of this technology and applications occurred in the last few years. There is a broad range of possible applications of solgel derived materials, what marked this technology as one of the most promising fields of contemporary material sciences

  1. Rheological Characterization of Ethanolamine Gel Propellants

    V. S Jyoti, Botchu; Baek, Seung Wook

    2016-07-01

    Ethanolamine is considered to be an environmentally friendly propellant system because it has low toxicity and is noncarcinogenic in nature. In this article, efforts are made to formulate and prepare ethanolamine gel systems, using pure agarose and hybrids of paired gelling agents (agarose + polyvinylpyrrolidine (PVP), agarose + SiO2, and PVP + SiO2), that exhibit a measurable yield stress, thixotropic behavior under shear rate ranges of 1-1,000 s-1 and a viscoelastic nature. To achieve these goals, multiple rheological experiments (including flow and dynamic studies) are performed. In this article, results are presented from experiments measuring the apparent viscosity, yield stress, thixotropy, dynamic strain, frequency sweep, and tan δ behaviors, as well as the effects of the test temperature, in the gel systems. The results show that the formulated ethanolamine gels are thixotropic in nature with yield stress between 30 and 60 Pa. The apparent viscosity of the gel decreases as the test temperature increases, and the apparent activation energy is the lowest for the ethanolamine-(PVP + SiO2) gel system. The dynamic rheology study shows that the type of gellant, choice of hybrid gelling materials and their concentration, applied frequencies, and strain all vitally affect the viscoelastic properties of the ethanolamine gel systems. In the frequency sweep experiment, the ethanolamine gels to which agarose, agarose + PVP, and agarose + SiO2 were added behave like linear frequency-dependent viscoelastic liquids, whereas the ethanolamine gel to which PVP + SiO2 was added behaves like a nearly frequency-independent viscoelastic solid. The variation in the tan δ of these gelled propellants as a function of frequency is also discussed.

  2. Sol-gel derived PZT fibers

    Sol-gel routes were developed to prepare densified PZT fibers. The effects of the degree of hydrolysis and the addition of an organic polymer to the precursor sol on fiber forming ability were investigated. In this paper results on the crystalline and microstructural development of gels and fibers are presented. The effects of the incorporation of excess PbO and sintering atmosphere are also discussed, particularly in relation to densification

  3. Dynamic Scaling of Polymer Gels Comprising Nanoparticles

    Teixeira, Alvaro V. N. C.; Geissler, Erik; Licinio, Pedro

    2014-01-01

    We present dynamic light scattering (DLS) measurements of soft polymethyl-methacrylate (PMMA) and polyacrylamide(PA) polymer gels prepared with trapped bodies (latex spheres or maghemite nanoparticles). We show that the anomalous diffusivity of the trapped particles can be analyzed in terms of a fractal Gaussian network gel model for the entire time range probed by DLS technique. This model is a generalization of the Rouse model for linear chains extended for structures with power law network...

  4. Structure Formation in Acid Milk Gels

    Heertje, I.; Visser, J.; Smits, P

    1985-01-01

    The structure formation in acid milk gels is influenced by many factors such as heat, salt system, pH, culture and thickening agents. Understanding of the mechanism of structure formation is important in order to be able to influence the final texture of these products. In the present study the network formation in acid milk gels during acidification is monitored by freeze-fracture electron microscopy. Network formation appears to be a much more complex process than just an aggregation of ...

  5. Carbon gels derived from natural resources

    Celzard, A.; Fierro, V.; Amaral-Labat, G.; Szczurek, A.; Braghiroli, F.; Parmentier, J.; Pizzi, A.; Grishechko, L. I.; Kuznetsov, B. N.

    2012-01-01

    [EN] Most carbon gels investigated so far and reported in the literature were prepared from resorcinol crosslinked with formaldehyde in water, and were generally dried with supercritical CO2 before being pyrolysed. In the present paper, through some selected examples, we show how valuable carbon gels can be derived from other phenolic resources having a natural origin. Special emphasis is given to tannin and lignin, both derived from wood, as potential precursors of...

  6. Optimized MR imaging for polyacrylamide gel dosimetry

    Polyacrylamide gels are a powerful tool to measure radiation dose by quantifying the NMR T2 relaxation times of the irradiated gel. The exploitation of these radiation sensitive gels in clinical radiotherapy requires accurate mapping of T2 values. This paper describes the optimization strategy used to identify accurate and practical methods of measuring the range of T2 values typical of gel dosimeters (140-700 ms). The MR imaging techniques used to measure T2 values and the choice of image acquisition parameters are described. Four sequences are compared and the results are analysed in terms of accuracy, signal-to-noise ratio and acquisition time. A multiple spin echo sequence was found to yield the most accurate results (98.9%). Single spin echo sequences, such as Hahn spin echo and EPI spin echo, were found to measure gel T2 values with an accuracy of 90.1%. This paper reports the importance of careful selection and optimization of the MR imaging sequences for accurate and reliable polyacrylamide gel dosimetry. (author)

  7. Treatment of osteochondral injuries with platelet gel

    Marcus Vinicius Danieli

    2014-12-01

    Full Text Available OBJECTIVES: Treatments for injured articular cartilage have not advanced to the point that efficient regeneration is possible. However, there has been an increase in the use of platelet-rich plasma for the treatment of several orthopedic disorders, including chondral injuries. Our hypothesis is that the treatment of chondral injuries with platelet gel results in higher-quality repair tissue after 180 days compared with chondral injuries not treated with gel. METHODS: A controlled experimental laboratory study was performed on 30 male rabbits to evaluate osteochondral injury repair after treatment with or without platelet gel. Osteochondral injuries were surgically induced in both knees of each rabbit at the medial femoral condyle. The left knee injury was filled with the platelet gel, and the right knee was not treated. Microscopic analysis of both knee samples was performed after 180 days using a histological grading scale. RESULTS: The only histological evaluation criterion that was not significantly different between treatments was metachromasia. The group that was treated with platelet gel exhibited superior results in all other criteria (cell morphology, surface regularity, chondral thickness and repair tissue integration and in the total score. CONCLUSION: The repair tissue was histologically superior after 180 days in the study group treated with platelet gel compared with the group of untreated injuries.

  8. Cavitation of a Physically Associating Gel

    Mishra, Satish; Kundu, Santanu

    Self-assembly of block copolymers in selective solvents form ordered structures such as micelles, vesicles, and physically crosslinked gels due to difference in their interaction with solvents. These gels have wide range of applications in tissue engineering, food science and biomedical field due to their tunable properties and responsiveness with changing environmental conditions. Pressurization of a defect inside a physically associating gel can lead to elastic instability (cavitation) leading to failure of the gel. The failure behavior involves dissociation of physical networks. A thermoreversible, physically associating gel with different volume fractions of a triblock copolymer, poly (methyl methacrylate)-poly (n-butyl acrylate)-poly (methyl methacrylate) [PMMA-PnBA-PMMA] in 2-ethyl 1-hexanol, a midblock selective solvent, is considered here. Mechanical properties were investigated using shear rheology and cavitation experiments. The experimental data is fitted with a constitutive model that captures the stiffening behavior followed by softening behavior of a physical gel. Finite element analysis has been performed on cavitation rheology geometry to capture the failure behavior and to calculate energy release rate during cavitation experiments.

  9. Study of nuclear glasses alteration gel and synthesis of some model gels; Etude du gel d`alteration des verres nucleaires et synthese de gels modeles

    Ricol, S.

    1995-10-05

    This work deals with the general problem of alteration of the reference nuclear glass R7T7. Attention is paid particularly to the altered layer formed at the glass surface during alteration process. In opposition to previous works, related essentially to glass dissolution kinetics based on chemical analyses of lixiviated elements, this thesis deals with alteration problems through structural studies of the reference glass and derived gel. This approach allows the determination of mechanisms for the gel formation and a better understanding of the behaviour of glasses towards lixiviation. Both approaches appeared complementary. Based on several spectroscopic techniques, this work showed the particular role of cations such as calcium, zirconium and iron. Studies of silica-based synthetic gels showed the synergic effect of formers cation and of one highly coordinated cation. The variation of the wavenumber related to Si-O-Si asymmetric stretching vibration can be correlated to O/Si ratio for ternary systems Si/Na/Zr. On the contrary, the Si losses of the materials depend on the number of non-bridging oxygen atoms. In the perspective of long-term behaviour, the alteration gel presents better characteristics than initial glass. It is therefore a highly stable material in static conditions. In the same way, synthetic gels are materials with very low solubilities (much lower than the alteration gel) and could be used as confining matrices. (authors). refs., 71 figs., 37 tabs.

  10. Gel electrolyte for lithium-ion batteries

    Chen, Zonghai; Amine, K. [Chemical Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Zhang, L.Z.; West, R. [Organosilicon Research Center, Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (United States)

    2008-03-10

    The electrochemical performance of gel electrolytes based on crosslinked poly[ethyleneoxide-co-2-(2-methoxyethyoxy)ethyl glycidyl ether-co-allyl glycidyl ether] was investigated using graphite/Li{sub 1.1}[Ni{sub 1/3}Mn{sub 1/3}Co{sub 1/3}]{sub 0.9}O{sub 2} lithium-ion cells. It was found that the conductivity of the crosslinked gel electrolytes was as high as 5.9 mS/cm at room temperature, which is very similar to that of the conventional organic carbonate liquid electrolytes. Moreover, the capacity retention of lithium-ion cells comprising gel electrolytes was also similar to that of cells with conventional electrolytes. Despite of the high conductivity of the gel electrolytes, the rate capability of lithium-ion cells comprising gel electrolytes is inferior to that of the conventional cells. The difference was believed to be caused by the poor wettability of gel electrolytes on the electrode surfaces. (author)

  11. Gel electrolyte for lithium-ion batteries

    Chen Zonghai [Chemical Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Zhang, L.Z.; West, R. [Organosilicon Research Center, Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (United States); Amine, K. [Chemical Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)], E-mail: amine@cmt.anl.gov

    2008-03-10

    The electrochemical performance of gel electrolytes based on crosslinked poly[ethyleneoxide-co-2-(2-methoxyethyoxy)ethyl glycidyl ether-co-allyl glycidyl ether] was investigated using graphite/Li{sub 1.1}[Ni{sub 1/3}Mn{sub 1/3}Co{sub 1/3}]{sub 0.9}O{sub 2} lithium-ion cells. It was found that the conductivity of the crosslinked gel electrolytes was as high as 5.9 mS/cm at room temperature, which is very similar to that of the conventional organic carbonate liquid electrolytes. Moreover, the capacity retention of lithium-ion cells comprising gel electrolytes was also similar to that of cells with conventional electrolytes. Despite of the high conductivity of the gel electrolytes, the rate capability of lithium-ion cells comprising gel electrolytes is inferior to that of the conventional cells. The difference was believed to be caused by the poor wettability of gel electrolytes on the electrode surfaces.

  12. Preparation of continuous alumina gel fibres by aqueous sol–gel process

    Hongbin Tan; Xiaoling Ma; Mingxing Fu

    2013-02-01

    Continuous alumina gel fibres were prepared by sol–gel method. The spinning sol was prepared by mixing aluminum nitrate, lactic acid and polyvinylpyrrolidone with a mass ratio of 10:3:1.5. Thermogravimetry–differential scanning calorimetry (TG–DSC), Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the properties of the gel and ceramic fibres. The Al2O3 fibres with a uniform diameter can be obtained by sintering gel fibres at 1200 °C.

  13. The fundamental radiation properties of normoxic polymer gel dosimeters: a comparison between a methacrylic acid based gel and acrylamide based gels

    Polymer gel dosimeters offer a wide range of applications in the three-dimensional verification of complex dose distributions such as in intensity-modulated radiotherapy. One of the major difficulties with polymer gel dosimeters is their sensitivity to oxygen, as oxygen inhibits the radiation-induced polymerization reaction. For several years, oxygen was removed from the gels by bubbling the sol with inert gases for several hours during the gel fabrication. Also, the gel had to be poured in containers with low oxygen permeability and solubility. Recently, it was found that these technical difficulties can easily be solved by adding an antioxidant to the gel. These gels are called 'normoxic' gels as they can be produced under normal atmospheric conditions. In this study several properties of polymer gel dosimeters have been investigated: the dose sensitivity, the temporal and spatial stability of the gel, the sensitivity of the dose response to temperature during irradiation and during MR imaging, the energy dependence and the dose-rate dependence. This study reveals that the normoxic polymer gel dosimeter based on methacrylic acid (nMAG) studied in this work has inferior radiation properties as compared to the polyacrylamide gelatine (PAG) gel dosimeters. It is shown that from the three different gel dosimeters investigated in this study, the nPAG gel dosimeter results in a less sensitive gel dosimeter but with superior radiation properties as compared to the nMAG gel dosimeter. The importance of investigating relevant radiation properties of gel dosimeters apart from the radiation sensitivity-prior to their use for dosimetric validation experiments-is illustrated and emphasized throughout this study. Other combinations of monomer and gelling agent may result in more reliable normoxic polymer gel dosimeters

  14. Natural gels in the Yucca Mountain Area, Nevada, USA

    Relict gels at Yucca Mountain include pore- and fracture-fillings of silica and zeolite related to diagenetic and hydrothermal alternation of vitric tuffs. Water-rich free gels in fractures at Rainier Mesa consist of smectite with or without silica-rich gel fragments. Gels are being studied for their potential role in transport of radionuclides from a nuclear-waste repository

  15. Uncertainty in 3D gel dosimetry

    De Deene, Yves; Jirasek, Andrew

    2015-01-01

    Three-dimensional (3D) gel dosimetry has a unique role to play in safeguarding conformal radiotherapy treatments as the technique can cover the full treatment chain and provides the radiation oncologist with the integrated dose distribution in 3D. It can also be applied to benchmark new treatment strategies such as image guided and tracking radiotherapy techniques. A major obstacle that has hindered the wider dissemination of gel dosimetry in radiotherapy centres is a lack of confidence in the reliability of the measured dose distribution. Uncertainties in 3D dosimeters are attributed to both dosimeter properties and scanning performance. In polymer gel dosimetry with MRI readout, discrepancies in dose response of large polymer gel dosimeters versus small calibration phantoms have been reported which can lead to significant inaccuracies in the dose maps. The sources of error in polymer gel dosimetry with MRI readout are well understood and it has been demonstrated that with a carefully designed scanning protocol, the overall uncertainty in absolute dose that can currently be obtained falls within 5% on an individual voxel basis, for a minimum voxel size of 5 mm3. However, several research groups have chosen to use polymer gel dosimetry in a relative manner by normalizing the dose distribution towards an internal reference dose within the gel dosimeter phantom. 3D dosimetry with optical scanning has also been mostly applied in a relative way, although in principle absolute calibration is possible. As the optical absorption in 3D dosimeters is less dependent on temperature it can be expected that the achievable accuracy is higher with optical CT. The precision in optical scanning of 3D dosimeters depends to a large extend on the performance of the detector. 3D dosimetry with X-ray CT readout is a low contrast imaging modality for polymer gel dosimetry. Sources of error in x-ray CT polymer gel dosimetry (XCT) are currently under investigation and include inherent

  16. Hexagonal phase based gel-emulsion (O/H1 gel-emulsion): formation and rheology.

    Alam, Mohammad Mydul; Aramaki, Kenji

    2008-11-01

    The formation, stability, and rheological behavior of a hexagonal phase based gel-emulsion (O/H1 gel-emulsion) have been studied in water/C12EO8/hydrocarbon oil systems. A partial phase behavior study indicates that the oil nature has no effect on the phase sequences in the ternary phase diagram of water/C12EO8/oil systems but the domain size of the phases or the oil solubilization capacity considerably changes with oil nature. Excess oil is in equilibrium with the hexagonal phase (H1) in the ternary phase diagram in the H1+O region. The O/H1 gel-emulsion was prepared (formation) and kept at 25 degrees C to check stability. It has been found that the formation and stability of the O/H1 gel-emulsion depends on the oil nature. After 2 min observation (formation), the results show that short chain linear hydrocarbon oils (heptane, octane) are more apt to form a O/H1 gel-emulsion compared to long chain linear hydrocarbon oils (tetradecane, hexadecane), though the stability is not good enough in either system, that is, oil separates within 24 h. Nevertheless, the formation and stability of the O/H1 gel-emulsion is appreciably increased in squalane and liquid paraffin. It is surmised that the high transition temperature of the H1+O phase and the presence of a bicontinuous cubic phase (V1) might hamper the formation of a gel-emulsion. It has been pointed out that the solubilization of oil in the H1 phase could be related to emulsion stability. On the other hand, the oil nature has little or no effect on the formation and stability of a cubic phase based gel-emulsion (O/I1 gel-emulsion). From rheological measurements, it has found that the rheogram of the O/H1 gel-emulsion indicates gel-type structure and shows shear thinning behavior similar to the case of the O/I1 gel-emulsion. Rheological data infer that the O/I1 gel-emulsion is more viscous than the O/H1 gel-emulsion at room temperature but the O/H1 gel-emulsion shows consistency at elevated temperature. PMID:18847293

  17. Different Applications of Rheological Techniques in Studies of Physical Gels

    Hvidt, Søren

    Physical gels are of both great scientific and practical interest. The cytoplasm of cells, which consists of a complex physical gel of protein filaments, is important for most of the cellular processes including cell division and cell motility. Nature has developed this complex system of...... biopolymer and physical gels [1,2]. The nature of physical gels has been debated for many years. In contrast to chemically crosslinked gels physical gels are often thermoreversible and small changes in e.g. temperature, pH or ionic strength may shift the system from a gel state to a sol state. Ole Kramer [3......] pointed out the importance of time scales for physical gels. According to him the characteristic property of a gel is the presence of two components and a constant elastic storage modulus on time scales of 1 s or frequencies of 1 rad/s. His definition of gels relies on their rheological properties...

  18. Fabricating porous materials using interpenetrating inorganic-organic composite gels

    Seo, Dong-Kyun; Volosin, Alex

    2016-06-14

    Porous materials are fabricated using interpenetrating inorganic-organic composite gels. A mixture or precursor solution including an inorganic gel precursor, an organic polymer gel precursor, and a solvent is treated to form an inorganic wet gel including the organic polymer gel precursor and the solvent. The inorganic wet gel is then treated to form a composite wet gel including an organic polymer network in the body of the inorganic wet gel, producing an interpenetrating inorganic-organic composite gel. The composite wet gel is dried to form a composite material including the organic polymer network and an inorganic network component. The composite material can be treated further to form a porous composite material, a porous polymer or polymer composite, a porous metal oxide, and other porous materials.

  19. Pouring and Running a Protein Gel by reusing Commercial Cassettes

    Hwang, Alexander C.; Grey, Paris H.; Cuddy, Katrina; Oppenheimer, David G.

    2012-01-01

    The evaluation of proteins using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis is a common technique used by biochemistry and molecular biology researchers1-4. For laboratories that perform daily analyses of proteins, the cost of commercially available polyacrylamide gels (˜$10/gel) can be considerable over time. To mitigate this cost, some researchers prepare their own polyacrylamide gels. Traditional methods of pouring these gels typically utilize specialized...

  20. Interaction between hepatocytes and collagen gel in hollow fibers

    Dai, Jing; Zhang, Guo-Liang; Meng, Qin

    2009-01-01

    Gel entrapment culture of primary mammalian cells within collagen gel is one important configuration for construction of bioartificial organ as well as in vitro model for predicting drug situation in vivo. Gel contraction in entrapment culture, resulting from cell-mediated reorganization of the extracellular matrix, was commonly used to estimate cell viability. However, the exact influence of gel contraction on cell activities has rarely been addressed. This paper investigated the gel contrac...

  1. Characterization of schistosome antigens by SDS-polyacrylamide gel electrophoresis

    Separation of polypeptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) is based upon the relationship between the electrophoretic mobility of SDS-protein complexes and their molecular weights. Tegumental proteins extracted from Schistosoma mansoni have been analyzed by SDS-PAGE using slab gels by a number of investigators. Valuable information has also been obtained using tube gels to analyze radiolabeled proteins. The procedures for electrophoresis using tube gels and electrophoresis using gradient slab gels are described

  2. Optimal processing for gel electrophoresis images: Applying Monte Carlo Tree Search in GelApp.

    Nguyen, Phi-Vu; Ghezal, Ali; Hsueh, Ya-Chih; Boudier, Thomas; Gan, Samuel Ken-En; Lee, Hwee Kuan

    2016-08-01

    In biomedical research, gel band size estimation in electrophoresis analysis is a routine process. To facilitate and automate this process, numerous software have been released, notably the GelApp mobile app. However, the band detection accuracy is limited due to a band detection algorithm that cannot adapt to the variations in input images. To address this, we used the Monte Carlo Tree Search with Upper Confidence Bound (MCTS-UCB) method to efficiently search for optimal image processing pipelines for the band detection task, thereby improving the segmentation algorithm. Incorporating this into GelApp, we report a significant enhancement of gel band detection accuracy by 55.9 ± 2.0% for protein polyacrylamide gels, and 35.9 ± 2.5% for DNA SYBR green agarose gels. This implementation is a proof-of-concept in demonstrating MCTS-UCB as a strategy to optimize general image segmentation. The improved version of GelApp-GelApp 2.0-is freely available on both Google Play Store (for Android platform), and Apple App Store (for iOS platform). PMID:27251892

  3. Sol-gel processing of metal sulfides

    Stanic, Vesha

    Metal sulfides were synthesised via a sol-gel process using various metal alkoxides and hydrogen sulfide in toluene. Colloidal gels were prepared from germanium ethoxide, germanium isopropoxide, zinc tert-butoxide and tungsten (VI) ethoxide, whereas colloidal powder was produced from tungsten (V) dichloride ethoxide. Special precautions were necessary to protect the reaction mixture from water contamination which produced metal oxides. Results indicated that the main source of water is the hydrogen sulfide gas. In addition, synthesis of metal sulfides from a mixture of metal oxide and sulfide was demonstrated by the example of monoclinic germanium disulfide. It was produced by reaction of the sol-gel product with sulfur. Heat treatment of the sol-gel product and sulfur yielded single phase GeSsb2. The sol-gel prepared materials and their heat treated products were characterized by various methods. A chemical kinetics study of the functional groups -OR, -SH and Ssp{2-} was carried out for the sol-gel processing of GeSsb2 from of hydrogen sulfide and two different alkoxides, germanium ethoxide and germanium isopropoxide. The study was performed for different concentrations of precursors at different molar ratios and temperatures. The results indicate that the proposed reaction mechanism was simplified under appropriate reaction conditions. Experimentally determined rate constants of thiolysis and condensations demonstrate that thiolysis is slow and that condensations are fast steps, regardless of the studied reaction conditions. A study of the temperature effect on the reaction rate constant shows that it increases with temperature in accord with both Arrhenius law and transition-state theory. Activation energies, Esba, and activation parameters DeltaSsp{ddagger}, DeltaHsp{ddagger} and DeltaGsp{ddagger}, were determined for thiolysis and condensation reactions. The potentiometric tiration method was used for quantitative determination of germanium sulfide and

  4. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  5. Continuum Models of Stimuli-responsive Gels

    Hong, Wei

    Immersed in a solution of small molecules and ions, a network of long-chain polymers may imbibe the solution and swell, resulting in a polymeric gel. Depending on the molecular structure of the polymers, the amount of swelling can be regulated by moisture, mechanical forces, ionic strength, electric field, pH value, and many other types of stimuli. Starting from the basic principles of non-equilibrium thermodynamics, this chapter formulates a field theory of the coupled large deformation and mass transportation in a neutral polymeric gel. The theory is then extended to study polyelectrolyte gels with charge-carrying networks by accounting for the electromechanical coupling and migration of solute ions. While the theoretical framework is adaptable to various types of material models, some representative ones are described through specific free-energy functions and kinetic laws. A specific material law for pH-sensitive gels—a special type of polyelectrolyte gels—is introduced as an example of incorporating chemical reactions in modeling stimuli-responsive gels. Finally, a simplified theory for the equilibrium but inhomogeneous swelling of a polymeric gel is deduced. The theory and the specific material models are illustrated through several examples.

  6. Structural evolution of Colloidal Gels under Flow

    Boromand, Arman; Maia, Joao; Jamali, Safa

    Colloidal suspensions are ubiquitous in different industrial applications ranging from cosmetic and food industries to soft robotics and aerospace. Owing to the fact that mechanical properties of colloidal gels are controlled by its microstructure and network topology, we trace the particles in the networks formed under different attraction potentials and try to find a universal behavior in yielding of colloidal gels. Many authors have implemented different simulation techniques such as molecular dynamics (MD) and Brownian dynamics (BD) to capture better picture during phase separation and yielding mechanism in colloidal system with short-ranged attractive force. However, BD neglects multi-body hydrodynamic interactions (HI) which are believed to be responsible for the second yielding of colloidal gels. We envision using dissipative particle dynamics (DPD) with modified depletion potential and hydrodynamic interactions, as a coarse-grain model, can provide a robust simulation package to address the gel formation process and yielding in short ranged-attractive colloidal systems. The behavior of colloidal gels with different attraction potentials under flow is examined and structural fingerprints of yielding in these systems will be discussed.

  7. Mucosal effects of tenofovir 1% gel.

    Hladik, Florian; Burgener, Adam; Ballweber, Lamar; Gottardo, Raphael; Vojtech, Lucia; Fourati, Slim; Dai, James Y; Cameron, Mark J; Strobl, Johanna; Hughes, Sean M; Hoesley, Craig; Andrew, Philip; Johnson, Sherri; Piper, Jeanna; Friend, David R; Ball, T Blake; Cranston, Ross D; Mayer, Kenneth H; McElrath, M Juliana; McGowan, Ian

    2015-01-01

    Tenofovir gel is being evaluated for vaginal and rectal pre-exposure prophylaxis against HIV transmission. Because this is a new prevention strategy, we broadly assessed its effects on the mucosa. In MTN-007, a phase-1, randomized, double-blinded rectal microbicide trial, we used systems genomics/proteomics to determine the effect of tenofovir 1% gel, nonoxynol-9 2% gel, placebo gel or no treatment on rectal biopsies (15 subjects/arm). We also treated primary vaginal epithelial cells from four healthy women with tenofovir in vitro. After seven days of administration, tenofovir 1% gel had broad-ranging effects on the rectal mucosa, which were more pronounced than, but different from, those of the detergent nonoxynol-9. Tenofovir suppressed anti-inflammatory mediators, increased T cell densities, caused mitochondrial dysfunction, altered regulatory pathways of cell differentiation and survival, and stimulated epithelial cell proliferation. The breadth of mucosal changes induced by tenofovir indicates that its safety over longer-term topical use should be carefully monitored. PMID:25647729

  8. Superconductive ceramics obtained with sol gel method

    Several sol gel routes have been considered, studied and developed to produce large quantities of granulates which can be processed to obtain ceramics having good superconducting characteristics. In the considered process a mixture of commercial nitrates is atomized, at room temperature, in a solution 1:1 of Primene JMT and Benzene and a pale blue gel of the starting elements is suddently formed. The granulates obtained are free flowing, very reactive and well suited for pressing. For their intrinsic characteristics they could be very good precursors for the production of large quantities of superconductive ceramics in different forms. The precipitated gel is dried, calcinated, pressed in the form of cylindrical pellets which are sintered up to 960 degrees C. No griding or different thermal treatments are needed. The sintered material has low electric resistence, shows a clear Meissner effect and has a transition temperature of between 91 and 95 K

  9. Carbon gels derived from natural resources

    A. Celzard

    2012-12-01

    Full Text Available Most carbon gels investigated so far and reportedin the literature were prepared from resorcinolcrosslinked with formaldehyde in water, and weregenerally dried with supercritical CO2 before beingpyrolysed. In the present paper, through someselected examples, we show how valuable carbongels can be derived from other phenolic resourceshaving a natural origin. Special emphasis is givento tannin and lignin, both derived from wood, aspotential precursors of carbon aero- and cryogels.However, natural compounds not obeying the usualconcepts of sol-gel chemistry may also be used forpreparing carbon gels, such as cellulose, and evenglucose. In the latter case, hydrothermal treatmentforces the phase separation to occur, and leads tomonoliths which can be advantageously convertedinto carbon aerogels by supercritical drying andsubsequent pyrolysis.

  10. On the scattering properties of polyelectrolyte gels

    Barrat, Jean-Louis; Joanny, Jean-François; Pincus, Phil

    1992-08-01

    We present a simple model for scattering properties of polyelectrolyte gels at swelling equilibrium. In the weak screening limit where the Debye-Hückel screening length is larger than the mesh size of the gel, the direct electrostatic interactions are negligible and the swelling is driven by the osmotic pressure of the counterions. The tension created by this pressure is transmitted through the crosslinks to the elastic chains which behave as isolated chains with an applied force at their end points. The structure factor of the gel can be split into a frozen component due to the average concentration heterogeneities and a thermodynamic component due to concentration fluctuations. The frozen component has a peak at a wavevector of the order of the mesh size of the gel, the thermodynamic component has a peak at a higher wavevector of the order of the inverse transverse radius of the chains. At infinite times the dynamic structure factor relaxes towards the frozen component of the static structure factor. In the limit of small wavevectors the relaxation is diffusive with a diffusion constant equal to the Stokes diffusion constant of the Pincus blobs of the stretched chains. The diffusion constant shows a minimum at a wavevector of the order of the inverse transverse radius of the chains. Nous présentons un modèle simple pour étudier la diffusion de rayonnement par des gels polylectrolytes à l'équilibre de gonflement. Dans la limite d'écrantage faible où la longueur d'écran de Debye-Hückel est plus grande que la maille du gel, les interactions électrostatiques directes sont négligeables et le gonflement est dû à la pression osmotique des contreions. La tension créée par cette pression est transmise par les noeuds du gel aux chaines élastiques qui se comportent comme des chaines isolées avec une force extérieure appliquée aux extrémités. Le facteur de structure du gel est la somme d'une composante gelée due aux hétérogénéités de concentration

  11. SURFACE DYNAMIC FRICTION OF POLYMER GELS

    J.P.Gong; G.Kagata; Y.Iwasaki; Y.Osada

    2000-01-01

    The sliding friction of various kinds of hydrogels has been studied and it was found that the frictional behaviors of the hydrogels do not conform to Amonton's law F =μW which well describes the friction of solids. The frictional force and its dependence on the load are quite different depending on the chemical structures of the gels, surface properties of the opposing substrates, and the measurement condition. The gel friction is explained in terms of interfacial interaction, either attractive or repulsive, between the polymer chain and the solid surface. According to this model, the friction is ascribed to the viscous flow of solvent at the interface in the repulsive case. In the attractive case, the force to detach the adsorbing chain from the substrate appears as friction. The surface adhesion between glass particles and gels measured by AFM showed a good correlation with the friction, which supported the repulsion-adsorption model proposed by the authors.

  12. Effect of Drug modification on properties of Ketoprofen Transdermal Gel

    Samy Ahmed

    2013-03-01

    Full Text Available The aim of this study was to develop Ketoprofen (KPF gel for tansdermal delivery that could enhance dissolution and permeability of KPFand to study the change in release and permeation of transdermal gel after formulating KPF as niosomes and solid dispersions. KPF gels were prepared using Carboxy methyl cellulose (CMC, hydroxyl propyl methyl cellulose (HPMC and methyl cellulose (MC with and without permeation enhancers (Tween 80 and Oleic acid. The effect of the polymers and permeation enhancers on the in vitro release and permeation was tested. The best formula was formulated as niosomal and solid dispersion gels. The effect of drug modification on the properties of KPF gel was examined. The results showed that both polymers and permeation enhancers affect release and permeation of KPF transdermal gel. The release and permeation from the niosomal gel were highly prolonged when compared to conventional gel .On the other hand, they were enhanced from the solid dispersion gel.

  13. Process for encapsulating active agents in gels

    Yilmaz, G.; Jongboom, R.O.J.; Oosterhaven, J.

    2001-01-01

    The present invention relates to a process for encapsulating an active agent in a biopolymer in the form of a gel, comprising the steps of: a) forming a dispersion or solution of the biopolymer in water; and b) adding the active agent to the dispersion or solution obtained in step a); wherein the biopolymer is at least partially dissolved before and/or after addition of the active agent. The gels obtained with the present invention are particularly suitable for coating or impregnating packagi...

  14. Alignment and nonlinear elasticity in biopolymer gels

    Feng, Jingchen; Levine, Herbert; Mao, Xiaoming; Sander, Leonard M.

    2015-04-01

    We present a Landau-type theory for the nonlinear elasticity of biopolymer gels with a part of the order parameter describing induced nematic order of fibers in the gel. We attribute the nonlinear elastic behavior of these materials to fiber alignment induced by strain. We suggest an application to contact guidance of cell motility in tissue. We compare our theory to simulation of a disordered lattice model for biopolymers. We treat homogeneous deformations such as simple shear, hydrostatic expansion, and simple extension, and obtain good agreement between theory and simulation. We also consider a localized perturbation which is a simple model for a contracting cell in a medium.

  15. Free forming of the gel by 3D gel printer SWIM-ER

    Okada, Koji; Tase, Taishi; Saito, Azusa; Makino, Masato; Gong, Jin; Kawakami, Masaru; Furukawa, Hidemitsu

    2015-04-01

    Gels, soft and wet materials, have unique properties such as material permeability, biocompatibility and low friction, which are hardly found in hard and dry materials. These superior characteristics of hydrogels promise to expand the medical applications. In recent years, the optical 3D gel printer named SWIM-ER (Soft and Wet Industrial - Easy Realizer) was developed by our team in order to fabricate tough gels with free form. We are aiming to create artificial blood vessel of the gel material by 3D gel printer. Artificial blood vessel is expected to be used for vascular surgery practice. The artificial blood vessel made by 3D gel printer can be create to free form on the basis of the biological data of the patient. Therefore, we believe it is possible to contribute to increasing the success rate and safety of vascular surgery by creating artificial blood vessel with 3D gel printer. The modeling method of SWIM-ER is as follow. Pregel solution is polymerized by one-point UV irradiation with optical fiber. The irradiation area is controlled by computer program, so that exact 3D free forming is realized. In this study, synthesis conditions are re-examined in order to improve the degree of freedom of fabrication. The dimensional accuracy in height direction is improved by increasing the cross linker concentration. We examined the relationship of resolution to the pitch and UV irradiation time in order to improve the modeling accuracy.

