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Sample records for agar streak dilution

  1. Screening fungicides for use in fish culture: Evaluation of the agar plug transfer, cellophane transfer, and agar dilution methods

    USGS Publications Warehouse

    Bailey, Tom A.

    1983-01-01

    The reliability, reproducibility, and usefulness of three screening methods -- the cellophane transfer, the agar plug transfer, and the agar dilution -- to screen aquatic fungicides were evaluated. Achlya flagellata and Saprolegnia hypogyna were exposed to 1, 10, and 100 mg/L of malachite green to test each method. The cellophane transfer and agar plug transfer techniques had similar reliability and reproducibility in rating fungicidal activity, and were both superior to the agar dilution technique. The agar plug transfer and agar dilution techniques adequately projected in vivo activity of malachite green, but the cellophane transfer technique overestimated its activity. Overall, the agar plug transfer technique most accurately rated the activity of malachite green and was the easiest test to perform. It therefore appears to be the method of choice for testing aquatic fungicides.

  2. Assessment of Etest as an alternative to agar dilution for antimicrobial susceptibility testing of Neisseria gonorrhoeae.

    PubMed

    Liu, Hsi; Taylor, Thomas H; Pettus, Kevin; Trees, David

    2014-05-01

    We studied whether the Etest can be used as an alternative to agar dilution to determine antimicrobial susceptibilities of ceftriaxone, cefixime, and cefpodoxime in Neisseria gonorrhoeae surveillance. One hundred fifteen clinical and laboratory isolates of N. gonorrhoeae were tested following the Clinical Laboratory Improvement Amendments (CLIA)-approved CLSI standard agar dilution method and, separately, by the Etest according to the manufacturer's recommendations. The MICs were determined and compared. Ten laboratory-generated mutants were used to simulate substantially nonsusceptible specimens. The Etest and agar dilution methods were well correlated. Statistical tests produced regression R2 values of 88%, 82%, and 85% and Pearson correlation coefficients of 92%, 91%, and 92% for ceftriaxone, cefixime, and cefpodoxime, respectively. When paired comparisons were made, the two tests were 88.7%, 80%, and 87% within 1 log2 dilution from each other for ceftriaxone, cefixime, and cefpodoxime, respectively. The within-2-log2 agreements were 99.1%, 98.3%, and 94.8% for ceftriaxone, cefixime, and cefpodoxime, respectively. Notwithstanding the good correlations and the within-2-log2 general agreement, the Etest results produced slightly lower MICs than the agar dilution results. In conclusion, we found that the Etest can be effectively used as an alternative to agar dilution testing to determine the susceptibility of N. gonorrhoeae to ceftriaxone, cefixime, and cefpodoxime, although we recommend further research into extremely resistant isolates. For isolates within the typical range of clinical MICs, reexamination of the Etest interpretation of susceptible and nonsusceptible categories would likely allow for successful transition from agar dilution to the Etest. PMID:24554750

  3. Assessment of Etest as an Alternative to Agar Dilution for Antimicrobial Susceptibility Testing of Neisseria gonorrhoeae

    PubMed Central

    Taylor, Thomas H.; Pettus, Kevin; Trees, David

    2014-01-01

    We studied whether the Etest can be used as an alternative to agar dilution to determine antimicrobial susceptibilities of ceftriaxone, cefixime, and cefpodoxime in Neisseria gonorrhoeae surveillance. One hundred fifteen clinical and laboratory isolates of N. gonorrhoeae were tested following the Clinical Laboratory Improvement Amendments (CLIA)-approved CLSI standard agar dilution method and, separately, by the Etest according to the manufacturer's recommendations. The MICs were determined and compared. Ten laboratory-generated mutants were used to simulate substantially nonsusceptible specimens. The Etest and agar dilution methods were well correlated. Statistical tests produced regression R2 values of 88%, 82%, and 85% and Pearson correlation coefficients of 92%, 91%, and 92% for ceftriaxone, cefixime, and cefpodoxime, respectively. When paired comparisons were made, the two tests were 88.7%, 80%, and 87% within 1 log2 dilution from each other for ceftriaxone, cefixime, and cefpodoxime, respectively. The within-2-log2 agreements were 99.1%, 98.3%, and 94.8% for ceftriaxone, cefixime, and cefpodoxime, respectively. Notwithstanding the good correlations and the within-2-log2 general agreement, the Etest results produced slightly lower MICs than the agar dilution results. In conclusion, we found that the Etest can be effectively used as an alternative to agar dilution testing to determine the susceptibility of N. gonorrhoeae to ceftriaxone, cefixime, and cefpodoxime, although we recommend further research into extremely resistant isolates. For isolates within the typical range of clinical MICs, reexamination of the Etest interpretation of susceptible and nonsusceptible categories would likely allow for successful transition from agar dilution to the Etest. PMID:24554750

  4. Susceptibility testing of Propionibacterium acnes comparing agar dilution with E test.

    PubMed Central

    Smith, M A; Alperstein, P; France, K; Vellozzi, E M; Isenberg, H D

    1996-01-01

    Propionibacterium acnes has been identified as a significant agent of nosocomial infections, including endophthalmitis. Data concerning susceptibility of P. acnes to newer beta-lactam antibiotics and fluoroquinolones are limited. Recent reports suggest that quinolones have activity against these organisms sufficient to warrant further study. We undertook a study to select appropriate antimicrobial agents for use in a rabbit model of P. acnes endophthalmitis. We compared the antibiotic susceptibilities of P. acnes by using the National Committee for Clinical Laboratory Standards method of agar dilution with the E test. Thirteen clinical isolates obtained from eye specimens and three American Type Culture Collection control strains were tested against 14 antibiotics. All the clinical isolates were susceptible by both methods to piperacillin, piperacillin-tazobactam, ampicillin-sulbactam, ticarcillin-clavulanate, cefotaxime, cefotetan, ceftriaxone, cefoxitin, and imipenem in addition to clindamycin but were resistant to metronidazole. The clinical P. acnes isolates also displayed high-level susceptibility to ciprofloxacin, sparfloxacin, and ofloxacin. Almost all the P. acnes strains demonstrated E-test MICs within 2 dilutions of the MICs observed by the agar dilution method. Those few strains for which discrepancies were noted exhibited E-test susceptibilities three- to fivefold dilutions lower than the agar dilution method susceptibilities but only with ampicillin-sulbactam, ticarcillin-clavulanate, and/or clindamycin. On the basis of our study, all of clinical eye isolates were susceptible to these newer antimicrobial agents and the two methods demonstrated similar susceptibility patterns. PMID:8815076

  5. Evaluation of agar dilution and broth microdilution methods to determine the disinfectant susceptibility.

    PubMed

    Wu, Guoyan; Yang, Qianru; Long, Mei; Guo, Lijuan; Li, Bei; Meng, Yue; Zhang, Anyun; Wang, Hongning; Liu, Shuliang; Zou, Likou

    2015-11-01

    A variety of disinfectants have been widely used in veterinary hygiene, food industries and environments, which could induce the development of bacterial resistance to disinfectants. The methods used to investigate antimicrobial effects of disinfectant vary considerably among studies, making comparisons difficult. In this study, agar dilution and broth microdilution methods were used to compare the antimicrobial activities of four quaternary ammonium compounds (QACs) against foodborne and zoonotic pathogens. The potential relationship between the presence of QACs resistance genes and phenotypic resistance to QACs was also investigated. Our results indicated that the minimum inhibitory concentrations (MICs) determined by two methods might be different depended upon different QACs and bacteria applied. Regardless of the testing methods, Klebsiella pneumoniae was more tolerant among Gram-negative strains to four QACs, followed by Salmonella and Escherichia coli. The agreement between MICs obtained by the two methods was good, for benzalkonium chloride (78.15%), didecyldimethylammonium chloride (DDAC) (82.35%), cetylpyridinium chloride (CTPC) (97.48%) and cetyltrimethylammonium bromide (CTAB) (99.16%), respectively. Among all Gram-negative bacteria, 94.55% (n=52) of qacEΔ1-positive strains showed higher MICs (512 mg l(-1)) to CTAB. The qacEΔ1 gene was highly associated (P<0.05) with the high MICs of QACs (⩾512 mg l(-1)). In addition, DDAC remained as the most effective disinfectant against both Gram-positive and Gram-negative bacteria. This is the first study that compared the agar dilution and broth microdilution methods to assess the antimicrobial activity of QACs. The study demonstrated the need to standardize method that would be used in evaluating QACs antimicrobial properties in the future. PMID:25944532

  6. Modified agar dilution susceptibility testing method for determining in vitro activities of antifungal agents, including azole compounds.

    PubMed Central

    Yoshida, T; Jono, K; Okonogi, K

    1997-01-01

    In vitro activities of antifungal agents, including azole compounds, against yeasts were easily determined by using RPMI-1640 agar medium and by incubating the plates in the presence of 20% CO2. The end point of inhibition was clear by this method, even in the case of azole compounds, because of the almost complete inhibition of yeast growth at high concentrations which permitted weak growth of some Candida strains by traditional methods. MICs obtained by the agar dilution method were similar to those obtained by the broth dilution method proposed by the National Committee for Clinical Laboratory Standards. PMID:9174197

  7. Susceptibilities of genital mycoplasmas to the newer quinolones as determined by the agar dilution method.

    PubMed Central

    Kenny, G E; Hooton, T M; Roberts, M C; Cartwright, F D; Hoyt, J

    1989-01-01

    The increasing resistance of genital mycoplasmas to tetracycline poses a problem because tetracycline is one of the few antimicrobial agents active against Mycoplasma hominis, Ureaplasma urealyticum, chlamydiae, gonococci, and other agents of genitourinary-tract disease. Since the quinolones are a promising group of antimicrobial agents, the susceptibilities of M. hominis and U. urealyticum to the newer 6-fluoroquinolones were determined by the agar dilution method. Ciprofloxacin, difloxacin, and ofloxacin had good activity against M. hominis, with the MIC for 50% of isolates tested (MIC50) being 1 microgram/ml. Fleroxacin, lomefloxacin, pefloxacin, and rosoxacin had MIC50s of 2 micrograms/ml. Enoxacin, norfloxacin, and amifloxacin had MIC50s of 8 to 16 micrograms/ml, and cinoxacin and nalidixic acid were inactive (MIC50, greater than or equal to 256 micrograms/ml). Overall, the activities of 6-fluoroquinolones for ureaplasmas were similar to those for M. hominis, with MICs being the same or twofold greater. The most active 6-fluoroquinolones against ureaplasmas were difloxacin, ofloxacin, and pefloxacin, with MIC50s of 1 to 2 micrograms/ml. Ciprofloxacin was unusual in that the MIC50 for M. hominis was 1 microgram/ml, whereas the MIC50 for ureaplasmas was 8 micrograms/ml. Since the MIC50s for the most active quinolones approximate achievable concentrations in blood and urine, quinolones have promise in treating mycoplasmal infections. PMID:2712541

  8. National Committee for Clinical Laboratory Standards agar dilution susceptibility testing of anaerobic gram-negative bacteria.

    PubMed Central

    Brown, W J

    1988-01-01

    One hundred nine recent clinical isolates of anaerobic gram-negative bacteria were tested in triplicate by the National Committee for Clinical Laboratory Standards agar dilution procedure for their susceptibility to 32 antimicrobial agents. All isolates were inhibited by imipenem, but there were significant numbers of strains resistant to other beta-lactam drugs, and therefore the in vitro response to these antimicrobial agents cannot be predicted. This was particularly true for the bile-resistant or Bacteroides fragilis group. beta-Lactamase production was detected in 82% of the bacteroides with the nitrocefin test. Clavulanic acid combined with amoxicillin and ticarcillin and sulbactam combined with ampicillin resulted in synergistic activity against all beta-lactamase-positive organisms. Ceftizoxime was the most active of the cephalosporins. Two percent of the isolates were resistant to chloramphenicol and metronidazole. Clindamycin resistance was detected in 38% of the B. fragilis group, which is a marked increase from the 4% detected 10 years ago at this institution. PMID:3364956

  9. Comparison of E-test with agar dilution methods in testing susceptibility of N. gonorrhoeae to azithromycin.

    PubMed

    Yasin, R M; Suan, K A; Meng, C Y

    1997-05-01

    A single dose of a new antibiotic, azithromycin, has been shown to be effective in the treatment of uncomplicated Neisseria gonorrhoeae. A clinical study was conducted to assess the in vitro susceptibility of N gonorrhoeae to azithromycin and compare the reliability of results obtained using the new E-test methodology for determination of the minimum inhibitory concentration (MIC) of antibiotic with those obtained through the standard agar dilution method. 135 clinical isolates of N gonorrhoeae were obtained from patients attending hospital-based sexually transmitted disease clinics in five geographic locations in Malaysia. 76 of the isolates were penicillinase-producing N gonorrhoeae and 69 were high-level tetracycline-resistant N gonorrhoeae. All isolates were susceptible to azithromycin based on the susceptible MIC breakpoint of 2.0 mcg/ml. The MICs ranged from 0.0078-0.25 mcg/ml by agar dilution method and from 0.016-0.50 mcg/ml by E-test. Agreement between these two methods was 97.8%. The single-dose regime and good antigonococcal and antichlamydial activity of azithromycin make this antibiotic a suitable treatment choice. Moreover, the findings of this study suggest that the simpler, faster E-test is as reliable as the agar dilution method. Given the tendency of the antimicrobial susceptibility pattern of N gonorrhoeae to change rapidly, it is important to monitor MICs to detect the emergence of resistance. PMID:9153733

  10. Final report from the Committee on Antimicrobial Susceptibility Testing, Japanese Society of Chemotherapy, on the agar dilution method (2007).

    PubMed

    Nagayama, Ariaki; Yamaguchi, Keizo; Watanabe, Kunitomo; Tanaka, Masatoshi; Kobayashi, Intetsu; Nagasawa, Zenzo

    2008-10-01

    In 1968, the agar dilution method was developed as an independent Japanese method for measuring the minimal inhibitory concentration (MIC) of antimicrobial agents. As this method differed in a few respects from the MIC measurement methods used in other countries, it was revised in 1981, by a committee headed by Susumu Mitsuhashi, and the revised method (Chemotherapy 29:76-79, 1981) has been used since then. In 1979, an agar dilution method for measuring the MIC of anaerobes was developed by a committee chaired by Nozomu Kosakai (Chemotherapy 27:559-561, 1979). In 1990, a committee headed by Sachiko Goto approved a broth microdilution method for nonfastidious bacteria (Chemotherapy 38:102-105, 1990). Later, a committee headed by Atsushi Saito examined media that would be suitable for nonfastidious bacteria and fastidious bacteria, and they endeavored to prepare a broth microdilution method for anaerobic bacteria. In this context, a new broth microdilution method was proposed at the 40th Annual Meeting of the Japanese Society of Chemotherapy (JSC) in Nagoya in 1992, and the proposal was adopted as the standard JSC method after some modification (Chemotherapy 41: 183-189, 1993). The agar dilution method has remained unrevised for approximately 20 years. A proposal to review this method was recently made, and the 2007 Committee on Antimicrobial Susceptibility Testing was formed, comprising the JSC members listed below. Under the auspices of this committee, the method revised in 1981 was reviewed in comparison to the international standard method (Clinical and Laboratory Standards Institute [CLSI] method). PMID:18936894

  11. Determination of in vitro synergy for dual antimicrobial therapy against resistant Neisseria gonorrhoeae using Etest and agar dilution.

    PubMed

    Wind, Carolien M; de Vries, Henry J C; van Dam, Alje P

    2015-03-01

    In response to antimicrobial resistance of Neisseria gonorrhoeae to last-resort extended-spectrum cephalosporins, combination therapy of azithromycin+ceftriaxone is now recommended. Dual therapy can be effective to treat monoresistant strains as well as multidrug-resistant strains, preferably employing the effect of in vitro synergy. As reports on in vitro synergy of azithromycin+ceftriaxone in N. gonorrhoeae are conflicting, in this study an evaluation of this combination was performed using a cross-wise Etest method and agar dilution. Synergy was defined as a fractional inhibitory concentration index (FICI) of ≤0.5. To identify other dual treatment options for gonorrhoea, in vitro synergy was evaluated for 65 dual antimicrobial combinations using Etest. Azithromycin, cefixime, ceftriaxone, colistin, ertapenem, fosfomycin, gentamicin, minocycline, moxifloxacin, rifampicin, spectinomycin and tigecycline were screened for synergy in all possible combinations. No synergy or antagonism was found for any of the 65 combinations. The geometric mean FICI ranged from 0.82 to 2.00. The mean FICI of azithromycin+ceftriaxone was 1.18 (Etest) and 0.55 (agar dilution). The difference between both methods did not result in a difference in interpretation of synergy. Ceftriaxone-resistant strain F89 was tested in all combinations and no synergy was found for any of them. Most importantly, the ceftriaxone minimum inhibitory concentration of F89 was not decreased below the breakpoint with any concentration of azithromycin. PMID:25532741

  12. Inaccuracy of the Disk Diffusion Method Compared with the Agar Dilution Method for Susceptibility Testing of Campylobacter spp.

    PubMed Central

    Kotilainen, Pirkko; Puukka, Pauli; Nakari, Ulla-Maija; Siitonen, Anja; Eerola, Erkki; Huovinen, Pentti; Hakanen, Antti J.

    2012-01-01

    The agar dilution method has been standardized by the CLSI for the susceptibility testing of Campylobacter species, and according to these standards, the disk diffusion method should be used only in screening for macrolide and ciprofloxacin resistance. Nevertheless, the disk diffusion test is currently widely used, since it is easy to perform in clinical microbiology laboratories. In this study, the disk diffusion method was compared to the agar dilution method by analyzing the in vitro activities of seven antimicrobial agents against 174 Campylobacter strains collected in Finland between 2003 and 2008. Recommendations of the CLSI were followed using Mueller-Hinton agar plates with 5% of sheep blood. For each strain, the disk diffusion tests were performed two to four times. Of the 33 erythromycin-resistant strains (MIC, ≥16 μg/ml), 24 (73%) constantly showed a 6-mm erythromycin inhibition zone (i.e., no inhibition), while for seven strains the inhibition zone varied from 6 to 44 mm in repeated measurements. Among the 141 erythromycin-susceptible strains (MIC, <16 μg/ml), erythromycin inhibition zones varied between 6 and 61 mm. Of the 87 ciprofloxacin-resistant strains, 47 (54%) showed 6-mm inhibition zones, while 40 strains showed inhibition zones between 6 and 60 mm. Significant differences between the repetitions were observed in the disk diffusion for all antimicrobial agents and all strains except for the macrolide-resistant strains regarding the macrolides. For 17 (10%) strains, the variation in repeated measurements was substantial. These results show that the disk diffusion method may not be a reliable tool for the susceptibility testing of Campylobacter spp. Further studies are needed to assess whether the disk diffusion test could be improved or whether all susceptibilities of campylobacters should be tested using an MIC-based method. PMID:22075583

  13. Comparison of agar dilution and antibiotic gradient strip test with broth microdilution for susceptibility testing of swine Brachyspira species.

    PubMed

    Mirajkar, Nandita S; Gebhart, Connie J

    2016-03-01

    Production-limiting diseases in swine caused by Brachyspira are characterized by mucohemorrhagic diarrhea (B. hyodysenteriae and "B. hampsonii") or mild colitis (B. pilosicoli), while B. murdochii is often isolated from healthy pigs. Emergence of novel pathogenic Brachyspira species and strains with reduced susceptibility to commonly used antimicrobials has reinforced the need for standardized susceptibility testing. Two methods are currently used for Brachyspira susceptibility testing: agar dilution (AD) and broth microdilution (BMD). However, these tests have primarily been used for B. hyodysenteriae and rarely for B. pilosicoli. Information on the use of commercial susceptibility testing products such as antibiotic gradient strips is lacking. Our main objective was to validate and compare the susceptibility results, measured as the minimum inhibitory concentration (MIC), of 6 antimicrobials for 4 Brachyspira species (B. hyodysenteriae, "B. hampsonii", B. pilosicoli, and B. murdochii) by BMD and AD (tiamulin, valnemulin, lincomycin, tylosin, and carbadox) or antibiotic gradient strip (doxycycline) methods. In general, the results of a high percentage of all 4 Brachyspira species differed by ±1 log2 dilution or less by BMD and AD for tiamulin, valnemulin, lincomycin, and tylosin, and by BMD and antibiotic gradient strip for doxycycline. The carbadox MICs obtained by BMD were 1-5 doubling dilutions different than those obtained by AD. BMD for Brachyspira was quicker to perform with less ambiguous interpretation of results when compared with AD and antibiotic gradient strip methods, and the results confirm the utility of BMD in routine diagnostics. PMID:26965233

  14. Comparison of the MicroScan system and the agar dilution assay for Quinupristin/Dalfopristin susceptibility of Enterococcus faecium.

    PubMed

    Kim, Yang-Ree; Kim, Sang-Il; Hur, Ji-Ahn; Kim, Youn-Jeong; Wie, Seong-Heon; Park, Yeon-Joon; Kang, Moon-Won

    2007-01-01

    We compared the results of Quinupristin/Dalfopristin (Q/D) susceptibility tests by the Positive Combo Panel (Type 11) of the MicroScan Walk Away 96 analyzer (Dade Behring, Inc.) with those obtained by the reference agar dilution method. From September 2003 to August 2004, a total of 410 E. faecium isolates were obtained from clinical samples. Of these, 65 (15.9%) strains were non-susceptible, and 345 (84.1%) strains were susceptible to Q/D. We collected consecutively 65 Q/D non-susceptible E. faecium isolates (42 resistant, 23 intermediate), and randomly selected 32 Q/D susceptible E. faecium isolates using the MicroScan system. The minimal inhibitory concentrations (MICs) of Q/D, vancomycin, and teicoplanin were determined by the agar dilution method according to CLSI guidelines. The agreement rates between the two methods were 100% for Q/D-susceptible strains, 85.7% for Q/D-resistant strains, and 26.1% for Q/D-intermediate strains of E. faecium. The major error rate (S-->R) was 11.9%, and the minor error rate (S-->I) was 13.0%. No very major errors were found. We conclude that for MicroScan 'non-susceptible' test results for Q/D, it is necessary to confirm the result using a reference method. The Q/D-resistance rate was higher in glycopeptide-susceptible (78.0% for vancomycin, 82.0% for teicoplanin) than glycopeptide-resistant E. faecium (22.0% for vancomycin, 16.0% for teicoplanin). Further studies are needed to determine whether Q/D use in hospitals or virginiamycin use in animals, or other factors, are responsible for the high rates of glycopeptide-susceptible and Q/D-resistant E. faecium strains in Korea. PMID:17709691

  15. [Assessment of 2 automated microdilution techniques compared to an agar dilution method in determining sensitivity to fosfomycin in strains of carbapenem-resistant Pseudomonas aeruginosa].

    PubMed

    Gil-Romero, Yolanda; Regodón-Domínguez, Marta; Wilhelmi de Cal, Isabel; López-Fabal, Fátima; Gómez-Garcés, José Luis

    2016-01-01

    Carbapenems-resistance in Pseudomonas aeruginosa isolates has been widely reported. Fosfomycin has been shown to act synergistically with other antimicrobials. The agar dilution method was approved for susceptibility testing for fosfomycin and Pseudomonas aeruginosa. However, broth microdilution methods are the basis of systems currently used in clinical microbiology laboratories. The results of this study indicate that these methods are acceptable as susceptibility testing methods for fosfomycin against these organisms. PMID:26620604

  16. Antimicrobial susceptibility testing for Helicobacter pylori isolates from Brazilian children and adolescents: Comparing agar dilution, E-test, and disk diffusion

    PubMed Central

    Ogata, Silvio Kazuo; Gales, Ana Cristina; Kawakami, Elisabete

    2014-01-01

    Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p < 0.0001) and disk diffusion method (r=-0.6962, p < 0.0001). Clarithromycin presented moderate correlation to E-test (r = 0.6369, p < 0.0001) and disk diffusion method (r=−0.5656, p < 0.0001). Amoxicillin presented weak correlation to E-test (r = 0.3565, p = 0.0015) and disk diffusion (r=−0.3565, p = 0.0015). Tetracycline presented weak correlation with E-test (r = 0.2346, p = 0.04) and furazolidone to disk diffusion (r=−0.0288, p = 0.8038). E-test presented better agreement with gold standard. It is an easy and reliable method for Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors. PMID:25763052

  17. Correlation of agar dilution and VITEK2 system for detection of resistance to macrolides, lincosamides and pristinamycin among Staphylococcus aureus and Staphylococcus epidermidis: association with genotypes.

    PubMed

    Bémer, P; Juvin, M-E; Corvec, S; Ros, A; Drugeon, H

    2005-08-01

    The performance of the VITEK2 system was evaluated against the agar dilution reference procedure for testing susceptibility of Staphylococcus aureus and Staphylococcus epidermidis to macrolides, lincosamides and streptogramins (MLS). Eighty clinical isolates were selected according to their resistance phenotype and genotype. Results for erythromycin and clindamycin showed 100% agreement; results for lincomycin showed agreement of 78%, with one very major error and 17 minor errors; and results for pristinamycin showed agreement of 46%, with one major error and 43 minor errors. Most isolates resistant to lincomycin and streptogramin A (L SgAr phenotype) were falsely susceptible to lincomycin, and intermediately-resistant or resistant to pristinamycin, with the VITEK2 system. No resistance gene was detected. Most (80%) isolates resistant constitutively to MLS (MLS(r)BC phenotype) were falsely intermediately-resistant to pristinamycin with the VITEK2 system. The erm(A) gene was more common than erm(C) in MLS(r)BC strains. Resistance to pristinamycin alone (SgA SgB PTr phenotype), or associated with either lincomycin resistance (L SgA SgB PTr phenotype) or constitutive MLS(B) resistance (MLS(BC) SgA PTr phenotype), was well-characterised without discordant results. Resistance to pristinamycin was always associated with resistance to streptogramin A, encoded by the vga(A), vga(B), vgb(A) and vat(A) genes in association with the erm(A) or erm(C) genes. PMID:16008619

  18. Chryse Streak

    NASA Technical Reports Server (NTRS)

    2006-01-01

    6 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak created in the lee -- the downwind side -- of a crater in far eastern Chryse Planitia. The winds responsible for the formation of the streak blew from the upper right (northeast) to the lower left (southwest).

    Location near: 21.5oN, 27.4oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  19. Daedalia Streak

    NASA Technical Reports Server (NTRS)

    2005-01-01

    1 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dark wind streak formed in the lee of a crater in Daedalia Planum. The winds responsible for the streak blew from right (east) to left (west).

    Location near: 11.7oS, 136.4oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Summer

  20. [Angioid streaks].

    PubMed

    Matonti, F; Conrath, J

    2012-12-01

    Angioid streaks represent breaks in Bruch's membrane, appearing as dark or reddish radial streaks eminating from the optic disc. Usually asymptomatic, these streaks may develop neovascularisation and lead to a maculopathy with marked loss of vision. Some associations with systemic disease are classically described, especially pseudoxanthoma elasticum. This condition may involve cardiovascular complications. A mutation has been found in the ABCC6 gene, which encodes for a membrane transport protein involved in the synthesis of the extracellular matrix. Imaging allows for visualization of the extent of the streaks, and autofluorescence is particularly informative. Spectral domain OCT may also demonstrate early breaks in Bruch's membrane. Neovascular complications, previously responsible for inevitable visual impairment at some point after their occurrence, are now managed by intravitreal injections of anti-VEGFs with clear efficacity. The ophthalmologist must be aware of this condition, in order to guide the patient towards a systemic work-up if necessary, and also to insure quick and targeted treatment in the case of neovascular complications. PMID:23046745

  1. Wind Streaks

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 17 September 2003

    Bright wind streaks are present in the lee of craters and other obstacles in this image, located in Sinus Sabaeus, near the Martian equator. These streaks indicate that the local winds blow from the northeast (upper right in the image). The brightness of the streaks indicates that either bright material has been deposited in the lee of the craters, or that the surface has eroded preferentially in the lee of craters, exposing an underlying bright material. Because the streaks are bright regardless of the surrounding surface brightness, the first hypothesis most likely. The streaks probably all represent deposits of the same bright material that settled out of the atmosphere in the wind shelter provided by topographic peaks.

    Image information: VIS instrument. Latitude -6.3, Longitude 14.1 East (345.9 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the

  2. Disk Agar Diffusion Susceptibility Testing of Yeasts

    PubMed Central

    Saubolle, Michael A.; Hoeprich, Paul D.

    1978-01-01

    A disk agar diffusion method was developed for testing the susceptibility of rapidly growing yeasts in vitro. A totally defined, completely synthetic agar culture medium (synthetic amino acid medium, fungal) and clinical isolates of Candida spp. and Torulopsis glabrata were used. Turbidimetric adjustment of cell suspensions resulted in standard, reproducible inocula, which gave sharp, clear zones of inhibition when applied by an agar overlay method. Optimal disk loads were determined for amphotericin B, amphotericin B methyl ester, 5-fluorocytosine, clotrimazole, and miconazole. Disk potencies were stable over a 2-month period when stored in a vacuum desiccator at −30°C. Using an error ratebounded classification, the zones of inhibition were correlated with both broth dilution and agar dilution minimum inhibitory concentrations (MICs). With amphotericin B and amphotericin B methyl ester, all isolates were susceptible, yielding zone diameters which clustered within 5 mm. Overall correlations between zone diameters and broth dilution MICs with 5-fluorocytosine, miconazole, and clotrimazole were 97, 96, and 82% (excluding T. glabrata), respectively; correlations of zone diameters with agar dilution MICs were 96, 92, and 88%, respectively. Disk diffusion susceptibility testing of yeasts appears to be generally applicable. However, when results are equivocal, quantitative test methods should be used. PMID:568910

  3. Microchannel plate streak camera

    DOEpatents

    Wang, Ching L.

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  4. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1989-03-21

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras is disclosed. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1,000 KeV x-rays. 3 figs.

  5. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1984-09-28

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (uv to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 keV x-rays.

  6. Crater and Wind Streak

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-461, 23 August 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater with a bright wind streak in southern Acidalia Planitia. The streak is mostly likely a very thin coating of dust. The orientation of the streak indicates that the winds responsible for its formation and maintenance came from the northeast (upper right) and blew toward the lower left (southwest). The crater is located near 24.8oN, 39.1oW. The image covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  7. Crater with Streak

    NASA Technical Reports Server (NTRS)

    2005-01-01

    20 June 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater in the Memnonia region of Mars, around which has formed a wind streak. The bright streak is in the lee of the crater -- that is, it is on the crater's down-wind side. Thus, the winds responsible for the streak blew from the southeast (lower right).

    Location near: 6.7oS, 141.4oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  8. 21 CFR 582.7115 - Agar-agar.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Agar-agar. 582.7115 Section 582.7115 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7115 Agar-agar. (a) Product. Agar-agar. (b) Conditions of use. This substance is generally recognized as safe when used...

  9. 21 CFR 582.7115 - Agar-agar.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Agar-agar. 582.7115 Section 582.7115 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7115 Agar-agar. (a) Product. Agar-agar. (b) Conditions of use. This substance is generally recognized as safe when used...

  10. STREAK damping. Technical report

    SciTech Connect

    Baker, J.; Peyton, S.; Freiberg, H.

    1989-12-01

    This report documents a study aimed at improving the damping in STREAK. A form and value for an artificial viscosity is recommended which appears to control ringing and overshoots without overdamping.

  11. Wind Streak Changes

    NASA Technical Reports Server (NTRS)

    2004-01-01

    2 September 2004 This pair of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images shows changes in dark wind streak patterns that occurred between 5 April 1999 (image M00-00534) and 17 August 2004 (image R20-00901). Unlike the spaghetti-like streak patterns made by dust devils, these streaks all begin on their upwind ends as tapered forms that fan outward in the downwind direction, and they all indicate winds that blew from the same direction. In both cases, winds blew from the southeast (lower right) toward the northwest (upper left). These streaks and the small pedestal craters found among them occur in the Memnonia region of Mars near 5.9oS, 162.2oW. The 400 meter scale bar is about 437 yards long. Sunlight illuminates each scene from the upper left.

  12. Daedalia Wind Streak

    NASA Technical Reports Server (NTRS)

    2004-01-01

    21 January 2004 This January 2004 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dark wind streak in the lee of a small meteor impact crater in Daedalia Planum. The dominant winds responsible for this streak blew from the east (right). This picture is located near 17.1oS, 138.8oW, and covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the left.

  13. Wind Streak and Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    23 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak developed in the lee of a meteor impact crater in western Daedalia Planum. The dominant winds responsible for the streak blew from the bottom/lower right (southeast). The image is located near 9.9oS, 144.9oW. Sunlight illuminates the scene from the lower left; the picture covers an area 3 km (1.9 mi) wide.

  14. Frosty Wind Streaks

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-532, 2 November 2003

    As seasonal polar frosts sublime away each spring, winds may re-distribute some of the frost or move sediment exposed from beneath the frost. This action creates ephemeral wind streaks that can be used by scientists seeking to study the local circulation of the martian [missing text] surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of wind streaks created in subliming carbon dioxide frost. These dark streaks appear to conform to the shape of the slopes on which they occur, suggesting that slope winds play a dominant role in creating and orienting these streaks. This picture is located near 73.8oS, 305.7oW. The image is illuminated by sunlight from the upper left and covers an area 3 km (1.9 mi) wide. Winds responsible for the streaks generally blew from the bottom/right (south/southeast) toward the top/upper left (north/northwest).

