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Comparative study of agar gel immunodiffusion (AGID protocols for the diagnosis of equine infectious anemia in Brazil  

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Full Text Available To evaluate the Equine Infectious Anemia (EIA agar gel immunodiffusion (AGID protocols, two different kits commercially available in Brazil were used: an imported kit (kit A and a domestically produced kit (kit B. Kit A was submitted to the protocols recommended by the World Organization for Animal Health (OIE and the protocol recommended by the Ministério da Agricultura Pecuária e Abastecimento (MAPA. Kit B, the Brazilian kit, was submitted only to the MAPA-recommended protocol and was used as a reference in this study. A total of 345 equid serum samples, including field samples, serum sets from official laboratories and a weak positive serum control from National Veterinary Services Laboratories (NVSL, were used. Parameters such as the sensitivity of kit A in the two protocols, the detection limit of kits and the occurrence of nonspecific reactions or non-identity were evaluated. When Kit A was used for an AGID procedure performed according to the OIE-recommended protocol, the kit demonstrated good agreement with kit B and 99 % relative sensitivity. However, when kit A was processed according to the MAPA-recommended protocol, it failed to detect 1.16 % of weak positive samples and its relative sensitivity decreased to 96 %. The detection limit of kit A was lower than the detection limit of kit B for weak positive samples in both protocols. The occurrence of nonidentity reactions was higher with kit B than with kit A. The training of veterinarians to ensure the correct execution of the AGID test protocol should be intensified in Brazil.

Fernanda Gonçalves Oliveira

2014-02-01

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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  

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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

Misbah Aslam

2009-06-01

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An enzyme-linked immunosorbent assay for detection of antibodies to maedi-visna virus in sheep. II. Comparison to conventional agar gel immunodiffusion test.  

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A study was conducted to compare the indirect enzyme-linked immunosorbent-assay (i-ELISA) test using antigen prepared by a simple technique using sodium dodecyl sulfate (SDS) treatment to the conventional agar gel immunodiffusion test (AGID). Ten specific-pathogen-free (SPF) sheep were inoculated with maedi-visna virus (MVV) and serum antibody titers compared over a period of 14 weeks. All the sheep seroconverted by the i-ELISA compared to 90% by the AGID. The i-ELISA detected antibody at a m...

Simard, C. L.; Briscoe, M. R.

1990-01-01

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Sensitivity and specificity of the agar-gel-immunodiffusion test, ELISA and the skin test for detection of paratuberculosis in United States Midwest sheep populations  

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Our objective was to estimate the sensitivity and specificity of the agar-gel-immunodiffusion test (AGID), the ELISA, and the skin test for the detection of Mycobacterium avium subspecies paratuberculosis (MAP) in sheep using Bayesian methods without a gold standard. Fourteen flocks (2 465 sheep) were used. Five flocks (450 sheep) were considered MAP non-infected and 9 flocks (2 015 sheep) had sheep infected with MAP. Sheep were skin tested and blood was collected for AGID and ELISA testing...

Robbe-austerman, Suelee; Gardner, Ian; Thomsen, Bruce; Morrical, Daniel; Martin, Barbara; Palmer, Mitchell; Thoen, Charles; Ewing, Chad

2006-01-01

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An enzyme-linked immunosorbent assay for detection of antibodies to maedi-visna virus in sheep. II. Comparison to conventional agar gel immunodiffusion test.  

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A study was conducted to compare the indirect enzyme-linked immunosorbent-assay (i-ELISA) test using antigen prepared by a simple technique using sodium dodecyl sulfate (SDS) treatment to the conventional agar gel immunodiffusion test (AGID). Ten specific-pathogen-free (SPF) sheep were inoculated with maedi-visna virus (MVV) and serum antibody titers compared over a period of 14 weeks. All the sheep seroconverted by the i-ELISA compared to 90% by the AGID. The i-ELISA detected antibody at a mean of 2.6 weeks prior to the AGID. In both tests, fluctuations were observed in the serum antibody response of two sheep. The i-ELISA had a specificity of at least 98.8% and an increased relative sensitivity of 15.5% compared to the AGID, based on the analysis of sera from experimental sheep with MVV free status and sera from sheep from various sources. Of the sera from a seronegative flock which had been monitored with the AGID after a "test and remove" eradication program, 10.2% were positive by the i-ELISA. It was concluded that the AGID test may not be adequate to monitor samples for an eradication scheme. PMID:2174296

Simard, C L; Briscoe, M R

1990-10-01

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Agar-gel immunodiffusion and rapid slide agglutination on canine brucellosis diagnosis Imunodifusão em gel de agar e soroaglutinação rápida para a detecção de anticorpos Anti-"Brucella canis"  

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Full Text Available The rapid slide agglutination test (SAT was compared to the agar gel immunodiffusion test (AGID for the canine brucellosis diagnosis in sera submitted or not to the treatment with 2-Mercaptoetanol. Among the 1,072 sera dogs examined in the study, 202 were positive by AGID test (18.84%, 9 by AGID 2-ME test (0.84%, 19 in the race for SAT (1, 77% and 9 in the race for SAT 2-ME (0.84%. The statistical evaluation of the results showed no significant difference among the tests of SAT, SAT 2-ME and AGID 2-ME, but differed significantly from AGID test.Este trabalho foi realizado com o objetivo de comparar as técnicas de soroaglutinação rápida em cartão (SAR e de imunodifusão em gel de ágar (IDGA, para o diagnóstico de brucelose canina em soros de cães submetidos ou não ao tratamento com 2-Mercaptoetanol. Dos 1.072 soros de cães examinados no estudo, verificaram-se reações positivas em 202 na prova de IDGA (18,84%, 9 na prova de IDGA 2-ME (0,84%; 19 na prova de SAR (1,77% e 9 na prova de SAR 2-ME (0,84%. A avaliação estatística dos resultados comprovou não haver diferença significativa entre os testes de SAR, SAR 2-ME e IDGA 2-ME, porém diferiram significativamente das obtidas no teste de IDGA.

Andre Marcelo Conceição Meneses

2009-03-01

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Recombinant envelope protein (rgp90) ELISA for equine infectious anemia virus provides comparable results to the agar gel immunodiffusion.  

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Equine infectious anemia (EIA) is an important viral infection affecting horses worldwide. The course of infection is accompanied generally by three characteristic stages: acute, chronic and inapparent. There is no effective EIA vaccine or treatment, and the control of the disease is based currently on identification of EIAV inapparent carriers by laboratory tests. Recombinant envelope protein (rgp90) was expressed in Escherichia coli and evaluated via enzyme-linked immunosorbent assay (ELISA). There was an excellent agreement (95.42%) between the ELISA results using rgp90 and agar gel immunodiffusion test results. AGID is considered the "gold-standard" serologic test for equine infectious anemia (EIA). After 1160 serum samples were tested, the relative sensitivity and specificity of the ELISA were 96.1% and 96.4%, respectively. Moreover, analysis diagnostic accuracy of the ELISA was performed. The ELISA proved robust. Furthermore, good reproducibility was observed for the negative controls and, positive controls for all plates tested. PMID:22227617

Reis, Jenner K P; Diniz, Rejane S; Haddad, João P A; Ferraz, Isabella B F; Carvalho, Alex F; Kroon, Erna G; Ferreira, Paulo C P; Leite, Rômulo C

2012-03-01

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Investigation on the status of Johne's disease based on agar gel immunodiffusion, ziehl-neelsen staining and nested PCR approach in two cattle farm  

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Full Text Available Background and Methods: Paratuberculosis is a chronic disease of ruminant, caused by Mycobacterium avium subsp. paratuberculosis (Map, clinically infected animals produce high level of antibodies in blood and shed detectable amount of Map organisms in feces. Several serological and molecular tests are utilized for detection of antibodies or DNA of the organism in clinical samples. Present study indicates the status of paratuberculosis in two distinct cattle farms with different organizational set-ups viz. organized and unorganized. We used agar gel immunodiffusion (AGID assay for the detection of antibodies in blood. Ziehl-Neelsen (ZN staining of fecal smears was done to observe acid-fast bacilli and Nested PCR targeted to IS900 and f57 sequences, was performed to confirm the pathogen.Results: Sera samples of cattle, from organized farm, did not show any visible precipitating band with AGID assay. However, fecal smears of few cattle (3.57% were positive for acid-fast bacilli. When confirmed with nested PCR, only one fecal sample (0.71% was found positive for Map. In case of unorganized farm, a large number of cattle (38.75% showed precipitating antibodies with AGID assay and the percentage of fecal smears that showed acid-fast bacilli was 26.62%. Nevertheless, fecal samples containing Map DNA was confirmed in 14.37% of fecal sample by nested PCR.Conclusions: An organized farm, with better hygiene and management practices, showed lesser occurrence of paratuberculosis in cattle in comparison to unorganized farm. Not all AGID assays positive cattle might be an efficient shedder of Map and mare detection of acid-fast bacilli in fecal smears did not always indicate the presence of Map organism. Cattle infected with JD were mostly in the age group of six years and above.

Anand Mohan,

2013-08-01

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Detecção da infecção pelo vírus da artrite-encefalite caprina: imunodifusão em ágar e reação em cadeia da polimerase com "primers" degenerados Detection of caprine arthritis-encephalitis virus infection: agar gel immunodiffusion and polymerase chain reaction with degenerated primers  

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Full Text Available O objetivo deste trabalho foi analisar amostras de soro e de células sangüíneas de caprinos para detecção de anticorpos e DNA proviral do vírus da artrite-encefalite caprina (CAEV, respectivamente. Utilizou-se a técnica de imunodifusão em ágar (AGID e a reação em cadeia da polimerase (PCR com "primers" degenerados. Foram analisadas amostras de diferentes procedências: 39 de Mato Grosso do Sul (MS, 19 de São Paulo (SP e 22 do Ceará (CE, dessas últimas, 12 oriundas de animais importados do Canadá. Os resultados de AGID e PCR foram discordantes, pois o primeiro permitiu a detecção de 25 animais soropositivos, enquanto a PCR detectou DNA proviral de CAEV em 16 amostras. Pela PCR foi possível identificar animais infectados cujos testes sorológicos foram negativos pelo AGID: oito amostras do MS e um do CE. São discutidos diferentes aspectos que poderiam estar envolvidos na discordância dos resultados.The purpose of this work was to analyse serum and blood cells from caprine origin to detect antibody and proviral DNA of caprine arthritis encephalitis virus (CAEV, respectively. Agar gel immunodiffusion (AGID and polymerase chain reaction (PCR with degenerated primers were used. Samples of different geographical regions were analysed: 39 from Mato Grosso do Sul (MS, 19 from São Paulo (SP, 22 from Ceará (CE including 10 from Canada (imported animals, providing a total of 80 samples. The results obtained by AGID and PCR were discordants, as 25 samples were detected as seropositive, while 16 infected animals were detected by PCR. On the other hand, PCR allowed the identification of infected animals that did not have detectable antibodies by AGID: eight samples from MS and one from CE. Different aspects related to these discordant results are discussed.

J.K. Rutkoski

2001-12-01

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Detecção da infecção pelo vírus da artrite-encefalite caprina: imunodifusão em ágar e reação em cadeia da polimerase com "primers" degenerados / Detection of caprine arthritis-encephalitis virus infection: agar gel immunodiffusion and polymerase chain reaction with degenerated primers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste trabalho foi analisar amostras de soro e de células sangüíneas de caprinos para detecção de anticorpos e DNA proviral do vírus da artrite-encefalite caprina (CAEV), respectivamente. Utilizou-se a técnica de imunodifusão em ágar (AGID) e a reação em cadeia da polimerase (PCR) com "pr [...] imers" degenerados. Foram analisadas amostras de diferentes procedências: 39 de Mato Grosso do Sul (MS), 19 de São Paulo (SP) e 22 do Ceará (CE), dessas últimas, 12 oriundas de animais importados do Canadá. Os resultados de AGID e PCR foram discordantes, pois o primeiro permitiu a detecção de 25 animais soropositivos, enquanto a PCR detectou DNA proviral de CAEV em 16 amostras. Pela PCR foi possível identificar animais infectados cujos testes sorológicos foram negativos pelo AGID: oito amostras do MS e um do CE. São discutidos diferentes aspectos que poderiam estar envolvidos na discordância dos resultados. Abstract in english The purpose of this work was to analyse serum and blood cells from caprine origin to detect antibody and proviral DNA of caprine arthritis encephalitis virus (CAEV), respectively. Agar gel immunodiffusion (AGID) and polymerase chain reaction (PCR) with degenerated primers were used. Samples of diffe [...] rent geographical regions were analysed: 39 from Mato Grosso do Sul (MS), 19 from São Paulo (SP), 22 from Ceará (CE) including 10 from Canada (imported animals), providing a total of 80 samples. The results obtained by AGID and PCR were discordants, as 25 samples were detected as seropositive, while 16 infected animals were detected by PCR. On the other hand, PCR allowed the identification of infected animals that did not have detectable antibodies by AGID: eight samples from MS and one from CE. Different aspects related to these discordant results are discussed.

J.K., Rutkoski; R., Werenicz; D., Reischak; A.C., Wendelstein; V., Moojen; A.P., Ravazzolo.

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Improvements to the hemagglutination inhibition test for serological assessment of recombinant fowlpox-H5-avian-influenza vaccination in chickens and its use along with an agar gel immunodiffusion test for differentiating infected from noninfected vaccinated animals.  

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In general, avian influenza (AI) vaccines protect chickens from morbidity and mortality and reduce, but do not completely prevent, replication of wild AI viruses in the respiratory and intestinal tracts of vaccinated chickens. Therefore, surveillance programs based on serological testing must be developed to differentiate vaccinated flocks infected with wild strains of AI virus from noninfected vaccinated flocks in order to evaluate the success of vaccination in a control program and allow continuation of national and international commerce of poultry and poultry products. In this study, chickens were immunized with a commercial recombinant fowlpox virus vaccine containing an H5 hemagglutinin gene from A/turkey/Ireland/83 (H5N8) avian influenza (AI) virus (rFP-H5) and evaluated for correlation of immunological response by hemagglutination inhibition (HI) or agar gel immunodiffusion (AGID) tests and determination of protection following challenge with a high pathogenicity AI (HPAI) virus. In two different trials, chickens immunized with the rFP-H5 vaccine did not develop AGID antibodies because the vaccine lacks AI nucleoprotein and matrix genes, but 0%-100% had HI antibodies, depending on the AI virus strain used in the HI test, the HI antigen inactivation procedure, and whether the birds had been preimmunized against fowlpox virus. The most consistent and highest HI titers were observed when using A/turkey/Ireland/83 (H5N8) HPAI virus strain as the beta-propiolactone (BPL)-inactivated HI test antigen, which matched the hemagglutinin gene insert in the rFP-H5 vaccine. In addition, higher HI titers were observed if ether or a combination of ether and BPL-inactivated virus was used in place of the BPL-inactivated virus. The rFP-H5 vaccinated chickens survived HPAI challenge and antibodies were detected by both AGID and HI tests. In conclusion, we demonstrated that the rFP-H5 vaccine allowed easy serological differentiation of infected from noninfected birds in vaccinated populations of chickens when using standard AGID and HI tests. PMID:17992929

Swayne, David E; Avellaneda, Gloria; Mickle, Thomas R; Pritchard, Nikki; Cruz, Julio; Bublot, Michel

2007-09-01

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

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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

A. Manicavasaka Dinakaran

2010-10-01

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

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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

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Is a diagnostic system based exclusively on agar gel immunodiffusion adequate for controlling the spread of equine infectious anaemia?  

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To improve the efficiency of the National equine infectious anaemia (EIA) surveillance program in Italy, a three-tiered diagnostic system has been adopted. This procedure involves initial screening by ELISA (Tier 1) with test-positive samples confirmed by the agar gel immunodiffusion test (AGIDT) (Tier 2) and, in the case of ELISA positive/AGIDT negative results, final determination by immunoblot (IB) (Tier 3). During this evaluation, 74,880 samples, principally collected from two Regions of Central Italy (Latium and Abruzzo) were examined, with 44 identified as negative in AGIDT but positive in both ELISA and IB. As the majority of these reactions occurred in mules, an observational study was conducted in this hybrid equid species to investigate if there is a correlation between plasma-associated viral loads and serological reactivity, to test the hypothesis that false-negative or very weak positive AGIDT results are associated with elite control of EIA virus (EIAV) replication accompanied by reduced transmission risks. The study animals consisted of 5 mules with positive AGIDT readings, along with another 5 giving negative or very weak positive results in this test. All mules were seropositive in Elisa and IB. Samples were collected routinely during an initial 56-day observation period, prior to dexamethasone treatment lasting 10 days, to determine the effect of immune suppression (IS) on clinical, humoral and virological responses. All mules were monitored for a further 28 days from day 0 of IS. None of the animals experienced relevant clinical responses before IS and there were no significant changes in antibody levels in ELISA, IB or AGIDT. However, plasma-associated viral-RNA (vRNA) loads, as determined using TaqMan(®) based RT-PCR, showed unexpectedly high sample to sample variation in all mules, demonstrating host-mediated control of viral replication is not constant over time. Furthermore, there was no apparent correlation between vRNA loads and antibody reactivity in serological tests. Analysis of PCR products established all mules were infected with viruses possessing nucleotide sequence similarity, varying from 77 to 96%, to previously identified European EIAV strains. Following IS, all mules showed increases in plasma-associated vRNA loads, suggesting control of EIAV replication is mediated by immune responses in this hybrid species. However, only three mules showed anamnestic humoral responses to rises in viral loads, as defined by at least a four-fold increase in ELISA titre, while two remained AGIDT-negative. This study demonstrates that viral loads in equids with consistent ELISA/IB positive-AGIDT negative to very weak positive test results (Group N) can be equivalent to those that produce clearly positive results in all three serologic tests (Group P). Therefore, such animals do not pose inherently lower risks for the transmission of EIAV. Consequently, the exclusive use of the AGIDT, as prescribed by the World Organization of Animal Health (OIE) for diagnosis of EIA prior to the international movement of horses, can report as negative some EIAV-infected equids. These results dramatically underscore the necessity of combining the specificity of AGIDT with tests with higher sensitivity, such as the ELISA and the power of the IB to enhance the accuracy of EIA diagnosis. PMID:23618837

Scicluna, Maria Teresa; Issel, Charles J; Cook, Frank R; Manna, Giuseppe; Cersini, Antonella; Rosone, Francesca; Frontoso, Raffaele; Caprioli, Andrea; Antognetti, Valeria; Antonetti, Valeria; Autorino, Gian Luca

2013-07-26

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Produção de antígeno nucleoprotéico do vírus da artrite-encefalite caprina e comparação com o do vírus Maedi-Visna para utilização em teste de imunodifusão em ágar gel CAEV nucleoproteic antigen production and comparison with Maedi-Visna antigen in the immunodiffusion test  

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Full Text Available Foi feita uma comparação entre os antígenos (Ag, preparados a partir dos vírus Maedi-Visna (MVV e Artrite-encefalite Caprina (CAEV para detecção de anticorpos contra o CAEV em 120 amostras de soro caprino. A sensibilidade e especificidade relativa da imunodifusão em ágar gel (IDAG usando-se Ag MVV em relação ao Ag CAEV, foi 77,3% e 100%, respectivamente (X2, pA comparison of Maedi-Visna virus (MVV and Caprine Arthritis-encephalitis virus (CAEV antigens for detection of antibodies to CAEV was performed using sera from 120 goats. The sensitivity and specificity of the immunodiffusion test using MVV antigen compared to that of CAEV antigen was 77.3% and 100%, respectively (X2, p < 0.01. These results suggested that only CAEV antigen should be used in immunodiffusion tests for CAEV diagnosis.

Silvio R. O. Abreu

1998-04-01

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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  

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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.

Cristiane Nakada Nozaki

2011-08-01

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Produção de antígeno nucleoprotéico do vírus da artrite-encefalite caprina e comparação com o do vírus Maedi-Visna para utilização em teste de imunodifusão em ágar gel / CAEV nucleoproteic antigen production and comparison with Maedi-Visna antigen in the immunodiffusion test  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foi feita uma comparação entre os antígenos (Ag), preparados a partir dos vírus Maedi-Visna (MVV) e Artrite-encefalite Caprina (CAEV) para detecção de anticorpos contra o CAEV em 120 amostras de soro caprino. A sensibilidade e especificidade relativa da imunodifusão em ágar gel (IDAG) usando-se Ag M [...] VV em relação ao Ag CAEV, foi 77,3% e 100%, respectivamente (X2, p Abstract in english A comparison of Maedi-Visna virus (MVV) and Caprine Arthritis-encephalitis virus (CAEV) antigens for detection of antibodies to CAEV was performed using sera from 120 goats. The sensitivity and specificity of the immunodiffusion test using MVV antigen compared to that of CAEV antigen was 77.3% and 1 [...] 00%, respectively (X2, p

Silvio R. O., Abreu; Roberto S., Castro; Sérgio A., Nascimento; Marleide G., Souza.

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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  

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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, whereas 25 negative animals by AGID were considered positive by the ELISA test, in both biological samples. Thus, sensitivity of the ELISA with respect to AGID was 100%, whereas specificity was 51% (kappa 0.55. The smaller sensitivity of AGID is not due to false positive reactions of ELISA and PCR tests, but rather to a greater sensitivity of these, which suggests a revision of AGID in those countries in which it is still used as the official method in the erradication programs of leukaemia.

R Felmer

2006-01-01

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9 CFR 147.9 - Standard test procedures for avian influenza.  

Science.gov (United States)

... Standard test procedures for avian influenza. 147.9 Section 147.9... Standard test procedures for avian influenza. (a) The agar gel immunodiffusion...A-6877 or equivalent). (iii) Avian influenza AGID antigen and positive...

2010-01-01

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Immunodiffusion test for diagnosing and monitoring pythiosis in horses.  

Science.gov (United States)

A practical, sensitive, and specific immunodiffusion test was developed for diagnosing and monitoring pythiosis in horses. Culture filtrates, a soluble cell mass, and trypsinized Pythium sp. antigens were evaluated against prepared rabbit anti-Pythium sp. serum and pythiosis horse case sera. The culture filtrate antigens demonstrated the greatest capacity for detecting precipitins and the greatest stability during storage. In contrast, the trypsinized antigens had the weakest capability for detecting multiple precipitins and the poorest stability. The 13 sera from horses with proven active pythiosis were positive in immunodiffusion tests with the culture filtrate antigens. Each serum contained from three to six precipitins. Treated horses lost precipitins, and some became antibody negative. No false-positive reactions were noted in tests with sera from normal horses and humans or with sera from a variety of heterologous horse and human infections. Images PMID:3086368

Mendoza, L; Kaufman, L; Standard, P G

1986-01-01

 
 
 
 
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Immunodiffusion test for diagnosis and monitoring of human pythiosis insidiosi.  

Science.gov (United States)

To facilitate the laboratory diagnosis of human cases of pythiosis insidiosi, an immunological test was evaluated. A soluble antigen was prepared from a human isolate of Pythium insidiosum, an aquatic, thermotolerant oomycete that causes infections in cattle, dogs, horses, and humans. Sera from seven proven cases of disseminated human pythiosis insidiosi were tested in an immunodiffusion test along with appropriate control sera from patients with a variety of actinomycotic, bacterial, and mycotic diseases as well as sera from uninfected individuals. Titers ranged from 1:1 to 1:32 in the seven serum samples from the disseminated cases of pythiosis insidiosi of varying severity. The heterologous sera gave negative reactions. The rapidity and specificity of the immunodiffusion test makes it a useful diagnostic tool for the serodiagnosis of P. insidiosum infections. PMID:1774283

Pracharktam, R; Changtrakool, P; Sathapatayavongs, B; Jayanetra, P; Ajello, L

1991-01-01

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A comparison of two agar gel immunodiffusion methods and a complement fixation test for serologic diagnosis of Brucella ovis infection in experimentally infected rams / Comparação entre dois métodos de imunodifusão em gel de Agar e um método de fixação de complemento para o diagnóstico sorológico da infecção por Brucella ovis em carneiros experimentalmente infectados  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A infecção por Brucella ovis é considerada uma das principais causas de epididimite e infertilidade em carneiros, resultando em falhas reprodutivas e perdas econômicas significativas em rebanhos ovinos ao redor do mundo. O estudo teve o objetivo de avaliar três testes sorológicos disponíveis para o [...] diagnóstico da brucelose ovina por B. ovis, utilizando 181 soros ovinos. Amostras de soro provenientes de carneiros experimentalmente infectados foram coletadas ao longo de 192 dias pós-infecção (n=117) e durante o período pré-infecção (n=9). Adicionalmente, amostras de soro foram obtidas de ovinos provenientes de um rebanho livre para B. ovis (n=55). As técnicas de imunodifusão em gel de agar (IDGA), utilizando dois antígenos disponíveis comercialmente, e de fixação de complemento foram comparadas (FC). Foram obtidos resultados de sensibilidade especificidade semelhantes para ambos os métodos de IDGA e ainda, a técnica de IDGA foi mais eficiente do que a da FC para o diagnóstico sorológico da infecção por B. ovis. Abstract in english [...

M.N., Xavier; F.M., Sant' Anna; T.M.A., Silva; E.A., Costa; V.S., Moustacas; F.A., Merlo; C.A., Carvalho Júnior; M.G., Dasso; L.A., Mathias; A.M.G., Gouveia; A.P., Lage; R.L., Santos.

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

Science.gov (United States)

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

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

1976-01-01

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Autoantibody testing for connective tissue diseases. Comparison of immunodiffusion, immunoblot, and enzyme immunoassay.  

Science.gov (United States)

We evaluated 500 consecutive patient serum samples for the presence of six autoantibodies by three antibody detection methods: immunodiffusion, immunoblot, and enzyme immunoassay. Clinical data were reviewed for each patient with positive antibody test results. Serum samples from 60 patients revealed antibodies to Sm, ribonucleoprotein (RNP), SSA/Ro, SSB/La, Scl-70, or Jo-1. There were 7 false-positive test results (1%). All three methods detected autoantibodies in 36 (68%) of 53 patients with connective tissue disease. Immunoblot was the most sensitive method to detect autoantibodies (92%). Enzyme immunoassay and immunodiffusion were less sensitive (81% and 74%, respectively). Antiribonucleoprotein and anti-SSB/La antibodies were more often detected by immunoblotting, whereas anti-SSA/Ro antibodies were more often detected by enzyme immunoassay. Newer antibody detection methods (immunoblot and enzyme immunoassay) are less time consuming than immunodiffusion and show good interassay sensitivity without loss of specificity. A combination of immunoblot and enzyme immunoassay yielded excellent assay sensitivity (100%) and specificity (99%) for detection of autoantibodies. PMID:9322593

Bridges, A J; Lorden, T E; Havighurst, T C

1997-10-01

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Comparison of serological methods for the diagnostic of Caprine arthritis-encephalitis (CAE in Rio de Janeiro, Brazil Comparação entre métodos sorológicos para o diagnóstico da Artrite-encefalite caprina (CAE no Rio de Janeiro, Brasil  

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Full Text Available Serum samples of 562 goats were tested for Caprine arthritis-encephalitis using agar gel immunodiffusion test (AGID and enzyme linked immunosorbent assay (ELISA. Seventy-nine samples (14.1% were reactive by both testes but 141 (25.1% were reactive only by ELISA. ELISA, when compared to AGID, presented 100% sensitivity and 70.8% specificity.Soros de 562 caprinos foram submetidos à pesquisa de Artrite-encefalite caprina através dos testes de imunodifusão em gel de agarose (AGID de teste imunoenzimático (ELISA. Das amostras testadas, 79 (14,1% foram reativas em ambos os testes, mas 141 (25,1% foram positivos apenas no ELISA. Assim, a sensibilidade do ELISA em relação ao AGID foi de 100% e a especificidade de 70,8%.

Madelayne Cortez-Moreira

2005-03-01

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Determination of thyroxine-binding globulin in human serum by single radial immunodiffusion and radioimmunoassay  

International Nuclear Information System (INIS)

Two immunochemical methods for determination of thyroxine-binding globulin in human serum were developed, in which the purified globulin and monospecific antiserum to it are used. One method, based on radial immunodiffusion, has good precision and values for analytical recovery. Reference values obtained for men were 9.8 to 17.8 mg/liter and for women 11.3 to 20.5 mg/liter. The sex-related difference was significant. The other method is based on radioimmunoassay, with use of an iodinated acylating agent for the labeling of thyroxine-binding globulin. The relative merits of the two methods are discussed

27

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

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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.

MICELI Graciela S.

2000-01-01

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The feasibility of using antigens prepared with rough Brucella strains for diagnosis of canine brucellosis Utilidad de los antígenos preparados con cepas rugosas de Brucella en el diagnóstico de brucelosis canina  

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Clinical diagnosis of canine brucellosis is not sensitive enough and a negative blood culture cannot rule out the disease. Indirect methods of serological testing such as agar gel immunodiffusion (AGID), rapid slide agglutination test (RSAT) and indirect enzyme linked immunoassay (IELISA) are preferred for routine diagnosis. Since Brucella canis shares antigenic components with the Brucella ovis and Brucella abortus RB51 strain, it would seem that either strain could be used as antigen. We pr...

Escobar, G. I.; Boeri, E. J.; Ayala, S. M.; Lucero, N. E.

2010-01-01

29

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

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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.

K.C. Sahna

2012-05-01

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Measurement of serum immunoglobulin concentration in killer whales and sea otters by radial immunodiffusion.  

Science.gov (United States)

Killer whales and sea otters maintained in captivity are the subjects of routine health monitoring programs, and interest in immunologic studies in sea otters has been rising recently in response to potential impacts from infectious disease and environmental pollution on the threatened southern sea otter population. Development of species-specific reagents for immunologic studies in these two marine mammals is currently in its infancy. In this study, killer whale and sea otter immunoglobulin-specific polyclonal antibodies were generated, and used to develop tests for serum Ig concentration in the killer whale (Orcinus orca) and the southern (Enhydra lutris nereis) and northern sea otter (Enhydra lutris lutris). Killer whale serum IgG was purified using caprylic acid/ammonium sulfate precipitation. Sea otter plasma IgG was purified using protein-A-agarose. Polyclonal anti-Ig antisera were produced in rabbits, and specificity confirmed by immunoelectrophoresis. Radial immunodiffusion was used to measure Ig concentration in serum or plasma samples derived from 21 captive killer whales, 18 wild and 4 captive southern sea otters and 15 wild and 4 captive northern sea otters grouped by age. Mean killer whale serum Ig concentration (+/-95% confidence interval) ranged from 15.04 +/- 3.97 g/l for animals aged 0-5 years to 26.65 +/- 9.8 g/l for animals aged >10 years. Mean sea otter serum Ig concentration (+/-95% confidence interval) ranged from 28.39 +/- 11.00 g/l for southern sub-adults to 32.76 +/- 11.58 g/l for southern adults. No significant difference in serum Ig concentration was found between southern and northern sea otters. Serum Ig concentrations in two northern sea otter pups were low compared to those of adult sea otters. The two serum Ig quantitation assays produced were highly specific and reproducible and will be useful additions to the limited number of tests available for immune function in these marine mammal species. PMID:12383650

Taylor, Bernadette C; Brotheridge, Rory M; Jessup, David A; Stott, Jeffrey L

2002-10-28

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Avaliação da nested PCR em comparação aos testes sorológicos IDGA e ELISA para o diagnóstico da anemia infecciosa equina Evaluation of nested PCR compared with AGID and ELISA serological tests for equine infectious anemia diagnosis  

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Full Text Available Comparou-se a técnica nested PCR (nPCR com os testes sorológicos IDGA e ELISA para o diagnóstico da anemia infecciosa equina. Amostras do DNA provenientes das células mononucleares do sangue periférico foram submetidas à amplificação do gene gag pela nPCR, que apresentou valores de sensibilidade e especificidade relativas de 90% e 52,9%, respectivamente, em relação à IDGA, e valores de 85,7% e 49%, respectivamente, em relação ao ELISA. Considerando-se os fatores referentes às limitações de cada técnica, pode ser sugerido o uso da nPCR como teste de diagnóstico complementar para AIE em amostras brasileiras.The nested polymerase chain reaction (nPCR technique was compared to AGID and ELISA serological tests for the diagnosis of Equine Infectious Anemia. DNA samples from the peripheral blood mononuclear cells were subjected to the amplification of the gag gene by nPCR, which showed relative sensibility and specificity values of 90.0% and 52.9% respectively, compared to the AGID and values of 85.7% and 49.0%, respectively, as compared to ELISA. Considering the factors concerning the limitations of each technique, the use of nPCR can be suggested as a complementary diagnostic test for EIA in Brazilian samples.

E.M. Santos

2011-04-01

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Avaliação da nested PCR em comparação aos testes sorológicos IDGA e ELISA para o diagnóstico da anemia infecciosa equina / Evaluation of nested PCR compared with AGID and ELISA serological tests for equine infectious anemia diagnosis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Comparou-se a técnica nested PCR (nPCR) com os testes sorológicos IDGA e ELISA para o diagnóstico da anemia infecciosa equina. Amostras do DNA provenientes das células mononucleares do sangue periférico foram submetidas à amplificação do gene gag pela nPCR, que apresentou valores de sensibilidade e [...] especificidade relativas de 90% e 52,9%, respectivamente, em relação à IDGA, e valores de 85,7% e 49%, respectivamente, em relação ao ELISA. Considerando-se os fatores referentes às limitações de cada técnica, pode ser sugerido o uso da nPCR como teste de diagnóstico complementar para AIE em amostras brasileiras. Abstract in english The nested polymerase chain reaction (nPCR) technique was compared to AGID and ELISA serological tests for the diagnosis of Equine Infectious Anemia. DNA samples from the peripheral blood mononuclear cells were subjected to the amplification of the gag gene by nPCR, which showed relative sensibility [...] and specificity values of 90.0% and 52.9% respectively, compared to the AGID and values of 85.7% and 49.0%, respectively, as compared to ELISA. Considering the factors concerning the limitations of each technique, the use of nPCR can be suggested as a complementary diagnostic test for EIA in Brazilian samples.

E.M., Santos; P.M.C., Motta; M.B., Heinemann; R.C., Leite; J.K.P., Reis.

2011-04-01

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

International Nuclear Information System (INIS)

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.)

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Specific determination of N-acetyl-?-D-hexosaminidase isozymes A and B by radioimmunoassay and radial immunodiffusion  

International Nuclear Information System (INIS)

The two major isozymes of N-acetylhexosaminidase, namely hexosaminidase A and B were quantitatively determined in tissues and biological fluids of both normal individuals and Tay-Sachs patients. The determination was carried out by two sensitive immunoassays: radial immunodiffusion, using chromogenic substrate, and radioimmunoassay, which were developed in this study. For this purpose we used either a cross-reactive antiserum which reacts to a similar extent with both isozymes, or an antiserum reacting exclusively with hexosaminidase A (obtained by selective immunoadsorption). This enabled the quantitisation of the two isozymes separately, or in the presence of each other, in purified enzyme preparations or in tissue homogenates, affording a direct positive determination of hexosaminidase A. The results demonstrated that normal tissues contain the two isozymes in comparable amounts, whereas tissues of Tay-Sachs patients lack hexosaminidase A or any material which carries the A-specific antigenic determinants. The possible applications of these assays and their potential diagnosis are discussed. (orig.)

35

Epidemiological studies on bluetongue virus infection in West Java, Indonesia  

International Nuclear Information System (INIS)

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

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Performance comparison of immunodiffusion, enzyme-linked immunosorbent assay, immunochromatography and hemagglutination for serodiagnosis of human pythiosis.  

Science.gov (United States)

Pythiosis is a life-threatening infectious disease caused by the fungus-like organism Pythium insidiosum. Morbidity and mortality rates of pythiosis are high. The treatment of choice for pythiosis is surgical debridement of infected tissue. Early and accurate diagnosis is critical for effective treatment. In-house serodiagnostic tests, including immunodiffusion (ID), enzyme-linked immunosorbent assay (ELISA), immunochromatography (ICT) and hemagglutination (HA) have been developed to detect antibodies against P. insidiosum in sera. This study compares the diagnostic performance of ID, ELISA, ICT, and HA, using sera from 37 pythiosis patients and 248 control subjects. ICT and ELISA showed optimal diagnostic performance (100% sensitivity, specificity, positive predictive value and negative predictive value). ICT was both rapid and user-friendly. ELISA results were readily quantitated. ID is relatively insensitive. HA was rapid, but diagnostic performance was poor. Understanding the advantages offered by each assay facilitates selection of an assay that is circumstance-appropriate. This will promote earlier diagnoses and improved outcomes for patients with pythiosis. PMID:23537786

Chareonsirisuthigul, Takol; Khositnithikul, Rommanee; Intaramat, Akarin; Inkomlue, Ruchuros; Sriwanichrak, Kanchana; Piromsontikorn, Savittree; Kitiwanwanich, Sureewan; Lowhnoo, Tassanee; Yingyong, Wanta; Chaiprasert, Angkana; Banyong, Ramrada; Ratanabanangkoon, Kavi; Brandhorst, Tristan T; Krajaejun, Theerapong

2013-05-01

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Gel Electrophoresis  

Science.gov (United States)

In the early days of DNA manipulation, DNA fragments were laboriously separated by gravity. In the 1970s, the powerful tool of DNA gel electrophoresis was developed. This process uses electricity to separate DNA fragments by size as they migrate through a gel matrix. This animation from Cold Spring Harbor Laboratory's Dolan DNA Learning Center presents Gel Electrophoresis through a series of illustrations of the processes involved.

2012-01-20

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Chitin gels.  

Science.gov (United States)

Chitin dissolved in N,N-dimethylacetamide, N-methyl-2-pyrrolidone and their mixed solvents in the presence of 5% LiCl was treated with acetic anhydride-pyridine, and the mixture solution was heated at 100 degrees C for 6 h to give a partially O-acetylated chitin gel. Chitin dissolved in these solvents in the presence of 5% LiCl was mixed with pyridine, and the mixture solution was heated at 60 degrees C for 5 h to give a chitin gel. Both the gels were rigid and transparent, and their properties and the rate of the hydrolysis of the chitin xerogel by hen-egg white lysozyme were essentially similar to those of N-acetylchitosan gel prepared by chemical N-acetylation of chitosan. PMID:2562247

Hirano, S; Horiuchi, K

1989-08-01

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Large-scale serological survey of caprine arthritis-encephalitis virus (CAEV) in Korean black goats (Capra hircus aegagrus).  

Science.gov (United States)

A national serological survey of caprine arthritis-encephalitis virus (CAEV) infection was conducted using an enzyme-linked immunosorbent assay (ELISA) and an agar gel immunodiffusion (AGID) test. A total of 658 black goats of various breeds were sampled from 59 farms in three regions of Korea. The CAEV-positive goats were predominantly detected in the Southern region (n=17) as compared with the Northern (n=1) and Central regions (n=0) (?(2)=6.26, P=0.044). Among 658 goats tested, 18 were positive in both ELISA and AGID, indicating a CAEV prevalence of 2.73% (95% confidence interval: 1.74-4.28). These results indicate that CAEV is present in Korean black goats. PMID:22814087

Oem, Jae-Ku; Chung, Joon-Yee; Byun, Jae-Won; Kim, Ha-Young; Kwak, Dongmi; Jung, Byeong Yeal

2012-12-01

40

Aerosol gels  

Science.gov (United States)

An improved process for the production of ultralow density, high specific surface area gel products is provided which comprises providing, in an enclosed chamber, a mixture made up of small particles of material suspended in gas; the particles are then caused to aggregate in the chamber to form ramified fractal aggregate gels. The particles should have a radius (a) of up to about 50 nm and the aerosol should have a volume fraction (f.sub.v) of at least 10.sup.-4. In preferred practice, the mixture is created by a spark-induced explosion of a precursor material (e.g., a hydrocarbon) and oxygen within the chamber. New compositions of matter are disclosed having densities below 3.0 mg/cc.

Sorensen, Christopher M. (Inventor); Chakrabarti, Amitabha (Inventor); Dhaubhadel, Rajan (Inventor); Gerving, Corey (Inventor)

2010-01-01

 
 
 
 
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Development and qualification of the parallel line model for the estimation of human influenza haemagglutinin content using the single radial immunodiffusion assay.  

Science.gov (United States)

Infection with human influenza virus leads to serious respiratory disease. Vaccination is the most common and effective prophylactic measure to prevent influenza. Influenza vaccine manufacturing and release is controlled by the correct determination of the potency-defining haemagglutinin (HA) content. This determination is historically done by single radial immunodiffusion (SRID), which utilizes a statistical slope-ratio model to estimate the actual HA content. In this paper we describe the development and qualification of a parallel line model for analysis of HA quantification by SRID in cell culture-derived whole virus final monovalent and trivalent influenza vaccines. We evaluated plate layout, sample randomization, and validity of data and statistical model. The parallel line model was shown to be robust and reproducible. The precision studies for HA content demonstrated 3.8-5.0% repeatability and 3.8%-7.9% intermediate precision. Furthermore, system suitability criteria were developed to guarantee long-term stability of this assay in a regulated production environment. SRID is fraught with methodological and logistical difficulties and the determination of the HA content requires the acceptance of new and modern release assays, but until that moment, the described parallel line model represents a significant and robust update for the current global influenza vaccine release assay. PMID:22107849

van Kessel, G; Geels, M J; de Weerd, S; Buijs, L J; de Bruijni, M A M; Glansbeek, H L; van den Bosch, J F; Heldens, J G; van den Heuvel, E R

2012-01-01

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

Science.gov (United States)

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.

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

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

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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.

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

2011-06-01

44

Temperature responsive gel displays  

Science.gov (United States)

Synthesis and application of engineered surface patterns on environmentally responsive polymer gels are reported here. N-isopropylacrylamide (NIPA) gel was deposited on the masked-surface of an acrylamide gel using photo-initiated polymerization method. The pattern of the NIPA deposited area can be either visible or invisible by simply switching temperature above or below the low critical solution temperature (LCST) of the NIPA gel. Such gels can be used as displays.

Zheng, Yindong; Wang, Changjie; Hu, Zhibing; Li, Yong

1999-10-01

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Detection of Brucella ovis in ovine from Paraíba State, in the Northeast region of Brazil  

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Full Text Available To determine the presence of Brucella ovis in ovine from Paraíba State, in the Northeast region of Brazil, 80 animals slaughtered in the public slaughterhouse of Patos city were used. Before slaughter, blood samples were collected by jugular venopuncture from each animal, and after slaughter, testicles, epidydimus and uterus were aseptically collected. For the serological diagnosis of B. ovis and B. abortus infections, the agar gel immunodiffusion (AGID and Rose Bengal (RBT tests were carried out, respectively. In addition, microbiological culture and polymerase chain reaction (PCR were performed on testicle, epidydimus and uterus samples. Six animals (7.5% tested positive for the presence of B. ovis antibodies and all animals tested negative for the presence of B. abortus antibodies. One AGID-positive animal tested positive at uterine swab culture. PCR was able to amplify DNA of Brucella spp. from the pool of testicle, epidydimus and uterus samples from AGID-positive animals. This is the first report of isolation and detection of B. ovis DNA by PCR in ovine from the Northeast region of Brazil.