  16. Effect of gel matrix confinement on the solvent dynamics in supramolecular gels.

    Kowalczuk, Joanna; Rachocki, Adam; Bielejewski, Michał; Tritt-Goc, Jadwiga

    2016-06-15

    Supramolecular gels formed by the sugar gelator of methyl-4,6-O-(p-nitrobenzylidene)-α-d-glucopyranoside (1) with 1,3-propanediol (PG) and 1-butanol (BU) were prepared with different gelator concentrations. The solvent dynamics within gels, characterized by the diffusion coefficient (D) and the spin-lattice relaxation time (T1), was the subject of NMR diffusometry and relaxometry studies. The diffusion was studied as a function of diffusion time and gelator concentrations. The relaxation time was measured as a function of Larmor frequency. The decrease of the diffusion coefficient was observed as a function of diffusion time for both gels and for all studied gelator concentrations. It is indicative of the confinement effect due to the geometrical restrictions of the gel matrix. The relaxation data for PG solvent confined in 1/PG gel revealed the low frequency dispersion (in kHz region) which is a fingerprint of a specific interaction experienced by PG solvents in the presence of the rigid structure of gelator 1 aggregates. The relaxation model, well known from the interpretation of liquid confined in nanopores as reorientations mediated by translational displacements (RMTD), was successfully applied to analyze the data of studied solvents confined in matrices of supramolecular gels. The microstructures of gel matrices were imaged by Polarized Microscopy. PMID:27003500

  17. The mechanism and properties of acid-coagulated milk gels

    Chanokphat Phadungath

    2005-03-01

    Full Text Available Acid-coagulated milk products such as fresh acid-coagulated cheese varieties and yogurt areimportant dairy food products. However, little is known regarding the mechanisms involved in gel formation, physical properties of acid gels, and the effects of processing variables such as heat treatment and gelation temperature on the important physical properties of acid milk gels. This paper reviews the modern concepts of possible mechanisms involved in the formation of particle milk gel aggregation, along with recent developments including the use of techniques such as dynamic low amplitude oscillatory rheology to observe the gel formation process, and confocal laser scanning microscopy to monitor gel microstructure.

  18. Multiple-phase behavior and memory effect of polymer gel

    Annaka, M; Nakahira, T; Sugiyama, M; Hara, K; Matsuura, T

    2002-01-01

    A poly(4-acrylamidosalicylic acid) gel (PASA gel) exhibits multiple phases as characterized by distinct degrees of swelling; the gel can take one of four different swelling values, but none of the intermediate values. The gel has remarkable memory: the phase behavior of the gel depends on whether the gel has experienced the most swollen phase or the most collapsed phase in the immediate past. The information is stored and reversibly erased in the form of a macroscopic phase transition behavior. The structure factors corresponding to these four phases were obtained by SANS, which indicated the presence of characteristic structures depending on pH and temperature, particularly in the shrunken state. (orig.)

  19. Formation of macroporous gel morphology by phase separation in the silica sol-gel system containing nonionic surfactant

    Junsheng Wu; Xiaogang Li; Wei Du; Hua Chen

    2005-01-01

    The phase separation and gel formation behavior in an alkoxy-derived silica sol-gel system containing Ci6EOi5 has been investigated. Various gel morphologies similar to other sol-gel systems containing organic additives were obtained by changing the preparation conditions. Micrometer-range interconnected porous gels were obtained by freezing transitional structures of phase separation in the sol-gel process. The dependence of the resulting gel morphology on several important reaction parameters such as the starting composition, reaction temperature and acid catalyst concentration was studied in detail. The experimental results indicate that the gel morphology is mainly determined by the time relation between the onset of phase separation and gel formation.

  20. Synthesis of porphyrin-introduced silica gels by sol-gel process.

    Tanaka, Hidekazu; Yamada, Toshiyuki; Sugiyama, Shinichiro; Shiratori, Hideo; Hino, Ryozi

    2005-06-15

    Using a hydroxyl group appended free base porphyrin derivative (HP), porphyrin-introduced silica gels were synthesized by a sol-gel process. The HP content in the materials linearly increased with increasing the HP concentration. Meanwhile, free base tetraphenylporphyrin (TPP) with no hydroxyl groups were almost not incorporated into the silica gels. These facts suggested that the interaction between hydroxyl groups of the HP molecules and silica network is considerably strong. The UV-vis characters of HP-introduced materials were almost the same as pure HP molecules. The Beer's plot indicated that the HP molecules in the materials are dispersed. PMID:15897099

  1. Polyacrylamide gel polymerization with adjustable gelation rate

    Wiesner, Ivo; Wiesnerová, Dana

    2002-01-01

    Roč. 32, - (2002), s. 740-742. ISSN 0736-6205 R&D Projects: GA AV ČR KSK5052113; GA ČR GA521/00/0075 Keywords : polyacrylamide gel Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.173, year: 2002

  2. Polyacrylamide gel electrophoresis of soybean seed proteins

    W. Lassocińsk; J. S. Knypl

    2015-01-01

    Four major and 14 minor protein bands were detected when total salt soluble proteins of soybean (Glycine max cultivar Warszawska) seed were subjected to polyacrylamide gel electrophoresis under nondissociating conditions, and 16 protein bands were detected under dissociating conditions. Molecular weights of three major protein fractions in PAGE SDS were determined for around 18 500, 36 000 and 80 000 daltons.

  3. Calcium Impact on Milk Gels Formation

    Koutina, Glykeria

    of temperature and pH may result in different final structure properties in dairy products such as cheese. A significant amount of calcium remained in the micelles between pH 4.8 and 4.6, this can contribute to the final strength of acid milk gels, such as in yogurt or in cream cheeses. After the gelation point...

  4. Sol-gel Application in the Environment

    Kaštánek, František; Šolcová, Olga; Maléterová, Ywetta

    Maribor: Univerza v Mariboru, 2013. [Nanofuture. Maribor (SI), 03.02.2013-07.02.2013] R&D Projects: GA TA ČR TA01020804 Institutional support: RVO:67985858 Keywords : sol-gel methods * biosenzors * environment monitoring Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  5. Bioluminescent Bioreporters Encapsulated in Silica Gel

    Kuncová, Gabriela; Trögl, J.; Demnerová, K.; Ripp, S.; Sayler, G. S.

    -: -, 2008, O08-2 - 1-O08-2 - 4. [XVI International Conference on Bioencapsulation. Dublin (IE), 04.09.2008-06.09.2008] Institutional research plan: CEZ:AV0Z40720504 Keywords : bioluminescent bioreporter * silica gel * biosensor Subject RIV: CE - Biochemistry

  6. The repton model of gel electrophoresis

    Barkema, G. T.; Newman, M. E. J.

    1996-01-01

    We discuss the repton model of agarose gel electrophoresis of DNA. We review previous results, both analytic and numerical, as well as presenting a new numerical algorithm for the efficient simulation of the model, and suggesting a new approach to the model's analytic solution.

  7. Matching Two-dimensional Gel Electrophoresis' Spots

    Dos Anjos, António; AL-Tam, Faroq; Shahbazkia, Hamid Reza;

    2012-01-01

    This paper describes an approach for matching Two-Dimensional Electrophoresis (2-DE) gels' spots, involving the use of image registration. The number of false positive matches produced by the proposed approach is small, when compared to academic and commercial state-of-the-art approaches. This ar...

  8. Mechanical properties and morphology of polymer gels

    Sliozberg, Yelena; Sirk, Timothy; Brennan, John; Andzelm, Jan; Mrozek, Randy; Lenhart, Joseph

    2012-02-01

    Understanding morphology and mechanical response of polymeric gels is of particular importance to design materials with required energy dissipation characteristics. We will present our latest results for polymer gels based on 1) self-assembled block copolymers and 2) chemically cross-linked polymers. The dissipative particle dynamics (DPD) was used to predict morphology in good agreement with atomic force microscopy. We have performed DPD non-equilibrium oscillatory shear calculations predicting elastic modulus of unentangled gels that correlates well with experimental rheology data. However, this methodology fails to predict mechanics of entangled polymer networks due to unphysical chain crossing brought by the soft potentials used in DPD simulations. Recently, we have introduced an improved segmental repulsion potential that removes the bond crossing allowing for reptation dynamics. The improved DPD method was used in simulations for entangled gels to explore impact of branched architecture of solvent on the mechanical response to the tensile deformation. Novel architectures of solvent resulting in a dramatic increase of the elastic modulus were identified. The topological analysis was applied to understand contributions of chemical cross-links and entanglements to the stress.

  9. The charge transport in polymeric gel electrolytes

    Reiche, A

    2001-01-01

    The aim of the present thesis consisted in the study of the charge transport in gel electrolytes, which were obtained by photopolymerization of oligo(ethylene glycol) sub n -dimethacrylates with n=3, 9, and 23, and the survey of structure and property relations for the optimization of the electrolyte composition. The pressure dependence of the electric conductivity was measured. (HSI)

  10. Ordering phenomena in ABA triblock copolymer gels

    Reynders, K.; Mischenko, N.; Kleppinger, R.; Reynaers, H.; Koch, M.H.J.; Mortensen, K.

    1997-01-01

    Temperature and concentration dependencies of the degree of order in ABA triblock copolymer gels are discussed. Two factors can influence the ordering phenomena: the conformation of the midblocks (links of the network) and the polydispersity of the endblock domains (nodes of the network). The...

  11. Simple Cloud Chambers Using Gel Ice Packs

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  12. Effectiveness of Gel Repellents on Feral Pigeons

    Birte Stock

    2013-12-01

    Full Text Available Millions of feral pigeons (Columba livia live in close association with the human population in our cities. They pose serious health risks to humans and lead to high economic loss due to damage caused to buildings. Consequently, house owners and city authorities are not willing to allow pigeons on their buildings. While various avian repellents are regularly introduced onto the market, scientific proof of efficacy is lacking. This study aimed at testing the effectiveness of two avian gel repellents and additionally examined their application from animal welfare standpoint. The gels used an alleged tactile or visual aversion of the birds, reinforced by additional sensory cues. We mounted experimental shelves with the installed repellents in a pigeon loft and observed the behavior of free-living feral pigeons towards the systems. Both gels showed a restricted, transient repellent effect, but failed to prove the claimed complete effectiveness. Additionally, the gels’ adhesive effect remains doubtful in view of animal welfare because gluing of plumage presents a risk to feral pigeons and also to other non-target birds. This study infers that both gels lack the promised complete efficacy, conflict with animal welfare concerns and are therefore not suitable for feral pigeon management in urban areas.

  13. Growth of hydroxyapatite nanoparticles on silica gels.

    Rivera-Muñoz, E M; Huirache-Acuña, R; Velázquez, R; Alonso-Núñez, G; Eguía-Eguía, S

    2011-06-01

    Synthetic, hydroxyapatite nanoparticles were grown on the surface of silica gels. The synthesis of those nanoparticles was obtained by immersing silica gels in a simulated body fluid (SBF) at 37 degrees C. The SBF was replaced every week to keep constant the Ca and P ion concentration and subsequent growth of hydroxyapatite was evaluated after 1-6 weeks of total soaking time in SBF. Hydroxyapatite nanoparticles were observed by scanning electron microscopy (SEM) on the surface of silica gel samples and confirmed by energy dispersive X-ray spectroscopy (EDS), Fourier Transform Infra Red Spectroscopy (FTIR) and powder X-ray Diffractometry (XRD) analysis. These particles show a regular shape and uniform size every week, keeping within the nanoscale always. Both the size and morphology of hydroxyapatite nanoparticles obtained are the result of the use of different chemical additives in the synthesis of silica gels, since they affect the liquid-to-solid interface, and the growth could correspond to a diffusion limited aggregation (DLA) process. A more detailed analysis, with higher magnifications, showed that hydroxyapatite nanoparticles are not solid spheres, showing a branched texture and their size depends on the scale and resolution of the measure instrument. PMID:21770224

  14. Screening of mucoadhesive vaginal gel formulations

    Ana Ochoa Andrade

    2014-12-01

    Full Text Available Rational design of vaginal drug delivery formulations requires special attention to vehicle properties that optimize vaginal coating and retention. The aim of the present work was to perform a screening of mucoadhesive vaginal gels formulated with carbomer or carrageenan in binary combination with a second polymer (carbomer, guar or xanthan gum. The gels were characterised using in vitroadhesion, spreadability and leakage potential studies, as well as rheological measurements (stress and frequency sweep tests and the effect of dilution with simulated vaginal fluid (SVF on spreadability. Results were analysed using analysis of variance and multiple factor analysis. The combination of polymers enhanced adhesion of both primary gelling agents, carbomer and carrageenan. From the rheological point of view all formulations presented a similar behaviour, prevalently elastic and characterised by loss tangent values well below 1. No correlation between rheological and adhesion behaviour was found. Carbomer and carrageenan gels containing the highest percentage of xanthan gum displayed good in vitro mucoadhesion and spreadability, minimal leakage potential and high resistance to dilution. The positive results obtained with carrageenan-xanthan gum-based gels can encourage the use of natural biocompatible adjuvants in the composition of vaginal products, a formulation field that is currently under the synthetic domain.

  15. 3D gel printing for soft-matter systems innovation

    Furukawa, Hidemitsu; Kawakami, Masaru; Gong, Jin; Makino, Masato; Kabir, M. Hasnat; Saito, Azusa

    2015-04-01

    In the past decade, several high-strength gels have been developed, especially from Japan. These gels are expected to use as a kind of new engineering materials in the fields of industry and medical as substitutes to polyester fibers, which are materials of artificial blood vessels. We consider if various gel materials including such high-strength gels are 3D-printable, many new soft and wet systems will be developed since the most intricate shape gels can be printed regardless of the quite softness and brittleness of gels. Recently we have tried to develop an optical 3D gel printer to realize the free-form formation of gel materials. We named this apparatus Easy Realizer of Soft and Wet Industrial Materials (SWIM-ER). The SWIM-ER will be applied to print bespoke artificial organs, including artificial blood vessels, which will be possibly used for both surgery trainings and actual surgery. The SWIM-ER can print one of the world strongest gels, called Double-Network (DN) gels, by using UV irradiation through an optical fiber. Now we also are developing another type of 3D gel printer for foods, named E-Chef. We believe these new 3D gel printers will broaden the applications of soft-matter gels.

  16. Disulfide-Functionalized Diblock Copolymer Worm Gels.

    Warren, Nicholas J; Rosselgong, Julien; Madsen, Jeppe; Armes, Steven P

    2015-08-10

    Two strategies for introducing disulfide groups at the outer surface of RAFT-synthesized poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) (PGMA-PHPMA, or Gx-Hy for brevity) diblock copolymer worms are investigated. The first approach involved statistical copolymerization of GMA with a small amount of disulfide dimethacrylate (DSDMA, or D) comonomer to afford a G54-D0.50 macromolecular chain transfer agent (macro-CTA); this synthesis was conducted in relatively dilute solution in order to ensure mainly intramolecular cyclization and hence the formation of linear chains. Alternatively, a new disulfide-based bifunctional RAFT agent (DSDB) was used to prepare a G45-S-S-G45 (or (G45-S)2) macro-CTA. A binary mixture of a non-functionalized G55 macro-CTA was utilized with each of these two disulfide-based macro-CTAs in turn for the RAFT aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA). By targeting a PHPMA DP of 130 and systematically varying the molar ratio of the two macro-CTAs, a series of disulfide-functionalized diblock copolymer worm gels were obtained. For both formulations, oscillatory rheology studies confirmed that higher disulfide contents led to stronger gels, presumably as a result of inter-worm covalent bond formation via disulfide/thiol exchange. Using the DSDB-based macro-CTA led to the strongest worm gels, and this formulation also proved to be more effective in suppressing the thermosensitive behavior that is observed for the nondisulfide-functionalized control worm gel. However, macroscopic precipitation occurred when the proportion of DSDB-based macro-CTA was increased to 50 mol %, whereas the DSDMA-based macro-CTA could be utilized at up to 80 mol %. Finally, the worm gel modulus could be reduced to that of a nondisulfide-containing worm gel by reductive cleavage of the inter-worm disulfide bonds using excess tris(2-carboxyethyl)phosphine (TCEP) to yield thiol groups. These new biomimetic worm gels are

  17. Diffusion measurement in ferrous infused gel dosimeters

    Background: The compositions of Ferrous sulphate, Agarose and Xylenol orange dye and Ferrous sulphate, Gelatin and Xylenol orange dye in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. Ionizing radiation causes oxidation of Fe2+ ion to Fe3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours after irradiation. Materials and methods: 25 m M sulphuric acid, 0.4 mm ferrous ammonium sulphate, 0.2 mm xylenol orange dye and 1% by weight agarose in distilled water named Agarose and Xylenol orange dye and 0.1 mm ferrous ammonium sulphate, 0.1 mm xylenol orange dye, 50 mm sulphuric acid and 5% by weight gelatin in distilled water named Gelatin and Xylenol orange dye are used as two gel dosimeters. All chemicals were supplied by Sigma Ald ridge Company, Germany. The gels were poured in Perspex casts and were irradiated to a beam of X ray from linear accelerators or X ray machine. Results: In this study diffusion coefficients of Agarose and Xylenol orange dye and Gelatin and Xylenol orange dye dosimeters have been measured through a computer program for different temperature. The ferric ion diffusion coefficient (D) for the Agarose and Xylenol orange dye and Gelatin and Xylenol orange dye dosimeters were measured as (1.19.±0.03) x 10-2 cm2.hr -1 and (0.83±0.03) x 10-2 cm2.hr-1 respectively at room temperature. Conclusion: For both dosimeters the diffusion coefficients decreased with gel storage temperatures down to 6 digC. Gelatin and Xylenol orange dye dosimeters have advantage of lower diffusion coefficient for a specified temperature

  18. Ultraviolet absorption detection of DNA in gels

    A method and apparatus for the detection and quantification of large fragments of unlabelled deoxyribonucleic acid (DNA) in agarose gels is presented. The technique is based on ultra-violet (UV) absorption by nucleotides. A deuterium lamp was used to illuminate regions of an electrophoresis gel. As DNA bands passed through the illuminated region of the gel the amount of UV light transmitted was reduced due to DNA absorption. Two detection systems were investigated. In the first system, synthetic chemical vapour deposition (CVD) diamond strip detectors were used to locate regions of DNA in the gels by detecting the transmitted light. CVD diamond has a high indirect band gap of 5.45 eV and is therefore sensitive to UV photons of wavelengths < 224 nm. A number of CVD diamond samples were characterised to investigate their suitability as detectors for this application. The detectors' quantum efficiency, UV response and time response were measured. DNA bands containing as little as 20 ng were detected by the diamond. In a second system, a deuterium lamp was used to illuminate individual sample lanes of an electrophoresis gel via an array of optical fibres. During electrophoresis the regions of DNA were detected with illumination at 260 nm, using a UV-sensitive charge coupled device (CCD). As the absorption coefficient of a DNA sample is approximately proportional to its mass, the technique is inherently quantitative. This system had a detection limit of 0.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. Using this detection technique, the DNA sample remains in its native state. The removal of carcinogenic dyes from the detection procedure greatly reduces associated biological hazards. (author)

  19. Sol-Gel Synthesis of Au-Nanoparticle Dispersed Bicontinuous Macroporous Siloxane Gel

    Hamada, Y; Nishi, M; Shimotsuma, Y; Miura, K; Hirao, K, E-mail: west@collon1.kuic.kyoto-u.ac.jp [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2011-10-29

    We synthesized Au-nanoparticle dispersed siloxane gel with well-defined bicontinuous macroporous morphologies. We employed methyltrimethoxysilane (MTMS) as a precursor of the gel skeleton, and also employed hydrogen tetrachloroaurate(III) as both a precursor of Au nanoparticles and an acid catalyst for hydrolysis/condensation of methoxysilanes. The effect of adding (3-mercaptopropyl)trimethoxysilane (MPTMS) as a starting material on the obtained structure was also investigated. It is found that Au nanoparticles of 20-30 nm in grain size are uniformly dispersed on the gel surface in the system containing MPTMS; in contrast, Au nanoparticles assembled in the pits in the MPTMS-free system. All the heat-treated MPTMS-containing gels showed surface plasmon absorption, and the peaks shifted from 550 to 520 nm with increasing the calcination temperature.

  20. X-ray computed tomography of gel dosimeters: characterization of gels

    Full text: A recent study has shown that polymer gel dosimeters can successfully be imaged using X-ray CT. As an imaging method. X-ray CT has been shown to be fast, relatively temperature insensitive, and does not suffer from image non uniformities to the extent which can occur with magnetic resonance imaging (MRI). This paper examines the dose response of various polyacrylamide gel (PAG) dosimeter compositions and presents an empirical model relating dosimeter sensitivity and CT number (H) to the composition of the polymer gel dosimeter. Polymer gels were manufactured with varying concentrations of acrylamide and N,N'- methylene-bis-acrylamide monomers, gelatin and water. The gels were stored in 25 ml plastic VapexTM vials and sealed in BarexTM pouches to prevent oxygen contamination through the plastic walls of the vials. The gels were irradiated within 2 hours of manufacture, exposed to oxygen 2 days later, and then left for 2 days prior to imaging. To image the gels the highest kV setting of the scanner was used together with the highest mAs available for that kV. Total imaging time was less than 5 minutes and 20 slices per image were taken. The dose sensitivity was found to be 0.23m H.Gy-1, where m is the concentration of each monomer by percentage weight. The linear dose range was 0-10 Gy for all compositions. A qualitative examination of the dose resolution, i.e. the ability to resolve the measured absorbed doses to a certain level of confidence, was improved with increasing sensitivity of the gels. However, this was subject to many factors such as machine settings and phantom width. The composition of PAG dosimeters can be optimised for evaluation using x-ray CT and this was found to improve the quality of the method significantly. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  1. Gel2DE - A software tool for correlation analysis of 2D gel electrophoresis data

    Øye, Ola Kristoffer; Jørgensen, Katarina Mariann; Hjelle, Sigrun Margrethe; Sulen, André; Ulvang, Dag Magne; Gjertsen, Bjørn Tore

    2013-01-01

    Background: Two-dimensional gel electrophoresis (2DE) is a powerful technique for studying protein isoforms and their modifications. Existing commercial 2D image analysis tools rely on spot detection that limits analysis of complex protein profiles, e.g. spot appearance/disappearance or overlapping spots. Pixel-by-pixel correlation analysis, an analysis technique for identifying relations between protein patterns in gel images and external variables, can overcome such limitations ...

  2. Gel polymer electrolytes based on PMMA III. PMMA gels containing cadmium

    Vondrák, Jiří; Sedlaříková, M.; Velická, Jana; Klápště, Břetislav; Novák, V.; Reiter, Jakub

    2003-01-01

    Roč. 48, č. 8 (2003), s. 1001-1004. ISSN 0013-4686 R&D Projects: GA AV ČR IAA4032002; GA ČR GA104/02/0731; GA MŠk ME 216 Institutional research plan: CEZ:AV0Z4032918; CEZ:MSM 262200010 Keywords : gel polymer electrolytes * polymethylmethacrylate * cadmium gel electrolyte Subject RIV: CA - Inorganic Chemistry Impact factor: 1.996, year: 2003

  3. On the Structure and Dynamics of Polyelectrolyte Gel Systems and Gel-surfactant Complexes

    Råsmark, Per Johan

    2004-01-01

    This thesis describes the results of experimental work on polyelectrolyte gels and their interaction with oppositely charged surfactants, and presents two new algorithms applicable to the simulation of colloid and polymer systems. The model systems investigated were crosslinked poly(acrylate) (PA) and poly(styrene sulphonate) (PSS), and the surfactant was dodecyl trimethylammonium bromide (DoTAB). Pure gel materials were studied using dynamic light scattering. It was shown that the diffusion ...

  4. Accumulation of humic acid in DET/DGT gels

    Van der Veeken, P.L.R.; Chakraborty, P.; Van Leeuwen, H.P.

    Gel layer based sensors are increasingly employed for dynamic trace metal speciation analysis in aquatic and soil media. In DGT (Diffusive Gradient in Thin film), polyacrylamide hydrogels are commonly used for the diffusive gel layer. While some...

  5. Covalent Fusion of layered Incompatible Gels in Immiscible Solvents

    Biswas, Santidan; Singh, Awaneesh; Matyjaszewski, Krzysztof; Balazs, Anna C.

    We carry out dissipative particle dynamics (DPD) simulations to model a two layered stackable gel where the gels are incompatible and are present in immiscible solvent. The bottom layer of the gel is created first and then a solution of new initiators, monomers and cross-linkers is introduced on top of it. These components then undergo polymerization and form the second gel layer. We study all possible combinations of free radical polymerization (FRP) and atom transfer radical polymerization (ATRP) mechanisms with the two layers of the gel. For example, the bottom layer gel is created via ATRP, whereas the top layer gel follows FRP. Our focus is to do a systematic study of all these combinations and find out the factors responsible for combining two incompatible gels in immiscible solvents.

  6. Silicone Gel-Filled Breast Implants: Updated Safety Information

    ... Products For Consumers Home For Consumers Consumer Updates Silicone Gel-Filled Breast Implants: Updated Safety Information Share ... Español When the Food and Drug Administration allowed silicone gel-filled breast implants back on the market ...

  7. Monolithic diphasic gels of mullite by sol-gel process under ultrasound stimulation.

    Vollet, D R; Donatti, D A; Domingos, R N; de Oliveira, I

    1998-06-01

    Diphasic gel in the mullite composition was prepared from a colloidal sol of boehmite mixed with a hydrolyzed tetraethoxisilane (TEOS) solution. The boehmite sol was obtained by peptization of a poorly crystallized or very small mean crystallite size (approximately 34 A) precipitate, resulting from the reaction between solutions of aluminum sulfate and sodium hydroxide. Ultrasound was utilized in the processes of the TEOS hydrolysis and the boehmite peptization, and also for complete homogenization of the mixture to gel. The wet gel is almost clear and monolithic. The gel transparency is lost on drying, when syneresis has ended, so that the interlinked pore structure starts to empty and is recovered upon water re-absorption. Cracking closely accompanies this critical drying process. Differential thermal analysis (DTA) and X-ray diffraction (XRD) show that the solid structure of the gel is composed of an amorphous silica phase, as a matrix, and a colloidal sized crystalline phase of boehmite. Upon heat treatment, the boehmite phase within the gel closely follows the same transition sequence as in pure alumina shifted towards higher temperatures. Orthorhombic mullite formation was detected at 1300 degrees C. PMID:11270341

  8. Study of nuclear glasses alteration gel and synthesis of some model gels

    This work deals with the general problem of alteration of the reference nuclear glass R7T7. Attention is paid particularly to the altered layer formed at the glass surface during alteration process. In opposition to previous works, related essentially to glass dissolution kinetics based on chemical analyses of lixiviated elements, this thesis deals with alteration problems through structural studies of the reference glass and derived gel. This approach allows the determination of mechanisms for the gel formation and a better understanding of the behaviour of glasses towards lixiviation. Both approaches appeared complementary. Based on several spectroscopic techniques, this work showed the particular role of cations such as calcium, zirconium and iron. Studies of silica-based synthetic gels showed the synergic effect of formers cation and of one highly coordinated cation. The variation of the wavenumber related to Si-O-Si asymmetric stretching vibration can be correlated to O/Si ratio for ternary systems Si/Na/Zr. On the contrary, the Si losses of the materials depend on the number of non-bridging oxygen atoms. In the perspective of long-term behaviour, the alteration gel presents better characteristics than initial glass. It is therefore a highly stable material in static conditions. In the same way, synthetic gels are materials with very low solubilities (much lower than the alteration gel) and could be used as confining matrices. (authors). refs., 71 figs., 37 tabs

  9. Relationship between texture of gels and flavour release

    Koliandris, Andreas

    2009-01-01

    To provide further insight into the relationship between the structure of hydrocolloid solutions and gels and perception of taste and flavour, solutions of gelatin and locust bean gum, and gels prepared from mixtures of (a) high acyl and low acyl gellan (b) carrageenan and locust bean gum were studied. Both solutions contained sodium chloride and the gels were flavoured with ethyl butyrate. The gels were classified from rheological measurements into 3 categories: strong/brittle, intermedi...

  10. Comparison Between the Elasticity of Polyacrylamide and Polyacrylic Gels

    Benguigui, L.

    1995-01-01

    We measured the Young modulus E of polyacrylamide and polyacrylic gels as a function of the crosslink and polymer concentrations. We found that the variation of E with these two parameters is completely different for the two kinds of gels. For the polyacrylic gels, E is an increasing function of the crosslink and polymer concentrations. However, in the case of the polyacrylamide gels, E increases with polymer concentration but not always with the crosslink concentration. For low polymer conce...

  11. Gel Mobility Shift Assays to Detect Protein–RNA Interactions

    Yakhnin, Alexander V.; Yakhnin, Helen; Babitzke, Paul

    2012-01-01

    The gel mobility shift assay is a powerful technique for detecting and quantifying protein–RNA interactions. While other techniques such as filter binding and isothermal titration calorimetry (ITC) are available for quantifying protein–RNA interactions, gel shift analysis provides the added advantage that you can visualize the protein–RNA complexes. In the gel shift assay, protein–RNA complexes are typically separated from the unbound RNA using native polyacrylamide gels in Tris/borate/EDTA b...

  12. Sol-gel Technology for Sensor Applications (Review Paper)

    Chaudhury, N. K.; R. Gupta; S Gulia

    2007-01-01

    Sol-gel processes refer to the transition of predefined compositions of inorganic alkoxidesprecursors from liquid sol phase to solid gel phase. The phenomenon of sol-gel was known tomankind for more than 150 years. It is because of concerted efforts of researchers frommultidisciplinary fields, sol-gel science transformed to technology. Several products are alreadycommercially available for applications in optical coatings, nanocomposites, and public healthcare.Potential applications in the ar...

  13. Gel dosimetry for HDR Brachytherapy 3-D distribution through MRI

    Gel dosimetry using MRI is increasingly being utilized in contemporary literature. In our work we investigated the calibration of an acrylic gel by means of imaging with magnetic resonance and its application to the dose measurement in a 3D distribution 192Ir HDR brachytherapy treatment. Early gel dosimetry used Fricke gels and T1 relaxation time. In 2001 Fong et al. introduced a new normoxic gel known as ''MAGIC'' gel, the main components of which are Metacrylic Acid (polymer) and Hydroquinone ( polymerizing inhibitor). For this material, the evidence of radiation dose is indicated by a change in the T2 relaxation time on an MR image. Later studies varied concentrations of the MAGIC gel components in order to observe its effect and the behavior of the gel sensitivity, for magnetic fields over 0.5 T. In the 1980s a series of studies on dose quantification using magnetic resonance images and Fricke gels were performed by evaluating T1 signal through means of an Inversion Recovery technique. Polymer gels have been developed to avoid the adverse effects of oxygen that plague Fricke gels. Normoxic gels have a component which helps to capture the oxygen dissolved in the gel (MAGIC). For these type of gels, measurements of T2 are made using a Spin-Echo technique. For both groups of gels, the Relaxativity compared to either T1 or T2 varies linearly with the absorbed dose. Novotny et al. has obtained a dose response curve for BANG-2 gel showing a linear relationship of 1/T2 vs D[Gy]. In the work presented here we tested and found the same linear relation between spin-spin relaxation (R2=1/T2) versus dose up to 8.0Gy

  14. Methods of Manufacturing Bioactive Gels from Extracellular Matrix Material

    Kentner, Kimberly A. (Inventor); Stuart, Katherine A. (Inventor); Janis, Abram D. (Inventor)

    2016-01-01

    The present invention is directed to methods of manufacturing bioactive gels from ECM material, i.e., gels which retain bioactivity, and can serve as scaffolds for preclinical and clinical tissue engineering and regenerative medicine approaches to tissue reconstruction. The manufacturing methods take advantage of a new recognition that bioactive gels from ECM material can be created by digesting particularized ECM material in an alkaline environment and neutralizing to provide bioactive gels.

  15. CURRENT COLLOIDAL DISPERSION GELS ARE NOT SUPERIOR TO POLYMER FLOODING

    Seright Randy; Han Peihui; Wang Dongmei

    2006-01-01

    The suggestion that the colloidal-dispersion-gel (CDG) process is superior to normal polymer flooding is misleading and generally incorrect. Colloidal dispersion gels, in their present state of technological development, should not be advocated as an improvement to, or substitute for, polymer flooding. Gels made from aluminum-citrate crosslinked polyacrylamides can act as conventional gels and provide effective conformance improvement in treating some types of excess water production problems if sound scientific and engineering principles are respected.

  16. Polymer gel dosimetry system for radiation therapy

    Purpose/Objective: Recently developed treatment modalities such as stereotactic and conformal radiation therapy produce complex dose distributions which are difficult or impractical to measure with conventional dosimetry instrumentation. Three-dimensional treatment planning systems which purport to calculate these complex dose distributions should be compared to experimental results before being routinely applied to clinical problems. There is a need for a new class of tissue-equivalent dosimeters capable of providing accurate, high resolution, time-integrated and three dimensional dose distributions. The recently developed BANG polymer gel dosimetry system (MGS Research, Inc., Guilford, CT) is ideally suited for the task described above. Physico-chemical principles of the polymer gel dosimetry are presented, together with examples of its application to radiation therapy. Data analysis and display program, written for Macintosh computer, is demonstrated. Materials and Methods: Radiation-induced polymerization of acrylic monomers, which are dispersed in tissue-equivalent gelatin, has been shown to be dependent on the dose, but independent of the dose rate or photon energy. Therefore, the spatial distribution of polymer in the gel is precisely representative of the dose distribution. As the polymeric microparticles reduce the water proton NMR relaxation times in the gel, the dose distribution can be measured with high resolution and accuracy using magnetic resonance imaging. Also, as these microparticles cannot diffuse through the gelatin matrix, their distribution is permanent. An improved formulation of the BANG dosimeter consists of 3% w/v acrylic acid, 3% N,N'-methylene-bis-acrylamide, 1% sodium hydroxide, 5% gelatin, and 88% water. MR images are transferred via a local network to a Macintosh computer, and R2 maps constructed on the basis of multiple TE images, using a non-linear least squares fit based on the Levenberg-Marquardt algorithm. A dose-to-R2

  17. Formulation and method for preparing gels comprising hydrous aluminum oxide

    Collins, Jack L.

    2014-06-17

    Formulations useful for preparing hydrous aluminum oxide gels contain a metal salt including aluminum, an organic base, and a complexing agent. Methods for preparing gels containing hydrous aluminum oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including aluminum, an organic base, and a complexing agent.

  18. 21 CFR 520.1453 - Moxidectin and praziquantel gel.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Moxidectin and praziquantel gel. 520.1453 Section... and praziquantel gel. (a) Specifications. Each milliliter of gel contains 20 milligrams (mg) (2.0 percent) moxidectin and 125 mg (12.5 percent) praziquantel. (b) Sponsor. See No. 000856 in § 510.600(c)...

  19. Modification of gel architecture and TBE/TAE buffer composition to minimize heating during agarose gel electrophoresis

    Sanderson, Brian A.; Araki, Naoko; Lilley, Jennifer L.; Guerrero, Gilberto; Lewis, L. Kevin

    2014-01-01

    Agarose gel electrophoresis of DNA and RNA is routinely performed using buffers containing either Tris, acetate and EDTA (TAE) or Tris, borate and EDTA (TBE). Gels are run at a low, constant voltage (~ 10 V/cm) to minimize current and asymmetric heating effects, which can induce band artifacts and poor resolution. In this study, alterations of gel structure and conductive media composition were analyzed to identify factors causing higher electrical currents during horizontal slab gel electrop...

  20. Carbon Redox-Polymer-Gel Hybrid Supercapacitors

    Vlad, A.; Singh, N.; Melinte, S.; Gohy, J.-F.; Ajayan, P. M.