  15. Huygens Wind Streak

    NASA Technical Reports Server (NTRS)

    2005-01-01

    19 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the results of wind action on the floor of the giant martian impact basin, Huygens. The large crater in this image has a wind streak on its lee side, pointing toward the lower right (southeast). Usually, a light-toned wind streak behind a crater on Mars will be composed of a thin veneer of dust that the wind was not able to erode because it was protected by the presence of the crater's raised rims. In this case, the streak is caused by something different -- by the fact that dark, windblown sand has not been able to accumulate behind the crater.

    Location near: 13.0oS, 303.7oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Spring

  16. Elysium Mons Wind Streak

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-556, 26 November 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak formed behind a meteor impact crater on the lower north flank of the volcano, Elysium Mons. Winds blow down the volcano slope, toward the northeast (toward upper right), causing a tail of uneroded dust to be captured behind the crater. Thin, filamentary dark streaks (resembling pencil scratches in this image) can be seen on the surface of the bright wind streak; these may have formed by disruption of surface dust by passing dust devils. This picture is located near 27.7oN, 212.7oW. The image covers an area 3 km (1.9 mi) wide, and is illuminated by sunlight from the left.

  17. Polar Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    30 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image of dunes in the martian north polar region is important because it shows one of the highest northern latitude views of streaks thought to be made by passing dust devils. The dark, thin, filamentary streaks on the dunes and on the adjacent plains were probably formed by dust devils. The dunes occur near 76.6oN, 62.7oW. Dust devil streaks are observed on Mars at very high latitudes, such as this, all the way down to the equator. They are also seen at all elevations, from the deepest parts of the Hellas Basin to the summit of Olympus Mons. This picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  18. Wind Streaks Among Flows

    NASA Technical Reports Server (NTRS)

    2004-01-01

    17 December 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark wind streaks formed by removal of a thin veneer of bright dust covering small craters and lava flow surfacesnorthwest of Olympus Mons near 28.4oN, 129.8oW. Streak orientations indicate that the responsible winds blew from the east/southeast (right/lower right) toward the west/northwest (left/upper left). The image covers an area about 3 km (1.9 mi) wide. Sunlight illuminates thescene from the lower left.

  19. Devil-Streaked Plain

    NASA Technical Reports Server (NTRS)

    2006-01-01

    19 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark streaks on a plain south of the giant impact basin, Hellas Planitia. The streaks map the routes traveled by dozens of individual southern spring and early summer dust devils.

    Location near: 68.4oS, 296.1oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  20. Streak camera receiver definition study

    NASA Technical Reports Server (NTRS)

    Johnson, C. B.; Hunkler, L. T., Sr.; Letzring, S. A.; Jaanimagi, P.

    1990-01-01

    Detailed streak camera definition studies were made as a first step toward full flight qualification of a dual channel picosecond resolution streak camera receiver for the Geoscience Laser Altimeter and Ranging System (GLRS). The streak camera receiver requirements are discussed as they pertain specifically to the GLRS system, and estimates of the characteristics of the streak camera are given, based upon existing and near-term technological capabilities. Important problem areas are highlighted, and possible corresponding solutions are discussed.

  1. Craters and Streaks

    NASA Technical Reports Server (NTRS)

    2006-01-01

    1 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two impact craters of nearly equal size, plus their associated wind streaks. These occur in far eastern Chryse Planitia. The wind streaks point toward the southwest (lower left), indicating that the responsible winds blew from the northeast. One of the two craters is shallower than the other, and has a suite of large, windblown ripples on its floor. The shallower crater with the ripples is probably older than the other, deeper crater.

    Location near: 20.6oN, 30.1oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  2. Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2005-01-01

    27 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a plethora of dark streaks created by spring and summer dust devil activity in Argyre Planitia.

    Location near: 64.9oS, 8.3oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  3. Automatic Surface Inoculation of Agar Trays1

    PubMed Central

    Wilkins, Judd R.; Mills, Stacey M.; Boykin, Elizabeth H.

    1972-01-01

    A machine is described which automatically inoculates a plastic tray containing agar media with a culture by use of either a conventional inoculating loop or a cotton swab. Isolated colonies were obtained with an inoculating loop when a heavy inoculum (109 cells/ml) was used or with a cotton swab when a light inoculum (ca. 104 cells/ml) was used. Trays containing combinations of differential or selective media were used to (i) separate mixtures of gram-positive and gram-negative bacteria, (ii) facilitate isolation of organisms from clinical specimens, and (iii) compare colony growth characteristics of pure cultures. The design of the machine is simple, it is easy to use, and it relieves the operator from the manual task of streaking cultures. Images PMID:16349943

  4. Triton's streaks as windblown dust

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Chyba, Christopher

    1990-01-01

    Explanations for the surface streaks observed by Voyager 2 on Triton's southern hemisphere are discussed. It is shown that, despite Triton's tenuous atmosphere, low-cohesion dust trains with diameters of about 5 micron or less may be carried into suspension by aeolian surface shear stress, given expected geostrophic wind speeds of about 10 m/s. For geyser-like erupting dust plumes, it is shown that dust-settling time scales and expected wind velocities can produce streaks with length scales in good agreement with those of the streaks. Thus, both geyserlike eruptions or direct lifting by surface winds appear to be viable mechanisms for the origin of the streaks.

  5. Daedalia Planum Wind Streak

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-332, 16 April 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a complex streak formed by deposition and erosion of sediment by wind in the lee of an impact crater in western Daedalia Planum. The winds needed to create this feature blew from the southeast (from the lower right). The picture covers an area 3 km (1.9 mi) wide near 10.1oS, 133.7oW. Sunlight illuminates the scene from the upper left.

  6. Bright Devil Streaks

    NASA Technical Reports Server (NTRS)

    2005-01-01

    4 March 2005 In honor of Giovanni V. Schiaparelli's 170th birthday, we present this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image showing light-toned dust devil streaks on the southern floor of Schiaparelli Crater.

    Location near: 5.3oS, 343.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

  7. Bright Streak on Amalthea

    NASA Technical Reports Server (NTRS)

    2000-01-01

    These two images of Jupiter's small, irregularly shaped moon Amalthea, obtained by the camera onboard NASA's Galileo spacecraft in August 1999(left) and November 1999 (right), form a 'stereo pair' that helps scientists determine this moon's shape and the topography of its surface features. Features as small as 3.8 kilometers (2.4 miles) across can be resolved in these images, making them among the highest-resolution images ever taken of Amalthea.

    The large impact crater visible in both images, near the right-hand edge of Amalthea's disk, is about 40 kilometers (about 29 miles) across; two ridges, tall enough to cast shadows, extend from the top of the crater in a V-shape reminiscent of a 'rabbit ears' television antenna. To the left of these ridges, in the top center portion of Amalthea's disk, is a second large impact crater similar in size to the first crater. To the left of this second crater is a linear 'streak' of relatively bright material about 50 kilometers (31 miles) long. In previous spacecraft images of Amalthea taken from other viewing directions, this bright feature was thought to be a small, round, bright 'spot' and was given the name Ida. These new images reveal for the first time that Ida is actually a long, linear 'streak.' This bright streak may represent material ejected during the formation of the adjacent impact crater, or it may just mark the crest of a local ridge. Other patches of relatively bright material can be seen elsewhere on Amalthea's disk, although none of these other bright spots has Ida's linear shape.

    In both images, sunlight is coming from the left and north is approximately up. Note that the north pole of Amalthea is missing in the right-hand image (it was cut off by the edge of the camera frame). The bright streak, Ida, is on the side of the moon that faces permanently away from Jupiter, and the crater near the right-hand edge of the disk is in the center of Amalthea's leading side (the side of the moon that 'leads

  8. Streaking into Middle School Science: The Dell Streak Pilot Project

    ERIC Educational Resources Information Center

    Austin, Susan Eudy

    2012-01-01

    A case study is conducted implementing the Dell Streak seven-inch android device into eighth grade science classes of one teacher in a rural middle school in the Piedmont region of North Carolina. The purpose of the study is to determine if the use of the Dell Streaks would increase student achievement on standardized subject testing, if the…

  9. Light and Dark Slope Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    21 July 2004 Dark slope streaks are a common feature on slopes thickly-mantled by dust, especially in the Tharsis, Arabia, and western Amazonis regions of Mars. Less common are light-toned slope streaks, which often occur in the same area as dark streaks. They are most common in Arabia Terra, and some are shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. Slope streaks are probably the result of sudden avalanches of extremely dry dust. The behavior of the avalanching dust is somewhat fluid-like, and new streaks have been observed to form over intervals of a few months to a Mars year. This image is located near 13.4oN, 340.3oW, and covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  10. Cerberus Wind Streaks

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 6 May 2002) The Science Cerberus is a dark region on Mars that has shrunk down from a continuous length of about 1000 km to roughly three discontinuous spots a few 100 kms in length in less than 20 years. There are two competing processes at work in the Cerberus region that produce the bright and dark features seen in this THEMIS image. Bright dust settles out of the atmosphere, especially after global dust storms, depositing a layer just thick enough to brighten the dark surfaces. Deposition occurs preferentially in the low wind 'shadow zones' within craters and downwind of crater rims, producing the bright streaks. The direction of the streaks clearly indicates that the dominant winds come from the northeast. Dust deposition would completely blot out the dark areas if it were not for the action of wind-blown sand grains scouring the surface and lifting the dust back into the atmosphere. Again, the shadow zones are protected from the blowing sand, preserving the bright layer of dust. Also visible in this image are lava flow features extending from the flanks of the huge Elysium volcanoes to the northwest. Two shallow channels and a raised flow lobe are just barely discernable. The lava channel in the middle of the image crosses the boundary of the bright and dark surfaces without any obvious change in its morphology. This demonstrates that the bright dust layer is very thin in this location, perhaps as little as a few millimeters. The Story Mars is an ever-changing land of spectacular contrasts. This THEMIS image shows the Cerberus region of Mars, a dark area located near the Elysium volcanoes and fittingly named after the three-headed, dragon-tailed dog who guards the door of the underworld. Two opposing processes are at work here: a thin layer of dust falling from the atmosphere and/or dust storms creating brighter surface areas (e.g. the top left portion of this image) and dust being scoured away by the action of the Martian wind disturbing the sand

  11. Electro-osmosis in gels: Application to Agar-Agar

    NASA Astrophysics Data System (ADS)

    Cherblanc, Fabien; Boscus, Jérôme; Bénet, Jean-Claude

    2008-10-01

    Widely used in food- and bio-engineering as a reference material, Agar-Agar gel is the focus of an experimental investigation concerning the electro-osmosis phenomenon. After presenting the experimental methods, one trial is discussed in detail. A fair reproducibility of results is obtained, and the averaged electro-osmotic permeability is provided. This value lies in the range generally measured on various kind of soils, even if Agar-Agar gel does not share any micro-structural characteristics with soils. To cite this article: F. Cherblanc et al., C. R. Mecanique 336 (2008).

  12. Comparison of Streak Tube Performance

    SciTech Connect

    Lerche, R A; Andrews, D S; Bell, P M; Griffiths, R L; Huey, A W; McDonald, J W; de Dios, G V

    2004-11-04

    The performance of four streak tubes in six streak camera configurations is reported. Evaluations were made as part of a search for a streak tube to replace the obsolete RCA C73435 used in the ICF Program's optical streak cameras. Characteristics measured include linearity, spatial and temporal resolution, line-spread function, contrast transfer ratio (CTR), and dynamic range. Tubes evaluated are the RCA C73435, Photonis P510, Photek ST-Y, and Hamamatsu N8059. The RCA C73435 was evaluated in three camera configurations: large format CCD coupled directly to the streak tube, CCD directly coupled to an image intensifier tube (IIT), and the original configuration with a smaller CCD lens coupled to the IIT output. The Photonis and Photek tubes were characterized in configurations where they were directly coupled to large format CCDs. Optimum spatial resolution is achieved when the IIT is removed. Maximum dynamic range requires a configuration where a single photoelectron from the photocathode produces a signal that is {approx}5 times the CCD read noise. The Photonis P510 tube with the E2V CCD forms a well-optimized streak camera system.

  13. Characterization of Dark Streaks on Martian Slopes

    NASA Astrophysics Data System (ADS)

    Fenton, L. K.; Danielson, G. E.; Albee, A.; MGS MOC Science Team

    1998-09-01

    The narrow angle MOC images from the Mars Global Surveyor (MGS) show dozens of examples of dark streaks on Martian hillsides that may be indicative of fluid flow. In many cases multiple streaks seem to initiate from a narrow layer near the tops of steep slopes. They appear from these layers as narrow features that quickly broaden and then either remain the same width downhill or narrow and disappear. The largest streak observed to date is approximately 2 km in length and 100 m in width. MOLA data is not yet available to determine the slope down the length of the streaks. The lack of variation in brightness downhill and across the streaks shows that the formation of each streak occurred quickly. The streaks are widely distributed globally, but seem to be confined to layered materials. The streaks' characteristics show not only that the material forming them moved rapidly downslope but also that the streak material originated within the nearby bedrock. Change in brightness from one streak to another provides relative streak ages, assuming that dust infall causes an increase in streak albedo. The dark streaks are caused by a process that appears similar to fluid flow at the resolution of the MOC images. Possible causes of the streaks are water flow, lava flow, and debris flow. Our results are not yet conclusive as to the origins of the dark streaks, but we narrow the range of possible formation processes.

  14. 21 CFR 184.1115 - Agar-agar.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Agar-agar. 184.1115 Section 184.1115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of...

  15. 21 CFR 184.1115 - Agar-agar.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Agar-agar. 184.1115 Section 184.1115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS §...

  16. 21 CFR 184.1115 - Agar-agar.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Agar-agar. 184.1115 Section 184.1115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1115...

  17. 21 CFR 184.1115 - Agar-agar.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Agar-agar. 184.1115 Section 184.1115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of...

  18. 21 CFR 184.1115 - Agar-agar.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Agar-agar. 184.1115 Section 184.1115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD... ingredient meets the specifications of the “Food Chemicals Codex,” 3d Ed. (1981), p. 11, which...

  19. Automatic agar tray inoculation device

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.; Mills, S. M.

    1972-01-01

    Automatic agar tray inoculation device is simple in design and foolproof in operation. It employs either conventional inoculating loop or cotton swab for uniform inoculation of agar media, and it allows technician to carry on with other activities while tray is being inoculated.

  20. Streak camera dynamic range optimization

    SciTech Connect

    Wiedwald, J.D.; Lerche, R.A.

    1987-09-01

    The LLNL optical streak camera is used by the Laser Fusion Program in a wide range of applications. Many of these applications require a large recorded dynamic range. Recent work has focused on maximizing the dynamic range of the streak camera recording system. For our streak cameras, image intensifier saturation limits the upper end of the dynamic range. We have developed procedures to set the image intensifier gain such that the system dynamic range is maximized. Specifically, the gain is set such that a single streak tube photoelectron is recorded with an exposure of about five times the recording system noise. This ensures detection of single photoelectrons, while not consuming intensifier or recording system dynamic range through excessive intensifier gain. The optimum intensifier gain has been determined for two types of film and for a lens-coupled CCD camera. We have determined that by recording the streak camera image with a CCD camera, the system is shot-noise limited up to the onset of image intensifier nonlinearity. When recording on film, the film determines the noise at high exposure levels. There is discussion of the effects of slit width and image intensifier saturation on dynamic range. 8 refs.

  1. The Rochester Optical Streak System

    NASA Astrophysics Data System (ADS)

    Jaanimagi, P. A.; Boni, R.; Keck, R. L.; Donaldson, W. R.; Meyerhofer, D. D.

    2004-11-01

    A modern, self-calibrating, remotely controlled streak camera platform capable of accepting a variety of different streak tubes has been developed. Our current systems include P510, P820, and PJX streak tubes with both S-1 and S-20 photocathodes. The input may be either fiber delivery or free-space propagation and is relayed to the photocathode with an achromatic Offner triplet. Calibration functions include autofocus of the input and electron optics, geometric distortion and flat-field correction, system gain, and linearity. The four remotely selectable sweep speeds are calibrated with an on-board optical comb generator. The recording system is a fiber-coupled back-illuminated CCD camera. We will present data illustrating the many features of the ROSS camera as applied to laser and plasma diagnostics. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-92SF19460.

  2. Circular Scan Streak Tube Development

    NASA Technical Reports Server (NTRS)

    Nevin, S.

    1980-01-01

    A streak tube having circular scan was designed, built and tested. Continuous circular scan, easily derived from out of phase sine waves applied to the conventional deflection plates, permits the timing of pulses traveling long baselines. At the tube's output a circular array of 720 elements is scanned to provide 30 to 40 picosecond resolution. Initial difficulties with electron bombarded silicon arrays were circumvented by using microchannel plates within the streak tube to provide the needed electronic amplification and digital sensitivity and coupling the 720 element arrays to the electron beam by means of a phosphor on a fiber optics. Two ceramic body tubes with S-20 photocathodes were tested and delivered.

  3. Streaking into middle school science: The Dell Streak pilot project

    NASA Astrophysics Data System (ADS)

    Austin, Susan Eudy

    A case study is conducted implementing the Dell Streak seven-inch android device into eighth grade science classes of one teacher in a rural middle school in the Piedmont region of North Carolina. The purpose of the study is to determine if the use of the Dell Streaks would increase student achievement on standardized subject testing, if the Streak could be used as an effective instructional tool, and if it could be considered an effective instructional resource for reviewing and preparing for the science assessments. A mixed method research design was used for the study to analyze both quantitative and qualitative results to determine if the Dell Streaks' utilization could achieve the following: 1. instructional strategies would change, 2. it would be an effective instructional tool, and 3. a comparison of the students' test scores and benchmark assessments' scores would provide statistically significant difference. Through the use of an ANOVA it was determined a statistically significant difference had occurred. A Post Hoc analysis was conducted to identify where the difference occurred. Finally a T-test determined was there was no statistically significance difference between the mean End-of-Grade tests and four quarterly benchmark scores of the control and the experimental groups. Qualitative research methods were used to gather results to determine if the Streaks were an effective instructional tool. Classroom observations identified that the teacher's teaching styles and new instructional strategies were implemented throughout the pilot project. Students had an opportunity to complete a questionnaire three times during the pilot project. Results revealed what the students liked about using the devices and the challenges they were facing. The teacher completed a reflective questionnaire throughout the pilot project and offered valuable reflections about the use of the devices in an educational setting. The reflection data supporting the case study was drawn

  4. Slope Streaks in Terra Sabaea

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1 Click on image for larger version

    This HiRISE image shows the rim of a crater in the region of Terra Sabaea in the northern hemisphere of Mars.

    The subimage (figure 1) is a close-up view of the crater rim revealing dark and light-toned slope streaks. Slope streak formation is among the few known processes currently active on Mars. While their mechanism of formation and triggering is debated, they are most commonly believed to form by downslope movement of extremely dry sand or very fine-grained dust in an almost fluidlike manner (analogous to a terrestrial snow avalanche) exposing darker underlying material.

    Other ideas include the triggering of slope streak formation by possible concentrations of near-surface ice or scouring of the surface by running water from aquifers intercepting slope faces, spring discharge (perhaps brines), and/or hydrothermal activity.

    Several of the slope streaks in the subimage, particularly the three longest darker streaks, show evidence that downslope movement is being diverted around obstacles such as large boulders. Several streaks also appear to originate at boulders or clumps of rocky material.

    In general, the slope streaks do not have large deposits of displaced material at their downslope ends and do not run out onto the crater floor suggesting that they have little reserve kinetic energy. The darkest slope streaks are youngest and can be seen to cross cut and superpose older and lighter-toned streaks. The lighter-toned streaks are believed to be dark streaks that have lightened with time as new dust is deposited on their surface.

    Observation Geometry Image PSP_001808_1875 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Dec-2006. The complete image is centered at 7.4 degrees latitude, 47.0 degrees East longitude. The range to the target site was 272.1 km

  5. Fastidious anaerobe agar compared with Wilkins-Chalgren agar, brain heart infusion agar, and brucella agar for susceptibility testing of Fusobacterium species.

    PubMed

    Brazier, J S; Goldstein, E J; Citron, D M; Ostovari, M I

    1990-11-01

    Fastidious anaerobe agar supported the growth of 82 strains of fusobacteria better than brain heart infusion agar, brucella agar, and Wilkins-Chalgren agar. Fastidious anaerobe agar showed less hazing and fewer tailing endpoints with beta-lactam antibiotics. Whole-blood supplementation improved the performance of all media. Wilkins-Chalgren agar without blood failed to support the growth of 17% of the strains. All Fusobacterium ulcerans strains were resistant to clindamycin. PMID:2073122

  6. Dark streaks on talus slopes, Mars

    NASA Astrophysics Data System (ADS)

    Ferguson, H. M.; Lucchitta, B. K.

    1984-04-01

    High-resolution pictures of talus slopes on Mars show small, dark streaks that characteristically widen downward. These streaks are different from the thin and even streaks of various albedos that stream from cliffs on talus slopes, but gradations between the two streak types occur and not all streaks can be classified with confidence. In order to study the nature and origin of the small, widening, dark streaks, all Viking pictures with a resolution of less than 100 m/pixel were surveyed. To date several hundred streaks were located, but only few are of high enough resolution to be confidently identified as widening downwards. The approximate dimensions of the streaks were measured and their shapes, numbers, position, and spacing on slopes were noted. They were plotted on a topographic map, and their relation to topography, geologic units, and regions of distinct thermal inertia and albedo were studied. Also noted was the season at which images containing streaks were acquired and the direction of illumination. Albedo measurements are in progress. Several streaks can be seen stereoscopically, but none are observed on color images. The observation of small dark streaks on talus slopes on Mars is compatible with an interpretation of their origin as eruptions of small masses of wet debris in places where steep walls intersect aquifers or where seasonal equatorial warming permits the local melting of ground ice.

  7. Wind vs. Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    22 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image presents a fine illustration of the difference between streaks made by dust devils and streaks made by wind gusts. Dust devils are usually solitary, spinning vortices. They resemble a tornado, or the swirling motion of a familiar, Tasmanian cartoon character. Wind gusts, on the other hand, can cover a larger area and affect more terrain at the same time. The dark, straight, and parallel features resembling scrape marks near the right/center of this image are thought to have been formed by a singular gust of wind, whereas the more haphazard dark streaks that crisscross the scene were formed by dozens of individual dust devils, acting at different times. This southern summer image is located in Noachis Terra near 67.0oS, 316.2oW. Sunlight illuminates the scene from the upper left; the picture covers an area 3 km (1.9 mi) wide.

  8. 48 CFR 401.371 - AGAR Advisories.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false AGAR Advisories. 401.371... ACQUISITION REGULATION SYSTEM Agency Acquisition Regulations 401.371 AGAR Advisories. The SPE may issue AGAR Advisories, consistent with the policies of the FAR and the AGAR, for the following purposes: (a)...

  9. 48 CFR 401.371 - AGAR Advisories.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false AGAR Advisories. 401.371... ACQUISITION REGULATION SYSTEM Agency Acquisition Regulations 401.371 AGAR Advisories. The SPE may issue AGAR Advisories, consistent with the policies of the FAR and the AGAR, for the following purposes: (a)...

  10. Measurement of width and intensity of particle streaks in turbulent flows

    NASA Astrophysics Data System (ADS)

    Håkansson, Karl M. O.; Kvick, Mathias; Lundell, Fredrik; Prahl Wittberg, Lisa; Söderberg, L. Daniel

    2013-06-01

    Fibre streaks are observed in experiments with fibre suspensions in a turbulent half-channel flow. The preferential concentration methods, most commonly used to quantify preferential particle concentration, are in one dimension found to be concentration dependent. Two different new streak quantification methods are evaluated, one based on Voronoi analysis and the other based on artificial particles with an assigned fixed width. The width of the particle streaks and a measure of the intensity of the streaks, i.e. streakiness, are sought. Both methods are based on the auto-correlation of a signal, generated by summing images in the direction of the streaks. Common for both methods is a severe concentration dependency, verified in experiments keeping the flow conditions constant while the (very dilute) concentration of fibres is altered. The fixed width method is shown to be the most suitable method, being more robust and less computationally expensive. By assuming the concentration dependence to be related to random noise, an expression is derived, which is shown to make the streak width and the streakiness independent of the concentration even at as low concentrations as 0.05 particles per pixel column in an image. The streakiness is obtained by applying an artificial particle width equal to 20 % of the streak width. This artificial particle width is in this study found to be large enough to smoothen the correlation without altering the streakiness nor the streak width. It is concluded that in order to make quantitative comparisons between different experiments or simulations, the evaluation has to be performed with care and be very well documented.

  11. Black streak root rot of lentil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black streak root rot of lentil is caused by the soil borne fungus Thielaviopsis basicola. The pathogen is widespread. The disease shows symptoms of black streaking on root, and stunted plants. The disease is favored by cool and moist weather. Management of the disease rely on avoiding fields wi...

  12. Earth and planetary aeolian streaks: A review

    NASA Astrophysics Data System (ADS)

    Cohen-Zada, Aviv Lee; Blumberg, Dan Gabriel; Maman, Shimrit

    2016-03-01

    Wind streaks are abundant aeolian features that have been observed on planetary surfaces by remote sensing means. They have been widely studied, particularly on Mars and Venus and to a much lesser extent on Earth. In imagery, these streaks appear as elongated features that are easily distinguishable from their surroundings. Geomorphologically, these streaks have, thus far, been interpreted as the presence or absence of small loose particles on the surface, deposited or eroded, respectively, by wind. However, the use of different (optical and radar) remote-sensing tools to study wind streaks has led to uncertain interpretations of these features and has hindered their geomorphological definition. Since wind streaks indicate the prevailing wind direction at the time of their formation, they may be used to map near-surface winds and to estimate atmospheric circulation patterns. The aim of this article is to review the main studies focusing on wind streaks and to present the most up-to-date knowledge on this topic. Moreover, a new perspective for wind streak research is suggested: As 'wind streak' is a collective term for a variety of aeolian features that when viewed from above appear as distinctive albedo surface patterns, we suggest that the term should not be used to refer to a geomorphological feature. Since the definition of wind streaks is constrained to remote sensing rather than to geomorphology and is affected by the inherent biases of remote sensing methods, we suggest that 'wind streaks' should be used as a collective term for aeolian surfaces that are discernable from above as bright and dark patterns due to alterations in the characteristics of the surface or to the presence of bedforms. To better understand the mechanisms, time-frames, climate compatibility of wind streaks and the influences of remote sensing on their appearance, we have compiled a new database containing more than 2,900 Earth wind streaks. A comprehensive study of these Earth wind

  13. Wind Streaks on Earth; Exploration and Interpretation

    NASA Astrophysics Data System (ADS)

    Cohen-Zada, Aviv Lee; Blumberg, Dan G.; Maman, Shimrit

    2015-04-01

    Wind streaks, one of the most common aeolian features on planetary surfaces, are observable on the surface of the planets Earth, Mars and Venus. Due to their reflectance properties, wind streaks are distinguishable from their surroundings, and they have thus been widely studied by remote sensing since the early 1970s, particularly on Mars. In imagery, these streaks are interpreted as the presence - or lack thereof - of small loose particles on the surface deposited or eroded by wind. The existence of wind streaks serves as evidence for past or present active aeolian processes. Therefore, wind streaks are thought to represent integrative climate processes. As opposed to the comprehensive and global studies of wind streaks on Mars and Venus, wind streaks on Earth are understudied and poorly investigated, both geomorphologically and by remote sensing. The aim of this study is, thus, to fill the knowledge gap about the wind streaks on Earth by: generating a global map of Earth wind streaks from modern high-resolution remotely sensed imagery; incorporating the streaks in a geographic information system (GIS); and overlaying the GIS layers with boundary layer wind data from general circulation models (GCMs) and data from the ECMWF Reanalysis Interim project. The study defines wind streaks (and thereby distinguishes them from other aeolian features) based not only on their appearance in imagery but more importantly on their surface appearance. This effort is complemented by a focused field investigation to study wind streaks on the ground and from a variety of remotely sensed images (both optical and radar). In this way, we provide a better definition of the physical and geomorphic characteristics of wind streaks and acquire a deeper knowledge of terrestrial wind streaks as a means to better understand global and planetary climate and climate change. In a preliminary study, we detected and mapped over 2,900 wind streaks in the desert regions of Earth distributed in

  14. Orbital objects detection algorithm using faint streaks

    NASA Astrophysics Data System (ADS)

    Tagawa, Makoto; Yanagisawa, Toshifumi; Kurosaki, Hirohisa; Oda, Hiroshi; Hanada, Toshiya

    2016-02-01

    This study proposes an algorithm to detect orbital objects that are small or moving at high apparent velocities from optical images by utilizing their faint streaks. In the conventional object-detection algorithm, a high signal-to-noise-ratio (e.g., 3 or more) is required, whereas in our proposed algorithm, the signals are summed along the streak direction to improve object-detection sensitivity. Lower signal-to-noise ratio objects were detected by applying the algorithm to a time series of images. The algorithm comprises the following steps: (1) image skewing, (2) image compression along the vertical axis, (3) detection and determination of streak position, (4) searching for object candidates using the time-series streak-position data, and (5) selecting the candidate with the best linearity and reliability. Our algorithm's ability to detect streaks with signals weaker than the background noise was confirmed using images from the Australia Remote Observatory.

  15. Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The south polar region of Mars is covered every year by a layer of carbon dioxide ice. In a region called the 'cryptic terrain,' the ice is translucent and sunlight can penetrate through the ice to warm the surface below.

    The ice layer sublimates (evaporates) from the bottom. The dark fans of dust seen in this image come from the surface below the layer of ice, carried to the top by gas venting from below. The translucent ice is 'visible' by virtue of the effect it has on the tone of the surface below, which would otherwise have the same color and reflectivity as the fans.

    Bright streaks in this image are fresh frost. The CRISM team has identified the composition of these streaks to be carbon dioxide.

    Observation Geometry Image PSP_003113_0940 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 26-Mar-2007. The complete image is centered at -85.8 degrees latitude, 106.0 degrees East longitude. The range to the target site was 244.9 km (153.0 miles). At this distance the image scale is 49.0 cm/pixel (with 2 x 2 binning) so objects 147 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 06:20 PM and the scene is illuminated from the west with a solar incidence angle of 79 degrees, thus the sun was about 11 degrees above the horizon. At a solar longitude of 207.6 degrees, the season on Mars is Northern Autumn.

  16. Electro-optic Phase Grating Streak Spectrometer

    SciTech Connect

    Goldin, F. J.

    2012-08-02

    The electro-optic phase grating streak spectrometer (EOPGSS) generates a time-resolved spectra equivalent to that obtained with a conventional spectrometer/streak camera combination, but without using a streak camera (by far the more expensive and problematic component of the conventional system). The EOPGSS is based on a phase, rather than an amplitude grating. Further, this grating is fabricated of electro-optic material such as, for example, KD*P, by either etching grooves into an E-O slab, or by depositing lines of the E-O material onto an optical flat. An electric field normal to the grating alters the material’s index of refraction and thus affects a shift (in angle) of the output spectrum. Ramping the voltage streaks the spectrum correspondingly. The streak and dispersion directions are the same, so a second (static, conventional) grating disperses the spectrum in the orthogonal direction to prevent different wavelengths from “overwriting” each other. Because the streaking is done by the grating, the streaked output spectrum is recorded with a time-integrating device, such as a CCD. System model, typical design, and performance expectations will be presented.

  17. Crystal formation in furunculosis agar

    USGS Publications Warehouse

    Bullock, G.L.; Ross, A.J.

    1964-01-01

    SINCE ITS INTRODUCTION SOME MONTHS AGO, FURUNCULOSIS AGAR has been employed in the diagnosis of suspect furunculosis and also as a general purpose medium. During our work with this medium we have noticed discrete "colonies," of crystalline material, which very closely resemble microbial colonies. These crystal colonies are compact and appear on both the surface and subsurface; they occur in inoculated slants and plates incubated for long periods (2 to 3 weeks), as well as in uninoculated stored medium. As the crystal colonies could be confusing to workers using this medium, we decided to attempt to identify them and also to determine whether storage conditions and different lots of medium affect crystal formation.

  18. Compact Optical Technique for Streak Camera Calibration

    SciTech Connect

    Curt Allen; Terence Davies; Frans Janson; Ronald Justin; Bruce Marshall; Oliver Sweningsen; Perry Bell; Roger Griffith; Karla Hagans; Richard Lerche

    2004-04-01

    The National Ignition Facility is under construction at the Lawrence Livermore National Laboratory for the U.S. Department of Energy Stockpile Stewardship Program. Optical streak cameras are an integral part of the experimental diagnostics instrumentation. To accurately reduce data from the streak cameras a temporal calibration is required. This article describes a technique for generating trains of precisely timed short-duration optical pulses that are suitable for temporal calibrations.