Clebert José Alves

2010-06-01

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

Science.gov (United States)

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

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

2014-11-01

47

Blastomycosis in nondomestic felids.  

Science.gov (United States)

Blastomycosis was diagnosed in six nondomestic felids from eastern Tennessee, including two Asian lions (Panthera leo persicus), one African lion (Panthera leo), one Siberian tiger (Panthera tigris), one cheetah (Acinonyx jubatus), and one snow leopard (Panthera uncia). Clinical signs included lethargy, anorexia, weight loss, dyspnea, sneezing. ataxia, and paresis. Variable nonspecific changes included leukocytosis, monocytosis, moderate left shift of neutrophils, moderate hypercalcemia, hyperproteinemia, and hyperglobulinemia. Thoracic radiographs revealed interstitial and alveolar changes, consolidation or collapse of a lung lobe, bullae formation, and a pulmonary mass. Agar gel immunodiffusion (AGID) serology for Blastomyces dermatitidis was performed in five felids and was positive in three. The tiger had cerebral blastomycosis and was positive for AGID serologic tests of both cerebrospinal fluid and serum. One percutaneous lung aspirate in the snow leopard and one bronchial aspirate in an Asian lion demonstrated B. dermatitidis organisms. whereas tracheal wash samples and a nasal discharge were nondiagnostic in others. Treatment with itraconazole was attempted in four cats. The tiger improved before euthanasia, whereas the others did not survive beyond initial treatments. In four felids, B. dermatitidis was found in the lungs and tracheobronchial lymph nodes associated with a florid pyogranulomatous reaction; the tiger had a pyogranulomatous encephalomyelitis, and the cheetah had a single pulmonary granuloma. Thoracic radiography, cytologic examination of lung lesion aspirates, and B. dermatitidis AGID serology should be performed on clinically ill zoo felids in endemic areas to rule out blastomycosis. PMID:14582783

Storms, Timothy N; Clyde, Victoria L; Munson, Linda; Ramsay, Edward C

2003-09-01

48

Running an Agarose Gel  

Science.gov (United States)

This video adapted from the University of Leicester provides step-by-step instructions for loading samples into an agarose gel and then running the gel to separate DNA molecules according to their size.

Foundation, Wgbh E.

2011-11-07

49

Removing water from gels  

International Nuclear Information System (INIS)

Water is removed from a gel material by contacting the gel material with an organic liquid and contacting the organic liquid with a gas such that water is taken up by the gas. The invention, in one embodiment, may be used to dry gel materials whilst maintaining an open porous network therein. In one example, the invention is applied to gel precipitated spheres containing uranium and plutonium. (author)

50

Removing water from gels  

International Nuclear Information System (INIS)

Water is removed from a gel material by contacting the gel material with a gaseous mixture of an organic compound and a gas. The organic compound, the gas and conditions of contacting are selected such that water is extracted from the gel material and passes into the gaseous mixture. In examples, the invention is applied to spherical gel precipitated particles prepared from a mixture of thorium and uranium nitrate solutions. (author)

51

The feasibility of using antigens prepared with rough Brucella strains for diagnosis of canine brucellosis / Utilidad de los antígenos preparados con cepas rugosas de Brucella en el diagnóstico de brucelosis canina  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish Las técnicas más usadas en el diagnóstico de brucelosis canina son la inmunodifusión en gel de agar (AGID), la microaglutinación en portaobjetos (RSAT) y el ELISA indirecto ya que el diagnóstico clínico es poco sensible y el bacteriológico no excluye la enfermedad. Como Brucella canis comparte compo [...] nentes antigénicos con Brucella ovis y Brucella abortus RB51, estas cepas podrían ser usadas indistintamente como antígenos. En este trabajo presentamos datos sobre las pruebas de AGID e IELISA con antígeno B. ovis, RSAT e IELISA con antígeno B. canis e IELISA con antígeno B. abortus RB51. Los puntos de corte ajustados con la curva ROC fueron (%P) 23 para IELISA-B. ovis y (%P) 24 para IELISA-RB51 con 100% de sensibilidad y 98,8% de especificidad. RSAT detectó el 100% de los casos positivos, pero AGID fue menos sensible. Los sueros de los perros tratados con antibióticos tuvieron un %P que correlacionó con la evolución clínica. Los perros presumiblemente infectados con B. suis fueron negativos a todos los ensayos realizados con antígenos de cepas de Brucella rugosas. RSAT es muy sensible como prueba tamiz y los IELISA con antígenos de B. canis, B. ovis y B. abortus RB51 podrían ser usados como confirmatorios ya que han demostrado alta sensibilidad y especificidad. Abstract in english Clinical diagnosis of canine brucellosis is not sensitive enough and a negative blood culture cannot rule out the disease. Indirect methods of serological testing such as agar gel immunodiffusion (AGID), rapid slide agglutination test (RSAT) and indirect enzyme linked immunoassay (IELISA) are prefer [...] red for routine diagnosis. Since Brucella canis shares antigenic components with the Brucella ovis and Brucella abortus RB51 strain, it would seem that either strain could be used as antigen. We present data on AGID and IELISA tests using the B. ovis antigen, RSAT and IELISA using the B. canis antigen and IELISA using the B. abortus RB51 antigen. The cut-off values were adjusted by the ROC analysis; the IELISA-B. ovis cut-off value was 23 (%P) and the IELISA-B. abortus RB51, 24 (%P), with 100% sensitivity and 98.8% specificity. RSAT detected 100% of positive cases, while AGID was less sensitive. The sera from dogs treated with antibiotic showed that %P correlated well with the clinical course. Sera from dogs presumptively infected with B. suis were negative in all tests performed with the rough Brucella strains. RSAT is a very sensitive screening test and IELISA-B. canis, B. ovis and B. abortus RB51 could be used as confirmatory tests, since they show good specificity and sensitivity.

G. I., Escobar; E. J., Boeri; S. M., Ayala; N. E., Lucero.

52

The feasibility of using antigens prepared with rough Brucella strains for diagnosis of canine brucellosis Utilidad de los antígenos preparados con cepas rugosas de Brucella en el diagnóstico de brucelosis canina  

Directory of Open Access Journals (Sweden)

Full Text Available Clinical diagnosis of canine brucellosis is not sensitive enough and a negative blood culture cannot rule out the disease. Indirect methods of serological testing such as agar gel immunodiffusion (AGID, rapid slide agglutination test (RSAT and indirect enzyme linked immunoassay (IELISA are preferred for routine diagnosis. Since Brucella canis shares antigenic components with the Brucella ovis and Brucella abortus RB51 strain, it would seem that either strain could be used as antigen. We present data on AGID and IELISA tests using the B. ovis antigen, RSAT and IELISA using the B. canis antigen and IELISA using the B. abortus RB51 antigen. The cut-off values were adjusted by the ROC analysis; the IELISA-B. ovis cut-off value was 23 (%P and the IELISA-B. abortus RB51, 24 (%P, with 100% sensitivity and 98.8% specificity. RSAT detected 100% of positive cases, while AGID was less sensitive. The sera from dogs treated with antibiotic showed that %P correlated well with the clinical course. Sera from dogs presumptively infected with B. suis were negative in all tests performed with the rough Brucella strains. RSAT is a very sensitive screening test and IELISA-B. canis, B. ovis and B. abortus RB51 could be used as confirmatory tests, since they show good specificity and sensitivity.Las técnicas más usadas en el diagnóstico de brucelosis canina son la inmunodifusión en gel de agar (AGID, la microaglutinación en portaobjetos (RSAT y el ELISA indirecto ya que el diagnóstico clínico es poco sensible y el bacteriológico no excluye la enfermedad. Como Brucella canis comparte componentes antigénicos con Brucella ovis y Brucella abortus RB51, estas cepas podrían ser usadas indistintamente como antígenos. En este trabajo presentamos datos sobre las pruebas de AGID e IELISA con antígeno B. ovis, RSAT e IELISA con antígeno B. canis e IELISA con antígeno B. abortus RB51. Los puntos de corte ajustados con la curva ROC fueron (%P 23 para IELISA-B. ovis y (%P 24 para IELISA-RB51 con 100% de sensibilidad y 98,8% de especificidad. RSAT detectó el 100% de los casos positivos, pero AGID fue menos sensible. Los sueros de los perros tratados con antibióticos tuvieron un %P que correlacionó con la evolución clínica. Los perros presumiblemente infectados con B. suis fueron negativos a todos los ensayos realizados con antígenos de cepas de Brucella rugosas. RSAT es muy sensible como prueba tamiz y los IELISA con antígenos de B. canis, B. ovis y B. abortus RB51 podrían ser usados como confirmatorios ya que han demostrado alta sensibilidad y especificidad.

G. I. Escobar

2010-02-01

53

The feasibility of using antigens prepared with rough Brucella strains for diagnosis of canine brucellosis / Utilidad de los antígenos preparados con cepas rugosas de Brucella en el diagnóstico de brucelosis canina  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish Las técnicas más usadas en el diagnóstico de brucelosis canina son la inmunodifusión en gel de agar (AGID), la microaglutinación en portaobjetos (RSAT) y el ELISA indirecto ya que el diagnóstico clínico es poco sensible y el bacteriológico no excluye la enfermedad. Como Brucella canis comparte compo [...] nentes antigénicos con Brucella ovis y Brucella abortus RB51, estas cepas podrían ser usadas indistintamente como antígenos. En este trabajo presentamos datos sobre las pruebas de AGID e IELISA con antígeno B. ovis, RSAT e IELISA con antígeno B. canis e IELISA con antígeno B. abortus RB51. Los puntos de corte ajustados con la curva ROC fueron (%P) 23 para IELISA-B. ovis y (%P) 24 para IELISA-RB51 con 100% de sensibilidad y 98,8% de especificidad. RSAT detectó el 100% de los casos positivos, pero AGID fue menos sensible. Los sueros de los perros tratados con antibióticos tuvieron un %P que correlacionó con la evolución clínica. Los perros presumiblemente infectados con B. suis fueron negativos a todos los ensayos realizados con antígenos de cepas de Brucella rugosas. RSAT es muy sensible como prueba tamiz y los IELISA con antígenos de B. canis, B. ovis y B. abortus RB51 podrían ser usados como confirmatorios ya que han demostrado alta sensibilidad y especificidad. Abstract in english Clinical diagnosis of canine brucellosis is not sensitive enough and a negative blood culture cannot rule out the disease. Indirect methods of serological testing such as agar gel immunodiffusion (AGID), rapid slide agglutination test (RSAT) and indirect enzyme linked immunoassay (IELISA) are prefer [...] red for routine diagnosis. Since Brucella canis shares antigenic components with the Brucella ovis and Brucella abortus RB51 strain, it would seem that either strain could be used as antigen. We present data on AGID and IELISA tests using the B. ovis antigen, RSAT and IELISA using the B. canis antigen and IELISA using the B. abortus RB51 antigen. The cut-off values were adjusted by the ROC analysis; the IELISA-B. ovis cut-off value was 23 (%P) and the IELISA-B. abortus RB51, 24 (%P), with 100% sensitivity and 98.8% specificity. RSAT detected 100% of positive cases, while AGID was less sensitive. The sera from dogs treated with antibiotic showed that %P correlated well with the clinical course. Sera from dogs presumptively infected with B. suis were negative in all tests performed with the rough Brucella strains. RSAT is a very sensitive screening test and IELISA-B. canis, B. ovis and B. abortus RB51 could be used as confirmatory tests, since they show good specificity and sensitivity.

G. I., Escobar; E. J., Boeri; S. M., Ayala; N. E., Lucero.

2010-02-01

54

CONFORMANCE IMPROVEMENT USING GELS  

Energy Technology Data Exchange (ETDEWEB)

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 flow capacity of fractures (with widths from 1 to 4 mm) during brine and oil flow after placement. Regardless of gel age before placement, very little gel washed out from the fractures during brine or oil flow. However, increased brine or oil flow rate and cyclic injection of oil and water significantly decreased the level of permeability reduction. A particular need exists for gels that can plug large apertures (e.g., wide fractures and vugs). Improved mechanical strength and stability were demonstrated (in 1- to 4-mm-wide fractures) for a gel that contained a combination of high- and low-molecular weight polymers. This gel reduced the flow capacity of 2- and 4-mm-wide fractures by 260,000. In a 1-mm-wide fracture, it withstood 26 psi/ft without allowing any brine flow through the fracture. Cr(III)-acetate-HPAM gels exhibited disproportionate permeability reduction in fractures. The effect was most pronounced when the gel was placed as gelant or partially formed gels. The effect occurred to a modest extent with concentrated gels and with gels that were ''fully formed'' when placed. The effect was not evident in tubes. We explored swelling polymers for plugging fractures. Polymer suspensions were quickly prepared and injected. In concept, the partially dissolved polymer would lodge and swell to plug the fracture. For three types of swelling polymers, behavior was promising. However, additional development is needed before their performance will be superior to that of conventional gels.

Randall S. Seright

2003-09-01

55

Swollen polymers and gels  

International Nuclear Information System (INIS)

This chapter deals with the NMR observation of dynamic fluctuations which occur in polymeric systems observed above or near the glass transition temperature, with emphasis on the restriction brought about over local micro-dynamics by the gelation process: principles of NMR approaches (longitudinal, transverse magnetic relaxation, pseudo-solid spin-echoes); concentrated polymer solutions (segmental motions, solvent diffusion, evidence for a temporary gel-like behaviour, mechanisms near the glass transition); free chains in polymeric gels (dynamical contrast, nature of systems, nature of the spin-system responses, property of superposition, polymeric gel-free volume). 5 fig., 31 ref

56

Agarose Gel Demos  

Science.gov (United States)

This video, presented by WGBH, is a great overview of how to prepare Agarose gel for electrophoresis. The video goes in-depth with the finer points including how to insert the pipette as to not disturb the gel and get the best results. This video would be useful for anyone in biochemistry or molecular biology fields. This video would also be helpful for instructors looking to provide their students with an overview on how to prepare Agarose gel. Educators will also find a background essay, discussion questions, and standards alignment for the material.

2010-09-15

57

Electrophoresis and Gel Analysis  

Science.gov (United States)

In this animation produced by WGBH and Digizyme, Inc., see how molecules of DNA are separated using gel electrophoresis, and how this process enables scientists to compare the molecular variations of two or more DNA samples.

Foundation, Wgbh E.

2011-09-22

58

Crystallization from Gels  

Science.gov (United States)

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 constituents are described. In addition, tables of gel-grown organic and inorganic crystals are provided.

Narayana Kalkura, S.; Natarajan, Subramanian

59

Preparation of chitosan gel  

Science.gov (United States)

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.

Moussaoui, Y.; Mnasri, N.; Elaloui, E.; Ben Salem, R.; Lagerge, S.; de Menorval, L. C.

2012-06-01

60

Preparation of chitosan gel  

Directory of Open Access Journals (Sweden)

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.

Lagerge S.

2012-06-01

 
 
 
 
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Preparation of chitosan gel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Lagerge S.; Ben Salem R.; Elaloui E.; Mnasri N.; Moussaoui Y.; de Menorval L. C.

2012-01-01

62

Prevalência da infecção por lentivírus de pequenos ruminantes em caprinos em Teresina, Piauí Prevalence of small ruminants lentiviruses infection in goats from Teresina, Piauí, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available The prevalence of anti-lentiviruses antibodies of small ruminants was investigated in goat herds in the city of Teresina, PI, Brazil. A seroepidemiological survey was conducted involving 480 animals, apparently healthy, belonging to six rural properties. The diagnostic test was the agar gel immunodiffusion (AGID, using antigens produced from cellular cultures infected with caprine arthritis encephalitis virus (CAEV Cork. Prevalences by gender and age were estimated considering sampling fractions for each farm. A general prevalence of 4.2%, was observerved, being 4.2% for females and 3.6% for males. Prevalences were higher among older goats. Regarding the breed standard, 23.5% were of the Anglo Nubian, 5.9% of the Boer, 35.3% Anglo Nubian x Boer crossbred, and 35.3% of undefined breed. It is concluded that small ruminant lentiviruses are endemic among goat herds of Teresina.

A. Sampaio Júnior

2011-06-01

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

International Nuclear Information System (INIS)

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.)

64

Design of Autonomous Gel Actuators  

Directory of Open Access Journals (Sweden)

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.

Shuji Hashimoto

2011-01-01

65

3D MR gel dosimetry with lung equivalent gel  

International Nuclear Information System (INIS)

The MR gel dosimetry is used to verify complex 3D treatment plans. Till now this method served only for dose evaluation in homogeneous phantoms. On the way to build a heterogeneous anthropomorphic gel phantom, a lung equivalent gel with the density 0.4 g/cm3 was developed. First experiments show a 1.55 times higher dose reponse in the low density gel (LD gel). The comparison of a dose distribution in a gel/LD gel/gel slab phantom with Monte Carlo calculations shows good agreement within 5%. More over the accuray of the measuring device magnetic resonance imager was studied in respect to the now exclusive digital image processing with the software MRD (MR dosimetry). Because of the dimensions of the Fricke gel phantom an artefact correction, based on the data from the unirradiated phantom proved to be essential. (orig.)

66

Transdermal delivery of paeonol using cubic gel and microemulsion gel  

Directory of Open Access Journals (Sweden)

Full Text Available Maofu Luo1,2, Qi Shen1, Jinjin Chen11School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 2Jiangxi University of Traditional Chinese Medicine, Nanchang, People’s Republic of ChinaBackground: The aim of this study was to develop new systems for transdermal delivery of paeonol, in particular microemulsion gel and cubic gel formulations.Methods: Various microemulsion vehicles were prepared using isopropyl myristate as an oil phase, polyoxyethylated castor oil (Cremophor® EL as a surfactant, and polyethylene glycol 400 as a cosurfactant. In the optimum microemulsion gel formulation, carbomer 940 was selected as the gel matrix, and consisted of 1% paeonol, 4% isopropyl myristate, 28% Cremophor EL/polyethylene glycol 400 (1:1, and 67% water. The cubic gel was prepared containing 3% paeonol, 30% water, and 67% glyceryl monooleate.Results: A skin permeability test using excised rat skins indicated that both the cubic gel and microemulsion gel formulations had higher permeability than did the paeonol solution. An in vivo pharmacokinetic study done in rats showed that the relative bioavailability of the cubic gel and microemulsion gel was enhanced by about 1.51-fold and 1.28-fold, respectively, compared with orally administered paeonol suspension.Conclusion: Both the cubic gel and microemulsion gel formulations are promising delivery systems to enhance the skin permeability of paeonol, in particular the cubic gel.Keywords: microemulsion gel, cubic gel, transdermal delivery, paeonol

Chen J

2011-08-01

67

Structure of mineral gels  

International Nuclear Information System (INIS)

Small Angle Neutron Scattering (SANS) measurements have been performed to investigate the nanoscale structure of materials of the systems xTiO2-(1-x)SiO2 and xZrO2-(1-x)SiO2 with x ? 10 mol % at different processing stages. The materials were prepared by sol-gel using the alkoxides method, in strong acidic conditions. Samples were studied as xerogels heat-treated at 120 and 850 deg. C and as wet gels at gel point and after aging. All samples showed identical microstructure at gel point, extended linear chains ?10 nm long. The aged gel has a mass fractal structure with fractal dimension of 1.7 - 1.9. The 120 deg. C heat-treated xerogels show homogeneous oxide regions with mass fractal structure. For the 850 deg. C heat-treated xerogel the oxide regions average size has reduced and it has densified as compared to 120 deg. C heat-treated sample. (author)

68

Active Polymer Gel Actuators  

Directory of Open Access Journals (Sweden)

Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

Shuji Hashimoto

2010-01-01

69

Insoluble hydrophile gels  

International Nuclear Information System (INIS)

A procedure for the preparation of an insoluble hydrofile gel is described. The gel consists of 1-99% polyethylene oxide and 99-1percent starch. The polyethylene and starch are dissolved in water to give a solution with up to 50 weight %, preferably 20 weight%, 0of polyethylene oxide and starch, and the pH is adjusted to between 2 and 11. Cross-linking is achieved by irradiation by, e.g. gamma radiation from Co60 or Cs137, spent fuel elements, X-radiation or electron beams from an accelerator. The radiation energy should be from 0.05 to 20 MeV, and the dose between 0.05 and 10 megarad. The gel may be stabilised by polyethylenimine, using from 0.2 to 3.0 weight%, though up to 50 weight % may be used if desired. (JIW)

70

Gel-silica science  

International Nuclear Information System (INIS)

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)

71

Gel Electrophoresis of Dyes  

Science.gov (United States)

In this experiment related to plant biotechnology, learners discover how to prepare and load an electrophoresis gel. They will then run the gels in an electrophoresis system to separate several dyes that are of different molecular sizes and carry different charges. This technique is fundamental to many of the procedures used in biotechnology. This lesson guide includes background information for the educator, safety precautions, and questions with answers for learners. For safety reasons, adult supervision is recommended. Modifications for use with younger learners are described in a related PDF (see related resource).

Stephens, Janice; Leach, Jan

2011-01-01

72

Swelling of Olympic Gels  

Science.gov (United States)

The swelling equilibrium of Olympic gels, which are composed of entangled cyclic polymers, is studied by Monte Carlo simulations. In contrast to chemically cross-linked polymer networks, we observe that Olympic gels made of chains with a larger degree of polymerization, N, exhibit a smaller equilibrium swelling degree, Q?N-0.28?0-0.72, at the same polymer volume fraction ?0 at network preparation. This observation is explained by a desinterspersion (reorganization with release of nontrapped entanglements) process of overlapping nonconcatenated rings upon swelling.

Lang, M.; Fischer, J.; Werner, M.; Sommer, J.-U.

2014-06-01

73

3D MR gel dosimetry with lung equivalent gel; 3D MR-Gel-Dosimetrie mit lungenaequivalentem Gel  

Energy Technology Data Exchange (ETDEWEB)

The MR gel dosimetry is used to verify complex 3D treatment plans. Till now this method served only for dose evaluation in homogeneous phantoms. On the way to build a heterogeneous anthropomorphic gel phantom, a lung equivalent gel with the density 0.4 g/cm{sup 3} was developed. First experiments show a 1.55 times higher dose reponse in the low density gel (LD gel). The comparison of a dose distribution in a gel/LD gel/gel slab phantom with Monte Carlo calculations shows good agreement within 5%. More over the accuray of the measuring device magnetic resonance imager was studied in respect to the now exclusive digital image processing with the software MRD (MR dosimetry). Because of the dimensions of the Fricke gel phantom an artefact correction, based on the data from the unirradiated phantom proved to be essential. (orig.) [Deutsch] Die MR-Gel-Dosimetrie zur Verifikation komplexer 3D-Bestrahlungsplaene wurde bislang ausschliesslich in homogenen Phantomen durchgefuehrt. Auf dem Wege zum Bau eines inhomogenen Humanoid-Gel-Phantoms wurde ein lungenaequivalentes Gel mit der Dichte 0,4 g/cm{sup 3} entwickelt. Erste Messungen zeigen ein um den Faktor 1,55 hoeheres Ansprechvermoegen in dem low-density-Gel (LD-Gel). Der Vergleich einer gemessen Dosisverteilung in einem Gel/LD-Gel/Gel Schichtphantom als einfaches Thoraxmodell mit Monte-Carlo-Rechnungen zeigt eine gute Uebereinstimmung innerhalb 5%. Ausserdem wurden Untersuchungen zur Messgenauigkeit des Kernspintomographen im Rahmen der nun ausschliesslich digitalen Auswertung mit Hilfe des Programms MRD (MR-Dosimetrie) durchgefuehrt. Es zeigt sich, dass eine Artefaktkorrektur auf der Basis einer Messung des unbestrahlten Phantoms bei grossen Fricke-Gel-Phantomen notwendig ist. (orig.)

Scherer, J.; Solleder, M.; Schiessl, I.; Bogner, L.; Herbst, M. [Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie, Regensburg Univ. (Germany)

1998-12-31

74

Preparing an Agarose Gel  

Science.gov (United States)

This video from CUNY Kingsborough Community College describes the technique of preparing an Agarose Gel. The video describes the process step by step and would be easy to replicate in a laboratory setting. Running time for the video is 3:10.

Shun Ho, Ivan

2013-06-25

75

Running an Agarose Gel  

Science.gov (United States)

This video from CUNY Kingsborough Community College shows the process of running an agarose gel. The video describes the process step by step and would be easy to replicate in a laboratory setting. Running time for the video is 2:52.

Hinkley, Craig

2013-06-17

76

Transdermal delivery of paeonol using cubic gel and microemulsion gel  

Science.gov (United States)

Background The aim of this study was to develop new systems for transdermal delivery of paeonol, in particular microemulsion gel and cubic gel formulations. Methods Various microemulsion vehicles were prepared using isopropyl myristate as an oil phase, polyoxyethylated castor oil (Cremophor® EL) as a surfactant, and polyethylene glycol 400 as a cosurfactant. In the optimum microemulsion gel formulation, carbomer 940 was selected as the gel matrix, and consisted of 1% paeonol, 4% isopropyl myristate, 28% Cremophor EL/polyethylene glycol 400 (1:1), and 67% water. The cubic gel was prepared containing 3% paeonol, 30% water, and 67% glyceryl monooleate. Results A skin permeability test using excised rat skins indicated that both the cubic gel and microemulsion gel formulations had higher permeability than did the paeonol solution. An in vivo pharmacokinetic study done in rats showed that the relative bioavailability of the cubic gel and microemulsion gel was enhanced by about 1.51-fold and 1.28-fold, respectively, compared with orally administered paeonol suspension. Conclusion Both the cubic gel and microemulsion gel formulations are promising delivery systems to enhance the skin permeability of paeonol, in particular the cubic gel. PMID:21904450

Luo, Maofu; Shen, Qi; Chen, Jinjin

2011-01-01

77

Duration of bluetongue viraemia and serological responses in experimentally infected European breeds of sheep and goats.  

Science.gov (United States)

The duration of viraemia and the serological responses were studied in two breeds of sheep and two breeds of goats, experimentally infected with bluetongue (BT) virus serotype 4. Viraemia, detectable by cell culture and embryonated chicken egg inoculation, lasted from the third to sixth day until the 27th-54th day post infection (p.i.). Significant differences between sheep and goats were not recorded. Lesbos sheep and goats together appeared to have significantly longer viraemias (n = 9, mean 41.3 days) than east-Friesian sheep and Saanen goats (n = 10, mean 30.4 days, p = 0.0039). Serological response was studied by competitive ELISA (c-ELISA) and agar gel immunodiffusion (AGID) tests. The c-ELISA was more sensitive in detecting BT virus antibodies in all animals than the AGID tests. No significant differences were observed between sheep and goats or between breeds. The epidemiological significance of subclinical infection and the extended BT virus viraemias in Lesbos sheep and goats, in relation to the maintenance of the virus and to overwintering is discussed. PMID:10063533

Koumbati, M; Mangana, O; Nomikou, K; Mellor, P S; Papadopoulos, O

1999-02-12

78

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

Science.gov (United States)

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

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

79

Toxoplasmosis, leptospirosis and brucellosis in stray dogs housed at the shelter in Umuarama municipality, Paraná, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Background : Leptospirosis, toxoplasmosis and brucellosis are diseases with worldwide distribution. Among stray dogs, these zoonoses are facilitated by direct contact with other animal species, by the habit of scavenging garbage and hunting in search of food, drinking standing water, smelling othe [...] r animals' urine, licking female genitalia and the sexual act itself. The objective of this study was to detect antibodies anti-Toxoplasma gondii, anti-Leptospira spp., anti-Brucella canis and anti-Brucella abortus in stray dogs housed in shelters at Umuarama city, Paraná, Brazil. In order to detect toxoplasmosis, indirect immunofluorescence assay (IFA) was performed, agglutination microscopic (MAT) test for leptospirosis and agar gel immunodiffusion (AGID) and buffered acidified antigen (BAA) tests for brucellosis. Results : Of the 175 serum samples analyzed, 70.85% were considered positive for toxoplasmosis by IFA, 20% by MAT for leptospirosis and 2.85% by AGID for Brucella canis. Conclusions : The serological results of this study showed that stray dogs housed at the private shelter are potential carriers of these three different zoonoses and contribute to the spread and maintenance of these etiologic agents in the urban area of Umuarama (PR), Brazil.

Márcia Küster de Paula, Dreer; Daniela Dib, Gonçalves; Isabel Cristina da Silva, Caetano; Edson, Gerônimo; Paulo Henrique, Menegas; Danilo, Bergo; Fabiana Maria Ruiz, Lopes-Mori; Aline, Benitez; Julio Cesar de, Freitas; Fernanda, Evers; Italmar Teodorico, Navarro; Lisiane de Almeida, Martins.

2013-09-25

80

MAGIC Gel Dosimetry  

Science.gov (United States)

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.

Mifflin, Rachel; Shahnazi, Kambiz; Jesseph, Rick

2008-10-01

 
 
 
 
81

The Gel Generator option  

International Nuclear Information System (INIS)

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 ?-based), an alternative to the fission 99Mo generator, which ought not be overlooked. The application of low specific activity (n,?) 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)

82

Ocular tolerance of sertaconazole gel.  

Science.gov (United States)

The in vitro and in vivo tolerance of sertaconazole gel, a new topical azole antifungal, was studied. Ketoconazole gel (Panfungol) was used as a reference substance. The methods applied for tolerance assessment were the bovine corneal opacity and permeability test for the in vitro assay and a modified Draize test for the in vivo assay. The results obtained show that both substances can be classified as slightly irritant and with acceptable tolerance. However, unlike ketoconazole gel, sertaconazole gel did not cause a positive lesion index in vivo. Ketoconazole was 5.25 times more irritant in vitro than sertaconazole gel, whose effect was similar to that of saline solution. Consequently, the negligible irritant effect of sertaconazole gel on a type of epithelium that is extremely sensitive, i.e. the cornea, confirms the good tolerance of this new antifungal gel on other structures such as the skin and mucous membranes. PMID:8786760

Romero, A; Grau, M T; Villamayor, F; Zapatero, J; Mayordomo, L; Tortajada, A; Sacristán, A; Ortiz, J A

1996-01-01

83

Duration of passive immunity to small ruminant lentiviruses in lambs  

Directory of Open Access Journals (Sweden)

Full Text Available In order to evaluate the passive immunity against small ruminant lentiviruses (SRLV in lambs, this study was conducted from two experimental groups. The first one (G1 was established by nine lambs subjected to artificial feeding of colostrum of goats positive for SRLV. The second one (G2 was the control group, consisting of ten lambs subjected to suckling of colostrum from their negative mothers. Blood samples were obtained before the first feeding, after 24 hours of birth and at 7, 15, 30, 50, 70, 90 and 120 days of age. The concentrations of total serum protein (TSP, albumin (ALB, globulin (GLOB and immunoglobulin G (IgG were determined and antibodies to SRLV were surveyed from the techniques of agar gel immunodiffusion (AGID, enzyme linked immunosorbent assay (Elisa and immunoblotting (IB. In both groups, the lowest averages of TSP, GLOB and IgG were observed at birth and the highest averages were observed at 24 hours of life, due to absorption of colostral immunoglobulins. For G1, transfer of immunity could also be detected by immunodiagnostic tests. At birth, the animals were seronegative. After 24 hours, all animals were positive in three serological tests. Negative results began to be observed after 15 days of age by the AGID test. As for Elisa testing, all animals remained reagent until 50 days old. Only IB was able to detect anti-SRLV at 70 days. Regarding G2, all animals tested negative in AGID and IB, from birth until 120 days of age. However, false-positive results were observed until day 15 in Elisa, due to nonspecific reactions. These data are consistent with the sensitivity and specificity of serological tests and show that starting at 90 days of age, colostral antibodies to SRLV are no longer detected in the serum of lambs.

Thiago Sampaio de Souza

2014-02-01

84

Detecção de Erwinia psidii via enriquecimento em extrato de folhas de goiabeira e imunodifusão radial dupla Detection of Erwinia psidii through enrichment in guava leaf extract and double radial immunodiffusion  

Directory of Open Access Journals (Sweden)

Full Text Available Uma das principais doenças que afetam a produção de goiaba no Brasil é a seca-dos-ponteiros, causada pela bactéria Erwinia psidii, cuja disseminação é favorecida por mudas contaminadas. O desenvolvimento de métodos diagnósticos mais eficazes poderia reduzir a disseminação da bactéria no país. Considerando a necessidade de se disponibilizar um método eficiente e simples para a detecção de E. psidii em material de propagação, foi objetivo desse trabalho produzir antissoros policlonais específicos contra a bactéria e desenvolver um método de detecção utilizando o enriquecimento da população bacteriana em extrato de folhas de goiabeira seguido de imunodifusão radial dupla. Um antissoro foi produzido contra a estirpe tipo da bactéria IBSBF 435 (ICMP 8426, NCPPB 3555, avaliado quanto à eficiência e especificidade e utilizado na determinação dos limiares de detecção da mesma. O antissoro As15-1 reagiu positivamente com todos as estirpes testadas de E. psidii, não reagindo com estirpes de outros gêneros e espécies de bactérias fitopatogênicas e apresentou reação cruzada com dois isolados não patogênicos da flora da goiabeira. O crescimento da população bacteriana no extrato de folhas foi observado após 12 h de incubação a partir de populações iniciais de 10³, 10(5 e 10(7 ufc/mL, até 60 h. A partir de 12 h, já foi possível detectar E. psidii por enriquecimento e imunodifusão radial nas amostras com populações iniciais de 10(7 ufc/mL e a partir de 36 h, detectou-se a bactéria mesmo em amostras com populações iniciais de 10³ ufc/mL. Considerando a possibilidade de falsos positivos, é recomendável associar outros métodos diagnósticos ao método aqui proposto.One of the most important diseases affecting guava production in Brazil is bacterial blight, caused by the bacterium Erwinia psidii. Pathogen dissemination often occurs through contaminated propagating plant material. The development of more effective diagnostic methods may reduce pathogen dissemination in the country. Considering the need for a reliable and simple method for detecting the pathogen in plant material, the objectives of this study were to produce E. psdii-specific polyclonal antibodies and to develop a detection method using bacterial population enrichment on guava leaf extracts followed by double radial immunodiffusion. The antiserum was produced against the E. psidii type strain IBSBF 435 (ICMP 8426, NCPPB 3555 and its efficiency, specificity and sensitivity threshold were determined. The antiserum As15-1 was tested with strains of several plant-pathogenic bacteria and reacted positively with all strains of E. psidii, although cross reactions were detected with two non-pathogenic isolates from guava flora. Bacterial multiplication on leaf extracts was observed 12 h after incubation from initial populations of 10³, 10(5 and 10(7 ufc/mL, up to 60 h. After 12 h it was already possible to detect E. psidii in samples with starting populations of 10(7 cfu/mL. After 36 h, the enrichment technique allowed the detection of E. psidii using double radial immunodiffusion in samples with populations as low as 10³ cfu/mL. Considering the possibility of false positives it is desirable to associate other diagnostic methods with the method proposed in this study.

Ana Cristina O. Teixeira

2008-06-01

85

Detecção de Erwinia psidii via enriquecimento em extrato de folhas de goiabeira e imunodifusão radial dupla / Detection of Erwinia psidii through enrichment in guava leaf extract and double radial immunodiffusion  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Uma das principais doenças que afetam a produção de goiaba no Brasil é a seca-dos-ponteiros, causada pela bactéria Erwinia psidii, cuja disseminação é favorecida por mudas contaminadas. O desenvolvimento de métodos diagnósticos mais eficazes poderia reduzir a disseminação da bactéria no país. Consid [...] erando a necessidade de se disponibilizar um método eficiente e simples para a detecção de E. psidii em material de propagação, foi objetivo desse trabalho produzir antissoros policlonais específicos contra a bactéria e desenvolver um método de detecção utilizando o enriquecimento da população bacteriana em extrato de folhas de goiabeira seguido de imunodifusão radial dupla. Um antissoro foi produzido contra a estirpe tipo da bactéria IBSBF 435 (ICMP 8426, NCPPB 3555), avaliado quanto à eficiência e especificidade e utilizado na determinação dos limiares de detecção da mesma. O antissoro As15-1 reagiu positivamente com todos as estirpes testadas de E. psidii, não reagindo com estirpes de outros gêneros e espécies de bactérias fitopatogênicas e apresentou reação cruzada com dois isolados não patogênicos da flora da goiabeira. O crescimento da população bacteriana no extrato de folhas foi observado após 12 h de incubação a partir de populações iniciais de 10³, 10(5) e 10(7) ufc/mL, até 60 h. A partir de 12 h, já foi possível detectar E. psidii por enriquecimento e imunodifusão radial nas amostras com populações iniciais de 10(7) ufc/mL e a partir de 36 h, detectou-se a bactéria mesmo em amostras com populações iniciais de 10³ ufc/mL. Considerando a possibilidade de falsos positivos, é recomendável associar outros métodos diagnósticos ao método aqui proposto. Abstract in english One of the most important diseases affecting guava production in Brazil is bacterial blight, caused by the bacterium Erwinia psidii. Pathogen dissemination often occurs through contaminated propagating plant material. The development of more effective diagnostic methods may reduce pathogen dissemina [...] tion in the country. Considering the need for a reliable and simple method for detecting the pathogen in plant material, the objectives of this study were to produce E. psdii-specific polyclonal antibodies and to develop a detection method using bacterial population enrichment on guava leaf extracts followed by double radial immunodiffusion. The antiserum was produced against the E. psidii type strain IBSBF 435 (ICMP 8426, NCPPB 3555) and its efficiency, specificity and sensitivity threshold were determined. The antiserum As15-1 was tested with strains of several plant-pathogenic bacteria and reacted positively with all strains of E. psidii, although cross reactions were detected with two non-pathogenic isolates from guava flora. Bacterial multiplication on leaf extracts was observed 12 h after incubation from initial populations of 10³, 10(5) and 10(7) ufc/mL, up to 60 h. After 12 h it was already possible to detect E. psidii in samples with starting populations of 10(7) cfu/mL. After 36 h, the enrichment technique allowed the detection of E. psidii using double radial immunodiffusion in samples with populations as low as 10³ cfu/mL. Considering the possibility of false positives it is desirable to associate other diagnostic methods with the method proposed in this study.

Ana Cristina O., Teixeira; Marisa A.S.V., Ferreira; Abi S.A., Marques.

86

Hydrodynamics of active permeating gels  

Energy Technology Data Exchange (ETDEWEB)

We develop a hydrodynamic theory of active permeating gels with viscoelasticity in which a polymer network is embedded in a background fluid. This situation is motivated by active processes in the cell cytoskeleton in which motor molecules generate elastic stresses in the network, which can drive permeation flows of the cytosol. Our approach differs from earlier ones by considering the elastic strain in the polymer network as a slowly relaxing dynamical variable. We first present the general ideas for the case of a passive, isotropic gel and then extend this description to a polar, active gel. We discuss two specific cases to illustrate the role of permeation in active gels: self-propulsion of a thin slab of gel relative to a substrate driven by filament polymerization and depolymerization; and non-equilibrium deswelling of a gel driven by molecular motors.

Callan-Jones, A C [Laboratoire Charles Coulomb, UMR 5521 CNRS-UM2, Universite Montpellier II, 34095 Montpellier Cedex 5 (France); Juelicher, F, E-mail: andrew.callan-jones@univ-montp2.fr [Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzerstrasse 38, 01187 Dresden (Germany)

2011-09-15

87

High transparent shape memory gel  

Science.gov (United States)

Gels are a new material having three-dimensional network structures of macromolecules. They possess excellent properties as swellability, high permeability and biocompatibility, and have been applied in various fields of daily life, food, medicine, architecture, and chemistry. In this study, we tried to prepare new multi-functional and high-strength gels by using Meso-Decoration (Meso-Deco), one new method of structure design at intermediate mesoscale. High-performance rigid-rod aromatic polymorphic crystals, and the functional groups of thermoreversible Diels-Alder reaction were introduced into soft gels as crosslinkable pendent chains. The functionalization and strengthening of gels can be realized by meso-decorating the gels' structure using high-performance polymorphic crystals and thermoreversible pendent chains. New gels with good mechanical properties, novel optical properties and thermal properties are expected to be developed.

Gong, Jin; Arai, Masanori; Kabir, M. H.; Makino, Masato; Furukawa, Hidemitsu

2014-03-01

88

Electrically controlled polymeric gel actuators  

Science.gov (United States)

Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

Adolf, Douglas B. (Albuquerque, NM); Shahinpoor, Mohsen (Albuquerque, NM); Segalman, Daniel J. (Albuquerque, NM); Witkowski, Walter R. (Albuquerque, NM)

1993-01-01

89

Thoria sol-gel processes  

International Nuclear Information System (INIS)

Alternate fuel fabrication techniques are being developed at WNRE as part of the thorium fuel cycle program. The sol-gel techniques are attractive and this report assembles and summarizes information relating to thoria sol-gel fuels. Some background information on the behaviour and advantages of sol-gel fuel forms is presented, followed by a review of relevant colloid chemistry and an explanation of the fundamental steps of sol-gel processes. Finally, several variants to the basic process are reviewed and evaluated. (author)

90

Radiotherapy Gel Dosimetry: Development and Application of Normoxic Polymer Gels  

Energy Technology Data Exchange (ETDEWEB)

In many radiotherapy applications, true three-dimensional dosimetry with good spatial resolution that can be achieved in a single measurement would be of great value. Polymer gel dosimetry fulfils many of the demands on such a system. In this study, methods to facilitate the implementation of gel dosimetry have been investigated. A new type of polymer gel, for which the response to absorbed dose is not negatively affected even if manufacturing is undertaken at normal levels of oxygen, called normoxic gel, was studied. The concept of percentage dose resolution was introduced to enable optimization of gel compositions for use in relative dosimetry applications. This concept was applied to demonstrate the effects of varying the gel composition on gel performance. Comparison between data obtained using magnetic resonance imaging and FT-Raman spectroscopy indicated that not all water protons attached to the polymer are accessible for exchange of magnetization with other proton groups. Dose response characteristics were investigated for a polymer gel containing the antioxidant tetrakis(hydroxymethyl)phosphonium. The transversal relaxation time (R2) versus dose response increased with increasing amounts of monomer, while no systematic dependence on antioxidant concentration was observed. The investigated normoxic gel exhibited a dependence on temperature during irradiation, leading to differences in absolute R2 as well as deviations in relative depth dose curves. It was suggested that the deviation in R2 can be attributed to structural differences in the polymer matrix, caused by varying polymerisation temperature. A linear relationship between absorbed dose and optical attenuation coefficient was observed, which demonstrates the potential for evaluation using light transmission measurements. Low-density gel was manufactured by mixing normal density normoxic gel with Styrofoam spheres. A linear correlation between R2 and dose was observed for doses up to 15 Gy. Possible dose response dependence on linear energy transfer (LET) was investigated using proton beam absorbed dose measurements. An increased LET with depth was closely followed by a decrease in relative detector sensitivity, indicating that the response of this type of gel detector is dependent on LET. No significant effects were observed for LET < 2.5 keV/mm, indicating that the detector response would not be altered in the range of LET values expected for photons or electrons in a clinical range of energies. The feasibility of using normoxic gel for intensity-modulated radiation therapy verification was investigated. Good agreement between treatment planning system calculations and measured data was obtained. For the planning target volume, the calculated and the measured mean relative dose was 96.8{+-}2.5% ({+-}1 SD) and 98.6{+-}2.2%, respectively. The results indicated great potential for intensity-modulated radiation therapy verification using normoxic polymer gel.