    2016-02-01

    Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances.

  1. Optical-CT scanning of polymer gels

    The application of optical-CT scanning to achieve accurate high-resolution 3D dosimetry is a subject of current interest. The purpose of this paper is to provide a brief overview of past research and achievements in optical-CT polymer gel dosimetry, and to review current issues and challenges. The origins of optical-CT imaging of light-scattering polymer gels are reviewed. Techniques to characterize and optimize optical-CT performance are presented. Particular attention is given to studies of artifacts in optical-CT imaging, an important area that has not been well studied to date. The technique of optical-CT simulation by Monte-Carlo modeling is introduced as a tool to explore such artifacts. New simulation studies are presented and compared with experimental data

  2. Comparative proteomics and difference gel electrophoresis.

    Minden, Jonathan

    2007-12-01

    The goal of comparative proteomics is to analyze proteome changes in response to development, disease, or environment. This is a two-step process in which proteins within cellular extracts are first fractionated to reduce sample complexity, and then the proteins are identified by mass spectrometry. Two-dimensional electrophoresis (2DE) is the long-time standard for protein separation, but it has suffered from poor reproducibility and limited sensitivity. Difference gel electrophoresis (DIGE), in which two protein samples are separately labeled with different fluorescent dyes and then co-electrophoresed on the same 2DE gel, was developed to overcome the reproducibility and sensitivity limitations. In this essay, I discuss the principles of comparative proteomics and the development of DIGE. PMID:18251249

  3. Sol-gel preparation of ceramic fuel

    The principle is described of a method based on the homogeneous hydrolysis of a uranyl nitrate solution in the presence of urea and urotropin. The procedure is given and the equipment described for the production of particles having 0.5 to 4.0 mm in dia. The gelation column (capacity 1.5 kg of gel U/hour) consists of a glass tube 50 mm in dia and 2,000 mm in length through which ascends hot oil. The finished gel is washed in ammonia water, dried, calcinated and reduced in a N2+6%H2 atmosphere. Sintering of the undamaged microspheres is carried out at temperatures between 1,200 to 1,500 degC. (M.K.)

  4. Ceramica sphere production by a gel casting

    The technology of (Th,U)O2 microspheres production by gel casting and subsequente thermal treatment has been transferred from NUKEM GmbH assisted by Kraftwerk Union A.G., both West Germany, to NUCLEBRAS, where it was jointly adapted to produce microspheres suitable for pressing. As a result, there are now available various possibilities to produce ceramic spheres with different characteristics that can be used in different applications. Examples of these characteristics are the range of gel sphere diameters (200 to 5000 μmm) and the value of the specific surface (about 50m2/g for calcined (Th, U)O2 and potentially higher than m2/g for other ceramic materials) (Author)

  5. 3D dosimetry fundamentals: gels and plastics

    Lepage, M.; Jordan, K.

    2010-11-01

    Many different materials have been developed for 3D radiation dosimetry since the Fricke gel dosimeter was first proposed in 1984. This paper is intended as an entry point into these materials where we provide an overview of the basic principles for the most explored materials. References to appropriate sources are provided such that the reader interested in more details can quickly find relevant information.

  6. Diffusion of polyelectrolytes in polyelectrolyte gels

    Rahalkar, Anand; Muthukumar, Murugappan

    2015-03-01

    Using dynamic light scattering, we have investigated the diffusion coefficient of sodium poly(styrene sulfonate) in a matrix of poly(acrylamide-co-acrylate) gels. The diffusion coefficient of the probe polyelectrolyte exhibits a crossover behavior from a particle-diffusion to entropic-barrier dominated diffusion, as the molecular weight is increased. The effect of electrostatics, by varying the charge density of the matrix, on probe diffusion constant will be presented.

  7. Gel Polymer Electrolytes Based on PMMA

    Vondrák, Jiří; Klápště, Břetislav; Velická, Jana; Reiter, Jakub

    Vol. 1. Brno: Akademické nakladatelství CERM, 2000 - (Vondrák, J.; Sedlaříková, M.), s. 1.1-1.4 ISBN 80-214-1614-9. [Advanced Batteries and Accumulators /1./. Brno (CZ), 28.08.2000-01.09.2000] R&D Projects: GA AV ČR IAA4032002; GA MŠk ME 216 Institutional research plan: CEZ:AV0Z4032918 Keywords : PMMA * gel * electrolytes Subject RIV: CG - Electrochemistry

  8. Rheology of Biopolymer Solutions and Gels

    David R. Picout

    2003-01-01

    Full Text Available Rheological techniques and methods have been employed for many decades in the characterization of polymers. Originally developed and used on synthetic polymers, rheology has then found much interest in the field of natural (bio polymers. This review concentrates on introducing the fundamentals of rheology and on discussing the rheological aspects and properties of the two major classes of biopolymers: polysaccharides and proteins. An overview of both their solution properties (dilute to semi-dilute and gel properties is described.

  9. Il Gel Piastrinico in chirurgia orale

    Sacchi M.C.

    2012-01-01

    Obiettivi: L’utilizzo topico di emocomponenti autologhi, il concentrato piastrinico (CP) ed il plasma povero di piastrine, rappresenta una delle strategie più innovative per modulare ed amplificare i processi di guarigione e di rigenerazione tessutale. Con questo studio si è dimostrato che l’applicazione del gel piastrinico, quando viene applicato in chirurgia orale ed in particolare nell’implantologia, è in grado di migliorare ed accelerare i processi osteogenetici;Metodologia: il CP, prepar...

  10. Effectiveness of Gel Repellents on Feral Pigeons

    Birte Stock; Daniel Haag-Wackernagel

    2013-01-01

    Simple Summary Feral pigeons live in close association in urban areas. They constitute serious health risks to humans and also lead to high economic loss due to costly damage to buildings, historic monuments, statues and even vegetation. While numerous avian repellent systems are regularly introduced onto the market, scientific proof of efficacy and their use from the point of view of animal welfare is lacking. Therefore, two avian gel repellents were studied on free-living feral pigeons in t...

  11. Sol-gel processes in catalysis

    Volovych, Iryna

    2014-01-01

    Palladium-, Rhodium- und Mangankatalysatoren wurden auf hydrophil und hydrophob modifizierten Silika mittels der Sol-Gel Methode immobilisiert und in einer Vielfalt von Reaktionen in wässrigen Lösungen angewendet. In diesem Zusammenhang wurden umweltfreundlichere und kostensparendere Konzepte zur Reaktionsführung entwickelt. Einerseits wurden tensidhaltige wässrige Lösungen mit organischen Zusatzstoffen eingesetzt, welche eine grüne Alternative zu konventionellen Lösungsmittelsystemen darstel...

  12. Silver staining of proteins in polyacrylamide gels

    Chevallet, Mireille; Luche, Sylvie; Rabilloud, Thierry

    2006-01-01

    International audience Silver staining is used to detect proteins after electrophoretic separation on polyacrylamide gels. It combines excellent sensitivity (in the low nanogram range) with the use of very simple and cheap equipment and chemicals. It is compatible with downstream processing, such as mass spectrometry analysis after protein digestion. The sequential phases of silver staining are protein fixation, then sensitization, then silver impregnation and finally image development. Se...

  13. Exploratory data analysis groupware for qualitative and quantitative electrophoretic gel analysis over the Internet-WebGel.

    Lemkin, P F; Myrick, J M; Lakshmanan, Y; Shue, M J; Patrick, J L; Hornbeck, P V; Thornwal, G C; Partin, A W

    1999-12-01

    Many scientists use quantitative measurements to compare the presence and amount, of various proteins and nucleotides among series of one- and two-dimensional (1-D and 2-D) electrophoretic gels. These gels are often scanned into digital image files. Gel spots are then quantified using stand-alone analysis software. However, as more research collaborations take place over the Internet, it has become useful to share intermediate quantitative data between researchers. This allows research group members to investigate their data and share their work in progress. We developed a World Wide Web group-accessible software system, WebGel, for interactively exploring qualitative and quantitative differences between electrophoretic gels. Such Internet databases are useful for publishing quantitative data and allow other researchers to explore the data with respect to their own research. Because intermediate results of one user may be shared with their collaborators using WebGel, this form of active data-sharing constitutes a groupware method for enhancing collaborative research. Quantitative and image gel data from a stand-alone gel image processing system are copied to a database accessible on the WebGel Web server. These data are then available for analysis by the WebGel database program residing on that server. Visualization is critical for better understanding of the data. WebGel helps organize labeled gel images into montages of corresponding spots as seen in these different gels. Various views of multiple gel images, including sets of spots, normalization spots, labeled spots, segmented gels, etc. may also be displayed. These displays are active and may be used for performing database operations directly on individual protein spots by simply clicking on them. Corresponding regions between sets of gels may be visually analyzed using Flicker-comparison (Electrophoresis 1997, 18, 122-140) as one of the WebGel methods for qualitative analysis. Quantitative exploratory data

  14. Role of gel dosimeters in boron neutron capture therapy

    Gel dosimeters have acquired a unique status in radiotherapy, especially with the advent of the new techniques in which there is a need for three-dimensional dose measurement with high spatial resolution. One of the techniques in which the use of gel dosimeters has drawn the attention of the researchers is the boron neutron capture therapy. Exploring the history of gel dosimeters, this paper sets out to study their role in the boron neutron capture therapy dosimetric process. - Highlights: • Gel dosimeters have been investigated. • Conventional dosimetric proses of BNCT has been investigated. • Role of gel dosimeters in BNCT has been investigated

  15. Sol-gel Technology for Sensor Applications (Review Paper

    N. K. Chaudhury

    2007-05-01

    Full Text Available Sol-gel processes refer to the transition of predefined compositions of inorganic alkoxidesprecursors from liquid sol phase to solid gel phase. The phenomenon of sol-gel was known tomankind for more than 150 years. It is because of concerted efforts of researchers frommultidisciplinary fields, sol-gel science transformed to technology. Several products are alreadycommercially available for applications in optical coatings, nanocomposites, and public healthcare.Potential applications in the areas of biosensors and environmental monitoring are expected.Newer applications with nanotechnology appear too exciting. An attempt has been made toaddress important applications of sol-gel technology, particularly in sensing techniques fromthe defence perspective.

  16. Micro-size polyacrylamide gel electrophoresis system

    Hinson, W. G.; Pipkin, J. L.; Anson, J. F.; Casciano, D. A.; Burns, E. R.

    1987-09-01

    The development and characterization of a micro-size two-dimensional polyacrylamide gel electrophoresis system is described. Some of the techniques which have evolved with use of the system are also discussed. This apparatus has unique features which provide advantages over other small scale units. Up to ten first- and second-dimension gels can be processed simultaneously with excellent resolution of protein regions. Consistent reproducibility is possible from protein samples as small as 400 ng and individual protein regions as small as 1 pg can be visualized by silver staining of the two-dimensional gels. Similar sensitivities are achieved in autoradiographs of 3H-labeled proteins extracted from the nuclei of cultured cells. The application of this system in conjunction with flow cytometric examination of nuclear DNA and electrostatic cell sorting of specific cell nuclei to provide homogeneous sample populations, allows subtle variations in isotope incorporation in proteins to be detected; whereas many times in generalized tissue samples these changes are masked. Also, these techniques elucidate the effects of external stimuli (chemicals, drugs, or environment) on protein synthesis and phosphorylation for analyses and comparison. Fabrication drawings are available upon request.

  17. Gel Electrophoresis of Gold-DNA Nanoconjugates

    T. Pellegrino

    2007-01-01

    Full Text Available Gold-DNA conjugates were investigated in detail by a comprehensive gel electrophoresis study based on 1200 gels. A controlled number of single-stranded DNA of different length was attached specifically via thiol-Au bonds to phosphine-stabilized colloidal gold nanoparticles. Alternatively, the surface of the gold particles was saturated with single stranded DNA of different length either specifically via thiol-Au bonds or by nonspecific adsorption. From the experimentally determined electrophoretic mobilities, estimates for the effective diameters of the gold-DNA conjugates were derived by applying two different data treatment approaches. The first method is based on making a calibration curve for the relation between effective diameters and mobilities with gold nanoparticles of known diameter. The second method is based on Ferguson analysis which uses gold nanoparticles of known diameter as reference database. Our study shows that effective diameters derived from gel electrophoresis measurements are affected with a high error bar as the determined values strongly depend on the method of evaluation, though relative changes in size upon binding of molecules can be detected with high precision. Furthermore, in this study, the specific attachment of DNA via gold-thiol bonds to Au nanoparticles is compared to nonspecific adsorption of DNA. Also, the maximum number of DNA molecules that can be bound per particle was determined.

  18. Sol–gel processing of carbidic glasses

    L M Manocha; E Yasuda; Y Tanabe; S Manocha; D Vashistha

    2000-02-01

    Carbon incorporation into the silicate network results in the formation of rigid carbidic glasses with improved physical, mechanical and thermal properties. This generated great interest in the development of these heteroatom structured materials through different processing routes. In the present studies, sol–gel processing has been used to prepare silicon based glasses, especially oxycarbides through organic–inorganic hybrid gels by hydrolysis–condensation reactions in silicon alkoxides, 1,4-butanediol and furfuryl alcohol with an aim to introduce Si–C linkages in the precursors at sol level. The incorporation of these linkages has been studied using IR and NMR spectroscopy. These bonds, so introduced, are maintained throughout the processing, especially during pyrolysis to high temperatures. In FFA–TEOS system, copolymerization with optimized mol ratio of the two results in resinous mass. This precursor on pyrolysis to 1000°C results in Si–O–C type amorphous solid black mass. XRD studies on the materials heated to 1400°C exhibit presence of crystalline Si–C and cristobalites in amorphous Si–O–C mass. In organic–inorganic gel system, the pyrolysed mass exhibits phase stability up to much higher temperatures. The carbidic materials so produced have been found to exhibit good resistance against oxidation at 1000°C.

  19. A reproducible, high throughput method for fabricating fibrin gels

    Murphy Kaitlin C

    2012-08-01

    Full Text Available Abstract Background Fibrin gels are a promising biomaterial for tissue engineering. However, current fabrication methods are time intensive with inherent variation. There is a pressing need to develop new and consistent approaches for producing fibrin-based hydrogels for examination. Findings We developed a high throughput method for creating fibrin gels using molds fabricated from polydimethylsiloxane (PDMS. Fibrin gels were produced by adding solutions of fibrinogen and thrombin to cylindrical defects in a PDMS sheet. Undisturbed gels were collected by removing the sheet, and fibrin gels were characterized. The characteristics of resulting gels were compared to published data by measuring compressive stiffness and osteogenic response of entrapped human mesenchymal stem cells (MSCs. Gels exhibited compressive moduli nearly identical to our previously reported fabrication method. Trends in alkaline phosphatase activity, an early marker of osteogenic differentiation in MSCs, were also consistent with previous data. Conclusions These findings demonstrate a streamlined approach to fibrin gel production that drastically reduces the time required to make fibrin gels, while also reducing variability between gel batches. This fabrication technique provides a valuable tool for generating large numbers of gels in a cost-effective manner.

  20. Fabrication, modeling and optimization of an ionic polymer gel actuator

    The modeling of the electro-active behavior of ionic polymer gel is studied and the optimum conditions that maximize the deflection of the gel are investigated. The bending deformation of polymer gel under an electric field is formulated by using chemo-electro-mechanical parameters. In the modeling, swelling and shrinking phenomena due to the differences in ion concentration at the boundary between the gel and solution are considered prior to the application of an electric field, and then bending actuation is applied. As the driving force of swelling, shrinking and bending deformation, differential osmotic pressure at the boundary of the gel and solution is considered. From this behavior, the strain or deflection of the gel is calculated. To find the optimum design parameter settings (electric voltage, thickness of gel, concentration of polyion in the gel, ion concentration in the solution, and degree of cross-linking in the gel) for bending deformation, a nonlinear constrained optimization model is formulated. In the optimization model, a bending deflection equation of the gel is used as an objective function, and a range of decision variables and their relationships are used as constraint equations. Also, actuation experiments are conducted using poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) gel and the optimum conditions predicted by the proposed model have been verified by the experiments

  1. Colloid molecular weight estimation by gel chromatography/acrylamide gel electrophoresis

    Size or molecular weight (MW) estimation of radiolabeled collides in aqueous solutions has long been a problem. The authors have prepared several minimicroaggregated albumin colloids (mμAA) by heat denaturation of stannous-containing HSA solutions at pH 7.0, 7.5, and 8.5). The resulting colloids were labeled with Tc-99m and compared with Au-198 colloid and Tc-99m-antimony sulfide colloid (Tc-99m-Sb/sub 2/S3) by gel chromatography and gel electrophoresis. Tc-99mm-mμAA aggregated at pH 7.0 and the Au-198 colloid appeared in the external void volume of a BioRad A5.0 agarose column indicating an apparent MW of > 5 x 10/sup 6/ daltons. The pH7.5 Tc-99m-mμAA, migrated within the filtration range of the column as did a small fraction of Tc-99m-Sb/sub 2/S/sub 3/, suggesting that the MW is between 6 x 10/sup 4/ - 5 x 10/sup 6/ daltons. The Tc-99m-mμAA, aggregated at pH 8.5, had an apparent MW on gel filtration similar to that of untreated albumin, MW 6.6 x 10-/sup 4/ daltons. The mobilities of the colloids, on acrylamide disc gel electrophoresis, were consistent with the results on gel chromatography. The largest colloids, Au-198 colloid and pH 7.0 Tc-99m-mμAA, barely entered the separating gel; intermediate sized colloids, a small fraction of Tc-99m-Sb/sub 2/S/sub 3/ and pH 7.5 Tc-99m-mμAA migrated farther into the separating gel; while pH 8.5 Tc-99m-mμAA had mobility approaching that of untreated albumin. Lymphoscintigraphy studies using these colloids in animals showed the predicted, particle size-related differences in migration and clearance. The authors conclude that gel chromatography and gel electrophoresis are useful methods for estimating the apparent size of the colloidal particles

  2. Formation of magnetite nanoparticles in poly(acrylamide) gels

    Starodubtsev, Sergey G [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Saenko, Evheniy V [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Dokukin, Maxim E [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Aksenov, Viktor L [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Klechkovskaya, Vera V [Institute of Crystallography, Russian Academy of Sciences, 59 Leninsky Prospekt, Moscow 117333 (Russian Federation); Zanaveskina, Irina S [Institute of Crystallography, Russian Academy of Sciences, 59 Leninsky Prospekt, Moscow 117333 (Russian Federation); Khokhlov, Alexei R [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation)

    2005-03-16

    Magnetic gels with magnetite nanoparticles incorporated in a matrix of poly(acrylamide) gel were studied. Magnetite was synthesized through coprecipitation of Fe(II) and Fe(III) in the gel phase, in the solution of linear polymer and in aqueous solution without polymer in alkaline media. The effects of network structure and of the concentration of iron salts in the swollen networks on the composition, structure and properties of magnetic gels have been studied by electron diffraction, XRD, transmission electron microscopy and vibration sample magnetometry. The average size of magnetite nanoparticles, D, is of the order of 10 nm. It decreases with the increase of polymer concentration in the gel phase. In the dried gels the particles form spherical aggregates (diameter about 150 nm), whereas in the solution of linear polymer, in the aqueous solution of iron salts and in the gel with high content of polymer the aggregates have irregular shape.

  3. Antioxidant effect of green tea on polymer gel dosimeter

    Samuel, E. J. J.; Sathiyaraj, P.; Deena, T.; Kumar, D. S.

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer.

  4. Antioxidant effect of green tea on polymer gel dosimeter

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer

  5. Responsive Gel-Gel Phase Transitions in Artificially Engineered Protein Hydrogels

    Olsen, B. D.

    2012-02-01

    Artificially engineered protein hydrogels provide an attractive platform for biomedical materials due to their similarity to components of the native extracellular matrix. Engineering responsive transitions between shear-thinning and tough gel phases in these materials could potentially enable gels that are both shear-thinning and tough to be produced as novel injectable biomaterials. To engineer a gel with such transitions, a triblock copolymer with thermoresponsive polymer endblocks and an artificially engineered protein gel midblock is designed. Temperature is used to trigger a transition from a single network protein hydrogel phase to a double network phase with both protein and block copolymer networks present at different length scales. The thermodynamics of network formation and resulting structural changes are established using small-angle scattering, birefringence, and dynamic scanning calorimetry. The formation of the second network is shown to produce a large, nonlinear increase in the elastic modulus as well as enhancements in creep compliance and toughness. Although the gels show yielding behavior in both the single and double network regimes, a qualitative change in the deformation mechanism is observed due to the structural changes.

  6. Time-dependent gel to gel transformation of a peptide based supramolecular gelator.

    Baral, Abhishek; Basak, Shibaji; Basu, Kingshuk; Dehsorkhi, Ashkan; Hamley, Ian W; Banerjee, Arindam

    2015-06-28

    A dipeptide with a long fatty acid chain at its N-terminus gives hydrogels in phosphate buffer in the pH range 7.0-8.5. The hydrogel with a gelator concentration of 0.45% (w/v) at pH 7.46 (physiological pH) provides a very good platform to study dynamic changes within a supramolecular framework as it exhibits remarkable change in its appearance with time. Interestingly, the first formed transparent hydrogel gradually transforms into a turbid gel within 2 days. These two forms of the hydrogel have been thoroughly investigated by using small angle X-ray scattering (SAXS), powder X-ray diffraction (PXRD), field emission scanning electron microscopic (FE-SEM) and high-resolution transmission electron microscopic (HR-TEM) imaging, FT-IR and rheometric analyses. The SAXS and low angle PXRD studies substantiate different packing arrangements for the gelator molecules for these two different gel states (the freshly prepared and the aged hydrogel). Moreover, rheological studies of these two gels reveal that the aged gel is stiffer than the freshly prepared gel. PMID:26016677

  7. Investigation of the Peroxovanadate Sol-Gel Process and Characterization of the Gels

    Craig Joseph Fontenot

    2001-12-31

    In general, the peroxovanadate solution sol-gel process can be thought of as consisting of two parts: (1) the decomposition of the peroxo species and (2) cation hydrolysis leading to gelation. By controlling the synthesis conditions, both layered and amorphous compounds can be created. However, the type of water coordination observed in these gels was found to be identical no matter what the long-range order. The current work clarified many of the discrepancies found in the literature and offered much new valuable information. Highlights include the types of vanadium environments present at various stages of hydration, the role of adsorbed water, oxygen exchange from adsorbed water into the gel sites, and the ability to create metastable VMoO solid solution phases. These results could have a variety of impacts on future catalysis research.

  8. Deuterium isotope effect on swelling process in aqueous polymer gels

    The deuterium isotope effects on the swelling process of typical aqueous polymer gels (poly(N-isopropylacrylamide) gel and polyacrylamide gel) have been investigated in this study. The swelling times of both the poly(N-isopropylacrylamide) gel and the polyacrylamide gel in heavy water are longer than those in water. The deuterium isotope effect in the swelling process of gels is mainly arising from the higher viscosity in heavy water than in water. The additional deuterium isotope effect on the diffusion coefficient related to the swelling process should be due to the larger microscopic friction arising from the stronger polymer-solvent interaction in heavier water than in water. We also discuss in this paper the deuterium isotope effects on the size of the aqueous gels in the equilibrium state. Interestingly, the size in the equilibrium state of poly(N-isopropylacrylamide) gel in heavy water is larger than that in water. In contrast to poly(N-isopropylacrylamide) gel, the size in the equilibrium state of polyacrylamide gel in heavy water is smaller than that in water. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Fluorescent thin gel films using organic dyes and pigments

    Nakazumi, Hiroyuki; Takashi, Tarao; Taniguchi, Shin-ichi; Nanto, Hidehito

    1997-10-01

    New organic-inorganic fluorescent thin gel films included with laser dyes or fluorescent organic pigments have been prepared for display application. The florescent dyes (benzoxazolium, pyrromethene, and rhodamine dyes) and super-fine particles of fluorescent pigments (coumarin and perylene) were successfully incorporated into thin silicate gel films prepared from tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), and methoxysilane oligomer (MTSO) under acid catalyzed hydrolysis. The blue, green, and red luminescence were observed from these thin films (thickness: 100 - 400 nm), respectively. Fluorescence spectra, fluorescent quantum yield and lifetime of thin gel films are examined. Fluorescent peaks for most of dyes and pigments used in gel films were similar to those in solution, and fluorescent lifetime for dyes and pigments used in gel films were 2.9 - 4.5 ns. Photostability of fluorescent gel films is dependent on fluorescent organic dyes and pigments used and/or silicate gel matrixes. Coumarin and perylene pigments have higher fluorescent quantum yield in gel film prepared from MTSO. The large Stokes shift was observed in fluorescent gel film using coumarin and benzoxazolium dyes. The coumarin and perylene pigments are significantly photo- stable in gel film prepared from MTSO, and photodegradation of perylene red after irradiation of 500 W Xi-lamp for 30 min is below 20%.

  10. Platelet gel for healing cutaneous chronic wounds.

    Crovetti, Giovanni; Martinelli, Giovanna; Issi, Marwan; Barone, Marilde; Guizzardi, Marco; Campanati, Barbara; Moroni, Marco; Carabelli, Angelo

    2004-04-01

    Wound healing is a specific host immune response for restoration of tissue integrity. Experimental studies demonstrated an alteration of growth factors activity due to their reduced synthesis, increased degradation and inactivation. In wound healing platelets play an essential role since they are rich of alpha-granules growth factors (platelet derived growth factor--PDGF; transforming growth factor-beta--TGF-beta; vascular endothelial growth factor--VEGF). Topical use of platelet gel (PG), hemocomponent obtained from mix of activated platelets and cryoprecipitate, gives the exogenous and in situ adding of growth factors (GF). The hemocomponents are of autologous or homologous origin. We performed a technique based on: multicomponent apheretic procedure to obtain plasma rich platelet and cryoprecipitate; manual processing in an open system, in sterile environment, for gel activation. Every step of the gel synthesis was checked by a quality control programme. The therapeutic protocol consists of the once-weekly application of PG. Progressive reduction of the wound size, granulation tissue forming, wound bed detersion, regression and absence of infective processes were considered for evaluating clinical response to hemotherapy. 24 patients were enrolled. They had single or multiple cutaneous ulcers with different ethiopathogenesis. Only 3 patients could perform autologous withdrawal; in the others homologous hemocomponent were used, always considering suitability and traceability criteria for transfusional use of blood. Complete response was observed in 9 patients, 2 were subjected to cutaneous graft, 4 stopped treatment, 9 had partial response and are still receiving the treatment. In each case granulation tissue forming increased following to the first PG applications, while complete re-epithelization was obtained later. Pain was reduced in every treated patient. Topical haemotherapy with PG may be considered as an adjuvant treatment of a multidisciplinary process

  11. Higher Gel'fand-Dikii structures

    Enriquez, B; Rubtsov, V N

    1993-01-01

    We apply the procedure of Magri and Weinstein to produce an infinity of compatible Poisson structures on a bihamiltonian manifold, to the case of the KdV phase space. The higher Gel'fand-Dikii structures thus obtained contain non local terms, which we express with the help of the r.h.s. of the KdV hierarchy. We also give a generating function for all these Poisson structues, in terms of the Baker-Akhiezer functions. Finally we describe the symplectic leaves of these Poisson structures.

  12. Electrochemical Study of Conductive Gel Polymer

    Zhaohui Li; Jing Jiang; Gangtie Lei

    2005-01-01

    @@ 1Introduction Conventional ion-conducting polymer consists of electrolyte salt and polymer matrix, so-called salt-inpolymer. It possesses lower conductivity because the migration of ions depends on the motion of polymer segmental. To increase the ionic conductivity, a kind of gel polymer film (GPF) was prepared by in situ polymerization of methyl methacrylate (MMA) monomer in room-temperature ionic liquid(RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6). Due to immeasurably low vapor pressure, high ionic conductivity, and greater thermal and electrochemical stability, BMIPF6 is suitable electrolyte salts for ion-conducting polymer.

  13. Comparison effect of azithromycin gel 2% with clindamycin gel 1% in patients with acne

    Mokhtari, Fatemeh; Faghihi, Gita; Basiri, Akram; Farhadi, Sadaf; Nilforoushzadeh, Mohammadali; Behfar, Shadi

    2016-01-01

    Background: Acne vulgaris is the most common skin disease. Local and systemic antimicrobial drugs are used for its treatment. But increasing resistance of Propionibacterium acnes to antibiotics has been reported. Materials and Methods: In a double-blind clinical trial, 40 patients with mild to moderate acne vulgaris were recruited. one side of the face was treated with Clindamycin Gel 1% and the other side with Azithromycin Topical Gel 2% BID for 8 weeks and then they were assessed. Results: Average age was 21. 8 ± 7 years. 82.5% of them were female. Average number of papules, pustules and comedones was similarly reduced in both groups and, no significant difference was observed between the two groups (P > 0.05, repeated measurs ANOVA). The mean indexes of ASI and TLC also significantly decreased during treatment in both groups, no significant difference was observed between the two groups. (P > 0.05, repeated measurs ANOVA). Also, impact of both drugs on papules and pustules was 2-3 times greater than the effect on comedones. Average satisfaction score was not significant between the two groups (P = 0.6, repeated measurs ANOVA). finally, frequency distribution of complications was not significant between the two groups (P > 0.05, Fisher Exact test). Conclusion: Azithromycin gel has medical impact at least similar to Clindamycin Gel in treatment of mild to moderate acne vulgaris, and it may be consider as suitable drug for resistant acne to conventional topical therapy. PMID:27169103

  14. Role and properties of the gel formed during nuclear glass alteration: importance of gel formation conditions

    A French SON 68 nuclear glass sample was experimentally altered to assess the mechanisms limiting the glass alteration kinetics, especially during the transition phase between the initial rate r0 and the final rate under silicon saturation conditions. A glass specimen was altered at the initial rate for one week to form a silicon-depleted non-protective gel; the specimen was then leached under static conditions at a glass-surface-to-solution-volume (S/V) ratio of 500 m-1 and the alteration kinetics were compared with those of a pristine glass specimen altered under the same conditions. Unexpectedly, after static leaching the previously leached glass was 2.7 times as altered as the pristine specimen, and the steady-state silicon concentration was twice as high for the previously leached specimen. STEM characterization of the alteration films showed that the initial non-protective gel constituted a silicon pump with respect to the glass, and that the glass alteration kinetics were limited only when a fraction of the gel became saturated with silicon, and exhibited protective properties. This work also shows that silicon recondensation was uniform at micrometer scale: the silicon hydrolyzed at the reaction interface then diffused before recondensing over a length comparable to the gel thickness. In addition to these findings, this investigation suggests a reinterpretation of the effect of the S/V ratio on the glass alteration kinetics and on the steady-state dissolved silicon concentration

  15. A simple gel electrophoresis method for separating polyhedral gold nanoparticles

    Kim, Suhee; Lee, Hye Jin

    2015-07-01

    In this paper, a simple approach to separate differently shaped and sized polyhedral gold nanoparticles (NPs) within colloidal solutions via gel electrophoresis is described. Gel running parameters for separating efficiently gold NPs including gel composition, added surfactant types and applied voltage were investigated. The plasmonic properties and physical structure of the separated NPs extracted from the gel matrix were then investigated using transmission electron microscopy (TEM) and UV-vis spectrophotometry respectively. Data analysis revealed that gel electrophoresis conditions of a 1.5 % agarose gel with 0.1 % sodium dodecyl sulfate (SDS) surfactant under an applied voltage of 100 V resulted in the selective isolation of ~ 50 nm polyhedral shaped gold nanoparticles. Further efforts are underway to apply the method to purify biomolecule-conjugated polyhedral Au NPs that can be readily used for NP-enhanced biosensing platforms.

  16. Explorative data analysis of two-dimensional electrophoresis gels

    Schultz, J.; Gottlieb, D.M.; Petersen, Marianne Kjerstine;

    2004-01-01

    Methods for classification of two-dimensional (2-DE) electrophoresis gels based on multivariate data analysis are demonstrated. Two-dimensional gels of ten wheat varieties are analyzed and it is demonstrated how to classify the wheat varieties in two qualities and a method for initial screening of...... gels is presented. First, an approach is demonstrated in which no prior knowledge of the separated proteins is used. Alignment of the gels followed by a simple transformation of data makes it possible to analyze the gels in an automated explorative manner by principal component analysis, to determine...... if the gels should be further analyzed. A more detailed approach is done by analyzing spot volume lists by principal components analysis and partial least square regression. The use of spot volume data offers a mean to investigate the spot pattern and link the classified protein patterns to distinct...

  17. G-Quadruplex Guanosine Gels and Single Walled Carbon Nanotubes

    Yuehua Yu

    2013-12-01

    Full Text Available Solubilization of single walled carbon nanotubes (SWNTs in aqueous gel phases formed by reversible, G-quadruplex self-assembly of guanosine monophosphate (GMP alone or with guanosine (Guo is described. Unlike other media and methods for aqueous solubilization of SWNTs, the guanosine gels (“G-gels” are found to readily disperse high (>mg/mL concentrations of individual rather than bundled SWNTs. SWNT dispersions in GMP alone precipitate in several hours and re-form upon shaking; however, dispersions in the binary GMP/Guo gels are indefinitely stable. Increasing GMP or KCl concentration in the binary gels increased the relative abundance of large diameter and semi-conducting SWNTs. Different gel compositions also displayed different selectivities toward SWNTs of different chiralities. These results indicate a strong connection between the self-assembled G-gels and the dimensions and structures of the SWNTs that they solubilize.

  18. A NOVEL OPHTHALMIC DRUG DELIVERY SYSTEM: IN-SITU GEL

    A.P. Patil*, A.A. Tagalpallewar, G.M. Rasve, A.V. Bendre, P.G. Khapekar

    2012-09-01

    Full Text Available The ophthalmic in-situ gels now days proved an palpable sustained drug delivery in various eye diseases. The formulation of in-situ gels for eye which carries the advantages like easy for administration, reduces frequency of dose and improves patient compliance. The formation of in-situ gels depends on phase transition system or sol-gel transition system. The formulation approaches like temperature intonation, pH change and presence of ions from which the drug gets released in a sustained and controlled manner are utilised for in-situ gels. Various polymers that are used for the formulation of in-situ gels include chitosan, Pluronic F-127, poly-caprolactone, gellan gum, alginic acid, xyloglucan, pectin etc.