  19. Performance of CHROMAGAR candida and BIGGY agar for identification of yeast species

    PubMed Central

    Yücesoy, Mine; Marol, Serhat

    2003-01-01

    Background The importance of identifying the pathogenic fungi rapidly has encouraged the development of differential media for the presumptive identification of yeasts. In this study two differential media, CHROMagar Candida and bismuth sulphite glucose glycine yeast agar, were evaluated for the presumptive identification of yeast species. Methods A total number of 270 yeast strains including 169 Candida albicans, 33 C. tropicalis, 24 C. glabrata, 18 C. parapsilosis, 12 C. krusei, 5 Trichosporon spp., 4 C. kefyr, 2 C. lusitaniae, 1 Saccharomyces cerevisiae and 1 Geotrichum candidum were included. The strains were first identified by germ tube test, morphological characteristics on cornmeal tween 80 agar and Vitek 32 and API 20 C AUX systems. In parallel, they were also streaked onto CHROMagar Candida and bismuth sulphite glucose glycine yeast agar plates. The results were read according to the color, morphology of the colonies and the existance of halo around them after 48 hours of incubation at 37°C. Results The sensitivity and specificity values for C. albicans strains were found to be 99.4, 100% for CHROMagar Candida and 87.0, 75.2% for BiGGY agar, respectively. The sensitivity of CHROMagar Candida to identify C. tropicalis, C. glabrata and C. krusei ranged between 90.9 and 100% while the specificity was 100%. The sensitivity rates for BiGGY agar were 66.6 and 100% while the specificity values were found to be 95.4 and 100% for C. tropicalis and C. krusei, respectively. Conclusions It can be concluded that the use of CHROMagar Candida is an easy and reliable method for the presumptive identification of most commonly isolated Candida species especially C. albicans, C. tropicalis and C. krusei. The lower sensitivity and specificity of BiGGY agar to identify commonly isolated Candida species potentially limits the clinical usefulness of this agar. PMID:14613587

  20. Performance comparison of streak camera recording systems

    SciTech Connect

    Derzon, M.; Barber, T.

    1995-07-01

    Streak camera based diagnostics are vital to the inertial confinement fusion program at Sandia National Laboratories. Performance characteristics of various readout systems coupled to an EGG-AVO streak camera were analyzed and compared to scaling estimates. The purpose of the work was to determine the limits of the streak camera performance and the optimal fielding conditions for the Amador Valley Operations (AVO) streak camera systems. The authors measured streak camera limitations in spatial resolution and sensitivity. Streak camera limits on spatial resolution are greater than 18 lp/mm at 4% contrast. However, it will be difficult to make use of any resolution greater than this because of high spatial frequency variation in the photocathode sensitivity. They have measured a signal to noise of 3,000 with 0.3 mW/cm{sup 2} of 830 nm light at a 10 ns/mm sweep speed. They have compared lens coupling systems with and without micro-channel plate intensifiers and systems using film or charge coupled device (CCD) readout. There were no conditions where film was found to be an improvement over the CCD readout. Systems utilizing a CCD readout without an intensifier have comparable resolution, for these source sizes and at a nominal cost in signal to noise of 3, over those with an intensifier. Estimates of the signal-to-noise for different light coupling methods show how performance can be improved.

  1. Agar polysaccharides from Gracilaria species (Rhodophyta, Gracilariaceae).

    PubMed

    Marinho-Soriano, E

    2001-07-26

    Yield, physical and chemical properties of agar from three agarophytes species (Gracilaria gracilis, G. dura and G. bursa-pastoris) were determined. The agar yield from the three species varied significantly (P<0.01). The highest yields of agar (34.8%) and the lowest (30%) were obtained from G. bursa-pastoris and G. gracilis, respectively. Highest gel strength (630+/-15 g cm(-2)) was obtained from agar extracted from G. gracilis and lowest from G. bursa-pastoris (26+/-3.6 g cm(-2)). The values of 3,6-anhydrogalactose were similar for G. gracilis and G. dura and there were no significant differences among the species. The sulfate contents varied significantly (P<0.01) and the higher value was obtained from G. bursa-pastoris. Among the three species, G. gracilis showed superior agar quality than the other two species, hence it can be considered a good potential source for industrial use. PMID:11472802

  2. Update on the Rochester Optical Streak System

    NASA Astrophysics Data System (ADS)

    Jaanimagi, P. A.

    2005-10-01

    The Rochester Optical Streak System (ROSS) is a modern, self-calibrating, remotely controlled streak camera platform capable of accepting a variety of different streak tubes. The optical calibration module (OCM) for the ROSS camera has been completed and integrated with the main streak tube housing. The OCM incorporates an achromatic Offner triplet that allows fiber-delivered input and free-space propagated signals to be simultaneously relayed to the photocathode. It also encloses of the light sources and reticles required to accomplish a full suite of system calibrations including: autofocus of the input and electron optics, geometric distortion and flat-field correction, time base, system gain, and linearity. We will present data illustrating the system capabilities and our latest results comparing the dynamic performance of the P510 and P820 streak tubes. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-92SF19460.

  3. Hot streak characterization in serpentine exhaust nozzles

    NASA Astrophysics Data System (ADS)

    Crowe, Darrell S.

    Modern aircraft of the United States Air Force face increasingly demanding cost, weight, and survivability requirements. Serpentine exhaust nozzles within an embedded engine allow a weapon system to fulfill mission survivability requirements by providing denial of direct line-of-sight into the high-temperature components of the engine. Recently, aircraft have experienced material degradation and failure along the aft deck due to extreme thermal loading. Failure has occurred in specific regions along the aft deck where concentrations of hot gas have come in contact with the surface causing hot streaks. The prevention of these failures will be aided by the accurate prediction of hot streaks. Additionally, hot streak prediction will improve future designs by identifying areas of the nozzle and aft deck surfaces that require thermal management. To this end, the goal of this research is to observe and characterize the underlying flow physics of hot streak phenomena. The goal is accomplished by applying computational fluid dynamics to determine how hot streak phenomena is affected by changes in nozzle geometry. The present research first validates the computational methods using serpentine inlet experimental and computational studies. A design methodology is then established for creating six serpentine exhaust nozzles investigated in this research. A grid independent solution is obtained on a nozzle using several figures of merit and the grid-convergence index method. An investigation into the application of a second-order closure turbulence model is accomplished. Simulations are performed for all serpentine nozzles at two flow conditions. The research introduces a set of characterization and performance parameters based on the temperature distribution and flow conditions at the nozzle throat and exit. Examination of the temperature distribution on the upper and lower nozzle surfaces reveals critical information concerning changes in hot streak phenomena due to changes

  4. Dilution Confusion: Conventions for Defining a Dilution

    ERIC Educational Resources Information Center

    Fishel, Laurence A.

    2010-01-01

    Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

  5. Frost streaks in the south polar cap of Mars

    NASA Technical Reports Server (NTRS)

    Thomas, P.; Veverka, J.; Campos-Marquetti, R.

    1979-01-01

    Viking Orbiter images of the annual south polar cap on Mars exhibit elongated bright features that are associated with craters and resemble wind streaks observed elsewhere on Mars. The study focuses on the well-documented frost streaks. The discussion covers the morphology of frost streaks, occurrence, seasonal behavior, thickness of frost in streak deposits, wind patterns inferred from frost streaks and other eolian features in the south polar region, formation of frost streaks, and other locales of preferential frost accumulation. The form and seasonal behavior of the bright elongated albedo markings which extend from the rims of many craters in the south polar cap suggest that they are accumulations of CO2 frost in the lee of craters. The frost streaks appear in the fall, increasing in length but not changing in direction during fall and winter. The frost streaks indicate a prograde circulation pattern of near-surface winds around the pole. Other details are also presented.

  6. ASTRiDE: Automated Streak Detection for Astronomical Images

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Won

    2016-05-01

    ASTRiDE detects streaks in astronomical images using a "border" of each object (i.e. "boundary-tracing" or "contour-tracing") and their morphological parameters. Fast moving objects such as meteors, satellites, near-Earth objects (NEOs), or even cosmic rays can leave streak-like traces in the images; ASTRiDE can detect not only long streaks but also relatively short or curved streaks.

  7. Some Experiments With Agar-Grown Seedlings

    ERIC Educational Resources Information Center

    Freeland, P. W.

    1973-01-01

    Two percent agar gel is reported as a better medium for germination and growth studies. Students can be encouraged to undertake many simple experiments and make precise observations by using this medium. (PS)

  8. The first satellite laser echoes recorded on the streak camera

    NASA Technical Reports Server (NTRS)

    Hamal, Karel; Prochazka, Ivan; Kirchner, Georg; Koidl, F.

    1993-01-01

    The application of the streak camera with the circular sweep for the satellite laser ranging is described. The Modular Streak Camera system employing the circular sweep option was integrated into the conventional Satellite Laser System. The experimental satellite tracking and ranging has been performed. The first satellite laser echo streak camera records are presented.

  9. Perception of Randomness: On the Time of Streaks

    ERIC Educational Resources Information Center

    Sun, Yanlong; Wang, Hongbin

    2010-01-01

    People tend to think that streaks in random sequential events are rare and remarkable. When they actually encounter streaks, they tend to consider the underlying process as non-random. The present paper examines the time of pattern occurrences in sequences of Bernoulli trials, and shows that among all patterns of the same length, a streak is the…

  10. Dark Streaks Over-riding Inactive Dunes

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Not all sand dunes on Mars are active in the modern martian environment. This example from the Lycus Sulci (Olympus Mons'aureole') region shows a case where small windblown dunes at the base of a slope have been over-ridden by more recent dark streaks (arrows). The dark streaks are most likely caused by what geologists call mass wasting or mass movement (landslides and avalanches are mass movements). Dark slope streaks such as these are common in dustier regions of Mars, and they appear to result from movement of extremely dry dust or sand in an almost fluidlike manner down a slope. This movement disrupts the bright dust coating on the surface and thus appears darker than the surrounding terrain.

    In this case, the dark slope streaks have moved up and over the dunes at the bottom of the slope, indicating that the process that moves sediment down the slope is more active (that is, it has occurred more recently and hence is more likely to occur) in the modern environment than is the movement of dunes and ripples at this location on Mars. The dunes, in fact, are probably mantled by dust. This October 1997 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture is illuminated from the left and located near 31.6oN, 134.0oW.

  11. Bichromatic particle streak velocimetry bPSV

    NASA Astrophysics Data System (ADS)

    Voss, Björn; Stapf, Julian; Berthe, André; Garbe, Christoph S.

    2012-11-01

    We propose a novel technique for three-dimensional three-component (3D3C) interfacial flow measurement. It is based on the particle streak velocimetry principle. A relatively long integration time of the camera is used for capturing the movement of tracer particles as streaks on the sensor. The velocity along these streaks is extracted by periodically changing the illumination using a known pattern. A dye with different absorption characteristics in two distinct wavelengths is used to color the fluid. The depth of particles relative to the fluid interface can then be computed from their intensities when illuminated with light sources at those two different wavelengths. Hence, from our approach, a bichromatic, periodical illumination together with an image processing routine for precisely extracting particle streak features is used for measuring 3D3C fluid flow with a single camera. The technique is applied to measuring turbulent Rayleigh-Bénard convection at the free air--water interface. Using Lagrangian statistics, we are able to demonstrate a clear transition from the Batchelor regime to the Richardson regime, both of which were postulated for isotropic turbulence. The relative error of the velocity extraction of our new technique was found to be below 0.5 %.

  12. Lecithin-agar assay for lecithinase antibodies in serum.

    PubMed

    Sibinovic, K H; Brown, F A; Pettigrew, K D; Vought, R L

    1971-01-01

    A technique for assay of lecithinase antibodies in serum was developed in this laboratory by using a lecithin-agar plate diffusion procedure based on a combination of described plate assays. Egg yolk lipoprotein composed primarily of lecithin was used as a substrate for reaction with free or non-neutralized lecithinase C after incubation of known amounts of lecithinase C with various dilutions of control and test sera. It was found that the size of the reaction zone was a function of enzyme concentration and inversely proportional to the antibody concentration. Accuracy and precision of the assay were determined. In addition, lecithinase antibody levels in sera from experimentally inoculated rats and rabbits and sera from randomly selected human patients were studied. PMID:4322282

  13. Lecithin-Agar Assay for Lecithinase Antibodies in Serum

    PubMed Central

    Sibinovic, Kyle H.; Brown, Freddie A.; Pettigrew, Karen D.; Vought, Robert L.

    1971-01-01

    A technique for assay of lecithinase antibodies in serum was developed in this laboratory by using a lecithin-agar plate diffusion procedure based on a combination of described plate assays. Egg yolk lipoprotein composed primarily of lecithin was used as a substrate for reaction with free or non-neutralized lecithinase C after incubation of known amounts of lecithinase C with various dilutions of control and test sera. It was found that the size of the reaction zone was a function of enzyme concentration and inversely proportional to the antibody concentration. Accuracy and precision of the assay were determined. In addition, lecithinase antibody levels in sera from experimentally inoculated rats and rabbits and sera from randomly selected human patients were studied. Images PMID:4322282

  14. Wind Streaks on Venus: Clues to Atmospheric Circulation

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Schubert, Gerald; Limonadi, Daniel; Bender, Kelly C.; Newman, William I.; Thomas, Peggy E.; Weitz, Catherine M.; Wall, Stephen D.

    1994-01-01

    Magellan images reveal surface features on Venus attributed to wind processes. Sand dunes, wind-sculpted hills, and more than 5830 wind streaks have been identified. The streaks serve as local "wind vanes," representing wind direction at the time of streak formation and allowing the first global mapping of near-surface wind patterns on Venus. Wind streaks are oriented both toward the equator and toward the west. When streaks associated with local transient events, such as impact cratering, are deleted, the westward component is mostly lost but the equatorward component remains. This pattern is consistent with a Hadley circulation of the lower atmosphere.

  15. An Agar-Based Method for Plating Marine Protozoan Parasites of the Genus Perkinsus

    PubMed Central

    Cold, Emma R.; Freyria, Nastasia J.; Martínez Martínez, Joaquín; Fernández Robledo, José A.

    2016-01-01

    The genus Perkinsus includes protozoan parasites of mollusks responsible for losses in the aquaculture industry and hampering the recovery of natural shellfish beds worldwide, and they are a key taxon for understanding intracellular parasitism adaptations. The ability to propagate the parasite in liquid media, in the absence of the host, has been crucial for improving understanding of its biology; however, alternative techniques to grow the parasite are needed to explore other basic aspects of the Perkinsus spp. biology. We optimized a DME: Ham’s F12–5% FBS- containing solid agar medium for plating Perkinsus marinus. This solid medium supported trophozoite propagation both by binary fission and schizogony. Colonies were visible to the naked eye 17 days after plating. We tested the suitability of this method for several applications, including the following: 1) Subcloning P. marinus isolates: single discrete P. marinus colonies were obtained from DME: Ham’s F12–5% FBS– 0.75% agar plates, which could be further propagated in liquid medium; 2) Subcloning engineered Perkinsus mediterraneus MOE[MOE]: GFP by streaking cultures on plates; 3) Chemical susceptibility: Infusing the DME: Ham’s F12–5% FBS– 0.75% agar plates with triclosan resulted in inhibition of the parasite propagation in a dose-dependent manner. Altogether, our plating method has the potential for becoming a key tool for investigating diverse aspects of Perkinsus spp. biology, developing new molecular tools, and for biotechnological applications. PMID:27149378

  16. An Agar-Based Method for Plating Marine Protozoan Parasites of the Genus Perkinsus.

    PubMed

    Cold, Emma R; Freyria, Nastasia J; Martínez Martínez, Joaquín; Fernández Robledo, José A

    2016-01-01

    The genus Perkinsus includes protozoan parasites of mollusks responsible for losses in the aquaculture industry and hampering the recovery of natural shellfish beds worldwide, and they are a key taxon for understanding intracellular parasitism adaptations. The ability to propagate the parasite in liquid media, in the absence of the host, has been crucial for improving understanding of its biology; however, alternative techniques to grow the parasite are needed to explore other basic aspects of the Perkinsus spp. biology. We optimized a DME: Ham's F12-5% FBS- containing solid agar medium for plating Perkinsus marinus. This solid medium supported trophozoite propagation both by binary fission and schizogony. Colonies were visible to the naked eye 17 days after plating. We tested the suitability of this method for several applications, including the following: 1) Subcloning P. marinus isolates: single discrete P. marinus colonies were obtained from DME: Ham's F12-5% FBS- 0.75% agar plates, which could be further propagated in liquid medium; 2) Subcloning engineered Perkinsus mediterraneus MOE[MOE]: GFP by streaking cultures on plates; 3) Chemical susceptibility: Infusing the DME: Ham's F12-5% FBS- 0.75% agar plates with triclosan resulted in inhibition of the parasite propagation in a dose-dependent manner. Altogether, our plating method has the potential for becoming a key tool for investigating diverse aspects of Perkinsus spp. biology, developing new molecular tools, and for biotechnological applications. PMID:27149378

  17. Photonic streaking of attosecond pulse trains

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Taec; Zhang, Chunmei; Ruchon, Thierry; Hergott, Jean-François; Auguste, Thierry; Villeneuve, D. M.; Corkum, P. B.; Quéré, F.

    2013-08-01

    High harmonic radiation, produced when intense laser pulses interact with matter, is composed of a train of attosecond pulses. Individual pulses in this train carry information on ultrafast dynamics that vary from one half-optical-cycle to the next. Here, we demonstrate an all-optical photonic streaking measurement that provides direct experimental access to each attosecond pulse by mapping emission time onto propagation angle. This is achieved by inducing an ultrafast rotation of the instantaneous laser wavefront at the focus. We thus time-resolve attosecond pulse train generation, and hence the dynamics in the nonlinear medium itself. We apply photonic streaking to harmonic generation in gases and directly observe, for the first time, the influence of non-adiabatic electron dynamics and plasma formation on the generated attosecond pulse train. These experimental and numerical results also provide the first evidence of the generation of attosecond lighthouses in gases, which constitute ideal sources for attosecond pump-probe spectroscopy.

  18. Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation.

    PubMed

    Velimirovic, Milica; Schmid, Doris; Wagner, Stephan; Micić, Vesna; von der Kammer, Frank; Hofmann, Thilo

    2016-09-01

    Submicron-scale milled zerovalent iron (milled ZVI) particles produced by grinding macroscopic raw materials could provide a cost-effective alternative to nanoscale zerovalent iron (nZVI) particles for in situ degradation of chlorinated aliphatic hydrocarbons in groundwater. However, the aggregation and settling of bare milled ZVI particles from suspension presents a significant obstacle to their in situ application for groundwater remediation. In our investigations we reduced the rapid aggregation and settling rate of bare milled ZVI particles from suspension by stabilization with a "green" agar agar polymer. The transport potential of stabilized milled ZVI particle suspensions in a diverse array of natural heterogeneous porous media was evaluated in a series of well-controlled laboratory column experiments. The impact of agar agar on trichloroethene (TCE) removal by milled ZVI particles was assessed in laboratory-scale batch reactors. The use of agar agar significantly enhanced the transport of milled ZVI particles in all of the investigated porous media. Reactivity tests showed that the agar agar-stabilized milled ZVI particles were reactive towards TCE, but that their reactivity was an order of magnitude less than that of bare, non-stabilized milled ZVI particles. Our results suggest that milled ZVI particles could be used as an alternative to nZVI particles as their potential for emplacement into contaminated zone, their reactivity, and expected longevity are beneficial for in situ groundwater remediation. PMID:26596889

  19. Pigments of fly agaric (Amanita muscaria).

    PubMed

    Stintzing, Florian; Schliemann, Willibald

    2007-01-01

    The complex pigment pattern of fly agaric (Amanita muscaria) cap skins has been studied by LC-DAD and mass spectrometry. Among the betaxanthins the corresponding derivatives of serine, threonine, ethanolamine, alanine, Dopa, phenylalanine and tryptophan are reported for the first time to contribute to the pigment pattern of fly agarics. Betalamic acid, the chromophoric precursor of betaxanthins and betacyanins, muscaflavin and seco-dopas were also detected. Furthermore, the red-purple muscapurpurin and the red muscarubrin were tentatively assigned while further six betacyanin-like components could not be structurally allocated. Stability studies indicated a high susceptibility of pigment extracts to degradation which led to rapid colour loss thus rendering a complete characterization of betacyanin-like compounds impossible at present. Taking into account these difficulties the presented results may be a starting point for a comprehensive characterization of the pigment composition of fly agarics. PMID:18274277

  20. Understanding baseball team standings and streaks

    NASA Astrophysics Data System (ADS)

    Sire, C.; Redner, S.

    2009-02-01

    Can one understand the statistics of wins and losses of baseball teams? Are their consecutive-game winning and losing streaks self-reinforcing or can they be described statistically? We apply the Bradley-Terry model, which incorporates the heterogeneity of team strengths in a minimalist way, to answer these questions. Excellent agreement is found between the predictions of the Bradley-Terry model and the rank dependence of the average number team wins and losses in major-league baseball over the past century when the distribution of team strengths is taken to be uniformly distributed over a finite range. Using this uniform strength distribution, we also find very good agreement between model predictions and the observed distribution of consecutive-game team winning and losing streaks over the last half-century; however, the agreement is less good for the previous half-century. The behavior of the last half-century supports the hypothesis that long streaks are primarily statistical in origin with little self-reinforcing component. The data further show that the past half-century of baseball has been more competitive than the preceding half-century.

  1. Particle Streak Velocimetry of Supersonic Nozzle Flows

    NASA Technical Reports Server (NTRS)

    Willits, J. D.; Pourpoint, T. L.

    2016-01-01

    A novel velocimetry technique to probe the exhaust flow of a laboratory scale combustor is being developed. The technique combines the advantages of standard particle velocimetry techniques and the ultra-fast imaging capabilities of a streak camera to probe high speed flows near continuously with improved spatial and velocity resolution. This "Particle Streak Velocimetry" technique tracks laser illuminated seed particles at up to 236 picosecond temporal resolution allowing time-resolved measurement of one-dimensional flows exceeding 2000 m/s as are found in rocket nozzles and many other applications. Developmental tests with cold nitrogen have been performed to validate and troubleshoot the technique with supersonic flows of much lower velocity and without background noise due to combusting flow. Flow velocities on the order of 500 m/s have been probed with titanium dioxide particles and a continuous-wave laser diode. Single frame images containing multiple streaks are analyzed to find the average slope of all incident particles corresponding to the centerline axial flow velocity. Long term objectives for these tests are correlation of specific impulse to theoretical combustion predictions and direct comparisons between candidate green fuels and the industry standard, monomethylhydrazine, each tested under identical conditions.

  2. Standard operating procedure to prepare agar phantoms

    NASA Astrophysics Data System (ADS)

    Souza, R. M.; Santos, T. Q.; Oliveira, D. P.; Souza, R. M.; Alvarenga, A. V.; Costa-Felix, R. P. B.

    2016-07-01

    Agar phantoms are widely used as soft tissue mimics and some preparation techniques are described in the literature. There are also standards that describe the recipe of a soft tissue mimicking material (TMM). However some details of manufacture process are not clearly defined. The standardization of the phantom's preparation can produce a metrological impact on the results of the acoustic properties measured. In this direction, this paper presents a standard operating procedure (SOP) to prepare the agar TMM described on the IEC 60601-237.

  3. Use of agar agar stabilized milled zero-valent iron particles for in situ groundwater remediation

    NASA Astrophysics Data System (ADS)

    Schmid, Doris; Velimirović, Milica; Wagner, Stephan; Micić Batka, Vesna; von der Kammer, Frank; Hofmann, Thilo

    2015-04-01

    A major obstacle for use of nanoscale zero-valent iron (nZVI) particles as a nontoxic material for effective in situ degradation of chlorinated aliphatic hydrocarbons (CAHs) is the high production cost. For that reason, submicro-scale milled zero-valent iron particles were recently developed (milled ZVI, UVR-FIA, Germany) by grinding macroscopic raw materials of elementary iron as a cheaper alternative to products produced by solid-state reduction. However, milled ZVI particles tend to aggregate and due to the rather large particle size (d50= 11.9 µm) also rapidly sediment. To prevent aggregation and consequently sedimentation of milled ZVI particles and therefore improve the mobility after in situ application, the use of a stabilizer is considered in literature as a most promising option. In this study, milled ZVI particles (1 g L-1 of particle concentration) were stabilized by environmentally friendly polymer agar agar (>0.5 g L-1), which had a positive impact on the milled ZVI stability. Sedimentation rate was significantly decreased by increasing the suspension viscosity. Column transport experiments were performed for bare and agar agar stabilized milled ZVI particles in commercially available fine grained quartz sand (DORSILIT® Nr.8, Gebrüder Dorfner GmbH Co, Germany) and different porous media collected from brownfields. The experiments were carried out under field relevant injection conditions of 100 m d-1. The maximal travel distance (LT) of less than 10 cm was determined for non-stabilized suspension in fine grained quartz sand, while agar agar (1 g L-1) stabilized milled ZVI suspension revealed LT of 12 m. Similar results were observed for porous media from brownfields showing that mobility of agar agar stabilized particle suspensions was significantly improved compared to bare particles. Based on the mobility data, agar agar stabilized milled zero-valent iron particles could be used for in situ application. Finally, lab-scale batch degradation

  4. Signal averaging x-ray streak camera with picosecond jitter

    NASA Astrophysics Data System (ADS)

    Maksimchuk, A.; Kim, M.; Workman, J.; Korn, G.; Squier, J.; Du, D.; Umstadter, D.; Mourou, G.; Bouvier, M.

    1996-03-01

    We have developed an averaging picosecond x-ray streak camera using a dc-biased photoconductive switch as a generator of a high-voltage ramp. The streak camera is operated at a sweep speed of up to 8 ps/mm, shot-to-shot jitter is less than ±1 ps. The streak camera has been used to measure the time history of broadband x-ray emission from an ultrashort pulse laser-produced plasma. Accumulation of the streaked x-ray signals significantly improved the signal-to-noise ratio of the data obtained.

  5. Compressible laminar streaks with wall suction

    NASA Astrophysics Data System (ADS)

    Ricco, Pierre; Shah, Daniel; Hicks, Peter D.

    2013-05-01

    The response of a compressible laminar boundary layer subject to free-stream vortical disturbances and steady mean-flow wall suction is studied. The theoretical frameworks of Leib et al. [J. Fluid Mech. 380, 169-203 (1999), 10.1017/S0022112098003504] and Ricco and Wu [J. Fluid Mech. 587, 97-138 (2007), 10.1017/S0022112007007070], based on the linearized unsteady boundary-region equations, are adopted to study the influence of suction on the kinematic and thermal streaks arising through the interaction between the free-stream vortical perturbations and the boundary layer. In the asymptotic limit of small spanwise wavelength compared with the boundary layer thickness, i.e., when the disturbance flow is conveniently described by the steady compressible boundary region equations, the effect of suction is mild on the velocity fluctuations and negligible on the temperature fluctuations. When the spanwise wavelength is comparable with the boundary layer thickness, small suction values intensify the supersonic streaks, while higher transpiration levels always stabilize the disturbances at all Mach numbers. At larger spanwise wavelengths, very small amplitudes of wall transpiration have a dramatic stabilizing effect on all boundary layer fluctuations, which can take the form of transiently growing thermal streaks, large amplitude streamwise oscillations, or oblique exponentially growing Tollmien-Schlichting waves, depending on the Mach number and the wavelengths. The range of wavenumbers for which the exponential growth occurs becomes narrower and the location of instability is significantly shifted downstream by mild suction, indicating that wall transpiration can be a suitable vehicle for delaying transition when the laminar breakdown is promoted by these unstable disturbances. The typical streamwise wavelength of these disturbances is instead not influenced by suction, and asymptotic triple deck theory predicts the strong changes in growth rate and the very mild

  6. X-ray streak crystal spectography

    SciTech Connect

    Kauffman, R.L.; Brown, T.; Medecki, H.

    1983-07-01

    We have built an x-ray streaked crystal spectrograph for making time-resolved x-ray spectral measurements. This instrument can access Bragg angles from 11/sup 0/ to 38/sup 0/ and x-ray spectra from 200 eV to greater than 10 keV. We have demonstrated resolving powers, E/..delta..E > 200 at 1 keV and time resolution less than 20 psec. A description of the instrument and an example of the data is given.

  7. Mass movement slope streaks imaged by the Mars Orbiter Camera

    NASA Astrophysics Data System (ADS)

    Sullivan, Robert; Thomas, Peter; Veverka, Joseph; Malin, Michael; Edgett, Kenneth S.

    2001-10-01

    Narrow, fan-shaped dark streaks on steep Martian slopes were originally observed in Viking Orbiter images, but a definitive explanation was not possible because of resolution limitations. Pictures acquired by the Mars Orbiter Camera (MOC) aboard the Mars Global Surveyor (MGS) spacecraft show innumerable examples of dark slope streaks distributed widely, but not uniformly, across the brighter equatorial regions, as well as individual details of these features that were not visible in Viking Orbiter data. Dark slope streaks (as well as much rarer bright slope streaks) represent one of the most widespread and easily recognized styles of mass movement currently affecting the Martian surface. New dark streaks have formed since Viking and even during the MGS mission, confirming earlier suppositions that higher contrast dark streaks are younger, and fade (brighten) with time. The darkest slope streaks represent ~10% contrast with surrounding slope materials. No small outcrops supplying dark material (or bright material, for bright streaks) have been found at streak apexes. Digitate downslope ends indicate slope streak formation involves a ground-hugging flow subject to deflection by minor topographic obstacles. The model we favor explains most dark slope streaks as scars from dust avalanches following oversteepening of air fall deposits. This process is analogous to terrestrial avalanches of oversteepened dry, loose snow which produce shallow avalanche scars with similar morphologies. Low angles of internal friction typically 10-30¡ for terrestrial loess and clay materials suggest that mass movement of (low-cohesion) Martian dusty air fall is possible on a wide range of gradients. Martian gravity, presumed low density of the air fall deposits, and thin (unresolved by MOC) failed layer depths imply extremely low cohesive strength at time of failure, consistent with expectations for an air fall deposit of dust particles. As speed increases during a dust avalanche, a

  8. Luminescent DNA- and agar-based membranes.

    PubMed

    Leones, R; Fernandes, M; Ferreira, R A S; Cesarino, I; Lima, J F; Carlos, L D; Bermudez, V de Zea; Magon, C J; Donoso, J P; Silva, M M; Pawlicka, A

    2014-09-01

    Luminescent materials containing europium ions are investigated for different optical applications. They can be obtained using bio-macromolecules, which are promising alternatives to synthetic polymers based on the decreasing oil resources. This paper describes studies of the DNA- and Agar-europium triflate luminescent membranes and its potential technological applications are expanded to electroluminescent devices. Polarized optical microscopy demonstrated that the samples are birefringent with submicrometer anisotropy. The X-ray diffraction analysis revealed predominantly amorphous nature of the samples and the atomic force microscopy images showed a roughness of the membranes of 409.0 and 136.1 nm for the samples of DNA10Eu and Agar1.11Eu, respectively. The electron paramagnetic resonance spectra of the DNA(n)Eu membranes with the principal lines at g ≈ 2.0 and g ≈ 4.8 confirmed uniform distribution of rare earth ions in a disordered matrix. Moreover, these strong and narrow resonance lines for the samples of DNA(n)Eu when compared to the Agar(n)Eu suggested a presence of paramagnetic radicals arising from the DNA matrix. The emission spectra suggested that the Eu3+ ions occupy a single local environment in both matrices and the excitation spectra monitored around the Eu emission lines pointed out that the Eu3+ ions in the Agar host were mainly excited via the broad band component rather than by direct intra-4f(6) excitation, whereas the opposite case occurred for the DNA-based sample. PMID:25924317

  9. Development of a novel cross-streaking method for isolation, confirmation, and enumeration of Salmonella from irrigation ponds.

    PubMed

    Luo, Zhiyao; Gu, Ganyu; Giurcanu, Mihai C; Adams, Paige; Vellidis, George; van Bruggen, Ariena H C; Wright, Anita C

    2014-06-01

    The 2013 Produce Safety Rules in Food Safety Modernization Act (FSMA) require regular testing for generic Escherichia coli in agricultural water intended for pre-harvest contact with the edible portion of fresh produce. However, the use of fecal contamination indicators frequently does not correctly reflect distribution of foodborne pathogens such as Salmonella enterica, and ensuring food safety may require direct detection and enumeration of pathogens in agricultural settings. Herein we report the evaluation of different cost-effective methods for quantification, isolation, and confirmation of Salmonella in irrigation pond water and sediment samples. A most probably number (MPN) dual enrichment culture method was used in combination with differential and selective agars, XLT4 and CHROMagar™ Salmonella plus (CSP). The necessity for PCR confirmation was evaluated, and methods were compared by cost and performance measures (i.e., sensitivity, specificity, positive predictive value, and negative predictive value). Statistical analyses showed that using XLT4 as the initial selective agar to isolate Salmonella colonies improved recovery compared to CSP agar; however, PCR confirmation was required to avoid false positive results on either agar. Therefore, a novel cross-streaking method utilizing CHROMagar™ agar for individual colony confirmation of Salmonella presence/absence on XLT4 was developed. This method classifies the colony as positive if typical Salmonella appearance is observed on both agars. Statistical analysis showed that this method was as effective as PCR for species confirmation of pure individual strains isolated from enrichment cultures (sensitivity=0.99, specificity=1.00, relative to PCR). This method offers a cost-effective alternative to PCR that would increase the capacity and sensitivity of Salmonella evaluation. PMID:24732066

  10. SDOSS: A spatially discriminating, optical streaked spectrograph

    SciTech Connect

    Cobble, J.; Evans, S.; Fernandez, J.; Oertel, J.; Watt, R.; Wilde, B.