Gustavsson, Helen

2004-04-01

91

Inquérito sorológico e fatores de risco para a brucelose por Brucella canis em cães do município de Santana de Parnaíba, Estado de São Paulo / Serological survey and risk factors for brucellosis due to Brucella canis in dogs of the Santana de Parnaíba municipality, State of São Paulo  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foi investigada a prevalência da brucelose causada por Brucella canis em cães do município de Santana de Parnaíba, SP, Brasil, e realizado um estudo de possíveis fatores de risco associados à soropositividade para B. canis. Foram examinadas 410 amostras de soro sanguíneo de cães colhidas durante a c [...] ampanha de vacinação anti-rábica animal, realizada em agosto de 1999. A imunodifusão em gel de ágar (IDGA), utilizando antígeno de lipopolissacarídeos e proteínas de Brucella ovis, amostra Reo 198, foi empregada em soros normais como teste de triagem, e, para a confirmação, a mesma técnica foi aplicada em soros tratados pelo 2-mercaptoetanol (IDGA-ME). A reação de fixação de complemento (CFT), utilizando antígeno de B. ovis, amostra 63/290, também foi utilizada como prova confirmatória. A determinação da prevalência considerou como positivos os animais que reagiram positivamente nos dois testes confirmatórios (IDGA-ME e CFT). A prevalência da B. canis foi de 2,2% (I.C. 95% = 1,01-4,13%). A análise estatística mostrou que os cães com acesso irrestrito à rua o dia todo (manejo do tipo solto) estiveram mais expostos ao risco da infecção por B. canis, com um valor de odds ratio de 8,73 (I.C. 95% = 1,48-51,55) e p=0,04. Abstract in english The prevalence of brucellosis due to Brucella canis was investigated in dogs of the Santana de Parnaíba county, State of São Paulo, southeastern Brazil, and the risk factors for infection were analyzed. For this purpose, 410 blood samples were collected from dogs during the rabies vaccination campai [...] gn, in August 1999. The agar gel immunodiffusion test (AGID), using lipopolysaccharides and protein antigens from Brucella ovis, strain Reo 198, was applied first as a screening test on normal sera, and secondly, for confirmation. The same AGID test was applied to sera treated previously with 2-mercaptoethanol (ME-AGID). The complement fixation test (CFT), using B. ovis antigen, strain 63/290, was applied also as a confirmatory test. For the prevalence analysis, animals presenting positive results in both ME-AGID and CFT were considered positive. The prevalence of brucellosis due to B. canis was 2.2% (95% C.I.=1.01-4.13%). Dogs that were allowed by their owners to stay free outside their home had a higher risk for contracting B. canis infection, with an odds ratio value of 8.73 (95% C.I.=1.48-51.55) and p=0.04.

Sérgio S., Azevedo; Sílvio A., Vasconcellos; Clebert J., Alves; Lara B., Keid; Lília M.P. S., Grasso; Roberta, Mascolli; Sônia R., Pinheiro.

2003-12-01

92

Phase behaviors of agarose gel  

Directory of Open Access Journals (Sweden)

Full Text Available We present evidence for the existence of phase separation in the gel state of agarose having the mixture of water and methanol as the gel solvent. Firstly, the sol-gel transition line and the cloud point line are determined independently as a function of the concentration of agarose as well as the concentration of methanol in the mixed solvent by the quasi-equilibrium cooling of the solutions. Then the spinodal line is determined by quenching the solutions below the sol-gel transition line. We find that the spinodal line appears below the cloud point line and both lines are entirely buried below the sol-gel transition line in the aqueous agarose system. The concentration fluctuations are, therefore, frozen into the polymer network of agarose gel that promotes the opacity of the resultant gel. The structure of agarose gel is observed by the confocal laser scanning microscope (CLSM imaging technique that reveals that the density fluctuations are grown up to micrometer scale in space. The phase separation boundary is found to shift to the higher temperature region than the sol-gel transition line when the concentration of methanol in the mixed solvent is increased. The results indicate that the position of the phase separation boundary in relative to the sol-gel transition line varies with the quality of solvent. These results are in agreement with the theory of the sol-gel transition in which both the divergence of the connectivity and the thermodynamic instability are taken into account.

Takaharu Morita

2013-04-01

93

Difference gel electrophoresis.  

Science.gov (United States)

DIGE is a protein labelling and separation technique allowing quantitative proteomics of two or more samples by optical fluorescence detection of differentially labelled proteins that are electrophoretically separated on the same gel. DIGE is an alternative to quantitation by MS-based methodologies and can circumvent their analytical limitations in areas such as intact protein analysis, (linear) detection over a wide range of protein abundances and, theoretically, applications where extreme sensitivity is needed. Thus, in quantitative proteomics DIGE is usually complementary to MS-based quantitation and has some distinct advantages. This review describes the basics of DIGE and its unique properties and compares it to MS-based methods in quantitative protein expression analysis. PMID:19003860

Timms, John F; Cramer, Rainer

2008-12-01

94

Vanadium pentoxide gels  

International Nuclear Information System (INIS)

This paper reports on cryogenic transmission electron Microscopy (cry-TEM) and rheological characterization conducted in order to understand structural development of vanadium pentoxide gels during processing. Sols were prepared by ion exchange from sodium metavanadate solutions. Cryo-TEM revealed that fine threads about 1.5nm wide initially form and grow into ribbons approximately 25nm wide and at least 1000nm long. The threads appear to self assembly into the ribbons. During this structural development, the dynamic viscosity increased. Upon steady shearing of the sols, the system exhibited thixotropy, i.e. the viscosity decreased with time under constant shear stress and subsequently rheopexy, the viscosity increased with time. Comparison of the structure before and after shearing indicated that during the rheological experiments aggregation of small particles or fragments was occurring

95

Radiotherapy gel dosimetry  

International Nuclear Information System (INIS)

In radiotherapy, the primary objective is to deliver a prescribed dose of radiation to a tumour or lesion within a patient while minimising the dose delivered to the surrounding healthy tissue. Traditional radiotherapy treatments usually involve simple external or internal irradiations of a tumour. External irradiations are normally achieved in the clinic with photon or electron beams produced by high energy linear accelerators. The photon or electron beams are collimated into regular shapes as they emerge from the treatment head of the unit which is supported by a gantry that can be rotated isocentrically to any position. A discrete number of photon or electron beams with different angles of incidence that intersect at the iso-centre are used to produce a region of high dose around the tumour volume (positioned at the iso-centre). Internal irradiations are normally achieved in the clinic by implanting radioactive sources in and around the tumour or lesion. Such irradiations are characterised by very high doses local to the tumour. Radioactive sources are also used to prevent post-angioplasty restenosis by inserting sources into arteries. Usually when treating a tumour, a compromise is made between tumour control and complications arising from normal tissue damage. One measure of this compromise, the therapeutic ratio, is defined as the radiation dose producing complications in 50% of patients divided by the dose providing tumour control in 50% of the patients. The therapeutic ratio depends on the radiobiological characteristics of the cancerous tissue and surrounding healthy tissues and on the radiation dose distribution achieved by the radiotherapy treatment. It is generally believed that the therapeutic ratio can be minimised by optimising the conformation of the radiation dose distribution to the target volume. This is difficult with traditional radiotherapy techniques since they do not produce dose distributions that adequately cover tumour volumes of complex 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 be either through direct absorption of ionising radiation or via intermediate water free rad

96

Nanocrystal/sol-gel nanocomposites  

Science.gov (United States)

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

Petruska, Melissa A. (Los Alamos, NM); Klimov, Victor L. (Los Alamos, NM)

2012-06-12

97

Electrochemical Light-Emitting Gel  

Directory of Open Access Journals (Sweden)

Full Text Available Light-emitting gel, a gel state electroluminescence material, is reported. It is composed of a ruthenium complex as the emitter, an ionic liquid as the electrolyte, and oxide nanoparticles as the gelation filler. Emitted light was produced via electrogenerated chemiluminescence. The light-emitting gel operated at low voltage when an alternating current was passed through it, regardless of its structure, which is quite thick. The luminescence property of the gel is strongly affected by nanoparticle materials. TiO2 nanoparticles were a better gelation filler than silica or ZnO was, with respect to luminescence stability, thus indicating a catalytic effect. It is demonstrated that the light-emitting gel device, with quite a simple fabrication process, flashes with the application of voltage.

Nobuyuki Itoh

2010-06-01

98

21 CFR 520.1452 - Moxidectin gel.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Moxidectin gel. 520.1452 Section 520.1452 Food and...NEW ANIMAL DRUGS § 520.1452 Moxidectin gel. (a) Specifications . Each milliliter of gel contains 20 milligrams (2 percent)...

2010-04-01

99

Polysaccharide strong and weak gels.  

Science.gov (United States)

Small deformation oscillatory shear measurements have enabled a distinction to be made between so-called "strong" and "weak" gels, in particular those formed from biologically significant polysaccharides. At small enough strains, both systems give essentially the same mechanical spectrum, with G' > G", and with both moduli largely independent of frequency. However, the deformation dependence of the two classes of materials is very different. Strong gels are essentially strain independent (linearly viscoelastic) for strains of greater than about 0.25, whereas weak gels show such a response only for strains of less than about 0.05. At large deformations strong gels will rupture and fail, and will never "heal" without melting and resetting. Conversely, weak gels will recover and can flow without fracture, giving a power law response, with an exponent approaching -1, so-called "yield stress" behavior. The rheological properties of a strong gel, agarose, derived from the Rhodophyceae (marine algae) and a weak gel xanthan, an exocellular slime exuded by bacteria of the genus Xanthomonas, are measured in vitro, and related to in vivo requirements. PMID:8286724

Ross-Murphy, S B; Shatwell, K P

1993-01-01

100

Characterization of rehydrated gelatin gels.  

Science.gov (United States)

Five percent glutaraldehyde cross-linked gels have shown excellent blood compatibility as coatings for cardiac prostheses. A method was developed for producing thin dehydrated coatings using a proprietary dehydration procedure and ethylene oxide (EO) sterilization. The swollen surfaces of rehydrates versus wet (original) gels were compared. Within 30 min of saline rehydration, dry 30-50-microns films on textured surfaces became smooth, uniform, and comparable to original gelatin gels. Mechanical test results after rehydration showed values for strain remain unchanged (39.3 + 10.0 to 40.0 + 7.8%), but stress increased (2.79 + 1.21 to 4.22 + 1.60 dyne/cm2; p less than 0.01). The contact angle data reported gamma C values of 26.1 and 30.4 dyne/cm for original and rehydrated gels. Using a coulometric titrimeter, the measured water content of original gels was reduced from 85 to 3.4% after drying. Dried and saline rehydrated gels had a 73.2% moisture content. Gels shrank 8.8% of their original length after rehydration; however, the thickness of all pump coatings remained stable. Two-hour incubations with bovine platelet rich plasma showed no differences in platelet reactivity or morphology when compared to original gels. Light microscopy and scanning electron microscopy (SEM) showed no evidence of gel cracking or surface defects after pump endurance testing for 3 and 5 weeks. The process of dehydration eliminates the wet storage and sterility problems of such hydrogels and provides a stable film coating for a variety of blood-contacting substrates. PMID:1998488

Emoto, H; Kambic, H; Chen, J F; Nosé, Y

1991-02-01

 
 
 
 
101

Denaturing gradient gel electrophoresis  

International Nuclear Information System (INIS)

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

102

Adhesive, elastomeric gel impregnating composition  

Science.gov (United States)

An improved capacitor roll with alternating film and foil layers is impregnated with an adhesive, elastomeric gel composition. The gel composition is a blend of a plasticizer, a polyol, a maleic anhydride that reacts with the polyol to form a polyester, and a catalyst for the reaction. The impregnant composition is introduced to the film and foil layers while still in a liquid form and then pressure is applied to aid with impregnation. The impregnant composition is cured to form the adhesive, elastomeric gel. Pressure is maintained during curing.

Shaw, David Glenn (Tucson, AZ); Pollard, John Randolph (Tucson, AZ); Brooks, Robert Aubrey (Tijeras, NM)

2002-01-01

103

Introduction to Agarose Gel Electrophoresis  

Science.gov (United States)

In this module, developed as part of Cornell's Learning Initiative in Medicine and Bioengineering (CLIMB), students are introduced to the concepts of gel electrophoresis without requiring all the equipment needed to run a full gel electrophoresis experiment. The goal is to have students understand how gels are made for DNA separation and how altering the composition can affect the experimental parameters. This module contains a teacher's guide, classroom activity, and suggestions for extended activities. This lab is a precursor to Cornellâs Institute for Biology Teachers labâs entitled DNA Profiling â Paternity Testing, which is linked within the teacher's guide. CLIMB is part of the NSF GK-12 program.

Bioengineering, Climb: C.

104

by sol-gel method  

Directory of Open Access Journals (Sweden)

Full Text Available Se ha usado la inmersión de substratos en un sol-gel hecho de un composito para preparar películas delgadas de TiO2 ya sean lisas o rugosas sobre fibra de vidrio. La deposición de películas se hizo desde una solución de isopropóxido de titanio (IV como precursor del sol-gel y bromuro de cetil-trimetil-amonio como surfactante. Las muestras fueron caracterizadas usando las técnicas de espectroscopia Raman y Uv-visible, así como la microscopia electrónica de barrido y de fuerza atómica. En casos especiales, la deposición de película consiste en un gel precursor de titanio que encapsula micelas de surfactante. La película de gel es convertida a la fase anatasa por calcinación a 500 °C, las películas lisas de TiO2 pueden tener propiedades ópticas y protectoras y la rugosidad de las películas de TiO2 puede aumentar su inherente actividad foto catalítica.

Jorge Medina-Valtierra

2006-01-01

105

Self polymerising ionic liquid gel.  

Science.gov (United States)

A novel self-polymerised ionic liquid (IL) gel was prepared at room temperature (RT), without light or heat or addition of initiator, using a new IL, choline formate (CF), and 2-hydroxyethyl methacrylate (HEMA). PMID:19462080

Winther-Jensen, Orawan; Vijayaraghavan, R; Sun, Jiazeng; Winther-Jensen, Bjorn; MacFarlane, Douglas R

2009-06-01

106

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A prova de Imunodifusão Radial (IDR) é um método in vitro conveniente para determinar a concentração de antígenos no produto final como um todo, de vacinas anti-rábicas para uso veterinário. Os reativos padrões candidatos para uso na prova IDR, proposta para o controle de processo de vacinas de cult [...] ivo celular, elaboradas na América Latina e Caribe, foram produzidos e padronizados no Instituto Panamericano de Proteção de Alimentos e Zoonoses (INPPAZ). A validação dos padrões e o controle de qualidade de 28 lotes de vacinas anti-rábicas, de diferentes procedências, foram realizados na Faculdade de Ciências Veterinárias da Universidade de La Plata, Argentina (UNLP). Todas as vacinas foram elaboradas com virus rábico cepa Pasteur (PV) em células BHK e sua atividade foi determinada através de provas in vivo (NIH) e in vitro (IDR). Os resultados dos reativos, candidatos para as provas de padronização, demonstraram estabilidade, sensibilidade e reprodutibilidade. Por análise de variância e de regressão foi estimada a potência relativa de 1.2 entre as vacinas problemas e a vacina de referência. Os resultados deste estudo de validação indicam que o INPPAZ, está em condições de elaborar e distribuir os reativos padrões acima mencionados e apoiar a adoção da técnica de IDR (sensível, rápida, econômica) pelos laboratórios de produção de vacinas anti-rábicas da América Latina e Caribe. Abstract in english 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 standa [...] rdization 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.

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

2000-06-01

107

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

Science.gov (United States)

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-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels with respect to pH changes was probed by quartz crystal microbalance with dissipation (QCM-D) and TIRR. Highly cross-linked gels show a small and fully reversible behavior when the solution pH is switched between pH 2.7 and 5.7. In contrast, low cross-linked gels are more responsive to pH changes, but the response is fully reversible only after the first exposure to the acidic solution, once an internal restructuring of the gel has taken place. Two distinct pKa's for both chitosan and poly(acrylic acid), were determined for the cross-linked structure using TIRR. They are associated with populations of chargeable groups displaying either a bulk like dissociation behavior or forming ionic complexes inside the hydrogel film. PMID:25006685

Liu, Chao; Thormann, Esben; Claesson, Per M; Tyrode, Eric

2014-07-29

108

Alternative imaging modalities for polymer gel dosimetry  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2010-11-01

109

Thixotropic gel for vadose zone remediation  

Science.gov (United States)

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.

Rhia, Brian D. (Augusta, GA)

2011-03-01

110

Rheology and structure of milk protein gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 that both the fraction whey protein aggregated with the casein particles and whey protein aggregates dispersed in the continuous phase have a large impact on the structural and mechanical properties ...

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

2004-01-01

111

Capillary fracture of soft gels  

CERN Document Server

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 propagate with a universal power law $L\\propto t^{3/4}$. 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 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 impo...

Bostwick, Joshua B

2013-01-01

112

Copolymers For Capillary Gel Electrophoresis  

Science.gov (United States)

This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

Liu, Changsheng (State College, PA); Li, Qingbo (State College, PA)

2005-08-09

113

Statistical physics of polymer gels  

Science.gov (United States)

This work presents a comprehensive analysis of the statistical mechanics of randomly cross-linked polymer gels, starting from a microscopic model of a network made of instantaneously cross-linked Gaussian chains with excluded volume, and ending with the derivation of explicit expressions for the thermodynamic functions and for the density correlation functions which can be tested by experiments. Using replica field theory we calculate the mean field density in replica space and show that this solution contains statistical information about the behavior of individual chains in the network. The average monomer positions change affinely with macroscopic deformation and fluctuations about these positions are limited to length scales of the order of the mesh size. We prove that a given gel has a unique state of microscopic equilibrium which depends on the temperature, the solvent, the average monomer density and the imposed deformation. This state is characterized by the set of the average positions of all the monomers or, equivalently, by a unique inhomogeneous monomer density profile. Gels are thus the only known example of equilibrium solids with no long-range order. We calculate the RPA density correlation functions that describe the statistical properties of small deviations from the average density, due to both static spatial heterogeneities (which characterize the inhomogeneous equilibrium state) and thermal fluctuations (about this equilibrium). We explain how the deformation-induced anisotropy of the inhomogeneous equilibrium density profile is revealed by small angle neutron scattering and light scattering experiments, through the observation of the butterfly effect. We show that all the statistical information about the structure of polymer networks is contained in two parameters whose values are determined by the conditions of synthesis: the density of cross-links and the heterogeneity parameter. We find that the structure of instantaneously cross-linked gels becomes increasingly inhomogeneous with the approach to the cross-link saturation threshold at which the heterogeneity parameter diverges. Analytical expressions for the correlators of deformed gels are derived in both the long wavelength and the short wavelength limits and an exact expression for the total static structure factor, valid for arbitrary wavelengths, is obtained for gels in the state of preparation. We adapt the RPA results to gels permeated by free labelled chains and to gels in good solvents (in the latter case, excluded volume effects are taken into account exactly) and make predictions which can be directly tested by scattering and thermodynamic experiments. Finally, we discuss the limitations and the possible extensions of our work.

Panyukov, Sergei; Rabin, Yitzhak

1996-05-01

114

29 CFR 1910.1027 - Cadmium.  

Science.gov (United States)

...metallothionein-cadmium complex that represents the primary transport mechanism for cadmium delivery to the...earliest tests used to measure B2MU was the radial immunodiffusion technique...methods (including gel electrophoresis, radial immunodiffusion, and...

2010-07-01

115

Screening effect on nanostructure of charged gel  

Science.gov (United States)

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.

Sugiyama, Masaaki; Annaka, Masahiko; Hino, Masahiro; Fukunaga, Toshiharu; E. Vigild, Martin; Hara, Kazuhiro

2004-07-01

116

Screening effect on nanostructure of charged gel  

Energy Technology Data Exchange (ETDEWEB)

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.

Sugiyama, Masaaki; Annaka, Masahiko; Hino, Masahiro; Fukunaga, Toshiharu; Vigild, Martin E.; Hara, Kazuhiro

2004-07-15

117

Gel Electrophoresis Lab: Paternity Case  

Science.gov (United States)

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators provides instructions for conducting a gel electrophoresis lab. Students will try to solve a paternity case with this activity by obtaining a DNA fingerprint from each potential father, the mother and the child. This activity may be downloaded in PDF file format. A data collection sheet and student questions are also included.

2013-07-05

118

Gel Electrophoresis Lab: DNA Fingerprinting  

Science.gov (United States)

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators introduces the methods of RFLP analysis, or DNA fingerprinting, by using gel electrophoresis. Students will learn the role of restriction enzymes in DNA fingerprinting. Required materials, procedure and instructions are provided. This lesson plan may be downloaded in Microsoft Word document file format.

Ehlers, Megan

2012-10-24

119

Study of Fricke gel dosimeter response for different gel quality  

Science.gov (United States)

The Fricke xylenol gel (FXG) dosimeter has been studied for application in radiotherapy because it is capable of to measure the spatial distribution of radiation doses. The dosimetry is based on the oxidation of ferrous (Fe2+) to ferric (Fe3+) ions radiation induced, related to the radiation dose. The gel material usually employed is the 300 Bloom gelatin, which is imported and very expensive in Brazil. Aiming to analyze the viability of to use a locally produced and low cost gel material, in this work the spectrophotometric responses of FXG solutions prepared using 270 Bloom gelatin commercially available and 300 Bloom gelatin imported were compared. The absorption spectra of solutions prepared with 5% by weight 270 and 300 Bloom gelatins non-irradiated and irradiated with 60Co gamma radiation in the dose range between 0.5 and 100 Gy were analysed, the dose-response curves were evaluated and the useful dose range was established. The obtained results indicate that the FXG solution prepared with 270 Bloom gelatin presents good performance, similar to that presented by the FXG solution prepared with 300 Bloom gelatin and its use can be recommended owing to the low cost and the availability in local market.

Cavinato, C. C.; Campos, L. L.

2010-11-01

120

Study of Fricke gel dosimeter response for different gel quality  

Energy Technology Data Exchange (ETDEWEB)

The Fricke xylenol gel (FXG) dosimeter has been studied for application in radiotherapy because it is capable of to measure the spatial distribution of radiation doses. The dosimetry is based on the oxidation of ferrous (Fe{sup 2+}) to ferric (Fe{sup 3+}) ions radiation induced, related to the radiation dose. The gel material usually employed is the 300 Bloom gelatin, which is imported and very expensive in Brazil. Aiming to analyze the viability of to use a locally produced and low cost gel material, in this work the spectrophotometric responses of FXG solutions prepared using 270 Bloom gelatin commercially available and 300 Bloom gelatin imported were compared. The absorption spectra of solutions prepared with 5% by weight 270 and 300 Bloom gelatins non-irradiated and irradiated with {sup 60}Co gamma radiation in the dose range between 0.5 and 100 Gy were analysed, the dose-response curves were evaluated and the useful dose range was established. The obtained results indicate that the FXG solution prepared with 270 Bloom gelatin presents good performance, similar to that presented by the FXG solution prepared with 300 Bloom gelatin and its use can be recommended owing to the low cost and the availability in local market.

Cavinato, C C; Campos, L L, E-mail: ccavinato@ipen.b [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP (Brazil)

2010-11-01

 
 
 
 
121

Cumulative irritation potential among metronidazole gel 1%, metronidazole gel 0.75%, and azelaic acid gel 15%.  

Science.gov (United States)

Topical therapy for rosacea aims to reduce inflammatory lesions and decrease erythema but can carry side effects such as stinging, pruritus, and burning. Metronidazole and azelaic acid gel 15% are U.S. Food and Drug Administration-approved for the treatment of rosacea. The current study was conducted to assess the cumulative irritation potential of 2 formulations of metronidazole 0.75% gel and 1% gel--and azelaic acid gel 15% over 21 days (N=36). Results of this study demonstrated a significantly greater poten tial for irritation from azelaic acid compared with metronidazole gel 0.75% (P < .0001), which had significantly greater potential for irritation compared with metronidazole gel 1% (P = .0054). Metronidazole gel 1% had a similar profile to white petrolatum. PMID:17500380

Colón, Luz E; Johnson, Lori A; Gottschalk, Ronald W

2007-04-01

122

Matrices for capillary gel electrophoresis--a brief overview of uncommon gels.  

Science.gov (United States)

This article gives an overview of uncommon replaceable matrices (gels) for capillary gel electrophoresis. This electrophoretic technique is useful mainly for the separation and analysis of biopolymers-nucleic acids and their fragments, and proteins/peptides. Commonly used gels are not reviewed. Those mentioned and discussed here are gels containing saccharides, newly developed acrylamide-based gels and thermoadjustable viscosity polymers, namely triblock copolymers and grafted polyacrylamide. PMID:16779791

Miksík, Ivan; Sedláková, Pavla; Mikulíková, Katerina; Eckhardt, Adam; Cserhati, Tibor; Horváth, Tibor

2006-01-01

123

Equations of state for ideal elastomeric gels  

Science.gov (United States)

Submerged in a solvent-containing environment and subject to applied forces, a covalent polymer network absorbs the solvent and deforms, forming an elastomeric gel. The equations of state are derived under two assumptions. First, the amount of the solvent in the gel varies when the gel changes volume, but remains constant when the gel changes shape. Second, the Helmholtz free energy of the gel is separable into the contribution due to stretching the network and that due to mixing the polymer and the solvent. We demonstrate that these equations of state fit several sets of experimental data in the literature remarkably well.

Cai, Shengqiang; Suo, Zhigang

2012-02-01

124

Counting efficiency of scintillating gels  

International Nuclear Information System (INIS)

Scintillating gels that are suitable for the counting of insoluble radioact+ve samples, sometimes exhibit in addition a higher scintillation yield than the corresponding liquid scintillators. This property, observable when silica is added into dioxane liquid scintillators, is inherent in some primary solutes (PPO, PBD, butyl-PBD) while not obvious for others (CPO, PFD, BPO, ?NPO). Quenching properties of chlorinated compounds (CHCl3, CCl4) and energy transfer mechanisms are not changed by silica addition. On the other hand, PPO, PBD and butyl-PBD fluorescence quantum yields are markedly increased under these conditions, probably because of the higher viscosity of the samples. Another scintillating gel was prepared by the addition of HP55 (hydroxy propyl methyl cellulose phthalate) into PPO-dioxane liquid scintillator; its scintillation yield is reduced without any change of transfer mechanisms and at the same time PPO fluorescence quantum yield is diminished. A static quenching process by HP55 is likely to occur, which screens the viscosity effect noticed in the presence of Cab-O-Sil. Thus, PPO, PBD and butyl-PBD seem to be the most efficient primary solutes among those studied since they provide gel scintillator giving improved counting efficiency compared to that of liquid scintillator. (author)

125

Risk factors and presence of antibodies to Brucella canis and smooth Brucella in dogs from the municipality of Araguaína, Tocantins, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Canine brucellosis is an infectious disease of worldwide distribution that can affect dogs, wild canids and man. It is caused by Brucella canis, but dogs can also be infected by smooth Brucella such as B. abortus and B. suis. Due to the increasing importance of dogs in our society, to the scarcity of information about canine brucellosis in the country and its zoonotic character, the aims of the present study were (i to conduct a survey on the infection by B. canis and smooth Brucella in dogs from the municipality of Araguaína, Tocantins, Brazil, and (ii to evaluate the risk factors associated with these infections. Sera from 241 dogs were analyzed by agar gel immunodiffusion (AGID to detect B. canisantibodies, and Buffered Acidified Plate Antigen test (BAPA and fluorescence polarization assay (FPA to detect antibodies to smooth Brucella. From the 241 tested dogs, 132 reacted in the AGID and 128 reacted in the BAPA, but only two were positive in FPA. The seroprevalences of B. canis and smooth Brucella infections in dogs in Araguaína were 54.77% (95% CI: 48.25 to 61.17% and 0.83% (95% CI: 0.10 to 2.97%, respectively. The analysis of risk factors showed associations between B. canis infection and vaccination against leptospirosis, and between B. canis infection and use of manufactured food. In conclusion, data from the present study showed a low prevalence of infection by smooth Brucella and a widespread and high prevalence of infection by B. canis in the city of Araguaína, Tocantins, Brazil.

Jordana Almeida Santana

2013-12-01

126

Rheological characterization of Poloxamer 407 nimesulide gels  

Directory of Open Access Journals (Sweden)

Full Text Available The thermal gelling property of Poloxamer 407- nimesulide gels was characterized by rheological studies. Nimesulide, a local anti-inflammatory and anesthetic drug used for the treatment of acute and chronic pain, has a short duration of action and a long-acting single-dose injection would be of clinical importance. Thus a poloxamer 407 gel applied intramuscularly could prolong the release and action of nimesulide. In this study, aqueous gels with nimesulide, containing three different concentrations of Poloxamer 407, were prepared. Viscosity measurements were performed by rheologial studies to obtain the optimal sol-gel transition temperature . Poloxamer 407 gels are pseudoplastic and viscoelastic materials, which have an elastic modulus (G', characteristic of the solid, and a viscous modulus (G'', characteristic of the liquid material. Moreover, being pseudoplastic gels, when they are deformed by shearing, their viscosity decreases. Increase of the polymer concentration increased the viscosity of the gels, which could affect the releasing process of nimesulide. Furthermore, the presence of nimesulide led to a lowering of the sol-gel transition temperature. Keywords: Poloxamer 407 gels; nimesulide; rheological characterization; viscosity; sol-gel transition temperature.

M. N. Freitas

2009-01-01

127

Epidemiologia da infecção pelo vírus da Leucose Enzoótica Bovina (LEB) / Epidemiology of Enzootic Bovine Leukemia (BLV) virus infection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Objetivou-se com este trabalho investigar a presença de anticorpos anti-vírus da leucose enzoótica além de identificar a associação entre variáveis de manejo e soropositividade para essa infecção em bovinos no Estado de Alagoas, Brasil. Foram examinados 17 rebanhos, perfazendo um total de 341 animai [...] s, distribuídos em oito municípios. A pesquisa de anticorpos foi efetuada pela técnica de Imunodifusão em Gel de Ágar (IDGA), utilizando-se o antígeno constituído por lipopolissacarídeos e proteínas do vírus da leucose bovina. Das 341 amostras analisadas, 95 (27,8%) foram positivas e o número de focos constatados foi de 12 (70,6%). Foram observadas diferenças significativas para as variáveis: assistência técnica (p Abstract in english 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 anim [...] als, 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

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

2013-06-01

128

Epidemiologia da infecção pelo vírus da Leucose Enzoótica Bovina (LEB) / Epidemiology of Enzootic Bovine Leukemia (BLV) virus infection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Objetivou-se com este trabalho investigar a presença de anticorpos anti-vírus da leucose enzoótica além de identificar a associação entre variáveis de manejo e soropositividade para essa infecção em bovinos no Estado de Alagoas, Brasil. Foram examinados 17 rebanhos, perfazendo um total de 341 animai [...] s, distribuídos em oito municípios. A pesquisa de anticorpos foi efetuada pela técnica de Imunodifusão em Gel de Ágar (IDGA), utilizando-se o antígeno constituído por lipopolissacarídeos e proteínas do vírus da leucose bovina. Das 341 amostras analisadas, 95 (27,8%) foram positivas e o número de focos constatados foi de 12 (70,6%). Foram observadas diferenças significativas para as variáveis: assistência técnica (p Abstract in english 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 anim [...] als, 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

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

129

Gel barrier formation in unsaturated porous media.  

Science.gov (United States)

The gel barrier formation by a gelling liquid (Colloidal Silica) injection in an unsaturated porous medium is investigated by developing a mathematical model and conducting numerical simulations. Gelation process is initiated by adding electrolytes such as NaCl, and the gel phase consisting of cross-linked colloidal silica particles grows as the gelation process proceeds. The mathematical model describing the transport and gelation of Colloidal Silica (CS) is based on coupled mass balance equations for the gel mixture (the sol phase plus the gel phase), gel phase (cross-linked colloidal silica particles plus water captured between cross-linked particles), and colloidal silica particles (discrete and cross-linked) and NaCl in the sol (suspension of discrete colloidal silica particles in water) and gel phases. The solutions in terms of volumetric fraction of the gel phase yield the gel mixture viscosity via the dependency on the volumetric fraction of gel phase. This dependency is determined from a kinetic gelation model with time-normalized viscosity curves. The proposed model is verified by comparing experimentally and numerically determined hydraulic conductivities of gel-treated soil columns at different CS injection volumes. The numerical experiments indicate that an impermeable gel layer is formed within the time period twice the gel-point in a one-dimensional flow system. At the same normalized time corresponding to twice the gel-point, the CS solutions with lower NaCl concentrations result in further migration and poor performance in plugging the pore space. The viscosity computation proposed in this study is compared with another method available in the literature. It is observed that the other method estimates the viscosity at the mixing zone higher than the one proposed by the authors. The proposed model can simulate realistic injection scenarios with various combinations of operating parameters such as NaCl concentration and NaCl mixing time, and thus providing guidelines in performing this technology on site. PMID:12076024

Kim, Meejeong; Corapcioglu, M Yavuz

2002-05-01

130

Development of Texture Model in the Fish Gels Using Eigen-gel Patterns  

Directory of Open Access Journals (Sweden)

Full Text Available This study proposes two texture development models for Cod surimi gel. Dimensionality of the training data sets (12 patterns of surimi gel strength are reduced to four eigen-gel patterns using an unsupervised method, the PCA method. Then we obtain an eigen-gel pattern for each cluster. Two texture models, consecutive and competitive-consecutive first order reactions are developed based on an eigen-gel pattern for each cluster. The correlation coefficient method is introduced to achieve a good identification rate of similarity between the two proposed methods and the eigen-gel pattern for each cluster.

Sirima Chinnasarn

2006-01-01

131

Active Gel Model of Amoeboid Cell Motility  

CERN Document Server

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.

Callan-Jones, A C

2013-01-01

132

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

Science.gov (United States)

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 ? 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.

Pila?ová (Vávr?), Kate?ina; Kozubíková, Petra; Šolc, Jaroslav; Sp?vá?ek, Václav

2014-11-01

133

Padronização do Elisa indireto e Western Blot para diagnóstico da artrite-encefalite caprina / Standardization of indirect Elisa and Western Blot for diagnosis of Caprine Arthritis-Encephalitis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A artrite-encefalite caprina (CAE) é diagnosticada rotineiramente pela técnica de imunodifusão em gel de agarose (IDGA), que é considerada pouco sensível. Objetivou-se com este estudo padronizar testes de Elisa-i e Western Blot (WB) para diagnóstico precoce de anticorpos em caprinos contra CAEV e co [...] mparar os resultados obtidos nesses testes com a prova de IDGA. Para a padronização dos testes Elisa-i e WB, utilizaram-se diferentes concentrações e diluições de antígeno, soros e conjugado. No Elisa-i, adotaram-se microplacas rígidas com 96 poços, sendo a combinação de concentração de 0,5µg/poço de antígeno e diluições de 1:100 de soro e 1:1500 de conjugado a que apresentou melhor resultado. No WB foram utilizadas membranas de nitrocelulose, definindo-se as diluições de 1:50 de soro e 1:15000 de conjugado. Para avaliar o desempenho das técnicas, 222 amostras de soro caprino foram testadas e os dados obtidos foram comparados com o IDGA. A sensibilidade e a especificidade do Elisa-i/IDGA, WB/IDGA e WB/Elisa-i foram de 70% e 91%, 100% e 72,6%, 84,6% e 76,5%, concomitantemente. O índice Kappa desses testes foi de 0,35, 0,2 e 0,36, respectivamente. As técnicas de Elisa-i e WB apresentaram-se mais sensíveis que a IDGA, podendo ser utilizadas como ferramentas para o diagnóstico precoce da CAE. Abstract in english Caprine arthritis-encephalitis (CAE) is routinely diagnosed with the Agarose Gel Immunodiffusion (AGID) technique, which is considered to have low sensitivity. The objective of this study was to standardize testing i-Elisa and Western Blot for early detection of antibodies against CAEV in goats and [...] compare the results obtained in these tests with proof of AGID. For standardization of i-Elisa and WB, different concentrations and dilutions of antigen, sera and conjugate were used. In the i-Elisa, rigid microplate with 96 wells was adopted, and the combination that showed the best result was a concentration of 0.5µg/ well of antigen and dilutions of the serum of 1:100 and conjugate of 1:1500. In the WB nitrocellulose membranes were used, and the dilutions of the serum were defined at 1:50 and conjugate at 1:15000. To evaluate the performance of the techniques, 222 goat serum samples were tested and the data were compared with the AGID. The sensitivity and specificity of Elisa-i/IDGA, WB/AGID and WB/Elisa-i were 70% and 91%, 100% and 72.6%, 84.6% and 76.5%, concomitantly. The Kappa index of these tests was 0.35, 0.2 and 0.36, respectively. The i-Elisa and WB techniques were more sensitive than the AGID and can be used as tools for early diagnosis of CAE.

A.S., Rodrigues; R.L.L., Brito; R.R., Pinheiro; R.P., Dias; S.M., Alves; T.S., Souza; K.C., Souza; D.A.A., Azevedo; A., Andrioli; D.C.T., Magalhães; M.F.S., Teixeira.

2014-04-01

134

Padronização do Elisa indireto e Western Blot para diagnóstico da artrite-encefalite caprina / Standardization of indirect Elisa and Western Blot for diagnosis of Caprine Arthritis-Encephalitis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A artrite-encefalite caprina (CAE) é diagnosticada rotineiramente pela técnica de imunodifusão em gel de agarose (IDGA), que é considerada pouco sensível. Objetivou-se com este estudo padronizar testes de Elisa-i e Western Blot (WB) para diagnóstico precoce de anticorpos em caprinos contra CAEV e co [...] mparar os resultados obtidos nesses testes com a prova de IDGA. Para a padronização dos testes Elisa-i e WB, utilizaram-se diferentes concentrações e diluições de antígeno, soros e conjugado. No Elisa-i, adotaram-se microplacas rígidas com 96 poços, sendo a combinação de concentração de 0,5µg/poço de antígeno e diluições de 1:100 de soro e 1:1500 de conjugado a que apresentou melhor resultado. No WB foram utilizadas membranas de nitrocelulose, definindo-se as diluições de 1:50 de soro e 1:15000 de conjugado. Para avaliar o desempenho das técnicas, 222 amostras de soro caprino foram testadas e os dados obtidos foram comparados com o IDGA. A sensibilidade e a especificidade do Elisa-i/IDGA, WB/IDGA e WB/Elisa-i foram de 70% e 91%, 100% e 72,6%, 84,6% e 76,5%, concomitantemente. O índice Kappa desses testes foi de 0,35, 0,2 e 0,36, respectivamente. As técnicas de Elisa-i e WB apresentaram-se mais sensíveis que a IDGA, podendo ser utilizadas como ferramentas para o diagnóstico precoce da CAE. Abstract in english Caprine arthritis-encephalitis (CAE) is routinely diagnosed with the Agarose Gel Immunodiffusion (AGID) technique, which is considered to have low sensitivity. The objective of this study was to standardize testing i-Elisa and Western Blot for early detection of antibodies against CAEV in goats and [...] compare the results obtained in these tests with proof of AGID. For standardization of i-Elisa and WB, different concentrations and dilutions of antigen, sera and conjugate were used. In the i-Elisa, rigid microplate with 96 wells was adopted, and the combination that showed the best result was a concentration of 0.5µg/ well of antigen and dilutions of the serum of 1:100 and conjugate of 1:1500. In the WB nitrocellulose membranes were used, and the dilutions of the serum were defined at 1:50 and conjugate at 1:15000. To evaluate the performance of the techniques, 222 goat serum samples were tested and the data were compared with the AGID. The sensitivity and specificity of Elisa-i/IDGA, WB/AGID and WB/Elisa-i were 70% and 91%, 100% and 72.6%, 84.6% and 76.5%, concomitantly. The Kappa index of these tests was 0.35, 0.2 and 0.36, respectively. The i-Elisa and WB techniques were more sensitive than the AGID and can be used as tools for early diagnosis of CAE.

A.S., Rodrigues; R.L.L., Brito; R.R., Pinheiro; R.P., Dias; S.M., Alves; T.S., Souza; K.C., Souza; D.A.A., Azevedo; A., Andrioli; D.C.T., Magalhães; M.F.S., Teixeira.

135

Polymer gel electrolytes for lithium batteries  

International Nuclear Information System (INIS)

The data on the most promising polymer gel electrolytes for lithium batteries published in the past decade are surveyed and described systematically. Gel electrolytes with matrices of polyethylene oxide, poly(vinylidene fluoride) and its copolymer with hexafluoropropylene, poly(methyl methacrylate), polyacrylonitrile, poly(vinyl chloride) and polyacrylates are discussed. A special section is devoted to gel electrolytes with ionic liquids as the solvents. The bibliography includes 160 references.

136

Electrochemical detection of gel microparticles in seawater  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present the first atomic force microscopy (AFM) images of the native marine gel network and a new type of electrochemical signals of individual gel microparticles in seawater. Gel microparticles in seawater are selectively detected through specific amperometric signals using a dropping mercury electrode (DME) as a sensor. We have demonstrated that organic microparticles naturally present in Northern Adriatic seawater can be detected as single particles and sorted at the DME/seawater interf...

Svetlic?ic?, Vesna; Balnois, Eric; Z?utic?, Vera; Chevalet, Jean; Hozic? Zimmermann, Amela; Kovac?, Solveg; Vdovic?, Neda

2006-01-01

137

Computer Analysis of Two-Dimensional Gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work identifies statistical algorithms which need to be included in analysis of two-dimensional gels for accurate determination of differential changes. Two-dimensional electrophoresis is a powerful tool for determining differential protein expression in complex mixtures, but the methodology, to date, is not producing expected results due to the degree of gel variability. The new DIGE procedure, comparing two samples in the same gel, does eliminate some of the variability introduced with...