  19. Porphyrin gels reinforced by sol-gel reaction via the organogel phase.

    Kishida, Takanori; Fujita, Norifumi; Sada, Kazuki; Shinkai, Seiji

    2005-10-11

    Porphyrins bearing four urea-linked dodecyl groups (3a) or four urea-linked triethoxysilylpropyl groups (3TEOS) at their peripheral positions were synthesized. 3a tends to assemble into a sheetlike two-dimensional structure due to the predominant hydrogen-bonding interaction among the urea groups and acts as a moderate gelator of organic solvents. On the other hand, its Cu(II) compelx (3a.Cu) tends to assemble into a fibrous one-dimensional structure due to the predominant porphyrin-porphyrin pi-pi stacking interaction and acts as an excellent gelator of many organic solvents. 3TEOS and 3TEOS.Cu, which also act as gelators, afforded similar superstructures as those of 3a and 3a.Cu, respectively, and as evidenced by SEM and TEM observations and XRD measurements, the original superstructures could be precisely immobilized by in situ sol-gel polycondensation of the triethoxysilyl groups. The TEM images of 3a gels and 3TEOS gels after sol-gel polycondensation showed a fine striped structure, the periodical distance of which was either 2 or 4 nm. X-ray crystallographic analysis of a single crystal obtained from a reference porphyrin bearing four urea-linked butyl groups revealed that there are two different porphyrin-stacked columns in the crystal and both the 2 nm distance and the 4 nm distance can appear, depending on the observation tilting angle. The hybrid gel prepared from 3TEOS.Cu by sol-gel polycondensation showed unique physicochemical properties such as a high sol-gel phase-transition temperature (>160 degrees C), sufficient elasticity, high mechanical strength, etc. Thus, the present study has established new concepts for molecular design of porphyrin-based gelators on the basis of cooperative and/or competitive actions of hydrogen-bonding and pi-pi stacking interactions and for immobilization of their superstructures leading to development of new functional organic/inorganic hybrid materials. PMID:16207018

  20. Block copolymer ion gels for gas separation

    Gu, Yuanyan; Lodge, Timothy

    2012-02-01

    Carbon dioxide removal from light gases (eg. N2, CH4, and H2) is a very important technology for industrial applications such as natural gas sweetening, CO2 capture from coal-fire power plant exhausts and hydrogen production. Current CO2 separation method uses amine-absorption, which is energy-intensive and requires frequent maintenance. Membrane separation is a cost-effective solution to this problem, especially in small-scale applications. Ionic liquids have recently received increasing interest in this area because of their selective solubility for CO2 and non-volatility. However, ionic liquid itself lacks the persistent structure and mechanical integrity to withstand the high pressure for gas separation. Here, we report the development and gas separation performances of physically crosslinked ion gels based on self-assembly of ABA-triblock copolymers in ionic liquids. Three different types of polymers was used to achieve gelation in ionic liquids. Specifically, a triblock copolymer ion gel with a polymerized ionic liquid mid-block shows performances higher than the upper bound of well-known ``Robeson Plot'' for CO2/N2.

  1. Purification of radiolabeled RNA products using denaturing gel electrophoresis

    Adachi, Hironori; Yu, Yi-Tao

    2014-01-01

    This unit discusses a basic method for purification of radiolabeled RNAs using denaturing polyacrylamide gel electrophoresis. The method consists of a number of experimental procedures, including total RNA preparation from yeast cells, isolation of a specific RNA from total yeast RNA, RNA 3' terminal labeling using nucleotide (5’[32P]pCp) addition (via ligation), denaturing (8 M urea) polyacrylamide gel electrophoresis, and RNA extraction from the gel slice. Key points for achieving good elec...

  2. Guidelines for reporting the use of gel electrophoresis in proteomics.

    Gibson, Frank; Anderson, Leigh; Babnigg, Gyorgy; Baker, Mark; Berth, Matthias; Binz, Pierre-Alain; Borthwick, Andy; Cash, Phil; Day, Billy W.; Friedman, David B; Garland, Donita; Gutstein, Howard B.; Hoogland, Christine; Jones, Neil A.; Khan, Alamgir

    2008-01-01

    the MIAPE Gel Electrophoresis (MIAPE-GE) guidelines specify the minimum information that should be provided when reporting the use of n-dimensional gel electrophoresis in a proteomics experiment. Developed through a joint effort between the gel-based analysis working group of the Human Proteome Organisation's Proteomics Standards Initiative (HUPO-PSI; http://www.psidev.info/) and the wider proteomics community, they constitute one part of the overall Minimum Information about a Proteomics Exp...

  3. Cervical Ripening With Prostaglandin Gel and Hygroscopic Dilators

    J. U. Hibbard; A. Shashoua; Adamczyk, C.; Ismail, M

    1998-01-01

    Objective: To study the effectiveness and morbidity of adding hygroscopic cervical dilators to prostaglandin gel for cervical ripening and labor induction.Study design: Patients of at least 34 weeks’ gestation with a medical indication for induction of labor and with a modified Bishop score of 5 or less were randomized to receive either prostaglandin gel or prostaglandin gel with hygroscopic cervical dilators. Primary outcomes were time to delivery, change in cervical score, and infection. Se...

  4. Cervical ripening with prostaglandin gel and hygroscopic dilators.

    J. U. Hibbard; A. Shashoua; Adamczyk, C.; Ismail, M

    1998-01-01

    OBJECTIVE: To study the effectiveness and morbidity of adding hygroscopic cervical dilators to prostaglandin gel for cervical ripening and labor induction. STUDY DESIGN: Patients of at least 34 weeks' gestation with a medical indication for induction of labor and with a modified Bishop score of 5 or less were randomized to receive either prostaglandin gel or prostaglandin gel with hygroscopic cervical dilators. Primary outcomes were time to delivery, change in cervical score, and infection. S...

  5. Stability of the gel formed during nuclear glass alteration

    This thesis is divided in two parts. The first part is dedicated to the study of the protective properties of the gels formed during the alteration of nuclear glass and the second part the stability of these gels after drying and the effect of the sulfate ions are studied. The protective properties of the gel of SON68 glass are assessed at different alteration progress and related to their morphology analyzed by X-ray reflectometry and gas adsorption. Initially a depleted glass layer is obtained, followed by the formation of a gel with an open porosity. Subsequently the gel densifies as the glass alteration rate decreases and finally the pore size increases upon the formation of a dense and thin zone within the film on the glass surface. The increase of the gradient density zone could explain the increase of the protective properties of the gel. A high reaction progress, when the thin and dense zone within the gel is formed, the protective properties are constant. Various simplified glasses are also studied. At high reaction progress there is a dense zone within the gel. The location of this zone depends on the glass composition which control the competition between the species diffusion in solution and their recondensation. The gel morphology, the protective properties, its stability and the glass composition are correlated. The drying induces some modifications of the morphology of the SON68 glass alteration layer (density, thickness and porosity) and of the mechanical properties (cracks, adhesion on glass). For protective gels these modifications are limited and don't raise the protective properties of the gel. The effect of the sulfate ions in a closed system is essentially to complex calcium. For sulfate ions concentrations in geological repository, the stability of the gel is not raised. (author)

  6. Theory of volume transition in polyelectrolyte gels with charge regularization

    Hua, Jing; Mitra, Mithun K; Muthukumar, M.

    2012-01-01

    We present a theory for polyelectrolyte gels that allow the effective charge of the polymer backbone to self-regulate. Using a variational approach, we obtain an expression for the free energy of gels that accounts for the gel elasticity, free energy of mixing, counterion adsorption, local dielectric constant, electrostatic interaction among polymer segments, electrolyte ion correlations, and self-consistent charge regularization on the polymer strands. This free energy is then minimized to p...

  7. Agarose Gel Electrophoresis for the Separation of DNA Fragments

    Lee, Pei Yun; Costumbrado, John; Hsu, Chih-Yuan; Kim, Yong Hoon

    2012-01-01

    Agarose gel electrophoresis is the most effective way of separating DNA fragments of varying sizes ranging from 100 bp to 25 kb1. Agarose is isolated from the seaweed genera Gelidium and Gracilaria, and consists of repeated agarobiose (L- and D-galactose) subunits2. During gelation, agarose polymers associate non-covalently and form a network of bundles whose pore sizes determine a gel's molecular sieving properties. The use of agarose gel electrophoresis revolutionized the separation of DNA....

  8. The Substitute Brain and the Potential of the Gel Model

    Pomfret, Roland; Miranpuri, Gurwattan; Sillay, Karl

    2013-01-01

    This purpose of this paper is to review the recent history of the use of agarose gels. Although originally confined to electrophoresis work, agarose gels have proven themselves useful to a number of disciplines in the modern world, which includes brain infusion studies for research involving the treatment of various neurological conditions, such as Parkinson’s Disease. In reviewing the relevant research leading up to the modern day, this paper attempts to track agarose gels through their stag...

  9. Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

    Chen, Meiwan; Yang, Zhiwen; Wu, Hongmei; Pan, Xin; XIE, XIAOBAO; Wu, Chuanbin

    2011-01-01

    Purpose The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel) on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Patients and methods This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria...

  10. Electrophoretic properties of the scrapie agent in agarose gels.

    Prusiner, S B; Groth, D F; Bildstein, C; Masiarz, F R; McKinley, M P; Cochran, S P

    1980-01-01

    The molecular properties of the scrapie agent were investigated by subjecting partially purified preparations to electrophoresis on agarose gels. When electrophoresis was performed at room temperature in the presence of sodium dodecyl sulfate (NaDodSO4), most of the recoverable agent was found at the top of the gel, consistent with previous studies indicating aggregation of the agent upon exposure to elevated temperatures. In addition, less than 5% of the agent applied to the gel was found af...

  11. A systematic study of field inversion gel electrophoresis.

    Heller, C.; Pohl, F M

    1989-01-01

    The mobilities of oligomers of phage lambda DNA and of yeast chromosomes in agarose gels during field inversion gel electrophoresis (FIGE) were measured at different pulse times and electric fields. Also the ratios between forward and backward pulse times and/or field gradients were varied. The problem of 'band inversion' during FIGE, leading to an ambiguity in the mobility of large DNA fragments, was solved by using two dimensional gel electrophoresis with different parameters in the first a...

  12. Controlled Release Gel Formulations for Mucosal Drug Delivery

    Paulsson, Mattias

    2001-01-01

    Drug delivery to nasal or ocular mucosa for either local or systemic action faces many obstacles – these routes are protected by effective mechanisms. Gel formulations with suitable rheological and mucoadhesive properties increase the contact time at the site of absorption. However, drug release from the gel must be sustained if benefits are to be gained from the prolonged contact time. The work presented here is the characterization of gels and the determination of the mucoadhesive propertie...

  13. Burns and injuries resulting from the use of gel candles.

    Pickus, E J; Lionelli, G T; Parmele, J B; Lawrence, W T; Korentager, R A

    2001-01-01

    Scented gel candles are common decorative household items composed of gelled mineral oil, fragrances, and dye. Like traditional wax candles, they have an open flame. Because of defective design, there have been several burns and injuries caused by these products. Here we report our experience with a scald burn from a gel candle and describe 34 additional injuries attributed to gel candles previously unreported in the medical literature. PMID:11403248

  14. Engineering new supramolecular gels: From catalysis to drug delivery

    Bachl, Jürgen

    2015-01-01

    The present dissertation evaluates the design, characterization and potential applications of functional supramolecular gel-materials. Gels have attracted tremendous scientific interest as they can be obtained from natural sources or derive from readily available building blocks by facile preparation methods. They have conquered our daily life appearing as constituents of commercial products in the fields of biomedicine, agriculture, cosmetics, food thickeners and many more. Gel-materials exh...

  15. Volume Phase Transition of Polyelectrolyte Gels: Effects of Ionic Size

    Qu, Li-Jian; Zhang, Xinghua; Tang, Jiuzhou; Yan, Dadong

    2013-01-01

    Although the volume transition of the polyelectrolyte gel has been studied for decades, little research on the effects of size of the mobile ions has been conducted. In the present paper, Tanaka classical theory of polyelectrolyte gel is extended to the cases of mobile ions of finite volume. In the salt free limit, the theoretical results show that the discontinuous volume transition of the polyelectrolyte gel will become a continuous one with an increase of the counter-ionic size. An increas...

  16. Preparation of a novel composition-gradient thermosensitive gel

    Tokuyama, Hideaki; Sasaki, Masahiro; Sakohara, Shuji

    2006-01-01

    The feasibility of a novel composition-gradient copolymer gel, in which the composition gradually changes with the distance, was examined. The slab-shaped copolymer gels of a thermosensitive primary component, N-isopropylacrylamide (NIPA) and an ionic secondary component, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) or acrylic acid (AA), were prepared between two substrates of hydrophilic glass and hydrophobic polytetrafluoroethylene (Teflon). In the NIPA-co-AMPS gels, prepared at 40°C...

  17. Manual for starch gel electrophoresis: A method for the detection of genetic variation

    Aebersold, Paul B.; Winans, Gary A.; David J Teel; Milner, George B.; Utter, Fred M

    1987-01-01

    The procedure to conduct horizontal starch gel electrophoresis on enzymes is described in detail. Areas covered are (I) collection and storage of specimens, (2) preparation of tissues, (3) preparation of a starch gel, (4) application of enzyme extracts to a gel, (5) setting up a gel for electrophoresis, (6) slicing a gel, and (7) staining a gel. Recipes are also included for 47 enzyme stains and 3 selected gel buffers. (PDF file contains 26 pages.)

  18. Biochemical Identification of the Two Races of Radopholus similis by Polyacrylamide Gel Electrophoresis

    Huettel, R. N.; Dickson, D. W.; Kaplan, D. T.

    1983-01-01

    Analysis of proteins of the banana and citrus race of Radopholus similis was carried out by several different types of polyacrylamide gel electrophoresis. These included standard slab gel, SDS slab gel, gradient slab gel, and two-ditnensional slab gel electrophoresis. A major band difference was detected between the two races by slab gel electrophoresis. However, several other poorly resolved but consistent hands of high molecular weight proteins near the gel origin also were considered as di...

  19. Silica scintillating materials prepared by sol-gel methods

    Silica was investigated as a rad-hard alternative to organic polymer hosts for organic scintillators. Silica sol-gels were prepared by hydrolysis of tetramethoxysilane in alcohol solutions. organic dyes were incorporated into the gels by dissolving in methanol at the sol stage of gel formation. The silica sol-gel matrix is very rad-hard. The radiation stability of silica scintillators prepared by this method is dye-limited. Transient radioluminescence was measured following excitation with 30 ps pulses of 20 MeV electrons

  20. Nonlinear dynamics of self-oscillating polymer gels

    2010-01-01

    Self-oscillating polymer gels driven by Belousov-Zhabotinsky (BZ) chemical reaction are a new class of functional gels that have a wide range of potential applications (e.g., autonomously functioning membranes, actuate artificial muscles). However, the precise control of these gels has been an issue due to limited investigations of the influences of key system parameters on the characteristics of BZ gels. To address this deficiency, we studied the self-oscillating behavior of BZ gels using the nonline-ar dynamics theory and an Oregonator-like model, with focus placed upon the influences of various system parameters. The analysis of the oscillation phase indicated that the dynamic response of BZ gels represents the classical limit cycle oscillation. We then investigated the characteristics of the limit cycle oscillation and quantified the influences of key parameters (i.e., ini-tial reactant concentration, oxidation and reduction rate of catalyst, and response coefficient) on the self-oscillating behavior of BZ gels. The results demonstrated that sustained limit cycle oscillation of BZ gels can be achieved only when these key pa-rameters meet certain requirements, and that the pattern, period and amplitude of the oscillation are significantly influenced by these parameters. The results obtained in this study could enable the controlled self-oscillation of BZ gels system. This has several potential applications such as controlled drug delivery, miniature peristaltic pumps and microactuators.

  1. Polyacrylamide gel miniaturization improves protein visualization and autoradiographic detection

    Polyacrylamide gels shrink to one-quarter of their original area when soaked in a 50% (w/v) solution of polyethylene glycol. Gel miniaturization improves the contrast of protein bands, with four valuable consequences. (i) A 5- to 10-fold increase in sensitivity for Coomassie blue is observed. (ii) Gels are more durable; i.e., they resist tearing when wet and they do not crack during drying under vacuum. (iii) Shrunken gels give sharper photographic images and provide better interlane protein band comparisons. (iv) Condensed protein bands lead to an increased sensitivity for detecting low-abundance, radioactively-labeled proteins by fluorography

  2. Effect of bloom strength on radiochromic gel dosimeters

    The Fricke gel dosimeter has been the widely used dosimeter among the gel dosimeters because of its dose response characteristics and easy preparation. The ferrous to ferric conversion that happens in this gel dosimeter on irradiation, corresponds to the absorbed dose of radiation. Gel dosimetry in India is not moving forward because of the import restrictions on the commercially available high bloom strength gelatin (imported 300 bloom). The feasibility of using Fricke gel dosimeter prepared with the locally available gelatin of 240 bloom and 200 bloom were compared with the 300 bloom gelatin taken as standard. The gel samples were prepared with 5% gelatin by weight and irradiated with 60Co gamma radiation for a dose range from 0-3 Gy used clinically. The optical absorption of gel samples were analyzed using spectrophotometer at 585 nm and dose response curves were generated. The results indicate that Fricke gels prepared with 240 bloom have linear dose response and comparable with those prepared with 300 bloom but the use of gels prepared with 200 bloom was found to be limited because of its poor optical transmittance

  3. Study of polymer gel for dose imaging in radiotherapy

    Vanossi, E. [Dipartimento di Ingegneria Nucleare del Politecnico, Ce.S.N.E.F., Milano (Italy); INFN, Istituto Nazionale di Fisica Nucleare, Milano (Italy); Carrara, M. [S.C. Fisica Sanitaria, Fondazione IRCCS ' Istituto Nazionale Tumori' , Milano (Italy); Gambarini, G. [INFN, Istituto Nazionale di Fisica Nucleare, Milano (Italy); Dipartimento di Fisica dell' Universita, Milano (Italy)], E-mail: Grazia.Gambarini@mi.infn.it; Mariani, M. [Dipartimento di Ingegneria Nucleare del Politecnico, Ce.S.N.E.F., Milano (Italy); Valente, M. [INFN, Istituto Nazionale di Fisica Nucleare, Milano (Italy); Dipartimento di Fisica dell' Universita, Milano (Italy)

    2008-02-15

    Gel dosimeters in the form of layers are a promising tool for in-phantom absorbed dose imaging in radiotherapy, either with high gradient X-ray or electron radiation fields, as in conformal radiotherapies, or with neutron beams, as in boron neutron capture therapy (BNCT). A normoxic polymer gel has been studied, and the results are compared with those obtained with Fricke gel dosimeters exposed to the same fields and in the same phantom configuration. Although promising, polymer gel layers need further improvements in order to obtain higher reliability.

  4. Optimized Benzalkonium Chloride Gel: A Potential Vaginal Microbicides

    Xun-cheng DING; Wei-hua LI; Jie-fei LI; Qiang-yi WANG

    2007-01-01

    Objective To develop an optimized BZK gel with good pharmaceutical effect and less toxicity to vaginal mucosa.Methods Four methods as below were used to research the spermicidal activity of BZK gel: 1)in vitro spermicidal test; 2) in vivo spermicidal test in rabbits; 3) anti-fertility test in rabbits; 4)contraceptive test in rabbits. Mucosal irritation test was used in rats to evaluate the safety of optimized BZK gel. Microbiological assessments were used to research anti-STI pathogens (including treponema pallidum, neisseria gonorrhoeae, trichomona vaginalis, candida albicans,ureaplama urealyticum, herpes simplex virus type-2, chlamydiae trachomatis) effect of optimized BZK gel.Results In vitro spermicidal test, EC50 of BZK gel was 0.029 mg/ml, a little higher than that of N-9 (0.019 mg/ml). The MIC of BZK gel was 0.25 mg/ml, similar to that of N-9 (0.20 mg/ml).The vaginal mucosal irritation test in rats showed that 0.429% BZK gel showed only minimal vaginal irritation, and did not damage the vaginal epithelium or cause local inflammation in rats. Microbiological assessments showed that optimized BZK gel could inhibit or inactivate common STI pathogens even after 3-fold or 5-fold dilution.Conclusion Optimized BZK gel was an effective microbicides.

  5. Aging and nonlinear rheology of thermoreversible colloidal gels

    Wagner, Norman; Gordon, Melissa; Kloxin, Christopher

    Colloidal dispersions are found in a wide variety of consumer products such as paint, food and pharmaceuticals. We investigate gel formation and aging in a thermoreverible gel consisting of octadecyl-coated silica nanoparticles suspended in n-tetradecane. In this system, the octadecyl brush can undergo a phase change allowing the attractions between particles to be tuned by temperature (1,2). By probing the system with steady shear and large amplitude oscillatory shear, we have studied the effect of thermal history and shear history on gel formation and gel mechanical properties during aging. Gels were formed by approaching a common temperature from above and below to determine a reference state from which creep tests were conducted. Creep ringing was observed as expected for the viscoelastic gel. The rheological aging is interpreted in terms of the gel microstructure formed with differing thermal and shear histories to determine how processing affects structure. Recently proposed scaling laws for the rheology and structure under flow are explored within the context of gel aging (3). Through rheological and microstructural measurements, we will further the understanding of gel formation and aging in this model system which may be applied to processing conditions in an industrial setting.

  6. Application of CMPO containing gels to metal extraction

    Immersed in solubility-consistent organic solvents, high polymers can swell and form gels. Choosing the organic solvent among metal extracting solvents, metal extracting gels can be prepared. The advantages of the liquid-gel extraction process, in comparison with the liquid-liquid one, are to allow the extraction of metal cations from diluted aqueous solutions by using high aqueous-organic volume ratios (metal concentration in a few stages) with easy phase separations. Various CMPO (Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide) containing gels have been prepared, and the extraction of europium (and related actinides) has been studied. (author)

  7. Sol-gel Characteristics for Corrosion Resistance of Anodised Aluminium

    Whelan, Michael; Cassidy, John; Duffy, Brendan

    2013-01-01

    Conventional anodising electrolytes based on sulphuric acid, oxalic acid and phosphoric acid have been used to form nanoporous layers on AA3003-H14 and sealed with silane based sol-gel sealers. It is shown that the sol-gel chemistries have varying levels of pore penetration depending on the synthesis conditions. The extent of sol-gel penetration and pore sealing is analysed by electron microscopy and energy dispersive x-ray spectroscopy. To describe the sealing phenomena observed a sol-gel pe...

  8. High Impulse Nanoparticulate-Based Gel Propellants Project

    National Aeronautics and Space Administration — This proposed Small Business Innovative Research (SBIR) Phase I addresses the development of advanced gel propellants and determination of their suitability for...

  9. Multiwalled carbon nanotube reinforced biomimetic bundled gel fibres.

    Kim, Young-Jin; Yamamoto, Seiichiro; Takahashi, Haruko; Sasaki, Naruo; Matsunaga, Yukiko T

    2016-08-19

    This work describes the fabrication and characterization of hydroxypropyl cellulose (HPC)-based biomimetic bundled gel fibres. The bundled gel fibres were reinforced with multiwalled carbon nanotubes (MWCNTs). A phase-separated aqueous solution with MWCNT and HPC was transformed into a bundled fibrous structure after being injected into a co-flow microfluidic device and applying the sheath flow. The resulting MWCNT-bundled gel fibres consist of multiple parallel microfibres. The mechanical and electrical properties of MWCNT-bundled gel fibres were improved and their potential for tissue engineering applications as a cell scaffold was demonstrated. PMID:27200527

  10. Inclusion type radiochromic gel dosimeter for threedimensional dose verification

    For the verification of 3D dose distributions in modern radiation therapy, a new inclusion type radiochromic gel detector has been developed. In this gel, a hydrophobic leuco dye (leucomalachite green: LMG) was dissolved in water as an inclusion complex with highly branched cyclic dextrin. The radiation induced radical oxidation property of the LMG gel with various sensitizers was investigated. As a result, the optical dose responses were enhanced by the addition of bromoacetic acid and manganese (II) chloride. Unfavorable auto-oxidation of the gel was reduced when it was stored at 4°C

  11. PCR amplification on microarrays of gel immobilized oligonucleotides

    Strizhkov, Boris; Tillib, Sergei; Mikhailovich, Vladimir; Mirzabekov, Andrei

    2003-11-04

    The invention relates two general methods for performing PCR amplification, combined with the detection and analysis of the PCR products on a microchip. In the first method, the amplification occurs both outside and within a plurality of gel pads on a microchip, with at least one oligonucleotide primer immobilized in a gel pad. In the second method, PCR amplification also takes place within gel pads on a microchip, but the pads are surrounded by a hydrophobic liquid such as that which separates the individual gel pads into environments which resemble micro-miniaturized test tubes.

  12. Gel-eletroforese no diagnóstico da varíola Gel-electrophoresis in the smallpox diagnosis

    Julio A. Mesquita

    1972-01-01

    Full Text Available O emprego de gel-eletroforese no diagnóstico da varíola, demonstrou ser ao menos trinta vezes (30X mais sensível que o teste de agar-gel, nas condições descritas (tabela I. Doze (12 espécimes, cujos testes convencionais de inoculação em ovos embrionados e de agar-gel resultaram positivos, foram testados em suas diluições originais congeladas por mais de um ano, sendo seis deles revelados por gel-eletroforese enquanto nenhum o foi por agar-gel (tabela II. Trinta e três (33 amostras isoladas no laboratório, foram testadas com material colhido de membrana cório-alantóica da primeira inoculação para o diagnóstico, conservado em glicerina 50%, resultando 15 positivas em gel-eletroforese e apenas 3 em agar-gel (tabela II. Os últimos 60 espécimes recebidos para diagnóstico, através a Campanha de Erradicação da Varíola, também resultaram negativos em gel-eletroforese, que não mostrou falsos-positivos nas condições descritas.The test of gel-electrophoresis applied to the pox virus group showed to be at least thirth times (30X more sensitive than agar-gel test on the described conditions (Table I. Twelve specimens, which were positives form Smallpox in the conventional tests of egg inoculation and agar-gel difusion test, have been screened in their original dilutions frozen for more than 1 year and six of them were still detectable by gel-eletrophoresis, while by agar-gel test any of them was positive (Table II. Thirty three Smallpox isolates have been tested with material from first egg inoculation (chorioallantoic membranes which have been stored in glycerin 50%, at - 15ºC. Fifteen of them were still positive by gel-electrophoresis and only 3 by agar-gel (Table II. The last 60 specimens received for diagnosis from Smallpox Erradication Campaign (CEV, were negatives by both tests. The gel-electrophoresis, did not show false-positives on described conditions.

  13. Influence of Uranium and Polivinyl Alcohol Concentration in the Feed of Sol Gel Process on the Gel Spherical Product

    The gel particles have been made at various uranium and polyvinyl alcohol concentration in the sol gel process. The variables of uranium concentration were 0.3; 0.5; 0.7; 0.9; 1.1; 1.3; 1.5; 1.7; 1.9 and 2.1 M The variables of polyvinyl alcohol concentration were 0.3; 0.6; 0.9; 1.2; 1.5; 1.8; 2.1 and 2.4 M After drying the sol gel process products were heated at 300, 500 and 750°C during 4 hours. The gel particles were characterized using an optic microscope to know the shape and condition morphology of gel. From experimental result using uranium concentration of 0.3 until 2.1 M and polyvinyl alcohol of 1.8 until 2.4 M spherical and gel was formed elastic, after heating at 750°C it was unbreakable. At the concentration of polyvinyl alcohol from 0.3 to 0.5 M, the gel product was soft and broken after being dried. At the concentration of polyvinyl alcohol from 0.6 to 0.8 M, the dried gel product was not perfect. At the concentration of polyvinyl alcohol from 0.9 to 1.7 M, the gel product of gelation process was spherical and it was broken after being heated up to 300°C. (author)

  14. Coupling of gelation and glass transition in a biphasic colloidal mixture--from gel-to-defective gel-toglass

    Cheng, He; Jia, Di; Han, Charles

    The state transition from gel to glass is studied in a biphasic mixture of polystyrene core/poly (N-isopropylacrylamide) shell (CS) microgels and sulfonated polystyrene (PSS) particles. At 35 °C, the interaction between CS is due to short-range Van der Waals attraction while that between PSS is from long-range electrostatic repulsion. During variation of the relative ratio of the two species at a fixed apparent total volume fraction, the mixture exhibits a gel-to-defective gel-to-glass transition. When small amounts of PSS are introduced into the CS gel network, some of them are kinetically trapped, causing a change in its fractal structure, and act as defects to weaken the macroscopic gel strength. An increase of PSS content in the mixture promotes the switch from gel to defective gel, e . g . , the typical two-step yielding gel merges into one-step yielding. This phenomenon is an indication that inter-cluster bond breakage coincides with intra-cluster bond fracture. As the relative volume fraction of PSS exceeds a critical threshold, the gel network can no longer be formed; hence, the mixture exhibits characteristics of glass. A state diagram of the biphasic mixture is constructed, and the landscape of the different transitions will be described in future studies The financial support from the National Basic Research Program of China (973 Program, 2012CB821500) is gratefully acknowledged.

  15. Influence of application of chlorhexidine gel and curcumin gel as an adjunct to scaling and root planing: A interventional study

    Hugar, Shweta S.; Patil, Suvarna; Metgud, Renuka; Nanjwade, Basavraj; Hugar, Shivayogi M.

    2016-01-01

    Background: Currently, the most common therapy for periodontal diseases consists of professional scaling and root planing (SRP). However, it was found to be of limited efficacy especially in areas which are inaccessible to periodontal instrumentation. Therefore, treatment strategies using antimicrobials in conjunction with conventional therapy have evolved. Thus, the study was undertaken with an. Aim: To evaluate the efficacy of application of chlorhexidine gel and curcumin gel as an adjunct to SRP. Materials and Methods: The study was conducted on thirty chronic periodontitis patients who were divided into two groups as control and experimental groups using a split-mouth design. After SRP chlorhexidine gel was applied in control and curcumin gel in experimental groups. The plaque index, gingival index, sulcus bleeding index, probing pocket depth were recorded at baseline and subsequently after 1 month and 45 days. Results: The results revealed that both chlorhexidine gel and curcumin gel have an effect on mild to moderate periodontal pockets in chronic periodontitis patients, but greater reduction was observed in the experimental group than the control group. Conclusion: It can be concluded that both control and experimental gel can be used as an adjunct to SRP, but the curcumin gel was more effective than the chlorhexidine gel in the treatment of mild to moderate periodontal pockets with a significant reduction in the indice scores when compared to the baseline values. PMID:27433065

  16. A basic study of some normoxic polymer gel dosimeters

    De Deene, Y. [Centre for Medical, Health and Environmental Physics, Queensland University of Technology (Australia) and Radiotherapy Department, Ghent University Hospital, Gent (Belgium)]. E-mail: y.dedeene@qut.edu.au; Hurley, C.; Venning, A.; Mather, M.; Baldock, C. [Centre for Medical, Health and Environmental Physics, Queensland University of Technology (Australia); Vergote, K. [Radiotherapy Department, Ghent University Hospital, Gent (Belgium); Healy, B.J. [Department for Radiotherapy, QRI Mater Centre, Brisbane (Australia)

    2002-10-07

    Polymer gel dosimeters offer a wide range of potential applications in the three-dimensional verification of complex dose distribution such as in intensity-modulated radiotherapy (IMRT). Until now, however, polymer gel dosimeters have not been widely used in the clinic. One of the reasons is that they are difficult to manufacture. As the polymerization in polymer gels is inhibited by oxygen, all free oxygen has to be removed from the gels. For several years this was achieved by bubbling nitrogen through the gel solutions and by filling the phantoms in a glove box that is perfused with nitrogen. Recently another gel formulation was proposed in which oxygen is bound in a metallo-organic complex thus removing the problem of oxygen inhibition. The proposed gel consists of methacrylic acid, gelatin, ascorbic acid, hydroquinone and copper(II)sulphate and is given the acronym MAGIC gel dosimeter. These gels are fabricated under normal atmospheric conditions and are therefore called 'normoxic' gel dosimeters. In this study, a chemical analysis on the MAGIC gel was performed. The composition of the gel was varied and its radiation response was evaluated. The role of different chemicals and the reaction kinetics are discussed. It was found that ascorbic acid alone was able to bind the oxygen and can thus be used as an anti-oxidant in a polymer gel dosimeter. It was also found that the anti-oxidants N-acetyl-cysteine and tetrakis(hydroxymethyl)phosphonium were effective in scavenging the oxygen. However, the rate of oxygen scavenging is dependent on the anti-oxidant and its concentration with tetrakis(hydroxymethyl)phosphonium being the most reactive anti-oxidants. Potentiometric oxygen measurements in solution provide an easy way to get a first impression on the rate of oxygen scavenging. It is shown that cupper(II)sulphate operates as a catalyst in the oxidation of ascorbic acid. We, therefore, propose some new normoxic gel formulations that have a less

  17. A basic study of some normoxic polymer gel dosimeters

    Polymer gel dosimeters offer a wide range of potential applications in the three-dimensional verification of complex dose distribution such as in intensity-modulated radiotherapy (IMRT). Until now, however, polymer gel dosimeters have not been widely used in the clinic. One of the reasons is that they are difficult to manufacture. As the polymerization in polymer gels is inhibited by oxygen, all free oxygen has to be removed from the gels. For several years this was achieved by bubbling nitrogen through the gel solutions and by filling the phantoms in a glove box that is perfused with nitrogen. Recently another gel formulation was proposed in which oxygen is bound in a metallo-organic complex thus removing the problem of oxygen inhibition. The proposed gel consists of methacrylic acid, gelatin, ascorbic acid, hydroquinone and copper(II)sulphate and is given the acronym MAGIC gel dosimeter. These gels are fabricated under normal atmospheric conditions and are therefore called 'normoxic' gel dosimeters. In this study, a chemical analysis on the MAGIC gel was performed. The composition of the gel was varied and its radiation response was evaluated. The role of different chemicals and the reaction kinetics are discussed. It was found that ascorbic acid alone was able to bind the oxygen and can thus be used as an anti-oxidant in a polymer gel dosimeter. It was also found that the anti-oxidants N-acetyl-cysteine and tetrakis(hydroxymethyl)phosphonium were effective in scavenging the oxygen. However, the rate of oxygen scavenging is dependent on the anti-oxidant and its concentration with tetrakis(hydroxymethyl)phosphonium being the most reactive anti-oxidants. Potentiometric oxygen measurements in solution provide an easy way to get a first impression on the rate of oxygen scavenging. It is shown that cupper(II)sulphate operates as a catalyst in the oxidation of ascorbic acid. We, therefore, propose some new normoxic gel formulations that have a less complicated chemical

  18. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    Sen, Swati; Kundagrami, Arindam

    2015-12-01

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  19. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton’s law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization

  20. Reversible adsorption of calcium ions by imprinted temperature sensitive gels

    Alvarez-Lorenzo, Carmen; Guney, Orhan; Oya, Taro; Sakai, Yasuzo; Kobayashi, Masatoshi; Enoki, Takashi; Takeoka, Yukikazu; Ishibashi, Toru; Kuroda, Kenichi; Tanaka, Kazunori; Wang, Guoqiang; Grosberg, Alexander Yu.; Masamune, Satoru; Tanaka, Toyoichi

    2001-02-01

    With the aim of developing polymeric gels sensitive to external stimuli and able to reversibly adsorb and release divalent ions, copolymer gels of N-isopropylacrylamide (NIPA) and methacrylic (MAA) monomers were prepared. We chose calcium as a target divalent ion. Two MAAs form a complex with a calcium ion, and the NIPA component allows the polymers to swell and shrink reversibly in response to temperature. The adsorbing site develops an affinity to target ions when the adsorbing molecules come into proximity, but when they are separated, the affinity diminishes. To enhance the affinity to calcium, an imprinting technique was applied using Ca2+ and Pb2+ ions as templates in methylsulfoxide and dioxane media, respectively. The adsorption capacity of the imprinted gels was compared with that of the nonimprinted gels, and the effects of the templates, the solvents, and the amount of methacrylic monomers used in the synthesis and the medium temperature over the Ca2+ adsorption capacity of the gels from aqueous solutions were evaluated. The analysis of the adsorption revealed that (a) the adsorption can be described by the Langmuir isotherms; (b) there is an approximately linear relationship between saturation and methacrylic monomer concentration; (c) the affinity depends on the degree of gel swelling or shrinkage that can be switched on and off by temperature; (d) in the shrunken state, the affinity depends approximately linearly on the MAA concentration in the imprinted gels, whereas in the nonimprinted gels it is proportional to the square of MAA concentration; (e) the imprinted gels adsorb more than the nonimprinted gels when MAA concentration is less than that of permanent cross linkers. The success of imprinting of CaMAA2 and PbMAA2 complex is evidence for memory of such complex onto the weakly cross-linked gel.