    1995-05-01

    SDOSS is employed to study broadband laser scattering encompassing SBS, SRS, and the 3/2-{omega} signature of two plasmon decay for ns-scale laser-plasma experiments with 351 or 527-nm drive. It uses a Cassegrain telescope to image scattered light from a laser plasma onto a field stop. The telescope magnification and the stop aperture provide spatial discrimination of target plane scatter. A UV lens relays the image to a 0.25-m spectrograph which is lens coupled to a streak camera with an S-1 photocathode. The streak output is imaged onto a CCD camera. In its 512 x 480 pixel array, the CCD covers a spectral range from 200 to 800 nm with 4-nm resolution and can be adjusted to look from 350 to 1,060 nm. The sweep speed is variable with full window values of 30, 12, 6 ns, and faster. An optical fiducial provides a spectral and temporal marker. On the Livermore Nova laser, SDOSS has been used to determine spatial density in gas-filled hohlraums from SRS signals. At Trident in Los Alamos, it has been employed for similar measurements with long scale length plasmas in SBS and SRS seeding experiments. It has proven to be a versatile tool for studying the physics of laser-generated plasmas.

  11. Estimation method for serial dilution experiments.

    PubMed

    Ben-David, Avishai; Davidson, Charles E

    2014-12-01

    Titration of microorganisms in infectious or environmental samples is a corner stone of quantitative microbiology. A simple method is presented to estimate the microbial counts obtained with the serial dilution technique for microorganisms that can grow on bacteriological media and develop into a colony. The number (concentration) of viable microbial organisms is estimated from a single dilution plate (assay) without a need for replicate plates. Our method selects the best agar plate with which to estimate the microbial counts, and takes into account the colony size and plate area that both contribute to the likelihood of miscounting the number of colonies on a plate. The estimate of the optimal count given by our method can be used to narrow the search for the best (optimal) dilution plate and saves time. The required inputs are the plate size, the microbial colony size, and the serial dilution factors. The proposed approach shows relative accuracy well within ±0.1log10 from data produced by computer simulations. The method maintains this accuracy even in the presence of dilution errors of up to 10% (for both the aliquot and diluent volumes), microbial counts between 10(4) and 10(12) colony-forming units, dilution ratios from 2 to 100, and plate size to colony size ratios between 6.25 to 200. PMID:25205541

  12. Radar-visible wind streaks in the Altiplano of Bolivia

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Christensen, P.

    1984-01-01

    Isolated knobs that are erosional remnants of central volcanoes or of folded rocks occur in several areas of the Altiplano are visible on both optical and images. The optically visible streaks occur in the immediate lee of the knobs, whereas the radar visible streaks occur in the zone downwind between the knobs. Aerial reconnaissance and field studies showed that the optically visible streaks consist of a series of small ( 100 m wide) barchan and barchanoid dunes, intradune sand sheets, and sand hummocks (large shrub coppice dunes) up to 15 m across and 5 m high. On LANDSAT images these features are poorly resolved but combine to form a bright streak. On the radar image, this area also appears brighter than the zone of the radar dark streak; evidently, the dunes and hummocks serve as radar reflectors. The radar dark streak consists of a relatively flat, smooth sand sheet which lacks organized aerolian bedforms, other than occasional ripples. Wind velocity profiles show a greater U value in the optically bright streak zone than in the radar dark streak.

  13. Thermodynamics of Dilute Solutions.

    ERIC Educational Resources Information Center

    Jancso, Gabor; Fenby, David V.

    1983-01-01

    Discusses principles and definitions related to the thermodynamics of dilute solutions. Topics considered include dilute solution, Gibbs-Duhem equation, reference systems (pure gases and gaseous mixtures, liquid mixtures, dilute solutions), real dilute solutions (focusing on solute and solvent), terminology, standard states, and reference systems.…

  14. Syneresis and delayed detachment in agar plates.

    PubMed

    Divoux, Thibaut; Mao, Bosi; Snabre, Patrick

    2015-05-14

    Biogels made of crosslinked polymers such as proteins or polysaccharides behave as porous soft solids and store large amounts of solvent. These gels undergo spontaneous aging, called syneresis, which consists of the shrinkage of the gel matrix and the progressive expulsion of solvent. As a result, a biogel originally casted in a container often loses contact with the container sidewalls, and the detachment time is difficult to anticipate a priori, since it may occur over variable time spans (from hours to days). Here we report on syneresis phenomena in agar plates, which consist of Petri dishes filled with a gel mainly composed of agar. Direct observations and speckle pattern correlation analysis allow us to rationalize the delayed detachment of the gel from the sidewall of the Petri dish. The detachment time t* is surprisingly not controlled by the mass loss as one would intuitively expect. Instead, t* is strongly correlated to the gel minimum thickness emin measured along the sidewall of the plate, and increases as a robust function of emin, independently of the prior mass-loss history. Time-resolved correlation spectroscopy atypically applied to such weakly diffusive media gives access to the local thinning rate of the gel. This technique also allows us to detect the gel micro-displacements that are triggered by water evaporation prior to the detachment, and even to anticipate the latter from a few hours. Our work provides observables to predict the detachment time of agar gels in dishes, and highlights the relevance of speckle pattern correlation analysis for the quantitative investigation of the syneresis dynamics in biopolymer gels. PMID:25812667

  15. Inducible Resistance to Maize Streak Virus

    PubMed Central

    Shepherd, Dionne N.; Dugdale, Benjamin; Martin, Darren P.; Varsani, Arvind; Lakay, Francisco M.; Bezuidenhout, Marion E.; Monjane, Adérito L.; Thomson, Jennifer A.; Dale, James; Rybicki, Edward P.

    2014-01-01

    Maize streak virus (MSV), which causes maize streak disease (MSD), is the major viral pathogenic constraint on maize production in Africa. Type member of the Mastrevirus genus in the family Geminiviridae, MSV has a 2.7 kb, single-stranded circular DNA genome encoding a coat protein, movement protein, and the two replication-associated proteins Rep and RepA. While we have previously developed MSV-resistant transgenic maize lines constitutively expressing “dominant negative mutant” versions of the MSV Rep, the only transgenes we could use were those that caused no developmental defects during the regeneration of plants in tissue culture. A better transgene expression system would be an inducible one, where resistance-conferring transgenes are expressed only in MSV-infected cells. However, most known inducible transgene expression systems are hampered by background or “leaky” expression in the absence of the inducer. Here we describe an adaptation of the recently developed INPACT system to express MSV-derived resistance genes in cell culture. Split gene cassette constructs (SGCs) were developed containing three different transgenes in combination with three different promoter sequences. In each SGC, the transgene was split such that it would be translatable only in the presence of an infecting MSV’s replication associated protein. We used a quantitative real-time PCR assay to show that one of these SGCs (pSPLITrepIII-Rb-Ubi) inducibly inhibits MSV replication as efficiently as does a constitutively expressed transgene that has previously proven effective in protecting transgenic maize from MSV. In addition, in our cell-culture based assay pSPLITrepIII-Rb-Ubi inhibited replication of diverse MSV strains, and even, albeit to a lesser extent, of a different mastrevirus species. The application of this new technology to MSV resistance in maize could allow a better, more acceptable product. PMID:25166274

  16. Characteristic features and dye degrading capability of agar-agar gel immobilized manganese peroxidase.

    PubMed

    Bilal, Muhammad; Asgher, Muhammad; Shahid, Muhammad; Bhatti, Haq Nawaz

    2016-05-01

    Immobilization of enzymes has been regarded as an efficient approach to develop biocatalyst with improved activity and stability characteristics under reaction conditions. In the present study, purified manganese peroxidase (MnP) from Ganoderma lucidum IBL-05 was immobilized in agar-agar support using entrapment technique. Maximum immobilization yield was accomplished at 4.0% agar-agar gel. The immobilized MnP exhibited better resistance to changes in pH and temperature than the free enzyme, with optimal conditions being pH 6.0 and 50 °C. The kinetic parameters Km and Kcat/Km for free and entrapped MnP were calculated to be 65.6 mM and 6.99 M(-1) s(-1), and 82 mM and 8.15 M(-1) s(-1), respectively. Thermo-stability was significantly improved after immobilization. After 120 h, the insolubilized MnP retained its activity up to 71.9% and 60.3% at 30 °C and 40 °C, respectively. It showed activity until 10th cycle and retained 74.3% residual activity after 3th cycle. The effects of H2O2, ionic strength and potential inhibitors on activity of free and immobilized enzyme were investigated. Moreover, the decolorization of three structurally different dyes was monitored in order to assess the degrading capability of the entrapped MnP. The decolorization efficiencies for all the tested dyes were 78.6-84.7% after 12h. The studies concluded that the toxicity of dyes aqueous solutions was significantly reduced after treatment. The remarkable catalytic, thermo-stability and re-cycling features of the agar-agar immobilized MnP display a high potential for biotechnological applications. PMID:26854887

  17. Comparative analysis of Panicum streak virus and Maize streak virus diversity, recombination patterns and phylogeography

    PubMed Central

    2009-01-01

    Background Panicum streak virus (PanSV; Family Geminiviridae; Genus Mastrevirus) is a close relative of Maize streak virus (MSV), the most serious viral threat to maize production in Africa. PanSV and MSV have the same leafhopper vector species, largely overlapping natural host ranges and similar geographical distributions across Africa and its associated Indian Ocean Islands. Unlike MSV, however, PanSV has no known economic relevance. Results Here we report on 16 new PanSV full genome sequences sampled throughout Africa and use these together with others in public databases to reveal that PanSV and MSV populations in general share very similar patterns of genetic exchange and geographically structured diversity. A potentially important difference between the species, however, is that the movement of MSV strains throughout Africa is apparently less constrained than that of PanSV strains. Interestingly the MSV-A strain which causes maize streak disease is apparently the most mobile of all the PanSV and MSV strains investigated. Conclusion We therefore hypothesize that the generally increased mobility of MSV relative to other closely related species such as PanSV, may have been an important evolutionary step in the eventual emergence of MSV-A as a serious agricultural pathogen. The GenBank accession numbers for the sequences reported in this paper are GQ415386-GQ415401 PMID:19903330

  18. Streak interactions and breakdown in boundary layer flows

    NASA Astrophysics Data System (ADS)

    Brandt, Luca; de Lange, H. C.

    2008-02-01

    The objective of this paper is to show that the interaction of streamwise velocity streaks of finite length can lead to turbulent breakdown in the flat-plate boundary layer flow. The work is motivated by previous numerical and experimental studies of transitional flows where the high-frequency oscillations leading to turbulence are seen to form in the region of strongest shear induced by streaks in relative motion. Therefore, a model for the interaction of steady and unsteady (i.e., slowly moving in the spanwise direction) spanwise periodic streaks is proposed. The interaction of two subsequent streaks is investigated for varying collision parameters. In particular, the relative spanwise position and angle are considered. The results show that the interaction is able to produce both a symmetric and asymmetric breakdown without the need for additional random noise from the main stream. Velocity structures characteristic of both scenarios are analyzed. Hairpin and Λ vortices are found in the case of symmetric collision between a low-speed region and an incoming high-speed streak, when a region of strong wall-normal shear is induced. Alternatively, when the incoming high-momentum fluid is misaligned with the low-speed streak in front, single quasi-streamwise vortices are identified. Despite the different symmetry at the breakdown, the detrimental interaction involves for both cases the tail of a low-speed region and the head of a high-speed streak. Further, the breakdown appears in both scenarios as an instability of three-dimensional shear layers formed between the two streaks. The streak interaction scenario is suggested to be of relevance for turbulence production in wall-bounded flows.

  19. Antimicrobial susceptibility testing of Australian isolates of Brachyspira hyodysenteriae using a new broth dilution method.

    PubMed

    Karlsson, Märit; Oxberry, Sophy L; Hampson, David J

    2002-01-01

    The antimicrobial susceptibilities of 76 field isolates of Brachyspira hyodysenteriae from different states of Australia were tested in a newly developed broth dilution procedure. The antimicrobial agents used were tiamulin, valnemulin, tylosin, erythromycin, lincomycin and clindamycin. The results from the broth dilution susceptibility testing of 39 of the isolates were compared with results obtained for the same isolates using the agar dilution method. Amongst the isolates tested by broth dilution, 17 were from three farms and had been collected over a number of years. Their pulsed field gel electrophoresis pattern previously had been determined. The broth dilution technique was simple to use, less labor intensive than agar dilution, and gave clear end points. The results obtained using the two methods generally corresponded well, although in a few cases the MIC obtained by broth dilution were lower than those with agar dilution. For the 76 isolates tested by broth dilution, the MIC(90) (mg/l) was: tiamulin, 1; valnemulin, 0.5; tylosin>256; erythromycin>256; lincomycin, 64 and clindamycin, 16. Only minor differences in susceptibility patterns were found amongst isolates from different Australian states. Over all the isolates, and also amongst the isolates obtained from different years on the three farms, there was no trend for the susceptibility of the isolates to alter with time. PMID:11731165

  20. High Performance Imaging Streak Camera for the National Ignition Facility

    SciTech Connect

    Opachich, Y. P.; Kalantar, D.; MacPhee, A.; Holder, J.; Kimbrough, J.; Bell, P. M.; Bradley, D.; Hatch, B.; Brown, C.; Landen, O.; Perfect, B. H.; Guidry, B.; Mead, A.; Charest, M.; Palmer, N.; Homoelle, D.; Browning, D.; Silbernagel, C.; Brienza-Larsen, G.; Griffin, M.; Lee, J. J.; Haugh, M. J.

    2012-01-01

    An x-ray streak camera platform has been characterized and implemented for use at the National Ignition Facility. The camera has been modified to meet the experiment requirements of the National Ignition Campaign and to perform reliably in conditions that produce high EMI. A train of temporal UV timing markers has been added to the diagnostic in order to calibrate the temporal axis of the instrument and the detector efficiency of the streak camera was improved by using a CsI photocathode. The performance of the streak camera has been characterized and is summarized in this paper. The detector efficiency and cathode measurements are also presented.

  1. Biological treatment of textile dyes by agar-agar immobilized consortium in a packed bed reactor.

    PubMed

    Patel, Yogesh; Gupte, Akshaya

    2015-03-01

    The decolorization of Acid Maroon V was investigated using bacterial consortium EDPA containing Enterobacter dissolvens AGYP1 and Pseudomonas aeruginosa AGYP2 immobilized in different entrapment matrices. The consortium displayed 96% removal of dye (100 mg/l) within 6 h when immobilized in agar-agar. Under optimum concentrations of agar-agar (3.0% w/v) and cell biomass (0.9 g% w/v), the consortium displayed decolorization for 18 successive batches of Acid Maroon V and also decolorized 14 other different textile dyes. A packed bed reactor under batch mode showed 89% decolorization of dye after 56 repetitive cycles. Under continuous flow mode, maximum color removal was achieved with bed length of 36 cm, hydraulic retention time of 2.66 h, and dye concentration of 100 mg/l. Additionally, the reactor decolorized relatively higher concentrations (100-2000 mg/l) of dye. The synthetic dye wastewater containing five textile dyes was decolorized 92% with 62% COD reduction using an immobilized consortium. PMID:25842535

  2. Temporal Contrast Changes in Dark Slope Streaks on Mars

    NASA Astrophysics Data System (ADS)

    Chilton, H.; Phillips, C. B.; Fenton, L. K.; Brown, A. J.

    2012-12-01

    Dark slope streaks on Mars, first observed in Viking images, provide insight into one of the most active and dynamic processes observed on the planet's surface. While various formation models have been suggested [1][2][3], dust avalanches seem to best explain streak origin and characteristics[4][5]. New dark streaks are observed to have the greatest contrast to their surroundings while older streaks have lower contrast, suggesting that streaks fade over time. One theory for this is atmospheric dust fallout slowly raising the albedo of the surface exposed by the dust avalanche, resulting in increased streak albedo over time until the streak becomes indistinguishable from the surrounding surface. In this study, we attempt an initial evaluation of changes in streak brightness relative to surroundings, with a first order correction for incidence angle[6] based on MOLA data. CRISM images were first identified for spatial and temporal overlap, then further selected for those image sets with well-matched viewing geometries. Locations included Nicholson Crater (CRISM images: frt0000c287_07_de165l, hrl0000d0f1_7_de165l, frt00018c69_07_de165l) and South of Nestus Valles (CRISM images: hrl00004a5e_07_de181l, hrl0000812a_07_de182l) as well as Naktong Vallis (CRISM images: hrl0000898d_07_de182l, hrl00005337_07_de182l) and an area in Lycus Sulci (CRISM images: hrl0000a52a_07_de166l, hrl0000ce5f_07_if175l). We focused on 1 micron wavelength CRISM images in order to reduce atmosphric interference. From here, brightness (observed radiance divided by solar irradiance at Mars divided by pi) values were collected along individual streaks, with measurements at multiple locations along the streak length and alongside at points of similar elevation to streak measurements to establish an average contrast ratio. Both on-streak and off-streak values were divided by the cosine of their respective local MOLA incidence angles to correct for brightness variation due to solar flux and

  3. Multicenter Investigation of Gepotidacin (GSK2140944) Agar Dilution Quality Control Determinations for Neisseria gonorrhoeae ATCC 49226.

    PubMed

    Jones, Ronald N; Fedler, Kelley A; Scangarella-Oman, Nicole E; Ross, James E; Flamm, Robert K

    2016-07-01

    Gepotidacin, a novel triazaacenaphthylene antibacterial agent, is the first in a new class of type IIA topoisomerase inhibitors with activity against many biothreat and conventional pathogens, including Neisseria gonorrhoeae To assist ongoing clinical studies of gepotidacin to treat gonorrhea, a multilaboratory quality assurance investigation determined the reference organism (N. gonorrhoeae ATCC 49226) quality control MIC range to be 0.25 to 1 μg/ml (88.8% of gepotidacin MIC results at the 0.5 μg/ml mode). PMID:27161642

  4. Recovery of spores of Clostridium botulinum in yeast extract agar and pork infusion agar after heat treatment.

    PubMed

    Odlaug, T E; Pflug, I J

    1977-10-01

    Yeast extract agar, pork infusion agar, and modifications of these media were used to recover heated Clostridium botulinum spores. The D- and z-values were determined. Two type A strains and one type B strain of C. botulinum were studied. In all cases the D-values were largest when the spores were recovered in yeast extract agar, compared to the D-values for spores recovered in pork infusion agar. The z-values for strains 62A and A16037 were largest when the spores were recovered in pork infusion agar. The addition of sodium bicarbonate and sodium thioglycolate to pork infusion agar resulted in D-values for C. botulinum 62A spores similar to those for the same spores recovered in yeast extract agar. The results suggest that sodium bicarbonate and sodium thioglycolate should be added to recovery media for heated C. botulinum spores to obtain maximum plate counts. PMID:335970

  5. Dilutions Made Easy.

    ERIC Educational Resources Information Center

    Kamin, Lawrence

    1996-01-01

    Presents problems appropriate for high school and college students that highlight dilution methods. Promotes an understanding of dilution methods in order to prevent the unnecessary waste of chemicals and glassware in biology laboratories. (JRH)

  6. Active Processes: Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

    In a region of the south pole known informally as 'Ithaca' numerous fans of dark frost form every spring. HiRISE collected a time lapse series of these images, starting at Ls = 185 and culminating at Ls = 294. 'Ls' is the way we measure time on Mars: at Ls = 180 the sun passes the equator on its way south; at Ls = 270 it reaches its maximum subsolar latitude and summer begins.

    In the earliest image (figure 1) fans are dark, but small narrow bright streaks can be detected. In the next image (figure 2), acquired at Ls = 187, just 106 hours later, dramatic differences are apparent. The dark fans are larger and the bright fans are more pronounced and easily detectable. The third image in the sequence shows no bright fans at all.

    We believe that the bright streaks are fine frost condensed from the gas exiting the vent. The conditions must be just right for the bright frost to condense.

    Observation Geometry Image PSP_002622_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 16-Feb-2007. The complete image is centered at -85.2 degrees latitude, 181.5 degrees East longitude. The range to the target site was 246.9 km (154.3 miles). At this distance the image scale is 49.4 cm/pixel (with 2 x 2 binning) so objects 148 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 05:46 PM and the scene is illuminated from the west with a solar incidence angle of 88 degrees, thus the sun was about 2 degrees above the horizon. At a solar longitude of 185.1 degrees, the season on Mars is Northern Autumn.

  7. Improving agar electrospinnability with choline-based deep eutectic solvents.

    PubMed

    Sousa, Ana M M; Souza, Hiléia K S; Uknalis, Joseph; Liu, Shih-Chuan; Gonçalves, Maria P; Liu, LinShu

    2015-09-01

    Very recently our group has produced novel agar-based fibers by an electrospinning technique using water as solvent and polyvinyl alcohol (PVA) as co-blending polymer. Here, we tested the deep eutectic solvent (DES), (2-hydroxyethyl)trimethylammonium chloride/urea prepared at 1:2 molar ratio, as an alternative solvent medium for agar electrospinning. The electrospun materials were collected with an ethanol bath adapted to a previous electrospinning set-up. One weight percent agar-in-DES showed improved viscoelasticity and hence, spinnability, when compared to 1 wt% agar-in-water and pure agar nanofibers were successfully electrospun if working above the temperature of sol-gel transition (∼80 °C). By changing the solvent medium we decreased the PVA concentration (5 wt% starting solution) and successfully produced composite fibers with high agar contents (50/50 agar/PVA). Best composite fibers were formed with the 50/50 and 30/70 agar/PVA solutions. These fibers were mechanically resistant, showed tailorable surface roughness and diverse size distributions, with most of the diameters falling in the sub-micron range. Both nano and micro forms of agar fibers (used separately or combined) may have potential for the design of new and highly functional agar-based materials. PMID:26116384

  8. Serial Dilution Simulation Lab

    ERIC Educational Resources Information Center

    Keler, Cynthia; Balutis, Tabitha; Bergen, Kim; Laudenslager, Bryanna; Rubino, Deanna

    2010-01-01

    Serial dilution is often a difficult concept for students to understand. In this short dry lab exercise, students perform serial dilutions using seed beads. This exercise helps students gain skill at performing dilutions without using reagents, bacterial cultures, or viral cultures, while being able to visualize the process.

  9. Poisoning with brown fly agaric, Amanita regalis.

    PubMed

    Elonen, E; Tarssanen, L; Härkönen, M

    1979-01-01

    Three patients ate different amounts of a common northern mushroom, brown fly agaric, Amanita regalis. All of them believed they had eaten delicious parasol mushrooms, Macrolepiota procera. The symptoms of poisoning began 1--2 hours after ingestion of the mushrooms. All the patients had marked gastrointestinal symptoms: nausea and heavy vomiting. Two had central nervous system manifestations and cholinergic symptoms: hallucinations, confusion, or loss of consciousness as well as copious salivation, or sweating. All patients recovered within 4--24 hours without any damage to liver, kidneys or central nervous system. It seems that cooking the mushrooms does not completely neutralize the toxic agents of Amanita regalis. The analysis of fried mushrooms shows that it may be possible to identify mushrooms reliably from the remains of a meal. PMID:760400

  10. Temporal Contrast Changes in Dark Slope Streaks on Mars

    NASA Astrophysics Data System (ADS)

    Chilton, Heather; Phillips, C. B.; Brown, A.; Fenton, L.

    2013-01-01

    Dark slope streaks on Mars are among the most active and dynamic processes observed on the planet's surface. While various formation models have been suggested [1][2][3], dust avalanches seem to best explain streak origin and characteristics[4][5]. New streaks have the highest contrast suggesting they fade over time. One theory for this is atmospheric dust fallout slowly raising the albedo of the surface exposed by the dust avalanche, progressively increasing streak albedo until the streak becomes indistinguishable from the surrounding surface. In this study, we attempt an initial evaluation of changes in streak brightness relative to surroundings with a first order correction for incidence angle[6]. CRISM images were identified for spatial overlap and temporal range, then further selected for image sets with well-matched viewing geometries. The 1 micron wavelength band was used to reduce atmospheric interference and brightness values then collected at multiple locations within and alongside individual streaks, with on-streak/off-streak pairs at points of similar elevation. Values were then divided by the cosine of the corresponding MOLA incidence angle for brightness variation correction due to topography. Measurements for overlapping images established local and overall averages for the rate of change in contrast ratio. Results showed a range of trends including streaks that darkened, brightened, brightened then darkened or vice versa. We continue to explore the possibility of non-linear brightening as well as streak reactivation and localized events, surface characteristics, and topography. Further study will focus on these and other morphological changes observed from vast data sets of other instruments including the Mars Reconnaissance Orbter HiRISE and CTX, Mars Express HRSC, Mars Odyssey THEMIS (visible), and the Mars Global Surveyor MOC. [1] Morris (1982) JGR, 87, 1164-1178. [2] Ferguson and Lucchita (1984) NASA Tech. Memo., TM-86246, 188-190. [3] Miyamoto

  11. Semiclassical model for attosecond angular streaking.

    PubMed

    Smolarski, M; Eckle, P; Keller, U; Dörner, R

    2010-08-16

    Attosecond angular streaking is a new technique to achieve unsurpassed time accuracy of only a few attoseconds. Recently this has been successfully used to set an upper limit on the electron tunneling delay time in strong laser field ionization. The measurement technique can be modeled with either the time-dependent Schrödinger equation (TDSE) or a more simple semiclassical approach that describes the process in two steps in analogy to the three-step model in high harmonic generation (HHG): step one is the tunnel ionization and step two is the classical motion in the strong laser field. Here we describe in detail a semiclassical model which is based on the ADK theory for the tunneling step, with subsequent classical propagation of the electron in the laser field. We take into account different ellipticities of the laser field and a possible wavelength-dependent ellipticity that is typically observed for pulses in the two-optical-cycle regime. This semiclassical model shows excellent agreement with the experimental result. PMID:20721150

  12. Simulation of FEL pulse length calculation with THz streaking method.

    PubMed

    Gorgisyan, I; Ischebeck, R; Prat, E; Reiche, S; Rivkin, L; Juranić, P

    2016-05-01

    Having accurate and comprehensive photon diagnostics for the X-ray pulses delivered by free-electron laser (FEL) facilities is of utmost importance. Along with various parameters of the photon beam (such as photon energy, beam intensity, etc.), the pulse length measurements are particularly useful both for the machine operators to measure the beam parameters and monitor the stability of the machine performance, and for the users carrying out pump-probe experiments at such facilities to better understand their measurement results. One of the most promising pulse length measurement techniques used for photon diagnostics is the THz streak camera which is capable of simultaneously measuring the lengths of the photon pulses and their arrival times with respect to the pump laser. This work presents simulations of a THz streak camera performance. The simulation procedure utilizes FEL pulses with two different photon energies in hard and soft X-ray regions, respectively. It recreates the energy spectra of the photoelectrons produced by the photon pulses and streaks them by a single-cycle THz pulse. Following the pulse-retrieval procedure of the THz streak camera, the lengths were calculated from the streaked spectra. To validate the pulse length calculation procedure, the precision and the accuracy of the method were estimated for streaking configuration corresponding to previously performed experiments. The obtained results show that for the discussed setup the method is capable of measuring FEL pulses with about a femtosecond accuracy and precision. PMID:27140142

  13. Simulation of FEL pulse length calculation with THz streaking method

    PubMed Central

    Gorgisyan, I.; Ischebeck, R.; Prat, E.; Reiche, S.; Rivkin, L.; Juranić, P.

    2016-01-01

    Having accurate and comprehensive photon diagnostics for the X-ray pulses delivered by free-electron laser (FEL) facilities is of utmost importance. Along with various parameters of the photon beam (such as photon energy, beam intensity, etc.), the pulse length measurements are particularly useful both for the machine operators to measure the beam parameters and monitor the stability of the machine performance, and for the users carrying out pump–probe experiments at such facilities to better understand their measurement results. One of the most promising pulse length measurement techniques used for photon diagnostics is the THz streak camera which is capable of simultaneously measuring the lengths of the photon pulses and their arrival times with respect to the pump laser. This work presents simulations of a THz streak camera performance. The simulation procedure utilizes FEL pulses with two different photon energies in hard and soft X-ray regions, respectively. It recreates the energy spectra of the photoelectrons produced by the photon pulses and streaks them by a single-cycle THz pulse. Following the pulse-retrieval procedure of the THz streak camera, the lengths were calculated from the streaked spectra. To validate the pulse length calculation procedure, the precision and the accuracy of the method were estimated for streaking configuration corresponding to previously performed experiments. The obtained results show that for the discussed setup the method is capable of measuring FEL pulses with about a femtosecond accuracy and precision. PMID:27140142

  14. Study of Geometric Parameters of Slope Streaks on Mars.

    NASA Astrophysics Data System (ADS)

    Brusnikin, Eugene; Kreslavsky, Mikhail; Karachevtseva, Irina; Zubarev, Anatoliy; Patratiy, Vyacheslav

    2015-04-01

    Slope streaks are a unique active phenomenon observed in low-latitude dusty regions on Mars. They are dark markings formed by an unknown type of run-away downslope propagation of surface disturbance. There are two kinds of hypotheses of their formation mechanism: "dry", involving granular follow, in particular, dust avalanche, and "wet", involving liquid flow, in particular, percolation of concentrated brines in shallow subsurface (1). Study of geometric characteristics of the slope streaks, especially their slopes, is a way to decipher their origin. We are carrying out an extensive set of measurements of geometric parameters of the slope streaks. We use stereo pairs of images obtained by High Resolution Imaging Science Experiment (HiRISE) onboard MRO orbital mission to Mars. These stereo pairs potentially allow geometric measurements (both horizontal and vertical) with accuracy on an order of a meter. Unfortunately, the digital terrain model is currently released for only one stereo pair in the regions of slope streak occurrence, and we have to work with raw, unprocessed stereo pairs. We perform direct photogrammetric measurements using PHOTOMOD software complex (http://www.racurs.ru/). We use our custom software to import "raw" HiRISE imgas (EDRs) and supplementary geometric information from SPICE into PHOTOMOD (2). We select tens to a hundred meters long segments in the beginning and the end of selected streaks and register length, azimuth, and slope of each segment. We also search for anomalously gentle parts of streaks. We analyze the obtained results by means of ESRI ArcGIS software. Our survey is in progress. So far we registered over a hundred of streaks. We found that the extent of the streaks varies from several meters to hundreds of meters. The streaks are formed in locales with a slope from 17 to 37 degrees. The lower boundary indicates that the streaks can propagate on slopes that are significantly gentler than the static angle of repose. Distal

  15. Susceptibility of a polycaprolactone-based root canal filling material to degradation using an agar-well diffusion assay

    PubMed Central

    Hiraishi, Noriko; Sadek, Fernanda T.; King, Nigel M.; Ferrari, Marco; Pashley, David H.; Tay, Franklin R

    2013-01-01

    Purpose Cholesterol esterase is both a component of salivary hydrolases as well as an inflammatory cell-derived enzyme and has been shown to cause biodegradation of methacrylate-based resin composites. This study examined whether Resilon, a polycaprolactone-based thermoplastic root filling material is susceptible to biodegradation by cholesterol esterase using agar-well diffusion assay of serially-diluted aqueous Resilon emulsions that were dispersed in agar. Materials and methods Emulsions of Resilon and polycaprolactone were prepared and dispersed in agar on culture plates. Two different concentrations of a cholesterol esterase (0.3 and 1.2 U/mL) were prepared and fed to wells prepared in the agar plates using an agar-well diffusion assay for examination the degradation of polymeric materials. Results Degradation of the emulsified Resilon was manifested as the formation of clear zones of different sizes around the agar wells. No clear zones were observed in agar wells that contain sterile distilled water as the negative control. Clinical significance Although dispersion Resilon into an emulsion is not the way in which this material is employed as a root filling material, the potential for Resilon to be degraded by cholesterol esterase is of potential concern as one cannot limit the degradation of extruded Resilon from a root apex by monocyte-derived macrophages to just the anatomical root apex. As the present study employed a high concentration of cholesterol esterase, further studies should be directed to examining the degradation of Resilon using macrophage cell cultures. PMID:18578181

  16. Streak detection and analysis pipeline for optical images

    NASA Astrophysics Data System (ADS)

    Virtanen, J.; Granvik, M.; Torppa, J.; Muinonen, K.; Poikonen, J.; Lehti, J.; Säntti, T.; Komulainen, T.; Flohrer, T.

    2014-07-01

    We describe a novel data processing and analysis pipeline for optical observations of moving objects, either of natural (asteroids, meteors) or artificial origin (satellites, space debris). The monitoring of the space object populations requires reliable acquisition of observational data to support the development and validation of population models, and to build and maintain catalogues of orbital elements. The orbital catalogues are, in turn, needed for the assessment of close approaches (for asteroids, with the Earth; for satellites, with each other) and for the support of contingency situations or launches. For both types of populations, there is also increasing interest to detect fainter objects corresponding to the small end of the size distribution. We focus on the low signal-to-noise (SNR) detection of objects with high angular velocities, resulting in long and faint object trails, or streaks, in the optical images. The currently available, mature image processing algorithms for detection and astrometric reduction of optical data cover objects that cross the sensor field-of-view comparably slowly, and, particularly for satellites, within a rather narrow, predefined range of angular velocities. By applying specific tracking techniques, the objects appear point-like or as short trails in the exposures. However, the general survey scenario is always a 'track-before-detect' problem, resulting in streaks of arbitrary lengths. Although some considerations for low-SNR processing of streak-like features are available in the current image processing and computer vision literature, algorithms are not readily available yet. In the ESA-funded StreakDet (Streak detection and astrometric reduction) project, we develop and evaluate an automated processing pipeline applicable to single images (as compared to consecutive frames of the same field) obtained with any observing scenario, including space-based surveys and both low- and high-altitude populations. The algorithmic

  17. Microfluidic serial dilution ladder.

    PubMed

    Ahrar, Siavash; Hwang, Michelle; Duncan, Philip N; Hui, Elliot E

    2014-01-01

    Serial dilution is a fundamental procedure that is common to a large number of laboratory protocols. Automation of serial dilution is thus a valuable component for lab-on-a-chip systems. While a handful of different microfluidic strategies for serial dilution have been reported, approaches based on continuous flow mixing inherently consume larger amounts of sample volume and chip real estate. We employ valve-driven circulatory mixing to address these issues and also introduce a novel device structure to store each stage of the dilution process. The dilution strategy is based on sequentially mixing the rungs of a ladder structure. We demonstrate a 7-stage series of 1 : 1 dilutions with R(2) equal to 0.995 in an active device area of 1 cm(2). PMID:24231765

  18. The Resazurin-Agar Method - a Quick Test to Determine Water Quality

    NASA Astrophysics Data System (ADS)

    Huckfeldt, J.; Westphal, B.; Claußen, L.