Goldfarb, Marcia

2007-01-01

138

Comparative study of haemagglutination inhibition, Agar gel precipitation test, Serum neutralization and Enzyme linked immunosorbent assay for detection to avian influenza viruses  

Directory of Open Access Journals (Sweden)

Full Text Available The sensitivity, specificity and reproducibility of the serological tests for detection of avian in-fluenza viruses were carried-out by using Ham- agglutination inhibition (HI, Agar gel precipita-tion test (AGPT, and Enzyme linked immu-nosorbent assay (ELISA and Serum neutraliza-tion test. The geometric mean titre (GMT of hae- magglutination inhibition antibodies recor- ded as log2 indicated that the post vaccination titres in the field were on higher side i.e., 7.9 for H7 and 5.9 for H9. The correlation between HI titre and AGPT affirmed that for the AGPT test need high antibody titre for positive reaction. The pooled sera were also used to correlate the se-rum neutralization test and enzyme linked im- muno-sorbent assay. The serial two fold dilute- ons were tested for the serum neutralization ac- tivity and concluded that the HI titre log2 4 pro-vided 100% protection, than 52% and 45% pro-tection in 1:2 and 1:4 dilution was recorded, respectively. Similarly, the ELISA test showed positive results up to 1:16 HI titre, i.e. log2 4 and confirmed the linear relation between these two serological tests. In HI test, the concentration of antigen can influence the result. It also needs careful preparation of concentration of eryth-rocyte suspension. Agar Gel immuno-diffusion is basically a qualitative test as it can not de-termine the quantity of antigen or antibody with the help of this test. It lacks the level of sensi-tivity as offered by other test. If serum neutrali-zation test is performed on a pooled serum sam- ples, then it could lead to a false conclusion on antibodies status. ELISA is most sensitive, spe-cific and accurate as compare to all other sero-logical tests.

Ghluam Hussain Jaffar

2010-02-01

139

Principles of Gel Permeation Chromatography  

Science.gov (United States)

Principles of Gel Permeation Chromatography presents the principles of gel permeation chromatography (GPC) for students in introductory undergraduate courses of chemistry and biochemistry. These principles are presented in four sections: Introduction, Real Lab, Virtual Lab, and Microscopic Model. The Introduction and Real Lab sections present a brief view of the basic experimental apparatus typically used in laboratory GPC in order to provide a concrete connection of the real process of separation. The basic elements of column chromatography, emphasizing the stationary and mobile phases, are presented in the Introduction, followed by a sequence of pictures and texts describing major steps in GPC analysis in the Real Lab section. The Virtual Lab section is a simulator. Three samples are available for a virtual GPC experiment: sample 1, containing hemoglobin; sample 2, containing methylene blue; and sample 3, containing both methylene blue and hemoglobin. Each sample undergoes a virtual separation run, which is dynamically represented in three ways in the software: a virtual column, the collected fractions, and a virtual chromatogram. This threefold representation allows the simultaneous view of key aspects of the process to demonstrate the correlation between the experimental procedure and the resulting chromatogram.

140

Gel nano-particulates against radioactivity  

International Nuclear Information System (INIS)

The Argonne research center (USA) has developed a 'super-gel' compound, a polymer close to those used in baby's diapers, which can reach a 90% efficiency in the radioactive decontamination of porous materials, like bricks or concrete. The contaminated materials are sprayed with a mixture of polymer gel and wetting agent with nano-particulates in suspension. Under the action of the wetting agent, radioactivity migrates from the pores to the gel and is trapped by the nano-particulates. The drying and recycling of the gel allows to reduce the volume of radioactive wastes. Short paper. (J.S.)

 
 
 
 
141

Stacking gels: A method for maximising output for pulsed-field gel electrophoresis  

Directory of Open Access Journals (Sweden)

Full Text Available Pulsed field gel electrophoresis (PFGE, the gold standard of molecular typing methods, has a major disadvantage of an unusually long electrophoretic time. From the original protocol of 6 days, it was modified to 3 days and subsequently to a single day. We describe the procedure of stacking five to six gels one on top of another in order to increase and maximize the output in a shorter time without compromising the resolution and reproducibility. All the variables that affect pulsed field gels during electrophoresis were taken into consideration. We firstly optimized the parameters to be used and secondly determined whether stacking of five to six gels had any effect on the molecular separation during electrophoresis in comparison with a single gel run. DNA preparation, restriction, electrophoresis, staining and gel documentation was carried out based on previously published methods. Gels were analysed using BioNumerics and dice coefficient and unweighted pair group methods were used to generate dendrograms based on 1.5% tolerance values. Identical band profiles and band resolution-separation were seen in the PFGE patterns with single gel and multiple stacking gels. Cluster analysis further strengthened the fact that results from stacking gels were reproducible and comparable with a single gel run. This method of stacking gels saves time and maximizes the output at the same time. The run time for a single gel was about 28 hours, but with six stacked gels the run time was 54 hours compared with 28 x 6 = 168 hours if they were run separately as single gels thus saving time of 67.86%. Beside the big factor of saving time, stacking gels save resources (electricity, reagents, water, chemicals and working time by increasing the sample throughput in a shorter time without compromising on quality of data. But optimization of working parameters is vital depending on the PFGE system used.

Heng See

2009-01-01

142

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

Directory of Open Access Journals (Sweden)

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.

Julio A. Mesquita

1972-01-01

143

Sorptive diffusion in clay gels  

International Nuclear Information System (INIS)

Additional protection for the underground storage of high-level nuclear wastes can be provided by an engineered barrier or backfill material. If properly designed, such a barrier can significantly retard the migration of toxic ions even after failure of the waste canister. The backfill material should be inexpensive, relatively impermeable, thermally stable, highly sorptive to toxic ions, compatible with the host rock, easily applied, and, if possible, a fissure sealant. One material that apparently meets most of these qualifications is a swelling clay known as smectite or montmorillonite. The purpose of this research is to investigate experimentally the migration of representative nuclides in swollen clay gels and to formulate a quantitative transport model allowing reliable design of such an engineered barrier

144

Viscoelastic Properties of Vitreous Gel  

Science.gov (United States)

We studied the rheological properties of porcine vitreous humor using a stressed-control shear rheometer. All experiments were performed in a closed environment at body temperature to mimic in-vivo conditions. We modeled the creep deformation using a two-element retardation spectrum model. By associating each element of the model to an individual biopolymeric system in the vitreous gel, a separate response to the applied stress was obtained from each component. The short time scale was associated with the collagen structure, while the longer time scale was related to the microfibrilis and hyaluronan network. We were able to distinguish the role of each main component from the overall rheological properties. Knowledge of this correlation enables us to relate the physical properties of vitreous to its pathology, as well as optimize surgical procedures such as vitrectomy.

Pirouz Kavehpour, H.; Sharif-Kashani, Pooria

2010-11-01

145

Staining proteins in gels with coomassie blue.  

Science.gov (United States)

INTRODUCTIONThe most commonly used dye for visualizing proteins in SDS-PAGE gels is Coomassie Brilliant Blue R250 (CBR-250) because of its relatively high sensitivity. This protocol describes the standard CBR-250 staining method, along with a simple method for preparing stained gels for long-term storage. PMID:21357065

Simpson, Richard J

2007-01-01

146

Effect of iron gel on dentin permeability  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este estudo objetivou avaliar in vitro o efeito do gel experimental contendo ferro na redução da condutividade hidráulica na dentina. Trinta e seis discos de dentina humana de 1 mm de espessura, foram obtidos de terceiros molares extraídos divididos em 3 grupos de 10 espécimes cada. Os grupos foram [...] divididos nos seguintes grupos experimentais: F- flúor gel a 1,23%, pH 4,1; O- gel de oxalato de potássio a 3%, pH 4,1; I- gel de sulfato ferroso FeSO4 a 10 mmol/L, pH 4,1. Os géis foram aplicados na dentina sob as diferentes condições: após o ácido fosfórico a 37% a antes do ácido cítrico a 6%. Os resultados foram analisados por ANOVA e teste de Tukey, com nível de significância de 5%. Todos os grupos (gel de flúor, oxalato de potássio e gel de ferro) não apresentaram diferenças significativas entre si para todas as condições testadas, exceto na presença da smear layer (p Abstract in english This study evaluated in vitro the effect of an experimental gel containing iron on the reduction of hydraulic conductance of dentin. Thirty-six 1-mm-thick dentin discs obtained from extracted human third molars were divided into 3 groups of 10 specimens each. The groups corresponded to the following [...] experimental materials: 1.23% acidulated phosphate fluoride gel, pH 4.1; 3% potassium oxalate gel, pH 4.1 (Oxa-Gel®); and iron sulfate gel (10 mmol/L FeSO4), pH 4.1. The gels were applied to dentin under the following conditions: after 37% phosphoric acid and before 6% citric acid. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no significant differences (p0.05) among the gels. This study suggests that the iron gel promoted reduction in dentin permeability comparable to that of the other agents and thus may be considered a good clinical alternative for the treatment of dentin hypersensitivity.

Sílvia Helena de Carvalho, Sales-Peres; João Victor Donazan, Reinato; André de Carvalho, Sales-Peres; Juliane Avansini, Marsicano.

147

Catalytic control over supramolecular gel formation  

Science.gov (United States)

Low-molecular-weight gels show great potential for application in fields ranging from the petrochemical industry to healthcare and tissue engineering. These supramolecular gels are often metastable materials, which implies that their properties are, at least partially, kinetically controlled. Here we show how the mechanical properties and structure of these materials can be controlled directly by catalytic action. We show how in situ catalysis of the formation of gelator molecules can be used to accelerate the formation of supramolecular hydrogels, which drastically enhances their resulting mechanical properties. Using acid or nucleophilic aniline catalysis, it is possible to make supramolecular hydrogels with tunable gel-strength in a matter of minutes, under ambient conditions, starting from simple soluble building blocks. By changing the rate of formation of the gelator molecules using a catalyst, the overall rate of gelation and the resulting gel morphology are affected, which provides access to metastable gel states with improved mechanical strength and appearance despite an identical gelator composition.

Boekhoven, Job; Poolman, Jos M.; Maity, Chandan; Li, Feng; van der Mee, Lars; Minkenberg, Christophe B.; Mendes, Eduardo; van Esch, Jan H.; Eelkema, Rienk

2013-05-01

148

Controlling the Morphology of Carbon Gels  

Directory of Open Access Journals (Sweden)

Full Text Available Carbon gels are unique porous carbons, which aretypically obtained through the carbonization ofresorcinol-formaldehyde gels. This material ispractically an aggregate of nanometer-sized carbonparticles. Nanopores, mostly in the size range ofmesopores, exist between the particles. Smallerpores, micropores being the majority, also exist withinthe particles. Therefore, this material has ahierarchical pore system in which short microporesare directly connected to mesopores.The precursor of carbon gels can be obtained throughsol-gel transition. Therefore there is a high possibilitythat the morphology of the resulting carbon can beeasily controlled using various molding methods.We have actually challenged the controlling of themorphology of carbon gels, and have succeeded inobtaining them in the form of disks, microspheresand microhoneycombs. Details of such carbon gelswill be reported.

S. R. Mukai

2012-12-01

149

Moisture Transport in Silica Gel Particle Beds: I. Theoretical Study  

Energy Technology Data Exchange (ETDEWEB)

Diffusion mechanisms of moisture within silica gel particles are investigated. It is found that for microporous silica gel surface diffusion is the dominant mechanism of moisture transport, while for macroporous silica gel both Knudsen and surface diffusion are important.

Pesaran, A. A.; Mills, A. F.

1986-08-01

150

21 CFR 520.1453 - Moxidectin and praziquantel gel.  

Science.gov (United States)

...2010-04-01 false Moxidectin and praziquantel gel. 520.1453 Section 520.1453 Food and... § 520.1453 Moxidectin and praziquantel gel. (a) Specifications . Each milliliter of gel contains 20 milligrams (mg) (2.0...

2010-04-01

151

21 CFR 524.660b - Dimethyl sulfoxide gel.  

Science.gov (United States)

... 2010-04-01 false Dimethyl sulfoxide gel. 524.660b Section 524.660b Food and...ANIMAL DRUGS § 524.660b Dimethyl sulfoxide gel. (a) Specifications. Dimethyl sulfoxide gel, veterinary contains 90 percent dimethyl...

2010-04-01

152

21 CFR 872.1730 - Electrode gel for pulp testers.  

Science.gov (United States)

... false Electrode gel for pulp testers. 872.1730 Section...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1730 Electrode gel for pulp testers. (a) Identification. An electrode gel for pulp testers is a device...

2010-04-01

153

Electromechanical coupling in polyelectrolyte gels  

Science.gov (United States)

This work concerns the systematic characterization of the electromechanical coupling in polyelectrolyte gels (PGs) in correlation with their structure and physical properties in view of their potential application as pressure sensors. PGs are electroactive polymers that respond with an electrical potential difference to gradients in mechanical stress and vice versa. So far, these materials have mainly been studied as electrical actuators, but they can also be used as mechanical sensors. Polyelectrolyte gels are biocompatible, and could form the basis for incorporating tactile sensitivity into artificial skin systems. However, how PGs respond to mechanical stimuli in relation to their structure and electrochemical properties has not been studied systematically in a quantitative manner. In this work, the physical-electrochemical properties of copolymers of acrylamide and acrylic acid of varying compositions were characterized in terms of their equilibrium swelling degree, elastic modulus and Donnan potential. Experimental results were tested against the theory of large deformation and electrochemistry of PGs recently developed by Hong et al. Systematic characterization of the electromechanical coupling in PGs was carried out using a new quantitative test based on the indentation of a flat polymer sample with a spherical indenter, while the potential was monitored with an array of planar electrodes. The experimental results suggest that electromechanical coupling in soft PGs directly subjected to a pressure gradient can be understood as a pressure modulation of the Donnan potential. The idea of the potential application of PGs as pressure transducers was illustrated by showing the prototype of the PG spatially resolved sensor capable of distinguishing between sharp and blunt loads and the prototype of the PG pressure sensor in a microfluidic chip. Spatial resolution of both prototypes was solely given by the resolution of the patterned electrodes. The design framework of the potential application of PGs as sensing layers was discussed with a view to the limitations imposed by the increased electrical impedance and reduced signal-to-noise ratio of the voltage measurements on small-length scales. These limitations were experimentally verified by quantifying the electromechanical response with an array of planar electrodes of systematically varying size.

Prudnikova, Katsiaryna I.

154

Sol-Gel Manufactured Energetic Materials  

Science.gov (United States)

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

Simpson, Randall L. (Livermore, CA); Lee, Ronald S. (Livermore, CA); Tillotson, Thomas M. (Tracy, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Swansiger, Rosalind W. (Livermore, CA); Fox, Glenn A. (Livermore, CA)

2005-05-17

155

Comparative study of sol gel-hydrothermal and sol gel synthesis of titania silica composite nanoparticles  

Science.gov (United States)

Titania-silica composite nanoparticles were prepared by sol-gel-hydrothermal and sol-gel routes, respectively, and their physico-chemical and photocatalytic properties were compared. The results of XRD, TEM and BET surface areas showed that sol-gel-hydrothermal route led to anatase titania-silica composite nanoparticles with large specific surface area, but the sol-gel route tended to form mixture of anatase and rutile. The composite nanoparticles prepared by sol-gel-hydrothermal route had better thermal stability against phase transformation from anatase to rutile, agglomeration and particle growth than those prepared by sol-gel route. On the basis of XRD, FT-IR, XPS and 29Si MAS-NMR, a strong interaction was found between SiO 2 and TiO 2, and Ti-O-Si bonds formed during both the two routes. But more Ti-O-Si bonds formed in the composite nanoparticles prepared by sol-gel-hydrothermal route than those prepared by sol-gel route. As a result, the titania-silica composite nanoparticles prepared by sol-gel-hydrothermal route exhibited higher photocatalytic activity in decomposition of methylene blue than that prepared by sol-gel route, and it had excellent photocatalytic activity even after calcined at 1000 °C.

Li, Zhijie; Hou, Bo; Xu, Yao; Wu, Dong; Sun, Yuhan; Hu, Wei; Deng, Feng

2005-05-01

156

Evaluation of radiochromic gel dosimetry and polymer gel dosimetry in a clinical dose verification  

Science.gov (United States)

A quantitative comparison of two full three-dimensional (3D) gel dosimetry techniques was assessed in a clinical setting: radiochromic gel dosimetry with an in-house developed optical laser CT scanner and polymer gel dosimetry with magnetic resonance imaging (MRI). To benchmark both gel dosimeters, they were exposed to a 6 MV photon beam and the depth dose was compared against a diamond detector measurement that served as golden standard. Both gel dosimeters were found accurate within 4% accuracy. In the 3D dose matrix of the radiochromic gel, hotspot dose deviations up to 8% were observed which are attributed to the fabrication procedure. The polymer gel readout was shown to be sensitive to B0 field and B1 field non-uniformities as well as temperature variations during scanning. The performance of the two gel dosimeters was also evaluated for a brain tumour IMRT treatment. Both gel measured dose distributions were compared against treatment planning system predicted dose maps which were validated independently with ion chamber measurements and portal dosimetry. In the radiochromic gel measurement, two sources of deviations could be identified. Firstly, the dose in a cluster of voxels near the edge of the phantom deviated from the planned dose. Secondly, the presence of dose hotspots in the order of 10% related to inhomogeneities in the gel limit the clinical acceptance of this dosimetry technique. Based on the results of the micelle gel dosimeter prototype presented here, chemical optimization will be subject of future work. Polymer gel dosimetry is capable of measuring the absolute dose in the whole 3D volume within 5% accuracy. A temperature stabilization technique is incorporated to increase the accuracy during short measurements, however keeping the temperature stable during long measurement times in both calibration phantoms and the volumetric phantom is more challenging. The sensitivity of MRI readout to minimal temperature fluctuations is demonstrated which proves the need for adequate compensation strategies.

Vandecasteele, Jan; De Deene, Yves

2013-09-01

157

Evaluation of radiochromic gel dosimetry and polymer gel dosimetry in a clinical dose verification  

International Nuclear Information System (INIS)

A quantitative comparison of two full three-dimensional (3D) gel dosimetry techniques was assessed in a clinical setting: radiochromic gel dosimetry with an in-house developed optical laser CT scanner and polymer gel dosimetry with magnetic resonance imaging (MRI). To benchmark both gel dosimeters, they were exposed to a 6 MV photon beam and the depth dose was compared against a diamond detector measurement that served as golden standard. Both gel dosimeters were found accurate within 4% accuracy. In the 3D dose matrix of the radiochromic gel, hotspot dose deviations up to 8% were observed which are attributed to the fabrication procedure. The polymer gel readout was shown to be sensitive to B0 field and B1 field non-uniformities as well as temperature variations during scanning. The performance of the two gel dosimeters was also evaluated for a brain tumour IMRT treatment. Both gel measured dose distributions were compared against treatment planning system predicted dose maps which were validated independently with ion chamber measurements and portal dosimetry. In the radiochromic gel measurement, two sources of deviations could be identified. Firstly, the dose in a cluster of voxels near the edge of the phantom deviated from the planned dose. Secondly, the presence of dose hotspots in the order of 10% related to inhomogeneities in the gel limit the clinical acceptance of this dosimetry technique. Based on the results of the micelle gel dosimeter prototype presented here, chemical optimization will be subject of future work. Polymer gel dosimetry is capable of measuring the absolute dose in the whole 3D volume within 5% accuracy. A temperature stabilization technique is incorporated to increase the accuracy during short measurements, however keeping the temperature stable during long measurement times in both calibration phantoms and the volumetric phantom is more challenging. The sensitivity of MRI readout to minimal temperature fluctuations is demonstrated which proves the need for adequate compensation strategies. (paper)

158

Acoustic evaluation of polymer gel dosimeters  

International Nuclear Information System (INIS)

Advances in radiotherapy treatment techniques such as intensity modulated radiotherapy are placing increasing demands on radiation dosimetry for verification of dose distributions in 3D. In response, polymer gel dosimeters that are capable of recording dose distributions in 3D are currently being developed. Recently, a new technique for evaluation of absorbed dose distributions in these dosimeters using ultrasound was introduced. The current work aims to demonstrate the potential of ultrasound as an evaluation technique for polymer gel dosimeters and to investigate the ultrasound properties of two different dosimeter formulations, PAG and MAGIC gels

159

Pulsed field gel electrophoresis a practical guide  

CERN Document Server

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

Birren, Bruce

2012-01-01

160

Reusable gels for germanium-68 sources  

International Nuclear Information System (INIS)

Two water-soluble gels, gelatin and Carbowax, were mixed with radioactive 68Ge solutions and evaluated for their use as long-lived (half-life, 280 days) radioactive sources. These gels melt at 40-50oC and solidify at room temperature. The amount of 68Ge mixed with them can be increased or decreased as needed, eliminating waste of 68Ge. These gel sources also may replace short-lived 68Ga (half-life 68 min) as attenuation correction sources in positron emission tomography (PET) and reduce frequency of source preparation, thus reducing exposure of PET operators to radiation. (author)

 
 
 
 
161

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

International Nuclear Information System (INIS)

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)

162

Frictional properties of gel engineering materials with laser surface texturing  

Science.gov (United States)

Several synthesis methods have been devised to improve the mechanical strength of gels extraordinarily after 2001. It was a trigger to use gels as a new industrial materials, since gels had been considered difficult for industrial materials because of their weakness. In a recent study, we had designed transparency shape memory gels for the first time. Shape memory gels are one of the gels with characteristic networks, and have a shape memory function by copolymerizing an acrylic monomer with a hydrophobic long alkyl side group. It is well known that the mechanical properties such as Young's modulus and friction coefficient of shape memory gels depend on temperature. In this study, we tried to change the frictional properties of shape memory gels by laser surface texturing. Two types of processed surface were prepared. The hexagonal close packed pattern and the square close packed pattern of dimples were formed on the surface of gel sheets with CO2 laser. The intensity of laser was optimized to avoid cutting gels. The friction coefficients of unprocessed gels and two types of processed gels were measured by ball-on-disk method. Measurement partner material was sodalime glass ball. The measurement results of processed gels showed clear differences from unprocessed gels. The friction coefficients of processed gels were larger than unprocessed gels. However, these results specifically showed the velocity dependence. It indicates that surface texturing enable to control the friction coefficient of polymer gels by surface pattern and velocity.

Yamada, Naoya; Gong, Jin; Kabir, M. Hasnat; Makino, Masato; Maekawa, Keisuke; Wada, Masato; Furukawa, Hidemitsu

2014-03-01

163

On the Existence of Gel-Glasslike Transition Point in Biopolymer Gels  

Science.gov (United States)

Existence of a gel-glasslike transition in biopolymer gels such as egg-white, DNA, RNA/DNA mixtures, gelatin, agarose is demonstrated in the drying process, and discussions are made on free water and bound water in the gel to glass change. A drastic decrease in the weight of egg-white gel was observed during drying at 25°C for 0 - 100 hours and a gradual decrease was observed for 100 - 450 hours. The first and second stages are due to the loss of free and bound water molecules in the egg-white gel, respectively. This was confirmed by a time domain reflectometry (TDR) measurement. Existence of a gel-glasslike transition may be a common phenomenon for materials in which the molecular network contains free and bound water molecules.

Takushi, E.

164

K-Basin gel formation studies  

International Nuclear Information System (INIS)

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

165

Maize Arabinoxylan Gels as Protein Delivery Matrices  

Directory of Open Access Journals (Sweden)

Full Text Available The laccase induced gelation of maize bran arabinoxylans at 2.5% (w/v in the presence of insulin or ?-lactoglobulin at 0.1% (w/v was investigated. Insulin and ?-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 ?-lactoglobulin (18 kDa, respectively. The results suggest that maize bran arabinoxylan gels can be potential candidates for the controlled release of proteins.

Ana Luisa Martínez-López

2009-04-01

166

Preparation of zirconium molybdate gel generator  

International Nuclear Information System (INIS)

A procedure for preparation of 99mTc generator based on conversion to zirconium molybdate gel of 99Mo produced by neutron activation was reported. The gel was prepared from zirconium oxychloride solution pH 1.6, ammonium molybdate solution pH 3-5 and mole ratio of Zr:Mo 1:1 which had water content about 7-8%. Small generators containing 1-1.5 g of gel were eluted with average efficiencies of 77% and the activity peak in the first 3 ml of 10 ml of saline solution. The amount of Mo and Zr in eluates were below the acceptance limit. The gel generators of activity about 100 mCi were prepared and had the good performance in elutability and stability

167

Oxygen-17 relaxation in aqueous agarose gels  

International Nuclear Information System (INIS)

Nuclear magnetic relaxation of oxygen-17 in H2 17O enriched agarose gels shows that existing explanations of water behaviour are oversimplified. Satisfactory models must include at least three proton phases, two of which involve water molecules. (Auth.)

168

PMMA - Impregnated Silica Gels: Synthesis and Characterization.  

Science.gov (United States)

Shaped microporous silica has been prepared by a sol-gel process. The resulting silicas have 50% open porosity. The open porosity is filled by immersing the shapes in methyl methacrylate (MMA) and polymerizing with ultraviolet radiation. The fully impregn...

B. Abramoff, L. C. Klein

1990-01-01

169

Essential characteristics of polymer gel dosimeters  

Energy Technology Data Exchange (ETDEWEB)

For a physical measurement instrument different requirements have to be fulfilled such as its insensitivity to uncontrollable environmental parameters and its stability. On the other hand, in order to meet an assigned accuracy, all measurement instruments should be operated in an approved manner. Polymer gel dosimeters are unique in their kind as they are able to integrate the dose in three dimensions and can be shaped in a humanoid form. In this paper, we focus on different characteristics that determine the accuracy of polymer gel dosimeters from the point-of-view of their use as 3D dosimeters in radiotherapy. It is shown that the accuracy is highly dependent on the composition of polymer gel. The comparison of the radiological characteristics may help in understanding the underlying mechanisms of the polymer gel dosimeters and in optimizing the chemical composition in terms of both dose and spatial accuracy.

Deene, Y de [MR department (-1K12), Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium)

2004-01-01

170

Sol-gel-derived gold composite electrodes.  

Science.gov (United States)

The preparation, characterization, and analytical utility of sol-gel-derived gold composite electrodes is described. The new metal-ceramic electrodes are comprised of gold powder homogeneously dispersed in a modified silica matrix. They couple the favorable electron-transfer kinetics common to gold surfaces with the regeneration, bulk modification, and versatility features of sol-gel-derived composite materials. The voltammetric characteristics of the composite gold-silica electrodes are explored and compared with conventional gold electrodes. Sol-gel-derived gold biosensors have been prepared by incorporating an oxidase enzyme within the sol-gel gold solution. Analogous thick-film enzyme strips, based on a new screen-printable gold biogel ink, have also been fabricated. To our knowledge, the above represent the first examples of metal-ceramic sensing electrodes and of bulk modification of metallic working electrodes. PMID:21639181

Wang, J; Pamidi, P V

1997-11-01

171

Polymer gel dosimeters with enhanced sensitivity for use in x-ray CT polymer gel dosimetry  

International Nuclear Information System (INIS)

A primary limitation of current x-ray CT polymer gel dosimetry is the low contrast, and hence poor dose resolution, of dose images produced by the system. The low contrast is largely due to the low-dose sensitivity of current formulations of polymer gel for x-ray CT imaging. This study reports on the investigation of new dosimeter formulations with improved dose sensitivity for x-ray CT polymer gel dosimetry. We incorporate an isopropanol co-solvent into an N-isopropylacrylamide-based gel formulation in order to increase the total monomer/crosslinker concentration (%T) within the formulation. It is shown that gels of high %T exhibit enhanced dose sensitivity and dose resolutions over traditional formulations. The gels are shown to be temporally stable and reproducible. A single formulation (16%T) is used to demonstrate the capabilities of the x-ray CT polymer gel dosimetry system in measuring known dose distributions. A 1 L gel volume is exposed to three separate irradiations: a single-field percent depth dose, a two-field 'cross' and a three-field 'test case'. The first two irradiations are used to generate a dose calibration curve by which images are calibrated. The calibrated images are compared with treatment planning predictions and it is shown that the x-ray CT polymer gel dosimetry system is capable of capturing spatial and dose information accurately. The proposed new gel formulation is shown to be sensitive, stable and to improve the dose resolution over current formulations so as to provide a feasible gel for clinical applications of x-ray CT polymer gel dosimetry.

172

Absorption, luminescent and lasing properties of laser dyes in silica gel matrices and thin gel films  

International Nuclear Information System (INIS)

The absorption and emission properties of eight organic compounds in silica gel matrices of different chemical compositions and different types (bulk samples and thin films) are studied upon excitation by a XeCl laser and the second harmonic of a Nd:YAG laser. The mechanisms of the laser-induced changes in the spectral parameters of molecules in silica gel matrices are discussed and the photostability of the laser dyes in silica gel films is estimated. (active media)

173

Polymer gel dosimeters with enhanced sensitivity for use in x-ray CT polymer gel dosimetry  

Science.gov (United States)

A primary limitation of current x-ray CT polymer gel dosimetry is the low contrast, and hence poor dose resolution, of dose images produced by the system. The low contrast is largely due to the low-dose sensitivity of current formulations of polymer gel for x-ray CT imaging. This study reports on the investigation of new dosimeter formulations with improved dose sensitivity for x-ray CT polymer gel dosimetry. We incorporate an isopropanol co-solvent into an N-isopropylacrylamide-based gel formulation in order to increase the total monomer/crosslinker concentration (%T) within the formulation. It is shown that gels of high %T exhibit enhanced dose sensitivity and dose resolutions over traditional formulations. The gels are shown to be temporally stable and reproducible. A single formulation (16%T) is used to demonstrate the capabilities of the x-ray CT polymer gel dosimetry system in measuring known dose distributions. A 1 L gel volume is exposed to three separate irradiations: a single-field percent depth dose, a two-field 'cross' and a three-field 'test case'. The first two irradiations are used to generate a dose calibration curve by which images are calibrated. The calibrated images are compared with treatment planning predictions and it is shown that the x-ray CT polymer gel dosimetry system is capable of capturing spatial and dose information accurately. The proposed new gel formulation is shown to be sensitive, stable and to improve the dose resolution over current formulations so as to provide a feasible gel for clinical applications of x-ray CT polymer gel dosimetry.

Jirasek, A.; Hilts, M.; McAuley, K. B.

2010-09-01

174

Fricke xylenol gel energy dependence  

International Nuclear Information System (INIS)

The advancement of technology has increasingly use the of ionizing radiation mainly in the areas of medicine, industry and research. The development of instruments and methods for an effective performance for detection and measurement of each radiation area was crucial. The literature have demonstrated the effectiveness of the Fricke Xylenol Gel (FXG) as an adequate chemical sensor to be used for dosimetry, once its effective atomic number and density are near to those of the soft tissue. The use of photon beams for therapeutic purpose requires knowledge of their characteristics that can vary for each equipment. Therefore, is important to know all parameters involved for the patient irradiation as the total geometry involved, type of radiation, target material composition and beam energy, that have to be taken into account in the beam dosimetry for the treatment success being the energy parameter is one of the most important. This work was developed to study the energetic dependence of the FXG dosimeter. This chemical solution is made with gelatine 300 Bloom, ferrous ammonium sulfate, xylenol orange, sulfuric acid and Milli-Q water and is based on the Fe+2 oxidation to Fe+3, due to the ionizing radiation leading to the xylenol orange - ferric complex formation, that is linear depend on the absorbed dose. The FXG samples were irradiated with photons of different energies and the absorbance measurements were done with the spectrophotometric technique at the 585 nm, FXG highest absorption peak. The energetic dependence results presented a stronger dependence for low energies and almost independence for high energies, as expected by the interaction of radiation with matter. (author)

175

Fricke xylenol gel energy dependence  

Energy Technology Data Exchange (ETDEWEB)

The advancement of technology has increasingly use the of ionizing radiation mainly in the areas of medicine, industry and research. The development of instruments and methods for an effective performance for detection and measurement of each radiation area was crucial. The literature have demonstrated the effectiveness of the Fricke Xylenol Gel (FXG) as an adequate chemical sensor to be used for dosimetry, once its effective atomic number and density are near to those of the soft tissue. The use of photon beams for therapeutic purpose requires knowledge of their characteristics that can vary for each equipment. Therefore, is important to know all parameters involved for the patient irradiation as the total geometry involved, type of radiation, target material composition and beam energy, that have to be taken into account in the beam dosimetry for the treatment success being the energy parameter is one of the most important. This work was developed to study the energetic dependence of the FXG dosimeter. This chemical solution is made with gelatine 300 Bloom, ferrous ammonium sulfate, xylenol orange, sulfuric acid and Milli-Q water and is based on the Fe{sup +2} oxidation to Fe{sup +3}, due to the ionizing radiation leading to the xylenol orange - ferric complex formation, that is linear depend on the absorbed dose. The FXG samples were irradiated with photons of different energies and the absorbance measurements were done with the spectrophotometric technique at the 585 nm, FXG highest absorption peak. The energetic dependence results presented a stronger dependence for low energies and almost independence for high energies, as expected by the interaction of radiation with matter. (author)

Costa, Rosangela T.; Moreira, Marcos V.; Almeida, Adelaide de, E-mail: dalmeida@ffclrp.usp.b, E-mail: marcos_vasques@yahoo.com.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

2009-07-01

176

Serum release boosts sweetness intensity in gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 gum concentration the size of the pores present in the protein network, the permeability and the serum release increased, as well as the Young's modulus, the fracture stress and the fracture strain....

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

2010-01-01

177

Elasticity of entangled polymer loops Olympic gels  

CERN Document Server

In this note we present a scaling theory for the elasticity of olympic gels, i.e., gels where the elasticity is a consequence of topology only. It is shown that two deformation regimes exist. The first is the non affine deformation regime where the free energy scales linear with the deformation. In the large (affine) deformation regime the free energy is shown to scale as $F \\propto Hookian stress - strain relation is predicted.

Vilgis, T A

1997-01-01

178

A Practical Use for FXG Gel Dosimetry  

Energy Technology Data Exchange (ETDEWEB)

In-phantom Fricke-xylenol orange-gelatin (FXG) gel dosimetry yields three dimensional (3D) dose data for intensity modulated radiation therapy (IMRT) treatment plan verification within 18-24 hours from the point of request. The information obtained from a 3% dose difference, 3 mm distance-to-agreement gamma function comparison between treatment plan dose and gel-measured dose then provides a useful secondary 3D quality assurance check of the treatment plan prior to delivery.

Olding, T; Salomons, G; Darko, J; Schreiner, L J, E-mail: Tim.Olding@krcc.on.c

2010-11-01

179

Sol-Gels for Optical Sensors  

Science.gov (United States)

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

Podbielska, Halina; Ulatowska-Jar?a, Agnieszka; Müller, Gerhard; Eichler, Hans J.

180

Influence of drying conditions of zirconium molybdate gel on performance of {sup 99m}Tc gel generator  

Energy Technology Data Exchange (ETDEWEB)

{sup 99m}Tc can be produced from {sup 99}Mo/{sup 99m}Tc gel generators. These gels are part of the generator and the {sup 99}Mo/{sup 99m}Tc gel generator performance is directly related with gel structure. In this work a series of zirconium molybdate gels have been synthesized and dried under different conditions and characterized using thermal analysis (TGA, DTA), SEM, XRD and porosity measurements. It is found that the water content of the gel determines the structure porosity which allows the diffusion of the {sup 99m}TcO{sub 4}{sup -} ions inside the gel and was directly connected with performance of the {sup 99}Mo/{sup 99m}Tc gel generators. Drying conditions of the gel is as an important factor that influence water content and physical-chemical properties of this gel and must be carefully studied to optimize the properties of the gel generators.

Davarpanah, M.R. [Nuclear Science and Technology Research Institute, Nuclear Science Research School, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of); Attar Nosrati, S. [Nuclear Science and Technology Research Institute, Nuclear Science Research School, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)], E-mail: snosrati@aeoi.org.ir; Fazlali, M.; Kazemi Boudani, M.; Khoshhosn, H.; Ghannadi Maragheh, M. [Nuclear Science and Technology Research Institute, Nuclear Science Research School, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)

2009-10-15

 
 
 
 
181

Treatment of osteochondral injuries with platelet gel  

Science.gov (United States)

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.

Danieli, Marcus Vinicius; da Rosa Pereira, Hamilton; de Sa Carneiro, Carlos Augusto; Felisbino, Sergio Luiz; Deffune, Elenice

2014-01-01

182

Linear and bending actuation of bucky gel  

Science.gov (United States)

In 2003 Takuzo Aida and coworkers reported that single-walled carbon nanotubes (SW-CNTs), when ground with imidazolium based ionic liquids (ILs), create a physical gel, named "bucky gel"1. This gel was used to prepare bimorph electrochemical actuators using a polymer-supported internal IL electrolyte layer2. These actuators can operate in air at low voltage showing improved frequency response and strain. Usual bucky gel actuators rely on a bimorph configuration where the electrodes are used alternatively as cathode and anode thus producing a bending motion. This kind of motion is limiting the possible applications, especially when, like in artificial muscles, linear strain and motion are required. We present a new design for bucky gel actuators capable of both linear and bending motion that uses a three electrode configuration with two active electrodes and a third passive one, made from a metal spring (serpentine shaped), acting as counter plate. We have built such a device and report here its linear and bending actuation performance. In these preliminary experiments we have obtained a linear strain of 0.6% and a bending strain difference between two bucky gel electrodes of 0.25%.

Biso, Maurizio; Ansaldo, Alberto; Vintera, Veronica; Ricci, Davide

2011-04-01

183

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  

Energy Technology Data Exchange (ETDEWEB)

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.

Ricol, S.

1995-10-05

184

Gels de poly(octylthiophène) : cristallisation  

Science.gov (United States)

The study of conjugated poly(octylthiophene) gels by x-ray diffraction and differential calorimetry shows that these networks are semi-crystalline. State of crystallinity, transport properties and large scale heterogeneity seem to be correlated. The determination of this correlation requires a detailed study of the mechanisms of crystallization of these polymer gels, the first results of which are reported here. They show that crystallinity ratios and crystallization rates can be determined by NMR and, as expected, strongly depend on the gels thermodynamic history. L'étude de gels conjugués de poly(octylthiophène) par diffraction des rayons X et par calorimétrie différentielle montre que ces réseaux sont semi-cristallins. Etat de cristallinité, propriétés de transport et état d'hétérogénéité à grande échelle semblent être corrélés. La détermination de cette corrélation nécessite une étude approfondie des mécanismes de cristallisation de ces gels polymères dont les premiers résultats sont reportés ici. Ils montrent que taux de cristallinité et vitesses de cristallisation peuvent être déterminés par RMN et, comme attendu, dépendent fortement de l'histoire thermodynamique des gels.

Pépin-Donat, B.; Sixou, B.; de Geyer, A.; Viallat, A.; Fah. Hin, L. Won

1998-06-01

185

Model carcinogen adsorption dynamics of DNA gel.  

Science.gov (United States)

We have derived theoretical equations describing the adsorption of carcinogen to gels in an immersion medium containing carcinogens. The theory was developed for a cylindrical boundary condition under the assumption of a carcinogen diffusion-limited process combined with the "moving boundary picture (Furusawa et al., 2007)". The time course of the adsorbed carcinogen layer thickness and that of the carcinogen concentration in an immersion medium were expressed by a set of scaled variables, and the asymptotic behavior in the initial stage was derived. Experiments based on the theory were performed using a DNA gel sandwiched between a set of coverglasses in a medium containing acridine orange (AO). The boundary between the AO-adsorbed gel layer and AO-nonadsorbed gel layer was traced during the immersion. The time courses of the AO-adsorbed gel layer thickness and the AO concentration in the immersion medium were well explained by the theory, and the number ratio of the total AO molecules to the adsorption sites in the DNA gel was determined. PMID:24967547

Tomita, Naoko; Naito, Daisuke; Rokugawa, Isamu; Yamamoto, Takao; Dobashi, Toshiaki

2014-09-01

186

Natural gels in the Yucca Mountain Area, Nevada, USA  

International Nuclear Information System (INIS)

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

187

Natural gels in the Yucca Mountain Area, Nevada, USA  

Energy Technology Data Exchange (ETDEWEB)

Relict gels at Yucca Mountain include pore- and fracture-fillings of silica and zeolite related to diagenetic and hydrothermal alteration 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.

Levy, S.S.

1991-12-31

188

Formulation and study of decontamination gels adhering to wall  

International Nuclear Information System (INIS)

The aim of this work is to establish relations between structure and rheological properties, adhesion and drying of a decontamination gel used for the cleansing of spent fuel reprocessing plants. Are successively described here: the formulation of the gels, the rheological behaviour, the relation existing between the drying and the efficiency of the gel, the adhesion of the gel. (O.M.)

189

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

Science.gov (United States)

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

Alam, Mohammad Mydul; Aramaki, Kenji

2008-11-01

190

Interaction between hepatocytes and collagen gel in hollow fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 contr...

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

2009-01-01

191

Sol-gel processing of metal sulfides  

Science.gov (United States)

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 germanium mercaptide evolved during the sol-gel processing of GeSsb2. The titrations were performed in 2-propanol or in a 50-50 vol % mixture of 2-propanol and toluene. The ion selective Ag/Agsb2S electrode was used for equivalence point detection. Study of the Nernst equation shows that complexes were formed at the electrode surface. However, the titration equivalence point volume clearly demonstrates the formation of Agsb2S and Ge(SAg)sbn. In order to explain this discrepancy a new electrode reaction mechanism and a modified Ag/Agsb2S electrode potential equation are proposed. Effects of hydrogen sulfide and germanium ethoxide concentrations, the concentration ratio and temperature on the microstructure of the prepared GeSsb2 gels were studied. It was found that the concentrations of the reactants have the most significant influence on gel structure.

Stanic, Vesha

192

Reprogramming cellular phenotype by soft collagen gels.  

Science.gov (United States)

A variety of cell types exhibit phenotype changes in response to the mechanical stiffness of the substrate. Many cells excluding neurons display an increase in the spread area, actin stress fiber formation and larger focal adhesion complexes as substrate stiffness increases in a sparsely populated culture. Cell proliferation is also known to directly correlate with these phenotype changes/changes in substrate stiffness. Augmented spreading and proliferation on stiffer substrates require nuclear transcriptional regulator YAP (Yes associated protein) localization in the cell nucleus and is tightly coupled to larger traction force generation. In this study, we show that different types of fibroblasts can exhibit spread morphology, well defined actin stress fibers, and larger focal adhesions even on very soft collagen gels (modulus in hundreds of Pascals) as if they are on hard glass substrates (modulus in GPa, several orders of magnitude higher). Strikingly, we show, for the first time, that augmented spreading and other hard substrate cytoskeleton architectures on soft collagen gels are not correlated with the cell proliferation pattern and do not require YAP localization in the cell nucleus. Finally, we examine the response of human colon carcinoma (HCT-8) cells on soft collagen gels. Recent studies show that human colon carcinoma (HCT-8) cells form multicellular clusters by 2-3 days when cultured on soft polyacrylamide (PA) gels with a wide range of stiffness (0.5-50 kPa) and coated with an extracellular matrix, ECM (collagen monomer/fibronectin). These clusters show limited spreading/wetting on PA gels, form 3D structures at the edges, and eventually display a remarkable, dissociative metastasis like phenotype (MLP), i.e., epithelial to rounded morphological transition after a week of culture on PA gels only, but not on collagen monomer coated stiff polystyrene/glass where they exhibit enhanced wetting and form confluent monolayers. Here, we show that HCT-8 cell clusters also show augmented spreading/wetting on soft collagen gels and eventually form confluent monolayers as on rigid glass substrates and MLP is completely inhibited on soft collagen gels. Overall, these results suggest that cell-material interactions (soft collagen gels in this case) can induce cellular phenotype and cytoskeleton organization in a remarkably distinct manner compared to a classical synthetic polyacrylamide (PA) hydrogel cell culture model and may contribute in designing new functional biomaterials. PMID:25284029

Ali, M Yakut; Chuang, Chih-Yuan; Saif, M Taher A

2014-10-23

193

New polymer gel dosimeters consisting of less toxic monomers with radiation-crosslinked gel matrix  

Science.gov (United States)

New polymer gel dosimeters consisting of less toxic methacrylate-type monomers such as 2-hydroxymethyl methacrylate (HEMA) and polyethylene glycol 400 dimethacrylate (9G) with hydroxypropyl cellulose (HPC) gel were prepared. The HPC gels were obtained by using a radiation-induced crosslinking technique to be applied in a matrix instead of a gelatin, which is conventionally used in earlier dosimeters, for the polymer gel dosimeters. The prepared polymer gel dosimeters showed cloudiness by exposing to 60Co ?-ray, in which the cloudiness increased with the dose up to 10 Gy. At the same dose, the increase in the cloudiness appeared with increasing concentration of 9G. As a result of the absorbance measurement, it was found that the dose response depended on the composition ratio between HEMA and 9G.