  1. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    Sen, Swati; Kundagrami, Arindam, E-mail: arindam@iiserkol.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, West Bengal (India)

    2015-12-14

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton’s law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  2. Radiological properties of MAGIC normoxic polymer gel dosimetry

    For a polymer gel dosimeter to be of use in radiation dosimetry, it should display water-equivalent radiological properties. In this study, the radiological properties of the MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper) normoxic polymer gels were investigated. The mass density (ρ) was determined based on Archimedes' principle. The weight fraction of elemental composition and the effective atomic number (Zeff) were calculated. The electron density was also measured with 90° scattering angle at room temperature. The linear attenuation coefficient (μ) of unirradiated gel, irradiated gel, and water were determined using Am-241 based on narrow beam geometry. Monte Carlo simulation was used to calculate the depth doses response of MAGIC gel and water for 6MV photon beam. The weight fractions of elements composition of MAGIC gel were close to that for water. The mass density was found to be 1027 ± 2 kg m−3, which is also very close to mass density of muscle tissue (1030 kg m−3) and 2.7% higher than that of water. The electron density (ρe) and atomic number (Zeff) were found to be 3.43 × 1029 e m−3 and 7.105, respectively. The electron density measured was 2.6% greater than that for water. The atomic number was very close to that for water. The prepared MAGIC gel was found to be water equivalent based on the study of element composition, mass density, electron density and atomic number. The linear attenuation coefficient of unirradiated gel was very close to that of water. The μ of irradiated gel was found to be linear with dose 2-40 Gy. The depth dose response for MAGIC gel from a 6 MV photon beam had a percentage dose difference to water of less than 1%. Therefore it satisfies the criteria to be a good polymer gel dosimeter for radiotherapy.

  3. Novel macroporous amphoteric gels: Preparation and characterization

    S. Kudaibergenov

    2012-05-01

    Full Text Available Macroporous amphoteric gels based on allylamine, methacrylic acid and acrylamide crosslinked by N,N'-methylenebisacrylamide were synthesized by radical copolymerization of monomers in cryoconditions. The composition of cryogels was determined by combination of potentiometric and conductimetric titrations. The morphology of cryogels was evaluated by scanning electron microscope (SEM. Cryogels exhibited sponge-like porous structure with pore size ranging from 50 to 200 μm. The values of the isoelectric points (IEPs determined from the swelling experiments arranged between 3.5 and 4.3. The high adsorption-desorption capacity of amphoteric cryogels with respect to mM and trace concentrations of copper, nickel, and cobalt ions was demonstrated. It was shown that the macroporous amphoteric cryogels are able to adsorb up to 99.9% of copper, nickel, and cobalt ions from 10–3 mol•L–1 aqueous solution.

  4. The Gelså River Restoration Revisited

    Friberg, Nikolai; Baattrup-Pedersen, Annette; Kristensen, Esben; Kronvang, Brian; Larsen, Søren Erik; Pedersen, Morten Lauge; Skriver, Jens; Thodsen, Hans; Wiberg-Larsen, Peter

    2014-01-01

    The study was undertaken on the River Gelså, Denmark, where a 1.8 km meandering course was estab-lished in 1989 to replace a channelized river reach. This restoration project was the first of its kind inDenmark and has the longest time-series of post-intervention data of any restoration project...... conductedworld-wide. Additionally, a 0.5 km upstream (control) reach that remained channelized has been sampledsince 1989. In this paper, we examined macroinvertebrate assemblages in distinct habitats in 2008, 19years after the restoration, and community persistence between two years, 1997 and 2008, to...... investigatethe longer-term effects of restoration on the biota. We found that habitat type influenced macroinverte-brate community composition to some degree, while there were no clear effects on - and -diversity ofhabitat or reach type. Stony substrate habitats introduced as part of the restoration could...

  5. Photoluminescence of sol-gel-prepared hafnia

    Kiisk, Valter, E-mail: kiisk@ut.e [Institute of Physics, University of Tartu, Riia Str. 142, 51014 Tartu (Estonia); Lange, Sven; Utt, Kathriin; Taette, Tanel; Maendar, Hugo; Sildos, Ilmo [Institute of Physics, University of Tartu, Riia Str. 142, 51014 Tartu (Estonia)

    2010-01-15

    We employed a sol-gel route followed by a thermal treatment (up to 1000 deg. C) to prepare crystalline (monoclinic) hafnium dioxide. Thorough steady-state and time-resolved photoluminescence characterization of the material within the temperature range of 10-300 K was conducted by using various excitation sources. The most prominent spectroscopic feature of the material was an intense broad emission band centered at 2.3-2.5 eV with an associated excitation band centered at 4.2-4.4 eV (well below the bandgap of monoclinic hafnia). The emission was characterized by an essentially non-exponential, thermally stimulated decay and exposed a marked blue shift with the increase of temperature from 10 to 300 K. Relation of the emission to the intrinsic defects of hafnia is discussed.

  6. Electrochemistry of polyamidoamine dendrimers ester gel electrolytes

    CHEN Hong; MO Zunli

    2004-01-01

    This paper described the first example of polyamidoamine dendrimers ester (PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as a plasticizer. The polymer films are solid and sticky. Background cyclic voltammetry (CV) shows a potential window between +0.7 and -0.7 V vs. Ag/AgCl. The voltammetry of ferrocene and 7,7,8,8-tetracyanoquinodimethane (TCNQ) indicates that diffusion coefficients are in the range of 10-a-10-9 cm2/s.Ionic conductivities are approximately 10-6 S/cm. Similar films using dimethyl sulfoxide (DMSO) as a plasticizer instead of MPEG-400 have demonstrated ionic conductivities of 10-4 S/cra and reversible voltammetry. However, UV spectrophotometry shows that 70% of the DMSO is lost under vacuum, indicating the difficulty in quantifying the DMSO content when exposed to vacuum.

  7. How to scan polymer gels with MRI?

    De Deene, Y.

    2013-06-01

    The absorbed radiation dose fixated in a polymer gel dosimeter can be read out by several methods such as magnetic resonance imaging (MRI), optical CT, X-ray CT and ultrasound with MRI being the first method that was explored. Although MRI was considered as an elegant scanning technique, readily available in most hospitals, it was later found that using a non-optimized imaging protocol may result in unacceptable deviations in the obtained dose distribution. Although most medical physicists have an understanding of the basic principles of magnetic resonance imaging (MRI), the optimization of quantitative imaging sequences and protocols is often perceived as the work of MRI experts. In this paper, we aim at providing the reader with some easy guidelines in how to obtain reliable quantitative MRI maps.

  8. Clotrimazole nanoparticle gel for mucosal administration

    Esposito, Elisabetta, E-mail: ese@unife.it [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Ravani, Laura [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Contado, Catia [Department of Chemistry, University of Ferrara, Ferrara (Italy); Costenaro, Andrea [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Drechsler, Markus [Macromolecular Chemistry II, University of Bayreuth (Germany); Rossi, Damiano [Department of Biology and Evolution, LT Terra and Acqua Tech UR7, University of Ferrara, Ferrara (Italy); Menegatti, Enea [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Grandini, Alessandro [Department of Biology and Evolution, LT Terra and Acqua Tech UR7, University of Ferrara, Ferrara (Italy); Cortesi, Rita [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy)

    2013-01-01

    In this study a formulation suitable to be applied on oral and/or vaginal mucosa has been developed for the treatment of fungal infections. The aim of the research is a comparison between clotrimazole (CLO) containing semisolid formulations based on monoolein aqueous dispersion (MAD) or nanostructured lipid carrier (NLC). MAD and NLC have been characterized in terms of morphology and dimensional distribution by cryogenic Transmission Electron Microscopy (cryo-TEM) and Photon Correlation Spectroscopy (PCS). CLO was encapsulated with high entrapment efficiency both in MAD and in NLC, according to Sedimentation Field Flow Fractionation (SdFFF) combined with HPLC. CLO recovery in MAD and NLC has been investigated by time. In order to obtain formulations with suitable viscosity for mucosal application, MAD was diluted with a carbomer gel, while NLC was directly viscosized by the addition of poloxamer 407 in the dispersion. The rheological properties of MAD and NLC after viscosizing have been investigated. Franz cell has been employed to study CLO diffusion from the different vehicles, evidencing diffusion rates from MAD and NLC superimposable to that obtained using Canesten{sup Registered-Sign }. An anticandidal activity study demonstrated that both CLO-MAD and CLO-NLC were more active against Candida albicans with respect to the pure drug. Highlights: Black-Right-Pointing-Pointer Comparison between monoolein aqueous dispersion (MAD) and nanostructured lipid carrier (NLC). Black-Right-Pointing-Pointer Clotrimazole (CLO) encapsulated with high entrapment efficiency both in MAD and in NLC. Black-Right-Pointing-Pointer The solid matrix of NLC controls CLO degradation better than MAD. Black-Right-Pointing-Pointer CLO containing MAD and NLC exhibits a higher anticandidal activity than the free drug. Black-Right-Pointing-Pointer Simple production of CLO-NLC based poloxamer gel, suitable for industry scaling up.

  9. Modelling of erosion of bentonite gel by gel/sol flow

    Moreno, Luis; Neretnieks, Ivars; Longcheng Liu (Chemical Engineering and Technology, School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm (Sweden))

    2010-11-15

    Bentonite intrusion into a fracture intersecting the canister deposition hole is modelled. The model describes the expansion of the bentonite within the fracture. It accounts for the repulsive electrostatic double-layer forces, the attractive van der Waals forces and friction forces between the particles and the water. The model also takes into account the diffusion of the colloid particles in the smectite sol. Diffusion of a counterion, sodium, is accounted for as this strongly influences the double layer force and the viscosity of the gel/sol. The gel/sol is considered to be a fluid with a varying viscosity that is strongly dependent on the bentonite volume fraction in the gel and the sodium concentration in the water. Two different geometries were modelled; a rectangular and a cylindrical. The rectangular geometry was used to gain experience with the processes and mechanisms and how they interact since the cylindrical geometry was somewhat less stable numerically and more time consuming. In the rectangular geometry a fracture 1 metre long in the flow direction was modelled. In both geometries the fracture size was selected sufficiently large to ensure that the water velocity, near the distant border was nearly the same as the approaching water velocity and that the smectite concentration there was vanishingly small. It was found that the velocity of the fluid drops considerably where the bentonite volume fraction is larger than 1-2%. This is due to the strong increase in viscosity with increasing bentonite volume fraction. The loss of smectite by the slowly flowing fluid was found to be proportional to the square root of the seeping water velocity for the rectangular geometry. For the cylindrical geometry, the dependence is somewhat lower (exponent about 0.4) since the length of the gel/water interface decreases with increasing water flow rate. The penetration depth of the gel/water interface decreases with increasing water flow rate. For water velocity of the

  10. Modelling of erosion of bentonite gel by gel/sol flow

    Bentonite intrusion into a fracture intersecting the canister deposition hole is modelled. The model describes the expansion of the bentonite within the fracture. It accounts for the repulsive electrostatic double-layer forces, the attractive van der Waals forces and friction forces between the particles and the water. The model also takes into account the diffusion of the colloid particles in the smectite sol. Diffusion of a counterion, sodium, is accounted for as this strongly influences the double layer force and the viscosity of the gel/sol. The gel/sol is considered to be a fluid with a varying viscosity that is strongly dependent on the bentonite volume fraction in the gel and the sodium concentration in the water. Two different geometries were modelled; a rectangular and a cylindrical. The rectangular geometry was used to gain experience with the processes and mechanisms and how they interact since the cylindrical geometry was somewhat less stable numerically and more time consuming. In the rectangular geometry a fracture 1 metre long in the flow direction was modelled. In both geometries the fracture size was selected sufficiently large to ensure that the water velocity, near the distant border was nearly the same as the approaching water velocity and that the smectite concentration there was vanishingly small. It was found that the velocity of the fluid drops considerably where the bentonite volume fraction is larger than 1-2%. This is due to the strong increase in viscosity with increasing bentonite volume fraction. The loss of smectite by the slowly flowing fluid was found to be proportional to the square root of the seeping water velocity for the rectangular geometry. For the cylindrical geometry, the dependence is somewhat lower (exponent about 0.4) since the length of the gel/water interface decreases with increasing water flow rate. The penetration depth of the gel/water interface decreases with increasing water flow rate. For water velocity of the

  11. Characterization of a humic gel synthesized from an activated epoxy silica gel

    Purified humic acid has been covalently bound on activated epoxy silica gel particles. Determination of physical properties and chemical properties was conducted in order to characterize the material at different stages of the preparation. FTIR spectra and the PEC of the surface bound humic acid is very similar to that of humic acid starting material. This shows that the humic acid was not deteriorated during the surface binding process. This humic gel can be used as an analogue for sediment associated humic acid, with the advantage that covalently bound humic acid does not desorb, and thus allows for simple species separation between non-complexed and humic bound metal ions in batch and column experiments

  12. Transfer printing of thermoreversible ion gels for flexible electronics.

    Lee, Keun Hyung; Zhang, Sipei; Gu, Yuanyan; Lodge, Timothy P; Frisbie, C Daniel

    2013-10-01

    Thermally assisted transfer printing was employed to pattern thin films of high capacitance ion gels on polyimide, poly(ethylene terephthalate), and SiO2 substrates. The ion gels consisted of 20 wt % block copolymer poly(styrene-b-ethylene oxide-b-styrene and 80 wt % ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)amide. Patterning resolution was on the order of 10 μm. Importantly, ion gels containing the block polymer with short PS end blocks (3.4 kg/mol) could be transfer-printed because of thermoreversible gelation that enabled intimate gel-substrate contact at 100 °C, while gels with long PS blocks (11 kg/mol) were not printable at the same temperature due to poor wetting contact between the gel and substrates. By using printed ion gels as high-capacitance gate insulators, electrolyte-gated thin-film transistors were fabricated that operated at low voltages (<1 V) with high on/off current ratios (∼10(5)). Statistical analysis of carrier mobility, turn-on voltage, and on/off ratio for an array of printed transistors demonstrated the excellent reproducibility of the printing technique. The results show that transfer printing is an attractive route to pattern high-capacitance ion gels for flexible thin-film devices. PMID:24028461

  13. Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials

    Ens, S.; Olson, A. B.; Dudley, C.; Ross, N. D., III; Siddiqi, A. A.; Umoh, K. M.; Schneegurt, M. A.

    2012-01-01

    Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic…

  14. Self-Healing Corrosion Protective Sol-Gel Coatings

    Abdolah Zadeh, M.

    2016-01-01

    Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic heali

  15. Separation of Protein Oligomers by Blue Native Gel Electrophoresis

    Braz, Valerie A.; Howard, Kathryn J.

    2009-01-01

    Native gel electrophoresis is used as a tool to assess structural differences in proteins. This note presents an application to separate oligomeric forms of proteins, such as HIV-1 reverse transcriptase monomers and homodimers. Technical difficulties encountered with various native gel techniques and ways to circumvent them are described.

  16. Gel Electrophoresis--The Easy Way for Students

    VanRooy, Wilhelmina; Sultana, Khalida

    2010-01-01

    This article describes a simple, inexpensive, easy to conduct gel-electrophoresis activity using food dyes. It is an alternative to the more expensive counterparts which require agarose gel, DNA samples, purchased chamber and Tris-borate-EDTA buffer. We suggest some learning activities for senior biology students along with comments on several…

  17. Physical gels based on charge-driven co-assembly

    Lemmers, M.

    2012-01-01

    Gels are used in a variety of products ranging from personal care products and food products to explosives. An important area where aqueous physical gels are applied is the water-based coatings industry. Currently, classical associative thickeners are used to form transient networks based on hydroph

  18. Compensation Of Smile Effect Distortion In Electrophoretic Gel Image

    Dvořáček, T.

    2015-01-01

    This paper is engaged in the issue of automatic detection and removal of smile effect geometrical distortion in agarose gel electrophoresis images. Based on created databank of electrophoretic phantoms, an algorithm that is able to repair mentioned smile effect distortion was created. In this paper, two gel images with applied removal algorithm are shown with percentage description of reparation level.

  19. A comparative study of new type polymer gel dosimeters

    In this study we have investigated and evaluated some dosimetric properties of polymer gel dosimeter encountered when using gels in clinical radiation therapy environment. Four different compositions of polymer gel dosimeter were manufactured. Two compositions (A and D) represent widely recognized gels prepared following literature instructions. In case of MAGIC type dosimeter (D), gelatin weight fraction was decreased to 5%. During our previous research, we have experienced some substantial changes in behavior when lowering amount of sodium hydroxide and when potassium aluminum sulfate was added. Therefore another two gels were prepared (B and C). Gel dosimeters were evaluated using transversal relaxation rate R2. Details of the used acquisition sequence may be found in Spevacek V. et.al. (2001), only eight echo times were used for R2 calculation in this case. The following properties have been investigated for the four gel compositions: dose response; temperature dependence of dose response; short and long term stability; behavior of gels in a region of steep dose gradient; and uniformity of homogeneously irradiated region. (authors)

  20. Comparison of Two Types of Gels in Improving Burn Wound

    Rahimzadeh Golnar

    2014-01-01

    Full Text Available Objective: Kefir are natural probiotic compounds with anti-inflammatory properties, which were tested in experimental burn injury. Kefir gels were prepared from an extract of continuously cultured kefir in Man, Rogosa and Sharpe Broth medium for 48 and 96 h. Their extracts were used for evaluation of antibacterial effect against Pseudomonas aeruginosa in standard sample (ATCC 27853 and samples taken from patients with burns. The antibacterial effect of different kefir extract was assessment of minimum inhibitory concentration and minimum bactericidal concentration. The density of bacteria and percentage of organic acids (lactic and acetic acids were also determined. Materials and Methods: Similar burn injuries were made on dorsal skin surface of 40 rats. The rats were divided into 5 groups of 8 rats each. The base gel, silver sulfadiazine ointment, kefir 48 h gel, kefir 96 h gel were applied twice daily. Burn wound area was measured at baseline, 1 and 2 weeks. Results: Results indicated that by increasing the time of fermentation, concentration of lactic and acetic acid increased in orders of: Kefir 48 h < kefir 96 h, the end of the 2nd week the percentage of wound size were lowest in order of kefir 96 h gel < kefir grains 48 h gel < silver sulfadiazine 1% < untreated and based gel groups. Conclusion: In conclusion, the kefir gel therapy was an effective therapeutic approach to improve outcomes after severe burn when compared with conventional silver sulfadiazine treatment.

  1. SYNTHESIS OF HIGH THERMOSTABLE SILICONE GELS CONSTRUCTED WITH LADDERLIKE POLYSILSESQUIOXANES

    Huai-zhong Pan; Ming Cao; Jian-hua Luo; Ping Xie; Rong-ben Zhang; Yu-hui Lin; Neal Tai-sheng Chung

    2000-01-01

    Heat-resistant silicone gels were synthesized by replacing the single main chain polymethylhydrosiloxane with reactive ladderlike polyhydrosilsesquioxane copolymers. Because of the interaction between polydimethylsiloxane chains and the ladderlike polysilsesquioxanes chains, the cyclization of the polydimethylsiloxane chains is hindered. The high thermal stability of the ladderlike polymers can improve the thermal stability of the silicone gels without sacrificing their good comprehensive properties.

  2. Maintenance of Bacterial Cultures on Anhydrous Silica Gel

    Lennox, John E.

    1977-01-01

    Suspensions of 20 different cultures were grown on appropriate media, then pipetted into sterile anhydrous silica gel. Silica gel cultures after incubation and refrigerated storage were tested for viability. Results showed little mutation, low replication, low contamination, minimal expenses, and survival up to two years. (CS)

  3. Spectroscopic studies of triethoxysilane sol-gel and coating process

    Li, Ying-Sing; Ba, Abdul

    2008-10-01

    Silica sol-gels have been prepared under different conditions using triethoxysilane (TES) as precursor. The prepared sol-gels have been used to coat aluminum for corrosion protection. Vibrational assignments have been made for most vibration bands of TES, TES sol-gel, TES sol-gel-coated aluminum and xerogel. It has been noticed that air moisture may have helped the hydrolysis of the thin coating films. Xerogels have been obtained from the sol-gel under different temperature conditions and the resulting samples have been characterized by using infrared and Raman spectroscopic methods. IR data indicate that the sol-gel process is incomplete under the ambient conditions although an aqueous condition can have slightly improved the process. Two nonequivalent silicon atoms have been identified from the collected 29Si NMR spectra for the sol-gel, supporting the result derived from the IR data. The frequency of Si sbnd H bending vibration has been found to be more sensitive to the skeletal structure than that of the Si sbnd H stretching vibration. A higher temperature condition could favor the progression of hydrolysis and condensation. A temperature higher than 300 °C would cause sample decomposition without seriously damaging the silica network. From infrared intensity measurements and thermo-gravimetric analyses, the fractions of incomplete hydrolysis and condensation species have been estimated to be 4% and 3%, respectively. Electrochemical data have shown that the sol-gel coating significantly improves the corrosion protection properties of aluminum.

  4. Multiresponsive Reversible Gels Based on Charge-Driven Assembly

    Lemmers, Marc; Sprakel, Joris; Voets, Ilja K.; van der Gucht, Jasper; Stuart, Martien A. Cohen

    2010-01-01

    Coassembly of an ABA triblock copolymer with charged end blocks and an oppositely charged polyelectrolyte yields gels that respond to changes in concentration, temperature, ionic strength, pH value, and charge composition. Above the critical gel concentration, the triblock copolymers bridge micelles, forming a sample-spanning transient network of interconnected micelles.

  5. Gravitational collapse of depletion-induced colloidal gels.

    Harich, R; Blythe, T W; Hermes, M; Zaccarelli, E; Sederman, A J; Gladden, L F; Poon, W C K

    2016-05-11

    We study the ageing and ultimate gravitational collapse of colloidal gels in which the interparticle attraction is induced by non-adsorbing polymers via the depletion effect. The gels are formed through arrested spinodal decomposition, whereby the dense phase arrests into an attractive glass. We map the experimental state diagram onto a theoretical one obtained from computer simulations and theoretical calculations. Discrepancies between the experimental and simulated gel regions in the state diagram can be explained by the particle size and density dependence of the boundary below which the gel is not strong enough to resist gravitational stress. Visual observations show that gravitational collapse of the gels falls into two distinct regimes as the colloid and polymer concentrations are varied, with gels at low colloid concentrations showing the onset of rapid collapse after a delay time. Magnetic resonance imaging (MRI) was used to provide quantitative, spatio-temporally resolved measurements of the solid volume fraction in these rapidly collapsing gels. We find that during the delay time, a dense region builds up at the top of the sample. The rapid collapse is initiated when the gel structure is no longer able to support this dense layer. PMID:27001686

  6. Biocatalysis with Sol-Gel Encapsulated Acid Phosphatase

    Kulkarni, Suhasini; Tran, Vu; Ho, Maggie K.-M.; Phan, Chieu; Chin, Elizabeth; Wemmer, Zeke; Sommerhalter, Monika

    2010-01-01

    This experiment was performed in an upper-level undergraduate biochemistry laboratory course. Students learned how to immobilize an enzyme in a sol-gel matrix and how to perform and evaluate enzyme-activity measurements. The enzyme acid phosphatase (APase) from wheat germ was encapsulated in sol-gel beads that were prepared from the precursor…

  7. Dynamical transition of heat transport in a physical gel near the sol-gel transition

    Kobayashi, Kazuya U.; Noriko Oikawa; Rei Kurita

    2015-01-01

    We experimentally study heat transport in a gelatin solution near a reversible sol-gel transition point where viscosity strongly depends on temperature. We visualize the temperature field and velocity field using thermochromic liquid crystals and polystyrene latex particles, respectively. During the initial stages of heating, we find that heat transport undergoes a dynamical transition from conductive to convective. Subsequently, during later stages, we observe that the transport dynamics are...

  8. Formulation of Niosomal Gel for Enhanced Transdermal Lopinavir Delivery and Its Comparative Evaluation with Ethosomal Gel

    Patel, Ketul K.; Kumar, Praveen; Thakkar, Hetal P.

    2012-01-01

    The aim was to develop niosomal gel as a transdermal nanocarrier for improved systemic availability of lopinavir. Niosomes were prepared using thin-film hydration method and optimized for molar quantities of Span 40 and cholesterol to impart desirable characteristics. Comparative evaluation with ethosomes was performed using ex vivo skin permeation, fluorescence microscopy, and histopathology studies. Clinical utility via transdermal route was acknowledged using in vivo bioavailability study ...

  9. Origin of water loss from soy protein gels.

    Urbonaite, V; de Jongh, H H J; van der Linden, E; Pouvreau, L

    2014-07-30

    Water holding (WH) of soy protein gels was investigated to identify which length scales are most contributing to WH when centrifugal forces are applied. More specifically, it was attempted to differentiate between the contributions of submicron and supramicron length scales. MgSO4 and MgCl2 salt specificities on soy protein aggregation (submicron contribution) were used to create different gel morphologies (supramicron contribution). Obtained results showed that the micrometer length scale is the most important contribution to WH of gels under the applied deformation forces. WH of soy protein gels correlated negatively with Young's modulus and positively with recoverable energy. The occurrence of rupture events had only a limited impact on WH. The ease by which water may be removed from the gel, but not the total amount, seemed to be related to the initial building block size. These insights could be exploited in product development to predict and tune oral perception properties of (new) products. PMID:24972135

  10. Laser CT evaluation on normoxic PAGAT gel dosimeter

    Kumar, D. S.; Samuel, E. J. J.; Watanabe, Y.

    2013-06-01

    Optical computed tomography has been shown to be a potentially useful imaging tool for the radiation therapy physicists. In radiation therapy, researchers have used optical CT for the readout of 3D dosimeters. The purpose of this paper is to describe the initial evaluation of a newly fabricated laser CT scanner for 3D gel dosimetry which works using the first generation principle. A normoxic PAGAT (Polyacrylamide Gelatin and Tetrakis) gel is used as a dosimeter for this analysis. When a laser passes through the gel phantom, absorption and scattering of photon take place. The optical attenuation coefficient of the laser can be obtained by measuring its intensity after passing through the gel by a sensor. The scanner motion is controlled by a computer program written in Microsoft Visual C++. Reconstruction and data analysis on the irradiated gel phantom is performed by suitable algorithm using Matlab software.

  11. The Applications of Shape Memory Gel as a Smart Material

    Hasnat Kabir, M.; Gong, Jin; Watanabe, Yosuke; Makino, Masato; Furukawa, Hidemitsu

    The research to find a suitable future new material is a big challenge nowadays. The material for biocompatible or biodegradable is an important issue in human life. The environment friendly materials or in other words green materials are required for future applications. The gels are soft and wet material having several unique properties such as high water absorbent, extremely low friction, softness, shape memory, high ductility and so on. The gel consists with a large amount of solvent and a small amount of cross-linker. Due to the high water content, for instants, more than 90%, this material becomes as an environment friendly green material. The shape memory gel (SMG) is one kind of soft materials among them which bears some interesting characteristics. This gel, a smart material, can be used as lens, eyeball, artificial muscle or artificial blood vessel, smart button and so on. In this paper, we have briefly discussed the different applications of the shape memory gel.

  12. Viscoelastic nature of Au nanoparticle–PDMS nanocomposite gels

    Ritu Gupta; Hima K Nagamanasa; Rajesh Ganapathy; Giridhar U Kulkarni

    2015-08-01

    A stable gel of Au nanoparticles in polydimethylsiloxane (PDMS) nanocomposite is prepared by employing the curing agent of PDMS elastomer as a reducing agent for the formation of Au nanoparticles by an in-situ process. The viscoelastic nature of these gels is very sensitive to the Au nanoparticle loading and the synthetic temperature conditions. Even a very low Au content of 0.09 wt% is sufficient enough to bring in the transition from sponge state to gel state at room temperature. Higher synthetic temperature also forms sponge formation. Infrared and ultraviolet–visible spectroscopy measurements have provided insight into PDMS crosslinking and nanoparticle formation, respectively. The optimization of the gel properties can have direct influence on the processability of Au nanoparticle–PDMS nanocomposite gels, with interesting implications in electronic, optical and microfluidic devices.

  13. [Biocompatibility analysis of hyaluronic acid sodium gels for medical application].

    Wang, Yaning; Yuan, Tun; Jia, Lifang; Zou, Wen; Liang, Jie

    2012-08-01

    Hyaluronan acid sodium gels are used in ophthalmic surgery, orthopedic treatment and cosmetic surgery. In 2009,there were 12 domestic manufacturers in China producing 33 kinds of products. 23 kinds of imported products were allowed by SFDA to sale in the meantime. Since manufacturers use different production processes, product performances are quite different. According to the GB/T 16886. 1-2001, we designed a pilot program to evaluate the sodium hyaluronate gel products comprehensively in this paper. The results showed that, except chromosome aberration test of gel A and subchronic systemic toxicity of gel C appeared positive, the remaining samples of the test results were negative. This article provides a reference to write standard of cross-linked hyaluronic sodium gel and the revision of standard YY0308-2004. PMID:23016423

  14. Molecular Gels Materials with Self-Assembled Fibrillar Networks

    Weiss, Richard G

    2006-01-01

    Molecular gels and fibrillar networks – a comprehensive guide to experiment and theory Molecular Gels: Materials with Self-Assembled Fibrillar Networks provides a comprehensive treatise on gelators, especially low molecular-mass gelators (LMOGs), and the properties of their gels. The structures and modes of formation of the self-assembled fibrillar networks (SAFINs) that immobilize the liquid components of the gels are discussed experimentally and theoretically. The spectroscopic, rheological, and structural features of the different classes of LMOGs are also presented. Many examples of the application of the principal analytical techniques for investigation of molecular gels (including SANS, SAXS, WAXS, UV-vis absorption, fluorescence and CD spectroscopies, scanning electron, transmission electron and optical microscopies, and molecular modeling) are presented didactically and in-depth, as are several of the theories of the stages of aggregation of individual LMOG molecules leading to SAFINs. Several actua...

  15. The Chemistry and Applications of π-Gels

    Ghosh, Samrat; Praveen, Vakayil K.; Ajayaghosh, Ayyappanpillai

    2016-07-01

    π-Gels are a promising class of functional soft materials formed out of short π-conjugated molecules. By utilizing the chemistry of noncovalent interactions, researchers have created a wide range of π-gels that are composed of supramolecular polymers. During the last two decades, supramolecular gel chemistry has been pursued with the hope of developing new materials for applications in, for example, organic electronics, energy harvesting, sensing, and imaging. The high expectations for π-gels were centered mainly around their electronic properties, such as tunable emission, energy transfer, electron transfer, charge transport, and electrical conductivity; such properties are amenable to modulation through size and shape control of molecular assemblies. Although a large number of exciting publications have appeared, a major technological breakthrough is yet to be realized. In this review, we analyze the recent advancements in the area of functional π-gels and their scope in future applications.

  16. Oscillatory and electrohydrodynamic instabilities in flow over a viscoelastic gel

    R M Thaokar

    2015-05-01

    The stability of oscillatory flows over compliant surfaces is studied analytically and numerically. The type of compliant surfaces studied is the incompressible viscoelastic gel model. The stability is determined using the Floquet analysis, where amplitude of perturbations at time intervals separated by one time period is examined to determine whether perturbations grow or decay. Oscillatory flows pas viscoelastic gels exhibit an instability in the limit of zero Reynolds number, and the transition amplitude of the oscillatory velocity increases with the frequency of oscillations. The transition amplitude has a minimum at a finite wavenumber for the viscoelastic gel model. The instability is found to depend strongly on the gel viscosity $\\eta_{g}$, and the effect of oscillations on the continuation of viscous modes at intermediate Reynolds number shows a complicated dependence on the oscillation frequency. Experimental studies are carried out on the stability of an oscillatory flow past a viscoelastic gel at zero Reynolds number, and these confirm the theoretical predictions.

  17. Volume phase transitions of cholesteric liquid crystalline gels

    Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp [Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502 (Japan)

    2015-05-07

    We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.

  18. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    S S Sekhon

    2003-04-01

    Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet its effect on the conductivity behaviour of gel electrolytes as well as the interaction of polymer with salt and solvent has not been conclusively established. The conductivity of lithium ion conducting polymer gel electrolytes decreases with the addition of polymer whereas in the case of proton conducting polymer gel electrolytes an increase in conductivity has been observed with polymer addition. This has been explained to be due to the role of polymer in increasing viscosity and carrier concentration in these gel electrolytes.

  19. Processing and characterization of Aloe vera gel for hydrogel preparation

    This work describes the processing and characterization of Aloe vera gel for the preparation of hydrogels through gamma radiation from polymers and natural products in order to be used in biomedical applications. Processing was carried out immersing slices of aloe in distilled water for phenolic compound extraction. Through UV-VIS spectroscopy, 48 hours was determined as the optimal soaking time, at which organoleptic characteristics of the gel as well as its pH were acceptable. An increase of pH was observed on the gel that was stored at room temperature. The non processed gel showed a pink coloration. Results of gel yield values were not high. Microbiological tests showed a high bioburden. (author)

  20. Foam and gel methods for the decontamination of metallic surfaces

    Nunez, Luis; Kaminski, Michael Donald

    2007-01-23

    Decontamination of nuclear facilities is necessary to reduce the radiation field during normal operations and decommissioning of complex equipment. In this invention, we discuss gel and foam based diphosphonic acid (HEDPA) chemical solutions that are unique in that these solutions can be applied at room temperature; provide protection to the base metal for continued applications of the equipment; and reduce the final waste form production to one step. The HEDPA gels and foams are formulated with benign chemicals, including various solvents, such as ionic liquids and reducing and complexing agents such as hydroxamic acids, and formaldehyde sulfoxylate. Gel and foam based HEDPA processes allow for decontamination of difficult to reach surfaces that are unmanageable with traditional aqueous process methods. Also, the gel and foam components are optimized to maximize the dissolution rate and assist in the chemical transformation of the gel and foam to a stable waste form.