    2015-12-01

    Rezasurin has been used as a smart tracer in stream ecosystems to indicate metabolic activity, specifically aerobic respiration by heterotrophic bacteria. Resazurin is a blue compound which is irreversibly reduced to the pink resorufin in the presence of aerobic bacteria. The degree and speed of colour change from blue to pink is a measure of the degree of oxygen consumption and thus an indirect indication of the concentration of aerobic bacteria in a given medium. A high concentration of bacteria in water indicates a bad water quality. In our work a method was developed using resazurin agar plates to find a quick and easy way for testing water quality and comparing concentrations of bacteria in freshwater and seawater samples. The theory was to concentrate bacteria from a defined volume of water sample onto polycarbonate filters (0.2 μm), which are then placed onto the resazurin agar plate. The presence of aerobic bacteria on the filter will reduce the resazurin in the agar and the compound changes its colour. First tests conducted with different dilutions of a pure culture of yoghurt bacteria showed promising results and confirmed the feasibility of the method. In a further assay, we used water samples from different water layers and different temperatures and were also able to observe differences in the concentration of bacteria, depending on these different environmental conditions.The assay was also successfully used with seawater samples, collected from 2 different stations at 3 different depths in the Baltic Sea (salinity=15). The discolouration of the plates showed good correlation with the oxygen concentrations in the water. The resazurin-agar plate method is economical and fast. Several samples could be investigated at the same time without sacrificing the reliability of the results. Thus it is a good pre-screening test for a quantitative evaluation of bacteria in a water sample.

  19. Hitting Is Contagious in Baseball: Evidence from Long Hitting Streaks

    PubMed Central

    Bock, Joel R.; Maewal, Akhilesh; Gough, David A.

    2012-01-01

    Data analysis is used to test the hypothesis that “hitting is contagious”. A statistical model is described to study the effect of a hot hitter upon his teammates’ batting during a consecutive game hitting streak. Box score data for entire seasons comprising streaks of length games, including a total observations were compiled. Treatment and control sample groups () were constructed from core lineups of players on the streaking batter’s team. The percentile method bootstrap was used to calculate confidence intervals for statistics representing differences in the mean distributions of two batting statistics between groups. Batters in the treatment group (hot streak active) showed statistically significant improvements in hitting performance, as compared against the control. Mean for the treatment group was found to be to percentage points higher during hot streaks (mean difference increased points), while the batting heat index introduced here was observed to increase by points. For each performance statistic, the null hypothesis was rejected at the significance level. We conclude that the evidence suggests the potential existence of a “statistical contagion effect”. Psychological mechanisms essential to the empirical results are suggested, as several studies from the scientific literature lend credence to contagious phenomena in sports. Causal inference from these results is difficult, but we suggest and discuss several latent variables that may contribute to the observed results, and offer possible directions for future research. PMID:23251507

  20. Design and Field Test of a Galvanometer Deflected Streak Camera

    SciTech Connect

    Lai, C C; Goosman, D R; Wade, J T; Avara, R

    2002-11-08

    We have developed a compact fieldable optically-deflected streak camera first reported in the 20th HSPP Congress. Using a triggerable galvanometer that scans the optical signal, the imaging and streaking function is an all-optical process without incurring any photon-electron-photon conversion or photoelectronic deflection. As such, the achievable imaging quality is limited mainly only by optical design, rather than by multiple conversions of signal carrier and high voltage electron-optics effect. All core elements of the camera are packaged into a 12 inch x 24 inch footprint box, a size similar to that of a conventional electronic streak camera. At LLNL's Site-300 Test Site, we have conducted a Fabry-Perot interferometer measurement of fast object velocity using this all-optical camera side-by-side with an intensified electronic streak camera. These two cameras are configured as two independent instruments for recording synchronously each branch of the 50/50 splits from one incoming signal. Given the same signal characteristics, the test result has undisputedly demonstrated superior imaging performance for the all-optical streak camera. It produces higher signal sensitivity, wider linear dynamic range, better spatial contrast, finer temporal resolution, and larger data capacity as compared with that of the electronic counterpart. The camera had also demonstrated its structural robustness and functional consistence to be well compatible with field environment. This paper presents the camera design and the test results in both pictorial records and post-process graphic summaries.

  1. The Dellistrique 2S - A 200 Channel Streak Camera

    NASA Astrophysics Data System (ADS)

    Majumdar, S.

    1985-02-01

    Despite a great deal of effort to improve time resolution of streak cameras, the best reported time resolution remained just under one picosecond for more than a decade. However, the sensitivity and resolution of these devices have improved substantially over this time. In this paper the design of a very high performance streak camera, capable of resolving one picosecond on 200 parallel channels with single photo-electron detection capability: the Dellistrique 2S. The system comprises of a streak tube type Picotron 200 with a photocathode resolving 200 spatial channels along a slit and with an extraction field near the photocathode of greater than 16 KV per cm and with a non saturating phosphor screen as the main component. There is post streak tube intensification of 30,000 at the streak tube output wavelength which increases both the sensitivity of the system. The intensifier is coupled to a CCD readout device fibre-optically for producing a two dimensional image with a dynamic range of greater than 500. The camera can be operated at a repetition rate of between 80 MHz and 240 MHz using R.F. scanning methods. Upto 20 parallel channels have been tried with parallel information recording, which is well below the tube's capability of recording 200 independent channels. The image is virtually distortion free across the whole usable screen length of 45 mm for a large screen tube.

  2. Selected elements in fly agaric Amanita muscaria.

    PubMed

    Falandysz, J; Kunito, T; Kubota, R; Lipka, K; Mazur, A; Falandysz, Justyna J; Tanabe, S

    2007-09-01

    Concentrations of Ag, Al, Ba, Ca, Cd, Co, Cu, Cr, Cs, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Pb, Rb, Se, Sb, Sr, V, Tl and Zn have been determined in the whole fruiting bodies, as well as separately in caps and stalks, of fly agaric collected from three geographically distant sites in northern part of Poland. The elements were determined using ICP-MS, ICP-OES, HG-AAS and CV-AAS, respectively. For elements such as Al, Ba, Cr, Fe, Ga, Mo, Mn, Pb, Sb, Sr, Tl, and V concentrations were similar in the caps and stalks, respectively, and for K, Zn, Ag, Ca, Cd, Cu, Hg, Mg, Rb and Se were greater in the caps, while for Co, Cs and Na in the stalks. For Ag, Al, Ba, Ca, Cd, Co, Cr, Cs, Fe, Ga, Hg, Mn, Mo, Pb, Rb, Sb, Sr, Tl and V concentration in the caps showed spatial variations (P<0.05), while for Cu, K, Mg, Na, Se and Zn was independent of the site. The elements such as K with median or mean in the caps between 37,000 and 43,000 microg/g.dm and Mg with 920 and 1,100 microg/g dm were most abundant. Next, within median values range from approximately 100 to 500 microg/g dm were such as Ca, Fe and Al, and in descending order they followed by Rb (100-400 microg/g dm); V, Na, Zn (50-200 microg/g dm); Cu, Mn (10-50 microg/g dm); Cd (10-20 microg/g dm); Se (5 microg/g dm); Ba (<1-3); Cr, Ag, Pb, Sr (<1-2 microg/g dm); Cs, Co, Hg (<1-1 microg/g dm); Ga (<0.5), Sb, Mo and Tl (<0.1 microg/g dm). PMID:17849303

  3. A time-resolved image sensor for tubeless streak cameras

    NASA Astrophysics Data System (ADS)

    Yasutomi, Keita; Han, SangMan; Seo, Min-Woong; Takasawa, Taishi; Kagawa, Keiichiro; Kawahito, Shoji

    2014-03-01

    This paper presents a time-resolved CMOS image sensor with draining-only modulation (DOM) pixels for tube-less streak cameras. Although the conventional streak camera has high time resolution, the device requires high voltage and bulky system due to the structure with a vacuum tube. The proposed time-resolved imager with a simple optics realize a streak camera without any vacuum tubes. The proposed image sensor has DOM pixels, a delay-based pulse generator, and a readout circuitry. The delay-based pulse generator in combination with an in-pixel logic allows us to create and to provide a short gating clock to the pixel array. A prototype time-resolved CMOS image sensor with the proposed pixel is designed and implemented using 0.11um CMOS image sensor technology. The image array has 30(Vertical) x 128(Memory length) pixels with the pixel pitch of 22.4um. .

  4. Attosecond streaking in a nano-plasmonic field

    NASA Astrophysics Data System (ADS)

    Kelkensberg, F.; Koenderink, A. F.; Vrakking, M. J. J.

    2012-09-01

    A theoretical study of the application of attosecond streaking spectroscopy to time-resolved studies of the plasmonic fields surrounding isolated, resonantly excited spherical nanoparticles is presented. A classification of the different regimes in attosecond streaking is proposed and identified in our results that are derived from Mie calculations of plasmon fields, coupled to classical electron trajectory simulations. It is shown that in an attosecond streaking experiment, the electrons are almost exclusively sensitive to the component of the field parallel to the direction in which they are detected. This allows one to probe the different components of the field individually by resolving the angle of emission of the electrons. Finally, simulations based on fields calculated by finite-difference time-domain (FDTD) are compared with the results obtained using Mie fields. The two are found to be in good agreement with each other, supporting the notion that FDTD methods can be used to reliably investigate non-spherical structures.

  5. Mead Crater, Venus - Aerodynamic roughness of wind streaks

    NASA Astrophysics Data System (ADS)

    Williams, K. K.; Greeley, R.

    1997-03-01

    Radar backscatter images of Venus returned by the Magellan spacecraft revealed many aeolian features on the planet's surface. While much work has focused on terrestrial wind streaks, the harsh environment of Venus limits direct measurement of surface properties, such as aerodynamic roughness, that affect aeolian features on that planet. However, a correlation between radar backscatter and aerodynamic roughness (Z0) for the S-band radar system on Magellan can be used to study the aerodynamic roughnesses of areas in which Venusian wind streaks occur. The aerodynamic roughness of areas with both radar-bright and radar-dark wind streaks near Mead crater are calculated and compared to z0 values measured on Earth in order to compare the surface of Venus with known terrestrial surface textures.

  6. Streak Camera Performance with Large-Format CCD Readout

    SciTech Connect

    Lerche, R A; Andrews, D S; Bell, P M; Griffith, R L; McDonald, J W; Torres, P III; Vergel de Dios, G

    2003-07-08

    The ICF program at Livermore has a large inventory of optical streak cameras that were built in the 1970s and 1980s. The cameras include micro-channel plate image-intensifier tubes (IIT) that provide signal amplification and early lens-coupled CCD readouts. Today, these cameras are still very functional, but some replacement parts such as the original streak tube, CCD, and IIT are scarce and obsolete. This article describes recent efforts to improve the performance of these cameras using today's advanced CCD readout technologies. Very sensitive, large-format CCD arrays with efficient fiber-optic input faceplates are now available for direct coupling with the streak tube. Measurements of camera performance characteristics including linearity, spatial and temporal resolution, line-spread function, contrast transfer ratio (CTR), and dynamic range have been made for several different camera configurations: CCD coupled directly to the streak tube, CCD directly coupled to the IIT, and the original configuration with a smaller CCD lens coupled to the IIT output. Spatial resolution (limiting visual) with and without the IIT is 8 and 20 lp/mm, respectively, for photocathode current density up to 25% of the Child-Langmuir (C-L) space-charge limit. Temporal resolution (fwhm) deteriorates by about 20% when the cathode current density reaches 10% of the C-L space charge limit. Streak tube operation with large average tube current was observed by illuminating the entire slit region through a Ronchi ruling and measuring the CTR. Sensitivity (CCD electrons per streak tube photoelectron) for the various configurations ranged from 7.5 to 2,700 with read noise of 7.5 to 10.5 electrons. Optimum spatial resolution is achieved when the IIT is removed. Maximum dynamic range requires a configuration where a single photoelectron from the photocathode produces a signal that is 3 to 5 times the read noise.

  7. Wheat streak mosaic virus-Structural parameters for a Potyvirus

    SciTech Connect

    Parker, Lauren; Kendall, Amy; Berger, P.H.; Shiel, P.J.; Stubbs, Gerald . E-mail: gerald.stubbs@vanderbilt.edu

    2005-09-15

    Wheat streak mosaic virus is a Tritimovirus, a member of the Potyviridae family, which includes the very large Potyvirus genus. We have examined wheat streak mosaic virus by electron microscopy and fiber diffraction from partially oriented sols, and analyzed the results to estimate the symmetry and structural parameters of the viral helix. The virions have an apparent radius of 63 {+-} 5 A. The viral helix has a pitch of 33.4 A {+-} 0.6 A. There appear to be 6.9 subunits per turn of the helix, although we cannot completely eliminate values of 5.9 or 7.9 for this parameter.

  8. Hot streaks and phantom cooling in a turbine rotor passage. I - Separate effects

    NASA Technical Reports Server (NTRS)

    Roback, Richard J.; Dring, Robert P.

    1992-01-01

    Experimental documentation and analytical correlations demonstrating the effects of hot streak accumulation and phantom cooling on turbine rotor airfoil surface temperature. Test results are shown for a range of controlling variables to identify where streak accumulation and phantom cooling are most likely to be strongest. These variables include streak injection location, streak-to-free stream density ratio and coolant-to-free stream density and velocity ratios.

  9. Simplified 48-hour IMVic test: an agar plate method.

    PubMed

    Powers, E M; Latt, T G

    1977-09-01

    An agar plate method was developed for the performance of the IMVic (indole, methyl red, Voges-Proskauer, and citrate) tests in lieu of the conventional tubed liquid media. By modifying the composition of the media and adding agar, a single "X"-compartmented petri dish was prepared containing all four IMVic test media. Ease of performance and simplification of the test were achieved by inoculating all four media simultaneously from a single colony (single inoculum) on eosin-methylene blue agar. Tests with 87 cultures, representing 7 genera in the family Enterobacteriaceae, were completed with typical (correct) IMVic patterns for all cultures within 48 h. Parallel tests with conventional media showed that the agar plate method was superior, more sensitive, faster, and simpler to perform, and less time was required to identify Escherichia coli by 72 h. PMID:334074

  10. Processing Particle-Streak Imagery On A Personal Computer

    NASA Technical Reports Server (NTRS)

    Cho, Y. C.; Mclachlan, B. G.

    1991-01-01

    Report describes simple flow experiment in which streak images of particles suspended in fluid and illuminated for short times processed into maps of velocity vectors. In experiment, semiautomatic data-reduction scheme used which recovers significant image data more efficiently than currently available automatic scheme.

  11. Soft x-ray streak camera for laser fusion applications

    SciTech Connect

    Stradling, G.L.

    1981-04-01

    This thesis reviews the development and significance of the soft x-ray streak camera (SXRSC) in the context of inertial confinement fusion energy development. A brief introduction of laser fusion and laser fusion diagnostics is presented. The need for a soft x-ray streak camera as a laser fusion diagnostic is shown. Basic x-ray streak camera characteristics, design, and operation are reviewed. The SXRSC design criteria, the requirement for a subkilovolt x-ray transmitting window, and the resulting camera design are explained. Theory and design of reflector-filter pair combinations for three subkilovolt channels centered at 220 eV, 460 eV, and 620 eV are also presented. Calibration experiments are explained and data showing a dynamic range of 1000 and a sweep speed of 134 psec/mm are presented. Sensitivity modifications to the soft x-ray streak camera for a high-power target shot are described. A preliminary investigation, using a stepped cathode, of the thickness dependence of the gold photocathode response is discussed. Data from a typical Argus laser gold-disk target experiment are shown.

  12. Silent polypoidal choroidal vasculopathy in a patient with angioid streaks.

    PubMed

    Cebeci, Zafer; Bayraktar, Serife; Oray, Merih; Kir, Nur

    2016-01-01

    We present a case of silent polypoidal choroidal vasculopathy (PCV) in a patient with angioid streaks. PCV was detected during a routine ophthalmic examination and confirmed by fluorescein angiography, indocyanine green angiography, and optical coherence tomography. After 2 years of follow-up, the PCV remained silent without any complications. We report this rare coexistence and review literature on this topic. PMID:27463636

  13. Improved approach to characterizing and presenting streak camera performance

    SciTech Connect

    Wiedwald, J.D.; Jones, B.A.

    1985-07-15

    The performance of a streak camera recording system is strongly linked to the technique used to amplify, detect and quantify the streaked image. At the Lawrence Livermore National Laboratory (LLNL) streak camera images have been recorded both on film and by fiber-optically coupling to charge-coupled devices (CCD's). During the development of a new process for recording these images (lens coupling the image onto a cooled CCD) the definitions of important performance characteristics such as resolution and dynamic range were re-examined. As a result of this development, these performance characteristics are now presented to the streak camera user in a more useful format than in the past. This paper describes how these techniques are used within the Laser Fusion Program at LLNL. The system resolution is presented as a modulation transfer function, including the seldom reported effects that flare and light scattering have at low spatial frequencies. Data are presented such that a user can adjust image intensifier gain and pixel averaging to optimize the useful dynamic range in any particular application.

  14. Analysis of hot streak effects on turbine rotor heat load

    SciTech Connect

    Shang, T.; Epstein, A.H.

    1997-07-01

    The influence of inlet hot streak temperature distortion on turbine blade heat load was explored on a transonic axial flow turbine stage test article using a three-dimensional, multiblade row unsteady Euler code. The turbine geometry was the same as that used for a recently reported testing of hot streak influence. Emphasis was placed on elucidating the physical and mechanisms by which hot streaks affect turbine durability. It was found that temperature distortion significantly increases both blade surface heat load nonuniformity and total blade heat load by as much as 10--30% (mainly in the pressure surface), and that the severity of this influence is a strong function of turbine geometry and flow conditions. Three physical mechanisms were identified that drive the heat load nonuniformity: buoyancy, wake convection (the Kerrebrock-Mikolajczak effect), and rotor-stator interactions. The latter can generate significant nonuniformity of the time-averaged relative frame rotor inlet temperature distribution. Dependence of these effects on turbine design variables was investigated to shed light on the design space, which minimizes the adverse effects of hot streaks.

  15. Attosecond time-resolved streaked photoemission from solids

    NASA Astrophysics Data System (ADS)

    Liao, Qing; Thumm, Uwe

    2015-05-01

    We established a quantum-mechanical model for infrared (IR) laser streaked photoelectron (PE) emission from metal solids by an ultrashort extreme ultraviolet (XUV) pulse. Special emphasis was laid on the influence of the energy dispersion of PEs inside the solids on the photoemission time delay. We first applied this model to Mg(0001) surfaces, assuming free-electron dispersion and found good agreement with measured streaked PE spectra and streaking time delays. Next, we investigate W(110) surfaces for which non-free PE dispersion must be included in order to reproduce the measured photoemission delays at different XUV central photon energies. Our model reproduces a series of measured streaked spectrograms and photoemission delays for different metal solids, including clean Mg(0001) and W(110) surfaces and Mg-covered W(110) surfaces. It incorporates modeling of the target band structure, electron mean free paths, energy dispersion, and screening of the IR laser field on the surface. Supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy under Grant No. DE-FG02-86ER13491 and NSF Grant PHY-1068752.

  16. Reliable and Repeatable Characterization of Optical Streak Cameras

    SciTech Connect

    Michael Charest Jr., Peter Torres III, Christopher Silbernagel, and Daniel Kalantar

    2008-10-31

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser experiments at facilities such as the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electrical components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases, the characterization data are applied to the raw data images to correct for the nonlinearities. In order to characterize an optical streak camera, a specific set of data is collected, where the response to defined inputs are recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, and temporal resolution from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information.

  17. Reliable and Repeatable Characterication of Optical Streak Cameras

    SciTech Connect

    Kalantar, D; Charest, M; Torres III, P; Charest, M

    2008-05-06

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser experiments at facilities such as the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electrical components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases, the characterization data are applied to the raw data images to correct for the nonlinearities. In order to characterize an optical streak camera, a specific set of data is collected, where the response to defined inputs are recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, and temporal resolution from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information.

  18. Thermal characterization of magnetically aligned carbonyl iron/agar composites.

    PubMed

    Diaz-Bleis, D; Vales-Pinzón, C; Freile-Pelegrín, Y; Alvarado-Gil, J J

    2014-01-01

    Composites of magnetic particles into polymeric matrices have received increasing research interest due to their capacity to respond to external magnetic or electromagnetic fields. In this study, agar from Gelidium robustum has been chosen as natural biocompatible polymer to build the matrix of the magnetic carbonyl iron particles (CIP) for their uses in biomedical fields. Heat transfer behavior of the CIP-agar composites containing different concentrations (5, 10, 15, 20, 25 and 30% w/w) of magnetically aligned and non-aligned CIP in the agar matrix was studied using photothermal radiometry (PTR) in the back-propagation emission configuration. The morphology of the CIP-agar composites with aligned and non-aligned CIP under magnetic field was also evaluated by scanning electron microscopy (SEM). The results revealed a dominant effect of CIP concentration over the alignment patterns induced by the magnetic field, which agrees with the behavior of the thermal diffusivity and thermal conductivity. Agar served as a perfect matrix to be used with CIP, and CIP-agar composites magnetically aligned at 20% CIP concentration can be considered as promising 'smart' material for hyperthermia treatments in the biomedical field. PMID:24274482

  19. Hitting is contagious in baseball: evidence from long hitting streaks.

    PubMed

    Bock, Joel R; Maewal, Akhilesh; Gough, David A

    2012-01-01

    Data analysis is used to test the hypothesis that "hitting is contagious". A statistical model is described to study the effect of a hot hitter upon his teammates' batting during a consecutive game hitting streak. Box score data for entire seasons comprising [Formula: see text] streaks of length [Formula: see text] games, including a total [Formula: see text] observations were compiled. Treatment and control sample groups ([Formula: see text]) were constructed from core lineups of players on the streaking batter's team. The percentile method bootstrap was used to calculate [Formula: see text] confidence intervals for statistics representing differences in the mean distributions of two batting statistics between groups. Batters in the treatment group (hot streak active) showed statistically significant improvements in hitting performance, as compared against the control. Mean [Formula: see text] for the treatment group was found to be [Formula: see text] to [Formula: see text] percentage points higher during hot streaks (mean difference increased [Formula: see text] points), while the batting heat index [Formula: see text] introduced here was observed to increase by [Formula: see text] points. For each performance statistic, the null hypothesis was rejected at the [Formula: see text] significance level. We conclude that the evidence suggests the potential existence of a "statistical contagion effect". Psychological mechanisms essential to the empirical results are suggested, as several studies from the scientific literature lend credence to contagious phenomena in sports. Causal inference from these results is difficult, but we suggest and discuss several latent variables that may contribute to the observed results, and offer possible directions for future research. PMID:23251507

  20. Characterization of agar/soy protein biocomposite films: Effect of agar on the extruded pellets and compression moulded films.

    PubMed

    Garrido, T; Etxabide, A; Guerrero, P; de la Caba, K

    2016-10-20

    Agar/soy protein biocomposite films were successfully processed by extrusion and compression moulding, obtaining transparent and homogeneous films. The conformational changes occurred during the extrusion process and the effect of agar on the final properties were analyzed. As shown by differential scanning calorimetry (DSC) and specific mechanical energy (SME) values, during the extrusion process protein denatured and unfolded protein chains could interact with agar. These interactions were analyzed by Fourier transform infrared spectroscopy (FTIR) and the secondary structure was determined from the amide I band. Those interactions were supported by the decrease of film solubility. Furthermore, the good compatibility between agar and soy protein was confirmed by the images from scanning electron microscopy (SEM). PMID:27474583

  1. Ipomoviruses: Squash vein yellowing virus, Cucumber vein yellowing virus, Cassava brown streak virus, and Ugandan cassava brown streak virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ipomoviruses including Squash vein yellowing virus, Cucumber vein yellowing virus and Cassava brown streak virus are currently causing significant economic impact on crop production in several regions of the world. Only recently have results of detailed characterization of their whitefly transmissi...

  2. Monitoring Nonadiabatic Electron-Nuclear Dynamics in Molecules by Attosecond Streaking of Photoelectrons.

    PubMed

    Kowalewski, Markus; Bennett, Kochise; Rouxel, Jérémy R; Mukamel, Shaul

    2016-07-22

    Streaking of photoelectrons has long been used for the temporal characterization of attosecond extreme ultraviolet pulses. When the time-resolved photoelectrons originate from a coherent superposition of electronic states, they carry additional phase information, which can be retrieved by the streaking technique. In this contribution we extend the streaking formalism to include coupled electron and nuclear dynamics in molecules as well as initial coherences. We demonstrate how streaked photoelectrons offer a novel tool for monitoring nonadiabatic dynamics as it occurs in the vicinity of conical intersections and avoided crossings. Streaking can provide high time resolution direct signatures of electronic coherences, which affect many primary photochemical and biological events. PMID:27494470

  3. Monitoring Nonadiabatic Electron-Nuclear Dynamics in Molecules by Attosecond Streaking of Photoelectrons

    NASA Astrophysics Data System (ADS)

    Kowalewski, Markus; Bennett, Kochise; Rouxel, Jérémy R.; Mukamel, Shaul

    2016-07-01

    Streaking of photoelectrons has long been used for the temporal characterization of attosecond extreme ultraviolet pulses. When the time-resolved photoelectrons originate from a coherent superposition of electronic states, they carry additional phase information, which can be retrieved by the streaking technique. In this contribution we extend the streaking formalism to include coupled electron and nuclear dynamics in molecules as well as initial coherences. We demonstrate how streaked photoelectrons offer a novel tool for monitoring nonadiabatic dynamics as it occurs in the vicinity of conical intersections and avoided crossings. Streaking can provide high time resolution direct signatures of electronic coherences, which affect many primary photochemical and biological events.

  4. Charcoal agar, a new growth medium for the fish disease bacterium Renibacterium salmoninarum.

    PubMed Central

    Daly, J G; Stevenson, R M

    1985-01-01

    Charcoal is an effective replacement for serum in media for the isolation and culture of Renibacterium salmoninarum, the causative agent of bacterial kidney disease in salmonid fish. The medium, KDM-C, contains 10 g of peptone, 0.5 g of yeast extract, 1 g of L-cysteine hydrochloride, 1 g of activated charcoal, and 15 g of agar per liter and is adjusted to pH 6.8 with NaOH before autoclaving. Eight strains of R. salmoninarum grew from dilute inocula as well on KDM-C as on a standard serum-containing medium (KDM-2). The medium was effective for both primary isolations from fish and repeated transfers and has potential value for antigen preparation and physiological studies. Images PMID:4083882

  5. Hyperspectral imaging for detecting pathogens grown on agar plates

    NASA Astrophysics Data System (ADS)

    Yoon, Seung Chul; Lawrence, Kurt C.; Siragusa, Gregory R.; Line, John E.; Park, Bosoon; Windham, William R.

    2007-09-01

    This paper is concerned with the development of a hyperspectral imaging technique for detecting and identifying one of the most common foodborne pathogens, Campylobacter. Direct plating using agars is an effective tool for laboratory tests and analyses of microorganisms. The morphology (size, growth pattern, color, etc.) of colonies grown on agar plates has been widely used to tentatively differentiate organisms. However, it is sometimes difficult to differentiate target organisms like Campylobacters from other contaminants grown together on the same agar plates. A hyperspectral imaging system operating at the visible and near infrared (VNIR) spectral region from 400 nm to 900 nm was set up to measure spectral signatures of 17 different Campylobacter and non-Campylobacter subspecies. Protocols for culturing, imaging samples and for calibrating measured data were developed. The VNIR spectral library of all 17 organisms commonly encountered in poultry was established from calibrated hyperspectral images. A classification algorithm was developed to locate and identify Campylobacters, non-Campylobacter contaminants, and background agars with 99.29% accuracy. This research has a potential to be expanded to detect other pathogens grown on agar media.

  6. Development of streak camera with anisotropic focusing electron optical system

    NASA Astrophysics Data System (ADS)

    Tian, J.; Ding, Y.; Cao, X.; Liu, S.; Xu, X.; Hu, X.; Wen, W.; Wang, J.; Wang, C.; Liu, H.; Dong, G.; Zhang, T.; Lu, Y.; Wang, Xi.; Liu, J.

    2013-05-01

    In this paper, the anisotropic focusing technique is used to make a novel streak tube. The salient features are the introduction of both temporally focusing electrodes and spatially focusing electric quadrupole lens. The simulation showed that physical temporal dispersion of 0.38 ps and edge spatial resolution of 56 lp/mm can be achieved. The Nd:YLF 8ps pulse laser was used to calibrate the performance index of streak camera. The static and dynamic spatial resolutions are 35 lp/mm and 25 lp/mm respectively. The dynamic range more than 950:1 and time resolution 8ps can be reached. Furthermore, the magnifications in slit and scanning direction can be adjusted respectively, so it is very convenient to select amplification needed when it is coupled with KB microscope.

  7. Megahertz streak-mode Fourier domain optical coherence tomography

    PubMed Central

    Wang, Rui; Yun, Julie X.; Yuan, Xiaocong; Goodwin, Richard; Markwald, Roger R.; Gao, Bruce Z.

    2011-01-01

    Here we present an ultrahigh-speed Fourier-domain optical coherence tomography (OCT) that records the OCT spectrum in streak mode with a high-speed area scan camera, which allows higher OCT imaging speed than can be achieved with a line-scan camera. Unlike parallel OCT techniques that also use area scan cameras, the conventional single-mode fiber-based point-scanning mechanism is retained to provide a confocal gate that rejects multiply scattered photons from the sample. When using a 1000 Hz resonant scanner as the streak scanner, 1,016,000 A-scans have been obtained in 1 s. This method's effectiveness has been demonstrated by recording in vivo OCT-image sequences of embryonic chick hearts at 1000 frames/s. In addition, 2-megahertz OCT data have been obtained with another high speed camera. PMID:21721817

  8. Streak cameras for soft x-ray and optical radiation

    SciTech Connect

    Medecki, H.

    1983-09-01

    The principal component of a streak camera is the image converter tube. A slit-shaped photocathode transforms the radiation into a proportional emission of electrons. An electron - optics arrangement accelerates the electrons and projects them into a phosphor screen creating the image of the slit. A pair of deflection plates deflects the electronic beam along a direction perpendicular to the main dimension of the slit. Different portions of the phosphor screen show the instantaneous image of the slit with brightness proportional to the number of emitted electrons and, consequently, to the intensity of the radiation. For our x-ray streak cameras, we use the RCA C73435A image conventer tube intended for the measurement of the radiation of light and modified to have an x-ray sensitive photocathode. Practical considerations lead to the use of transparent rather than reflecting photocathodes. Several of these camera tubes are briefly described.

  9. rf streak camera based ultrafast relativistic electron diffraction.