Hiroki, A.; Yamashita, S.; Sato, Y.; Nagasawa, N.; Taguchi, M.

2013-06-01

194

New polymer gel dosimeters consisting of less toxic monomers with radiation-crosslinked gel matrix  

International Nuclear Information System (INIS)

New polymer gel dosimeters consisting of less toxic methacrylate-type monomers such as 2-hydroxymethyl methacrylate (HEMA) and polyethylene glycol 400 dimethacrylate (9G) with hydroxypropyl cellulose (HPC) gel were prepared. The HPC gels were obtained by using a radiation-induced crosslinking technique to be applied in a matrix instead of a gelatin, which is conventionally used in earlier dosimeters, for the polymer gel dosimeters. The prepared polymer gel dosimeters showed cloudiness by exposing to 60Co ?-ray, in which the cloudiness increased with the dose up to 10 Gy. At the same dose, the increase in the cloudiness appeared with increasing concentration of 9G. As a result of the absorbance measurement, it was found that the dose response depended on the composition ratio between HEMA and 9G.

195

Effect of gamma radiation on silica gel  

International Nuclear Information System (INIS)

Silica gel degassed at elevated temperature (>4000C) forms color centers absorbing light at 320 and 530 m? upon ?-irradiation. Moreover, these gels adsorb H2 irreversibly. The color centers are readily bleached by H2. From the observed dependence on radiation dose and degassing temperature shown by the irradiated gel in respect of color center formation and H2 adsorption, the color centers - which have hitherto been tentatively attributed to positive holes - are now ascribed to the sites of the H2 adsorption. Assuming that one H2 molecule reacts with one positive hole, a G-value (positive hole) of about 0.3 is derived from the linear decrease of the color center at 530m? seen with increasing H2 adsorption. Inference from chemical behavior indicates the presence of trapped electrons on irradiated gel degassed above 4000C. When present during irradiation, electron scavengers such as N2O or SF6 promote the formation of the color center. A visual verification was conducted on the presence or absence of coloration undergone by irradiated gel upon exposure to each of sixteen different gaseous reagents. The results of this survey, referred to the known values of the ionization potential of these reagents, indicated the effective electron affinity of the positive hole to be in the vicinity of 11 eV. A mechanism is presented to explain some of the foregoing findings. (auth.)

196

Operation of a commercial solar gel pond  

Energy Technology Data Exchange (ETDEWEB)

The solar gel pond is an innovative concept which overcomes many of the shortcomings of the conventional salt-gradient solar pond. In this paper, the design, construction and start-up details of a commercial scale pond (400 m{sup 2}), built for a publishing company in Albuquerque, New Mexico will be presented. A pond with trapezoidal cross section was designed so that shadowing could be minimized and also the ratio of surface area to the volume of the storage zone could be maximized. The publishing company required a minimum of 1 GJ/day (1MBTU/day). Generally it has been noted that in ponds with large volume a lesser percentage of retained energy is lost as edge losses. Based on the above considerations a pond size of 400 m{sup 2} and 5 m deep with a gel thickness of 60 cm and a mass flow rate (for the heat extraction loop) of 1 {times} 10{sup {minus}4} to 1 {times} 10{sup {minus}3} kg/m{sup 2} {center dot} sec was determined to be the optimum size for the publishing company's needs. Two to seven percent salt water was used mainly to keep the gel bags floating on the surface. Tedlar bags were used to contain the gel. During the first year of operation, while the pond was still heating up, the pond obtained a temperature of 60C and the gel showed no signs of degradation.

Wilkens, E. (Univ. of New Mexico, Albuquerque (United States))

1991-01-01

197

Effectiveness of Gel Repellents on Feral Pigeons  

Directory of Open Access Journals (Sweden)

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.

Birte Stock

2013-12-01

198

PRONIOSOMAL GEL OF FLURBIPROFEN: FORMULATION AND EVALUATION  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this research is to design proniosomal gel drug delivery system of flurbiprofen in a trial to overcome the adverse effects associated with oral administration of the drug. This can be overcome by the use of vesicular drug delivery system. Encapsulation of a drug in vesicular structure can be predicted to prolong the existence of the drug in the systemic circulation and thus enhance penetration into target tissue and reduce toxicity. Proniosomal gels are generally present in transparent, translucent or white semisolid gel texture. Due to the limited solvent system present, the proniosomes formed were the mixture of many phases of liquid crystal, viz. lamellar, hexagonal and cubic phase liquid crystals. The potential of proniosomes as a transdermal drug delivery system for flurbiprofen was investigated by encapsulating the drug in various formulations of proniosomal gel composed of various ratios of sorbitan fatty acid esters, cholesterol, prepared by coacervation-phase separation method. The formulated systems were characterized in vitro for size, vesicle count, drug entrapment, drug release profiles and vesicular stability at different storage conditions. Stability studies for proniosomal gel were carried out for 4 weeks. The method of proniosome loading resulted in an encapsulation yield of 30.6 – 75.4%. Proniosomes were characterised by transmission electron microscopy. In vitro studies showed prolonged release of entrapped flurbiprofen. At refrigerated conditions, higher drug retention was observed. It is evident from this study that proniosomes are a promising prolonged delivery system for captopril and have reasonably good stability characteristics.

Sunil Kumar

2012-01-01

199

Gel-Filled Holders For Ultrasonic Transducers  

Science.gov (United States)

In new technique, ultrasonic transducer embedded in rubbery, castable, low-loss gel to enable transducer to "look" into surface of test object or human body at any desired angle. Composed of solution of water and ethylene glycol in collagen matrix. Provides total contact of water bath, also used on bodies or objects too large for water baths, even if moving. Also provides look angles of poly(methyl methacrylate) angle block with potential of reduced acoustic impedance and refraction. Custom-tailored to task at hand, and gel sufficiently inexpensive to be discarded upon completion. Easy to couple ultrasound in and out of gel, minimizing losses and artifacts of other types of standoffs employed in ultrasonic testing.

Companion, John A.

1992-01-01

200

Synthesis and characterization of aluminum carboxylate gels  

Energy Technology Data Exchange (ETDEWEB)

Aluminum formate and basic acetate gels obtained from commercial pseudoboehmite were synthesized in this work. Phase evolution after successive thermal treatments was studied on the raw material and both gels. In both carboxylates the influence of aging time on the composition, the crystalline structure and the phase transition temperatures was studied by X-ray diffraction (XRD) and differential thermal analysis (DTA) and thermogravimetric analysis (TGA). Two different stages were observed in the thermal decomposition of both carboxylates: the first, corresponding to the decarboxilation and dehydration of the gels, was different for both cases because of the different type of carboxilic acids used; and the second, corresponding to the formation of transition aluminas, was the same whatever the precursor used. However, whenever the aging time was changed on any of the carboxylates, the mechanisms of the thermal transformations were affected.

Clar, C.; Scian, A.N.; Aglietti, E.F

2003-12-05

 
 
 
 
201

Low-Reynolds number swimming in gels  

CERN Document Server

Many microorganisms swim through gels, materials with nonzero zero-frequency elastic shear modulus, such as mucus. Biological gels are typically heterogeneous, containing both a structural scaffold (network) and a fluid solvent. We analyze the swimming of an infinite sheet undergoing transverse traveling wave deformations in the "two-fluid" model of a gel, which treats the network and solvent as two coupled elastic and viscous continuum phases. We show that geometric nonlinearities must be incorporated to obtain physically meaningful results. We identify a transition between regimes where the network deforms to follow solvent flows and where the network is stationary. Swimming speeds can be enhanced relative to Newtonian fluids when the network is stationary. Compressibility effects can also enhance swimming velocities. Finally, microscopic details of sheet-network interactions influence the boundary conditions between the sheet and network. The nature of these boundary conditions significantly impacts swimmi...

Fu, Henry C; Powers, Thomas R

2010-01-01

202

Superconductive ceramics obtained with sol gel method  

International Nuclear Information System (INIS)

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

203

Lentivírus em caprinos leiteiros do semiárido paraibano: prevalência de anticorpos, fatores de risco e detecção molecular / Lentivirus in dairy goats from the semiarid region of Paraiba state: seroprevalence, risk factors and molecular detection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os objetivos do presente trabalho foram determinar a prevalência de caprinos leiteiros soropositivos para a infecção por Lentivirus de pequenos ruminantes no semiárido do Estado da Paraíba, Nordeste do Brasil, identificar fatores de risco associados à prevalência de rebanhos positivos, e realizar a [...] detecção molecular do agente. Foram utilizadas 1047 cabras leiteiras de 110 propriedades selecionadas aleatoriamente no Município de Monteiro, Estado da Paraíba, no período de março de 2009 a dezembro de 2011. Para o diagnóstico da infecção por Lentivirus, foi utilizado o teste de imunodifusão em gel de ágar (AGID). Um ano após foi realizada nova sorologia, e PCR em tempo real foi aplicada em amostras de sangue e leite de 48 cabras procedentes de quatro propriedades com animais soropositivos. As prevalências de propriedades positivas e de animais soropositivos na AGID foram 44,6% (IC 95% = 35,1% - 54,3%) e 8,1% (IC 95% = 5,6% - 16,8%), respectivamente. Realizar corte e desinfecção de umbigo (odds ratio = 2,44; p = 0,048) e condições de aglomeração de animais (odds ratio = 3,45; p = 0,048) foram associadas com a prevalência de propriedades positivas. Um ano após a realização do inquérito sorológico, foi verificada a permanência de animais infectados, detectados por PCR em tempo real a partir de amostras de sangue e leite. A PCR em tempo real das amostras de leucócitos circulantes apresentou boa performance, com sensibilidade de 100%, especificidade de 92,86%, concordância de 93,75% e indicador Kappa de 0,765. Sugere-se que seja realizado um trabalho de educação sanitária junto aos produtores sobre medidas de prevenção com o objetivo de reduzir a disseminação da infecção nos rebanhos. Abstract in english The aims of this study were to determine the seroprevalence of infection by ruminants Lentivirus in dairy goats in the semiarid of the Paraiba State, Northeastern Brazil, to identify risk factors associated with the herd-level prevalence and to perform molecular detection of the agent. A total of 1, [...] 047 dairy goats from 110 herds were randomly selected from the county of Monteiro, Paraiba State, and serum samples were collected from March 2009 to December 2011. For the diagnosis of Lentivirus infection, the agar gel immunodiffusion test (AGID) was used. One year after that a new serology was performed and the real-time PCR assay was applied in blood and milk samples from 48 goats from four herds with seropositive animals. Prevalence of positive herds and seropositive animals at AGID were 44.6% (95% CI=35.1-54.3%) and 8.1% (95% CI =5.6-16.8%), respectively. Umbilical cord cutting and disinfection (odds ratio = 2.44; p = 0.048) and conditions of animal agglomeration (odds ratio=3.45; p=0.048) were associated with herd-level prevalence. One year after the serological profile, the permanence of infected animals detected by real-time PCR in blood and milk samples was verified. Real-time PCR using white blood cells had a good performance, with sensitivity of 100%, specificity of 92.86%, concordance of 93.75% and Kappa index of 0.765. It was suggested to teach sanitary measures to the herd owners in order to encourage them to adopt prevention measures aiming to reduce the spread of the infection in the herds.

Maria L.C.R., Silva; Roberto S., Castro; Rita C., Maia; Sergio A., Nascimento; Ana Lisa V., Gomes; Sérgio S., Azevedo.

2013-04-01

204

Charge screening effects in charged gel  

International Nuclear Information System (INIS)

Structures of micro-phase separation are studied in the aqueous gel consisting of hydrophobic and hydrophilic monomers with charged groups. Small angle neutron scattering (SANS) measurements are applied for nano-scale structures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) gel with Na+ pair ions and N-isopropylacrylamide-acrylic acid (NIPA-AAc) gel with H+ pair ions. Structural size in micro-phase separation in aqueous gel is presumed to be dependent of the difference of hydrophilicity between hydrophilic and hydrophobic regions. Since hydrophilicity of charged groups is changed by electrolytic dissociation of themselves, screening of charges of charged groups in gel causes the change of electrolytic dissociation and hydrophilicity. Attention is paid for the structural change resulted from above change of electrolytic dissociation and hydrophilicity. The screening of charged groups depends on pair ions. Correlation between difference of the pair ions and nano-scale structures is measured by SANS. Water evaporates initially from the vicinity of high hydrophobic NIPA and condenses around the vicinity of high hydrophilic carboxy groups (CG). As the result of this, a phase separation is caused in the gel at this stage. Further dehydration reduces water around the vicinity of CG. At this stage, CG in the case of the H+ pair ions does not dissociate and the structure of the micro-phase separation annihilates. On the other hand, in case of the Na+ pair ions CG dissociates and the structure of the micro-phase separation is observed in a fairly progressive stage of dehydration. (Y. Kazumata)

205

Radiochromic gel dosemeter for three dimensional dosimetry  

International Nuclear Information System (INIS)

Conformal radiotherapy treatments require highly accurate three dimensional dose predictions for very intricate irradiation beam patterns applied to a complex target geometry, and there is a clear need for validating such dose computations over a range of typical geometries. Hence a dosimetric technique capable of accurate measurement of the spatial distribution, in three dimensions, of radiation dose in tissue equivalent materials is required. For this purpose several research groups have developed polymer gels with some success. However these materials are difficult to prepare and require relatively expensive and slow MRI or laser-based readout systems. These difficulties inspired the development of a simpler, more practical, dosemeter material suitable for three- dimensional dose measurements. This new dosemeter formulation is essentially a variant of the classic Fricke dosemeter and consists of ferrous ions in an acid environment plus a xylenol orange ion-indicator. Upon irradiation ferrous ions change to ferric by oxidation which causes the xylenol orange to turn purple. These changes in the optical density are spatially stabilised by means of a transparent gelatin gel. The optimal formulation of the ferrous xylenol gelatin (FXG) gel system for conformal radiotherapy planning has been established. The FXG dosemeter was characterised by comparison with both the standard Fricke solution and the older MRI Fricke gel method. Its dose response is linear over the range 0.1-30 Gy and its radiation chemical yield is an order of magnitude higher than the G-value of the standard Fricke dosemeter, and about three times higher than that of a ferrous xylenol solution. The stability and reproducibility were also studied and found to be adequate for the application envisaged. In addition, the new gel proved to be much simpler, quicker, and cheaper to prepare than polymer gels using normal laboratory facilities. FXG is highly transparent over optical wavelengths and can be rapidly read out using a broad beam optical tomographic imaging technique. (author)

206

Sol - gel development activities at IGCAR  

International Nuclear Information System (INIS)

A laboratory scale facility for fabrication of test fuel pins for irradiation in FBTR, Kalpakkam has been set up. These fuel pins will be vibropacked with sol-gel derived microspheres or stacked with pellets obtained by compaction of sol-derived microspheres. The facility is aimed at demonstration of the remotisation of the fuel pin fabrication process through sol-gel route. A capsule containing three test pins from this facility will be irradiated in FBTR from the end of 2009. The design features of the facility and the test fuel pins are described in this paper. (author)

207

Connectivity in sol-gel silica glasses  

Directory of Open Access Journals (Sweden)

Full Text Available In this work it is carried out a review on structural parameters related to the evaluation of pore connectivity of nanostructures. The work describes parameters and methods of evaluation of geometric parameters. The concepts of connectivity are applied to silica gels and glasses obtained from sol-gel process. The study of pores connectivity was carried out using a combination of geometric modeling and experimental evaluation of specific surface area and pore volume. The permeability of the pore structure is evaluated and a permeability geometric factor, Pg, is proposed.

Wander L. Vasconcelos

1998-07-01

208

Mixed iota-kappa carrageenan gels.  

Science.gov (United States)

Studies have been made of the gelation of mixtures of iota and kappa carrageenan. Differential scanning calorimetry (DSC) studies suggest that the iota and kappa components gel independently of each other. The DSC data conflict with evidence presented for the currently accepted Domain model for carrageenan gelation (Morris, E.R., Rees, D.A. and Robinson, G.J. J. Mol. Biol. 1980; 138:349). In particular, the present data suggest that iota carrageenan gels show thermoreversible setting and melting behaviour associated with the coil-helix transition. Analysis of rheological data favours an interpenetrating network (IPN) model for gelation of the mixtures. PMID:8852747

Ridout, M J; Garza, S; Brownsey, G J; Morris, V J

1996-02-01

209

Neutron detector using sol-gel absorber  

International Nuclear Information System (INIS)

An neutron detector composed of fissionable material having ions of lithium, uranium, thorium, plutonium, or neptunium, contained within a glass film fabricated using a sol-gel method combined with a particle detector is disclosed. When the glass film is bombarded with neutrons, the fissionable material emits fission particles and electrons. Prompt emitting activated elements yielding a high energy electron contained within a sol-gel glass film in combination with a particle detector is also disclosed. The emissions resulting from neutron bombardment can then be detected using standard UV and particle detection methods well known in the art, such as microchannel plates, channeltrons, and silicon avalanche photodiodes

210

Sol-gel synthesis of orthosilicates ????-???? ?????? ?????????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of the research is the sol-gel preparation of the crystalline or amorphous orthosilicates of some bivalent metals, namely, copper orthosilicate (Cu2SiO4), which seems to be a quite efficient catalyst, although it has not been synthesized yet. The main obstacles that prevent the sol-gel synthesis of orthosilicates include high metal/silica molar ratios in precursor mixtures. They cause (i) formation of the crystalline of metal oxides at intermediate stages of synthesis and (ii) a...

Malyavskiy Nikolay Ivanovich; Pokidko Boris Vladimirovich

2012-01-01

211

Elasticity of entangled polymer loops: Olympic gels  

International Nuclear Information System (INIS)

In this Rapid Communication we present a scaling theory for the elasticity of olympic gels, i.e., gels where the elasticity is a consequence of topology only. It is shown that two deformation regimes exist. The first is the nonaffine deformation regime where the free energy scales linear with the deformation. In the large (affine) deformation regime the free energy is shown to scale as F??5/2 where ? is the deformation ratio. Thus a highly non-Hookian stress-strain relation is predicted. copyright 1997 The American Physical Society

212

Effective Management of FXG Gel Dosimetry  

International Nuclear Information System (INIS)

The details of a calibration basis for the Fricke-xylenol orange-gelatin (FXG) gel dosimeter combined with the fast, easily accessible readout tool of cone beam optical computed tomography (CT) are described in this report. With proper controls in place, the results from a test intensity modulated radiation therapy (IMRT) treatment plan evaluation indicate that greater than 95% Low's gamma function agreement between plan and gel-measured dose using 3% dose and 3 mm distance-to-agreement criteria is achievable.

213

Effective Management of FXG Gel Dosimetry  

Energy Technology Data Exchange (ETDEWEB)

The details of a calibration basis for the Fricke-xylenol orange-gelatin (FXG) gel dosimeter combined with the fast, easily accessible readout tool of cone beam optical computed tomography (CT) are described in this report. With proper controls in place, the results from a test intensity modulated radiation therapy (IMRT) treatment plan evaluation indicate that greater than 95% Low's gamma function agreement between plan and gel-measured dose using 3% dose and 3 mm distance-to-agreement criteria is achievable.

Olding, T; Darko, J; Schreiner, L J, E-mail: Tim.Olding@krcc.on.c

2010-11-01

214

Effective Management of FXG Gel Dosimetry  

Science.gov (United States)

The details of a calibration basis for the Fricke-xylenol orange-gelatin (FXG) gel dosimeter combined with the fast, easily accessible readout tool of cone beam optical computed tomography (CT) are described in this report. With proper controls in place, the results from a test intensity modulated radiation therapy (IMRT) treatment plan evaluation indicate that greater than 95% Low's gamma function agreement between plan and gel-measured dose using 3% dose and 3 mm distance-to-agreement criteria is achievable.

Olding, T.; Darko, J.; Schreiner, L. J.

2010-11-01

215

Produção e padronização dos antígenos de Paracoccidioides brasiliensis (Pb, Histoplasma capsulatum (Hc e Aspergillus fumigatus (Af para uso no imunodiagnóstico: comparação entre as técnicas de imunodifusão e imunoeletroosmoforese Production and standardization of Paracoccidioides brasiliensis, Histoplasm capsulatum and Aspergillus fumigatus antigens to be used in immunodiagnosis: comparison between immunodiffusion and immunoelectrophoresis technics  

Directory of Open Access Journals (Sweden)

Full Text Available Foram produzidos antígenos solúveis de P. brasiliensis, H. capsulatum e A. fumigatus e padronizados nas técnicas de imunodifusão dupla (IDD e imunoeletroosmoforese (IEOF. A especificidade dos antígenos foi testada utilizando-se 96 soros de pacientes com paracoccidioidomicose, histoplasmose, aspergilose, candidíase sistêmica, esporotricose, tuberculose, neoplasia pulmonar, leishmaniose tegumentar e visceral e em 18 indivíduos sadios. Na IDD, a especificidade foi de 100% usando-se como critério de positividade linhas de precipitação com identidade total com soro de referência. Entretanto na IEOF, a especificidade variou de acordo com o antígeno testado, sendo observadas reações cruzadas com antígeno de P. brasiliensis frente a soros de pacientes com histoplasmose (16,7% e leishmaniose tegumentar (10% e com antígeno de H. capsulatum frente a soros de pacientes com paracoccidioidomicose (31,8% e leishmaniose tegumentar (10%. Ambas as técnicas mostraram a mesma sensibilidade para o sorodiagnóstico de paracoccidioidomicose, histoplasmose e aspergilose, respectivamente 100%, 83,3% e 100%. A grande sensibilidade e especificidade da IDD observadas nos soros desses pacientes, aliadas à fácil reprodutibilidade e baixo custo, fazem esta técnica muito apropriada como procedimento de rotina, para a triagem de pacientes sintomáticos respiratórios.Soluble antigens (Ag from Paracoccidioides brasiliensis, Histoplasma capsulatum and Aspergillus fumigatus were prepared and standardized by double immunodiffusion (DID and immunoelectroosmophoresis (IEOP. No difference in sensitivity was observed between the two techniques; 100% of standard patient sera were positive with P. brasiliensis and A. fumigatus Ag and 83.3% were positive with H. capsulatum Ag. The specificity of the tests was verified testing 96 sera from patients with paracoccidioidomycosis, histoplasmosis, systemic candidiasis, sporotrichosis, tuberculosis, lung cancer, visceral or cutaneous leishmaniasis and 18 sera from healthy individuals. All the three antigens were 100% specific with the DID (using the identification pattern indicated by the confluence of test serum with standard serum precipitin lines as a positive criterium. However in the IEOP, the specificity varied with each Ag. Positive reactions with P. brasiliensis Ag were observed in 16.7% of histoplasmosis sera and in 10% of cutaneous leishmaniasis sera. On the other hand 31.8% of paracoccidioidomycosis and 10% of cutaneous leishmaniasis sera reacted with H. capsulatum Ag. The high sensitivity and specificity of the DID test, its easy reproducibility and low cost, led us to consider it highly appropriate as a routine procedure for the screening of patients with respiratory infections.

Maria de Fátima Ferreira-da-Cruz

1985-09-01

216

Produção e padronização dos antígenos de Paracoccidioides brasiliensis (Pb), Histoplasma capsulatum (Hc) e Aspergillus fumigatus (Af) para uso no imunodiagnóstico: comparação entre as técnicas de imunodifusão e imunoeletroosmoforese / Production and standardization of Paracoccidioides brasiliensis, Histoplasm capsulatum and Aspergillus fumigatus antigens to be used in immunodiagnosis: comparison between immunodiffusion and immunoelectrophoresis technics  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foram produzidos antígenos solúveis de P. brasiliensis, H. capsulatum e A. fumigatus e padronizados nas técnicas de imunodifusão dupla (IDD) e imunoeletroosmoforese (IEOF). A especificidade dos antígenos foi testada utilizando-se 96 soros de pacientes com paracoccidioidomicose, histoplasmose, asperg [...] ilose, candidíase sistêmica, esporotricose, tuberculose, neoplasia pulmonar, leishmaniose tegumentar e visceral e em 18 indivíduos sadios. Na IDD, a especificidade foi de 100% usando-se como critério de positividade linhas de precipitação com identidade total com soro de referência. Entretanto na IEOF, a especificidade variou de acordo com o antígeno testado, sendo observadas reações cruzadas com antígeno de P. brasiliensis frente a soros de pacientes com histoplasmose (16,7%) e leishmaniose tegumentar (10%) e com antígeno de H. capsulatum frente a soros de pacientes com paracoccidioidomicose (31,8%) e leishmaniose tegumentar (10%). Ambas as técnicas mostraram a mesma sensibilidade para o sorodiagnóstico de paracoccidioidomicose, histoplasmose e aspergilose, respectivamente 100%, 83,3% e 100%. A grande sensibilidade e especificidade da IDD observadas nos soros desses pacientes, aliadas à fácil reprodutibilidade e baixo custo, fazem esta técnica muito apropriada como procedimento de rotina, para a triagem de pacientes sintomáticos respiratórios. Abstract in english Soluble antigens (Ag) from Paracoccidioides brasiliensis, Histoplasma capsulatum and Aspergillus fumigatus were prepared and standardized by double immunodiffusion (DID) and immunoelectroosmophoresis (IEOP). No difference in sensitivity was observed between the two techniques; 100% of standard patie [...] nt sera were positive with P. brasiliensis and A. fumigatus Ag and 83.3% were positive with H. capsulatum Ag. The specificity of the tests was verified testing 96 sera from patients with paracoccidioidomycosis, histoplasmosis, systemic candidiasis, sporotrichosis, tuberculosis, lung cancer, visceral or cutaneous leishmaniasis and 18 sera from healthy individuals. All the three antigens were 100% specific with the DID (using the identification pattern indicated by the confluence of test serum with standard serum precipitin lines as a positive criterium). However in the IEOP, the specificity varied with each Ag. Positive reactions with P. brasiliensis Ag were observed in 16.7% of histoplasmosis sera and in 10% of cutaneous leishmaniasis sera. On the other hand 31.8% of paracoccidioidomycosis and 10% of cutaneous leishmaniasis sera reacted with H. capsulatum Ag. The high sensitivity and specificity of the DID test, its easy reproducibility and low cost, led us to consider it highly appropriate as a routine procedure for the screening of patients with respiratory infections.

Maria de Fátima, Ferreira-da-Cruz; Bernardo, Galvão-Castro; Bodo, Wanke.

217

Produção e padronização dos antígenos de Paracoccidioides brasiliensis (Pb), Histoplasma capsulatum (Hc) e Aspergillus fumigatus (Af) para uso no imunodiagnóstico: comparação entre as técnicas de imunodifusão e imunoeletroosmoforese / Production and standardization of Paracoccidioides brasiliensis, Histoplasm capsulatum and Aspergillus fumigatus antigens to be used in immunodiagnosis: comparison between immunodiffusion and immunoelectrophoresis technics  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foram produzidos antígenos solúveis de P. brasiliensis, H. capsulatum e A. fumigatus e padronizados nas técnicas de imunodifusão dupla (IDD) e imunoeletroosmoforese (IEOF). A especificidade dos antígenos foi testada utilizando-se 96 soros de pacientes com paracoccidioidomicose, histoplasmose, asperg [...] ilose, candidíase sistêmica, esporotricose, tuberculose, neoplasia pulmonar, leishmaniose tegumentar e visceral e em 18 indivíduos sadios. Na IDD, a especificidade foi de 100% usando-se como critério de positividade linhas de precipitação com identidade total com soro de referência. Entretanto na IEOF, a especificidade variou de acordo com o antígeno testado, sendo observadas reações cruzadas com antígeno de P. brasiliensis frente a soros de pacientes com histoplasmose (16,7%) e leishmaniose tegumentar (10%) e com antígeno de H. capsulatum frente a soros de pacientes com paracoccidioidomicose (31,8%) e leishmaniose tegumentar (10%). Ambas as técnicas mostraram a mesma sensibilidade para o sorodiagnóstico de paracoccidioidomicose, histoplasmose e aspergilose, respectivamente 100%, 83,3% e 100%. A grande sensibilidade e especificidade da IDD observadas nos soros desses pacientes, aliadas à fácil reprodutibilidade e baixo custo, fazem esta técnica muito apropriada como procedimento de rotina, para a triagem de pacientes sintomáticos respiratórios. Abstract in english Soluble antigens (Ag) from Paracoccidioides brasiliensis, Histoplasma capsulatum and Aspergillus fumigatus were prepared and standardized by double immunodiffusion (DID) and immunoelectroosmophoresis (IEOP). No difference in sensitivity was observed between the two techniques; 100% of standard patie [...] nt sera were positive with P. brasiliensis and A. fumigatus Ag and 83.3% were positive with H. capsulatum Ag. The specificity of the tests was verified testing 96 sera from patients with paracoccidioidomycosis, histoplasmosis, systemic candidiasis, sporotrichosis, tuberculosis, lung cancer, visceral or cutaneous leishmaniasis and 18 sera from healthy individuals. All the three antigens were 100% specific with the DID (using the identification pattern indicated by the confluence of test serum with standard serum precipitin lines as a positive criterium). However in the IEOP, the specificity varied with each Ag. Positive reactions with P. brasiliensis Ag were observed in 16.7% of histoplasmosis sera and in 10% of cutaneous leishmaniasis sera. On the other hand 31.8% of paracoccidioidomycosis and 10% of cutaneous leishmaniasis sera reacted with H. capsulatum Ag. The high sensitivity and specificity of the DID test, its easy reproducibility and low cost, led us to consider it highly appropriate as a routine procedure for the screening of patients with respiratory infections.

Maria de Fátima, Ferreira-da-Cruz; Bernardo, Galvão-Castro; Bodo, Wanke.

1985-09-01

218

The mechanism and properties of acid-coagulated milk gels  

Directory of Open Access Journals (Sweden)

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.

Chanokphat Phadungath

2005-03-01

219

Sol-gel additive for systems with inorganic binders  

International Nuclear Information System (INIS)

A sol-gel additive for inorganic binder systems and sol-gel process for producing air-placed concrete and mortar by using such sol-gel additives are disclosed. Sol-gel additives for gel-derived inorganic binder systems (for example plaster, cement, lime, special slags, etc.) marked improve the consistency of such binder systems during processing or allow their consistency to be regulated. In addition, these sol-gel additives regulate setting times and substantially improve durability (chemical resistance, reduced permeability) and the mechanical properties of the set binder system. (author)

220

Sol-gel additive for systems with inorganic binders  

Energy Technology Data Exchange (ETDEWEB)

A sol-gel additive for inorganic binder systems and sol-gel process for producing air-placed concrete and mortar by using such sol-gel additives are disclosed. Sol-gel additives for gel-derived inorganic binder systems (for example plaster, cement, lime, special slags, etc.) marked improve the consistency of such binder systems during processing or allow their consistency to be regulated. In addition, these sol-gel additives regulate setting times and substantially improve durability (chemical resistance, reduced permeability) and the mechanical properties of the set binder system. (author).

Akstinat, M.; Antenen, D.; Suter, W.

1996-05-17

 
 
 
 
221

Multiple-phase behavior and memory effect of polymer gel  

International Nuclear Information System (INIS)

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.)

222

Elastic interactions in nematic elastomers and gels  

Science.gov (United States)

We investigate elastic interactions in nematic elastomers and gels using a Ginzburg-Landau model for the isotropic-nematic transition. We propose an elastic origin of the "four-leaf clover" pattern observed in depolarised light scattering from polydomain nematic elastomers. We also investigate the director fluctuation in the nematic phase. Aligned nematic states are found to be unstable below a critical elongation.

Uchida, N.; Onuki, A.

1999-02-01

223

Staining and Imaging an Agarose Gel  

Science.gov (United States)

This video from CUNY Kingsborough Community College shows the process of staining and imaging an agarose gel. The video describes the process step by step and would be easy to replicate in a laboratory setting. Running time for the video is 3:18.

Hinkley, Craig

2013-06-20

224

The Genetic Science Learning Center: Gel Electrophoresis  

Science.gov (United States)

Gel Electrophoresis, designed and run by the University of Utah, is an interactive program that allows the student to learn and practice basic techniques that molecular biologists use every day. This program is an interactive animated procedure that allows the user to "see" DNA strands and instructs the student or user on the basics of DNA.

2007-04-05

225

Simple Cloud Chambers Using Gel Ice Packs  

Science.gov (United States)

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…

Kamata, Masahiro; Kubota, Miki

2012-01-01

226

Preparation for Pouring an Agarose Gel  

Science.gov (United States)

This video from CUNY Kingsborough Community College describes the technique of preparing to pour an Agarose Gel. The video describes the process step by step and would be easy to replicate in a laboratory setting. Running time for the video is 3:22.

Hinkley, Craig

2013-06-25

227

Mechanical properties and morphology of polymer gels  

Science.gov (United States)

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.

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

2012-02-01

228

Gel Filtration Chromatography: A Laboratory Experiment.  

Science.gov (United States)

Describes a rapid, visual demonstration of protein separation by gel filtration chromatography. The procedure separates two highly colored proteins of different molecular weights on a Sephadex G-75 in 45 minutes. This time includes packing the column as well. Background information, reagents needed, procedures used, and results obtained are…

Hurlbut, Jeffrey A.; Schonbeck, Niels D.

1984-01-01

229

Electrochemical Growth Of Crystals In Gels  

Science.gov (United States)

Nucleation and growth rates readily controlled. Technique developed to grow crystals by controlling rate of transfer of one component into crystallization volume. Method involves electrochemically controlled generation of one of precipitation species, coupled with diffusion barrier. New procedure, developed in connection with formation of lead tin telluride by reaction in gels of metal ions with telluride ions.

Barber, Patrick G.; Coleman, James

1988-01-01

230

Gel electrophoresis of intact subcellular particles.  

Science.gov (United States)

The review describes the application of gel electrophoresis to the characterization and separation of viruses, ribosomes, vesicles and other subcellular particles. The preparation of the sample, the choice of the buffer, the gel medium, the apparatus and the detection of the particle (staining and scanning) as well as the necessary theory are discussed. This includes the mathematical evaluation of experimental data on the basis of Ferguson plots using the extended Ogston theory. Simple methods and sophisticated computer simulation techniques are described and exemplified in application to the determination of particle size and charge, the pore size of the gel (unpublished data) and the two-dimensional agarose electrophoresis (unpublished). It is shown that the nature of the particle (e.g. spherical or rod-shaped, pliable or rigid texture) determines the shape of the non-linear Ferguson plot. In addition, the review gives a number of practical applications of gel electrophoresis, isoelectric focusing, titration curves and immuno-electrophoresis to subcellular particles. Pros and cons are evaluated. A comparison with other analytical procedures is made. The review is concluded by a futuristic outlook. PMID:3305546

Tietz, D

1987-07-17

231

Thermal Decomposition Characteristics of ADU Gel Spheres  

Energy Technology Data Exchange (ETDEWEB)

HTGR nuclear fuel uses a modified sol.gel GSP (Gel Supported Precipitation) method, which is a wet method used in most countries. ADU(Ammonium DiUranate) gel particles fabricated in this way pass through thermal treatments and become final UO{sub 2} microspheres. The washing characteristics such as washing volume, duration, and times during AWD(ageing, washing and drying) process after the spherical ADU gel particles preparation by the GSP method was studied. The VHTR (Very High Temperature Gas Reactor) is one of the reactor concepts in the Gen IV International Collaboration. Unlike light water reactor currently in use in Korea, a HTGR actually functions as a gas cooled reactor where the high temperature heat generated from nuclear fission in a reactor is cooled by He gas, with uranium dioxide (UO{sub 2} is globally used) used as fuel for the nuclear fission. Generally, nuclear fuel used in a HTGR is fabricated into a TRISO (TRi.ISOtropic) structure that can prevent the leakage of nuclear fission products at high temperatures.

Jeong, Kyung Chai; Eom, Sung Ho; Kim, Yeon Ku; Kim, Young Min; Kim, Woong Ki; Kim, Bong Ku; Lee, Young Woo; Cho, Moon Seoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

232

Das Sol-Gel-Verfahren : anorganische Synthesemethoden  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Was haben kratzfeste Beschichtungen von Kunststoffgläsern für Brillen gemeinsam mit Hologrammen? Das Stichwort heißt Sol-Gel-Prozess: Die Synthesemethode ist eine Basis für die chemische Nanotechnologie und findet zahlreiche Anwendungen in der Beschichtung von Oberflächen aber auch für die optische Datenspeicherung.

Schmidt, Helmut K.

2001-01-01

233

Bioactive nanocrystalline sol-gel hydroxyapatite coatings.  

Science.gov (United States)

Sol-gel technology offers an alternative technique for producing bioactive surfaces for improved bone attachment. Previous work indicated that monophasic hydroxyapatite coatings were difficult to produce. In the present work hydroxyapatite was synthesized using the sol-gel technique with alkoxide precursors and the solution was allowed to age up to seven days prior to coating. It was found that, similar to the wet-chemical method of hydroxyapatite powder synthesis, an aging time is required to produce a pure hydroxyapatite phase. A methodology that has been successfully used to produce nanocrystalline hydroxyapatite thin film coatings via the sol-gel route on various substrates including alumina, Vycor glass, partially stabilized zirconia, Ti-6Al-4V alloy and single crystal MgO is described. Coatings produced on MgO substrates were characterized by X-ray diffraction and atomic force microscopy, while the analogous gels were examined with thermogravimetric and differential thermal analyses. The coatings were crack free and the surface was covered with small grains, of approximately 200 nm in size for samples fired to 1000 degrees C. Coating thickness varied between 70 and 1000 nm depending on the number of applied layers. PMID:15348113

Chai, C S; Ben-Nissan, B

1999-08-01

234

Electrophoretic Porosimetry of Sol-Gels  

Science.gov (United States)

It has been hypothesized that gravity has an effect on the formation and resulting microstructure of sol-gels. In order to more clearly resolve the effect of gravity, pores may be non-destructively analyzed in the wet gel, circumventing the shrinkage and coarsening associated with the drying procedure. We discuss the development of an electrophoretic technique, analogous to affinity chromatography, for the determination of pore size distribution and its application to silica gels. Specifically a monodisperse charged dye is monitored by an optical densitometer as it moves through the wet gel under the influence of an electric field. The transmittance data (output) represents the convolution of the dye concentration profile at the beginning of the run (input) with the pore size distribution (transfer function), i.e. linear systems theory applies. Because of the practical difficulty in producing a delta function input dye profile we prefer instead to use a step function. Average pore size is then related to the velocity of this dye front, while the pore size distribution is related to the spreading of the front. Preliminary results of this electrophoretic porosimetry and its application to ground and space-grown samples will be discussed.

Snow, L. A.; Smith, D. D.; Sibille, L.; Hunt, A. J.; Ng, J.; Rose, M. Franklin (Technical Monitor)

2000-01-01

235

Optimization of topical gels with betamethasone dipropionate: selection of gel forming and optimal cosolvent system.  

Science.gov (United States)

The purpose of these studies was to develop a 0.05% betamethasone gel characterized by physical-chemical stability and good release properties. The preliminary studies were designed to select the gel-forming agents and the excipients compatible with betamethasone dipropionate. In order to formulate a clear gel without particles of drug substances in suspension, a solvent system for the drug substance was selected. The content of drug substance released, the rheological and in vitro release tests were the tools used for the optimal formulation selection. A stable carbomer gel was obtained by solubilization of betamethasone dipropionate in a vehicle composed by 40% PEG 400, 10% ethanol and 5% Transcutol. PMID:21870764

B?i?an, Mariana; Lionte, Mihaela; Moisuc, L?cr?mioara; Gafi?anu, Eliza

2011-01-01

236

Performance characteristics of AGM and gel batteries; Unterschiedliche Betriebseigenschaften von AGM- und Gel-Batterien  

Energy Technology Data Exchange (ETDEWEB)

The different electrolyte fixing of VRLA-batteries with absorbed glass mat (AGM) or with pyrogenic silica (GEL) has a remarkable influence in the operational characteristics of those batteries. Here is shown, that the cyclebility, the deep discharge stability, the resistance against thermal runaway and the stability of the capacity over life are better for GEL-batteries. AGM have due to their low internal resistance and lower costs advantages for low cost UPS-batteries. (orig.) [German] Die unterschiedliche Elektrolytfestlegung verschlossener Batterien in Glasfaservlies (AGM) oder mit pyrogener Kieselsaeure (GEL) hat einen erheblichen Einfluss auf die Betriebseigenschaften. In der folgenden Ausarbeitung wird gezeigt, dass GEL-Batterien in Bezug auf die Zyklenfestigkeit, die Tiefentladefestigkeit, der thermischen Belastbarkeit und der Stabilitaet der Kapazitaet ueber die Lebensdauer vorteilhafter sind als AGM-Batterien. AGM-Batterien haben wegen ihres geringen Widerstandes und ihrer geringeren Kosten Vorteile bei low-cost USV-Anlagen. (orig.)

Rusch, W. [BAE Berliner Batteriefabrik GmbH, Berlin (Germany)

1999-07-01

237

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

238

21 CFR 872.1730 - Electrode gel for pulp testers.  

Science.gov (United States)

... false Electrode gel for pulp testers. 872.1730 Section 872.1730 Food and Drugs FOOD AND DRUG ADMINISTRATION...DEVICES DENTAL DEVICES Diagnostic Devices § 872.1730 Electrode gel for pulp testers. (a)...

2010-04-01

239

21 CFR 872.1730 - Electrode gel for pulp testers.  

Science.gov (United States)

...2010-04-01 false Electrode gel for pulp testers. 872.1730 Section 872.1730 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1730 Electrode gel for pulp testers. (a)...