  1. Optical and electrochemical sol-gel sensors for inorganic species

    Royce; N.DANSBY-SPARKS

    2009-01-01

    The use of sol-gels as a sensing matrix for the development of unique sensing strategies is discussed.Sol-gels offer almost limitless possibilities for sensing substrates due to the variety of physical properties that can be obtained by altering a number of discussed fabrication conditions and techniques.By careful consideration of the sensing requirements,novel detection methods have been developed for a variety of analytes and applications.Here,sol-gels have been used to monitor pH at the extreme ends of the scale([H+] = 1―11 M and [OH-] = 1―10 M) and in mixed solvent/solute systems using dual sensing approaches.The use of ligand-grafted sol-gel monoliths for optical determination of metal ion species is also discussed.The electrochemical determination of Cr(Ⅵ) by electrodeposited sol-gel modified electrodes is also presented.

  2. Sol-gel materials for optofluidics - process and applications

    Mikkelsen, Morten Bo Lindholm

    2011-01-01

    This Ph.D. thesis is concerned with the use of sol-gel materials in optofluidic applications and the physics of DNA molecules in nanoconfinement. The bottom-up formation of solid material, which is provided by the sol-gel process, enables control of the chemical composition and porosity of the...... material. At early stages of gelation, thin gel coatings can be structured by nanoimprint lithography, and purely inorganic silica materials can be obtained by subsequent thermal annealing. The sol-gel process thus constitutes a unique method for nanofabrication of silica materials of special properties....... In this work, sol-gel silica is introduced as a new material class for the fabrication of lab-on-a-chip devices for DNA analysis. An imprint process with a rigid, non-permeable stamp was developed, which enabled fabrication of micro- and nanofluidic silica channels in a single process step without...

  3. Formulation of niosomal gel for enhanced transdermal lopinavir delivery and its comparative evaluation with ethosomal gel.

    Patel, Ketul K; Kumar, Praveen; Thakkar, Hetal P

    2012-12-01

    The aim was to develop niosomal gel as a transdermal nanocarrier for improved systemic availability of lopinavir. Niosomes were prepared using thin-film hydration method and optimized for molar quantities of Span 40 and cholesterol to impart desirable characteristics. Comparative evaluation with ethosomes was performed using ex vivo skin permeation, fluorescence microscopy, and histopathology studies. Clinical utility via transdermal route was acknowledged using in vivo bioavailability study in male Wistar rats. The niosomal formulation containing lopinavir, Span 40, and cholesterol in a molar ratio of 1:0.9:0.6 possessed optimally high percentage of drug entrapment with minimum mean vesicular diameter. Ex vivo skin permeation studies of lopinavir as well as fluorescent probe coumarin revealed a better deposition of ethosomal carriers but a better release with niosomal carriers. Histopathological studies indicated the better safety profile of niosomes over ethosomes. In vivo bioavailability study in male Wistar rats showed a significantly higher extent of absorption (AUC(0→∞), 72.87 h × μg/ml) of lopinavir via transdermally applied niosomal gel as compared with its oral suspension. Taken together, these findings suggested that niosomal gel holds a great potential of being utilized as novel, nanosized drug delivery vehicle for transdermal lopinavir delivery. PMID:23104306

  4. Primary hepatocyte culture in collagen gel mixture and collagen sandwich

    Ying-Jie Wang; Hong-Ling Liu; Hai-Tao Guo; Hong-Wei Wen; Jun Liu

    2004-01-01

    AIM: To explore the methods of hepatocytes culture in a collagen gel mixture or between double layers of collagen sandwich configuration and to examine the functional and cytomorphological characteristics of cultured hepatocytes.METHODS: A two-step collagenase perfusion technique was used to isolate the hepatocytes from Wistar rats or newborn Chinese experimental piglets. The isolated hepatocytes were cultured in a collagen gel mixture or between double layers of collagen sandwich configuration respectively. The former was that rat hepatocytes were mixed with type I rat tail collagen solution till gelled, and the medium was added onto the gel. The latter was that swine hepatocytes were seeded on a plate precoated with collagen gel for 24 h, then another layer of collagen gel was overlaid, resulting in a sandwich configuration. The cytomorphological characteristics, albumin secretion, and LDH-release of the hepatocytes cultured in these two models were examined.RESULTS: Freshly isolated rat hepatocytes were successfully mixed and fixed in collagen gel, and cultured in the gel condition. During the culture period, the urea synthesized and secreted by rat hepatocytes was detected throughout the period. Likewise, newborn experimental piglet hepatocytes were successfully fixed between the double layers of collagen gel, forming a sandwich configuration.Within a week of culture, the albumin secreted by swine hepatocytes was detected by SDS/PAGE analysis. The typical cytomorphological characteristics of the hepatocytes cultured by the above two culture models were found under a phasecontrast microscope. There was little LDH-release during the culture period.CONCLUSION: Both collagen gel mixture and double layers of collagen sandwich configuration can provide cultural conditions much closer to in vivoenvironment, and are helpful for maintaining specific hepatic fiJnctions and cytomorphological characteristics. A collagen gel mixture culture may be more eligible for the

  5. Fluorescent tetraruthenated porphyrins embedded in monolithic SiO2 gels by the sol-gel process.

    Santos, Shirleny F; Santos, Marcelo L; Almeida, Luis E; Costa, Nivan B; Gimenez, Iara F; Araki, Koiti; Mayer, Ildemar; Engelmann, Fabio Monaro; Toma, Henrique Eisi; Barreto, Ledjane S

    2007-01-15

    In this work silica gels have been prepared by a sol-gel method using tetraethylorthosilicate as gel precursor. The tetraruthenated porphyrins H2(3-TRPyP), Co(3-TRPyP), and H2(4-TRPyP) were incorporated into the systems during gel formation without problems commonly found in the process, such as aggregation. Spectroscopic studies of the resulting silica gels revealed the presence of absorption bands in the range 200-400 nm associated with the transitions of the groups ruthenium-bipyridine, along with the Soret band at the same wavelengths observed in solution. The porphyrins were found to preserve fluorescence emission properties in the range 650-700 nm even after the aging period. Study of the thermal behavior and decomposition kinetics evidenced that the porphyrin H2(4-TRPyP) is the least stable of the group and that all compounds decompose according to first-order kinetics. PMID:17074358

  6. RegStatGel: proteomic software for identifying differentially expressed proteins based on 2D gel images

    Li, Feng; Seillier-Moiseiwitsch, Françoise

    2011-01-01

    Image analysis of two-dimensional gel electrophoresis is a key step in proteomic workflow for identifying proteins that change under different experimental conditions. Since there are usually large amount of proteins and variations shown in the gel images, the use of software for analysis of 2D gel images is inevitable. We developed open-source software with graphical user interface for differential analysis of 2D gel images. The user-friendly software, RegStatGel, contains fully automated as well as interactive procedures. It was developed and has been tested under Matlab 7.01. Availability The database is available for free at http://www.mediafire.com/FengLi/2DGelsoftware PMID:21904427

  7. Kinetic resolution of racemic mixtures in gel media

    Petrova, Rositza Iordanova

    The goal of this research was to investigate the effect of chiral gels on the chiral crystal nucleation and growth and assess the gels' potential as media for kinetic separation of racemic mixtures. The morphologies of asparagine monohydrate and sodium bromate crystals grown in different gel media were examined in order to discern the effect of gel structure and density on the relative growth rates of those materials. Different crystal habits were observed when the gel chemical composition, density and solute concentration were varied. These studies showed that the physical properties of the gel, such as gel density and pore size, as well as its chemical composition affect the crystal habit. The method of kinetic resolution in gel media was first applied to sodium chlorate, which is achiral in solution but crystallizes in a chiral space group. Crystallization in agarose gels yielded an enantiomorphic bias, the direction and magnitude of which could be affected by changing the temperature or by the addition of an achiral cosolvent. Aqueous gels at 6°C produced crystalline mixtures enriched with the d-enantiomorph, while crystallization under MeOH diffusion favored l-crystals. Optimized conditions yielded e.e. of 53% of l-enantiomorph. The method was next applied to the organic molecular crystals of asparagine monohydrate and threonine. Asparagine monohydrate growth in aqueous agarose and iota-carrageenan gels produced crystal mixtures enriched with D-enantiomer. The degree of resolution was higher when the total amount of asparagine crystallized was low. The success of the resolution depends strongly on the concentrations of solute and the geling substance. Growth from agarose gels yielded e.e. of 44% under optimized conditions. The same method was applied to the resolution of Thr, albeit with modest success. In an effort to improve the resolution of asparagine monohydrate, agarose was synthetically modified by esterifying its side chains with homochiral asparagyl

  8. Strippable gel for decontamination of contaminated metallic surfaces

    Periodic decontamination of radioactive laboratories including fume hoods, glove boxes and all surfaces used for handling, processing and transporting radioactive materials is mandatory in all nuclear installations as this reduces spread of contamination and decreases total man rem exposure. Conventionally, chemical decontaminating agents or surfactant solutions are used for this purpose. However, this approach leads to generation of large volume of secondary radioactive waste. The use of strippable gel is an attractive alternative with low secondary waste generation particularly where removal of loose or weakly fixed contamination is necessary and also when the decontaminated material are to be reused, for e.g. decontamination of fume hoods, glove boxes, transport casks, spent fuel storage racks, control rod drive transport containers etc. Literature on gel formulations is scarce and mostly in the patent form. The sustained effort on gel formulation development has resulted in a basic gel formulation. The gel is a highly viscous water-based organic polymer, particularly suitable for application on vertical surfaces including difficult to reach metallic surfaces of complex geometry and not just limited to horizontal surfaces. The gel can be easily applied on contaminated surfaces by brushing or spraying. Curing of the gel is complete within 16-24 hours under ambient conditions and can then be removed by peeling as a dry sheet. While curing, the contaminants are trapped in gel either physically or chemically depending upon the nature of the contaminant. Salient features of cured gel include that it is water soluble and can be disposed off after immobilization in cement. Decontamination performance of the gel was initially evaluated by applying it on SS planchettes contaminated with known amount of radionuclides such as Cs(I), Co(II) and Ce(III). The measured decontamination factor was found to be in the range of 50-500, lowest for Ce(III) and highest for Co

  9. Development of an injectable chitosan/marine collagen composite gel

    A chitosan/marine-originated collagen composite has been developed. This composite gel was characterized and its biocompatibility, as well as an inflammatory reaction, was observed. The chitosan gel including N-3-carboxypropanoil-6-O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol% and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with the salmon atelocollagen (SA) gel at different mixture ratios. The composite gels were injected subcutaneously in to the back of rats. The specimens were harvested for a histological survey as well as a tumor necrosis factor-alpha (TNF-α) assay by ELISA. The inflammatory cell infiltration and release of TNF-α were successively controlled low with the ratio of SA to chitosan at 10:90 or 20:80. The SA gel first, within 2 weeks, and then chitosan in the composite gel were slowly absorbed after implantation, followed by soft tissue formation. It is expected that this composite gel will be available as a carrier for tissue filler and drug delivery systems.

  10. Development of an injectable chitosan/marine collagen composite gel

    Wang Wei [Department of Inorganic Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062 (Japan); Itoh, Soichiro [Affiliated Facility for Clinical and Fieldwork Practices, International University of Health and Welfare, 6-1-14 Kounodai, Ichikawa-shi, Chiba 272-0827 (Japan); Aizawa, Tomoyasu; Demura, Makoto [Division of Molecular Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810 (Japan); Okawa, Atsushi [Department of Orthopaedic and Spinal Surgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519 (Japan); Sakai, Katsuyoshi; Ohkuma, Tsuneo, E-mail: itoso.gene@kaken-hp.or.j [Research and Development Division, Hokkaido Soda Co., Ltd, 2-12 Chitose, Noboribetsu-shi 059-0003 (Japan)

    2010-12-15

    A chitosan/marine-originated collagen composite has been developed. This composite gel was characterized and its biocompatibility, as well as an inflammatory reaction, was observed. The chitosan gel including N-3-carboxypropanoil-6-O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol% and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with the salmon atelocollagen (SA) gel at different mixture ratios. The composite gels were injected subcutaneously in to the back of rats. The specimens were harvested for a histological survey as well as a tumor necrosis factor-alpha (TNF-{alpha}) assay by ELISA. The inflammatory cell infiltration and release of TNF-{alpha} were successively controlled low with the ratio of SA to chitosan at 10:90 or 20:80. The SA gel first, within 2 weeks, and then chitosan in the composite gel were slowly absorbed after implantation, followed by soft tissue formation. It is expected that this composite gel will be available as a carrier for tissue filler and drug delivery systems.

  11. Western Blot of Stained Proteins from Dried Polyacrylamide Gels

    Gruber, Claudia; Stan-Lotter, Helga

    1996-01-01

    Western blotting of proteins is customarily performed following their separation on polyacrylamide gels, either prior to staining (1) or, as recently reported, following staining (2). We describe here Western blotting with stained gels, which had been dried and some of which had been stored for years. This procedure permits immunological analysis of proteins, to which antisera may have become available only later, or where the application of newly developed sensitive detection methods is desired. Once rehydration of the gels is achieved, proteins can be-transferred to blotting membranes by any appropriate protocol. Proteins stained with Coomassie Blue have to be detected with a non-chromogenic method, such as the film-based enhanced chemiluminescence (ECL)2) procedure (3). Silver stained proteins, which transfer in the colorless form, may be visualized by any detection method, although, because of the usually very low amounts of proteins, detection by ECL is preferable. Blotting of stained proteins from rehydrated gels is as rapid and as quantitative as from freshly prepared gels, in contrast to blotting from wet stained gels, which requires extensive washing and results in low transfer efficiency (2). Together with a photographic record of the gel pattern, unambiguous identification of immunoreactive proteins from complex mixtures is possible. Some further applications of this work are discussed.

  12. Rubber-like poly(vinyl alcohol) gel

    Anomalous poly (vinyl alcohol) gel has been found in our laboratory since 1980. The gel is prepared by repeated freezing (or freeze-dehydration) of aqueous poly (vinyl alcohol). Experiments establish the fact that anomalous gel is never produced in the course of freezing, but during sustained thawing the gelation does occur. Moreover, it was found that the softening point of the gel increases at 37degC. It is assumed that crystal nuclei are generated on freezing, then on thawing, some of them grow to very fine crystals which act as polymer network-knots (cross-linking). Additional freezing provide other seeds, which grow similarly, and these are accumulated until rubber-like gel is produced. The gel was always water-resistant at 37degC, and the potassium permanganate consumption of the extracted water layer remained far below the official restricted value for medical materials. The gel can be sterilized with gamma-rays or chlorhexidine. Moreover, it satisfies the official standards of acute toxicity, pyrogen, intracutaneous reaction, hemolyzation, and intracorporeal implantation, respectively. Applications to adhesion-preventing membrane (for joint or pericardium), tamponade (for jaw defects), electrode (for electroretinogram or artificial inner ear), artificial denture base and phantoms for magnetic resonance imaging were examined. (author) 54 refs

  13. Rubber-like poly(vinyl alcohol) gel

    Nambu, Masao (Nippon Oil Co. Ltd., Yokohama (Japan). Central Technical Research Lab.)

    1990-09-01

    Anomalous poly (vinyl alcohol) gel has been found in our laboratory since 1980. The gel is prepared by repeated freezing (or freeze-dehydration) of aqueous poly (vinyl alcohol). Experiments establish the fact that anomalous gel is never produced in the course of freezing, but during sustained thawing the gelation does occur. Moreover, it was found that the softening point of the gel increases at 37degC. It is assumed that crystal nuclei are generated on freezing, then on thawing, some of them grow to very fine crystals which act as polymer network-knots (cross-linking). Additional freezing provide other seeds, which grow similarly, and these are accumulated until rubber-like gel is produced. The gel was always water-resistant at 37degC, and the potassium permanganate consumption of the extracted water layer remained far below the official restricted value for medical materials. The gel can be sterilized with gamma-rays or chlorhexidine. Moreover, it satisfies the official standards of acute toxicity, pyrogen, intracutaneous reaction, hemolyzation, and intracorporeal implantation, respectively. Applications to adhesion-preventing membrane (for joint or pericardium), tamponade (for jaw defects), electrode (for electroretinogram or artificial inner ear), artificial denture base and phantoms for magnetic resonance imaging were examined. (author) 54 refs.

  14. Development of strippable gel for surface decontamination applications

    Strippable gels are an attractive option for decontamination of surfaces particularly when materials are to be reused after decontamination. The process in general results in good decontamination performance with minimal secondary waste generation. This paper reports on development of strippable gel formulation using polyvinyl alcohol as the gel former. Peeling behavior of the gel film improved when glycerol was used as plasticizer. Incorporation of decontaminating agents is essential for the gel to be effective, so a number of decontaminating agents were screened based on their miscibility with the gel, smooth peeling, and good decontamination performance. Based on this study, a strippable gel, ‘INDIGEL’ was formulated as a potential candidate for surface decontamination applications. Extensive trials on evaluation of decontamination performance of Indigel were done on simulated surfaces like stainless steel tray, stainless steel fume hood, PVC floor, granite and ceramic table tops. Results show that Indigel is highly effective for decontamination of surfaces contaminated with all types of radionuclides. Simplicity of its use coupled with good decontamination ability will find application in nuclear and other chemical industries. (author)

  15. Implementation of MRI gel dosimetry in radiation therapy

    Baeck, S.Aa.J

    1998-12-01

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification 103 refs, 20 figs, 6 tabs

  16. Implementation of MRI gel dosimetry in radiation therapy

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification

  17. Thorium inorganic gels and phosphoric complexes

    To get a better understanding of inorganic transparent gels formation in phosphonitric aqueous solutions obtained by mixing a thorium nitrate solution (10-2 to 5 x 10-1 M) with a phosphoric acid solution (1.33 more concentrated) at pH 0.5 to 1, we investigated the complexing of thorium in this medium. As nitrate ions are very weak complexing agents, only phosphate ions have been studied in the thorium phosphate complexes formation. The phosphoric medium have been defined by two independant parameters CTh and pH. The actual H3PO4 concentration at the equilibrium: [H3PO4] determines, with the pH conditions, the thorium complexes formation. Nevertheless, this free phosphoric acid concentration is less than 0.5 M, which corresponds to the upper value that could be reach by [H3PO4] if thorium ions were not complexed at pH 1.5. Thorium complexes have been identified and their equilibrium constant formation have been calculated from extrapolated data obtained at tracers scale with a radioactive thorium isotope: Th-227. These data have been obtained in phosphoric medium defined by [H3PO4]=2 M and 0.7Th and pH values

  18. Casting AISI 316 steel by gel cast

    The feasibility of producing AISI 316 steel components from their powders and avoiding their compaction is analyzed. A casting technique is tested that is similar to gel casting, used for ceramic materials. In the initial stage, the process consists of the formulation of a concentrated barbotine of powdered metal in a solution of water soluble organic monomers, which is cast in a mold and polymerized in situ to form a raw piece in the shape of the cavity. The process can be performed under controlled conditions using barbotines with a high monomer content from the acrylimide family. Then, the molded piece is slowly heated until the polymer is eliminated, and it is sintered at temperatures of 1160oC to 1300oC under a dry hydrogen atmosphere, until the desired densities are attained. The density and micro structure of the materials obtained are compared with those for the materials compacted and synthesized by the conventional processes. The preliminary results show the feasibility of the process for the production of certain kinds of structural components (CW)

  19. Drying and shrinkage of polymer gels

    S. S. Waje

    2005-06-01

    Full Text Available The polymer hydrogel was synthesized by photo-polymerization process (UV light, 60 ºC in presence of Photo-initiator (IrgacureR and Cross-linker (NN'-methylene bisacrylamide; MBAM. In the present work, the drying of polymer hydrogel was carried out to study the effect of temperature, gel-sheet thickness, monomer ratio of acryl acid to acrylamide (AA/AM, concentration of MBAM and quantity of monomers. A correlation has been developed for modified sheet thickness as a function of contraction coefficient and degree of drying. Effective diffusivity was estimated from Fickian-diffusive model considering modified sheet thickness and was found to be in the range of 1.1 ´ 10-10-5.93 ´ 10-10 m²/s. The activation energy obtained using Arrhenius type equation was found to be in the range of 2979-10737 kJ/kmol H2O. The drying behavior shows an initial shoot-up in drying rate followed by constant rate and two falling rate periods.

  20. Porating anion-responsive copolymeric gels.

    England, Dustin; Yan, Feng; Texter, John

    2013-09-24

    A polymerizable ionic liquid surfactant, 1-(11-acryloyloxyundecyl)-3-methylimidiazolium bromide (ILBr), was copolymerized with methyl methacrylate (MMA) in aqueous microemulsions at 30% (ILBr w/w) and various water to MMA ratios. The ternary phase diagram of the ILBr/MMA/water system was constructed at 25 and 60 °C. Homopolymers and copolymers of ILBr and MMA were produced by thermally initiated chain radical microemulsion polymerization at various compositions in bicontinuous and reverse microemulsion subdomains. Microemulsion polymerization reaction products varied from being gel-like to solid, and these materials were analyzed by thermal and scanning electron microscopy methods. Microemulsion polymerized materials were insoluble in all solvents tested, consistent with light cross-linking. Ion exchange between Br(-) and PF6(-) in these copolymeric materials resulted in the formation of open-cell porous structures in some of these materials, as was confirmed by scanning electron microscopy (SEM). Several compositions illustrate the capture of prepolymerization nanoscale structure by thermally initiated polymerization, expanding the domain of compositions exhibiting this feat and yet to be demonstrated in any other system. Regular cylindrical pores in interpenetrating ILBr-co-MMA and PMMA networks are produced by anion exchange in the absence of templates. A percolating cluster/bicontinuous transition is "captured" by SEM after using anion exchange to visualize the mixed cluster/pore morphology. Some design principles for achieving this capture and for obtaining stimuli responsive solvogels are articulated, and the importance of producing solvogels in capturing the nanoscale is highlighted. PMID:23968242

  1. PMMA-based Gel Polymer Electrolytes with Crosslinking Network

    H.P. Zhang; Y. P. Wu; H. Q. Wu; M. Sun

    2005-01-01

    @@ 1Introduction The lithium-ion battery has a good rate capability and low-temperature performance, but its safety is relatively low due to the possibility of leakage of liquid electrolyte. The use of a solid or gel type electrolyte can lower the probability of leakage liquid electrolyte, and the electrochemical performance of gel electrolyte doesn't decrease so markedly as the solid electrolyte. Now, new types of advanced lithium-ion battery with gel polymer electrolytes are under developing which can be used in the future.

  2. Critical, elasticity of polyacrylamide above its gel point

    Gauthier-Manuel, B.; Guyon, E.

    1980-01-01

    We study the reticular polymerization of a gel of mono and bisacrylamide around the gelation threshold. A rheological measurement using the Stokes relative displacement of a sphere within the medium gives access to the viscosity below the gel point and to an elastic modulus E above it. From the first determination we deduce the gel time T = Tc (evaluated from the start of the polymerization). A critical variation E(T) ∝ (T - Tc) t is obtained for 2 x 10-3 < (T - T c)/Tc < 10-1 with an exponen...

  3. Strain identification in Rhizobium by starch gel electrophoresis of isoenzymes

    Engvild, Kjeld Christensen; Nielsen, G.

    1985-01-01

    Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol and...... arabinose and other sugars as enzyme inducers. After electrophoresis the gels were separated into several slabs by a gel cutter. Each slab was stained for a particular enzyme. Among numerous enzyme systems tested we found useful variation in esterases (EC 3.1.1.1, EC 3.1.1.2), 3-hydroxybutyrate...

  4. COMPARATIVE STUDIES ON POVIDONE-IODINE OINTMENT AND GEL

    T. Mangilal*, K. S. K. Rao Patnaik , R. Sivakumar , Y. Sudhakar and S. K. Basu

    2012-11-01

    Full Text Available Povidone-Iodine Ointment was prepared using polyethylene glycol base by fusion method and the gel was prepared using Poloxamer 407 as a gelling agent by cold process. The different characteristics of povidone-iodine ointment and gel were compared from the results obtained for assay and total, available and complex iodine contents. These values were comparable with marketed formulations. The formulations were tested for wound healing and antimicrobial activity. Wound healing studies show that the time taken for complete wound healing was slightly less for prepared povidone-iodine ointment and gel than the marketed preparations. Antimicrobial activity also found to be almost equal for the different formulations.

  5. In-phantom dose imaging with polymer gel layer dosimeters

    Vanossi, E. [Department of Energy, Nuclear Engineering Division, Polytechnic of Milan, Via Ponzio 34/3, 20133 Milano (Italy); INFN Milan, Via Celoria 16, 20133 Milano (Italy); Carrara, M. [Fondazione IRCCS ' Istituto Nazionale Tumori' , Via Venezian 1, 20133 Milano (Italy); Gambarini, G. [Department of Physics, University of Milan, Via Celoria 16, 20133 Milano (Italy); INFN Milan, Via Celoria 16, 20133 Milano (Italy)], E-mail: grazia.gambarini@mi.infn.it; Negri, A. [Department of Physics, University of Milan, Via Celoria 16, 20133 Milano (Italy); Mariani, M. [Department of Energy, Nuclear Engineering Division, Polytechnic of Milan, Via Ponzio 34/3, 20133 Milano (Italy)

    2009-07-15

    Gel dosimeters in form of layers have shown noticeable potentiality for in-phantom dose profiling and imaging in BNCT neutron fields. Such dosimeters give the possibility of achieving spatial dose distributions of each dose contribution in neutron fields. The various dose components are separated by means of pixel-to-pixel manipulations of pairs of images acquired with gel dosimeters having different isotopic compositions. The reliability of polymer-gel-layer dosimeters (PGLD) for BNCT has been studied and their utilisation limits have been inspected.

  6. Silica Sol-Gel Entrapment of the Enzyme Chloroperoxidase

    Van Tuan Le; Selina Chan; Bassem Ebaid; Monika Sommerhalter

    2015-01-01

    The enzyme chloroperoxidase (CPO) was immobilized in silica sol-gel beads prepared from tetramethoxysilane. The average pore diameter of the silica host structure (~3 nm) was smaller than the globular CPO diameter (~6 nm) and the enzyme remained entrapped after sol-gel maturation. The catalytic performance of the entrapped enzyme was assessed via the pyrogallol peroxidation reaction. Sol-gel beads loaded with 4 μg CPO per mL sol solution reached 9–12% relative activity compared to free CPO in...

  7. Electron beam sterilization of the agarose gel used for electrophoresis

    The results obtained by electron beam (EB) sterilization of the plates with agarose gel used for human serum protein electrophoresis are presented. Also, the results obtained by human serum protein electrophoresis performed with agarose gel plates irradiated at different EB doses, from 4 kGy to 20 kGy, are presented. The microbiological results demonstrate that above 5 kGy the irradiated agarose plates are sterile. The EB irradiation of the agarose gel plates in the dose range of 7-9 kGy gives the best results for both, sterilization and protein fraction separation processes. (author)

  8. Orientation of the agarose gel matrix in pulsed electric fields.

    Stellwagen, J; Stellwagen, N C

    1989-01-01

    The technique of transient electric birefringence was used to investigate the effect of pulsed electric fields on the orientation of the agarose gel matrix. Orientation of the gel was observed at all electric field strengths. Very slow, time-dependent effects were observed when pulses of 10-100 V/cm were applied to 1% gels for 0.5-2 seconds, indicating that domains of the matrix were being oriented by the electric field. The sign of the birefringence reversed when the direction of the applied...

  9. Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

    Chen M

    2011-11-01

    Full Text Available Meiwan Chen1,2,‡, Zhiwen Yang1,‡, Hongmei Wu1, Xin Pan1, Xiaobao Xie3, Chuanbin Wu11Research and Development Center of Pharmaceutical Engineering, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China; 2State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China; 3Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, China ‡These authors contributed equally to this workPurpose: The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa.Patients and methods: This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria. The cell morphology of normal and treated bacteria cells was assessed by transmission electron microscopy (TEM, and the effects of S-T-Gel on genome DNA of bacterial cells were evaluated by agarose gel electrophoresis.Results: S-T-Gel showed promising activity against Staphylococcus aureus and moderate activity against Escherichia coli and Pseudomonas aeruginosa. The observation with TEM suggested that S-T-Gel may destroy the structure of bacterial cell membranes in order to enter the bacterial cell. S-T-Gel then condensed DNA and combined and coagulated with the cytoplasm of the damaged bacteria, resulting in the leakage of the cytoplasmic component and the eventual death of these three bacteria. In addition, the analysis of agarose gel electrophoresis demonstrated that S-T-Gel could increase the decomposability of genome DNA.Conclusion: These results about promising antimicrobial activity and mechanism of S-T-Gel may be useful for further research

  10. Gel Electrophoresis of Gold-DNA Nano-Conjugates

    Pellegrino, T.; Sperling, R.A.; Alivisatos, A.P.; Parak, W.J.

    2006-01-10

    Single stranded DNA of different lengths and different amounts was attached to colloidal phosphine stabilized Au nanoparticles. The resulting conjugates were investigated in detail by a gel electrophoresis study based on 1200 gels. We demonstrate how these experiments help to understand the binding of DNA to Au particles. In particular we compare specific attachment of DNA via gold-thiol bonds with nonspecific adsorption of DNA. The maximum number of DNA molecules that can be bound per particle was determined. We also compare several methods to used gel electrophoresis for investigating the effective diameter of DNA-Au conjugates, such as using a calibration curve of particles with known diameters and Ferguson plots.

  11. Effect of Electron beam on Prepared HAP-Gel Composition

    Naima A. El Gendy*,Tawfik M. S.**, and Asma M. Nour

    2014-04-01

    Full Text Available Background: Polyvinyl alcohol liquid PVAl was used as the organic carrier for Hydroxylapatite-gel (Hap-gel composite. PVAl has the ability to form a nano- hydroxylapatite polyvinyl alcohol composite gel which has a wide range of uses in different environmental and medical applications. Prepared Hap-gel is known to have a very similar composition to human bone and is used as a substitute for bones in compound fractures and artificial dentures. Matreia and Methods: In this work prepared HAP- gel was exposed to a high ionizing radiation electron beam (5 kilo Gray and an aqueous solution containing aluminum ions (Al+. Some investigations were done to illustrate the effect of radiation exposure and aluminum contamination on prepared Hap-gel. Results: Energy dispersive X-ray analysis (EDx showed that the electron beam used caused an obvious increase in the calcium ions (Ca++ content of the prepared Hap-gel from 60% to 65.69 % with a prominent decrease in phosphorus ions (P + content from 40 % to 34.31 % in addition to an increase in the Ca/P ratio from 1.5 to 1.91. Exposure of the pre-irradiated Hap-gel samples to aluminium ions (Al+ resulted in a noticeable decrease in Ca++ content from 65.69 atomic % to 32.14 % atomic % and a further noticeable decrease in P+ content from 34.31 % atomic % to 13 atomic % as well as an increase in the Ca/P ratio from 1.91 to 2.47. The levels for the original prepared Hap-gel were Ca++; 60 atomic % and P+; 40 atomic %. It was deduced that exposure of the Hap-gel to Al+ had a further damaging effect on the pre-irradiated Hap-gel composition in addition to the damaging effect that the electron beam used induced on the samples. Conclusions: it could be concluded that electron beams and Al+ have an injurious effect on human bone tissue taking into consideration the similarity in composition between Hap-gel and bones. Therefore, this study could be beneficial in the field of osteoporosis research and assist the

  12. Sol-gel technology applied to glass and crystalline ceramics

    Fixation of high level and transuranium radioactive waste in glass or alternative ceramic forms requires remotely operable processes and equipment, and sol-gel technology developed for reactor fuel refabrication appears to be applicable. Advantages of the sol-gel process are absence of dust, easy pneumatic transfer and sampling of either liquids or free-flowing solid microspheres, excellent sinterability, and equipment amenable to remote operation because of mechanical simplicity. Synthetic rock microspheres and pellets containing up to 25% simulated defense waste have been prepared by the sol-gel process. 26 refs

  13. Bi-Sr-Co-O thermoelectrics prepared by sol-gel methods with modified gel decomposition

    Rubešová, K.; Hlásek, T.; Jakeš, V.; Sedmidubský, D.; Hejtmánek, Jiří

    2012-01-01

    Roč. 30, č. 1 (2012), 1-5. ISSN 1757-8981. [Fall Meeting of the European-Materials-Research-Society (E- MRS )/Symposium K - Solution-Derived Electronic-Oxide Films, Nanostructures and Patterning, from Materials to Devices. Warsaw, 19.09.2011-23.09.2011] R&D Projects: GA ČR GA203/09/1036 Institutional research plan: CEZ:AV0Z10100521 Keywords : BiSrCoO * thermoelectrics * sol–gel Subject RIV: BM - Solid Matter Physics ; Magnetism

  14. In situ synthesis of silica gel nanowire/Na+-montmorillonite nanocomposites by the sol-gel route

    Silica-gel nanowire/Na+-montmorillonite (Na+-MMT) nanocomposites were prepared by the in situ sol-gel process of tetraethyl orthosilicate (TEOS) in the presence of Na+-MMT and ammonia as catalyst. Microstructure characterization of the nanocomposites was done by SEM, TEM, EDX, XRD and FTIR. It was found that a lot of silica-gel nanowires grew along the edges of Na+-MMT. The combination between the nanowires and Na+-MMT was accomplished via polycondensation of the hydrolyzed TEOS and the edge -OH groups of Na+-MMT

  15. Preparation and evaluation of soft gellan gum gel containing paracetamol

    Gohel M

    2009-01-01

    Full Text Available The objective of this study was to develop soft paracetamol gel using gellan gum as a gelling agent and sodium citrate as a source of cation. Different batches were prepared using three different concentrations of gellan gum (0.1, 0.3, and 0.5%, each with two different sodium citrate concentrations (0.3 and 0.5%. The consistency of the paracetamol gel was dependent on the concentration of gellan gum, sodium citrate and co-solute. The results of dissolution study of soft gel containing 0.3% gellan gum and 0.3% sodium citrate revealed that paracetamol was completely released in 30 min. Polyethylene glycol 400 worked as a solubilizer for paracetamol. All the gels possessed acceptable sensory characteristics when evaluated by human volunteers. Short term stability study carried out for four weeks at different temperatures revealed no considerable changes in performance characteristics of developed optimized formulation.

  16. Mechanical instability of gels at the phase transition

    Tanaka, Toyoichi; Sun, Shao-Tang; Hirokawa, Yoshitsugu; Katayama, Seiji; Kucera, John; Hirose, Yoshiharu; Amiya, Takayuki

    1987-02-01

    Polymer gels, consisting of a cross-linked polymer network immersed in liquid, undergo a volume phase transition: when external conditions such as temperature or solvent composition change, a gel reversibly swells or shrinks, but does so discontinuously1-5. The volume change at the transition can be as large as a factor of one thousand2, and the phenomenon occurs in all gels6,7. The equilibrium aspects of the phase transition have been extensively studied, but its kinetics have not yet been fully explored. In particular, the appearance of patterns on the originally smooth surface of a gel during the transition makes the kinetic process difficult to understand. Here we elucidate the physical basis underlying the formation and evolution of the pattern.