    PubMed

    Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Tran, T

    2009-01-01

    We theoretically and experimentally investigate the possibility of using a rf streak camera to time resolve in a single shot structural changes at the sub-100 fs time scale via relativistic electron diffraction. We experimentally tested this novel concept at the UCLA Pegasus rf photoinjector. Time-resolved diffraction patterns from thin Al foil are recorded. Averaging over 50 shots is required in order to get statistics sufficient to uncover a variation in time of the diffraction patterns. In the absence of an external pump laser, this is explained as due to the energy chirp on the beam out of the electron gun. With further improvements to the electron source, rf streak camera based ultrafast electron diffraction has the potential to yield truly single shot measurements of ultrafast processes. PMID:19191429

  10. 9. VIEW OF 'BLUE STREAK' HAMMER MILL (Prater Pulverizer Co., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW OF 'BLUE STREAK' HAMMER MILL (Prater Pulverizer Co., Chicago, Illinois), LOCATED IN THE SOUTHEAST CORNER OF THE BASEMENT, WAS ADDED IN THE EARLY 1930s. THIS WAS THE MILL'S FIRST ELECTRIC-POWERED MACHINERY. THE HAMMER MILL WAS USED TO PULVERIZE OATS, ALFALFA MEAL, AND CORN. Photographer: Louise Taft Cawood, July 1986 - Alexander's Grist Mill, Lock 37 on Ohio & Erie Canal, South of Cleveland, Valley View, Cuyahoga County, OH

  11. Fly agaric (Amanita muscaria) poisoning, case report and review.

    PubMed

    Satora, Leszek; Pach, Dorota; Butryn, Beata; Hydzik, Piotr; Balicka-Slusarczyk, Barbara

    2005-06-01

    Gathering and eating mushrooms and other plants containing psychoactive substances has become increasingly popular among young people experimenting with drugs. Dried fly agaric Amanita muscaria fruiting bodies were eaten by five young persons (18-21 years of age) at a party in order to evoke hallucinations. Visual and auditory hallucinations occurred in four of them, whereas a 18-year-old girl lost consciousness. The following morning, she went to the Clinic of Toxicology. Due to the fact that not all the active substances present in the fly agaric have been identified, and some of them have an effect after a period of latency, the patient was admitted for several days of observation during which check-up examinations were performed. After four days without any problems, she was discharged. The poisoning regressed with no organ complications. The remaining persons who had eaten the fly agaric were free from any complaints. PMID:15904689

  12. Three-dimensional characterization of bacterial microcolonies on solid agar-based culture media.

    PubMed

    Drazek, Laurent; Tournoud, Maud; Derepas, Frédéric; Guicherd, Maryse; Mahé, Pierre; Pinston, Frédéric; Veyrieras, Jean-Baptiste; Chatellier, Sonia

    2015-02-01

    For the last century, in vitro diagnostic process in microbiology has mainly relied on the growth of bacteria on the surface of a solid agar medium. Nevertheless, few studies focused in the past on the dynamics of microcolonies growth on agar surface before 8 to 10h of incubation. In this article, chromatic confocal microscopy has been applied to characterize the early development of a bacterial colony. This technology relies on a differential focusing depth of the white light. It allows one to fully measure the tridimensional shape of microcolonies more quickly than classical confocal microscopy but with the same spatial resolution. Placing the device in an incubator, the method was able to individually track colonies growing on an agar plate, and to follow the evolution of their surface or volume. Using an appropriate statistical modeling framework, for a given microorganism, the doubling time has been estimated for each individual colony, as well as its variability between colonies, both within and between agar plates. A proof of concept led on four bacterial strains of four distinct species demonstrated the feasibility and the interest of the approach. It showed in particular that doubling times derived from early tri-dimensional measurements on microcolonies differed from classical measurements in micro-dilutions based on optical diffusion. Such a precise characterization of the tri-dimensional shape of microcolonies in their late-lag to early-exponential phase could be beneficial in terms of in vitro diagnostics. Indeed, real-time monitoring of the biomass available in a colony could allow to run well established microbial identification workflows like, for instance, MALDI-TOF mass-spectrometry, as soon as a sufficient quantity of material is available, thereby reducing the time needed to provide a diagnostic. Moreover, as done for pre-identification of macro-colonies, morphological indicators such as three-dimensional growth profiles derived from

  13. Angioid streaks - a rare cause of neovascular glaucoma. Case report.

    PubMed

    Ungureanu, E; Geamanu, A; Careba, I; Grecescu, M; Gradinaru, S

    2014-01-01

    Rationale. Neovascular glaucoma is the type of glaucoma most refractory to treatment. The most frequent causes are those associated with retinal hypoxia, such as proliferative diabetic retinopathy, central retinal vein occlusion, branch retinal vein occlusion, central retinal arterial occlusion, ischemic ocular syndrome etc. Rare causes of neovascular glaucoma are multiple and are due to VEGF synthesis associated with chorioretinal inflammations or degenerations. We present a case with neovascular glaucoma associated with an extremely rare cause, angioid streaks Objective. The objective of our prsentation was to asses efficacy of the 5-FU associated trabeculectomy following bevacizumab intravitreal administration Methods and results. Case report of a 48 years old female patient which presented at the emergency room with painful red left eye. At presentation best corrected left eye visual acuity was 1/10, intraocular pressure was 36 mm Hg. Examination established the diagnosis of Neovascular glaucoma associated with angioid streaks. After intravenous Manitol, oral Acetazolamide and topical treatment with fixed combination timolol-brinzolamide, topical steroid and mydriatic intraocular pressure decreased. Intravitreal bevacizumab injection was performed, followed after 3 weeks by trabeculectomy. Discussion. Angioid streaks are an extremely rare cause of neovascular glaucoma. The treatment is similar to the treatment for other causes of neovascular glaucoma. PMID:27057253

  14. Automatic coil selection for streak artifact reduction in radial MRI.

    PubMed

    Xue, Yiqun; Yu, Jiangsheng; Kang, Hyun Seon; Englander, Sarah; Rosen, Mark A; Song, Hee Kwon

    2012-02-01

    In radial MR imaging, streaking artifacts contaminating the entire field of view can arise from regions at the outer edges of the prescribed field of view. This can occur even when the Nyquist criterion is satisfied within the desired field of view. These artifacts become exacerbated when parts of the object lie in the superior/inferior regions of the scanner where the gradient strengths become weakened. When multiple coil arrays are used for signal reception, coils at the outer edges can be disabled before data acquisition to reduce the artifact levels. However, as the weakened gradient strengths near the edges often distort the object, causing the signal to become highly concentrated into a small region, the streaks are often not completely removed. Data from certain coils can also be excluded during reconstruction by visually inspecting the individual coil images, but this is impractical for routine use. In this work, a postprocessing method is proposed to automatically identify those coils whose images contain high levels of streaking for subsequent exclusion during reconstruction. The proposed method was demonstrated in vivo dynamic contrast enhanced MRI datasets acquired using a three-dimensional hybrid radial sequence. The results demonstrate that the proposed strategy substantially improves the image quality and show excellent agreement with images reconstructed with manually determined coil selection. PMID:21656562

  15. Streak artifact reduction in cardiac cone beam CT

    NASA Astrophysics Data System (ADS)

    Shechter, Gilad; Naveh, Galit; Lessick, Jonathan; Altman, Ami

    2005-04-01

    Cone beam reconstructed cardiac CT images suffer from characteristic streak artifacts that affect the quality of coronary artery imaging. These artifacts arise from inhomogeneous distribution of noise. While in non-tagged reconstruction inhomogeneity of noise distribution is mainly due to anisotropy of the attenuation of the scanned object (e.g. shoulders), in cardiac imaging it is largely influenced by the non-uniform distribution of the acquired data used for reconstructing the heart at a given phase. We use a cardiac adaptive filter to reduce these streaks. In difference to previous methods of adaptive filtering that locally smooth data points on the basis of their attenuation values, our filter is applied as a function of the noise distribution of the data as it is used in the phase selective reconstruction. We have reconstructed trans-axial images without adaptive filtering, with a regular adaptive filter and with the cardiac adaptive filter. With the cardiac adaptive filter significant reduction of streaks is achieved, and thus image quality is improved. The coronary vessel is much more pronounced in the cardiac adaptive filtered images, in slab MIP the main coronary artery branches are more visible, and non-calcified plaque is better differentiated from vessel wall. This improvement is accomplished without altering significantly the border definition of calcified plaques.

  16. Angioid streaks - a rare cause of neovascular glaucoma. Case report.

    PubMed Central

    Ungureanu, E; Geamanu, A; Careba, I; Grecescu, M; Gradinaru, S

    2014-01-01

    Rationale. Neovascular glaucoma is the type of glaucoma most refractory to treatment. The most frequent causes are those associated with retinal hypoxia, such as proliferative diabetic retinopathy, central retinal vein occlusion, branch retinal vein occlusion, central retinal arterial occlusion, ischemic ocular syndrome etc. Rare causes of neovascular glaucoma are multiple and are due to VEGF synthesis associated with chorioretinal inflammations or degenerations. We present a case with neovascular glaucoma associated with an extremely rare cause, angioid streaks Objective. The objective of our prsentation was to asses efficacy of the 5-FU associated trabeculectomy following bevacizumab intravitreal administration Methods and results. Case report of a 48 years old female patient which presented at the emergency room with painful red left eye. At presentation best corrected left eye visual acuity was 1/10, intraocular pressure was 36 mm Hg. Examination established the diagnosis of Neovascular glaucoma associated with angioid streaks. After intravenous Manitol, oral Acetazolamide and topical treatment with fixed combination timolol-brinzolamide, topical steroid and mydriatic intraocular pressure decreased. Intravitreal bevacizumab injection was performed, followed after 3 weeks by trabeculectomy. Discussion. Angioid streaks are an extremely rare cause of neovascular glaucoma. The treatment is similar to the treatment for other causes of neovascular glaucoma PMID:27057253

  17. Infrared imagery of streak formation in a breaking wave

    NASA Astrophysics Data System (ADS)

    Handler, Robert A.; Savelyev, Ivan; Lindsey, Michael

    2012-12-01

    High resolution infrared imagery of breaking waves in a wave-tank free of wind shear or current reveals the production of a "streaky," quasi-periodic thermal pattern produced during the breaking process. The streaks, or elongated patterns of warm and cold fluid, are found to form only when surface turbulence is present before wave breaking occurs. This suggests that wave-turbulence interaction is one mechanism that can lead to streak formation in breaking wave systems. More specifically, the streaky structures observed in these experiments may be caused by an intense, rapid tilting, and stretching of pre-existing vertical vorticity by the Stokes drift generated at or near the breaking wave crests, thereby generating a coherent system of counter-rotating vortices. We attempt to relate our observations to the recent theory of Teixeira and Belcher [J. Fluid Mech. 458, 229-267 (2002), 10.1017/S0022112002007838]. Some properties of the streaks, such as the dependence of their lifetimes and spanwise scale on wave amplitude, are presented.

  18. Design of microcontroller based system for automation of streak camera

    SciTech Connect

    Joshi, M. J.; Upadhyay, J.; Deshpande, P. P.; Sharma, M. L.; Navathe, C. P.

    2010-08-15

    A microcontroller based system has been developed for automation of the S-20 optical streak camera, which is used as a diagnostic tool to measure ultrafast light phenomenon. An 8 bit MCS family microcontroller is employed to generate all control signals for the streak camera. All biasing voltages required for various electrodes of the tubes are generated using dc-to-dc converters. A high voltage ramp signal is generated through a step generator unit followed by an integrator circuit and is applied to the camera's deflecting plates. The slope of the ramp can be changed by varying values of the capacitor and inductor. A programmable digital delay generator has been developed for synchronization of ramp signal with the optical signal. An independent hardwired interlock circuit has been developed for machine safety. A LABVIEW based graphical user interface has been developed which enables the user to program the settings of the camera and capture the image. The image is displayed with intensity profiles along horizontal and vertical axes. The streak camera was calibrated using nanosecond and femtosecond lasers.

  19. Resolution limitations and optimization of the LLNL streak camera focus

    SciTech Connect

    Lerche, R.A.; Griffith, R.L.

    1987-09-01

    The RCA C73435 image tube is biased at voltages far from its original design in the LLNL ultrafast (10 ps) streak camera. Its output resolution at streak camera operating potentials has been measured as a function of input slit width, incident-light wavelength, and focus-grid voltage. The temporal resolution is insensitive to focus-grid voltage for a narrow (100 ..mu..m) input slit, but is very sensitive to focus-grid voltage for a wide (2 mm) input slit. At the optimum wide-slit focus voltage, temporal resolution is insensitive to slit width. Spatial resolution is nearly independent of focus-grid voltage for values that give good temporal resolution. Both temporal and spatial resolution depend on the incident-light wavelength. Data for 1.06-..mu..m light show significantly better focusing than for 0.53-..mu..m light. Streak camera operation is simulated with a computer program that calculates photoelectron trajectories. Electron ray tracing describes all of the observed effects of slit width, incident-light wavelength, and focus-grid voltage on output resolution. 7 refs.

  20. Slope streaks on Mars: A new “wet” mechanism

    NASA Astrophysics Data System (ADS)

    Kreslavsky, Mikhail A.; Head, James W.

    2009-06-01

    Slope steaks are one of the most intriguing modern phenomena observed on Mars. They have been mostly interpreted as some specific type of granular flow. We propose another mechanism for slope streak formation on Mars. It involves natural seasonal formation of a modest amount of highly concentrated chloride brines within a seasonal thermal skin, and runaway propagation of percolation fronts. Given the current state of knowledge of temperature regimes and the composition and structure of the surface layer in the slope streak regions, this mechanism is consistent with the observational constraints; it requires an assumption that a significant part of the observed chlorine to be in form of calcium and ferric chloride, and a small part of the observed hydrogen to be in form of water ice. This "wet" mechanism has a number of appealing advantages in comparison to the widely accepted "dry" granular flow mechanism. Potential tests for the "wet" mechanism include better modeling of the temperature regime and observations of the seasonality of streak formation.

  1. Design of microcontroller based system for automation of streak camera

    NASA Astrophysics Data System (ADS)

    Joshi, M. J.; Upadhyay, J.; Deshpande, P. P.; Sharma, M. L.; Navathe, C. P.

    2010-08-01

    A microcontroller based system has been developed for automation of the S-20 optical streak camera, which is used as a diagnostic tool to measure ultrafast light phenomenon. An 8 bit MCS family microcontroller is employed to generate all control signals for the streak camera. All biasing voltages required for various electrodes of the tubes are generated using dc-to-dc converters. A high voltage ramp signal is generated through a step generator unit followed by an integrator circuit and is applied to the camera's deflecting plates. The slope of the ramp can be changed by varying values of the capacitor and inductor. A programmable digital delay generator has been developed for synchronization of ramp signal with the optical signal. An independent hardwired interlock circuit has been developed for machine safety. A LABVIEW based graphical user interface has been developed which enables the user to program the settings of the camera and capture the image. The image is displayed with intensity profiles along horizontal and vertical axes. The streak camera was calibrated using nanosecond and femtosecond lasers.

  2. Stabilization of boundary layer streaks by plasma actuators

    NASA Astrophysics Data System (ADS)

    Riherd, Mark; Roy, Subrata

    2014-03-01

    A flow's transition from laminar to turbulent leads to increased levels of skin friction. In recent years, dielectric barrier discharge actuators have been shown to be able to delay the onset of turbulence in boundary layers. While the laminar to turbulent transition process can be initiated by several different instability mechanisms, so far, only stabilization of the Tollmien-Schlichting path to transition has received significant attention, leaving the stabilization of other transition paths using these actuators less explored. To fill that void, a bi-global stability analysis is used here to examine the stabilization of boundary layer streaks in a laminar boundary layer. These streaks, which are important to both transient and by-pass instability mechanisms, are damped by the addition of a flow-wise oriented plasma body force to the boundary layer. Depending on the magnitude of the plasma actuation, this damping can be up to 25% of the perturbation's kinetic energy. The damping mechanism appears to be due to highly localized effects in the immediate vicinity of the body force, and when examined using a linearized Reynolds-averaged Navier-Stokes energy balance, indicate negative production of the perturbation's kinetic energy. Parametric studies of the stabilization have also been performed, varying the magnitude of the plasma actuator's body force and the spanwise wavenumber of the actuation. Based on these parametric studies, the damping of the boundary layer streaks appears to be linear with respect to the total amount of body force applied to the flow.

  3. Dilution, Concentration, and Flotation

    ERIC Educational Resources Information Center

    Liang, Ling; Schmuckler, Joseph S.

    2004-01-01

    As both classroom teaching practice and literature show, many students have difficulties learning science concepts such as density. Here are some investigations that identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution.…

  4. Helium dilution refrigeration system

    DOEpatents

    Roach, P.R.; Gray, K.E.

    1988-09-13

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

  5. Helium dilution refrigeration system

    DOEpatents

    Roach, Patrick R.; Gray, Kenneth E.

    1988-01-01

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

  6. Analysis of extraembryonic mesodermal structure formation in the absence of morphological primitive streak.

    PubMed

    Jin, Jiu-Zhen; Zhu, Yuanqi; Warner, Dennis; Ding, Jixiang

    2016-08-01

    During mouse gastrulation, the primitive streak is formed on the posterior side of the embryo. Cells migrate out of the primitive streak to form the future mesoderm and endoderm. Fate mapping studies revealed a group of cell migrate through the proximal end of the primitive streak and give rise to the extraembryonic mesoderm tissues such as the yolk sac blood islands and allantois. However, it is not clear whether the formation of a morphological primitive streak is required for the development of these extraembryonic mesodermal tissues. Loss of the Cripto gene in mice dramatically reduces, but does not completely abolish, Nodal activity leading to the absence of a morphological primitive streak. However, embryonic erythrocytes are still formed and assembled into the blood islands. In addition, Cripto mutant embryos form allantoic buds. However, Drap1 mutant embryos have excessive Nodal activity in the epiblast cells before gastrulation and form an expanded primitive streak, but no yolk sac blood islands or allantoic bud formation. Lefty2 embryos also have elevated levels of Nodal activity in the primitive streak during gastrulation, and undergo normal blood island and allantois formation. We therefore speculate that low level of Nodal activity disrupts the formation of morphological primitive streak on the posterior side, but still allows the formation of primitive streak cells on the proximal side, which give rise to the extraembryonic mesodermal tissues formation. Excessive Nodal activity in the epiblast at pre-gastrulation stage, but not in the primitive streak cells during gastrulation, disrupts extraembryonic mesoderm development. PMID:27273137

  7. Effect of BiTek agar on lysostaphin susceptibility of staphylococci.

    PubMed Central

    Langlois, B E; Dawson, K; Akers, K

    1990-01-01

    Staphylococci which were considered to be lysostaphin susceptible on P agar containing Bacto-Agar showed different degrees of resistance to lysostaphin when tested on P agar made with BiTek agar. As a result, lysostaphin-susceptible strains were misidentified as lysostaphin-resistant strains. Images PMID:2254432

  8. Growth kinetics of three species of Tetrahymena on solid agar

    SciTech Connect

    Dobra, K.W.; McArdle, E.W.; Ehret, C.F.

    1980-01-01

    A nutrient-agar method without liquid overlay has been developed for cultivation of ciliates. Three species of Tetrahymena-T. pyriformis strain W, T. rostrata strain UNI, and T. vorax strain V/sub 2/S, representing the 3 main groups of Tetrahymena species, were used; however the method should apply to other ciliates. Growth on the surface of the agar was facilitated by an optimal surface-to-volume ratio yielding a high density of ciliates and short generation times. At the highest density achieved, the cells became irregularly hexagonal and formed a monolayer tissue on the agar. Ciliates grown on agar were like those in liquid culture, typical oral ciliature, food-vacuole formation, and typical cortical patterns being retained. Advantages of this method include high cell density, easy recovery, and optimal O/sub 2/ supply. The organisms can also be cultivated on the surface of sterile cellulose-nitrate filters, facilitating in situ fixation and staining as well as transfer into different media by transfer of filters with cells, without prior centrifugation and resuspension.

  9. Hyperspectral Imaging for Detecting Pathogens Grown on Agar Plates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper is concerned with the development of a hyperspectral imaging technique for detecting and identifying one of the most common foodborne pathogens, Campylobacter. Direct plating using agars is an effective tool for laboratory tests and analyses of microorganisms. The morphology (size, growth...

  10. Recovery of Sublethally Injured Bacteria Using Selective Agar Overlays.

    ERIC Educational Resources Information Center

    McKillip, John L.

    2001-01-01

    This experiment subjects bacteria in a food sample and an environmental sample to conditions of sublethal stress in order to assess the effectiveness of the agar overlay method to recover sublethally injured cells compared to direct plating onto the appropriate selective medium. (SAH)

  11. 21 CFR 866.4600 - Ouchterlony agar plate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ouchterlony agar plate. 866.4600 Section 866.4600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  12. 21 CFR 866.4600 - Ouchterlony agar plate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ouchterlony agar plate. 866.4600 Section 866.4600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  13. 21 CFR 866.4600 - Ouchterlony agar plate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ouchterlony agar plate. 866.4600 Section 866.4600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  14. 21 CFR 866.4600 - Ouchterlony agar plate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ouchterlony agar plate. 866.4600 Section 866.4600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  15. 21 CFR 866.4600 - Ouchterlony agar plate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ouchterlony agar plate. 866.4600 Section 866.4600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  16. Improving agar electrospinnability with choline-based deep eutectic solvents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One percent agar (% wt) was dissolved in the deep eutectic solvent (DES), (2-hydroxyethyl) trimethylammonium chloride/urea at a 1:2 molar ratio, and successfully electrospun into nanofibers. An existing electrospinning set-up, operated at 50 deg C, was adapted for use with an ethanol bath to collect...

  17. On the nature and visibility of crater-associated streaks on Mars

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Thomas, P.; Sagan, C.

    1978-01-01

    The paper considers Mariner 9 and Viking data that contradict Kuzmin's (1975) hypothesis that all crater-associated wind streaks on Mars are depositional and consist of unresolved barchan-like dunes. According to Kuzmin's hypothesis, any streak can appear either bright or dark relative to its surroundings depending on the sun's position. The spacecraft images, however, show examples of dark and light streaks visible at the same azimuth angle of the sun. Evidence that bright and dark streaks differ both in morphology and in character is considered. It is suggested that the common ragged dark streaks are probably erosion scars while most bright streaks probably represent accumulations of bright dust-storm fallout.

  18. Hot streaks and phantom cooling in a turbine rotor passage. II - Combined effects and analytical modelling

    NASA Technical Reports Server (NTRS)

    Roback, Richard J.; Dring, Robert P.

    1992-01-01

    Experimental documentation and analytical correlations demonstrating the effects of hot streak accumulation and phantom cooling on turbine rotor airfoil surface temperature are presented. Results are shown which quantify the impact of a nonuniform temperature profile at the entrance of a turbine due to combustor-generated hot and cold streaks, and cooling air discharged from the trailing edge of the upstream stator. Experimental results are shown for a range of controlling variables to identify where streak accumulation and phantom cooling were most likely to be strongest. These variables include streak-to-free stream density ratio, streak injection location, and coolant-to-free stream density and velocity ratios. Experimental results are shown for the combined effects of hot streak and stator coolant on the adiabatic recovery temperature of the rotor.

  19. Development of a selective agar plate for the detection of Campylobacter spp. in fresh produce.

    PubMed

    Yoo, Jin-Hee; Choi, Na-Young; Bae, Young-Min; Lee, Jung-Su; Lee, Sun-Young

    2014-10-17

    This study was conducted to develop a selective medium for the detection of Campylobacter spp. in fresh produce. Campylobacter spp. (n=4), non-Campylobacter (showing positive results on Campylobacter selective agar) strains (n=49) isolated from fresh produce, indicator bacteria (n=13), and spoilage bacteria isolated from fresh produce (n=15) were plated on four Campylobacter selective media. Bolton agar and modified charcoal cefoperazone deoxycholate agar (mCCDA) exhibited higher sensitivity for Campylobacter spp. than did Preston agar and Hunt agar, although certain non-Campylobacter strains isolated from fresh produce by using a selective agar isolation method, were still able to grow on Bolton agar and mCCDA. To inhibit the growth of non-Campylobacter strains, Bolton agar and mCCDA were supplemented with 5 antibiotics (rifampicin, polymyxin B, sodium metabisulfite, sodium pyruvate, ferrous sulfate) and the growth of Campylobacter spp. (n=7) and non-Campylobacter strains (n=44) was evaluated. Although Bolton agar supplemented with rifampicin (BR agar) exhibited a higher selectivity for Campylobacter spp. than did mCCDA supplemented with antibiotics, certain non-Campylobacter strains were still able to grow on BR agar (18.8%). When BR agar with various concentrations of sulfamethoxazole-trimethoprim were tested with Campylobacter spp. (n=8) and non-Campylobacter (n=7), sulfamethoxazole-trimethoprim was inhibitory against 3 of 7 non-Campylobacter strains. Finally, we validated the use of BR agar containing 50mg/L sulfamethoxazole (BRS agar) or 0.5mg/L ciprofloxacin (BRCS agar) and other selective agars for the detection of Campylobacter spp. in chicken and fresh produce. All chicken samples were positive for Campylobacter spp. when tested on mCCDA, BR agar, and BRS agar. In fresh produce samples, BRS agar exhibited the highest selectivity for Campylobacter spp., demonstrating its suitability for the detection of Campylobacter spp. in fresh produce. PMID:25126968

  20. Thermal-induced ageing of agar solutions: impact on the structural and mechanical properties of agar gels

    NASA Astrophysics Data System (ADS)

    Mao, Bosi; Bentaleb, Ahmed; Louerat, Frédéric; Divoux, Thibaut; Snabre, Patrick

    Numerous hydrogels are prepared by cooling down to ambient temperature, aqueous polymer solutions brought to a boil. Although the incubation time of the polymer solution at such a high temperature could be used as a tuning parameter, its impact on the subsequent gelation has been poorly investigated. Here we study the effect of prolonged heating at 80°C on a 1.5% wt solution of agar, a natural polysaccharide. The incubation time is varied from a few hours up to five days. We show that the agar sol. continuously degrades as the result of both the hydrolysis and the intermolecular oxidation of the polymer chains. Furthermore, electronic microscopy and X-ray diffraction experiments reveal that gels formed from older agar sols display an increasingly coarser microstructure composed of micron-sized aggregated pieces of polysaccharides, in contrast with the fibrous-like structure of gels made from fresh sols. Along with structural changes prolonged incubation time leads to weaker gels of lower shear elastic modulus. Finally, macro-indentation experiments coupled to direct visualization show that increasing the incubation time of the agar sol. decreases the yield strain of the gel by a factor of three, while the rupture scenario turns continuously from brittle to ductile-like. Acknowledging funding from BioMérieux & CNRS.

  1. Total Antioxidant Capacity of Serum Determined Using the Potassium Permanganate Agar Method Based on Serum Diffusion in Agar.

    PubMed

    Zhou, Ying; Zhang, Meijuan; Liu, Hui

    2015-01-01

    Objectives. To develop a new method for determining total antioxidants in serum and to evaluate the total antioxidant capacity of organisms. Design and Methods. Sodium hyposulfite (Na2S2O3) and serum were used to evaluate the linearity and precision of the potassium permanganate agar method. The area of serum diffusion in samples from 30 intensive care unit (ICU) patients compared with 44 healthy subjects was determined by the potassium permanganate agar method. Results. The linearity (R (2) in the linear experiment of Na2S2O3 was 0.994; R (2) in the linear experiment of serum was 0.987) and precision (coefficient of variation of area of high level serum diffusion within-run, between-run, and between-day and coefficient of variation of area of low serum diffusion within-run, between-run, and between-day were all less than 10%) were acceptable using the potassium permanganate agar method. Total antioxidants of serum between the ICU group and the healthy group were different (p = 0.002, two tailed). Conclusions. Total antioxidants in serum can be determined by the potassium permanganate agar method. The total antioxidant capacity of an organism can be evaluated by the amount of total antioxidants in serum. PMID:26347595

  2. Total Antioxidant Capacity of Serum Determined Using the Potassium Permanganate Agar Method Based on Serum Diffusion in Agar

    PubMed Central

    Zhou, Ying; Zhang, Meijuan; Liu, Hui

    2015-01-01

    Objectives. To develop a new method for determining total antioxidants in serum and to evaluate the total antioxidant capacity of organisms. Design and Methods. Sodium hyposulfite (Na2S2O3) and serum were used to evaluate the linearity and precision of the potassium permanganate agar method. The area of serum diffusion in samples from 30 intensive care unit (ICU) patients compared with 44 healthy subjects was determined by the potassium permanganate agar method. Results. The linearity (R2 in the linear experiment of Na2S2O3 was 0.994; R2 in the linear experiment of serum was 0.987) and precision (coefficient of variation of area of high level serum diffusion within-run, between-run, and between-day and coefficient of variation of area of low serum diffusion within-run, between-run, and between-day were all less than 10%) were acceptable using the potassium permanganate agar method. Total antioxidants of serum between the ICU group and the healthy group were different (p = 0.002, two tailed). Conclusions. Total antioxidants in serum can be determined by the potassium permanganate agar method. The total antioxidant capacity of an organism can be evaluated by the amount of total antioxidants in serum. PMID:26347595

  3. Agar-agar entrapment increases the stability of endo-β-1,4-xylanase for repeated biodegradation of xylan.

    PubMed

    Bibi, Zainab; Shahid, Faiza; Ul Qader, Shah Ali; Aman, Afsheen

    2015-04-01

    Microbial xylanases, specially endo-β-1,4-xylanase catalyzes the hydrolysis of xylan, is considered one of the most significant hydrolases. It has numerous applications but most extensively is utilized in paper and pulp industry as a bio-bleaching agent. Immobilization technique is comprehensively studied with the expectation of modifying and improving enzyme stability and characteristics for commercial purposes. Currently, matrix entrapment technique is applied to immobilize endo-β-1,4-xylanase within agar-agar gel beads produced by Geobacillus stearothermophilus KIBGE-IB29. Maximal enzyme immobilization yield was achieved at 2.5% of agar-agar concentration. Optimized conditions demonstrated an increase in the optimal reaction time from 05 min to 30 min and incubation temperature from 50 °C to 60 °C with reference to free enzyme whereas; no effect was observed for optimum pH. Entrapment technique uniquely changed the kinetic parameters of immobilized endo-β-1,4-xylanase (Km: 0.5074 mg min(-1) to 0.5230 mg min(-1) and Vmax: 4773 U min(-1) to 968 U min(-1)) as compared to free enzyme. However, immobilized enzyme displayed broad thermal stability and retained 79.0% of its initial activity at 80 °C up to 30 min whereas; free enzyme completely lost its activity at this temperature. With respect to economic feasibility, the immobilized enzyme showed impressive recycling efficiency up to six reaction cycles. PMID:25603143

  4. Complete genome sequence of a novel badnavirus, banana streak IM virus.

    PubMed

    Geering, Andrew D W; Parry, Judith N; Thomas, John E

    2011-04-01

    In 1999, banana streak disease outbreaks occurred at two locations in Australia in new banana hybrids that were being screened for fusarium wilt resistance. Two different badnaviruses, banana streak GF virus and a newly discovered virus called banana streak IM virus (BSIMV), were detected in these plants. The complete nucleotide sequence of the BSIMV genome was determined and comprised 7768 nt. Three open reading frames were detected, the first beginning with a non-conventional start codon (CUG). A 55-nt repetition in the putative pregenomic RNA promoter was also identified. Phylogenetic analysis suggests that BSIMV is most closely related to banana streak VN virus. PMID:21347843

  5. Surface properties of the Pettit wind streak on Mars Implications for sediment transport

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.

    1986-04-01

    Satellite imagery of the Pettit streak on Amazonis Planitia are discussed in terms of the details of wind streaks and their associated sediments. Increasingly more detailed blow-ups of the available imagery demonstrate that the Pettit streak holds both a Type I bright streak (at the crater rim) and a Type II dark streak beginning at the dark patch within the crater. The lowest albedos measured, 0.20-0.22, are associated with the highest thermal inertia, indicative of grain diameters similar to medium sand, i.e., ranging from 250-350 microns. The brightest portions of the streak have albedos over 0.26 and a low thermal inertia, in the range 3-4, which implies the presence of fine-grained sand, diameters from 50-100 microns. The particle grains are less than 50 microns diameter in the surrounding plains, which have an approximately uniform albedo (0.27) and a thermal inertia of 2.5, characteristics typical of silt or clay. Current streak models describe the dark streak well, but do not account for the bright streak, which may be optically thick patches of very fine dust.

  6. Defrosting Polar Dunes--Dark Spots and Wind Streaks

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The first time that the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)team saw dark spots on defrosting dune surfaces was in August and September of 1998. At that time, it was the north polar seasonal frost cap that was subliming away (more recent images from 1999 have shown the south polar frosts). This picture (above) shows a small portion of the giant dune field that surrounds the north polar region, as it appeared on August 23, 1998. At the time, it was early northern spring and the dunes were still covered with winter frost.

    Dark spots had appeared on the north polar dunes, and many of them exhibited a radial or semi-radial pattern of dark streaks and streamers. At first, there was speculation that the streaks indicated that the defrosting process might somehow involve explosions! The dark spots seemed to resemble small craters with dark, radial ejecta. It seemed possible that frozen carbon dioxide trapped beneath water ice might somehow heat up, turn to gas, expand, and then 'explode' in either a small blast or at least a 'puff' of air similar to that which comes from the blowhole of a surfacing whale or seal.

    The image shown here changed the earlier impression. The dark spots and streaks do not result from explosions. The spots--though not well understood--represent the earliest stages of defrosting on the sand dunes. The streaks, instead of being caused by small explosions, are instead the result of wind. In this picture, the fine, dark streaks show essentially identical orientations from spot to spot (e.g., compare the spots seen in boxes (a) and (b)). Each ray of dark material must result from wind blowing from a particular direction--for example, all of the spots in this picture exhibit a ray that points toward the upper left corner of the image, and each of these rays indicates the same wind regime. Each spot also has a ray pointing toward the lower right and top/upper-right. These, too, must indicate periods when the wind was strong

  7. Comparison of the BBL CHROMagar Staph aureus Agar Medium to Conventional Media for Detection of Staphylococcus aureus in Respiratory Samples

    PubMed Central

    Flayhart, Diane; Lema, Clara; Borek, Anita; Carroll, Karen C.