2010-04-01

240

Continuous alumina gel fibers by sol-gel method using glycolic acid, aluminum nitrate and polyvinylpyrrolidone  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Continuous alumina fibers were prepared by sol-gel method. The spinning sol was obtained by mixing aluminum nitrate, glycolic acid and polyvinylpyrrolidone with a weight ratio of 10:3:1.5. 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 fibers. The fibers with a uniform diameter and smooth surface were obtained by sintering at 1473K, and its main phase was indentified as ...

Hongbin Tan; Jianhua Zhang; Haiwa Bo

2011-01-01

 
 
 
 
241

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 in...

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

2013-01-01

242

Gel-expanded to gel-condensed transition in neurofilament networks revealed by direct force measurements  

Science.gov (United States)

Neurofilaments (NF)-the principal cytoskeletal constituent of myelinated axons in vertebrates-consist of three molecular-weight subunit proteins NF-L (low), NF-M (medium) and NF-H (high), assembled to form mature filaments with protruding unstructured C-terminus side arms. Liquid-crystal gel networks of side-arm-mediated neurofilament assemblies have a key role in the mechanical stability of neuronal processes. Disruptions of the neurofilament network, owing to neurofilament over-accumulation or incorrect side-arm interactions, are a hallmark of motor-neuron diseases including amyotrophic lateral sclerosis. Using synchrotron X-ray scattering, we report on a direct measurement of forces in reconstituted neurofilament gels under osmotic pressure (P). With increasing pressure near physiological salt and average phosphorylation conditions, NF-LMH, comprising the three subunits near in vivo composition, or NF-LH gels, undergo for P>Pc~10kPa, an abrupt non-reversible gel-expanded to gel-condensed transition. The transition indicates side-arm-mediated attractions between neurofilaments consistent with an electrostatic model of interpenetrating chains. In contrast, NF-LM gels remain in a collapsed state for PPc. These findings, which delineate the distinct roles of NF-M and NF-H in regulating neurofilament interactions, shed light on possible mechanisms for disruptions of optimal mechanical network properties.

Beck, Roy; Deek, Joanna; Jones, Jayna B.; Safinya, Cyrus R.

2010-01-01

243

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

International Nuclear Information System (INIS)

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

244

Gel-forming reagents and uses thereof for preparing microarrays  

Science.gov (United States)

New gel-forming reagents including monomers and cross-linkers, which can be applied to gel-drop microarray manufacturing by using co-polymerization approaches are disclosed. Compositions for the preparation of co-polymerization mixtures with new gel-forming monomers and cross-linker reagents are described herein. New co-polymerization compositions and cross-linkers with variable length linker groups between unsaturated C.dbd.C bonds that participate in the formation of gel networks are disclosed.

Golova, Julia (Burr Ridge, IL); Chernov, Boris (Burr Ridge, IL); Perov, Alexander (Woodridge, IL)

2010-11-09

245

The mechanism and properties of acid-coagulated milk gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Chanokphat Phadungath

2005-01-01

246

Relationship between texture of gels and flavour release  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Koliandris, Andreas

2009-01-01

247

Improvements in or relating to the drying of gel materials  

International Nuclear Information System (INIS)

A process is described for the drying of a gel material, comprising mixing together steam and gas in controlled amounts to form a mixture, feeding the mixture to a gel material to be dried thereby to contact the gel material with an atmosphere containing steam and gas in controlled amounts and thereby dry the gel material. One application of the process is in the production of ceramic particles for nuclear fuels. (author)

248

Formulation and method for preparing gels comprising hydrous cerium oxide  

Science.gov (United States)

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

Collins, Jack L; Chi, Anthony

2013-05-07

249

Stability of the gel formed during nuclear glass alteration  

International Nuclear Information System (INIS)

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)

250

Spherulitic Growth of Neodymium Tartrate Crystals in Silica Gel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Neodymium tartrate crystals in the form of spherulites were synthesized by using a controlled diffusion system in silica gel at ambient temperature. The influence of growth parameters e.g. reactant concentration, gel pH, gel ageing, on the size and nucleation density of the crystals ha...

Jayashree Hiralal Patil; Dilip Kashinath Sawant; Hiralal Motilal Patil; Bhavsar, Deelip S.

2010-01-01

251

21 CFR 520.1242f - Levamisole hydrochloride gel.  

Science.gov (United States)

...2010-04-01 false Levamisole hydrochloride gel. 520.1242f Section 520.1242f Food and...DRUGS § 520.1242f Levamisole hydrochloride gel. (a) Specifications. The drug is a gel containing 11.5 percent levamisole...

2010-04-01

252

21 CFR 872.1730 - Electrode gel for pulp testers.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Electrode gel for pulp testers. 872.1730 Section...Diagnostic Devices § 872.1730 Electrode gel for pulp testers. (a) Identification. An electrode gel for pulp testers is a device intended...

2010-04-01

253

21 CFR 520.1720d - Phenylbutazone gel.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Phenylbutazone gel. 520.1720d Section 520.1720d Food...ANIMAL DRUGS § 520.1720d Phenylbutazone gel. (a) Specifications. Each 30 grams of gel contains 4 grams of phenylbutazone....

2010-04-01

254

21 CFR 520.1242f - Levamisole hydrochloride gel.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Levamisole hydrochloride gel. 520.1242f ...FORM NEW ANIMAL DRUGS § 520.1242f Levamisole hydrochloride gel. (a) Specifications...drug is a gel containing 11.5 percent levamisole hydrochloride. (b) Sponsor....

2010-04-01

255

Formulation and method for preparing gels comprising hydrous hafnium oxide  

Science.gov (United States)

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

Collins, Jack L; Hunt, Rodney D; Montgomery, Frederick C

2013-08-06

256

Nanoscale Silicon Dioxide Prepared by Sol-Gel Process  

Directory of Open Access Journals (Sweden)

Full Text Available Nanoscale silicon dioxide has been prepared with tetraethyl orthosilicate (TEOS by sol-gel process. The optimum process conditions have been obtained by investigating the effect of formulation, temperature, catalyst and etc. on its gel morphology, gel time, and particle size.

Hui Gao

2010-08-01

257

Formulation and method for preparing gels comprising hydrous aluminum oxide  

Energy Technology Data Exchange (ETDEWEB)

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.

Collins, Jack L.

2014-06-17

258

Soroprevalência da infecção pelo vírus da artrite-encefalite caprina (caev) no rebanho de caprinos leiteiros da região da Grande Fortaleza, Ceará, Brasil / Seroprevalence of the caprine arthritis-encephalitis vírus infection in dairy goats in the region of "Grande Fortaleza", Ceará, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foi realizada uma pesquisa sorológica, com base no teste de imunodifusão em ágar gel (AGID) com antígeno (p28) do vírus Maedi/Visna, para estimar a soroprevalência da infecção pelo vírus da Artrite-Encefalite Caprina (CAEV) na população de caprinos leiteiros da região da Grande Fortaleza, Ceará. O e [...] studo abrangeu um total de oito criatórios. dos quais cinco praticam o manejo intensivo e três o manejo semi-intensivo. A população estudada é composta, por animais puros de raças exóticas como a Saanen, Parda Alpina, Anglonubiana e Toggenburg, por animais Meio Sangue e alguns sem raça definida (SRD). Foi realizado exame clinico e coleta de amostra de soro em 248 caprinos, bem como a aplicação de questinonário epidemiológico. A análise dos dados revelou uma soroprevalência de 40,73% (101/248). As amostras soropositivas foram todas provenientes das propriedades com manejo intensivo (5/8). A distribuição da soroprevalência em cada um destes criatórios foi 61% (54/89), 74,28% (26/35), 61,11% (11/18), 11,36% (5/44) e 75% (6/8). Diferença significativa (P0,05) quanto aos falares idade e sexo dos animais estudados. Abstract in english A serologic survey was performed using a agar gel immunodiffusion test (AGID) with the Maedi/Visna virus antigen (p28) to estimate the seroprevalence of the caprine arthritisencephalitis virus infection (CAEV) in a dairy goat population in the region of "Grande Fortaleza", in the state of Ceará, Bra [...] zil. In this study a total of eight flocks were examined, five included intensive and three semi-intensive managements. The population studied consisted of three groups: pure-bred animais of exotic races such as Saanen, Alpine Parda, Anglonubian and Toggenburg: crossbreeds and animais of undefined breed. Serum samples were colleted from 248 goats, clinicai analysis were performed, andan epidemiologic survey was applied. Analysis of the results showed a seroprevalence of 40.73% (101/248). All seropositive samples carne from the flocks with intensive management (5/8). The distribution of seroprevalence in each of these flocks was 61% (54/89). 74.28% (26/35), 61.11% (11/18), 11.36% (5/44) and 75% (6/8). A significam difference (P0.05) were observed related to age and sex of the studied animais.

Ana Célia Mendes, Melo; Carlos Roberto, Franke.

1997-03-01

259

Soroprevalência da infecção pelo vírus da artrite-encefalite caprina (caev no rebanho de caprinos leiteiros da região da Grande Fortaleza, Ceará, Brasil Seroprevalence of the caprine arthritis-encephalitis vírus infection in dairy goats in the region of "Grande Fortaleza", Ceará, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Foi realizada uma pesquisa sorológica, com base no teste de imunodifusão em ágar gel (AGID com antígeno (p28 do vírus Maedi/Visna, para estimar a soroprevalência da infecção pelo vírus da Artrite-Encefalite Caprina (CAEV na população de caprinos leiteiros da região da Grande Fortaleza, Ceará. O estudo abrangeu um total de oito criatórios. dos quais cinco praticam o manejo intensivo e três o manejo semi-intensivo. A população estudada é composta, por animais puros de raças exóticas como a Saanen, Parda Alpina, Anglonubiana e Toggenburg, por animais Meio Sangue e alguns sem raça definida (SRD. Foi realizado exame clinico e coleta de amostra de soro em 248 caprinos, bem como a aplicação de questinonário epidemiológico. A análise dos dados revelou uma soroprevalência de 40,73% (101/248. As amostras soropositivas foram todas provenientes das propriedades com manejo intensivo (5/8. A distribuição da soroprevalência em cada um destes criatórios foi 61% (54/89, 74,28% (26/35, 61,11% (11/18, 11,36% (5/44 e 75% (6/8. Diferença significativa (P0,05 quanto aos falares idade e sexo dos animais estudados.A serologic survey was performed using a agar gel immunodiffusion test (AGID with the Maedi/Visna virus antigen (p28 to estimate the seroprevalence of the caprine arthritisencephalitis virus infection (CAEV in a dairy goat population in the region of "Grande Fortaleza", in the state of Ceará, Brazil. In this study a total of eight flocks were examined, five included intensive and three semi-intensive managements. The population studied consisted of three groups: pure-bred animais of exotic races such as Saanen, Alpine Parda, Anglonubian and Toggenburg: crossbreeds and animais of undefined breed. Serum samples were colleted from 248 goats, clinicai analysis were performed, andan epidemiologic survey was applied. Analysis of the results showed a seroprevalence of 40.73% (101/248. All seropositive samples carne from the flocks with intensive management (5/8. The distribution of seroprevalence in each of these flocks was 61% (54/89. 74.28% (26/35, 61.11% (11/18, 11.36% (5/44 and 75% (6/8. A significam difference (P0.05 were observed related to age and sex of the studied animais.

Ana Célia Mendes Melo

1997-03-01

260

Soroprevalência da infecção pelo vírus da artrite-encefalite caprina (caev) no rebanho de caprinos leiteiros da região da Grande Fortaleza, Ceará, Brasil / Seroprevalence of the caprine arthritis-encephalitis vírus infection in dairy goats in the region of "Grande Fortaleza", Ceará, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foi realizada uma pesquisa sorológica, com base no teste de imunodifusão em ágar gel (AGID) com antígeno (p28) do vírus Maedi/Visna, para estimar a soroprevalência da infecção pelo vírus da Artrite-Encefalite Caprina (CAEV) na população de caprinos leiteiros da região da Grande Fortaleza, Ceará. O e [...] studo abrangeu um total de oito criatórios. dos quais cinco praticam o manejo intensivo e três o manejo semi-intensivo. A população estudada é composta, por animais puros de raças exóticas como a Saanen, Parda Alpina, Anglonubiana e Toggenburg, por animais Meio Sangue e alguns sem raça definida (SRD). Foi realizado exame clinico e coleta de amostra de soro em 248 caprinos, bem como a aplicação de questinonário epidemiológico. A análise dos dados revelou uma soroprevalência de 40,73% (101/248). As amostras soropositivas foram todas provenientes das propriedades com manejo intensivo (5/8). A distribuição da soroprevalência em cada um destes criatórios foi 61% (54/89), 74,28% (26/35), 61,11% (11/18), 11,36% (5/44) e 75% (6/8). Diferença significativa (P0,05) quanto aos falares idade e sexo dos animais estudados. Abstract in english A serologic survey was performed using a agar gel immunodiffusion test (AGID) with the Maedi/Visna virus antigen (p28) to estimate the seroprevalence of the caprine arthritisencephalitis virus infection (CAEV) in a dairy goat population in the region of "Grande Fortaleza", in the state of Ceará, Bra [...] zil. In this study a total of eight flocks were examined, five included intensive and three semi-intensive managements. The population studied consisted of three groups: pure-bred animais of exotic races such as Saanen, Alpine Parda, Anglonubian and Toggenburg: crossbreeds and animais of undefined breed. Serum samples were colleted from 248 goats, clinicai analysis were performed, andan epidemiologic survey was applied. Analysis of the results showed a seroprevalence of 40.73% (101/248). All seropositive samples carne from the flocks with intensive management (5/8). The distribution of seroprevalence in each of these flocks was 61% (54/89). 74.28% (26/35), 61.11% (11/18), 11.36% (5/44) and 75% (6/8). A significam difference (P0.05) were observed related to age and sex of the studied animais.

Ana Célia Mendes, Melo; Carlos Roberto, Franke.

 
 
 
 
261

Forma nervosa da artrite-encefalite caprina / Nervous form of caprine arthritis-encephalitis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese São descritos dois casos de caprinos, fêmeas, mestiços da raça Saanen de dois meses de idade com sinais clínicos de paresia de membros posteriores, incoordenação, dificuldade respiratória e caquexia, que foram submetidos à eutanásia, devido ao prognóstico desfavorável. Na necropsia, observou-se cong [...] estão do sistema nervoso central (SNC) e consolidação pulmonar nos dois caprinos. Microscopicamente, as alterações foram caracterizadas por leucoencefalomielite linfoplasmocítica multifocal, com vacuolização do neurópilo e esferoides axonais, leptomeningite, pneumonia intersticial não supurativa no caprino A e broncopneumonia bacteriana no caprino B. O exame de imuno-histoquímica (IHQ) foi positivo para o vírus da artrite-encefalite caprina em fragmento de tálamo. A prova de imunodifusão em gel de ágar (IDGA) foi realizada em vinte animais do rebanho de origem e dezesseis animais foram positivos. O diagnóstico da forma nervosa da infecção pelo vírus da artrite-encefalite caprina (CAEV) foi baseado no quadro clínico-patológico, IHQ e IDGA. Esta apresentação clínica da CAE pode ser pouco comum no Brasil, mas deve ser considerada em caso de doenças neurológicas em pequenos ruminantes. Abstract in english Two cases are described of female goats, Saanen crossbreds, two months old, with clinical signs of hind limb paresis, incoordination, difficulty breathing and cachexia, which were subjected to euthanasia due to unfavorable prognosis. At necropsy it was possible to observe that there was congestion o [...] f the central nervous system (CNS) and pulmonary consolidation in both goats. Microscopic changes were characterized by multifocal lymphoplasmacytic leucoencephalomielitis, with vacuolization of neuropile and axonal spheroids, leptomeningitis, interstitial nonsupurative pneumonia in goat A and bacterial bronchopneumonia in goat B. Immunohistochemistry (IHC) was positive for the caprine arthritis - encephalitis virus in thalamus fragments. The agar gel immunodiffusion (AGID) test was performed in sera sample of twenty animals and sixteen resulted positive. Diagnosis of the nervous form of caprine arthritis-encephalitis virus (CAEV) infection was based on clinical and pathological status, IHC and AGID. This clinical presentation of CAE could be uncommon in Brazil, but must be considered in case of neurologic diseases in small ruminants.

Karla Moraes Rocha, Guedes; Vanessa da Silva, Mustafa; Pedro Miguel Ocampos, Pedroso; David, Driemeier; Fábio Henrique Bezerra, Ximenes; Cristiano Barros de, Melo; José Renato Junqueira, Borges; Márcio Botelho de, Castro.

2191-21-01

262

Inquérito soroepidemiológico do lentivírus caprino e perfil das criações de caprinos na região do Baixo Médio São Francisco (BA) / Seroepidemiological survey of caprine arthritis encephalitis and profile of goat breeding systems in the region of Baixo Médio São Francisco (BA)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho teve como finalidade verificar a prevalência sorológica da lentivirose caprina (LVC) na microrregião de Juazeiro, na Bahia, por meio da técnica de imunodifusão em gel de agar (IDGA), bem como caracterizar os sistemas de criação da região. Para tal, foram avaliadas 693 amostras de soros [...] sanguíneos de caprinos de 46 propriedades rurais em diferentes localidades, pertencentes aos 8 municípios formadores da microrregião (Campo Alegre de Lourdes, Casa Nova, Curaçá, Juazeiro, Pilão Arcado, Remanso, Sento Sé e Sobradinho). Na realização das visitas, aplicou-se um questionário com ênfase nas informações referentes ao manejo sanitário. Das propriedades visitadas, todas apresentavam sistema de criação extensivo, com predomínio de animais sem raça definida, baixa produtividade e baixo índice de tecnificação, visando principalmente à obtenção de carne. As principais enfermidades relatadas foram linfadenite caseosa, diarreias, ectoparasitoses e ceratoconjuntivite. Quanto à soroprevalência, 0,29% (2/693) das amostras apresentaram sorologia positiva para a LVC. Os animais positivos pertenciam à mesma propriedade, no município de Curaçá, que apresentou 12,5% (1/8) de propriedades positivas, contrastando com 2,17% (1/46) de soroprevalência total dos rebanhos visitados. Estes resultados sugerem, portanto, a necessidade da efetivação de medidas preventivas na região, principalmente no momento em que se verifica a importação de animais para melhoramento genético. Abstract in english This work aimed to determine the serological prevalence of caprine artrithis encephalitis (CAE) in the microregion of Juazeiro, in the state of Bahia, using the technique of agar gel immunodiffusion (AGID) to characterize the farming systems of the region. We collected 693 blood serum samples of goa [...] ts from 46 farms in 8 different locations belonging to the municipalities forming the microregion (Campo Alegre de Lourdes, Casa Nova, Curaçá, Juazeiro, Pilão Arcado, Remanso, and Sobradinho). During the visits, a questionnaire was applied emphasizing information related to health management. All of the visited properties had extensive breeding systems, with predominance of mixed breed animals, low productivity and low technology rate, aiming mainly to use the meat. The main diseases reported were caseous lymphadenitis, diarrhea, ectoparasites and keratoconjunctivitis. Concerning seroprevalence, 0.29% (2/693) of samples tested positive for AGID. The positive animals belonged to the same property in the municipality of Curaçá, which showed 12.5% (1/8) of positive properties, in contrast to 2.17% (1/46) of total seroprevalence in the other visited properties. These results therefore suggest the need for new epidemiological surveys in the region, especially at a time when the importation of animals for genetic improvement is taking place.

Carla Caroline Valença de, Lima; Joselito Nunes, Costa; Thiago Sampaio de, Souza; Priscila, Martinez; Antônio Oliveira, Costa Neto; Antônio Vicente Magnavita, Anunciação; Maria das Graças Ávila Ribeiro, Almeida; Byanca Ribeiro, Araújo; Raymundo Rizaldo, Pinheiro.

2013-09-01

263

Wick materials by sol-gel processing  

International Nuclear Information System (INIS)

In capillary pumped loops (CPL) devices, the fine porous wick, located in the evaporator, provides the means for passively pumping the fluid through the system, using surface tension forces exerted onto a liquid in a small diameter pore at the liquid/vapor interface. The Naval Research Laboratory's Materials Science and technology Division and Naval Center for Space Technology have been investigating the use of sol-gel processing for development of organically modified ceramic wicks with micron or submicron pores, high porosity, low thermal conductivity and structural flexibility. Gels with average pore sizes as small as 0.5 ?m, 30-80% continuous porosity, some flexibility and thermal stability to at least 473K were successfully prepared. Microstructures of these hybrids were examined by scanning electron microscopy (SEM), and some conventional wick property testing were performed

264

Gel cast foam diesel particulate filters  

Energy Technology Data Exchange (ETDEWEB)

A new manufacturing route for foam ceramics based on gel casting has been developed and is being commercialised. Gel casting employs an organic monomer that is polymerised to cause the in-situ gelation of a foamed aqueous ceramic slurry. The primary advantage is the inherent flexibility of the process; the foams can be near net shape manufactured in a variety of shapes and sizes and after production are simply dried and fired. In addition, the porosity and pore size distribution can be varied to suit the application and a wide range of ceramics can be foamed with densities ranging from 5-40% of theoretical. Applications are diverse and include the potential to be used as diesel particulate filters (DPF). The present work examines this and concludes that filtration efficiencies of {>=}90% are achievable without generating a significant backpressure for the engine. (orig.)

Binner, J.G.P.; Hughes, S. [IPTME, Loughborough Univ., Loughborough (United Kingdom); Sambrook, R.M. [Dytech Corp. Ltd., Dronfield (United Kingdom)

2004-07-01

265

Ceramic sphere production by a gel casting  

International Nuclear Information System (INIS)

The technology of (Th,U)O2 microspheres production by gel casting and subsequente thermal treatment has been transferred from NUKEM CmbH 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?m) and the value of the specific surface (about 50 m2/g for calcined (Th,U)O2 and potentially higher than 200 m2/g for other ceramic materials). (Author)

266

Ceramica sphere production by a gel casting  

International Nuclear Information System (INIS)

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 ?mm) 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)

267

Similarity of wet granular packing to gels  

Science.gov (United States)

To date, there is still no general consensus on the fundamental principle that governs glass transition. Colloidal suspensions are ordinarily utilized as model systems to study the dynamical arrest mechanisms in glass or gels. Here, we tackle the problem using athermal granular particles. Slow dynamics and structural evolution of granular packing upon tapping are monitored by fast X-ray tomography. When the packing are wet and short-range attractive interactions exist, we find a large amount of locally favoured structures with fivefold symmetry, which bear great structural similarity to colloidal gels. In addition, these structures are almost absent in dry packing with similar packing fractions. The study leads strong support for the geometrical frustration mechanism for dynamic arrest in both thermal and athermal systems with attractive interactions. It also suggests nontrivial structural mechanism, if exists, for dynamic arrest in systems with purely repulsive interactions.

Li, Jindong; Cao, Yixin; Xia, Chengjie; Kou, Binquan; Xiao, Xianghui; Fezzaa, Kamel; Wang, Yujie

2014-09-01

268

Strip-Loaded Sol-Gel Waveguides  

Science.gov (United States)

Sol-gel is one of the most attractive techniques for production of silica-on-silicon integrated optical devices. In fact, it combines low cost with flexibility and ease of doping; thus, nonlinear and active compounds can be effectively included in the silica matrix. Here, the feasibility of applying the sol-gel technique to the realization of an erbium-doped optical amplifier is reported on, operating in the third telecommunication window. In particular, the development of an optimum strategy for the design and fabrication of a guiding structure in the strip-loaded configuration is described. Design optimization results, as well as fabrication results and measured characteristics, are described and discussed.

Forastiere, Michele A.; Pelli, Stefano; Righini, Giancarlo C.; Guglielmi, Massimo; Martucci, Alessandro; Ahmad, Munir M.; McCarthy, Orla; Yeatman, Eric; Vannucci, Antonello

269

Ordering phenomena in ABA triblock copolymer gels  

International Nuclear Information System (INIS)

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 latter is defined by the scattering density profile (polymer chain packing) at the domain boundary: a sharp boundary corresponds to less polydisperse domains and to increased order in the arrangement of the network nodes. The structure of the network can be described in terms of a highly distorted crystalline lattice with close-packed spheres or with cubic (presumably BCC) equilibrium morphology. The appearance of the latter is never detected in the gels with a stretched conformation of the midblock. (orig.)

270

Ordering phenomena in ABA triblock copolymer gels  

DEFF Research Database (Denmark)

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 latter is defined by the scattering density profile (polymer chain packing) at the domain boundary: a sharp boundary corresponds to less polydisperse domains and to increased order in the arrangement of the network nodes. The structure of the network can be described in terms of a highly distorted crystalline lattice with close-packed spheres or with cubic (presumably BCC) equilibrium morphology. The appearance of the latter is never detected in the gels with a stretched conformation of the midblock.

Mortensen, K.

1997-01-01

271

Local mobility and topology in gels  

International Nuclear Information System (INIS)

In the first section of this two part report entitled 'Separation of the motion around cross-link points from main chain motion in network samples' by Higgins, Ma and Hall, experimental evidence for topologically dependent diffusion in gels and rubbers is presented from high resolution neutron scattering experiments on deuterium labelled model trifunctional networks which show that the junction points move more slowly than the free chain centres by a factor of about two. In the second part by Warner entitled 'The dynamics of particular points on a polymer chain', the diffusional dynamics of particular points of a polymer chain is calculated in the Rouse approximation. The points considered correspond, in the case of incoherent neutron scattering, to the proton-labelled free ends of chains, crosslinks between chains in rubbers or gels, or the central monomers in branched or star polymers. Results derived are also relevant to NMR, ESR and computer simulation experiments. (U.K.)

272

Advanced ceramics by sol-gel processing  

International Nuclear Information System (INIS)

Sol-gel processing techniques have been used at Ansto to prepare a wide range of advanced ceramic materials, including Synroc, nanoceramics, electronic ceramics, bioceramics, thin films and membranes and multicomponent powders. The major current project involves the production of uniform, 30 to 50 microns spherical Synroc particles, with a high sorption capacity for nuclear waste. These particles are produced by spray-drying a concentrated titania/zirconia sol manufactured using proprietary techniques developed by the Advanced Materials Program at Ansto. A ceramic membrane filter is also being developed for the industrial processing of hot liquids. The filtration membrane is fabricated using sol-gel methods to produce a ceramic layer about 10 microns thick with closely controlled nano-sized pores. ills

273

Fundamentals of MRI measurements for gel dosimetry  

Energy Technology Data Exchange (ETDEWEB)

In radiotherapy gel dosimetry a humanoid phantom is irradiated according to the planned treatment of a patient. This results in a three-dimensional dose distribution. In order to read-out the gel dosimeter phantom, magnetic resonance imaging (MRI) is often used. Due to specific disturbances both the spatial and the dose reliability can be compromised. It is essential that the measurement sequence is optimized and that possible imaging artifacts are compensated in such a way that the proposed spatial and dose accuracy are met. In this review, several sources of disturbances are treated and compensation strategies are proposed. A code of good practice for the read-out technique is proposed. Finally, a tool for quality control of the imaging sequence is presented.

Deene, Y de [MR department (-1K12), Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium)

2004-01-01

274

Semiconductor Gel in Shark Sense Organs?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sharks can sense bioelectric fields of prey and other animals in seawater using an extraordinary system of sense organs (ampullae of Lorenzini) [9]. A recent study reported that these sense organs also enable sharks to locate prey-rich thermal fronts using a novel mode of temperature reception without ion channels. The study reported that gel extracted from the organs operates as a thermoelectric semiconductor, generating electricity when it is heated or cooled [2]. Here we report biophysical...

Fields, R. Douglas; Fields, Kyle D.; Fields, Melanie C.

2007-01-01

275

Ring-Resonator/Sol-Gel Interferometric Immunosensor  

Science.gov (United States)

A proposed biosensing system would be based on a combination of (1) a sensing volume containing antibodies immobilized in a sol-gel matrix and (2) an optical interferometer having a ring resonator configuration. The antibodies would be specific to an antigen species that one seeks to detect. In the ring resonator of the proposed system, light would make multiple passes through the sensing volume, affording greater interaction length and, hence, greater antibody- detection sensitivity.

Bearman, Gregory; Cohen, David

2007-01-01

276

Gel Evolution in Oil Based Drilling Fluids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Drilling fluids make up an essential part of the drilling operation. Successful drilling operations rely on adequate drilling fluid quality. With the development of new drilling techniques such as long deviated sections and drilling in ultra-deep waters, the standard of required performance of the drilling fluids continue to increase. Narrow pressure margins and low tolerance for barite sag requires accurate prediction of the gel evolution in drilling fluids. Increased knowledge of how dri...

Sandvold, Ida

2012-01-01

277

Ultrasensitive fluorescence detection of DNA sequencing gels  

Energy Technology Data Exchange (ETDEWEB)

During the three years of this grant we have: (1) Developed and applied a new theory for optimizing high-sensitivity fluorescence detection. (2) Developed and patented a new high-sensitivity confocal-fluorescence laser-excited gel-scanner. (3) Applied this scanner to the development of a new class of versatile and sensitive fluorescent dyes for DNA detection. (4) Developed methods for the detection of single fluorescent molecules by fluorescence burst detection. 11 refs., 10 figs.

Mathies, R.A.

1991-01-01

278

Sol-gel-derived lead titanate powders  

International Nuclear Information System (INIS)

A review of the literature will be presented detailing the complexation chemistry of lead-titanium sol-gel solutions. On the basis of this chemistry, the rationale will be described for the preparation of homogeneous, doped and undoped lead titanate powders. Powders prepared by Silicon Technologies Australia Limited (STA) using this complexation rationale will be described. Appropriate selection of hydrolysis conditions and reagents enabled production of powders of appropriate size and shape for piezoelectric applications

279

Sol-gel-derived lead titanate powders  

Energy Technology Data Exchange (ETDEWEB)

A review of the literature will be presented detailing the complexation chemistry of lead-titanium sol-gel solutions. On the basis of this chemistry, the rationale will be described for the preparation of homogeneous, doped and undoped lead titanate powders. Powders prepared by Silicon Technologies Australia Limited (STA) using this complexation rationale will be described. Appropriate selection of hydrolysis conditions and reagents enabled production of powders of appropriate size and shape for piezoelectric applications. 31 refs.

Watkins, I.D.; Tulloch, G.E.; Jenkins, S.M. [Silicon Technologies Australia Limited, NSW, (Australia)

1996-12-31

280

SANS study on pulley effect of slide-ring gel  

Science.gov (United States)

We have recently developed a novel kind of gel “slide-ring (SR) gel”, based on polyrotaxane consisting of thread-like molecules of poly(ethylene glycol) and rings of ?-cyclodextrin (CD) molecules. The SR gel has mobile cross-links. In order to improve the unique properties, i.e., “sliding motion” or “pulley effect” of the SR gels and to suppress the self-aggregation tendency of CD molecules, methylated polyrotaxane was synthesized by substituting hydroxyl group with methyl group on CD molecules. The structure of SR gel having methylated CD molecules was investigated by small angle neutron scattering.

Karino, Takeshi; Shibayama, Mitsuhiro; Okumura, Yasushi; Ito, Kohzo

2006-11-01

 
 
 
 
281

Structural evolution of phosphated alumina during sol-gel synthesis.  

Science.gov (United States)

Phosphated alumina gels were prepared by the sol-gel method. Gels were aged from 1 to 8 days in air. Gel structure evolution, as time went on, was followed by 27Al magic angle spinning nuclear magnetic resonance, X-ray diffraction, and small-angle X-ray scattering. It is concluded that the aging time is a crucial parameter in the formation of coordinately unsaturated sites of aluminum (AlIV and AlV). The gel network is shown to have a fractal structure. PMID:16853229

Lima, Enrique; Valente, Jaime; Bosch, Pedro; Lara, Victor

2005-09-22

282

SANS study on pulley effect of slide-ring gel  

International Nuclear Information System (INIS)

We have recently developed a novel kind of gel 'slide-ring (SR) gel', based on polyrotaxane consisting of thread-like molecules of poly(ethylene glycol) and rings of ?-cyclodextrin (CD) molecules. The SR gel has mobile cross-links. In order to improve the unique properties, i.e., 'sliding motion' or 'pulley effect' of the SR gels and to suppress the self-aggregation tendency of CD molecules, methylated polyrotaxane was synthesized by substituting hydroxyl group with methyl group on CD molecules. The structure of SR gel having methylated CD molecules was investigated by small angle neutron scattering

283

Comparative fluorescence two-dimensional gel electrophoresis using a gel strip sandwich assembly for the simultaneous on-gel generation of a reference protein spot grid.  

Science.gov (United States)

The comparison of proteins separated on 2DE is difficult due to gel-to-gel variability. Here, a method named comparative fluorescence gel electrophoresis (CoFGE) is presented, which allows the generation of an artificial protein grid in parallel to the separation of an analytical sample on the same gel. Different fluorescent stains are used to distinguish sample and marker on the gel. The technology combines elements of 1DE and 2DE. Special gel combs with V-shaped wells are placed in a stacking gel above the pI strip. Proteins separated on the pI strip are electrophoresed at the same time as marker proteins (commercially available purified protein of different molecular weight) placed in V-wells. In that way, grids providing approximately 100 nodes as landmarks for the determination of protein spot coordinates are generated. Data analysis is possible with commercial 2DE software capable of warping. The method improves comparability of 2DE protein gels, because they are generated in combination with regular in-gel anchor points formed by protein standards. This was shown here for two comparative experiments with three gels each using Escherichia coli lysate. For a set of 47 well-defined samples spots, the deviation of the coordinates was improved from 7% to less than 1% applying warping using the marker grid. Conclusively, as long as the same protein markers, the same size of pI-strips and the same technology are used, gel matching is reproducibly possible. This is an important advancement for projects involving comparison of 2DE-gels produced over several years and in different laboratories. PMID:22648808

Ackermann, Doreen; Wang, Weiqun; Streipert, Benjamin; Geib, Birgit; Grün, Lothar; König, Simone

2012-05-01

284

Gel Electrophoresis of Gold-DNA Nanoconjugates  

Directory of Open Access Journals (Sweden)

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.

W. J. Parak

2008-03-01

285

Decontamination using chemical gels, electrolytical swab, abrasives  

International Nuclear Information System (INIS)

Decontamination for decommissioning purposes differs from usual in-service decontamination procedures. The main factors which have to be considered in setting up decontamination procedures for nuclear installation decommissioning are: rapidity and ease of application, efficiency of decontamination, possibility of remote operation and small quantities of secondary generated wastes. The aim of this research work is to develop three decontamination methods which appear to be well adapted to dismantling. After laboratory tests where several procedures are compared, actual nuclear installation dismantling operations were performed. Among the decontamination procedures developed by CEA Cadarache, the following have been the subject of extensive studies: spraying of gels containing decontaminating agents, electropolishing with swab device and abrasive blasting. Examples of industrial applications of these three techniques which have been carried out are for these procedures: gels spraying performed on pieces coming from German BW Reactor ISAR, Brennilis Bitumization plant decontamination and dismantling, gels spraying decontamination performed on the cooling circuit of the graphite gas reactor G2 and a mechanical sodium cleaning method by abrasive blasting on SuperPhenix fuel storage drum intervessel. For each of these in-situ decontamination operations, a balance has to be made between the quantity of decontaminated metallic wastes and the amount of chemical reagent used as well as the quantity of secondary wastes generated. (author)

286

PRONIOSOMAL GEL OF FLURBIPROFEN: FORMULATION AND EVALUATION  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this research is to design proniosomal gel drug delivery system of flurbiprofen in a trial to overcome the adverse effects associated with oral administration of the drug. This can be overcome by the use of vesicular drug delivery system. Encapsulation of a drug in vesicular structure can be predicted to prolong the existence of the drug in the systemic circulation and thus enhance penetration into target tissue and reduce toxicity. Due to the limited solvent system present, the proniosomes formed were the mixture of many phases of liquid crystal, viz. lamellar, hexagonal and cubic phase liquid crystals. The potential of proniosomes as a transdermal drug delivery system of flurbiprofen was investigated by encapsulating the drug in various formulations of proniosomal gel composed of various ratios of sorbitan fatty acid esters, cholesterol, prepared by coacervation-phase separation method. The formulated systems were characterized in vitro for size, vesicle count, drug entrapment, drug release profiles and vesicular stability at different storage conditions. Stability studies for proniosomal gel were carried out for 4 weeks. The method of proniosome loading resulted in an encapsulation yield of 30.6 – 75.4%. Invitro studies showed prolonged release of entrapped flurbiprofen. At refrigerated conditions, higher drug retention was observed. It is evident from this study that proniosomes are a promising prolonged delivery system for flurbiprofen and have reasonably good stability characteristics.

Prajapati SK

2012-01-01

287

Bucky gel actuators optimization towards haptic applications  

Science.gov (United States)

An ideal plastic actuator for haptic applications should generate a relatively large displacement (minimum 0.2-0.6 mm, force (~50 mN/cm2) and a fast actuation response to the applied voltage. Although many different types of flexible, plastic actuators based on electroactive polymers (EAP) are currently under investigation, the ionic EAPs are the only ones that can be operated at low voltage. This property makes them suitable for applications that require inherently safe actuators. Among the ionic EAPs, bucky gel based actuators are very promising. Bucky gel is a physical gel made by grounding imidazolium ionic liquids with carbon nanotubes, which can then be incorporated in a polymeric composite matrix to prepare the active electrode layers of linear and bending actuators. Anyhow, many conflicting factors have to be balanced to obtain required performance. In order to produce high force a large stiffness is preferable but this limits the displacement. Moreover, the bigger the active electrode the larger the force. However the thicker an actuator is, the slower the charging process becomes (it is diffusion limited). In order to increase the charging speed a thin electrolyte would be desirable, but this increases the probability of pinholes and device failure. In this paper we will present how different approaches in electrolyte and electrode preparation influence actuator performance and properties taking particularly into account the device ionic conductivity (which influences the charging speed) and the electrode surface resistance (which influences both the recruitment of the whole actuator length and its speed).

Bubak, Grzegorz; Ansaldo, Alberto; Ceseracciu, Luca; Hata, Kenji; Ricci, Davide

2014-03-01

288

A reproducible, high throughput method for fabricating fibrin gels  

Directory of Open Access Journals (Sweden)

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.

Murphy Kaitlin C

2012-08-01

289

Scaling Behaviors and Mechanical Properties of Polymer Gels  

Science.gov (United States)

Polymer gels undergo a volume phase transition in solvent in response to an infinitesimal environmental change. This remarkable phenomenon has resulted in many potential applications of polymer gels. The understanding of its mechanical properties has both scientific and technological importance. For this purpose, we have developed a novel method for measuring Poisson's ratio, which is one of the most important parameters determining the mechanical property of gels. Using this method, Poisson's ratio in N-isopropyacryl -amide (NIPA) and polyacrylamide (PAAM) gels has been studied. We obtained that Poisson's ratio goes through a negative dip in both neutral and ionic NIPA gels, but positive in the PAAM gels. It was found that the scaling exponent delta depends on the details of chemical ingredients and polymerization process. In the salt solution, the delta depends on both the network ionization and the solvent salt concentration. The study of acoustic attenuation and velocity of NIPA gels reveals the dynamic scaling behavior of NIPA gels near the transition point. It has been found that there are four different pattern regions on the surface of constrained gel films depending on the temperature (or acetone concentration) and ionic strength of the sample, these patterns are associated with the mechanical instability of gel surface. The work presented in this dissertation will help ones both in the theoretical understanding and practical application of the gel system.

Li, Chunfang

290

Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth  

Science.gov (United States)

We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

Foster, Jonathan A.; Piepenbrock, Marc-Oliver M.; Lloyd, Gareth O.; Clarke, Nigel; Howard, Judith A. K.; Steed, Jonathan W.

2010-12-01

291

G-Quadruplex Guanosine Gels and Single Walled Carbon Nanotubes  

Directory of Open Access Journals (Sweden)

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.

Yuehua Yu

2013-12-01

292

Direct Force Measurements on Neurofilaments: Gel Expanded to Gel Condensed Transition  

Science.gov (United States)

Neurofilaments (NFs)--the major cytoskeletal constituent of axons in vertebrates, consist of three subunit proteins assembled to form filaments with protruding unstructured C-terminus sidearms. Liquid crystal gel networks of sidearm-mediated NF assemblies play a key role in the mechanical while disruptions of this network, due to over-accumulation or incorrect sidearm interactions, are a hallmark of motor neuron diseases. Using synchrotron SAXS [1,2] and microscopy techniques [1,3] we report a direct force measurement of reconstituted NF-gels under osmotic pressure (P), which revealed the role of subunit sidearms on structure and interaction of NFs. With increasing P, near physiological condition, the gels undergo an abrupt nonreversible gel expanded to gel condensed transition that indicates sidearm-mediated attractions between NFs. This attraction is consistent with an electrostatic model of interpenetrating chains.[4pt] [1] J.B. Jones, C.R. Safinya, Biophys. J. 95, 823 (2008);[0pt] [2] R. Beck et al., Nature Mat. (2009) in press;[0pt] [3] H. Hess et al. Langmuir 24, 8397 (2008)

Beck, R.; Deek, J.; Jones, J. B.; Safinya, C. R.