  17. Investigations of rheological properties of diclofenac sodium gel preparation

    Firuza Maksudova

    2013-04-01

    Full Text Available It is well-known that the majority of non-steroidal anti-inflammatory drugs (NSAIDs are ulcerogenic. Gel or ointment preparations of NSAIDs are free from this side-effect, which is a prerequisite for the increase of aforementioned forms of NSAIDs. A major quality indicator of gels and ointments are rheological properties. Along with determining the quality of preparation, they influence manufacturing, expiration date and terms of storage. This article demonstrates the results of investigation of rheological indices of 3% gel preparation of diclofenac sodium such as plasticity, structural viscosity, and thixotropy. Obtained results confirm that the developed gel preparation has thixotropy, plasticity and is classified as a Bingham system.

  18. Potentiometric estimation of ionic mobilities in PMMA gel electrolytes

    Sedlaříková, M.; Vondrák, Jiří; Reiter, Jakub; Velická, Jana; Jirák, T.

    Banff : USEB, 2007, s. 4. ISBN N. [International Society of Electrochemistry /58./. Banff (CA), 09.09.2007-14.09.2007] Institutional research plan: CEZ:AV0Z40320502 Keywords : gel electrolytes Subject RIV: CA - Inorganic Chemistry

  19. Boroxine ring compounds as dissociation enhancers in gel polyelectrolytes

    In order to combine the advantages of both traditional gel electrolytes and polyelectrolytes, a novel polyelectrolyte which incorporates a boroxine ring-containing anion-trapping agent has been explored. Poly(lithium 2-acrylamido-2-methyl-1-propanesulfonate) (PAMPSLi), ethylene carbonate (EC) and tri(methoxyethoxyethoxyethoxy)boroxine (TME3Bx) were combined to prepare various gel systems. The thermal properties and conductivities of these gels have been investigated. A conductivity of 10-3.6 S cm-1 at 20 deg. C has been achieved in a gel polyelectrolyte system with a molar ratio of [EC]:[TME3Bx]:[Li+]=24:1.7:1. Temperature-dependent NMR measurements indicated that a significant interaction exists between the boroxine ring and the polyelectrolyte

  20. Rheological properties of magneto-responsive copolymer gels

    An, H.

    2012-01-01

    New magneto rheological systems that respond mechanically to external homogeneous magnetic fields, namely, physically cross-linked magneto rheological (MR) gels, were synthesized and investigated. Various aspects of the rheological behavior were considered such as linear viscoelastic response for va

  1. Using Gel Electrophoresis To Illustrate Protein Diversity and Isoelectric Point.

    Browning, Mark; Vanable, Joseph

    2002-01-01

    Demonstrates the differences in protein structures by focusing on isoelectric point with an experiment that is observable under certain pH levels in gel electrophoresis. Explains the electrophoresis procedure and reports results of the experiments. (YDS)

  2. Superabsorbing gel for actinide, lanthanide, and fission product decontamination

    Kaminski, Michael D.; Mertz, Carol J.

    2016-06-07

    The present invention provides an aqueous gel composition for removing actinide ions, lanthanide ions, fission product ions, or a combination thereof from a porous surface contaminated therewith. The composition comprises a polymer mixture comprising a gel forming cross-linked polymer and a linear polymer. The linear polymer is present at a concentration that is less than the concentration of the cross-linked polymer. The polymer mixture is at least about 95% hydrated with an aqueous solution comprising about 0.1 to about 3 percent by weight (wt %) of a multi-dentate organic acid chelating agent, and about 0.02 to about 0.6 molar (M) carbonate salt, to form a gel. When applied to a porous surface contaminated with actinide ions, lanthanide ions, and/or other fission product ions, the aqueous gel absorbs contaminating ions from the surface.

  3. Production of continuous mullite fiber via sol-gel processing

    Tucker, Dennis S.; Sparks, J. Scott; Esker, David C.

    1990-01-01

    The development of a continuous ceramic fiber which could be used in rocket engine and rocket boosters applications was investigated at the Marshall Space Flight Center. Methods of ceramic fiber production such as melt spinning, chemical vapor deposition, and precursor polymeric fiber decomposition are discussed and compared with sol-gel processing. The production of ceramics via the sol-gel method consists of two steps, hydrolysis and polycondensation, to form the preceramic, followed by consolidation into the glass or ceramic structure. The advantages of the sol-gel method include better homogeneity and purity, lower preparation temperature, and the ability to form unique compositions. The disadvantages are the high cost of raw materials, large shrinkage during drying and firing which can lead to cracks, and long processing times. Preparation procedures for aluminosilicate sol-gel and for continuous mullite fibers are described.

  4. Reproducibility study of normoxic polyacrylamide gel (nPAG) dosimeters

    In this study, the overall accuracy of normoxic polyacrylamide gel (nPAG) dosimeters is considered. Different badges of nPAG are fabricated, poured in containers of glass and Barex and irradiated with a 6MV square photon beam. The polymer gel dosimeters were read out using MRI. The overall reproducibility and accuracy of nPAG gel dosimeters was determined by comparison with depth-dose profiles acquired with a Pin Point ionization chamber. Additionally, the effect of the container wall on the depth-dose profile and the effect of temperature changes before and after irradiation on the R2-dose response have been investigated. The average standard deviation and maximum deviation between 8 gel-measured depth-dose profiles and a depth-dose profile measured with an ionization chamber amounted to 0.543 Gy (2.5%) and 2.579 Gy (11.7%) respectively.

  5. IMPROVED SILICA GEL CLEANUP METHOD FOR ORGANOPHOSPHORUS PESTICIDES

    Quantitative recovery of some organophosphorus pesticide residues has not been possible with existing silica gel-cleanup procedures. The authors have developed a modification that permits quantitative recovery of all organophosphorus pesticides tested, except those with a carbama...

  6. Gels correct in-depth reservoir permeability variation

    Smith, J.E.; Mack, J.C. [Tiorco Inc., Denver, CO (United States)

    1997-01-06

    Continuous, long-term injection of an environmentally sound colloidal dispersion gel (CDG) provides a solution to in-depth, away from the well bore, channeling and crossflow problems inherent with waterflooding. This unique in-depth permeability modification process has been applied in 37 field projects over the last 11 years. In the 29 successful projects, the gels increased oil production at lower water/oil ratios. The colloidal dispersion gel was successfully placed at reservoir temperatures up to 202 F. Oil viscosities were often high, from 10 cps to more than 20 cps at the reservoir bottom hole temperature. The paper discusses CDG technology, laboratory work, the gels, field development, initial field results, unsuccessful projects, marginal projects, and successful projects.

  7. SUPER TOUGH GELS WITH A DOUBLE NETWORK STRUCTURE

    Tasuku Nakajima; Takayuki Kurokawa; Hidemitsu Furukawa; Qiu Ming Yu; Yoshimi Tanaka; Yoshihito Osada; Jian Ping Gong

    2009-01-01

    Living tissues work with fantastic functions in soft and wet gel-like state. Thus,hydrogels have attracted much attention as excellent soft and wet materials,suitable for making artificial organs for medical treatments. However,conventional hydrogels are mechanically too weak for practical uses. We have created double network (DN) hydrogels with extremely high mechanical strength in order to overcome this problem. DN gels are interpenetrating network (IPN) hydrogels consisting of rigid polyelectrolyte and soft neutral polymer. Their excellent mechanical properties cannot be explained by the standard fracture theories. In this paper,we discuss about the toughening mechanism of DN gels in accordance with their characteristic behavior,such as large hysteresis and necking phenomenon. We also describe the results on tissue engineering application of DN gels.

  8. Improving gel properties of hairtail surimi by electron irradiation

    Hairtail surimi was subjected to electron irradiation for doses up to 9 kGy. At 7 kGy highest gel strength was achieved. The irradiation also increased lightness and expressible water amount. Scanning electron micrographs showed that 7 kGy irradiation made the surimi protein gel network more compact. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the degradation of myosin heavy chain (MHC) as the irradiation dose increased, particularly at the 7 and 9 kGy doses. Radiation processing may become a new effective tool in surimi production. - Highlights: • The effect of electron irradiation on surimi was investigated. • Gelling properties of surimi gel were improved by 7 kGy electron irradiation. • 7 kGy electron irradiation caused degradation of myosin heavy chain. • Radiation processing can be a new tool for improving surimi products quality

  9. Formulation and in-vitro evaluation of chrysophanol topical gel

    Deepa T Vasudevan

    2011-01-01

    Full Text Available This study describes the formulation and characterization of topical gel of chrysophanol containing carbopol as gel base. The partition of drug between skin and the hydrogel matrix was considered to play an important role in the permeation process. The effect of three levels of carbopol and three different permeation enhancers on chrysophanol permeability was determined in vitro. Each formulation was characterized in terms of viscosity, pH, extrudability, spreadability, homogenicity, drug content, skin irritation, stability, and drug release studies. The gel consisting of 1% carbopol as gel base and 15% dimethylsulfoxide showed superior physicochemical and permeability properties and it was ranked best. Reports of pharmacokinetic parameters showed that the drug release is controlled by both diffusion and relaxation processes.

  10. Studies on supramolecular gel formation using DOSY NMR

    Nonappa, N.; Šaman, David; Kolehmainen, E.

    2015-01-01

    Roč. 53, č. 4 (2015), s. 256-260. ISSN 0749-1581 Institutional support: RVO:61388963 Keywords : DOSY * VT NMR * gel * diffusion coefficients Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.179, year: 2014

  11. Stability of bentonite gels in crystalline rock

    The present, extended study comprises a derivation of a simple rock model as a basis for calculation of the penetration rate of bentonite and of the groundwater flow rate, which is a determinant of the erodibility of the protruding clay film. This model, which is representative of a gross permeability of about 10-8 - 10-9 m/s, implies a spectrum of slot-shaped joints with apertures ranging between 0.1 and 0.5 mm. It is concluded that less than 2percent of the highly compacted bentonite will be lost into traversing joints in 106 years. A closer analysis, in which also Poiseuille retardation and short-term experiments were taken into account, even suggests that the penetration into the considered joints will be less than that. The penetration rate is expected to be 1 decimeter in a few hundred years. The risk of erosion by flowing groundwater was estimated by comparing clay particle bond strength, evaluated from viscometer tests, and theoretically derived drag forces, the conclusion being that the maximum expected water flow rate in the widest joints of the rock model (4 times 10-4 m/s) is not sufficient to disrupt the gel front or the large individual clay flocs that may exist at this front. The experiments support the conclusion that erosion will not be a source of bentonite loss. A worst case scenario with a shear zone being developed across deposition holes is finally considered and in addition to this, the conditions in the fracture-rich tunnel floor at the upper end of the deposition holes are also analysed. This study shows that even if the rock is much more fractured than normal conditions would imply, the bentonite loss is expected to be very moderate and without substantial effect on the barrier functions of the remaining clay cores in the deposition holes. (author)

  12. Self-Healing Corrosion Protective Sol-Gel Coatings

    Abdolah Zadeh, M.

    2016-01-01

    Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic healing approaches. The employed approaches aim at extending the service life of the coating and the underlying substrate by multiple damage closure/sealing and metal surface protection through incorpor...

  13. Chlorhexidine gel associated with papain in pulp tissue dissolution

    Couto De Oliveira, Gabriel; Ferraz, Caio Souza; Andrade Júnior, Carlos Vieira; PITHON, Matheus Melo

    2013-01-01

    Objectives This study aimed to evaluate the capacity of 2% chlorhexidine gel associated with 8% papain gel in comparison with 5.25% sodium hypochlorite in bovine pulp tissue dissolution. Materials and Methods Ninety bovine pulps of standardized sizes were used and fragmented into 5-mm sizes. The fragments were removed from the root middle third region. They were divided into 6 experimental groups (n = 15), 1) 8% papain; 2) 2% chlorhexidine; 3) 2% chlorhexidine associated with 8% papain; 4) 0....

  14. DNA Gel Particles: Particle Preparation and Release Characteristics

    Morán, M. Carmen; Miguel, M. Graça; Lindman, Björn

    2007-01-01

    Aqueous mixtures of oppositely charged polyelectrolytes undergo associative phase separation, resulting in coacervation, gelation, or precipitation. This phenomenon has been exploited here to form DNA gel particles by interfacial diffusion. We report the formation of DNA gel particles by mixing solutions of DNA (either single-stranded (ssDNA) or double-stranded (dsDNA)) with solutions of cationic surfactant CTAB and solutions of the protein lysozyme. Swelling, surface morphology, and DNA rele...

  15. Surfactant−DNA Gel Particles: Formation and Release Characteristics

    Morán, M. Carmen; Miguel, M. Graça; Lindman, Björn

    2007-01-01

    Aqueous mixtures of oppositely charged polyelectrolytes undergo associative phase separation, resulting in coacervation, gelation, or precipitation. This phenomenon has been exploited here to form DNA gel particles by interfacial diffusion. We report on the formation of DNA gel particles by mixing solutions of DNA (either single-stranded (ssDNA) or double-stranded (dsDNA)) with solutions of cationic surfactant cetyltrimetrylammonium bromide (CTAB). By using CTAB, the formation of DNA reservoi...

  16. Facial Gel Complication after Dental Injection: A Case Report

    Pourdanesh, Fereydoun; Shams, Shahin; Sadeghi, Hasan Mir Mohammad

    2013-01-01

    Injectable gel is becoming increasingly popular for cosmetic reasons. The polyacrylamide gel (PAAG) is a permanent filler material used worldwide. In spite of the fact that the filler materials used today are considered quite safe, various complications have been reported in the literature. Hence PAAG use in the United States is not popular. As the area is very close to the dental field, a large complication potential is relatively considered following buccal dental injections. The aim of thi...

  17. Measurement of body fluid proteins by polyacrylamide gel electrophoresis

    Johnson, MH; Thompson, EJ

    1982-01-01

    A development of the disc polyacrylamide gel electrophoretic system of Ornstein and Davis, which has been applied to the analysis of unconcentrated cerebrospinal fluid, is described. Modifications to the scanning densitometer have improved the signal:noise ratio of the gel scanning system. Using this technique, we have studied the dye-binding properties of albumin, and of beta- and gamma-globulins, and have shown that reproducible quantification of proteins can be achieved. The advantages of ...

  18. Visualization of sialoglycoproteins in polyacrylamide gels by acidic ninhydrin reaction.

    Yao,Kenzabroh; Ubuka,Toshihiko; Masuoka,Noriyoshi; Kinuta, Masahiro; Ohta, Jun; Ishino,Kazushi

    1990-01-01

    A new method for staining sialoglycoproteins in polyacrylamide gel after disc electrophoresis is described. The method utilizes the reaction of sialic acids with an acidic ninhydrin reagent which yields a stable color with an absorption maximum at 470 nm. After electrophoresis, the polyacrylamide gel is placed in a test tube and heated with 5 ml of the acidic ninhydrin reagent for 10 min in a boiling water bath. Sialoglycoproteins are detected as brown bands. No additional procedure such as d...

  19. Basics and recent advances of two dimensional- polyacrylamide gel electrophoresis

    Magdeldin, Sameh; Enany, Shymaa; Yoshida, Yutaka; Xu, Bo; Zhang, Ying; Zureena, Zam; Lokamani, Ilambarthi; Yaoita, Eishin; Yamamoto, Tadashi

    2014-01-01

    Gel- based proteomics is one of the most versatile methods for fractionating protein complexes. Among these methods, two dimensional- polyacrylamide gel electrophoresis (2-DE) represents a mainstay orthogonal approach, which is popularly used to simultaneously fractionate, identify, and quantify proteins when coupled with mass spectrometric identification or other immunological tests. Although 2-DE was first introduced more than three decades ago, several challenges and limitations to its uti...

  20. Partition and permeation of dextran in polyacrylamide gel.

    Williams, J C; Mark, L A; Eichholtz, S

    1998-01-01

    Partition of sized FITC-dextrans in polyacrylamide gel showed a relationship between Kav and solute radius as predicted by the theory of Ogston, which is based solely on geometry of the spaces. Permeability data for the same dextrans were fit to several theories, including those based on geometry and those based on hydrodynamic interactions, and the gel structure predicted by the partition and permeability data were compared. The Brinkman effective-medium model (based on hydrodynamic interact...

  1. Simultaneous Immunofluorescent Detection of Coentrapped Cells in Gel Beads

    Prioult, Guenolee; Lacroix, Christophe; Turcotte, Carl; Fliss, Ismaïl

    2000-01-01

    An immunofluorescent method involving double color labeling and confocal microscopy was reported to specifically detect lactic acid bacteria and probiotic cells coimmobilized in gels beads. The method described is rapid (4 h) and sensitive and may be useful for studying cell dynamics during mixed-culture starter production using immobilized cells in gel beads. Microscopic observations were perfectly correlated to cell counts obtained using a sandwich enzyme-linked immunosorbent assay.

  2. Luminescent hybrid porphyrinosilica obtained by sol gel chemistry

    Neri Cláudio Roberto; Calefi Paulo Sergio; Iamamoto Yassuko; Serra Osvaldo Antonio

    2003-01-01

    The sol-gel process is a methodology used to obtain organic-inorganic hybrid solids, which open new possibilities in the field of material science. The sol-gel technique offers a low temperature attractive approach for introducing organic molecules into amorphous materials. In order to introduce tetrakis (2-hydroxy-5-nitrophenyl)porphyrin covalently bounded to a silicate matrix, the inorganic precursor 3-isocyanatopropyltriethoxysilane was added (molar ratio 2:1) to the porphyrin solution in ...

  3. Controlled release gel formulations and preclinical screening of drug candidates

    Ur-Rehman, Tofeeq

    2011-01-01

    Simple gel formulations may be applied to enhance the systemic and local exposure of potential compounds. The aim of this thesis is the development and characterization of controlled release formulations based on thermo-reversible poloxamer gels, which are suitable for novel drug delivery applications.  In particular co-solvents (DMSO, ethanol), mucoadhesive polymers (chitosan, alginate) and salts (sodium tripolyphosphate, CaCl2) have been used to enhance the applications of poloxamer 407 (P4...

  4. Field inversion gel electrophoresis with different pulse time ramps.

    Heller, C.(Fakultät für Physik, Ludwig-Maximilians-Universität München, München, Germany); Pohl, F M

    1990-01-01

    The influence of different pulse time ramps on the separation of yeast chromosomes with field inversion gel electrophoresis (FIGE) was investigated by the means of two dimensional gel electrophoresis. The problem of band inversion, which makes it difficult to distinguish DNA molecules of different size, has been solved by using double randomized pulse times. A major disadvantage of the field inversion technique is thereby overcome, making this system comparable to other pulsed field techniques.

  5. Silver-YBCO composite through citrate gel decomposition

    Silver-YBCO composite containing upto 75% silver has been prepared by thermal decomposition of citrate gel. In this paper the morphological and structural changes taking place during the decomposition of the gel in the range 100--900 degrees C are presented. Heat treatment at 915 degrees C of the composite powder containing Ag2O above a critical limit has been found to impart superconductivity without any external oxygen annealing. The mechanical and microstructural features of the sintered composite are presented

  6. Chemistry of material preparation by the sol-gel process

    Schmidt, Helmut K.

    1988-01-01

    A survey over the role of chemistry in sol-gel processing is given. The basic chemistry of the sol-gel process is complex due to the different reactivities of the network forming and the network modifying components and the wide variety of reaction parameters. Despite the important progress in the investigations of the mechanisms of hydrolysis and condensation, a direct relation of reaction parameters to material properties is still very difficult.

  7. Optical materials by a modified sol-gel nanoparticle process

    Schmidt, Helmut K.; Mennig, Martin

    2000-01-01

    The use of sol-gel derived nanoparticles leads to interesting new materials and systems for optics. The basic principle, to combine transparent matrices with nanoparticles in sizes below remarkable scattering losses opens up new material technologies. The processing is almost as simple as sol-gel processing, and the use of polymerizable nanoparticle even leads to high performance coatings by using simple polymer techniques.

  8. Optical Studies on Sol-Gel Derived Lead Chloride Crystals

    Rejeena, I; Lillibai, B; Nithyaja, B; Nampoori, P.N V; P. Radhakrishnan

    2013-01-01

    Optical characterization of lead chloride crystals prepared by sol-gel method is reported. The relevant sol-gel technique is used for the preparation of PbCl2 samples with five different types. In this paper, we report the absorption and fluorescence behaviour of pure, UV& IR irradiated and electric & magnetic field applied lead chloride crystal samples in solution phase at two different concentrations. Optical bandgap and emission studies of these crystals are also done.

  9. Optical Amplification and Photosensitivity in Sol-Gel Based Waveguides

    Selvarajan, A; T. Srinivas

    2001-01-01

    The sol-gel process has emerged as an effective route for the fabrication of optical waveguides and guided wave devices and circuits. In particular, it is possible to incorporate active dopants like neodymium, erbium, and cesium for integrated optical active devices and circuits. In this paper, a review of recent research on active devices and circuits based on sol-gel process is made. Specific studies undertaken in our laboratory on optical amplification and photosensitivity characteristi...

  10. Sol-gel nanocomposites as functional optical materials

    Schmidt, Helmut K.

    1992-01-01

    Small particle processing opens a variety of interesting aspects for optical applications. For the utilization, the sol-gel process offers a variety of routes, like colloid synthesis, incorporating into sol-gel derived matrices and in combination with photopolyermizabel components patterning processes based on photolithography. In this paper, a summary over a new conception of colloid stabilization and colloid processing by multifunctional ligands and further processing routes for optical app...

  11. Pulsed-field gel electrophoretic analysis of leptospiral DNA.

    Taylor, K A; Barbour, A. G; Thomas, D D

    1991-01-01

    The genomic structures of spirochete species are not well characterized, and genetic studies on these organisms have been hampered by lack of a genetic exchange mechanism in these bacteria. In view of these observations, pulsed-field gel electrophoresis was used to examine the genomes of Leptospira species. Live cells, prepared in agarose plugs, were lysed in situ, and the DNA was analyzed under different electrophoretic conditions. Pulsed-field gel electrophoresis of DNA digested with infreq...

  12. Pulsed field gel electrophoresis on frozen tumour tissue sections.

    Boultwood, J. (Jacqueline); Kaklamanis, L.; Gatter, K. C.; Wainscoat, J S

    1992-01-01

    The application of pulsed field gel electrophoresis (PFGE) to the molecular genetic analysis of solid tumours has been restricted by the requirement for whole single cells as a DNA source. A simple technique which allows for the direct analysis of histologically characterised solid tumour material by pulsed field gel electrophoresis was developed. Single frozen tissue sections obtained from colonic carcinoma specimens were embedded without further manipulation in molten, low melting temperatu...

  13. Further characterization of filarial antigens by SDS polyacrylamide gel electrophoresis

    Dissanayake, S.; Galahitiyawa, S. C.; Ismail, M. M.

    1983-01-01

    SDS (sodium dodecyl sulfate)-polyacrylamide gel electrophoresis of an antigen isolated from sera of Wuchereria bancrofti-infected patients and Setaria digitata antigen SD2-4 is reported. Both antigens showed carbohydrate (glycoprotein) staining. The W. bancrofti antigen had an apparent relative molecular mass of 35 000 while the S. digitata antigen SD2-4 migrated at the marker dye position on SDS-polyacrylamide gel electrophoresis. SDS treatment of these antigens did not abolish the precipita...

  14. Rheological properties of rennet-induced skim milk gels.

    Zoon, P

    1988-01-01

    The rheological properties of rennet-induced skim milk gels, which are viscoelastic materials, were studied under various conditions.Dynamic and stress relaxation experiments were performed at small deformations of the gel network, whereas constant stress (creep) experiments were performed at large deformations. Stress relaxation moduli calculated from the dynamic moduli agreed fairly well with stress relaxation moduli determined by means of stress relaxation experiments, implying that true m...

  15. Strategic analysis for a novel gel electrophoresis technology

    Yu, Jeff

    2007-01-01

    A novel gel electrophoresis technology for separating protein and nucleic acid is under development by a research team at Simon Fraser University (SFU. Compared with the conventional gel electrophoresis technology, the new technology is easier to use, has higher throughput, and lower use cost. The purpose of this project is to help the researchers to commercialize the new technology. This report begins with introduction of the project, followed by an industry analysis. Then it develops and di...

  16. Steady-state leaching of tritiated water from silica gel

    Das, H.A.; Hou, Xiaolin

    2009-01-01

    Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion.......Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion....

  17. Epoxy-silica nanocomposite by nonaqueous sol-gel process

    Ponyrko, Sergii; Matějka, Libor

    Ljubljana : Center for Experimental Mechanics, Faculty of Mechanical Engineering, University of Ljubljana, Institute for Sustainable Innovative Technologies, 2014. s. 55. [International Conference on Modification, Degradation and Stabilization of Polymers /8./ - MoDeSt 2014. 31.08.2014-04.09.2014, Portorož] R&D Projects: GA ČR GAP108/12/1459 Institutional support: RVO:61389013 Keywords : epoxy- silica hybrid * nonaqueous sol- gel process * gel ation Subject RIV: CD - Macromolecular Chemistry

  18. Antifungal activity of aloe vera gel against plant pathogenic fungi

    Aloe vera gel extracted from the Aloe vera leaves was evaluated for their antifungal activity at the rate of 0.15%, 0.25% and 0.35% concentration against five plants pathogenic fungi viz., Aspergillus niger, Aspergillus flavus, Alternaria alternata, Drechslera hawaiensis and Penicillum digitatum 0.35% concentration Aloe vera gel completely inhibited the growth of Drechslera hawaiensis and Alternaria alternata. (author)

  19. Recubrimientos de hidroxiapatita preparados mediante un proceso sol-gel

    Peón, E.; Jiménez Morales, A.; Fernández-Escalante, E.; García-Alonso, M. C.; Escudero, M. L.; J. C. Galván

    2005-01-01

    Hydroxyapatite coatings (HAp) have been obtained starting from precursors of sol-gel type. The coatings previously oxidized were deposited on metal surfaces of a based on iron alloy so-called MA956. The alloys were at high temperatures, in order to improve the adhesion with the hydroxyapatite coatings. The sol-gel coating was obtained applying an aqueous route, using triethyl phosphite and aqueous calcium nitrate, as precursors of phosphorous and calcium, respectively. Different sintering the...

  20. DSC experiments on gel-spun polyethylene fibers

    Hoogsteen, W.; Brinke, G. ten; Pennings, A.J.

    1988-01-01

    The tensile strength of gel-spun polyethylene fibers obtained after hot-drawing depends on spinning conditions such as spinning speed, spinning temperature, spinline stretching, polymer concentration, and molecular weight/molecular weight distribution. High deformation rates in the spinline result in shish-kebab structures which after hot-drawing lead to fibers with poor properties. This is in contrast to hot-drawn fibers obtained from gel-spun fibers with a lamellar structure. Lamellar or sh...

  1. A Biophysical Analysis of the Ocr Protein Gel

    Higham, Richard G

    2007-01-01

    Ocr is unusual among proteins in its ability to form a transparent gel at high ammonium sulphate concentrations. This transition was investigated using a combination of spectroscopic, microscopic and rheological techniques. It occurs sharply at a concentration of 3.2M ammonium sulphate and is not observed with other types of salt. Rheological measurements showed that rather than precipitating under such conditions, ocr forms a weak viscoelastic gel. Far UV circular dichroism sp...

  2. Synthesis of polysaccharide chemical gels by gamma-irradiation

    Recently many biodegradable hydrogel systems have been developed in the area of controlled drug delivery. In previous studies, the authors prepared biodegradable hydrogels by crosslinking natural polymers, such as albumin and dextran, using gamma-irradiation. Natural polymers were functionalized by introducing double bonds through reaction with glycidyl acrylate. The functionalized polymers were then crosslinked to form chemical gels by exposure to gamma-irradiation. In this study, they examined the ability of various polysaccharides to form chemical gels by gamma-irradiation. Dextran, alginic acid, hyaluronic acid, benzyl esters of hyaluronic acid, and gellan were functionalized. The effects of the polymer concentration and the gamma-irradiation dose on the hydrogel formation were examined. All the polysaccharides used formed chemical gels, although the extent of gel formation was different. For alginic acid, hyaluronic acid, and benzyl ester of hyaluronic acid at 25% of esterification degree, the chemical gels were formed at lower polymer concentration and at lower gamma-irradiation dose, if the solution was acidified to pH 3. The ability to form chemical gels with various natural polymers would be useful in the development of controlled drug delivery systems

  3. Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

    Kazuaki Kato

    2015-11-01

    Full Text Available A significantly soft and tough nanocomposite gel was realized by a novel network formed using cyclodextrin-based polyrotaxanes. Covalent bond formation between the cyclic components of polyrotaxanes and the surface of silica nanoparticles (15 nm diameter resulted in an infinite network structure without direct bonds between the main chain polymer and the silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young’s modulus increased with silica content. Gelation did not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for <20% compression strain, indicating an infinite stable network without physical cross-links that have finite lifetime. On the other hand, the infinite network exhibited an abnormally low Young’s modulus, ~1 kPa, which is not explainable by traditional rubber theory. In addition, the composite gels were tough enough to completely maintain the network structure under 80% compression strain. These toughness and softness properties are attributable to both the characteristic sliding of polymer chains through the immobilized cyclodextrins on the silica nanoparticle and the entropic contribution of the cyclic components to the elasticity of the gels.

  4. Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels.

    Kato, Kazuaki; Matsui, Daisuke; Mayumi, Koichi; Ito, Kohzo

    2015-01-01

    A significantly soft and tough nanocomposite gel was realized by a novel network formed using cyclodextrin-based polyrotaxanes. Covalent bond formation between the cyclic components of polyrotaxanes and the surface of silica nanoparticles (15 nm diameter) resulted in an infinite network structure without direct bonds between the main chain polymer and the silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young's modulus increased with silica content. Gelation did not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for <20% compression strain, indicating an infinite stable network without physical cross-links that have finite lifetime. On the other hand, the infinite network exhibited an abnormally low Young's modulus, ~1 kPa, which is not explainable by traditional rubber theory. In addition, the composite gels were tough enough to completely maintain the network structure under 80% compression strain. These toughness and softness properties are attributable to both the characteristic sliding of polymer chains through the immobilized cyclodextrins on the silica nanoparticle and the entropic contribution of the cyclic components to the elasticity of the gels. PMID:26664642

  5. Formation and rupture of Ca2+induced pectin biopolymer gels

    Basak, Rajib; Bandyopadhyay, Ranjini

    When calcium salts are added to an aqueous solution of polysaccharide pectin, ionic cross-links form between pectin chains, giving rise to a gel network in dilute solution. In this work, dynamic light scattering (DLS) is employed to study the microscopic dynamics of the fractal aggregates (flocs) that constitute the gels, while rheological measurements are performed to study the process of gel rupture. As calcium salt concentration is increased, DLS experiments reveal that the polydispersities of the flocs increase simultaneously with the characteristic relaxation times of the gel network. Above a critical salt concentration, the flocs become interlinked to form a reaction-limited fractal gel network. Rheological studies demonstrate that the limits of the linear rheological response and the critical stresses required to rupture these networks both decrease with increase in salt concentration. These features indicate that the ion-mediated pectin gels studied here lie in a `strong link' regime that is characterised by inter-floc links that are stronger than intra-floc links. A scaling analysis of the experimental data presented here demonstrates that the elasticities of the individual fractal flocs exhibit power-law dependences on the added salt concentration. We conclude that when pectin and salt concentrations are both increased, the number of fractal flocs of pectin increases simultaneously with the density of crosslinks, giving rise to very large values of the bulk elastic modulus.

  6. Crystal growth of proteins, nucleic acids, and viruses in gels.

    Lorber, Bernard; Sauter, Claude; Théobald-Dietrich, Anne; Moreno, Abel; Schellenberger, Pascale; Robert, Marie-Claire; Capelle, Bernard; Sanglier, Sarah; Potier, Noëlle; Giegé, Richard

    2009-11-01

    Medium-sized single crystals with perfect habits and no defect producing intense and well-resolved diffraction patterns are the dream of every protein crystallographer. Crystals of biological macromolecules possessing these characteristics can be prepared within a medium in which mass transport is restricted to diffusion. Chemical gels (like polysiloxane) and physical gels (such as agarose) provide such an environment and are therefore suitable for the crystallisation of biological macromolecules. Instructions for the preparation of each type of gel are given to urge crystal growers to apply diffusive media for enhancing crystallographic quality of their crystals. Examples of quality enhancement achieved with silica and agarose gels are given. Results obtained with other substances forming gel-like media (such as lipidic phases and cellulose derivatives) are presented. Finally, the use of gels in combination with capillary tubes for counter-diffusion experiments is discussed. Methods and techniques implemented with proteins can also be applied to nucleic acids and nucleoprotein assemblies such as viruses. PMID:20005247

  7. Nanoparticle gel electrophoresis: bare charged spheres in polyelectrolyte hydrogels.

    Li, Fei; Hill, Reghan J

    2013-03-15

    Nanoparticle gel electrophoresis has recently emerged as an attractive means of separating and characterizing nanoparticles. Consequently, a theory that accounts for electroosmotic flow in the gel, and coupling of the nanoparticle and hydrogel electrostatics and hydrodynamics, is required, particularly for gels in which the mesh size is comparable to or smaller than the particle radii. Here, we present an electrokinetic model for charged, spherical colloidal particles undergoing electrophoresis in charged (polyelectrolyte) hydrogels: the gel-electrophoresis analogue of Henry's theory for electrophoresis in Newtonian electrolytes. We compare numerically exact solutions of the model with several independent asymptotic approximations, identifying regions in the parameter space where these approximations are accurate or break down. As previously assumed in the literature, Henry's formula, modified by the addition of a constant electroosmotic flow mobility, is accurate only for nanoparticles that are small compared to the hydrogel mesh size. We derived an exact analytical solution of the full model by judiciously modifying the theory of Allison et al. for uncharged gels, drawing on the superposition methodology of Doane et al. to account for hydrogel charge. This furnishes accurate and economical mobility predictions for the entire parameter space. The present model suggests that nanoparticle size separations (with diameters ≲40 nm) are optimal at low ionic strength, with a gel mesh size that is selected according to the particle charging mechanism. For weakly charged particles, optimal size separation is achieved when the Brinkman screening length is matched to the mean particle size. PMID:23153681

  8. Non-equilibrium tuning of attractive colloidal gels

    Boromand, Arman; Maia, Joao

    2015-11-01

    In colloidal gel systems, the presence of multiple interactions in multiple length scales such as Van der Waals, depletion attractions, and electrostatic repulsions makes these systems challenging from both experimental and simulation aspects. Recently, there has been growing interest to tune and manipulate the structural and dynamics properties of those systems without adjusting interparticle interactions, just by taking them out of equilibrium. In this work, we used Core-Modified Dissipative Particle Dynamics (CM-DPD) with a modified depletion potential, as a coarse-grain model to address the gel formation process in short ranged-attractive colloidal suspensions for a range of volume fractions and attraction strengths. It is suggested that at high volume fractions and near the glass transition, there is a transformation from non-bonded glass to bonded-glass for which that the effect of topological frustration (caging) will be alleviated by the presence of attractive potentials (bonding) i.e. melting during cooling. In the first part of the presentation, we discuss our similar findings for semi-dilute volume fraction of attractive bimodal colloidal gels at equilibrium, which can be explained through local densification of attractive colloidal gels. In the second part, structural and dynamics properties of arrested gels will be studied under shear and after cessation of shear to study how the different flow profiles and history will alter final morphology of the gel systems.