    2004-01-01

    Screening for Staphylococcus aureus has become routine in certain patient populations. This study is the first clinical evaluation of the BBL CHROMagar Staph aureus agar (CSA) medium (BD Diagnostics, Sparks, Md.) for detection of S. aureus in nasal surveillance cultures and in respiratory samples from cystic fibrosis (CF) patients. S. aureus colonies appear mauve on CSA. Other organisms are inhibited or produce a distinctly different colony color. S. aureus was identified from all media by slide coagulase, exogenous DNase, and mannitol fermentation assays. Susceptibility testing was performed using the agar dilution method. A total of 679 samples were evaluated. All samples were inoculated onto CSA. Nasal surveillance cultures were inoculated onto sheep blood agar (SBA) (BD Diagnostics), and samples from CF patients were inoculated onto mannitol salt agar (MSA) (BD Diagnostics). Of the 679 samples cultured, 200 organisms produced a mauve color on CSA (suspicious for S. aureus) and 180 were positive for S. aureus on SBA or MSA. Of 200 CSA-positive samples 191 were identified as S. aureus. Nine mauve colonies were slide coagulase negative and were subsequently identified as Staphylococcus lugdunensis (one), Staphylococcus epidermidis (three), Staphylococcus haemolyticus (one), and Corynebacterium species (four). CSA improved the ability to detect S. aureus by recovering 12 S. aureus isolates missed by conventional media. Of the 192 S. aureus isolates recovered, 122 were methicillin susceptible and 70 were methicillin resistant. Overall, the sensitivity and specificity of CSA in this study were 99.5 and 98%, respectively. There was no difference in the performance of the slide coagulase test or in susceptibility testing performed on S. aureus recovered from CSA compared to SBA or MSA. Our data support the use of CSA in place of standard culture media for detection of S. aureus in heavily contaminated respiratory samples. PMID:15297498

  8. Characterization of Brown Streak Virus-Resistant Cassava.

    PubMed

    Anjanappa, Ravi B; Mehta, Devang; Maruthi, M N; Kanju, Edward; Gruissem, Wilhelm; Vanderschuren, Hervé

    2016-07-01

    Cassava brown streak disease (CBSD) has become a major constraint to cassava production in East and Central Africa. The identification of new sources of CBSD resistance is essential to deploy CBSD mitigation strategies, as the disease is progressing westwards to new geographical areas. A stringent infection method based on top cleft-grafting combined with precise virus titer quantitation was utilized to screen 14 cassava cultivars and elite breeding lines. When inoculated with mixed infections of Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), the scions of elite breeding lines KBH 2006/18 and KBH 2006/26 remained symptom-free during a 16-week period of virus graft inoculation, while susceptible varieties displayed typical CBSD infection symptoms at 4 weeks after grafting. The identified CBSD resistance was stable under the coinoculation of CBSV and UCBSV with cassava geminiviruses. Double-grafting experiments revealed that transmission of CBSV and UCBSV to CBSD-susceptible top scions was delayed when using intermediate scions of elite breeding lines KBH 2006/18 and KBH 2006/26. Nonetheless, comparison of virus systemic movement using scions from KBH2006/18 and a transgenic CBSD resistant 60444 line (60444-Hp9 line) showed that both CBSV and UCBSV move at undetectable levels through the stems. Further, protoplast-based assays of virus titers showed that the replication of CBSV is inhibited in the resistant line KBH2006/18, suggesting that the identified CBSD resistance is at least partially based on inhibition of virus replication. Our molecular characterization of CBSD resistance in cassava offers a robust virus-host system to further investigate the molecular determinants of CBSD resistance. PMID:27070326

  9. Streaked radiography measurements of convergent ablator performance (invited)

    SciTech Connect

    Hicks, D. G.; Spears, B. K.; Braun, D. G.; Olson, R. E.; Sorce, C. M.; Celliers, P. M.; Collins, G. W.; Landen, O. L.

    2010-10-15

    The velocity and remaining ablator mass of an imploding capsule are critical metrics for assessing the progress toward ignition of an inertially confined fusion experiment. These and other ablator rocket parameters have been measured using a single streaked x-ray radiograph. A regularization technique has been used to determine the ablator density profile {rho}(r) at each time step; moments of {rho}(r) then provide the areal density, average radius, and mass of the unablated, or remaining, ablator material, with the velocity determined from the time derivative of the average radius. The technique has been implemented on experiments at the OMEGA laser facility.

  10. Comparison of chromogenic Biolog Rainbow agar Shigella/Aeromonas with xylose lysine desoxycholate agar for isolation and detection of Shigella spp. from foods.

    PubMed

    Zhang, Guodong; Lampel, Keith A

    2010-08-01

    Shigella outbreaks are widely reported throughout the world. However, it remains a challenge to isolate Shigella spp. from foods by using conventional microbiological media. The main objective of this study was to determine the effectiveness of a novel chromogenic medium, Rainbow agar Shigella/Aeromonas (Rainbow agar), for the isolation and detection of Shigella spp. in foods. All four Shigella species, S. sonnei, S. flexneri, S. dysenteriae, and S. boydii, were studied. Rainbow agar was compared with tryptic soy agar, xylose lysine desoxycholate agar (XLD), and Salmonella Shigella agar (SSA) for enumeration of Shigella spp. in pure culture. This chromogenic agar and XLD were also used to isolate Shigella spp. in artificially contaminated foods (4.8 log CFU/g of food), including lettuce, parsley, cilantro, spinach, potato salad, and shrimp. The inhibitory effect on Shigella growth by Rainbow agar was between that of XLD and SSA. All vegetables studied showed a moderately high background microflora on XLD and Rainbow agar. With artificially inoculated produce, Rainbow agar recovered about 1 to 2 log CFU more S. sonnei, S. dysenteriae, and S. boydii per g of food than did XLD. For potato salad and shrimp, which had low background microflora on Rainbow agar, Rainbow agar was slightly better in recovering Shigella spp. than XLD was in most cases. However, we found that the addition of streptomycin (6.25 mg/liter) to Rainbow agar could facilitate the isolation of Shigella in vegetables tested. In conclusion, Rainbow agar was a much more effective medium than was XLD for the isolation of Shigella spp. from foods. PMID:20819355

  11. Automatic diluter for bacteriological samples.

    PubMed

    Trinel, P A; Bleuze, P; Leroy, G; Moschetto, Y; Leclerc, H

    1983-02-01

    The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions. PMID:6338826

  12. Automatic diluter for bacteriological samples.

    PubMed Central

    Trinel, P A; Bleuze, P; Leroy, G; Moschetto, Y; Leclerc, H

    1983-01-01

    The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions. Images PMID:6338826

  13. Comparison of dosimetry gels prepared by agar and bovine gelatine

    NASA Astrophysics Data System (ADS)

    Sağsöz, M. E.; Korkut, Ö.; Alemdar, N.; Aktaş, S.; Çalı, E. B.; Kantarcı, M.

    2016-04-01

    Gel dosimeters are unique materials capable of showing three dimensional (3D) dose distributions of therapeutic or diagnostic exposures. Fricke gel dosimeters can be considered as chemical dosimeters that rely on a radiation-induced chemical reaction. Dose distribution of Fricke solutions containing Fe+2 ions determines the transformation of acidic, oxygen saturated Fe+2 ions to Fe+3 ions by the ionizing radiation in aqueous solutions. In this study we produced two different types of gel dosimeters using agar and bovine gelatin with similar fabrication methods. We compared the magnetic resonance (MR) T1 imaging responses of these two gel dosimeters to acquire a dose dependency of MR intensities. In conclusion agar gel dosimeters found to be produced easily and more consistent.

  14. A modified agar plate method for detection of Strongyloides stercoralis.

    PubMed

    Koga, K; Kasuya, S; Khamboonruang, C; Sukhavat, K; Ieda, M; Takatsuka, N; Kita, K; Ohtomo, H

    1991-10-01

    The agar plate method is a new technique with high detection rates for coprological diagnosis of human strongyloidiasis. This report details modifications of the technique and establishes a standardized procedure. We recommend that all plates should be carefully observed using a microscope because macroscopic observation can lead to false negative results. It is also advisable to pour formalin solution directly into microscopically positive dishes to collect worms by sedimentation. This procedure enables one to observe worms otherwise hidden. Sealing dishes with adhesive tape prevents larvae from crawling out of the dishes, eliminating any possibility in the reduction of detection rates, and greatly improves the safety conditions for the technician performing the procedure. We consider the agar plate method to be superior to the filter paper method in detecting Strongyloides, and we believe that it will eventually become the technique of choice. PMID:1951861

  15. Microprocessor-controlled, wide-range streak camera

    SciTech Connect

    Amy E. Lewis, Craig Hollabaugh

    2006-09-01

    Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera’s user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.

  16. Range accuracy analysis of streak tube imaging lidar systems

    NASA Astrophysics Data System (ADS)

    Ye, Guangchao; Fan, Rongwei; Chen, Zhaodong; Yuan, Wei; Chen, Deying; He, Ping

    2016-02-01

    Streak tube imaging lidar (STIL) is an active imaging system that has a high range accuracy and a wide range gate with the use of a pulsed laser transmitter and streak tube receiver to produce 3D range images. This work investigates the range accuracy performance of STIL systems based on a peak detection algorithm, taking into account the effects of blurring of the image. A theoretical model of the time-resolved signal distribution, including the static blurring width in addition to the laser pulse width, is presented, resulting in a modified range accuracy analysis. The model indicates that the static blurring width has a significant effect on the range accuracy, which is validated by both the simulation and experimental results. By using the optimal static blurring width, the range accuracies are enhanced in both indoor and outdoor experiments, with a stand-off distance of 10 m and 1700 m, respectively, and corresponding, best range errors of 0.06 m and 0.25 m were achieved in a daylight environment.

  17. [Further development of a streak retinoscope with calibrated collimator].

    PubMed

    Rohrschneider, K; Koch, H R

    1992-08-01

    Development and rationale of a new streak retinoscope have been discussed in an earlier paper. In contrast to classical retinoscopy this retinoscope determines the refraction by forming the narrowest streak in the test person's pupil with a calibrated collimator. In addition to the first prototype the extension of the lamp according to variation of the refraction is measured electronically and the data are transposed into a computer. This allows to freely choose a working distance in a range from about 30 to 120 cm and therefore it is possible to examine restless patients. Accuracy of the measurement was less than or equal to 0.25 D for Ametropia from -0.5 to 5.0 D in a working distance of 30 cm or from -4.0 to -1.5 D in 100 cm. In most persons it is not necessary to use additional glasses during refraction by choosing the adequate distance. Therefore this method can help to refract kids and other persons which could not be refracted by use of glasses. In addition this method excludes the accommodation of the patient as apposed to regular refractometers. PMID:1434382

  18. Mupirocin-mucin agar for selective enumeration of Bifidobacterium bifidum.

    PubMed

    Pechar, Radko; Rada, Vojtech; Parafati, Lucia; Musilova, Sarka; Bunesova, Vera; Vlkova, Eva; Killer, Jiri; Mrazek, Jakub; Kmet, Vladimir; Svejstil, Roman

    2014-11-17

    Bifidobacterium bifidum is a bacterial species exclusively found in the human intestinal tract. This species is becoming increasingly popular as a probiotic organism added to lyophilized products. In this study, porcine mucin was used as the sole carbon source for the selective enumeration of B. bifidum in probiotic food additives. Thirty-six bifidobacterial strains were cultivated in broth with mucin. Only 13 strains of B. bifidum utilized the mucin to produce acids. B. bifidum was selectively enumerated in eight probiotic food supplements using agar (MM agar) containing mupirocin (100 mg/L) and mucin (20 g/L) as the sole carbon source. MM agar was fully selective if the B. bifidum species was presented together with Bifidobacterium animalis subsp. lactis, Bifidobacterium breve, and Bifidobacterium longum subsp. longum species and with lactic acid bacteria (lactobacilli, streptococci). Isolated strains of B. bifidum were identified using biochemical, PCR, MALDI-TOF procedures and 16S rRNA gene sequencing. The novel selective medium was also suitable for the isolation of B. bifidum strains from human fecal samples. PMID:25217723

  19. Individual based simulations of bacterial growth on agar plates

    NASA Astrophysics Data System (ADS)

    Ginovart, M.; López, D.; Valls, J.; Silbert, M.

    2002-03-01

    The individual based simulator, INDividual DIScrete SIMulations (INDISIM) has been used to study the behaviour of the growth of bacterial colonies on a finite dish. The simulations reproduce the qualitative trends of pattern formation that appear during the growth of Bacillus subtilis on an agar plate under different initial conditions of nutrient peptone concentration, the amount of agar on the plate, and the temperature. The simulations are carried out by imposing closed boundary conditions on a square lattice divided into square spatial cells. The simulator studies the temporal evolution of the bacterial population possible by setting rules of behaviour for each bacterium, such as its uptake, metabolism and reproduction, as well as rules for the medium in which the bacterial cells grow, such as concentration of nutrient particles and their diffusion. The determining factors that characterize the structure of the bacterial colony patterns in the presents simulations, are the initial concentrations of nutrient particles, that mimic the amount of peptone in the experiments, and the set of values for the microscopic diffusion parameter related, in the experiments, to the amount of the agar medium.

  20. Modeling development of inhibition zones in an agar diffusion bioassay.

    PubMed

    Chandrasekar, Vaishnavi; Knabel, Stephen J; Anantheswaran, Ramaswamy C

    2015-09-01

    A two-temperature agar diffusion bioassay is commonly used to quantify the concentration of nisin using Micrococcus luteus as the indicator microorganism. A finite element computational model based on Fick's second law of diffusion was used to predict the radius of the inhibition zone in this diffusion bioassay. The model developed was used to calculate nisin concentration profiles as a function of time and position within the agar. The minimum inhibitory concentration (MIC) of nisin against M. luteus was determined experimentally. The critical time (T c) for growth of M. luteus within the agar diffusion bioassay was experimentally determined using incubation studies with nisin. The radius of the inhibition zone was predicted from the computational model as the location where the predicted nisin concentration at T c was equal to MIC. The MIC was experimentally determined to be 0.156 μg mL(-1), and T c was determined to be 7 h. Good agreement (R (2) = 0.984) was obtained between model-predicted and experimentally determined inhibition zone radii. PMID:26405525

  1. Modeling development of inhibition zones in an agar diffusion bioassay

    PubMed Central

    Chandrasekar, Vaishnavi; Knabel, Stephen J; Anantheswaran, Ramaswamy C

    2015-01-01

    A two-temperature agar diffusion bioassay is commonly used to quantify the concentration of nisin using Micrococcus luteus as the indicator microorganism. A finite element computational model based on Fick's second law of diffusion was used to predict the radius of the inhibition zone in this diffusion bioassay. The model developed was used to calculate nisin concentration profiles as a function of time and position within the agar. The minimum inhibitory concentration (MIC) of nisin against M. luteus was determined experimentally. The critical time (Tc) for growth of M. luteus within the agar diffusion bioassay was experimentally determined using incubation studies with nisin. The radius of the inhibition zone was predicted from the computational model as the location where the predicted nisin concentration at Tc was equal to MIC. The MIC was experimentally determined to be 0.156 μg mL−1, and Tc was determined to be 7 h. Good agreement (R2 = 0.984) was obtained between model-predicted and experimentally determined inhibition zone radii. PMID:26405525

  2. THEMIS-IR Emissivity Spectrum of a Large "Dark Streak" near Olympus Mons

    NASA Astrophysics Data System (ADS)

    Brumby, S. P.

    2004-03-01

    "Dark streaks" are unusual transient surface features found on Mars. We have obtained an infrared emissivity spectrum of a large dark streak on the north western edge of Olympus Mons, using imagery from the THEMIS instrument on the Mars Odyssey 2001 spacecraft.

  3. X-ray streak camera diagnostics of picosecond laser-plasma interactions

    SciTech Connect

    Cobble, J.A.; Fulton, R.D.; Jones, L.A.; Kyrala, G.A.; Schappert, G.T.; Taylor, A.J.; Wahlin, E.K.

    1992-05-01

    An x-ray streak camera is used to diagnose a laser-produced Al plasma with time resolution of {approximately}10 ps. A streak record of filtered emission and a time-integrated transmission grating spectrum reveal that the plasma radiation is dominated by emission from He- and H-like resonance lines. 11 refs.

  4. X-ray streak camera diagnostics of picosecond laser-plasma interactions

    SciTech Connect

    Cobble, J.A.; Fulton, R.D.; Jones, L.A.; Kyrala, G.A.; Schappert, G.T.; Taylor, A.J.; Wahlin, E.K.

    1992-01-01

    An x-ray streak camera is used to diagnose a laser-produced Al plasma with time resolution of {approximately}10 ps. A streak record of filtered emission and a time-integrated transmission grating spectrum reveal that the plasma radiation is dominated by emission from He- and H-like resonance lines. 11 refs.

  5. Averaging picosecond streak camera for time resolved x-ray and XUV spectroscopy of ultrashort plasmas

    NASA Astrophysics Data System (ADS)

    Maksimchuk, A.; Nantel, M.; Workman, J.; Umstadter, D.; Mourou, G.; Pikuz, S.

    1996-11-01

    We have developed an averaging picosecond x-ray streak camera that uses a DC-biased semi-insulating GaAs photoconductive switch as a generator of a high-voltage ramp for the deflection plates of the streak camera. The streak camera is operated at a sweep speed of up to 8 ps/mm, with a shot-to-shot jitter of 1 ps. The streak camera driven by this switch is absolutely synhronized with the femtosecond laser pulse and allows the direct accumulation of the x-ray temporal signals at a 10 Hz repetition rate. The streak camera has been used for the investigation of temporal behavior of keV x-ray lines and spectrally resolved XUV emission from solid target at the laser intensity of 10^17 W/cm^2. This work is supported by NSF under Grant STC PHY 8920108.

  6. Satellite Observations of Plume-like Streaks in a Cloud Field in Canada

    NASA Astrophysics Data System (ADS)

    Grasso, Lewis; Lindsey, Daniel T.; Seaman, Curtis J.; Stocks, Brian; Rabin, Robert M.

    2015-04-01

    On the afternoon of 28 October 2013, plume-like streaks were detected by geostationary and polar orbiting satellites over eastern Ontario, Canada. These streaks were characterized by enhanced reflectivity in the visible bands and warmer brightness temperatures at 3.9 µm. These streaks were part of a low-level liquid water cloud layer. Due to the similarity of the streaks to plume-like features in marine stratocumulus caused by smoke from the stacks of ships, so-called ship tracks, a local source of emitted aerosols was suspected and subsequently identified as the burning of logging residue. This event provides further support for the ability of locally enhanced aerosol loading to alter microphysical characteristics of clouds. Ship tracks, pollution plumes from industrial burning, and pyro-cumulus are known examples of this type of interaction. In addition, the plume-like streaks could be used indirectly to identify the location of the source of the emitted particles.

  7. Sub-picosecond streak camera measurements at LLNL: From IR to x-rays

    SciTech Connect

    Kuba, J; Shepherd, R; Booth, R; Steward, R; Lee, E W; Cross, R R; Springer, P T

    2003-12-21

    An ultra fast, sub-picosecond resolution streak camera has been recently developed at the LLNL. The camera is a versatile instrument with a wide operating wavelength range. The temporal resolution of up to 300 fs can be achieved, with routine operation at 500 fs. The streak camera has been operated in a wide wavelength range from IR to x-rays up to 2 keV. In this paper we briefly review the main design features that result in the unique properties of the streak camera and present its several scientific applications: (1) Streak camera characterization using a Michelson interferometer in visible range, (2) temporally resolved study of a transient x-ray laser at 14.7 nm, which enabled us to vary the x-ray laser pulse duration from {approx}2-6 ps by changing the pump laser parameters, and (3) an example of a time-resolved spectroscopy experiment with the streak camera.

  8. Betting Decision Under Break-Streak Pattern: Evidence from Casino Gaming.

    PubMed

    Fong, Lawrence Hoc Nang; So, Amy Siu Ian; Law, Rob

    2016-03-01

    Cognitive bias is prevalent among gamblers, especially those with gambling problems. Grounded in the heuristics theories, this study contributes to the literature by examining a cognitive bias triggered by the break streak pattern in the casino setting. We postulate that gamblers tend to bet on the latest outcome when there is a break-streak pattern. Moreover, three determinants of the betting decision under break-streak pattern, including the streak length of the alternative outcome, the frequency of the latest outcome, and gender, were identified and examined in this study. A non-participatory observational study was conducted among the Cussec gamblers in a casino in Macao. An analysis of 1229 bets confirms our postulation, particularly when the streak of the alternative outcome is long, the latest outcome is frequent, and the gamblers are females. The findings provide meaningful implications for casino management and public policymakers regarding the minimization of gambling harm. PMID:25967106

  9. Characterization of X-ray streak cameras for use on Nova

    SciTech Connect

    Kalantar, D.H.; Bell, P.M.; Costa, R.L.; Hammel, B.A.; Landen, O.L.; Orzechowski, T.J.; Hares, J.D.; Dymoke-Bradshaw, A.K.L.

    1996-09-01

    There are many different types of measurements that require a continuous time history of x-ray emission that can be provided with an x-ray streak camera. In order to properly analyze the images that are recorded with the x-ray streak cameras operated on Nova, it is important to account for the streak characterization of each camera. We have performed a number of calibrations of the streak cameras both on the bench as well as with Nova disk target shots where we use a time modulated laser intensity profile (self-beating of the laser) on the target to generate an x-ray comb. We have measured the streak camera sweep direction and spatial offset, curvature of the electron optics, sweep rate, and magnification and resolution of the electron optics.

  10. Characterization of X-ray streak cameras for use on Nova

    SciTech Connect

    Kalantar, D.H.; Bell, P.M.; Costa, R.L.; Hammel, B.A.; Landen, O.L.; Orzechowski, T.J.; Hares, J.D.; Dymoke-Bradshaw, A.K.L.

    1996-10-01

    There are many different types of measurements that require a continuous time history of x-ray emission that can be provided with an x-ray streak camera. In order to properly analyze the images that are recorded with the x-ray streak cameras operated on Nova, it is important to account for the streak characterization of each camera. We have performed a number of calibrations of the streak cameras both on the bench as well as with Nova disk target shots where we use a time modulated laser intensity profile (self-beating of the laser) an the target to generate an x-ray comb. We have measured the streak camera sweep direction and spatial offset, curvature of the electron optics, sweep rate, and magnification and resolution of the electron optics.

  11. On the convectively unstable nature of optimal streaks in boundary layers

    NASA Astrophysics Data System (ADS)

    Brandt, Luca; Cossu, Carlo; Chomaz, Jean-Marc; Huerre, Patrick; Henningson, Dan S.

    2003-06-01

    The objective of the study is to determine the absolute/convective nature of the secondary instability experienced by finite-amplitude streaks in the flat-plate boundary layer. A family of parallel streaky base flows is defined by extracting velocity profiles from direct numerical simulations of nonlinearly saturated optimal streaks. The computed impulse response of the streaky base flows is then determined as a function of streak amplitude and streamwise station. Both the temporal and spatio-temporal instability properties are directly retrieved from the impulse response wave packet, without solving the dispersion relation or applying the pinching point criterion in the complex wavenumber plane. The instability of optimal streaks is found to be unambiguously convective for all streak amplitudes and streamwise stations. It is more convective than the Blasius boundary layer in the absence of streaks; the trailing edge-velocity of a Tollmien Schlichting wave packet in the Blasius boundary layer is around 35% of the free-stream velocity, while that of the wave packet riding on the streaky base flow is around 70%. This is because the streak instability is primarily induced by the spanwise shear and the associated Reynolds stress production term is located further away from the wall, in a larger velocity region, than for the Tollmien Schlichting instability. The streak impulse response consists of the sinuous mode of instability triggered by the spanwise wake-like profile, as confirmed by comparing the numerical results with the absolute/convective instability properties of the family of two-dimensional wakes introduced by Monkewitz (1988). The convective nature of the secondary streak instability implies that the type of bypass transition studied here involves streaks that behave as amplifiers of external noise.

  12. Dilution jet mixing program

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; Coleman, E.; Johnson, K.

    1984-01-01

    Parametric tests were conducted to quantify the mixing of opposed rows of jets (two-sided injection) in a confined cross flow. Results show that jet penetrations for two sided injections are less than that for single-sided injections, but the jet spreading rates are faster for a given momentum ratio and orifice plate. Flow area convergence generally enhances mixing. Mixing characteristics with asymmetric and symmetric convergence are similar. For constant momentum ratio, the optimum S/H(0) with in-line injections is one half the optimum value for single sided injections. For staggered injections, the optimum S/H(0) is twice the optimum value for single-sided injection. The correlations developed predicted the temperature distributions within first order accuracy and provide a useful tool for predicting jet trajectory and temperature profiles in the dilution zone with two-sided injections.

  13. Standard dilution analysis.

    PubMed

    Jones, Willis B; Donati, George L; Calloway, Clifton P; Jones, Bradley T

    2015-02-17

    Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES. PMID:25599250

  14. Differential recovery of Streptococcus mutans from various mitis-salivarius agar preparations.

    PubMed Central

    Liljemark, W F; Okrent, D H; Bloomquist, C G

    1976-01-01

    Recoveries of Streptococcus mutans from human dental plaque were lower when plated on mitis-salivarius agar obtained from Baltimore Biological Laboratories as compared with mitis-salivarius agar obtained from Difco Laboratories. However, no difference in recoveries of established laboratory strains of S. mutans was observed between these two agar preparations. PMID:956358

  15. Electrospinning of agar/PVA aqueous solutions and its relation with rheological properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, we report the successful fabrication of agar-based nanofibers by an electrospinning technique using water as the solvent media. A tubeless spinneret was attached inside the electrospinning chamber, operated at 50 deg C, to avoid agar gelation. Pure agar solution 1% (w/w) showed inadequ...

  16. High-speed TV cameras for streak tube readout

    SciTech Connect

    Yates, G.J.; Gallegos, R.A.; Holmes, V.H. ); Turko, B.T. )

    1991-01-01

    Two fast framing TV cameras have been characterized and compared as readout media for imaging of 40 mm diameter streak tube (P-11) phosphor screens. One camera is based upon a Focus-Projection-Scan (FPS) high-speed electrostatic deflected vidicon with 30-mm-diameter PbO target. The other uses an interline transfer charge-coupled device (CCD) with 8.8 {times} 11.4 mm rectangular Si target. The field-of-view (FOV), resolution, responsivity, and dynamic range provided by both cameras when exposed to short duration ({approx} 10 {mu} full width at half maximum (FWHM)) transient illumination followed by a single field readout period of {lt}3 ms are presented. 11 refs., 8 figs., 3 tabs.

  17. Interference effects in angular streaking with a rotating terahertz field

    NASA Astrophysics Data System (ADS)

    Kazansky, A. K.; Bozhevolnov, A. V.; Sazhina, I. P.; Kabachnik, N. M.

    2016-01-01

    A method of angular streaking with a rotating terahertz electric field for photoelectrons produced by femtosecond extreme ultraviolet pulses is suggested and theoretically analyzed. The method can be used for free electron laser (FEL) pulse characterization on a shot-to-shot basis. It is shown that in related measurements an interesting phenomenon appears: formation of very bright and sharp features in the angular resolved electron spectra measured in the plane perpendicular to the collinear beam direction. These features are similar to the conventional caustics in the wave propagation. The caustics are accompanied by a well-developed interference structure. The intensity distribution along the caustic is determined by the envelope of the FEL pulse.

  18. Steering continuum electron dynamics by low-energy attosecond streaking

    NASA Astrophysics Data System (ADS)

    Geng, Ji-Wei; Xiong, Wei-Hao; Xiao, Xiang-Ru; Gong, Qihuang; Peng, Liang-You

    2016-08-01

    A semiclassical model is developed to understand the electronic dynamics in the low-energy attosecond streaking. Under a relatively strong infrared (IR) pulse, the low-energy part of photoelectrons initialized by a single attosecond pulse (SAP) can either rescatter with the ionic core and induce interferences structures in the momentum spectra of the ionized electrons or be recaptured into the Rydberg states. The Coulomb potential plays essential roles in both the electron rescattering and recapturing processes. We find that by changing the time delay between the SAP and the IR pulse, the photoelectrons yield or the population of the Rydberg states can be effectively controlled. The present study demonstrates a fascinating way to steer the electron motion in the continuum.

  19. Cloning and sequence analysis of banana streak virus DNA.

    PubMed

    Harper, G; Hull, R

    1998-01-01

    Banana streak virus (BSV), a member of the Badnavirus group of plant viruses, causes severe problems in banana cultivation, reducing fruit yield and restricting plant breeding and the movement of germplasm. Current detection methods are relatively insensitive. In order to develop a PCR-based diagnostic method that is both reliable and sensitive, the genome of a Nigerian isolate of BSV has been sequenced and shown to comprise 7389 bp and to be organized in a manner characteristic of badnaviruses. Comparison of this sequence with those of other badnaviruses showed that BSV is a distinct virus. PCR with primers based on sequence data indicated that BSV sequences are present in the banana genome. PMID:9926402

  20. StreakDet data processing and analysis pipeline for space debris optical observations

    NASA Astrophysics Data System (ADS)

    Virtanen, Jenni; Flohrer, Tim; Muinonen, Karri; Granvik, Mikael; Torppa, Johanna; Poikonen, Jonne; Lehti, Jussi; Santti, Tero; Komulainen, Tuomo; Naranen, Jyri

    We describe a novel data processing and analysis pipeline for optical observations of space debris. The monitoring of space object populations requires reliable acquisition of observational data, to support the development and validation of space debris environment models, the build-up and maintenance of a catalogue of orbital elements. In addition, data is needed for the assessment of conjunction events and for the support of contingency situations or launches. The currently available, mature image processing algorithms for detection and astrometric reduction of optical data cover objects that cross the sensor field-of-view comparably slowly, and within a rather narrow, predefined range of angular velocities. By applying specific tracking techniques, the objects appear point-like or as short trails in the exposures. However, the general survey scenario is always a “track before detect” problem, resulting in streaks, i.e., object trails of arbitrary lengths, in the images. The scope of the ESA-funded StreakDet (Streak detection and astrometric reduction) project is to investigate solutions for detecting and reducing streaks from optical images, particularly in the low signal-to-noise ratio (SNR) domain, where algorithms are not readily available yet. For long streaks, the challenge is to extract precise position information and related registered epochs with sufficient precision. Although some considerations for low-SNR processing of streak-like features are available in the current image processing and computer vision literature, there is a need to discuss and compare these approaches for space debris analysis, in order to develop and evaluate prototype implementations. In the StreakDet project, we develop algorithms applicable to single images (as compared to consecutive frames of the same field) obtained with any observing scenario, including space-based surveys and both low- and high-altitude populations. The proposed processing pipeline starts from the

  1. Illusory Streaks from Corners and Their Perceptual Integration

    PubMed Central

    Roncato, Sergio; Guidi, Stefano; Parlangeli, Oronzo; Battaglini, Luca

    2016-01-01

    Perceptual grouping appears both as organized forms of real figural units and as illusory or “phantom” figures. The phenomenon is visible in the Hermann grid and in configurations which generate color spreading, e.g., “neon effects.” These configurations, generally regular repetitive patterns, appear to be crossed by illusory bands filled with a brighter shade or a colored tinge connecting the various loci of illusory effects. In this work, we explore a particular new illusion showing a grouping effect. It manifests as illusory streaks irradiating from the vertexes of angular contours and connecting pairs of figures nearby. It is only clearly visible when more than one figure is shown, and takes the shape of a net crossing their corners. Although the grouping effect is vivid, the local source of the illusion is completely hidden. Theories explaining this effect as due to the irradiation of illusory streaks (mainly that of Grossberg and Mingolla, 1985a,b) do not fully explain the figural patterns presented here. Illusory effects have already been documented at the angles of various figures, causing them to alter in amplitude and brightness; however, the figure illustrated here appears to have different features and location. Phenomenological observations and an experiment were conducted to assess the role played by geometric and photometric parameters in this illusion. Results showed that sharp angles, in low contrast with the surround, are the main source of the illusion which, however, only becomes visible when at least two figures are close together. These findings are discussed with respect to theories of contour processing and perceptual grouping, and in relation to other illusions. PMID:27445922

  2. Illusory Streaks from Corners and Their Perceptual Integration.

    PubMed

    Roncato, Sergio; Guidi, Stefano; Parlangeli, Oronzo; Battaglini, Luca

    2016-01-01

    Perceptual grouping appears both as organized forms of real figural units and as illusory or "phantom" figures. The phenomenon is visible in the Hermann grid and in configurations which generate color spreading, e.g., "neon effects." These configurations, generally regular repetitive patterns, appear to be crossed by illusory bands filled with a brighter shade or a colored tinge connecting the various loci of illusory effects. In this work, we explore a particular new illusion showing a grouping effect. It manifests as illusory streaks irradiating from the vertexes of angular contours and connecting pairs of figures nearby. It is only clearly visible when more than one figure is shown, and takes the shape of a net crossing their corners. Although the grouping effect is vivid, the local source of the illusion is completely hidden. Theories explaining this effect as due to the irradiation of illusory streaks (mainly that of Grossberg and Mingolla, 1985a,b) do not fully explain the figural patterns presented here. Illusory effects have already been documented at the angles of various figures, causing them to alter in amplitude and brightness; however, the figure illustrated here appears to have different features and location. Phenomenological observations and an experiment were conducted to assess the role played by geometric and photometric parameters in this illusion. Results showed that sharp angles, in low contrast with the surround, are the main source of the illusion which, however, only becomes visible when at least two figures are close together. These findings are discussed with respect to theories of contour processing and perceptual grouping, and in relation to other illusions. PMID:27445922

  3. Culture of Piscirickettsia salmonis on enriched blood agar.

    PubMed

    Mauel, Michael J; Ware, Cynthia; Smith, Pedro A

    2008-03-01

    Piscirickettsia salmonis is the etiologic agent of piscirickettsiosis, an economically significant disease of fish. Isolation of P. salmonis by culturing on fish cell lines has been the standard technique since the initial isolation of the organism. The ability to grow P. salmonis on artificial media would relieve facilities of the cost of maintaining cell lines, permit isolation at fish culture sites with fewer contamination problems, and allow easier transport of isolates to diagnostic facilities for confirmation assays. This report describes the successful culture of P. salmonis on enriched blood agar. PMID:18319435

  4. Agar-Gel Precipitin Technique in Anthrax Antibody Determinations1

    PubMed Central

    Ray, John G.; Kadull, Paul J.