2010-03-01

293

Hydroxyapatite gels and nanocrystals prepared through a sol-gel process  

International Nuclear Information System (INIS)

We have investigated the effect of the Ca/P molar ratio on the structural and morphological properties of hydroxyapatite (HA) gels and nanocrystals. The sol-gel process was carried out in aqueous, and alternatively in alcoholic medium (50% water-50% ethanol), at 37 deg. C. Gel samples were obtained by drying the sols at 37 deg. C or at 80 deg. C, whereas powder samples were obtained by filtering the sols. Heat treatment at temperatures as low as 300 deg. C is enough to obtain pure HA from the gels with a Ca/P molar ratio of 1.00 and 1.67. At variance, heat treatment of the gels with a Ca/P of 2.55 always produces secondary phases. The degree of crystallinity of HA increases with the Ca/P molar ratio of the sols, and it is slightly affected by the presence of ethanol in the precipitation medium. Filtering of the sols provides powders constituted of nanocrystalline HA that exhibit degree of crystallinity, crystal morphology and thermal stability closely related to the sols composition

294

Ferramentas diagnósticas de Lentivirose de Pequenos Ruminantes: padronização da técnica de ELISA indireto / Diagnostic tools of small ruminant lentiviruses: standardization of indirect ELISA  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As Lentiviroses de Pequenos Ruminantes (LVPR) incluem a Maedi-Visna (MV) em ovinos e a Artrite Encefalite Caprina (CAE). Essas enfermidades estão difundidas no mundo e são responsáveis por grandes perdas na produtividade destes animais. Os LVPR são vírus RNA da subfamília Lentivirinae que causam uma [...] infecção persistente, sendo a detecção precoce uma das formas mais eficientes para limitar sua disseminação no rebanho. Visando contribuir com essas questões, este experimento foi realizado na Universidade Federal do Piauí (UFPI) em parceria com a Embrapa Caprinos e Ovinos, com o objetivo de padronizar a técnica de ensaio imunoenzimático indireto e compará-lo com a imunodifusão em gel de agarose no diagnóstico da CAE. Foram utilizadas 696 amostras de soros de caprinos machos e fêmeas oriundas do banco de soros da Unidade de Pesquisa de LVPR do Centro de Ciências Agrárias da UFPI. As amostras foram coletadas no período de janeiro de 2007 a março de 2010. Na padronização, verificou-se que 0,25 µg de proteína/poço, diluição de 1:200 do soro e concentração de 1:3.000 do conjugado anticorpo anti-IgG cabra apresentaram os melhores resultados. O ponto de corte obtido foi de 0,36. Na comparação, o Imunodifusão em Gel de Ágar (IDGA) detectou 128 (18,4%) amostras positivas, e o ELISA indireto (ELISA-i), 259 (37,2%). A sensibilidade e a especificidade do teste ELISA-i com relação ao IDGA foi de 94,5% e 75,7%, respectivamente. Verificou-se maior índice de positividade em caprinos acima de seis meses (p Abstract in english The Small Ruminant Lentiviruses (SRLVs) include Maedi-Visna (MV) of sheep and Caprine Arthritis-Encephalitis (CAE). These diseases are widespread and responsible for major production losses regarding sheep and goats. The SRLV is a RNA virus of the subfamily Lentivirus genus that causes persistent in [...] fections in goats. Early detection is one of the best ways to limit its spread in the herd. To contribute to these issues, this experiment was conducted at Universidade Federal do Piauí in partnership with Embrapa Goats and Sheep, with the objective of standardizing the technique of indirect ELISA (i-ELISA) and to compare it with Immunodiffusion in Agarose Gel to diagnose Caprine Lentiviruses (LC). Six hundred ninety six serum samples were used from the University Veterinary Hospital, Universidade Federal do Piauí, from January 2007 to March 2010. Standardization showed that 0.25 µg protein/well, a 1:200 dilution of the serum and concentration of 1:3,000 of the conjugated anti-goat IgG presented the best results. It was observed that the Agar Gel Immunodiffusion (AGID) detected 128 (18.4%) positive samples, and ELISA, 259 (37.2%). The sensitivity and specificity of i-ELISA regarding AGID were 94.5% and 75.7%, respectively. A higher prevalence was observed among animals older than six months (p

Caliandra Bona, Nascimento; Raymundo Rizaldo, Pinheiro; Francisco Selmo Fernandes, Alves; Roberta Lomonte Lemos de, Brito; Apoliana de Sousa, Rodrigues; Ricardo Abílio, Bezerra e Silva; Ney Rômulo de Oliveira, Paula; Maria do Carmo de Souza, Batista.

2014-03-01

295

Different Applications of Rheological Techniques in Studies of Physical Gels  

DEFF Research Database (Denmark)

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 associating protein filaments with the characteristic function of individual filaments. The proteins enable the cell to regulate the mechanical properties of the cell by sol-gel transition and a variety of crosslinking reactions. In the food industry texture of products are regulated by addition of gel-forming biopolymers. Physical gels are also used in the paint industry to minimize sedimentation. Delayed and controlled drug release is of importance in the pharmaceutical industry, and one way to obtain this control is to hide active components in physical gels. Two excellent reviews cover many aspects of biopolymer and physical gels [1,2]. The nature of physical gels has been debated for many years. In contrast to chemicallycrosslinked 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. Rheological techniques are used extensively in studies of physical gels and gelation. In the lecture some of the common techniques used in studies of gels will be addressed. Small amplitude oscillatory measurements are the most common type of measurement performed, and such measurements allow a determination of the elastic storage modulus, G’, and loss modulus, G”, as a function of e.g. frequency, temperature, or time. Two other techniques, which can be very useful for studies of gels, are creep and relaxation measurements. These techniques, which allow determinations of the compliance and the relaxation modulus, respectively, are particularly useful for investigating slow motions in gels and long-time properties. An example of how these different techniques have been used to investigate the rheological properties of sputum [4] will be discussed. The results demonstrate that sputum is a viscoelastic material and that both nucleic acids and actin filaments contribute to the viscoelastic properties of sputum from cystic fibrosis patients. Many simple methods have been developed over the years in industry to characterize products. The SAG test is widely used in the food industry to grade pectin samples and their ability to form gels. The test, which consists of a SAG measurement due to gravity of gels with a very precisely defined shape, is highly reproducible. However, it does not give any information about fundamental rheological properties of the pectin gels. Our attempt to understand more fundamental aspects of this test combined creep and oscillatory measurements together with finite element simulation. The results show [5] that pectin gels can be modeled as nearly ideal incompressible elastic materials, and equations connecting SAG number and the elastic storage modulus have been obtained. Solutions of tri-block copolymers of ethylene oxide and propylene oxide form micelles in water with increasing temperature due to the hydrophobic nature of poly(propylene oxide) at higher temperatures. At high concentration micelles pack in bcc structures and various other gel structures are also formed. The gel properties are dominated by repulsive interactions between micelles, and oscillatory measurements allow a determination of the repulsive potential between micelles. Oscillatory bulk modulus measurements have been used to determine the dynamics of unimer-micelle motions. The strain properties of physical gels are of major importance in many applications. When a gel is deformed with increasing strain or strain amplitudes most gels eventually

Hvidt, SØren

296

Dosimetry in HDR brachytherapy with Fricke-gel layers and Fricke-gel catheters  

Energy Technology Data Exchange (ETDEWEB)

Fricke-gel layer dosimeters (FGLD) and Fricke gel dosimetric catheters (FGDC) have been designed and tested with the aim of enquiring their suitability for HDR {sup 192}Ir brachytherapy source control and for in-vivo dose verification during treatment. Anisotropy function measurements have been carried out with FGLDs in which a thin plastic tube has been placed in for the {sup 192}Ir source insertion. FGDCs are constituted by plastic tubes (3 mm of external diameter and 13 cm of length) filled with the dosimeter-gel. Absorbed dose images and profiles were attained by means of optical analysis. Dedicated software has been developed both for achieving anisotropy function values and for obtaining reliable results in visible light absorbance measurements across the thin cylindrical dosimeters. Preparation and analysis procedures have been optimised. The results confirm that the proposed methods are very promising for HDR brachytherapy dosimetry.

Gambarini, G; Carrara, M; Negri, A; Invernizzi, M; Tenconi, C; Scotti, A; Pirola, L; Borroni, M; Tomatis, S; Fallai, C, E-mail: grazia.gambarini@mi.infn.i

2010-11-01

297

Sol-gel synthesis of hydroxyapatite; Sintese de hidroxiapatita via sol-gel  

Energy Technology Data Exchange (ETDEWEB)

Hydroxyapatite (HAp) has been established as the calcium phosphate based compound with most applications in the biological field. Among the numerous techniques for synthesis of HAp, the sol-gel processing route affords great control over purity and formed phases using low processing temperatures. In addition, the sol-gel approach offers an option for homogeneous HAp coating on metal substrates, as well as the ability to generate nanocrystalline powders. In this work, the sol-gel synthesis of HAp was investigated employing triethyl phosphate and calcium nitrate tetrahydrate as phosphorous and calcium precursors, respectively. The aging effect on phase composition and powder morphology of the final product was studied in terms of temperature and aging time. The powders were studied by using X-ray diffraction, Fourier transform infrared spectroscopy, particle size distribution by laser diffraction and scanning electron microscopy. (author)

Zupanski, M.D.; Lucena, M.P.P.; Bergmann, C.P., E-mail: michelledunin@yahoo.com.b [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)

2010-07-01

298

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

Energy Technology Data Exchange (ETDEWEB)

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.

Craig Joseph Fontenot

2001-12-31

299

Gniuždom?j? gelžbetonini? konstrukcij? stiprinimo gelžbetoniniais apvalkalais analiz?  

Directory of Open Access Journals (Sweden)

Full Text Available Šiame straipsnyje analizuojamos dvi pasirinktos gniuždom?j? gelžbetonini? element?, sustiprint? gelžbetoniniais apvalkalais, laikomosios galios skai?iavimo metodikos. Trumpai aprašomi laikomosios galios skai?iavimo metodik? algoritmai. Pateikiamos element? laikomosios galios pagrindin?s lygtys ir priklausomyb?s. Siekiant palyginti ir patikslinti laikomosios galios skai?iavimo metodikas, atlikti gniuždom?j? dispersiškai armuot? element?, sustiprint? gelžbetoniniais apvalkalais, laikomosios galios eksperimentiniai tyrimai. Atliktas teorini? skai?iavimo rezultat? palyginimas su eksperimentini? tyrim? rezultatais. Trumpai aprašomi analizuot? skai?iavimo metodik? bei eksperimentini? tyrim? privalumai ir tr?kumai. Remiantis gautomis skai?iavimo metodik? palyginimo ir eksperimentini? tyrim? išvadomis, pateikiama patobulinta laikomosios galios skai?iavimo metodika.Straipsnis lietuvi? kalba

Saulius Pilkavi?ius

2011-06-01

300

Continuous alumina gel fibers by sol-gel method using glycolic acid, aluminum nitrate and polyvinylpyrrolidone  

Directory of Open Access Journals (Sweden)

Full Text Available Continuous alumina fibers were prepared by sol-gel method. The spinning sol was obtained by mixing aluminum nitrate, glycolic acid and polyvinylpyrrolidone with a weight ratio of 10:3:1.5. 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 fibers. The fibers with a uniform diameter and smooth surface were obtained by sintering at 1473K, and its main phase was indentified as a-Al2O3.

Hongbin Tan

2011-09-01

 
 
 
 
301

Positron annihilation lifetime studies of sol-gel transition of carrageenan gels  

International Nuclear Information System (INIS)

Positron annihilation lifetime measurement was applied to study the sol-gel transition of anionic polysaccharide aqueous solutions in terms of free-volume parameters the size, intensity, and size distribution of free volumes of the gelation of K-form ?-carrageenan solutions as a function of temperature. Slight variations of free volume size and intensity against temperature were observed near 295 K. The correlation of free-volume data with other physical properties vibrational spectra (IR and Raman), conductivity, SAXS, elastic measurement, differential scanning calorimetry were investigated to understand the mechanism of sol-gel transition of carrageenan. (author)

302

Estudio serológico de fiebre aftosa y brucelosis en rebaños mixtos de camélidos y ovinos en la ecorregión de serranía en Apolobamba, La Paz - Bolivia / Foot and mouth disease and brucellosis serological survey in mixed herds of camelids and sheep in the highlands of Apolobamba eco-region, La Paz - Bolivia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish El objetivo del presente estudio fue determinar niveles serológicos de anticuerpos contra fiebre aftosa y brucelosis en rebaños mixtos de alpacas y ovejas en cuatro comunidades de la ecorregión serranía en el Área Natural de Manejo Integrado Nacional Apolobamba, La Paz - Bolivia, colindante con Perú [...] . Se colectaron 99 muestras de sangre de alpacas y 42 de ovinos de ambos sexos y edad diversa. Las muestras se procesaron mediante la prueba de inmunodifusión en gel agar para detectar anticuerpos VIA contra el virus de la fiebre aftosa y las pruebas de Aglutinación Rápida en Placa (prueba tamiz) y ELISA de competición (c-ELISA) (prueba confirmativa) para la detección de anticuerpos contra cepas lisas de Brucella sp. No se detectó anticuerpos contra fiebre aftosa o brucelosis. Abstract in english The objective of the present study was to determine serological levels of antibodies against foot and mouth disease (FMD) and brucellosis in mixed herds of alpacas and sheep in four communities of the highland ecorregion of the Apolobamba Protected Area (National Integrated Management Natural Area - [...] ANMIN), La Paz - Bolivia, bordering with Peru. Blood samples of 99 alpacas and 42 sheep of different sex and ages were collected. Plasma samples were tested for the detection of VIA antibodies against FMD virus using the agar gel immunodiffusion test (AGID-VIA) and for the detection of antibodies against smooth strains of Brucella spp. using a plate agglutination test as screening and a competitive ELISA (c-ELISA) as a confirmatory test. The results of the study showed no seropositive reactors for FMD or brucellosis.

L. Fabián, Beltrán-Saavedra S; Herminio, Ticona Ch; Rodolfo, Nallar G; José Luis, Gonzáles R.

303

Anticorpos anti Brucella abortus, anti Brucella canis e anti Leptospira spp. em raposas (Pseudalopex vetulus) do semiárido paraibano, Nordeste do Brasil / Detection of anti Brucella abortus, anti Brucella canis and anti Leptospira spp. Antibodies in hoary foxes (Pseudalopex vetulus) from semi-arid of Paraiba state, Northeastern region of Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo do presente trabalho foi determinar a ocorrência de anticorpos anti Brucella abortus, anti Brucella canis e anti Leptospira spp. em raposas (Pseudalopex vetulus). Para tanto, foram utilizadas 60 raposas atropeladas em rodovias no semiárido da Paraíba, Nordeste do Brasil. Para a detecção d [...] e anticorpos anti Brucella abortus, o teste do antígeno acidificado tamponado (AAT) foi empregado como teste de triagem, e a prova do 2-mercaptoetanol foi empregada como método confirmatório. Para o diagnóstico sorológico das infecções por Brucella canis e Leptospira spp., foram utilizados os testes de imunodifusão em gel de agar (IDGA) e soroaglutinação microscópica, respectivamente. Todas as amostras foram negativas na pesquisa de anticorpos anti Brucella canis e anti Leptospira spp. Das 60 raposas testadas, 16 (26,6%) foram positivas para anticorpos anti Brucella abortus no teste de AAT, e quatro (6,7%) amostras foram confirmadas no teste de 2-mercaptoetanol, sendo duas amostras com título 100 e duas com título 50. Abstract in english The aim of this research was to determine the occurrence of anti Brucella abortus, anti B. canis and anti Leptospira spp. antibodies in foxes (Pseudalopex vetulus). Sixty road-killed wild foxes from semi-arid of Paraiba state, Northeastern region of Brazil, were used. For the detection of anti B. ab [...] ortus antibodies, the buffered plate agglutination test (BPAT) was applied as a screening method and the 2-mercaptoethanol test as a confirmatory method. For serological diagnosis of infections by B. canis and Leptospira spp., the agar gel immunodiffusion test (AGID) and the microscopic agglutination test (MAT) were used, respectively. All samples were negative for anti B. canis and anti Leptospira spp. antibodies. Of the 60 foxes tested, 16 (26.6 %) were positive for anti B. abortus antibodies at BPAT, four (6.7%) samples were confirmed in the 2-mercaptoethanol test, and two samples presented titer 100 and two titer 50.

Sérgio Santos de, Azevedo; Maria Luana Cristiny Rodrigues, Silva; Carolina de Sousa Américo, Batista; Albério Antônio de Barros, Gomes; Sílvio Arruda, Vasconcellos; Clebert José, Alves.

304

Anticorpos anti Brucella abortus, anti Brucella canis e anti Leptospira spp. em raposas (Pseudalopex vetulus do semiárido paraibano, Nordeste do Brasil Detection of anti Brucella abortus, anti Brucella canis and anti Leptospira spp. Antibodies in hoary foxes (Pseudalopex vetulus from semi-arid of Paraiba state, Northeastern region of Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo do presente trabalho foi determinar a ocorrência de anticorpos anti Brucella abortus, anti Brucella canis e anti Leptospira spp. em raposas (Pseudalopex vetulus. Para tanto, foram utilizadas 60 raposas atropeladas em rodovias no semiárido da Paraíba, Nordeste do Brasil. Para a detecção de anticorpos anti Brucella abortus, o teste do antígeno acidificado tamponado (AAT foi empregado como teste de triagem, e a prova do 2-mercaptoetanol foi empregada como método confirmatório. Para o diagnóstico sorológico das infecções por Brucella canis e Leptospira spp., foram utilizados os testes de imunodifusão em gel de agar (IDGA e soroaglutinação microscópica, respectivamente. Todas as amostras foram negativas na pesquisa de anticorpos anti Brucella canis e anti Leptospira spp. Das 60 raposas testadas, 16 (26,6% foram positivas para anticorpos anti Brucella abortus no teste de AAT, e quatro (6,7% amostras foram confirmadas no teste de 2-mercaptoetanol, sendo duas amostras com título 100 e duas com título 50.The aim of this research was to determine the occurrence of anti Brucella abortus, anti B. canis and anti Leptospira spp. antibodies in foxes (Pseudalopex vetulus. Sixty road-killed wild foxes from semi-arid of Paraiba state, Northeastern region of Brazil, were used. For the detection of anti B. abortus antibodies, the buffered plate agglutination test (BPAT was applied as a screening method and the 2-mercaptoethanol test as a confirmatory method. For serological diagnosis of infections by B. canis and Leptospira spp., the agar gel immunodiffusion test (AGID and the microscopic agglutination test (MAT were used, respectively. All samples were negative for anti B. canis and anti Leptospira spp. antibodies. Of the 60 foxes tested, 16 (26.6 % were positive for anti B. abortus antibodies at BPAT, four (6.7% samples were confirmed in the 2-mercaptoethanol test, and two samples presented titer 100 and two titer 50.

Sérgio Santos de Azevedo

2010-02-01

305

Soroprevalence and risk factors associated to “Brucella canis” infection in dogs from Campina Grande, Paraíba Soroprevalência e fatores de risco associados à infecção por Brucella canis em cães da  

Directory of Open Access Journals (Sweden)

Full Text Available The prevalence of brucellosis due to Brucella canis was investigated in dogs from Campina Grande, Paraíba, Northern region of Brazil, and the risk factors for seropositivity were also analyzed. For this purposes, 170 dogs’ blood samples were collected during the rabies vaccination campaign, in September, 2003. The agar gel immunodiffusion test (AGID, by Brucella ovis lipopolysaccharides and proteins antigens, sample Reo 198, was used for serological diagnosis. The seroprevalence was 2.35% (95% CI = 0.64% - 5.91%. The epidemiological evidences showed that canine brucellosis due to Brucella canis in this area presented no association with the variables sex, age and management, however, there was statistic association between Brucella canis seropositivity and abortions occurrence.Foi investigada a soroprevalência de brucelose canina por Brucella canis em cães da cidade de Campina Grande, estado da Paraíba, Brasil, e realizado um estudo de possíveis fatores de riscos associados à soropositividade. Foram examinadas 170 amostras de soro sangüíneo de cães colhidas durante a campanha de vacinação anti-rábica animal, realizada em setembro de 2003. Para o diagnóstico sorológico da infecção por Brucella canis, foi empregada a prova de imunodifusão em gel de ágar (IDGA, utilizando antígeno de lipopolissacarídeos e proteínas de Brucella ovis, amostra Reo 198. A soroprevalência encontrada foi de 2,35% (IC 95% = 0,64% - 5,91%. O perfil epidemiológico da doença mostrou que o agente infecta em iguais condições os animais sem diferença de sexo, tipo de manejo e idade, havendo, contudo, associação estatística entre soropositividade para Brucella canis e ocorrência de abortamentos.

Robério Macedo de Oliveira

2008-09-01

306

Sol-gel processing to form doped sol-gel monoliths inside hollow core optical fiber and sol-gel core fiber devices made thereby  

Science.gov (United States)

A process of fabricating a fiber device includes providing a hollow core fiber, and forming a sol-gel material inside the hollow core fiber. The hollow core fiber is preferably an optical fiber, and the sol-gel material is doped with a dopant. Devices made in this manner includes a wide variety of sensors.

Shaw, Harry C. (Inventor); Ott, Melanie N. (Inventor); Manuel, Michele V. (Inventor)

2002-01-01

307

Connectivity in sol-gel silica glasses  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english In this work it is carried out a review on structural parameters related to the evaluation of pore connectivity of nanostructures. The work describes parameters and methods of evaluation of geometric parameters. The concepts of connectivity are applied to silica gels and glasses obtained from sol-ge [...] l process. The study of pores connectivity was carried out using a combination of geometric modeling and experimental evaluation of specific surface area and pore volume. The permeability of the pore structure is evaluated and a permeability geometric factor, Pg, is proposed.

Wander L., Vasconcelos.

1998-07-01

308

Biotechnology Laboratory: Gel Electrophoresis of Dyes  

Science.gov (United States)

A portion of the Partnership for Plant Genomics Education, hosted by the University of California-Davis, this PDF presents a student activity where students will use agarose gel electrophoresis to separate several different dyes. The lab is described as a âÂÂprecursor to DNA separationsâ and thus provides an important step in the subject matter. The lab provides for students: detailed instructions, background information, and a quiz and group questions. Answers to the questions, and also the general objective of the lab, are provided for the instructor. Overall, the lab is introductory in nature and perfect for any science classroom.

2008-12-05

309

Alignment and Nonlinear Elasticity in Biopolymer Gels  

CERN Document Server

We present a Landau type theory for the non-linear elasticity of biopolymer gels with a part of the order parameter describing induced nematic order. Our point of view is that all of the non-linear elastic behavior of these materials can be attributed to the onset of fiber alignment with induced 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 shear and extension, and also treat the case of a localized perturbation which is intended to be a simple model for a contacting cell in a medium.

Feng, Jingchen; Sander, Leonard M

2014-01-01

310

Sol-gel processing of ceramics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The sol-gel process can be considered as an interesting method for the synthesis of tailor-made ceramic raw materials. Two points of view are of special interest: powder synthesis and the processing of ultrafine raw materials. In the case of powder synthesis, high quality and multicomponent powders can be synthesized by control of surface chemistry and agglomerate-free subµm powder can be obtained. The preparation of tailor-made sols offers the possibility of powder-free processing of coatin...

Schmidt, Helmut K.

1991-01-01

311

Industrial applications of sol-gel technology  

International Nuclear Information System (INIS)

The purpose of this paper has been to provide a broad, rather than comprehensive view. We have presented a range of applications and only a selection of involved companies and researchers and have relied to a large extent on published information. Nevertheless, we are sure that our view of the importance of Sol-gel technology as an emerging technology, with enormous impact across a wide range of manufacturing, is demonstrated. Applications which are either in production or have been foreshadowed include four broad categories: coatings, fibres, powders and monoliths

312

Colloid-in-liquid crystal gels  

Science.gov (United States)

This presentation will describe investigations of the collective properties of colloidal particles that are dispersed in liquid crystalline solvents. A focus will be directed to recent observations of the gelation of particles dispersed in thermotropic liquid crystals. While a series of studies over the past decade have revealed two distinct mechanisms leading to gelation of particles in liquid crystalline solvents, our recent observations are inconsistent with both and hint at a third mechanism of gelation. These observations will be described along with examples of how the unique mechanical and optical properties of colloid-in-liquid crystal gels enable the design of biotic-abiotic interfaces.

Abbott, Nicholas

2013-03-01

313

Real Gel'fand-Mazur division algebras  

Directory of Open Access Journals (Sweden)

Full Text Available We show that the complexification (A˜,τ˜ of a real locally pseudoconvex (locally absorbingly pseudoconvex, locally multiplicatively pseudoconvex, and exponentially galbed algebra (A,τ is a complex locally pseudoconvex (resp., locally absorbingly pseudoconvex, locally multiplicatively pseudoconvex, and exponentially galbed algebra and all elements in the complexification (A˜,τ˜ of a commutative real exponentially galbed algebra (A,τ with bounded elements are bounded if the multiplication in (A,τ is jointly continuous. We give conditions for a commutative strictly real topological division algebra to be a commutative real Gel'fand-Mazur division algebra.

Olga Panova

2003-07-01

314

Comparative study of sol-gel-hydrothermal and sol-gel synthesis of titania-silica composite nanoparticles  

International Nuclear Information System (INIS)

Titania-silica composite nanoparticles were prepared by sol-gel-hydrothermal and sol-gel routes, respectively, and their physico-chemical and photocatalytic properties were compared. The results of XRD, TEM and BET surface areas showed that sol-gel-hydrothermal route led to anatase titania-silica composite nanoparticles with large specific surface area, but the sol-gel route tended to form mixture of anatase and rutile. The composite nanoparticles prepared by sol-gel-hydrothermal route had better thermal stability against phase transformation from anatase to rutile, agglomeration and particle growth than those prepared by sol-gel route. On the basis of XRD, FT-IR, XPS and 29Si MAS-NMR, a strong interaction was found between SiO2 and TiO2, and Ti-O-Si bonds formed during both the two routes. But more Ti-O-Si bonds formed in the composite nanoparticles prepared by sol-gel-hydrothermal route than those prepared by sol-gel route. As a result, the titania-silica composite nanoparticles prepared by sol-gel-hydrothermal route exhibited higher photocatalytic activity in decomposition of methylene blue than that prepared by sol-gel route, and it had excellent photocatalytic activity even after calcined at 1000 deg. C

315

FORMULATION AND EVALUATION OF POLYHERBAL GEL FOR ANTI - INFLAMMATORY ACTIVITY  

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Full Text Available ABSTRACT: In the present study, three medicinal plants Cynodon dactylon (L. Pers, Cassia tora Linn. and Cassia alata Linn having significant anti-inflammatory potential were selected to be formulated as polyherbal gels. The gels were prepared using the dried methanolic extract of Cassia tora Linn, Cassia alata Linn and Cynodon dactylon (L. Pers. Polyherbal gel formulations were evaluated for its pH, appearance and homogeneity, viscosity, spreadability and skin irritation studies. Assessment of Anti-inflammatory activity was done by carrageenan induced rat paw edema and formalin- induced rat paw edema. Individual and polyherbal gel of Cassia alata Linn,Cassia tora Linn. and Cynodon dactylon (L. Pers were found to possess anti-inflammatory effect in acute and chronic models. Polyherbal gel also showed synergistic effect as compared to individual gels which can be useful for the treatment of local inflammation.

Gouri Dixit*, Ganesh Misal, Vijay Gulkari and Kanchan Upadhye

2013-03-01

316

Structural colored gels for tunable soft photonic crystals.  

Science.gov (United States)

A periodically ordered interconnecting porous structure can be embodied in chemical gels by using closest-packed colloidal crystals as templates. The interconnecting porosity not only provides a quick response but also endows the porous gels with structural color arising from coherent Bragg optical diffraction. The structural colors revealed by porous gels can be regulated by several techniques, and thus, it is feasible to obtain desirable, smart, soft materials. A well-known thermosensitive monomer, N-isopropylacrylamide (NIPA), and other minor monomers were used to fabricate various structural colored gels. The selection of minor monomers depended on the targeted properties. This review focuses on the synthesis of templates, structural colored porous gels, and the applications of structural colored gel as smart soft materials for tunable photonic crystals. PMID:19306332

Harun-Ur-Rashid, Mohammad; Seki, Takahiro; Takeoka, Yukikazu

2009-01-01

317

A rapid, high resolution DNA sequencing gel system.  

Science.gov (United States)

We have developed a simple method which significantly increases the efficiency of manual DNA sequencing. This method increases both the ease of gel preparation and the quality of fragment resolution. Our system involves (i) casting of gels horizontally, without sealing around the plates; (ii) the use of a self-forming buffer gradient to stack bands in the lower part of the gel; (iii) separation of the samples on two 0.2-mm-thick acrylamide gels (4.5 and 4%) with overlapping readings; (iv) "nonsmiling" electrophoresis with very simple, self-made electrophoresis stands; and (v) prior to exposure in situ dry fixation of the gel matrix to the glass support without previous covalent binding of the gel. On average, we are able to read from nucleotide position 50 to position 600 without ambiguity. PMID:2221359

Lang, B F; Burger, G

1990-07-01

318

Further developments and applications of layer gel dosimetry  

Energy Technology Data Exchange (ETDEWEB)

The method used to perform dosimetry with Fricke-xylenol orange-infused gels in form of layers remains the most reliable method for in-phantom dose profiling and imaging in high fluxes of thermal and epithermal neutrons. Gel-dosimeters in form of layers really give the possibility not only of obtaining spatial dose distributions but also of achieving measurements of each dose contribution in neutron fields. These advantages arise from the layer-geometry thanks to which neutron transport is not sensibly altered, even if the elemental gel composition is changed adding particular isotopes (for example {sup 10}B), as necessary to perform the separation of dose contributions. The gel matrix composition and the experimental procedures, adopted for both dosimeter preparation and analysis, have been already described in previous works. In the present work, the improvements of the method employed for gel analysis, dose imaging and gel applications are illustrated.

Gambarini, G [Department of Physics of the University and INFN, Milan (Italy); Carrara, M [Department of Medical Physics, National Cancer Institute of Milan (Italy); Colli, V [Department of Physics of the University and INFN, Milan (Italy); Gay, S [Department of Physics of the University and INFN, Milan (Italy); Tomatis, S [Department of Medical Physics, National Cancer Institute of Milan (Italy)

2004-01-01

319

Surface sliding friction of negatively charged polyelectrolyte gels.  

Science.gov (United States)

The friction between two polyelectrolyte gels carrying the same or opposite sign of charges has been investigated using a rheometer. It is found that the friction was strongly dependent on the interfacial interaction between two gel surfaces. In the repulsive interaction case, especially, the friction was extremely low. The friction behavior is attempted to be described in terms of the hydrodynamic lubrication of the solvent layer between two like-charged gel surfaces, which is formed due to the electrostatic repulsion of the two gel surfaces. From the theoretical analysis (hydrodynamic mechanism), the friction behaviors were explained qualitatively, all of the experimental results, nevertheless, could not be understood well. The viscoelastic feature of the gel and the non-Newtonian behavior of water at the friction interface are considered to be important to elucidate the gel friction. PMID:17137762

Kagata, Go; Gong, Jian Ping

2007-04-15

320

Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel  

Directory of Open Access Journals (Sweden)

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 and development in in-vivo studies.Keywords: molecule mechanism, bacterial cells, S-T-Gel

Chen M

2011-11-01

 
 
 
 
321

Washing liquid effect on surimi gel rheological properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this research was to compare the rheological properties of the modori and su-wari gels, obtained from minced carp washed with water and electro-activated by water systems. The results of comparative analysis of rheological properties of suwari and modori gels from minced carp, washed with tap water, catholyte and anolyte are presented. Effective viscosity in all cases is reversibly reduced with increasing shear rate and is stabilized for all considered soft gel samples at strai...

Vinnov Alexey Sergeevich; Maevskaya Tatyana Nickolayevna; Dolganova Natalia Vadimovna

2013-01-01

322

Formation and characterization of sol-gel barium titanate  

International Nuclear Information System (INIS)

Sol-gel BaTiO3 has been obtained using a colloidal solution prepared by peptization of acetate derived gel with acetylacetone. IR spectroscopy studied the thermal destruction of organic components of the solution. Very thin films (thickness=44 nm) were deposited by using the dip-coating technique. The optical and dielectric properties of sol-gel BaTiO3 thin films were investigated in the visible spectral range

323

Availability of quercetin as functional ingredient in fish gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Quercetin, a natural antioxidant flavonol, was used as a functional ingredient in the preparation of surimi gels in order to study its antioxidant effects from technological and nutritional points of view. Gels were made from surimi containing either 0.105 % quercetin, fish oil (group ?3), or fish oil additionally supplemented with 0.105 % quercetin (group ?3-Q). Antioxidant capacity, measured by DPPH•, was reduced when quercetin was added to the surimi to made the gel, suggesting a modif...

Pe?rez Mateos, Miriam; Go?mez Guille?n, M. C.; Bravo, Laura; Goya, Luis; Solas, M. Teresa; Montero Garci?a, Pilar

2003-01-01

324

Pacman percolation: a model for enzyme gel degradation  

CERN Document Server

We study a model for the gel degradation by an enzyme, where the gel is schematized as a cubic lattice, and the enzyme as a random walker, that cuts the bonds over which it passes. The model undergoes a (reverse) percolation transition, which for low density of enzymes falls in a universality class different from random percolation. In particular we have measured a gel fraction critical exponent beta=1.0+-0.1, in excellent agreement with experiments made on the real system.

Abete, T; Lairez, D; Coniglio, A

2004-01-01

325

P159-T Computer Analysis of 2D Gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work identifies statistical algorithms which need to be included in analysis of 2D gels for accurate determination of differential spot intensity changes. Two-dimensional electrophoresis is a powerful tool for determining differential protein expression in complex mixtures, but 2D electrophoresis, to date, is not producing sufficiently reliable results due to the degree of gel variability generated by this methodology. The new DIGE procedure, comparing two samples in the same gel, does e...

Goldfarb, M. F.

2007-01-01

326

Volume Phase Transition of Polyelectrolyte Gels: Effects of Ionic Size  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-ioni...

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

2013-01-01

327

Accumulation of humic acid in DET/DGT gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 effects of humic and fulvic acids on the DGT detection of metal species have been observed, the gel permeation properties of the actual humic and fulvic acid compounds themselves have not been analyzed thus far. Here we show with DET (Diffusive Equili...

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

2010-01-01

328

UV photoannealing and RTP of thin sol-gel films  

International Nuclear Information System (INIS)

Various annealing methods for sol-gel films have been investigated. Thermal, photothermal, RTP and excimer laser annealing have been used to convert sol-gel precursor films into oxidic films. RTP annealing of sol-gel films yields better results than classical thermal annealing or excimer laser irradiation. Photochemical effects during RTP annealing contribute to obtain high-quality oxide films. The various annealing methods are illustrated by the annealing of alkoxide precursor films of tantalum, iron, nickel and yttrium

329

Semiconductor Gel in Shark Sense Organs?  

Science.gov (United States)

Sharks can sense bioelectric fields of prey and other animals in seawater using an extraordinary system of sense organs (ampullae of Lorenzini) [9]. A recent study reported that these sense organs also enable sharks to locate prey-rich thermal fronts using a novel mode of temperature reception without ion channels. The study reported that gel extracted from the organs operates as a thermoelectric semiconductor, generating electricity when it is heated or cooled [2]. Here we report biophysical studies that call into question this mechanism of sensory transduction. Our experiments indicate that the material exhibits no unusual thermoelectric or electromechanical properties, and that the thermoelectric response is an artifact caused by temperature effects on the measurement electrodes. No response is seen when non-metallic electrodes (carbon or salt bridges) are used, and ordinary seawater produces the same effect as shark organ gel when silver wire electrodes are used. These data are consistent with the voltages arising from electrochemical electrode potentials rather generated intrinsically within the sample. This new evidence, together with the anatomy of the organs and behavioral studies in the literature, best support the conclusion that the biological function of these sense organs is to detect electric fields. PMID:17904741

Fields, R. Douglas; Fields, Kyle D.; Fields, Melanie C.

2007-01-01

330

Il Gel Piastrinico in chirurgia orale  

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Full Text Available 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, preparato a partire da un prelievo contenuto di sangue venoso (30-60 ml, viene attivato mediante una miscela di calcio gluconato e batroxobina (un enzima similtrombinico. Nell’arco di 3-5 minuti si ottiene un bioprodotto pronto per rilasciare in situ, verosimilmente, quei GFs fondamentali per la guarigione e la rigenerazione dei tessuti circostanti.;Conclusioni: il gel piastrinico, una biotecnologia efficace, semplice e dai costi contenuti, offre ai clinici l’opportunità di poter disporre di uno strumento innovativo atto a ridurre i tempi di guarigione e le complicanze post-operative, migliorando notevolmente la qualità di vita dei pazienti;

Sacchi M.C.

2012-01-01

331

Thermoreversible Supramolecular Ion Gels via Hydrogen Bonding  

Science.gov (United States)

Ion gels are a novel class of functional materials of broad interest for advanced applications. We have developed a thermoreversible supramolecular ion gel system consisting of a poly(2-vinylpyridine-b-ethylene oxide-b-2-vinylpyridine) (P2VP-PEO-P2VP) triblock copolymer, a poly(4-vinylphenol) (PVPh) linear homopolymer, and an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMI][TFSA]), where a highly inter-connected transient polymer network is formed by hydrogen bonding between the P2VP endblocks and PVPh cross-linkers. This system exhibits novel physical properties, such as interesting dynamics and homopolymer clustering in the cross-links. The applicability of time-temperature superposition to this system is striking, resulting in a master curve that extends over 20 orders of magnitude in reduced frequency. The hydrogen-bonded phase can arrange into a hexagonally packed cylindrical morphology with long-range ordering, which reveals very slow kinetics and is thermodynamically stable only within a narrow temperature window. The highly tunable relaxation dynamics as well as shear modulus might enable materials design for specific applications.

Lei, Yu; Lodge, Timothy

2012-02-01

332

Catanionic gels based on cholic acid derivatives.  

Science.gov (United States)

In this paper, the preparation and characterization of an anionic and a cationic surfactant obtained by chemical modifications of a natural bile acid (cholic acid) are reported. The bile acid was modified by introducing a diamine or a dicarboxylic aromatic residue on the lateral chain. The pure cationic surfactant self-assembles in a network of fibers with a cross-section gyration radius of about 15.1 Å, providing hydrogels with a pH-dependent compactness. On the other hand, the anionic molecule gives rise to prolate ellipsoid micelles. Homogeneous catanionic mixtures have also been obtained, with molar fraction of each surfactant ranging from 0.125 to 0.875. At total surfactant concentration of 0.05% (w/v), the mixtures form gels of fibrils partially arranged in secondary twisted superstructures. Comparison of this concentration with the minimum gelation concentration of the pure cationic derivative (0.16% w/v) suggests that, in the mixtures, the presence of the electrostatic component in self-assembly of the molecules allows the formation of gels starting from more dilute samples. In view of these achievements, this work suggests that catanionic mixtures can be exploited to enhance the efficiency of gelators. PMID:24063307

di Gregorio, M Chiara; Pavel, N Viorel; Miragaya, Javier; Jover, Aida; Meijide, Francisco; Vázquez Tato, José; Tellini, Victor H Soto; Galantini, Luciano

2013-10-01

333

Adsorption of midmolecular peptides by fullerene modified silica gel  

Science.gov (United States)

The adsorption properties of raw and processed silica gels and of silica gels modified with fullerene (fullerene-silica gel nanosystems) toward serum midmolecular peptides of ischemic origin were examined. A high adsorption capacity of the nanosorbents was found. The influence of fullerenes on the condition of silica gel was studied by solid-state NMR, and an increase in the silanol fraction at the adsorbent surface was demonstrated. It was shown that presence of fullerene C60 in nanosorbents enables oxidation reaction of the adsorbed peptides, i.e., sorption of metabolites.

Melenevskaya, E. Yu.; Gribanov, A. V.; Podosenova, N. G.

2010-01-01

334

Application of CMPO containing gels to metal extraction  

International Nuclear Information System (INIS)

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

335

Polyacrylamide gels synthesized in the presence of surfactants  

Science.gov (United States)

The polymerization of acrylamide monomers in the presence of surfactant self-assemblies produces gels with variable pore architecture. Polyacrylamide gels were formed by polymerizing acrylamide plus a cross-linker in the presence of surfactants, which were then removed by soaking in distilled water. Gels formed in the presence of over 28% surfactant (by weight) formed clear, but became opaque upon removal of the surfactants. Other gels formed and remained clear. Several analytical techniques such as X-ray Scattering, Dynamic Rheology measurements, Optical Polarized Microscopy, and Atomic Force Microscopy (AFM) have been used to characterize the formation and the resulting gel structure. The surface morphology as imaged by AFM was studied by numerical scaling analysis. The surface morphology of the gels was studied by several one- and two-dimensional numerical scaling methods. The structure of the final gels were highly dependent on the amount of surfactant present during the formation of gels. At low surfactant concentrations (release systems for drug delivery, support matrices for bio-molecule separation. The process of gel formation in the presence of unreactive surfactants can also be extended to alter the structure of other polymer materials.

Chakrapani, Mukundan

336

Application of CMPO containing gels to metal extraction  

International Nuclear Information System (INIS)

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)

337

Silica scintillating materials prepared by sol-gel methods  

International Nuclear Information System (INIS)

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

338

Explorative data analysis of two-dimensional electrophoresis gels  

DEFF Research Database (Denmark)

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 spots on the gels for further investigation. The explorative approach in analysis of 2-D gels makes it possible, in a fastand convenient way, to screen many gels in order to determine the protein patterns that form clusters and could be selected for further examination.

Petersen, Marianne Kjerstine; Nesic, Ljiljana

2004-01-01

339

Synthesis of surface patterns on the gel surface  

Science.gov (United States)

The surface structures of hydrogels play important roles for many potential applications in physical, chemical and biomedical fields. Our idea is to precisely control the local properties of the one gel surface by incorporating different materials onto the given areas selected with a mask. We have successfully deposited NIPA polymer gel on the controlled area of the surface of an agarose gel. The pattern of the NIPA deposited area can be either visible or invisible by simply switching temperature above or below the low critical solution temperature (LCST) of the NIPA gel.

Zheng, Yindong; Wang, Changjie; Hu, Zhibing; Li, Yong

1997-10-01

340

Molecular Diffusion in Polysaccharide Gel Systems as Observed by NMR  

Science.gov (United States)

The diffusion coefficients D of dendrimers in agar gel and pullulan in gellan gel were determined by pulsed field gradient spin-echo (PFGSE) NMR measurements. The ratio of D to D 0 (diffusion coefficient in dilute solution) was used to estimate mesh size. The mesh size increased as the temperature fell below the gelling temperature, suggesting that the solute polysaccharides are involved in aggregation. Changes in mesh size explain the experimental results of water exudation from a stored agar gel under compression and the heat resistance of gellan gel in the presence of divalent cations.

Matsukawa, Shingo; Sagae, Daisuke; Mogi, Akiko

 
 
 
 
341

Production of silica gel from residual rice husk ash  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a study on the production of silica gel in hydrothermal process using residual rice husk ash. Measurements of the chemical composition, X-ray diffraction, infrared spectroscopy, particle size distribution, and pozzolanic activity were carried out in order to characterize the obtained material, and the optimal silica gel was selected for use as a mineral additive in cement pastes. The compressive strengths were determined for cement pastes containing silica gel (0.0, 2.5 or 5% by mass in different times. The results indicate that the mixtures containing silica gel showed improved mechanical behavior over all time periods evaluated.

Samantha Pinheiro Buás de Lima

2011-01-01

342

The magnesia-silica gel phase in slag cements: alkali (K, Cs) sorption potential of synthetic gels  

International Nuclear Information System (INIS)

Blends of Portland cement with blast furnace slag hydrate to yield two gel phases, one essentially a calcium silicate hydrate (C-S-H) composition, the other a magnesium silicate hydrate (M-S-H) composition: the two gel phases are essentially immiscible. Together, the gel phases comprise an important source of sorption potential for the alkalis present in ordinary cement and blending agents. M-S-H gels have been synthesised and their sorption potential measured for postassium (K) and cesium (Cs) at 25 deg. C by using fresh gels as well as gels previously aged at 85 deg. C for 6 months. The ability of slag-cement blends to lower pore fluid alkalinity generally, and in nuclear waste technology to incorporate Cs, is interpreted in terms of the sorption data

343

Fabrications and characterizations of dye-sensitized solar cells (DSSCs) with sol-gel derived gel electrolytes  

Science.gov (United States)

Dye Sensitized Solar Cells (DSSCs) have been fabricated by using sol-gel derived polymer gel electrolytes incorporating imidazolium ionic liquid. Two kinds of polymer gel electrolytes have been prepared. The first one is composed of siloxane polymer only, while the second one is composed of blend of siloxane and ethylene glycol polymers. The fabricated DSSC have the same structure configuration, namely ITO/Ti:ZnO/TiO2/Ru-dye/gelelectrolyte/Pt/ITO. DSSCs with the second type of gel electrolyte were found to exhibit much better photovoltaic performance in comparison to those with the first type of gel electrolyte. This fact is in agreement with the results from impedance spectroscopy measurements, which indicate more facile charge transfer process and much smaller ionic polarizations in the cell with the second type of gel electrolyte.