  9. Theory of volume transition in polyelectrolyte gels with charge regularization

    Hua, Jing; Mitra, Mithun K.; Muthukumar, M.

    2012-04-01

    We present a theory for polyelectrolyte gels that allow the effective charge of the polymer backbone to self-regulate. Using a variational approach, we obtain an expression for the free energy of gels that accounts for the gel elasticity, free energy of mixing, counterion adsorption, local dielectric constant, electrostatic interaction among polymer segments, electrolyte ion correlations, and self-consistent charge regularization on the polymer strands. This free energy is then minimized to predict the behavior of the system as characterized by the gel volume fraction as a function of external variables such as temperature and salt concentration. We present results for the volume transition of polyelectrolyte gels in salt-free solvents, solvents with monovalent salts, and solvents with divalent salts. The results of our theoretical analysis capture the essential features of existing experimental results and also provide predictions for further experimentation. Our analysis highlights the importance of the self-regularization of the effective charge for the volume transition of gels in particular, and for charged polymer systems in general. Our analysis also enables us to identify the dominant free energy contributions for charged polymer networks and provides a framework for further investigation of specific experimental systems.

  10. Experimental study of attenuation properties of normoxic polymer gel dosimeters

    The change in linear attenuation coefficient with absorbed dose has been investigated for aqueous polyacrylamide, gelatine and tetrakis (PAGAT) and aqueous methacrylic acid, gelatine and tetrakis (MAGAT) normoxic polymer gel dosimeters using tetrakis (hydroxy methyl) phosphonium chloride as the antioxidant. The measured linear attenuation coefficient increased linearly with absorbed dose up to 15 Gy for PAGAT gels and 10 Gy for MAGAT gels. Computerized tomography (CT) numbers or Hounsfield units (H) were calculated from the linear attenuation coefficients and compared with values obtained using a CT scanner. Both calculated and measured CT numbers followed a similar pattern when fitted with a biexponential curve. The CT numbers obtained from linear attenuation measurements were found to be greater than that obtained with the CT scanner for both PAGAT and MAGAT polymer gels. The H-dose sensitivities of the MAGAT and PAGAT polymer gel dosimeters measured on a CT scanner were calculated to be (0.85 ± 0.08) H Gy-1 and (0.31 ± 0.03) H Gy-1, respectively. The H-dose sensitivities of the MAGAT and PAGAT polymer gel dosimeters from attenuation measurements were found to be (1.10 ± 0.66) H Gy-1 and (0.34 ± 0.01) H Gy-1, respectively. (note)

  11. Piping and erosion phenomena in soft clay gels

    The present study has confirmed the conclusions from earlier investigations of piping and erosion of soft smectite gels by showing that the erodibility can be predicted by comparing the drag forces exerted by flowing water and the cohesive particle bonds in the gels. Optical microscopy used to identify the detailed erosion mechanisms shows that discrete flakes are not eroded as assumed earlier. The minerals torn off from the gels in fact consist of stable aggregates sized 5-50 μm in the case of electrolyte-poor water and even larger units in ocean-type water. The theoretical model as well as the experiments show that erosion is initiated at a flow rate of 10-4 m/s in the first-mentioned type of water and that it becomes significant at 10-3m/s. In salt water the gels are much more erosion-resistant. Piping, which preceded the erosion in the tests, can take place in the form of radial expansion of natural pore passages in the gels, or by tensile failure, depending on the boundary conditions. Theoretically, the critical pressure to produce piping is about 1 kPa at water content of 1000% of Na montmorillonite and this appeared to be on the same order of magnitude as the experimentally determined values for the very conservative conditions that were applied. Separate tests of a clay rich in hydrous mica showed much less erodibility and higher piping resistance than of the smectite gels. (orig.)

  12. The Influence of Microgravity on Silica Sol-Gel Formation

    Sibille, L.; Smith, D. D.; Cronise, R.; Hunt, A. J.; Wolfe, D. B.; Snow, L. A.; Oldenberg, S.; Halas, N.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    We discuss space-flight experiments involving the growth of silica particles and gels. The effect of microgravity on the growth of silica particles via the sol-gel route is profound. In four different recipes spanning a large range of the parameter space that typically produces silica nanoparticles in unit-gravity, low-density gel structures were instead formed in microgravity. The particles that did form were generally smaller and more polydisperse than those grown on the ground. These observations suggest that microgravity reduces the particle growth rate, allowing unincorporated species to form aggregates and ultimately gel. Hence microgravity favors the formation of more rarefied structures, providing a bias towards diffusion-limited cluster-cluster aggregation. These results further suggest that in unit gravity, fluid flows and sedimentation can significantly perturb sol-gel substructures prior to gelation and these deleterious perturbations may be "frozen" into the resulting microstructure. Hence, sol-gel pores may be expected to be smaller, more uniform, and less rough when formed in microgravity.

  13. Removal properties of dissolved boron by glucomannan gel.

    Oishi, Kyoko; Maehata, Yugo

    2013-04-01

    Boron ions have long been known to form complexes with the cis-diol group of a polysaccharide. Konjac glucomannan (KGM) which is one of polysaccharides was used to remove dissolved boron in this study. KGM forms a complex with boron, but does not remove boron from contaminated waters as well as other polysaccharides because of its high water solubility. Therefore, the removal efficiencies of dissolved boron were examined using both an insoluble KGM gel and KGM semi-gel. The former did not remove dissolved boron, but the latter did. The difference in the ability of boron removal was due to the presence of diol group inside. KGM loses free diol group during the process of gelation. On the other hand, the semi-gel gelated only surface layer in water has diol group inside. The boron removal capacity of the semi-gel was highest at pHs⩾11, when the boron species is present as B(OH)4(-). The capacity was slightly increased by the addition of Al, Ca and Mg under high pH conditions. This was due to co-precipitation of boron with Ca dissolved from the semi-gel. The boron adsorbed to the semi-gel easily was desorbed under low pH conditions and the hysteresis was not found. PMID:23260255

  14. The Synthesis of a Novel Cellulose Physical Gel

    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  15. Dose calibration optimization and error propagation in polymer gel dosimetry

    This study reports on the relative precision, relative error, and dose differences observed when using a new full-image calibration technique in NIPAM-based x-ray CT polymer gel dosimetry. The effects of calibration parameters (e.g. gradient thresholding, dose bin size, calibration fit function, and spatial remeshing) on subsequent errors in calibrated gel images are reported. It is found that gradient thresholding, dose bin size, and fit function all play a primary role in affecting errors in calibrated images. Spatial remeshing induces minimal reductions or increases in errors in calibrated images. This study also reports on a full error propagation throughout the CT gel image pre-processing and calibration procedure thus giving, for the first time, a realistic view of the errors incurred in calibrated CT polymer gel dosimetry. While the work is based on CT polymer gel dosimetry, the formalism is valid for and easily extended to MRI or optical CT dosimetry protocols. Hence, the procedures developed within the work are generally applicable to calibration of polymer gel dosimeters. (paper)

  16. Fabrication and Optimization of a PAGATA gel dosimeter: increasing the melting point of the PAGAT gel dosimeter with agarose additive

    The PAGAT polymer gel dosimeter melts at 30degreeC and even at room temperature during the summer, so it needs to be kept in a cool place such as a refrigerator. To increase the stability of the PAGAT gel, different amounts of agarose were added to the PAGAT gel composition and the PAGATA gel was manufactured. Material and Methods: The PAGATA gel vials were irradiated using a CO-60 machine. Then, the samples were evaluated using a 1.5 T Siemens MRI scanner. The ingredients of the PAGATA normoxic gel dosimeter were 4.5% N-N' methylen-bis-acrylamide, 4.5% acrylamide, 4.5% gelatine, 5 m M tetrakis (THPC), 0.01 mM hydroquinone, 0.5% agarose and 86% de-ionized water (HPLC). Results: Melting point and sensitivity of the PAGAT gel dosimeter with addition of 0.0, 0.3, 0.5, 1.0, 1.5 and 2.0% of agarose were measured, in which the melting points Were increased to 30, 82, 86, 88, 89 and 90degreeC and their sensitivities found to be 0.113, 0.1059, 0.125, 0.122, 0.115 and 0.2 S-1Gy-1 respectively. Discussion and Conclusions: Adding agarose increased the sensitivity and background R2 of the evaluated samples. The optimum amount of agarose was found to be 0.5% regarding these parameters and also the melting point of the gel dosimeter. A value of 0.5% agarose was found to be an optimum value considering the increase of sensitivity to 0.125 and melting point to 86degreeC but at the expense of increasing the background R2 to 4.530.

  17. Simple, Sensitive Zymogram Technique for Detection of Xylanase Activity in Polyacrylamide Gels

    Royer, John C.; Nakas, J. P.

    1990-01-01

    A method capable of detecting as little as 0.11 U of xylanase activity in polyacrylamide gels was developed. The method entails incubation of protein gels in contact with substrate gels containing unmodified xylan, followed by immersion of substrate gels in 95% ethanol. Resulting zymograms contain transparent bands corresponding to enzymatic activity against an opaque background.

  18. Polyacrylamide gel plugs enabling 2-D microfluidic protein separations via isoelectric focusing and multiplexed sodium dodecyl sulfate gel electrophoresis.

    Liu, Jikun; Yang, Shuang; Lee, Cheng S; DeVoe, Don L

    2008-06-01

    In situ photopolymerized polyacrylamide (PAAm) gel plugs are used as hydrodynamic flow control elements in a multidimensional microfluidic system combining IEF and parallel SDS gel electrophoresis for protein separations. The PAAm gel plugs offer a simple method to reduce undesirable bulk flow and limit reagent/sample crosstalk without placing unwanted constraints on the selection of separation media, and without hindering electrokinetic ion migration in the complex microchannel network. In addition to improving separation reproducibility, the discrete gel plugs integrated into critical regions of the chip enable the use of a simple pressure-driven sample injection method which avoids electrokinetic injection bias. The gel plugs also serve to greatly simplify operation of the spatially multiplexed system by eliminating the need for complex external fluidic interfaces. Using an FITC-labeled Escherichia coli cell lysate as a model system, the use of gel plugs is shown to significantly enhance separation reproducibility in a chip containing five parallel CGE channels, with an average variance in peak elution time of only 4.1%. PMID:18449857

  19. Dynamic Behavior and Mass Transport in Polyacrylic Acid Gel by Dynamic Light Scattering

    2002-01-01

    Dynamic behaviors on polyacrylic acid (PAA) gels and mass (small molecules) transports in the gels have been studied mainly by dynamic light scattering (DLS). The cross-linking degree (fc), monomer concentration (Cm) and temperature of the gels have significant influences on its dynamic behavior and mass transport in the gels. The increase of fc leads to decrease of the mesh sizes of the gels, thus the obstacle of the gels for mass transport is increased. As a result, small molecular diffusion Dk in the gels is decreased. So even if for small molecules, the Dk also is influenced.

  20. Energy dependence of radiochromic gels for low-energy photon radiation

    The contribution summarizes the results of measurement of energy dependence of two types of radiochromic gel dosimeters on low energy photon radiation between 14 and 145 keV. The energy dependence was determined for two different types of gels - a well-known Fricke infused xylenol orange ion indicator gel (FX gel) and a gel based on Turnbull blue dye (TB gel). Gel samples in PMMA cuvettes with a front wall replaced by a thin Mylar foil were irradiated at reference photon fields at the Czech Metrology Institute. Response of the irradiated gels was evaluated by UV-VIS spectrophotometry and by photographing with a 16-bit grayscale astronomical CCD camera. It was found out that the response of the TB gel is independent on photon energy down to at least 14 keV photons, while the FX gel is energy dependent for photons below roughly 50 keV (authors)

  1. Slow Release of Plant Volatiles Using Sol-Gel Dispensers.

    Bian, L; Sun, X L; Cai, X M; Chen, Z M

    2014-12-01

    The black citrus aphid, also known as the tea aphid, (Toxoptera aurantii Boyer) attacks economically important crops, including tea (Camellia sinensis (L.) O. Kuntze). In the current study, silica sol-gel formulations were screened to find one that could carry and release C. sinensis plant volatiles to lure black citrus aphids in a greenhouse. The common plant volatile trans-2-hexen-1-al was used as a model molecule to screen for suitable sol-gel formulations. A zNose (Electronic Sensor Technology, Newbury Park, CA) transportable gas chromatograph was used to continuously monitor the volatile emissions. A sol-gel formulation containing tetramethyl orthosilicate and methyltrimethoxysilane in an 8:2 (vol:vol) ratio was selected to develop a slow-release dispenser. The half-life of trans-2-hexen-1-al in the sol-gel dispenser increased slightly with the volume of this compound in the dispenser. Ten different volatiles were tested in the sol-gel dispenser. Alcohols of 6-10 carbons had the longest half-lives (3.01-3.77 d), while esters of 6-12 carbons had the shortest (1.53-2.28 d). Release of these volatiles from the dispensers could not be detected by the zNose after 16 d (cis-3-hexenyl acetate) to 26 d (3,7-dimethylocta-1,6-dien-3-ol). In greenhouse experiments, trans-2-hexen-1-al and cis-3-hexen-1-ol released from the sol-gel dispensers attracted aphids for ≍17 d, and release of these volatiles could not be detected by the zNose after ≍24 d. The sol-gel dispensers performed adequately for the slow release of plant volatiles to trap aphids in the greenhouse. PMID:26470065

  2. Ion-exchange chromatography by dicarboxyl cellulose gel.

    Kim, U J; Kuga, S

    2001-06-01

    A new column packing material for ion-exchange chromatography was prepared from cellulose gel by periodate oxidation followed by chlorite oxidation to form spatially paired carboxyl groups (dicarboxyl cellulose, DCC). The carboxyl group was quantitatively introduced to spherical cellulose gel by controlling the extent of oxidation. The DCC gels were examined for their ion-exchange activity for various amines at pH of 2.5-5.5. In this pH range, aromatic amines with acid dissociation constant (pKa) below 2.7 showed no interaction with DCC gels as expected from their lack of protonation. The amines with pKa greater than 3.3, both aromatic and aliphatic, showed strong interaction corresponding to the amount of carboxyl introduced to the gel. However, these amines showed anomalous dependence on pH of the mobile phase, showing a maximum in retention factor at around pH 4. This is in contrast with the nearly constant retention factor of these amines on conventional carboxylated cellulose packing at pH greater than 4.0. The maximum retention factor at pH 4 of DCC gel was 4-5-times greater than that of conventional gel having a similar amount of carboxyls. Since pKa of dicarboxyl groups ranges 3-5 as determined by acid-base titration, the pH giving maximum retention corresponds to the pH at which one of paired carboxyls is dissociated. Possible cause of this anomaly is presented in terms of dissociation state of dicarboxyl groups and its interaction with amines. PMID:11459309

  3. Salt effect on volume phase transition of a gel.

    Annaka, Masahiko; Amo, Yuko; Sasaki, Shigeo; Tominaga, Yasunori; Motokawa, Keiko; Nakahira, Takayuki

    2002-03-01

    The salt effect on the phase transition of N-isopropylacrylamide (NIPA) gel was studied for alkali-metal chlorides (NaCl, KCl, and CsCl). Low-frequency Raman scattering experiment was conducted to know the dynamic state of water molecule under the presence of salt and its correlation to macroscopic phase behavior of the gel was investigated together with the thermodynamic activities of water molecule of aqueous alkali-metal chloride solutions. The series of swelling experiment reveal that the change in the gel volume phase transition strongly depends on the salt concentration and is related to the dehydration with respect to hydrophobic hydration. From the analysis of the reduced low-frequency Raman spectra in water and aqueous alkali-metal chlorides solutions by the use of the relaxation mode that takes into account the inertia and the non-white effects, the characteristic values of aqueous salt solutions (i.e., relaxation time and modulation speed) indicate that the addition of alkali-metal chloride to gel fluid affects the disruption of water molecules in the hydration shell around the NIPA gel and the formation of the hydrogen-bonded network structure of water around themselves, as a result of which the gel collapses. The chemical potential and the dynamic nature of water molecule at the transition points are well correlated: the chemical potentials at the transition points are almost constant whereas the structure of bulk water is changed by addition of alkali-metal chlorides or change in temperature. These results strongly suggest that the swelling ratio of N-isopropylacrylamide gel is a function of hydration degree, which is regulated by the chemical potential of water. PMID:11909100

  4. Antibacterial Activity of Copaiba Oil Gel on Dental Biofilm

    Simões, Cláudia A.C.G.; Conde, Nikeila C. de Oliveira; Venâncio, Gisely N.; Milério, Patrícia S.L.L.; Bandeira, Maria F.C.L.; da Veiga Júnior, Valdir F.

    2016-01-01

    Amazonian biodiversity products that have been used for years in folk medicine, have emerged as feasible and promising alternatives for the inhibition of microorganisms in dental biofilm. Copaiba oil, a phytotherapic agent widely used by the Amazonian populations, is known for its antibacterial, anti-inflammatory, anesthetic, healing and antitumor medicinal properties. Objective: The aim of this study was to evaluate the in vitro antibacterial activity of copaiba oil (Copaifera multijuga) gel against strains of Streptococcus sp present in dental biofilm. Materials and Methods: The copaiba oil was obtained and the chemical components were identified. The oil emulsions were formulated and used with the Brain Heart Infusion agar diffusion method with strains of Streptococcus mitis, Streptococcus constellatus and Streptococcus salivarius isolated from patients as well as standard strains of S. mitis (ATCC903), S. mutans (ATCC10449), S. sanguinis (ATCC15300) and S. oralis (ATCC10557). The study groups were as follows: experimental copaiba oil gel, 1% chlorhexidine gel (positive control) and base gel (negative control). The seeded plates were incubated at 37ºC for 12, 24 and 48 hours, respectively. The results obtained were analyzed by Shapiro-Wilk and Friedman Tests (p<0.05) for non parametric data and the Tukey test was used for pH values with 5% level of significance. Results: The experimental copaiba oil gel and 1% chlorhexidine gel showed antibacterial activity against the tested microorganisms. Conclusion: The copaiba oil gel demonstrated antibacterial activity against all the strains of Streptococcus sp tested, suggesting that it can be used for dental biofilm control. PMID:27386004

  5. Osteoconducting bioglass synthesis via sol-gel process; Biovidro osteocondutor sintetizado pelo processo sol-gel

    Pereira, R.V.; Aragones, A.; Barra, G.O.M.; Salmoria, G.V.; Fredel, M.C., E-mail: rafaelavpereira@gmail.com [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-07-01

    The presence of bioglasses in scaffolds has been studied as they promote the osteoconduction in bones. The scaffolds are developed in order to induce the repair and regeneration in bone tissue. An absorbable bioglass from SiO2-CaO-P2O5 system was synthesized by sol-gel process with the intent of producing these scaffolds. Bioglass 58S was define for these work once it presents ions (Ca and P) which assist at the carbonated apatite layer formation when released. The apatite layer presents an important role at the bone regeneration and metabolism, being involved at grow and mineralization of bones. FTIR was realized to characterize the synthesized bioglass on its chemical composition, XRD to analyze the crystalline structure, solubility test to observe the weight variance and SEM to observe the particles morphology. The obtained results confirmed the production of a bioglass with the desired composition to produce osteoconducting scaffolds. (author)

  6. Dynamical transition of heat transport in a physical gel near the sol-gel transition

    Kobayashi, Kazuya U.; Oikawa, Noriko; Kurita, Rei

    2015-12-01

    We experimentally study heat transport in a gelatin solution near a reversible sol-gel transition point where viscosity strongly depends on temperature. We visualize the temperature field and velocity field using thermochromic liquid crystals and polystyrene latex particles, respectively. During the initial stages of heating, we find that heat transport undergoes a dynamical transition from conductive to convective. Subsequently, during later stages, we observe that the transport dynamics are much more complex than conventional thermal convections. At the sample’s surface we observe the formation of stagnant domains, which lack fluid flow. Their formation is not due to the effects of local cooling. We determine that it is the dynamics of these stagnant domains that induce convective-conductive-convective transitions.

  7. Gel Generator Technology Viability for Small Scale Production - Indian Experience [Country report: India - GEL Gen.

    The radioisotope 99mTc is used in nearly 80% of all diagnostic imaging procedures in nuclear medicine and hence ensuring its uninterrupted availability is of prime importance to the nuclear medicine industry. Of the various options available for accessing 99mTc from its precursor 99Mo through a generator system, the 99mTc generator using a bed of acidic alumina column for column chromatographic separation of 99mTc from 99Mo remains the most popular procedure world over. The uninterrupted availability of high specific activity (n,f)99Mo, an essential requirement for the alumina column generators and produced by few large scale commercial suppliers, needs to be ensured to avoid frequent disruption in 99mTc supplies. Alternate technologies that could use (n,γ)99Mo to meet partial/complete domestic demands are worth exploring to reduce import dependency/foster self-sufficiency particularly in countries having the necessary infrastructure in place. The Indian pursuit of gel generator technology for 99mTc was driven mainly by three considerations, namely, (i) reliable, well-established and ease of production of (n,γ)99Mo in TBq quantities in the research reactors in Trombay/Mumbai, India, (ii) need for relatively low-cost alternate technology to replace the solvent (MEK) extraction generator system in use in India since 1970s and (iii) minimize dependency on weekly import of fission-produced 99Mo raw material required for alumina column generator. The development of column type 99mTc generator based on conversion of (n,γ)99Mo as zirconium molybdate-99Mo (ZrM) gel matrix and subsequent separation of 99mTc by elution in normal saline was an important development in this direction, as this combines the advantages of using (n,γ)99Mo and a column based separation technique. A considerable volume of work was carried out at the Board of Radiation and Isotope Technology (BRIT) both independently and as a part of IAEA’s CRP [4,9] for standardization of the process. After

  8. Structural development and mechanical response of thermoreversible triblock copolymer gels and gel/nanotube composites

    Schoch, Andrew B.

    Intensive research on block copolymers for their unique phase behavior and natural application as surfactants has gone on for a number of years now. The introduction of these materials into selective solvents has expanded the range of their application to diverse areas, from biological scaffolds and drug delivery to ceramics processing and nanocomposites. This dissertation focuses on a system of AB diblock copolymers and ABA triblock copolymers in the same B selective solvent. In fact, the solvent is only selective for the B blocks at low temperatures. At high temperatures both blocks are readily soluble and the polymers are quite mobile in solution, though upon cooling the copolymers form spherical micelles with the A blocks in the micelle core and B blocks in the micelle corona. The main difference between the diblock and triblock copolymer solutions is that in the triblock copolymer solutions the B midblocks have the ability to form bridges between micelles, ultimately forming a connected network of micelles. The formation of this connected network or gel occurs very quickly over a narrow temperature range and is reversible. It transforms the solution at elevated temperatures from a concentrated polymer solution that exhibits very little elasticity to a soft gel which is mostly elastic in its mechanical response. The fast transition, low elasticity at elevated temperatures, and surfactant nature of the block copolymers all make this a model system for the study of carbon nanotubes as fillers in polymers. Carbon nanotubes have been shown to exhibit unique mechanical, electrical, thermal, and optical properties which make them a potentially interesting filler material in polymer composites. The mechanical properties of both these nanocomposites and the nascent copolymer solutions have been studied extensively in this text. This research was motivated by a desire to understand structural development on a fundamental level for both the networks of block copolymers

  9. Effect of drying methods on retention of moist sucralfate gel properties

    Maggi, L; Catellani, P. L.; Fisicaro, E; Santi, P.; Zani, F; Massimo, G.; Colombo, P.

    2000-01-01

    The aim of this work was to find a drying procedure for moist sucralfate gel capable of producing dried sucralfate gel that retains the original gel properties of bioadhesion, rheology, and micromeritics. Spray-drying and microwave-drying procedures were employed. Mannitol was used as a gel-protective substance during the drying processes. The spray drying of moist sucralfate gel gave rise to a powder whose water suspensions showed significantly reduced viscosity. The bioadhesion of spray-dri...

  10. Purification of Peptide Components including Melittin from Bee Venom using gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis

    Young Chon Choi; Ki Rok, Kwon; Suk Ho, Choi

    2006-01-01

    Objectives : This study was conducted to carry out Purification of Melittin and other peptide components from Bee Venom using gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis Methods : Melittin and other peptide components were separated from bee venom by using gel filtration chromatography on Sephadex G-50 column in 0.05M ammonium acetate buffer. Results : Melittin and other peptide components were separated from bee venom by using gel filtration...

  11. P164-M Optimization of the Gel Shredder: A Centrifugal Device for Automated In-gel Digestion with Improved Peptide Recovery.

    Lazarev, A.; Rejtar, T.; Karger, B. L.

    2007-01-01

    Proteomic workflow frequently involves gel separations. Poor peptide recovery from in-gel digestion procedures is at large influenced by the properties of polyacrylamide gel, which restricts access of proteolytic enzymes to the protein substrate as well as prevents complete extraction of certain peptides. We have designed an optimized centrifugal device which allows integrated washing, destaining and shredding of gel bands into uniform blocks of controlled size, roughly 100 μm, prior to the e...

  12. Gels from soft hairy nanoparticles in polymeric matrices

    Vlassopoulos, Dimitris

    2013-03-01

    Hairy particles represent a huge class of soft colloids with tunable interactions and properties. Advances in synthetic chemistry have enabled obtaining well-characterized such systems for specific needs. In this talk we present two model hairy soft particles with diameters of the order of tens of nanometers, star polymers and polymerically grafted spherical particles. In particular, we discuss design strategies for dispersing them in polymeric matrices and eventually creating and breaking gels. Control parameters are the matrix molar mass, the grafting density (or functionality) and the size of the grafts (or arms). The linear viscoelastic properties and slow time evolution of the gels are examined in view of the existing knowledge from colloidal gels consisting of micron-sized particles, and compared. In the case of stars we start from a concentrated glassy suspension in molecular solvent and add homopolymer at increasing concentration, and as a result of the induced osmotic pressure the stars shrink and a depletion gel is formed. For the grafted colloidal particles, they are added at low concentration to a polymer matrix, and it has been shown that under certain conditions the anisotropy of interactions gives rise to network formation. We then focus on the nonlinear rheological response and in particular the effect of shear flow in inducing a solid to liquid transition. Our studies show that the yielding process is gradual and shares many common features with that of flocculated colloidal suspensions, irrespectively of the shape of the building block of the gel. Whereas shear can melt such a gel, it cannot break it into its constituent blocks and hence fully disperse the hairy nanoparticles. On the other hand, the hairy particles are intrinsically hybrid. We show how this important feature is reflected on the heating of the gels. In that case, the mismatch of thermal expansion coefficients of core and shell appears to play a role on the particle response as it

  13. Nanoparticles laden in situ gel for sustained ocular drug delivery

    Himanshu Gupta

    2013-01-01

    Full Text Available Proper availability of drug on to corneal surface is a challenging task. However, due to ocular physiological barriers, conventional eye drops display poor ocular bioavailability of drugs (< 1%. To improve precorneal residence time and ocular penetration, earlier our group developed and evaluated in situ gel and nanoparticles for ocular delivery. In interest to evaluate the combined effect of in situ gel and nanoparticles on ocular retention, we combined them. We are the first to term this combination as "nanoparticle laden in situ gel", that is, poly lactic co glycolic acid nanoparticle incorporated in chitosan in situ gel for sparfloxacin ophthalmic delivery. The formulation was tested for various physicochemical properties. It showed gelation pH near pH 7.2. The observation of acquired gamma camera images showed good retention over the entire precorneal area for sparfloxacin nanoparticle laden in situ gel (SNG as compared to marketed formulation. SNG formulation cleared at a very slow rate and remained at corneal surface for longer duration as no radioactivity was observed in systemic circulation. The developed formulation was found to be better in combination and can go up to the clinical evaluation and application.

  14. Uptake and Recovery of Lead by Agarose Gel Polymers

    Anurag Pandey

    2009-01-01

    Full Text Available Problem statement: The uptake and recovery of lead ions were investigated by using agarose gel polymers. Approach: The experimental results showed that the agarose gel were effective in removing Pb (II from solution. Biosorption equilibrium was approached within 4 h. Pseudo second-order was applicable to all the sorption data over the entire time range. Results: The sorption data conformed well to both the Langmuir and the Freundlich isotherm model. The maximum adsorption capacity (qmax onto agarose gel was 115 mg g-1 for Pb (II. The maximum uptake of metal ions was obtained at pH 2.0. At temperature 35°C, the biosorption of metal ions was found to be highest, with increase or decrease in temperature resulted in a decrease in the metal ions uptake capacity. Conclusion: Elution experiments were carried out to remove Pb (II ions from loaded agarose gel and the bound metal ions could be eluted successfully using 0.1 M EDTA solution. The results suggest that agarose gel can be used as a biosorbent for an efficient removal of Pb(II ions from aqueous solution.

  15. Formulation and Evaluation of Ethosomal Topical Gels of Etoricoxib

    S. Indira

    2015-11-01

    Full Text Available The aim of the current investigation was to develop an Etoricoxib loaded ethosomal gel for better anti-inflammatory activity by sustaining the drug release and reduces adverse effects. Ethosomes are lipid vesicular carriers containing ethanol which provides better penetration of drug into the skin. Etoricoxib is a non steroidal anti-inflammatory drug which has shown many side effects when used orally. Etoricoxib ethosomes were prepared by hot method using soya lecithin, ethanol, cholesterol and drug in different ratios. They were evaluated for particle size, entrapment efficiency and in vitro drug release. Optimized ethosomal formulation showed an entrapment efficiency of 88.09% and drug release of 90.4% in 8hrs. The optimized formulation was incorporated into gel using carbopol 934, HPMC K4M; HPMC K100.Optimized ethosomal gel (EG3 showed the drug content of 93.36% and drug release of 75.5% in 8hrs.Ex Vivo studies were performed for the optimized gel and the drug release was found to be 73.5%in 8hrs respectively. Stability studies indicated that optimized formulations were stable for a period of 3months under refrigerated conditions. It was concluded that Etoricoxib loaded ethosomal gels were successfully formulated to increase the efficacy and reduce its side effects.

  16. Comparative gel-based phosphoproteomics in response to signaling molecules

    Marondedze, Claudius

    2013-09-03

    The gel-based proteomics approach is a valuable technique for studying the characteristics of proteins. This technique has diverse applications ranging from analysis of a single protein to the study of the total cellular proteins. Further, protein quality and to some extent distribution can be first assessed by means of one-dimensional gel electrophoresis and then more informatively, for comparative analysis, using the two-dimensional gel electrophoresis technique. Here, we describe how to take advantage of the availability of fluorescent dyes to stain for a selective class of proteins on the same gel for the detection of both phospho- and total proteomes. This enables the co-detection of phosphoproteins as well as total proteins from the same gel and is accomplished by utilizing two different fluorescent stains, the ProQ-Diamond, which stains only phosphorylated proteins, and Sypro Ruby, which stains the entire subset of proteins. This workflow can be applied to gain insights into the regulatory mechanisms induced by signaling molecules such as cyclic nucleotides through the quantification and subsequent identification of responsive phospho- and total proteins. © Springer Science+Business Media New York 2013.

  17. System for loading slab-gel holders for electrophoresis separation

    Anderson, Norman G.; Anderson, Norman L.

    1979-01-01

    A slab-gel loading system includes a prismatic chamber for filling a plurality of slab-gel holders simultaneously. Each slab-gel holder comprises a pair of spaced apart plates defining an intermediate volume for gel containment. The holders are vertically positioned in the chamber with their major surfaces parallel to the chamber end walls. A liquid inlet is provided at the corner between the bottom and a side wall of the chamber for distributing a polymerizable monomer solution or a coagulable colloidal solution into each of the holders. The chamber is rotatably supported so that filling can begin with the corner having the liquid inlet directed downwardly such that the solution is gently funneled upwardly, without mixing, along the diverging side and bottom surfaces. As filling proceeds, the chamber is gradually rotated to position the bottom wall in a horizontal mode. The liquid filling means includes a plastic envelope with a septum dividing it into two compartments for intermixing two solutions of different density and thereby providing a liquid flow having a density gradient. The resulting gels have a density gradient between opposite edges for subsequent use in electrophoresis separations.

  18. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  19. Preparation of silica by sol-gel method using formamide

    R.F.S. Lenza

    2001-07-01

    Full Text Available In this work we obtained microporous and mesoporous silica gels by sol-gel processing. Tetraethylortosilicate (TEOS was used as precursor. Nitric acid and hydrofluoric acid were used as catalysts. In order to study the affect of formamide as drying additive, we used a molar ratio alkoxide/formamide of 1/1. The performance of formamide in obtaining crack-free gels was evaluated through monolithicity measurements. The structural evolution occurring in the interconnected network of the gels during thermal treatment was monitored by Fourier transform infrared spectroscopy (FTIR, shrinkage and density measurements and nitrogen gas sorption. We noted that in the presence of formamide, the Si-O-Si bonds are stronger and belong to a more cross-linked structure. The samples obtained in the presence of formamide have larger pore volume and its pore structure is in the range of mesoporosity. The samples obtained without additive are microporous. Formamide allowed the preparation of crack-free silica gels stabilized at high temperatures.

  20. Allopurinol gel mitigates radiation-induced mucositis and dermatitis

    It has not been verified whether allopurinol application is beneficial in decreasing the severity of radiation-induced oral mucositis and dermatitis. Rats were divided into 4 groups and received 15 Gy irradiation on the left whisker pad. Group 1 received only irradiation. Group 2 was maintained by applying allopurinol/carrageenan-mixed gel (allopurinol gel) continuously from 2 days before to 20 days after irradiation. Group 3 had allopurinol gel applied for 20 days after radiation. Group 4 was maintained by applying carrageenan gel continuously from 2 days before to 20 days after irradiation. The intra oral mucosal and acute skin reactions were assessed daily using mucositis and skin score systems. The escape thresholds for mechanical stimulation to the left whisker pad were measured daily. In addition, the irradiated tissues at the endpoint of this study were compared with naive tissue. Escape threshold in group 2 was significantly higher than that in group 1, and mucositis and skin scores were much improved compared with those of group 1. Concerning escape threshold, mucositis and skin scores in group 3 began to improve 10 days after irradiation. Group 4 showed severe symptoms of mucositis and dermatitis to the same extent as that observed in group 1. In the histopathological study, the tissues of group 1 showed severe inflammatory reactions, compared with those of group 2. These results suggest that allopurinol gel application can mitigate inflammation reactions associated with radiation-induced oral mucositis and dermatitis. (author)