Sukmawati Arsyad, Wa Ode; Pujiarti, Herlin; Tola, Pardi Sampe; Herman, Hidayat, Rahmat

2013-09-01

344

A basic study of some normoxic polymer gel dosimeters  

International Nuclear Information System (INIS)

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 formulation than the MAGIC gel. (author)

345

Radiological properties of MAGIC normoxic polymer gel dosimetry  

International Nuclear Information System (INIS)

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 (?) 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 (?) 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 (?e) 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 densn, mass density, electron density and atomic number. The linear attenuation coefficient of unirradiated gel was very close to that of water. The ? 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.

346

Structural investigation of silica gel films by infrared spectroscopy  

Science.gov (United States)

Fourier transform infrared absorption spectroscopy has been utilized to characterize the structure of porous silica gel films, both deposited on c-Si substrates and free standing. The films were either dried at room temperature or subjected to partial densification at 400-450 °C. The spectra of the gel films are compared to those of thermal SiO2 grown on c-Si and to Kramers-Kronig analysis of the reflection spectra of bulk SiO2 gels and v-SiO2. The gel films show small frequency shifts compared to the latter spectra and they also exhibit new bands due to the presence of OH groups, although very little molecular water or residual organic species were found. The results are interpreted in terms of the gel structure. Compared to the thermal oxide, the sharp peak near 1070 cm-1 is narrower for the gels and the spread in intertetrahedral angles is estimated at 24° and 27° for room temperature dried and partially densified gels, respectively, compared to 33° for the thermal oxide. This is in agreement with a state of strain in the Si—O—Si bridges of the gels near the surface of the pores. The gel films have also a stronger shoulder near 1200 cm-1, whose intensity decreases with heat treatment of the gel. Its nature is related to the longitudinal optical (LO) component of the high-frequency vibration of SiO2 and it is suggested that the gel pores may account for the activation of the LO component.

Almeida, Rui M.; Pantano, Carlo G.

1990-10-01

347

Zirconyl-containing microspheric silica gel surfaces  

Science.gov (United States)

The adsorption properties of two samples of zirconyl-containing silica gels derived from zirconium oxychloride, polyetoxysiloxane oligomer 3% ZrOCl2/SiO2 (composite 1) and tetraetoxysilane 5% ZrOCl2/SiO2 (composite 2) were investigated by gas chromatography at low surface coverages. n-Alkanes and n-alkenes (C6-C8), C6H6 were used as test adsorbates, along with polar compounds whose molecules had different donor-acceptor interaction abilities. The dispersion and specific (electron-donor and electronacceptor) components of the energy of intermolecular interactions for the studied systems were determined from the experimental data on chromatographic retention. It was shown that composite 2 had a higher dispersion potential and higher surface energy characteristics of the surface's electron-donating and electronacceptor centers, as compared to composite 1.

Lanin, S. N.; Kabulov, B. D.; Vlasenko, E. V.; Kovaleva, N. V.; Lanina, K. S.; Strepetova, T. A.; Akhundzhanov, K. A.; Yunusov, F. U.

2011-01-01

348

Photoluminescence of sol-gel-prepared hafnia  

International Nuclear Information System (INIS)

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.

349

Indirect fluorometric detection in gel electrophysics  

Energy Technology Data Exchange (ETDEWEB)

Polyacrylamide gel electrophoresis separates biomolecules by virtueof their inherent charge or size, or a combination of the two. Thiswidely used bioanalytical technique has seen applications in areassuch as the separation of complex mixtures of proteins, gene sequenchingand mapping, and clinical diagnosis. The method displays unmatchedresolution of macromolecules, yet still utilizes detection methods which areslow and labor/minus/intensive. Commonly used methods such as Coomassie Blue andsilver staining can become complicated and may require twenty-four hoursto allow one to visualize the analyte. Autoradiography offers highsensitivity (10--100 pg)for the detection of radio-labelled analytes, butrequires exposure times of hours or days. A sensitive, yet rapid,quantitation method for electrophoresis would be quite useful. This paperdemonstrates the feasibility of employing indirect fluorometry as a rapidand potentially highly sensitive detection scheme for gelelectrophoresis. (AIP)

Hogan, B. L.; Yeung, E. S.

1989-02-01

350

Novel macroporous amphoteric gels: Preparation and characterization  

Directory of Open Access Journals (Sweden)

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 ?m. 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.

S. Kudaibergenov

2012-05-01

351

Colloidal Particles: Crystals, Glasses, and Gels  

Science.gov (United States)

Colloidal particles are microscopic solid particles suspended in a fluid. Colloids are small enough that thermal energy drives their dynamics and ensures equilibration with the suspending fluid; they are also large enough that their positions and motions can be measured precisely using optical methods, such as light scattering and laser-scanning confocal fluorescence microscopy. Colloidal suspensions are a powerful model system for the study of other phenomena in condensed matter physics, where the collective phase behavior of the solid particles mimics that of other condensed systems. We review three classes of interacting colloidal particles, crystals, glasses, and gels, each of which represents fascinating properties of colloidal particles as well as a model for more general types of materials and their behavior.

Lu, Peter J.; Weitz, David A.

2013-04-01

352

Clotrimazole nanoparticle gel for mucosal administration  

International Nuclear Information System (INIS)

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®. 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: ? Comparison between monoolein aqueous dispersion (MAD) and nanostructured lipid carrier (NLC). ? Clotrimazole (CLO) encapsulatNLC). ? Clotrimazole (CLO) encapsulated with high entrapment efficiency both in MAD and in NLC. ? The solid matrix of NLC controls CLO degradation better than MAD. ? CLO containing MAD and NLC exhibits a higher anticandidal activity than the free drug. ? Simple production of CLO-NLC based poloxamer gel, suitable for industry scaling up

353

Long-range forces extending from polymer-gel surfaces  

CERN Document Server

Aqueous suspensions of microspheres were infused around gels of varying composition. The solutes were excluded from zones on the order of 100 micrometers from the gel surface. We present evidence that this finding is not an artifact, and that solute-repulsion forces exist at distances far greater than conventional theory predicts. The observations imply that solutes may interact over an unexpectedly long range.

Zheng, J; Zheng, Jian-ming; Pollack, Gerald H.

2003-01-01

354

Biocatalysis with Sol-Gel Encapsulated Acid Phosphatase  

Science.gov (United States)

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…

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

2010-01-01

355

[The role of Dianatal Obstetric Gel in normal labor].  

Science.gov (United States)

In the following study we present Dianatal Obstetric Gel and its role in normal labor. We would like to determine the effect of the Obstetric gel on first and second stage of labor as well as prevention of perineal trauma. PMID:23234038

Mladenova, M; Dimitrakova, E; Amaliev, G; Pehlivanov, B

2012-01-01

356

Designing Reconfigurable Stimuli-Responsive Gel/Nanofibers Composites  

Science.gov (United States)

Using dissipative particle dynamics (DPD), we model the response of a composite gel, which encompasses active nanofibers, to external stimuli, such as light and temperature. The gel is constructed by crosslinking polymer chains in a coarse-grained manner. We probe the volume phase transition and swelling kinetics of the gels in explicit solvents. Our model is validated through qualitative comparisons with Flory-Huggins theory, and the effects of solvent quality, crosslink density and temperature are analyzed. By incorporating nanofibers into the gel matrix, we utilize different responses of the fibers and gel to variations in external stimuli. We focus on the fiber-gel and fiber-fiber interactions and establish routes for modeling composites with multiple types of fibers, which enable greater control of materials functionality. Utilizing the adaptability of gel/nanofiber composites, we design composites that can dynamically reconfigure shape via external stimuli to achieve actuation and locomotion. Our findings provide fundamental insights into the dynamics of gel-based composites, as well as guidelines for designing re-programmable multi-functional materials.

Yong, Xin; Kuksenok, Olga; Balazs, Anna

2013-03-01

357

Ion - exchange properties of tungstocerate (IV) gel matrices  

International Nuclear Information System (INIS)

Heteropolyacids and their salts have found a wide spread use in industry and nuclear applications. Some heteropolysolid matrices of Mo(VI) and W(VI) exhibit fairly good chemical stability towards high temperature and ionizing radiation as well as high selectivity to metal ions in mineral acid solutions. Tungstocerate(IV) gel matrices can be prepared in the form of granular particles suitable for packing into the form of chromatographic columns, which have found versatile applications in radiochemical separation, and concentration of radionuclides from aqueous solutions. The high mechanical stability of tungstocerate(IV) gel matrices is promising for use as the base matrix of chromatographic columns. The present study will include investigation of (ion exchange properties of tungstocerate(IV) gel matrices) as the following:1-Preparation of the tungstocerate(IV) gel matrices by mixing solutions of sodium tungstate with ammonium cerium sulfate.2-Characterization of the physical and chemical properties of the prepared gel matrix: stability in mineral acid solutions and their salts, density, crystallinity, infra-red spectra, thermal analysis, acidity, etc.3-Investigation of the selectivity patterns of the gel matrix for some radionuclides from aqueous solutions.4-Determination of the sorption capacity of the gel matrix for some metal cations from aqueous solutions.5-Applications of the gel matrix in radiochemical separation of mixture of radionuclides from each other, preparation of radioisotope generators and preconcentration of radionuclides from waste solutions

358

Spectroscopic studies of triethoxysilane sol-gel and coating process.  

Science.gov (United States)

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-H bending vibration has been found to be more sensitive to the skeletal structure than that of the Si-H stretching vibration. A higher temperature condition could favor the progression of hydrolysis and condensation. A temperature higher than 300 degrees 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. PMID:18060831

Li, Ying-Sing; Ba, Abdul

2008-10-01

359

Effects of Alcohols on Gelation Properties in Alumina Gel Casting  

Energy Technology Data Exchange (ETDEWEB)

The effects of Alcohols (1 {approx} 4 carbon of aliphatic chain) on the apparent gel induction time of alumina slurry, the drying rate of gel-structured body, and the mechanical property of gelcast bodies were investigated for the process control of alumina gelcasting. The results show that the apparent gel induction time of the alumina slurry and the drying rate of gel-structured bodies were increased with increasing an amount of alcohol. In the case of 20 wt% isopropyl alcohol added in alumina slurry, the apparent gel induction time was increased up to 120% and the drying rate was enhanced about 20% isopropyl alcohol added in alumina slurry, the apparent gel induction time was increased up to 120% and the drying rate was enhanced about 20%. Although the relative density and the strength of gelcasting bodies decreased roughly 4% and 30%, respectively, they were still machinable. In the case of adding 10 wt% of various alcohols in alumina slurry, the longer carbon-chain of the alcohol, the more effective it was on the apparent gel induction time, which increased 50 {approx} 90%. Furthermore, the drying rate of gel-structured bodies increased in the range of 20 {approx} 60%. The relative density and the tensile strength of gelcast bodies, with 10 wt% alcohols, decreased approximately 3 {approx} 5% and 20%, respectively, however, they were still machinable. 12 refs., 8 figs.

Ryu, Beyong Hwan; Lee, Jae Do [Advanced Material Division, Korea Research Institute of Chemical Technology, Taejon (Korea); Kim, Jin Woo; Kim, Do Jin [Department of Materials Science and Engineering, Chungnam National University, Taejon (Korea)

2001-05-01

360

Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials  

Science.gov (United States)

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…

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

2012-01-01

 
 
 
 
361

Automatic DNA sequencing for electrophoresis gels using image processing algorithms  

Directory of Open Access Journals (Sweden)

Full Text Available DNA electrophoresis gel is an important biologically experimental technique and DNA sequencing can be defined by it. Traditionally, it is time consuming for biologists to exam the gel images by their eyes and often has human errors during the process. Therefore, automatic analysis of the gel image could provide more information that is usually ignored by human expert. However, basic tasks such as the identification of lanes in a gel image, easily done by human experts, emerge as problems that may be difficult to be executed automatically. In this paper, we design an automatic procedure to analyze DNA gel images using various image processing algorithms. Firstly, we employ an enhanced fuzzy c-means algorithm to extract the useful information from DNA gel images and exclude the undesired background. Then, Gaussian function is utilized to estimate the location of each lane of A, T, C, and G on the gels images automatically. Finally, the location of each band on the gel image can be detected accurately by tracing lanes, renewing lost bands, and eliminating repetitive bands.

Jiann-Der Lee

2011-08-01

362

Gel Electrophoresis--The Easy Way for Students  

Science.gov (United States)

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…

VanRooy, Wilhelmina; Sultana, Khalida

2010-01-01

363

The Pozzolanic Activity of Calcined Clay – Silica Gel Composites  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of silica gel additive on pozzolanic activity of burned clays was investigated on this study. It was determined that calcined (600 ºC – 730 ºC clay of Saltiskiai quarry has very low pozzolanic activity (104 mg – 55 mg CaO/g. It was observed that during calcination process the fluorine ions from silica gel were not combined to another compounds but directly passed to atmosphere. Moreover, silica gel additive significantly increases the mentioned clay activity, which depends on the quantity of the used additive. It was determined that 10 % of silica gel additive increases the pozzolanic activity of composite with clay of Saltiskiai quarry up to 109 mg CaO/g, meanwhile the 80 % – unto 257 mg CaO/g. The same effect of silica gel additive was observed in the samples with Dukstyna quarry clay. It was found that the pozzolanic activity of Dukstyna clay-silica gel composite with 10 % of silica gel additive, burned at 600 ºC for 1h, was 7 % higher (168 mgCaO than the activity of the clay samples (157 mgCaO/g, whereas 229 mgCaO/g pozzolanic activity was reached than 80 % additive of silica gel was used. Despite this fact, the pozzolanic activity decreases when the calcination at 700 ºC – 860 ºC temperature was carried out. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2300

Raimonda KUBILI?T?

2013-12-01

364

A comparative study of new type polymer gel dosimeters  

International Nuclear Information System (INIS)

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)

365

The performance of gel technetium-99m generator  

International Nuclear Information System (INIS)

Technetium-99m, as one of the important radionuclides in nuclear medical science, has been widely used for diseases diagnosis in both developed and developing countries for many years. Technetium-99m can be obtained from both fission-type and gel-type Tc-99m generator. Fission-type generator was prepared by Molybdenum-99 separated from fission products of uranium-235 and gel-type was prepared by irradiating nature MoO3 in reactor, and a series of chemical and physical processes. This paper briefly describes the manufacturing technical process of gel-type Technetium-99 generator, including the preparation of target containing nature MoO3, the target irradiation in reactor, gel preparation, gel filtration and drying, dried gel cracking, generator loading and activity calibration of generator. The performances of gel-type Technetium-99m generator, such as elution efficiency, elution profile, the pH, Mo breakthrough, Zirconium content, radiochemical purity, radionuclidic purity, sterility and pyrogencity of eluate, are also expatiated in detail. Comparing with fission-type Technetium-99m generator, the defects of gel-type Technetium-99m generator are enumerated and their overcoming solutions are recommended in this paper. (author)

366

Modelling of erosion of bentonite gel by gel/sol flow  

International Nuclear Information System (INIS)

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 order of a metre per year the gel may penetrate several metres into the fracture when steady state is reached. The simulations were made with only sodium as counterion. Most simulations had sodium concentrations below the critical coagulation concentration, CCC. In the compacted bentonite at the fracture mouth it was 10 mM and 0.1 mM in the approaching water. At these concentrations the gel is expansive and can turn into a sol releasing colloidal particles. The low ion concentration has a strong impact on the fluid viscosity, which increases with decreasing ionic strength. At the same time, however the repulsion forces between the smectite particles increase causing a quicker expansion. Simulations with higher sodium concentrations had a marginal influence on the erosion rate. For the highest water flow rates the smectite loss could be up to 0.3 kg per year for one canister. This is more than one order of magnitude larger than what could be reached by smectite particle diffusion alone if fluid flow was neglected. In experiments in downward facing slits (fractures) it has been found that bentonite releases gel agglomerates much faster than expected. These are released and sediment also under conditions where it is expected that the smectite particles should have separated into individual smectite sheets, which would not noticeably be influenced by gravity. The reasons for this behaviour are not understood. In the modelling it is assumed that there are no other larger non-smectite particles that would be left behind to gradually build up a bed of particles that could act as filter, slowing down or even straining further smectite penetration into the fracture. The modelling results could therefore be highly pessimistic because bentonites contain tens of percent of accessory minerals that do not form colloids and the presence of which may cause the expansion to be slowed down by friction against the fracture walls

367

Modelling of erosion of bentonite gel by gel/sol flow  

Energy Technology Data Exchange (ETDEWEB)

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 order of a metre per year the gel may penetrate several metres into the fracture when steady state is reached. The simulations were made with only sodium as counterion. Most simulations had sodium concentrations below the critical coagulation concentration, CCC. In the compacted bentonite at the fracture mouth it was 10 mM and 0.1 mM in the approaching water. At these concentrations the gel is expansive and can turn into a sol releasing colloidal particles. The low ion concentration has a strong impact on the fluid viscosity, which increases with decreasing ionic strength. At the same time, however the repulsion forces between the smectite particles increase causing a quicker expansion. Simulations with higher sodium concentrations had a marginal influence on the erosion rate. For the highest water flow rates the smectite loss could be up to 0.3 kg per year for one canister. This is more than one order of magnitude larger than what could be reached by smectite particle diffusion alone if fluid flow was neglected. In experiments in downward facing slits (fractures) it has been found that bentonite releases gel agglomerates much faster than expected. These are released and sediment also under conditions where it is expected that the smectite particles should have separated into individual smectite sheets, which would not noticeably be influenced by gravity. The reasons for this behaviour are not understood. In the modelling it is assumed that there are no other larger non-smectite particles that would be left behind to gradually build up a bed of particles that could act as filter, slowing down or even straining further smectite penetration into the fracture. The modelling results could therefore be highly pessimistic because bentonites contain tens of percent of accessory minerals that do not form colloids and the presence of which may cause the expansion to be slowed down by friction against the fracture walls

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

368

Adsorption Characteristics of Silica Gels Treated with Fluorinated Silylation Agents  

Science.gov (United States)

Branched-chain polyfluorosilane (monochlorodimethyl[4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoroheptyl)-bonded silica gels were prepared. The surface properties of the silica gels modified with various organic silanes were evaluated by the adsorption density of polar and nonpolar gases calculated from adsorption isotherms of nitrogen, carbon dioxide, and normal butane gases. The polyfluorocarbon-bonded silica gel surface was found to be both hydrophobic and oleophobic in nature, whereas the hydrocarbon-bonded silica gel surface was characterized only as hydrophobic. The trifunctional fluorinated silane provides the silica gel surface with a more hydrophilic nature than the monofunctional silane because of the formation of a denser polymeric coating layer with a larger number of silanols. PMID:9056313

Monde; Nakayama; Yano; Yoko; Konakahara

1997-01-01

369

Laser CT evaluation on normoxic PAGAT gel dosimeter  

International Nuclear Information System (INIS)

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.

370

Laser CT evaluation on normoxic PAGAT gel dosimeter  

Science.gov (United States)

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.

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

2013-06-01

371

Tetracaine gel vs EMLA cream for percutaneous anaesthesia in children  

DEFF Research Database (Denmark)

We have evaluated the anaesthetic effect of tetracaine gel 1 g, applied for 45 min, compared with EMLA cream 2 g, applied for 60 min, in a randomized, double-blind study in 60 children aged 3-15 yr. Venous cannulation was performed 15 min after removal of the EMLA cream (n = 20) and tetracaine gel (n = 20). Cannulation was performed up to 215 min after removal of the tetracaine gel in another 20 patients. Significantly lower pain scores were recorded by the children treated with tetracaine gel compared with EMLA cream (P <0.02). Forty to 45% of children in the tetracaine groups reported no pain compared with only 10% in the EMLA group. Only minor adverse effects were observed. We conclude that tetracaine gel provided effective, rapid, long-lasting and safe local anaesthesia, and was significantly better than EMLA cream in reducing pain during venous cannulation in children using the recommended application periods for both formulations.

RØmsing, Janne; Henneberg, S W

1999-01-01

372

Spectroscopic study of sulforhodamine 640-doped sol-gel silica  

International Nuclear Information System (INIS)

The sol-gel process is a technique which provides a low-temperature route for the preparation of organic dye-doped porous silica glass. Extended UV transmission was observed for HCl-catalysed sol-gel silica. Properties of a solute may differ greatly between a free solution and that solution confined in pores of a sol-gel glass. Absorption and fluorescence properties of sulforhodamine 640-doped silica samples prepared by sol-gel process were investigated. In the TEOS-derived gel, the emission of the dye does not shift during aging but exhibits a large change during drying. The emission maximum of sulforhodamine 640 blue shifts was discussed as a function of increasing rigidity of the surrounding matrix

373

Surface coverage of polyaniline-coated silica gels  

International Nuclear Information System (INIS)

Silica gels of 15 ?m and 130 ?m mean sizes were covered by polyaniline hydrochloride nanofilms during polymerisation under different conditions. A surface coverage of the silica gel was determined from the C 1s or N 1s photoelectron spectra by two methods. The first one, the line shape analysis carried out by QUASES-Tougaard software, enables us to recognise also the surface morphology of the samples. The second method for the C 1s or N 1s peak area ratios originating from the polyaniline hydrochloride-coated silica gels an from the polyaniline hydrochloride standard. The results indicate that silica gel surfaces are not fully covered by the polyaniline hydrochloride film. The coverage values are consistent mutually, correlate well with polymerisation conditions and are in good agreement with a polyaniline hydrochloride content determined independently by burning the polyaniline hydrochloride-coated silica gel samples (Authors)

374

[Role of the i-gel in emergency airway management].  

Science.gov (United States)

The i-gel is a relatively new supraglottic airway, which has been shown to be useful during general anesthesia, and it may have a potential role during cardiopulmonary resuscitation. In a manikin study, we have found that, compared with laryngeal mask airways, the i-gel was significantly easier and faster to insert, due mainly to no-necessity of cuff inflation. One possible difficulty in using the i-gel during cardiopulmonary resuscitation is that the device cannot be fixed with the Thomas Tube Holder (Laerdal Medical Japan KK, Tokyo, Japan). A specially tailored device for cardiopulmonary resuscitation, recently has become available. The pack includes the i-gel O2 (which has a side port for oxygen delivery), a suction catheter, a sachet containing lubrication jelly, and a fixation strap. We describe the role of the i-gel during emergency airway management. PMID:24783621

Ueshima, Hironobu; Asai, Takashi

2014-04-01

375

Processing and characterization of Aloe vera gel for hydrogel preparation  

International Nuclear Information System (INIS)

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)

376

Investigation on Pmma-Based Gel Electrolyte for Electrochromic Devices  

Science.gov (United States)

Studies were carried out on gel electrolytes based on PMMA and non-aqueous solution of lithium salt, LiClO4 in the mixed solvent of propylene carbonate and ethylene carbonate (PC+EC). This paper reports the influences of polymer concentration and ratios of mixed solvent on the properties of gel electrolytes. The addition of polymer has increased the viscosity considerably without affecting the stable potential window, resulting in thermally stable gels. Result shows that addition of EC increases the conductivity by two order of magnitude as compared to that of PC alone. However conductivity decreases with addition of EC beyond 2:1 ratio of EC:PC. These gel electrolytes showed good room temperature conductivity in the order of 10-3 S/cm with high transmission in the visible region. This makes the gel a very promising electrolyte candidate for electrochromic device application.

Mohamad Mahbor, Kamisah

2002-12-01

377

Molecular Gels Materials with Self-Assembled Fibrillar Networks  

CERN Document Server

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...

Weiss, Richard G

2006-01-01

378

Fricke Gel Dosimeter Tissue-Equivalence a Monte Carlo Study  

Science.gov (United States)

Gel dosimetry has proved to be a valuable technique for absorbed dose distribution measurements in radiotherapy. FriXy-gel dosimeters consist of Fricke (ferrous sulphate) solution infused with xylenol orange. The solution is incorporated to a gel matrix in order to fix it to a solid structure allowing good spatial resolution and is imaged with a transportable optical system, measuring visible light transmittance before and after irradiation. This paper presents an evaluation of total photon mass attenuation coefficients at energies in the range of 50 keV-10MeV for the radiochromic FriXy gel dosimeter sensitive material. Mass attenuation coefficient estimations have been performed by means of Monte Carlo (PENELOPE) simulations. These calculations have been carried out for the FriXy gel sensitive material as well as for soft tissue (ICRU) and pure liquid water; a comparison of the obtained data shows good agreement between the different materials.

Valente, M.; Bartesaghi, G.; Gambarini, G.; Brusa, D.; Castellano, G.; Carrara, M.

2008-06-01

379

Verification of a non-diffusing gel dosimeter  

Science.gov (United States)

An evaluation of the diffusion coefficient of a genipin-gelatin gel dosimeter was carried out by fitting an inverse square root function to image profile data. A comparison was made with a Fricke-gelatin-xylenol orange (FGX) gel dosimeter, in which the ions are known to diffuse. The diffusion coefficient for this FGX gel, consisting of 0.5 mM ferrous ammonium sulphate, 50 mM sulphuric acid, 0.15 mM xylenol orange and 3 % by weight gelatin was 0.70 ± 0.05 mm2 h-1 at 5 Gy. The genipin-gelatin gel consisted of 50 ?M genipin, 4 % by weight gelatin and 100 mM sulphuric acid. The fitted parameter that is proportional to the diffusion coefficient did not significantly change over time, demonstrating that this genipin-gelatin gel is a non-diffusing dosimeter.

Davies, J. B.; Bosi, S. G.; Baldock, C.

2013-06-01

380

Formaldehyde increases MAGIC gel dosimeter melting point and sensitivity  

International Nuclear Information System (INIS)

Polymeric gel dosimeters are being used to verify three-dimensional (3D) dose distributions of different types of radiotherapy treatments, especially the most complexes ones. An important factor that can limit the wider use of this kind of dosimeter is temperature, as gel melting can destroy 3D information. This work shows that adding formaldehyde to the gel preparation increases the melting point, allowing its use in warmer environments, including up to body temperature. An addition of 3% in mass of the formaldehyde solution to a MAGIC type gel dosimeter increased its melting point from 25 to 69 deg. C. Also important were a 12.5% increase in gel sensitivity and an expressive decrease in relaxation rate R2 uncertainty. (note)

 
 
 
 
381

Formaldehyde increases MAGIC gel dosimeter melting point and sensitivity  

International Nuclear Information System (INIS)

Polymeric gel dosimeters are being used to verify three-dimensional (3D) dose distributions of different types of radiotherapy treatments, especially the most complexes ones. An important factor that can limit the wider use of this kind of dosimeter is temperature, as gel melting can destroy 3D information. This work shows that the addition of formaldehyde to the gel preparation increases the melting point, allowing its use in warmer environments, including up to body temperature. An addition of 3% in mass of the formaldehyde solution to a MAGIC type gel dosimeter increased its melting point from 25 to 69 deg. C. Also important were a 10.5% increase in gel sensitivity and an expressive decrease in relaxation rate R2 uncertainty that added to the agreement of the depth dose distribution measurement with the expected dosimetric data of the LINAC show the potential applicability of this new dosimeter for 3D dose verification.

382

Simulations of electrophoretic collisions of DNA knots with gel obstacles  

International Nuclear Information System (INIS)

Gel electrophoresis can be used to separate nicked circular DNA molecules of equal length but forming different knot types. At low electric fields, complex knots drift faster than simpler knots. However, at high electric field the opposite is the case and simpler knots migrate faster than more complex knots. Using Monte Carlo simulations we investigate the reasons of this reversal of relative order of electrophoretic mobility of DNA molecules forming different knot types. We observe that at high electric fields the simulated knotted molecules tend to hang over the gel fibres and require passing over a substantial energy barrier to slip over the impeding gel fibre. At low electric field the interactions of drifting molecules with the gel fibres are weak and there are no significant energy barriers that oppose the detachment of knotted molecules from transverse gel fibres

383

Detección de Mycobacterium avium subespecie paratuberculosis, por medio de PCR-anidada a partir de muestras de heces de ovinos / Detection of Mycobacterium avium subspecies paratuberculosis by nested-PCR of ovine fecal samples  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish La paratuberculosis es una enteritis granulomatosa de curso crónico ocasionada por Mycobacterium avium subespecie paratuberculosis (Map), afecta a rumiantes domésticos y silvestres. Map es excretada en las heces de animales que desarrollan la enfermedad, y la transmisión de la infección se da median [...] te la ingestión de alimentos y agua contaminados por heces de animales infectados. Con el objetivo de establecer el diagnóstico de paratuberculosis en ovinos por medio de la PCR-anidada a partir de muestras de heces, se trabajaron 204 muestras de heces y sueros de ovinos; las heces se evaluaron por PCR-anidada y cultivo bacteriológico, las muestras de sueros fueron analizadas por medio de inmunodifusión en agar gel (lDGA). Con la PCR-anidada se obtuvo un producto de amplificación 210 pb que corresponde a la IS900 de Map, en 61 de las 204 muestras. De éstas, 43 eran de animales positivos a IDGA y 18 negativos. Mediante cultivo bacteriológico se aislaron 17 cepas de Map; en este contexto, la IDGA detectó a 91 animales como positivos. La PCR-anidada permitió detectar en menor tiempo a mayor cantidad de animales que estaban eliminando al bacilo, aun cuando habían resultado negativos a la prueba serológica; este resultado se considera importante, ya que generalmente estos animales, al permanecer dentro de la granja, constituyen la principal fuente de infección para el rebaño. Se debe considerar a la PCR-anidada como alternativa, cuando se requiera el diagnóstico en breve tiempo, para conocer el estado sanitario del rebaño con respecto a paratuberculosis. Abstract in english Paratuberculosis is a chronic granulomatous enteritis caused by Mycobacterium avium subspecies paratuberculosis (Map), which affects wild and domestic ruminants. Map is shed in feces from infected animals. Transmission of the infection takes place by oral ingestion of the bacterium from contaminated [...] food and water with feces. With the objective to establish a paratuberculosis diagnosis in ovine by nested-PCR from fecal samples, 204 fecal and serum ovine samples were studied. Feces were evaluated by nested-PCR and bacterial culture, serum samples were analyzed by agar gel immunodiffusion (AGID). Nested-PCR yielded a 210 bp amplification product that corresponds to Map-IS900, in 61 out of 204 samples. From these, 43 were from AGID positive animals and 18 from negative animals. Seventeen Map strains were isolated by bacterial culture and AGID detected 91 positive animals. Nested-PCR allowed to detect, sooner, greater number of animals shedding bacillus, even when they had resulted negative to the serological test. This result is considered important because generally these animals, while remaining in the farm, constitute the main source of infection for the herd. Nested-PCR should be considered as an alternative, when a prompt result is required to know the health status of the herd with respect to paratuberculosis.

Norma G, Jaimes; Marco Antonio, Santillán Flores; Oscar A, Hernández Cruz; Dionisio, Córdova López; Claudia Celic, Guzmán Ruiz; Beatriz, Arellano Reynoso; Efrén, Díaz Aparicio; Víctor R, Tenorio Gutiérrez; Alfredo, Cuéllar Ordaz.

384

Detección de Mycobacterium avium subespecie paratuberculosis, por medio de PCR-anidada a partir de muestras de heces de ovinos / Detection of Mycobacterium avium subspecies paratuberculosis by nested-PCR of ovine fecal samples  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish La paratuberculosis es una enteritis granulomatosa de curso crónico ocasionada por Mycobacterium avium subespecie paratuberculosis (Map), afecta a rumiantes domésticos y silvestres. Map es excretada en las heces de animales que desarrollan la enfermedad, y la transmisión de la infección se da median [...] te la ingestión de alimentos y agua contaminados por heces de animales infectados. Con el objetivo de establecer el diagnóstico de paratuberculosis en ovinos por medio de la PCR-anidada a partir de muestras de heces, se trabajaron 204 muestras de heces y sueros de ovinos; las heces se evaluaron por PCR-anidada y cultivo bacteriológico, las muestras de sueros fueron analizadas por medio de inmunodifusión en agar gel (lDGA). Con la PCR-anidada se obtuvo un producto de amplificación 210 pb que corresponde a la IS900 de Map, en 61 de las 204 muestras. De éstas, 43 eran de animales positivos a IDGA y 18 negativos. Mediante cultivo bacteriológico se aislaron 17 cepas de Map; en este contexto, la IDGA detectó a 91 animales como positivos. La PCR-anidada permitió detectar en menor tiempo a mayor cantidad de animales que estaban eliminando al bacilo, aun cuando habían resultado negativos a la prueba serológica; este resultado se considera importante, ya que generalmente estos animales, al permanecer dentro de la granja, constituyen la principal fuente de infección para el rebaño. Se debe considerar a la PCR-anidada como alternativa, cuando se requiera el diagnóstico en breve tiempo, para conocer el estado sanitario del rebaño con respecto a paratuberculosis. Abstract in english Paratuberculosis is a chronic granulomatous enteritis caused by Mycobacterium avium subspecies paratuberculosis (Map), which affects wild and domestic ruminants. Map is shed in feces from infected animals. Transmission of the infection takes place by oral ingestion of the bacterium from contaminated [...] food and water with feces. With the objective to establish a paratuberculosis diagnosis in ovine by nested-PCR from fecal samples, 204 fecal and serum ovine samples were studied. Feces were evaluated by nested-PCR and bacterial culture, serum samples were analyzed by agar gel immunodiffusion (AGID). Nested-PCR yielded a 210 bp amplification product that corresponds to Map-IS900, in 61 out of 204 samples. From these, 43 were from AGID positive animals and 18 from negative animals. Seventeen Map strains were isolated by bacterial culture and AGID detected 91 positive animals. Nested-PCR allowed to detect, sooner, greater number of animals shedding bacillus, even when they had resulted negative to the serological test. This result is considered important because generally these animals, while remaining in the farm, constitute the main source of infection for the herd. Nested-PCR should be considered as an alternative, when a prompt result is required to know the health status of the herd with respect to paratuberculosis.

Norma G, Jaimes; Marco Antonio, Santillán Flores; Oscar A, Hernández Cruz; Dionisio, Córdova López; Claudia Celic, Guzmán Ruiz; Beatriz, Arellano Reynoso; Efrén, Díaz Aparicio; Víctor R, Tenorio Gutiérrez; Alfredo, Cuéllar Ordaz.

2008-12-01

385

21 CFR 878.3540 - Silicone gel-filled breast prosthesis.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Silicone gel-filled breast prosthesis. 878... Prosthetic Devices § 878.3540 Silicone gel-filled breast prosthesis. (a) Identification —(1) Single-lumen silicone gel-filled breast prosthesis....

2010-04-01

386

78 FR 19271 - Draft Guidance for Industry on Bioequivalence Recommendations for Metronidazole Vaginal Gel...  

Science.gov (United States)

...Recommendations for Metronidazole Vaginal Gel; Availability AGENCY: Food and Drug Administration...Recommendations for Metronidazole Vaginal Gel.'' The guidance provides specific recommendations...applications (ANDAs) for metronidazole vaginal gel. DATES: Although you can comment on...

2013-03-29

387

Don't Swallow Benadryl Itch Stopping Gel: Use on Skin  

Science.gov (United States)

... en Espanol Don't Swallow Benadryl Itch Stopping Gel—Use on Skin Search the Consumer Updates Section ... Benadryl Extra Strength Itch Stopping Gel Other Topical Gels Many pharmacies and grocery stores sell other diphenhydramine ...

388

40 CFR 721.9680 - Alkaline titania silica gel (generic name).  

Science.gov (United States)

...2010-07-01 2010-07-01 false Alkaline titania silica gel (generic name...Chemical Substances § 721.9680 Alkaline titania silica gel (generic name...substance identified generically as an alkaline titania silica gel (PMN...

2010-07-01

389

Physical properties of nanoparticle silica gel doped with CdS prepared by sol-gel technique  

Science.gov (United States)

CdS/silica xerogel glasses were prepared via silica gels containing mixture solution of 0.2 M (CdCl2 and thiourea) with molar ratio 1:1. Doping the gels with this mixture solution and its heat treatment gave transparent yellow silica-gel glasses doped with CdS crystals. X-ray diffraction and transmission electron microscope make it possible to evaluate the nanoparticle size of the prepared samples. The nanoparticle size was dependent on the concentration of the dopant materials and the heating temperature. In the optical transmission spectra, the absorption edge exhibited a blue shift compared to that of the bulk CdS, and its energy shift was reciprocally proportional to the square of the radius. Thus the quantum-size effect could be found for the silica gel containing CdS prepared by the sol-gel process. The energy band gap shifted to higher energy for smaller nanoparticle size.

Battisha, I. K.

390

Açúcar granulado ou em gel no tratamento de feridas em cães / Granulated sugar and sugar gel in treating canine wounds  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O açúcar é um dos produtos mais utilizados para tratamento de feridas em medicina veterinária. Sua principal vantagem é o efeito higroscópico nos tecidos e morte das bactérias por plasmólise, tornando-o um bactericida pelo efeito físico realizado, sem levar à resistência bacteriana. O objetivo deste [...] experimento foi comparar a evolução cicatricial de feridas cutâneas com o uso tópico de açúcar na forma granulada e na forma de gel. Foram tratadas 16 feridas de cães, das quais oito receberam tratamento com açúcar granulado (grupo A) e oito com gel de açúcar (grupo G). O tempo de tratamento, independente do grupo, levou, no mínimo, sete dias e, no máximo, 14. Quanto à aplicabilidade, o gel demonstrou melhor adesão nas feridas e preenchimento do produto no subcutâneo de forma mais efetiva que o açúcar granulado. Conclui-se que tanto o gel quanto o açúcar foram efetivos na cicatrização das feridas dos animais deste experimento, sendo que o gel demonstrou precocidade na retração cicatricial nos primeiros sete dias. Abstract in english Sugar is one of the most widely used products in the treatment of wounds in veterinary medicine. Its main advantage is the hygroscopic effect on tissues and the bacterial death by plasmolysis, making it a bactericidal agent due to the physical effect observed, without leading to bacterial resistance [...] . The aim of this experiment was to compare cicatricial evolution of cutaneous wounds with the topical use of sugar either granulated or as gel. Sixteen canine wounds were treated: eight with granulated sugar (group A) and eight with sugar gel (group G). Treatment time, independent of the group, took at least seven days and a maximum of 14. Concerning applicability, gel sugar showed better adhesion to wounds and subcutaneous filling more effectively that granulated sugar. It is concluded that both granulated and gel sugar were effective in healing skin wounds, the gel being precocious in cicatricial retraction within the first seven days of treatment.

Gabriele Maria Callegaro, Serafini; João Eduardo Wallau, Schossler; Anne Santos do, Amaral; Luciana Hermes, Dutra; Angela Piantá, Dibi; Priscila, Drogemoller; Cristiane de Lima, Athayde.

2213-22-01

391

Açúcar granulado ou em gel no tratamento de feridas em cães / Granulated sugar and sugar gel in treating canine wounds  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O açúcar é um dos produtos mais utilizados para tratamento de feridas em medicina veterinária. Sua principal vantagem é o efeito higroscópico nos tecidos e morte das bactérias por plasmólise, tornando-o um bactericida pelo efeito físico realizado, sem levar à resistência bacteriana. O objetivo deste [...] experimento foi comparar a evolução cicatricial de feridas cutâneas com o uso tópico de açúcar na forma granulada e na forma de gel. Foram tratadas 16 feridas de cães, das quais oito receberam tratamento com açúcar granulado (grupo A) e oito com gel de açúcar (grupo G). O tempo de tratamento, independente do grupo, levou, no mínimo, sete dias e, no máximo, 14. Quanto à aplicabilidade, o gel demonstrou melhor adesão nas feridas e preenchimento do produto no subcutâneo de forma mais efetiva que o açúcar granulado. Conclui-se que tanto o gel quanto o açúcar foram efetivos na cicatrização das feridas dos animais deste experimento, sendo que o gel demonstrou precocidade na retração cicatricial nos primeiros sete dias. Abstract in english Sugar is one of the most widely used products in the treatment of wounds in veterinary medicine. Its main advantage is the hygroscopic effect on tissues and the bacterial death by plasmolysis, making it a bactericidal agent due to the physical effect observed, without leading to bacterial resistance [...] . The aim of this experiment was to compare cicatricial evolution of cutaneous wounds with the topical use of sugar either granulated or as gel. Sixteen canine wounds were treated: eight with granulated sugar (group A) and eight with sugar gel (group G). Treatment time, independent of the group, took at least seven days and a maximum of 14. Concerning applicability, gel sugar showed better adhesion to wounds and subcutaneous filling more effectively that granulated sugar. It is concluded that both granulated and gel sugar were effective in healing skin wounds, the gel being precocious in cicatricial retraction within the first seven days of treatment.

Gabriele Maria Callegaro, Serafini; João Eduardo Wallau, Schossler; Anne Santos do, Amaral; Luciana Hermes, Dutra; Angela Piantá, Dibi; Priscila, Drogemoller; Cristiane de Lima, Athayde.

392

Topical permeation characteristics of diclofenac sodium from NaCMC gels in comparison with conventional gel formulations.  

Science.gov (United States)

Topical gel formulations of diclofenac sodium were prepared by using sodium carboxymethylcellulose (NaCMC), a low-toxicity cellulose polymer as a gel-forming material that is biocompatible and biodegradable. The influence of various formulation variables, such as initial drug concentrations and NaCMC concentration, and certain skin permeation enhancers on release characteristics of the diclofenac sodium from the prepared gels through a standard cellophane membrane was studied in comparison with four commercially available gel formulations of diclofenac sodium,. The cumulative amounts released and the apparent release rates were higher for the prepared gels in comparison with the commercial formulations. Skin permeation studies using abdominal rat skin revealed good improvement of skin permeation characteristics of diclofenac sodium using NaCMC gels as compared to the commercial gels. The cumulative amount permeated at 6 h (microg/cm2), steady-state flux Jss (microg/cm2 h), lag time tL (h), permeability coefficient kp (cm/s), partition coefficient k, and diffusion coefficient D (cm2/s) were determined for the prepared gels in comparison with the commercial gels. Skin permeation enhancers such as isopropyl alcohol (IPA), Tween 80, and alpha-tocopherol polyethylene glycol succinate (TPGS) exhibited little or no effect on the permeation characteristics of diclofenac sodium. Infrared (IR) spectrum and differential scanning calorimetry (DSC) studies on the pure diclofenac sodium, NaCMC, and their physical mixture at a 1:1 ratio revealed that there was no positive evidence for the interactions between the drug and NaCMC, indicating the compat