    1964-01-01

    A modification of the agar-gel precipitation inhibition technique of Thorne and Belton for detecting anthrax antibodies reduces inconsistency of visually determined end points on the same sera observed by different technicians. Determination of the minimal reacting concentrations of the anthrax antigen and antibody reagents, modifications of the visualization apparatus, methods for combining reagents, and length of incubation periods contribute to the ease of the end-point determinations and the uniformity of results. When compared with the previous technique, the modified procedure is less time-consuming while retaining satisfactory reproducibility, simplicity, specificity, and sensitivity. Images FIG. 1 FIG. 2 PMID:14201088

  5. Isotope dilution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Heumann, Klaus G.

    1992-09-01

    In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of

  6. Dust Devils Seen Streaking Across Mars: PART 1--What Are These?

    NASA Technical Reports Server (NTRS)

    2000-01-01

    PIA02376 [figure removed for brevity, see original site]

    Dark streaks, everywhere! Many Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images of the middle latitudes of the northern and southern hemispheres of Mars show wild patterns of criss-crossing dark streaks. Many of these streaks are straight and narrow, others exhibit curly arcs, twists, and loops. They often cross over hills, run straight across dunes and ripples, and go through fields of house-sized boulders. The two examples shown above were acquired in the last three months. Both pictures are illuminated by sunlight from the upper left. The first picture (left), showing dark streaks on the rippled flats of Argyre Planitia, covers an area 3 km by 5 km (1.9 by 3.1 miles) at a latitude of 51oS. The second picture (right) shows an area approximately 3 km by 5 km in Promethei Terra at a latitude of 58oS.

    For many months the MOC science team was seeing streaks such as these, but were uncertain how they formed. One speculation was that they might result from the passage of dust devils. Each dust devil would leave a dark streak by removing bright dust from the terrain in its path, revealing a darker surface underneath. An image described by the MOC team in July 1998 showed examples of streaks that were, at the time, speculated to be caused by dust devils.

  7. Flat-field response and geometric distortion measurements of optical streak cameras

    SciTech Connect

    Montgomery, D.S.; Drake, R.P.; Jones, B.A.; Wiedwald, J.D.

    1987-08-01

    To accurately measure pulse amplitude, shape, and relative time histories of optical signals with an optical streak camera, it is necessary to correct each recorded image for spatially-dependent gain nonuniformity and geometric distortion. Gain nonuniformities arise from sensitivity variations in the streak-tube photocathode, phosphor screen, image-intensifier tube, and image recording system. These nonuniformities may be severe, and have been observed to be on the order of 100% for some LLNL optical streak cameras. Geometric distortion due to optical couplings, electron-optics, and sweep nonlinearity not only affects pulse position and timing measurements, but affects pulse amplitude and shape measurements as well. By using a 1.053-..mu..m, long-pulse, high-power laser to generate a spatially and temporally uniform source as input to the streak camera, the combined effects of flat-field response and geometric distortion can be measured under the normal dynamic operation of cameras with S-1 photocathodes. Additionally, by using the same laser system to generate a train of short pulses that can be spatially modulated at the input of the streak camera, we can effectively create a two-dimensional grid of equally-spaced pulses. This allows a dynamic measurement of the geometric distortion of the streak camera. We will discuss the techniques involved in performing these calibrations, will present some of the measured results for LLNL optical streak cameras, and will discuss software methods to correct for these effects. 6 refs., 6 figs.

  8. Stress in dilute suspensions

    NASA Technical Reports Server (NTRS)

    Passman, Stephen L.

    1989-01-01

    Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the other hand, the so-called averaging theory starts with a determined system, but the very process of averaging renders the resulting system underdetermined. A third type of theory is proposed in which the kinetic theory of gases is used to motivate continuum equations for the suspended particles. This entails an interpretation of the stress in the particles that is different from the usual one. Classical theory is used to describe the motion of the suspending medium. The result is a determined system for a dilute suspension. Extension of the theory to more concentrated systems is discussed.

  9. Borelli's lactritmel agar induces conidiation in rare-macroconidia producing dermatophytic fungi.

    PubMed

    Ilkit, Macit; Gümral, Ramazan; Döğen, Aylin

    2012-10-01

    Macroconidia are among the most important indicators used to identify dermatophytic fungi, but several do not usually sporulate and/or produce macroconidia on Sabouraud glucose agar. Specifically, Microsporum audouinii, M. ferrugineum, Trichophyton concentricum, T. schoenleinii, T. verrucosum, and T. violaceum (including T. soudanense and T. yaoundei) rarely form macroconidia and, therefore, cannot be easily identified. In this study, we investigated the production of macroconidia on nine common laboratory media, including Borelli's lactritmel agar (BLA), modified Borelli's lactritmel agar (MBLA), brain heart infusion agar (BHIA), Christensen's urease agar in Petri dishes (UPA), cornmeal dextrose agar (CMDA), Lowenstein-Jensen agar (LJA), malt extract agar (MEA), oatmeal agar (OA), and potato dextrose agar (PDA). The performance of these media was evaluated using 18 rare-macroconidia producing isolates, including representative of the six species mentioned above. All cultures in this study were incubated at 26°C on the bench, and conidia formation on each was investigated at 5, 10, 15, 20, 25, and 30 days of incubation. BLA apparently improved macroconidia production after 15 days and was the most useful nutrient agar medium to induce these phenotypic characters in daily practice, closely followed by OA, PDA, and MBLA. PMID:22563856

  10. Physicochemical properties of biodegradable polyvinyl alcohol-agar films from the red algae Hydropuntia cornea.

    PubMed

    Madera-Santana, Tomás J; Robledo, Daniel; Freile-Pelegrín, Yolanda

    2011-08-01

    Agar obtained from the red alga Hydropuntia cornea was blended with polyvinyl alcohol (PVOH) in order to produce biodegradable films. In this study, we compare the properties of biopolymeric films formulated with agars extracted from H. cornea collected at different seasons (rainy and dry) in the Gulf of Mexico coast and PVOH as synthetic matrix. The films were prepared at different agar contents (0%, 25%, 50%, 75%, and 100%) and their optical, mechanical, thermal, and morphological properties analyzed. The tensile strength of PVOH-agar films increased when agar content was augmented. The formulation with 50% agar from rainy season (RS) had a significant higher tensile strength when compared to those from dry season (DS; p < 0.05). Tensile modulus also displayed an increasing trend and likewise, for 50% and 75% agar blends from RS showed higher values than those from DS (p < 0.05). In contrast, elongation at break decreased as the agar content increased, independently of the season. Environmental scanning electron microscopy images of PVOH-agar 75% biofilms from RS showed a homogeneous structure with good interfacial adhesion between the two components. The changes evidenced in the FTIR spectrum of this blend suggest that hydrogen bonding is taking place between the agar ether linkages (C-O-C) and the hydroxyl groups (OH) of the PVOH. Based on the above mentioned results, blends of PVOH and 75% agar from H. cornea collected in rainy season showed good properties for applications in the biodegradable packaging industry. PMID:21207092

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

    PubMed

    Tsai, C E; Kondo, F

    2001-03-01

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

  12. Stabilization of the hypersonic boundary layer by finite-amplitude streaks

    NASA Astrophysics Data System (ADS)

    Ren, Jie; Fu, Song; Hanifi, Ardeshir

    2016-02-01

    Stabilization of two-dimensional disturbances in hypersonic boundary layer flows by finite-amplitude streaks is investigated using nonlinear parabolized stability equations. The boundary-layer flows at Mach numbers 4.5 and 6.0 are studied in which both first and second modes are supported. The streaks considered here are driven either by the so-called optimal perturbations (Klebanoff-type) or the centrifugal instability (Görtler-type). When the streak amplitude is in an appropriate range, i.e., large enough to modulate the laminar boundary layer but low enough to not trigger secondary instability, both first and second modes can effectively be suppressed.

  13. Improvements in Off-Center Focusing in an X-ray Streak Camera

    SciTech Connect

    McDonald, J W; Weber, F; Holder, J P; Bell, P M

    2003-07-17

    Due to the planar construction of present x-ray streak tubes significant off-center defocusing is observed in both static and dynamic images taken with one-dimensional resolution slits. Based on the streak tube geometry curved photocathodes with radii of curvature ranging from 3.5 to 18 inches have been fabricated. We report initial off-center focusing performance data on the evaluation of these ''improved'' photocathodes in an X-ray streak camera and an update on the theoretical simulations to predict the optimum cathode curvature.

  14. Ultra Fast X-ray Streak Camera for TIM Based Platforms

    SciTech Connect

    Marley, E; Shepherd, R; Fulkerson, E S; James, L; Emig, J; Norman, D

    2012-05-02

    Ultra fast x-ray streak cameras are a staple for time resolved x-ray measurements. There is a need for a ten inch manipulator (TIM) based streak camera that can be fielded in a newer large scale laser facility. The LLNL ultra fast streak camera's drive electronics have been upgraded and redesigned to fit inside a TIM tube. The camera also has a new user interface that allows for remote control and data acquisition. The system has been outfitted with a new sensor package that gives the user more operational awareness and control.

  15. Emissivity spectrum of a large "dark streak" from themis infrared imagery

    SciTech Connect

    Brumby, Steven P.; Vaniman, D. T.; Bish, D. L.

    2003-01-01

    'Dark streaks', also known as 'slope streaks', are unusual surface features found on Mars that are known to appear and fade away on timescales of years. Various explanations have been proposed for their origin and composition, including dry avalanches and wet debris or precipitates from brines. Previous investigations have been based on analysis of panchromatic imagery and altimetry from Viking and Mars Global Surveyor missions. We have obtained an infrared emissivity spectrum of a large dark streak on the north western edge of Olympus Mons, using imagery from the THEMIS instrument on the Mars Odyssey 2001 spacecraft.

  16. Agar gel immunodiffusion test for the detection of bovine leukemia virus antibodies: lack of trans-Atlantic standardization.

    PubMed Central

    Simard, C; Richardson, S; Dixon, P; Komal, J

    2000-01-01

    Two agar gel immunodiffusion (AGID) kits for the serodiagnosis of bovine leukemia virus (BLV) were imported from Europe and were compared with North American kits. The BLV AGID kits from North America and from Europe differed significantly. The punches were different, as were the pattern distribution in the agar of the reference and the test sera, resulting in differences in the reading of the immunoprecipitation lines. Based on the testing of 1200 serum samples from cattle, the European kits gave a good correlation with the American kits, as indicated by their respective kappa values. However, the European kits were found to be less sensitive when evaluated against weakly positive samples from field specimens or following a dilution trial. Only 65% and 50% of the weakly positive samples detected by the American kit #1 were detected by the European kits #2 and #3, respectively. The American kit was also capable of detecting BLV antibodies in 45% of strongly positive samples diluted 1/50 in negative sera, while antibodies were detected in only 15% of the samples with the European kit #2 and in none of the samples with the European kit #3. False negatives were also detected with the European kits. Among the false negatives, the degree of expected reactions was weak (European kit #2) or of varying degrees of positivity (European kit #3). Besides the differences in format and performance, the BLV-AGID kits in Europe are evaluated with the National Standard Serum E4 while a proficiency panel composed of a quadruplicate set of 10 reference sera is used in Canada to monitor the kits. Based on the overall observations, we noted a lack of standardization between the BLV-AGID kits used in North America and in Europe. PMID:10805247

  17. Analyses of Twelve New Whole Genome Sequences of Cassava Brown Streak Viruses and Ugandan Cassava Brown Streak Viruses from East Africa: Diversity, Supercomputing and Evidence for Further Speciation.

    PubMed

    Ndunguru, Joseph; Sseruwagi, Peter; Tairo, Fred; Stomeo, Francesca; Maina, Solomon; Djikeng, Appolinaire; Djinkeng, Appolinaire; Kehoe, Monica; Boykin, Laura M

    2015-01-01

    Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) which are frequently found infecting cassava, one of sub-Saharan Africa's most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production. PMID:26439260

  18. Analyses of Twelve New Whole Genome Sequences of Cassava Brown Streak Viruses and Ugandan Cassava Brown Streak Viruses from East Africa: Diversity, Supercomputing and Evidence for Further Speciation

    PubMed Central

    Ndunguru, Joseph; Sseruwagi, Peter; Tairo, Fred; Stomeo, Francesca; Maina, Solomon; Djinkeng, Appolinaire; Kehoe, Monica; Boykin, Laura M.

    2015-01-01

    Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) which are frequently found infecting cassava, one of sub-Saharan Africa’s most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production. PMID:26439260

  19. Dilution refrigeration for space applications

    NASA Technical Reports Server (NTRS)

    Israelsson, U. E.; Petrac, D.

    1990-01-01

    Dilution refrigerators are presently used routinely in ground based applications where temperatures below 0.3 K are required. The operation of a conventional dilution refrigerator depends critically on the presence of gravity. To operate a dilution refrigerator in space many technical difficulties must be overcome. Some of the anticipated difficulties are identified in this paper and possible solutions are described. A single cycle refrigerator is described conceptually that uses forces other than gravity to function and the stringent constraints imposed on the design by requiring the refrigerator to function on the earth without using gravity are elaborated upon.

  20. Streak camera recording of shock wave transit times at large distances using laser illumination

    NASA Astrophysics Data System (ADS)

    Tyburczy, J. A.; Blayney, J. L.; Miller, W. F.; Ahrens, T. J.

    1984-09-01

    A pulsed laser illumination system for streak camera recording of impact-induced shock wave transit times (˜1 μs) during impact experiments is described. Laser illumination of centimeter-sized subjects offers many advantages over diffuse illumination techniques for streak photography. Source-to-sample and sample-to-camera distances of ˜100 to 102 m can be employed. Light filtering, and simultaneous recording of both the impact event and the camera streak rate calibration, can be carried out easily. For use in such a system we describe a Pockels cell controller in which the reference 10-MHz oscillator signal is synchronously divided down to 38 Hz to provide a trigger signal for laser and streak camera testing.

  1. Effect of Process Variables on the Formation of Streak Defects on Anodized Aluminum Extrusions: An Overview

    NASA Astrophysics Data System (ADS)

    Zhu, Hanliang; Couper, Malcolm J.; Dahle, Arne K.

    2012-04-01

    Streak defects are often present on anodized extrusions of 6xxx series aluminum alloys, increasing the fabrication cost of these products. Moreover, streaking often only becomes visible after etching and anodizing treatments, rather than in the as-extruded condition, making it difficult to identify the original causes and influencing factors of these defects. In this paper, various process variables that influence the formation of streak defects on anodized aluminium extrusions are reviewed on the basis of a literature review, industrial practice and experimental results. The influencing factors involved in various processing steps such as billet quality, extrusion process, die design and etching process are considered. Effective measures for preventing the formation of streak defects in industrial extrusion products are discussed.

  2. Standard design for National Ignition Facility x-ray streak and framing cameras

    SciTech Connect

    Kimbrough, J. R.; Bell, P. M.; Bradley, D. K.; Holder, J. P.; Kalantar, D. K.; MacPhee, A. G.; Telford, S.

    2010-10-15

    The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube.

  3. Standard design for National Ignition Facility x-ray streak and framing camerasa)

    NASA Astrophysics Data System (ADS)

    Kimbrough, J. R.; Bell, P. M.; Bradley, D. K.; Holder, J. P.; Kalantar, D. K.; MacPhee, A. G.; Telford, S.

    2010-10-01

    The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube.

  4. Evaluation of eight agar media for the isolation of shiga toxin-Producing Escherichia coli.

    PubMed

    Gill, Alexander; Huszczynski, George; Gauthier, Martine; Blais, Burton

    2014-01-01

    The growth characteristics of 96 shiga toxin-producing Escherichia coli (STEC) strains representing 36 different O-types (including priority O types O26, O45, O103, O111, O121, O145 and O157) on commercial and in-house agar media were studied. The ability of the strains to grow on agar media with varying selective supplement formulations was evaluated using MacConkey Agar (MAC); Rainbow® Agar O157 (RBA); Rainbow® Agar O157 with manufacturer-recommended selective supplements (RBA-NT); Rainbow® Agar O157 with USDA-recommended selective supplements (RBA-USDA); CHROMagar STEC™ (CH STEC); Tryptone Bile agar containing cefixime and tellurite (TBA-CT); Tryptone Bile agar containing cefixime, tellurite, eosin and methylene blue (TBA-EM); and VTEC agar. All of the strains were able to grow on MAC, RBA and VTEC agar, whereas a number of strains (including some non-O157 priority O types) were unable to grow on the highly selective media CH STEC, RBA-NT, RBA-USDA, TBA-EM and TBA-CT. Only RBA-NT and CH STEC exhibited significant inhibition of background flora from ground beef enrichment. Significant inhibition of background flora from beef trim enrichment was observed with RBA-NT, RBA-USDA, CH STEC, TBA-EM and VTEC agar. With exception of E. coli O157, several different colony morphologies were observed on the differential plating media among strains of the same O type, indicating that this colony morphology is not a reliable means of identifying target STEC. These results suggest that an approach to maximize the recovery of target STEC from beef enrichment cultures is dual plating on lesser (RBA, MAC, VTEC agar) and more highly (RBA-NT, CH STEC) selective agars. PMID:24211606

  5. Characterization of Leptospiral Chemoreceptors Using a Microscopic Agar Drop Assay.

    PubMed

    Affroze, Samia; Islam, Md Shafiqul; Takabe, Kyosuke; Kudo, Seishi; Nakamura, Shuichi

    2016-08-01

    Bacterial chemotaxis is induced by sensing chemical stimuli via chemoreceptors embedded in the cytoplasmic membrane, enabling the cells to migrate toward nutrients or away from toxins. The chemoreceptors of Escherichia coli and Salmonella spp. have been well studied and are functionally classified on the basis of detectable substrates. The spirochete Leptospira possesses more than ten chemoreceptors and shows attractive or repellent responses against some sugars, amino acids, and fatty acids. However, the roles of these chemoreceptors have not been investigated. In this study, we conducted a chemotaxis assay called microscopic agar drop assay in combination with competition experiments, determining whether two kinds of attractants are recognized by the same type of chemoreceptor in the saprophytic Leptospira strain, Leptospira biflexa. Analyzing the competition effect observed between several pairs of chemicals, we found that L. biflexa senses sugars via chemoreceptors different from those that sense amino acids and fatty acids. PMID:27109059

  6. Split ring resonator based THz-driven electron streak camera featuring femtosecond resolution

    PubMed Central

    Fabiańska, Justyna; Kassier, Günther; Feurer, Thomas

    2014-01-01

    Through combined three-dimensional electromagnetic and particle tracking simulations we demonstrate a THz driven electron streak camera featuring a temporal resolution on the order of a femtosecond. The ultrafast streaking field is generated in a resonant THz sub-wavelength antenna which is illuminated by an intense single-cycle THz pulse. Since electron bunches and THz pulses are generated with parts of the same laser system, synchronization between the two is inherently guaranteed. PMID:25010060

  7. Streak detection and analysis pipeline for space-debris optical images

    NASA Astrophysics Data System (ADS)

    Virtanen, Jenni; Poikonen, Jonne; Säntti, Tero; Komulainen, Tuomo; Torppa, Johanna; Granvik, Mikael; Muinonen, Karri; Pentikäinen, Hanna; Martikainen, Julia; Näränen, Jyri; Lehti, Jussi; Flohrer, Tim

    2016-04-01

    We describe a novel data-processing and analysis pipeline for optical observations of moving objects, either of natural (asteroids, meteors) or artificial origin (satellites, space debris). The monitoring of the space object populations requires reliable acquisition of observational data, to support the development and validation of population models and to build and maintain catalogues of orbital elements. The orbital catalogues are, in turn, needed for the assessment of close approaches (for asteroids, with the Earth; for satellites, with each other) and for the support of contingency situations or launches. For both types of populations, there is also increasing interest to detect fainter objects corresponding to the small end of the size distribution. The ESA-funded StreakDet (streak detection and astrometric reduction) activity has aimed at formulating and discussing suitable approaches for the detection and astrometric reduction of object trails, or streaks, in optical observations. Our two main focuses are objects in lower altitudes and space-based observations (i.e., high angular velocities), resulting in long (potentially curved) and faint streaks in the optical images. In particular, we concentrate on single-image (as compared to consecutive frames of the same field) and low-SNR detection of objects. Particular attention has been paid to the process of extraction of all necessary information from one image (segmentation), and subsequently, to efficient reduction of the extracted data (classification). We have developed an automated streak detection and processing pipeline and demonstrated its performance with an extensive database of semisynthetic images simulating streak observations both from ground-based and space-based observing platforms. The average processing time per image is about 13 s for a typical 2k-by-2k image. For long streaks (length >100 pixels), primary targets of the pipeline, the detection sensitivity (true positives) is about 90% for

  8. Characterization results from several commercial soft x-ray streak cameras

    SciTech Connect

    Stradling, G.L.; Studebaker, J.K.; Cavailler, C.; Launspach, J.; Planes, J.

    1986-01-01

    The spatio-temporal performance of four soft x-ray streak cameras has been characterized. The objective in evaluating the performance capability of these instruments is to enable us to optimize experiment designs, to encourage quantitative analysis of streak data and to educate the ultra high speed photography and photonics community about the x-ray detector performance which is available. These measurements have been made collaboratively over the space of two years at the Forge pulsed x-ray source at Los Alamos and at the Ketjak laser facility an CEA Limeil-Valenton. The x-ray pulse lengths used for these measurements at these facilities were 150 psec and 50 psec respectively. The results are presented as dynamically-measured modulation transfer functions. Limiting temporal resolution values were also calculated. Emphasis is placed upon shot noise statistical limitations in the analysis of the data. Space charge repulsion in the streak tube limits the peak flux at ultra short experiments duration times. This limit results in a reduction of total signal and a decrease in signal to noise ratio in the streak image. The four cameras perform well with 20 1p/mm resolution discernable in data from the French C650X, the Hadland X-Chron 540 and the Hamamatsu C1936X streak cameras. The Kentech x-ray streak camera has lower modulation and does not resolve below 10 1p/mm but has a longer photocathode. The C650X bi-lamellar design shows uniform high fidelity recording across both spatial and temporal dimensions. The other three streak cameras show resolution degradation off axis. This must be weighed against a 10X lower streak tube throughput for the C650X.

  9. Intial synchroscan streak camera imaging at the A0 photoinjector

    SciTech Connect

    Lumpkin, A.H.; Ruan, J.; /Fermilab

    2008-04-01

    At the Fermilab A0 photoinjector facility, bunch-length measurements of the laser micropulse and the e-beam micropulse have been done in the past with a single-sweep module of the Hamamatsu C5680 streak camera with an intrinsic shot-to-shot trigger jitter of 10 to 20 ps. We have upgraded the camera system with the synchroscan module tuned to 81.25 MHz to provide synchronous summing capability with less than 1.5-ps FWHM trigger jitter and a phase-locked delay box to provide phase stability of {approx}1 ps over 10s of minutes. This allowed us to measure both the UV laser pulse train at 244 nm and the e-beam via optical transition radiation (OTR). Due to the low electron beam energies and OTR signals, we typically summed over 50 micropulses with 1 nC per micropulse. We also did electron beam bunch length vs. micropulse charge measurements to identify a significant e-beam micropulse elongation from 10 to 30 ps (FWHM) for charges from 1 to 4.6 nC. This effect is attributed to space-charge effects in the PC gun as reproduced by ASTRA calculations. Chromatic temporal dispersion effects in the optics were also characterized and will be reported.

  10. An Optical Streaking Method for Measuring Femtosecond Electron Bunches

    SciTech Connect

    Ding, Yuantao; Bane, Karl L.F.; Huang, Zhirong; /SLAC

    2011-12-14

    The measurement of the ultra-short electron bunch length on the femtosecond time scale constitutes a very challenging problem. In the x-ray free electron laser facilities such as the Linac Coherent Light Source, generation of a sub-ten femtoseconds electron beam with 20pC charge is possible, but direct measurements are very difficult due to the resolution limit of the present diagnostics. We propose a new method here based on the measurement of the electron beam energy modulation induced from laser-electron interaction in a short wiggler. A typical optical streaking method requires a laser wavelength much longer than the electron bunch length. In this paper a laser with its wavelength shorter than the electron bunch length has been adopted, while the slope on the laser intensity envelope is used to distinguish the different periods. With this technique it is possible to reconstruct the bunch longitudinal profile from a single shot measurement. Generation of ultrashort x-ray pulses at femtoseconds (fs) scale is of great interest within synchrotron radiation and free electron laser (FEL) user community. One of the simple methods is to operate the FEL facility at low charge. At the Linac Coherent Light Source (LCLS), we have demonstrated the capability of generating ultrashort electron-beam (e-beam) with a duration of less than 10 fs fwhm using 20 pC charge. The x-ray pulses have been delivered to the x-ray users with a similar or even shorter pulse duration. However, The measurement of such short electron or x-ray pulse length at the fs time-scale constitutes a challenging problem. A standard method using an S-band radio-frequency (rf) transverse deflector has been established at LCLS, which works like a streak camera for electrons and is capable of resolving bunch lengths as short as 25 fs fwhm. With this device, the electrons are transversely deflected by the high-frequency time-variation of the deflecting fields. Increasing the deflecting voltage and rf frequency

  11. Black leaf streak disease affects starch metabolism in banana fruit.

    PubMed

    Saraiva, Lorenzo de Amorim; Castelan, Florence Polegato; Shitakubo, Renata; Hassimotto, Neuza Mariko Aymoto; Purgatto, Eduardo; Chillet, Marc; Cordenunsi, Beatriz Rosana

    2013-06-12

    Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots. PMID:23692371

  12. Polar Dunes In Summer Exhibit Frost Patches, Wind Streaks

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mars Global Surveyor passes over the north polar region of the red planet twelve times each day, offering many opportunities to observe how the polar cap frosts and dunes are changing as the days goby. Right now it is summer in the north. This picture, taken the second week of April 1999, shows darks and dunes and remnant patches of bright frost left over from the winter that ended in July 1998. Dark streaks indicate recent movement of sand. The picture covers an area only 1.4 kilometers (0.9 miles)across and is illuminated from the upper right.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  13. Intermittency in dilute granular flows

    NASA Astrophysics Data System (ADS)

    Guo, Wenxuan; Zhang, Qiang; Wylie, Jonathan J.

    2016-07-01

    In this letter, we show that dilute granular systems can exhibit a type of intermittency that has no analogue in gas dynamics. We consider a simple system in which a very dilute set of granular particles falls under gravity through a nozzle. This setting is analogous to the classical problem of high-speed nozzle flow in the study of compressible gases. It is well known that very dilute granular systems exhibit behavior qualitatively similar to gases, and that gas flowing through a nozzle does not exhibit intermittency. Nevertheless, we show that the intermittency in dilute granular nozzle flows can occur and corresponds to complicated transitions between supersonic and subsonic regimes. We also provide detailed explanations of the mechanism underlying this phenomenon.

  14. Optimizing Data Recording for the NIF Core Diagnostic X-ray Streak Camera

    SciTech Connect

    Kalantar, D H; Bell, P M; Perry, T S; Sewall, N; Diamond, C; Piston, K

    2000-06-13

    The x-ray streak camera is an important instrument for recording a continuous time history of x-ray emitted from laser target experiments. X-ray streak cameras were used to diagnose experiments in inertially confined fusion and high energy density sciences on the Nova laser. These streak cameras are now used for similar experiments conducted at the OMEGA laser facility, and cameras of this type will be used for experiments on the National Ignition Facility (NIF). The Nova x-ray streak cameras (SSCs) used a sealed optical image intensifier coupled to film to record the streaked x-ray data. In order to develop the core x-ray streak camera for NIF (ref Kimbrough) using a CCD based recording system, we evaluate the performance of the SSCs under a variety of detector configurations. We performed laboratory bench characterization tests of the SSCs to measure the spatial resolution and to evaluate the dynamic range and signal to noise for different configurations of the SSC. We present results of these tests here.

  15. Effects of streaking laser intensity on the characterization of isolated attosecond pulses

    NASA Astrophysics Data System (ADS)

    Wang, He; Khan, Sabih; Chini, Michael; Chen, Shouyuan; Chang, Zenghu

    2009-05-01

    Single isolated attosecond extreme ultraviolet (XUV) pulses can be characterized by streaking photoelectrons using a near infrared (NIR) laser field. Classically, the streaking resolution is determined by the Rayleigh criterion, which requires the minimum NIR intensity of 5.5x10^13 W/cm^2 to resolve 90 as XUV pulses. Under such high NIR intensity, the electrons generated from multi-photon processes overlap with the streaked electrons in the spectrogram, which unavoidably introduces errors in the final XUV reconstruction. When the FROG-CRAB (Frequency-Resolved Optical Gating for Complete Reconstruction of Attosecond Bursts) technique is used to reconstruct the XUV pulses from the spectrogram, it was found that the minimum streaking intensity needed to resolve single attosecond pulses is dependent on the maximum count of the spectrogram. With a peak count of 100 in the spectrogram, chirped attosecond pulses with spectral bandwidth supporting 90-as transform limited pulse durations can be retrieved from the spectrogram with streaking intensity two orders of magnitude smaller than that derived from the Rayleigh criterion. Such low streaking field intensity is desirable to suppress the ATI background, which is important for the characterization of even shorter XUV attosecond pulses because it significantly reduces the intensity constraints on the experiments.

  16. New observations of Bolivian wind streaks by JPL Airborne SAR: Preliminary results

    NASA Technical Reports Server (NTRS)

    Blumberg, Dan G.; Greeley, Ronald

    1995-01-01

    In 1993 NASA's Jet Propulsion Laboratory Airborne Synthetic Aperture Radar system (AIRSAR) was deployed to South America to collect multi-parameter radar data over pre-selected targets. Among the sites targeted was a series of wind streaks located in the Altiplano of Bolivia. The objective of this investigation is to study the effect of wavelength, polarization, and incidence angle on the visibility of wind streaks in radar data. Because this is a preliminary evaluation of the recently acquired data we will focus on one scene and, thus, only on the effects of wavelength and polarization. Wind streaks provide information on the near-surface prevailing winds and on the abundance of winderodible material, such as sand. The potential for a free-flyer radar system that could provide global radar images in multiple wavelengths, polarizations, and incidence angles requires definition of system parameters for mission planning. Furthermore, thousands of wind streaks were mapped from Magellan radar images of Venus; their interpretation requires an understanding of the interaction of radar with wind streaks and the surrounding terrain. Our experiment was conducted on wind streaks in the Altiplano of Bolivia to address these issues.

  17. On the origin and evolution of streaks in polymeric shear flows

    NASA Astrophysics Data System (ADS)

    Page, Jacob; Zaki, Tamer

    2013-11-01

    Streaks are a ubiquitous feature in transitional shear flows of both Newtonian and complex fluids. A model problem is formulated where streaks are generated in response to forcing by a decaying streamwise vortex in an Oldroyd-B fluid, and the effects of inertia and elasticity are examined. The dynamics are found to be largely governed by a single parameter: the ratio of the solvent diffusion to the polymer relaxation timescales. When the time scales are disparate, the ``quasi-Newtonian'' and ``elastic'' dynamics can be distinguished. The ``quasi-Newtonian'' evolution of the streaks in the polymeric flow matches the Newtonian equivalent at the same total (solvent) Reynolds number when polymer relaxation is very fast (slow). The ``elastic'' response is significant, when the polymer relaxation time is long, and leads to significant streak amplification even with very weak inertia. When the diffusion and polymer relaxation timescales are commensurate, the streaks are re-energised in a periodic cycle. This behaviour is enhanced in the instantaneously elastic limit where the governing equation reduces to a wave equation with harmonic forcing. The streak re-energisation is demonstrated to be a superposition of trapped inertio-elastic shear waves.

  18. Spatial relationships among the cellular tapetum, visual streak and rod density in dogs

    PubMed Central

    YAMAUE, Yasuhiro; HOSAKA, Yoshinao Z.; UEHARA, Masato

    2014-01-01

    The dog visual system is well suited to dim light conditions due to rod-dominated retina and the reflective tapetum. The topographical distributions of rods and thickness of the tapetum of the dog were quantified in retinal whole mounts stained with thionine, and spatial relationships among the tapetum, rod density and visual streak of high ganglion cell density were elucidated. The relationship between the retina and tapetum was analyzed in parasagittal sections stained with thionine or hematoxylin-eosin. The tapetum was thick in its center, and the thickest part consisted of 9 to 12 tapetal cell layers. Rod density ranged from 200,000 to 540,000/mm2. Maximum rod density was found in the area dorsal to the visual streak, and the density in that area was significantly higher than the rod density in the visual streak and accorded spatially with the thickest part of the tapetum. The horizontal visual streak was found over the horizontal line through the optic disc in the temporal half and extended slightly into the nasal half. The central area of the highest density of ganglion cells was approximately located midway between the nasal and temporal ends of the visual streak. The visual streak was located within the tapetal area, but ventrally to the thick part of the tapetum. PMID:25728250

  19. Seasonal and secular variation of wind streaks on Mars - An analysis of Mariner 9 and Viking data

    NASA Technical Reports Server (NTRS)

    Thomas, P.; Veverka, J.

    1979-01-01

    Viking orbiter observations extending over 1 Martian year have been used in conjunction with Mariner 9 data obtained in 1971-1972 to study the seasonal and secular behavior of several kinds of wind streaks. Most bright streaks, inferred to consist of dust storm fallout in the lees of obstacles, have changed very little in form or orientation over a period of 3 Martian years. Some are extremely stable and have experienced no effective eolian action over the 3 years. A few bright streaks changed rapidly during global dust storms; these streaks are located in areas subject to both global and topographic winds. Viking images have shown for the first time that dark, erosional streaks are stable from the time of their formation after major dust storms until the onset of the next episode of major storm activity. Available evidence shows that the large, dark streaks in Oxia Palus consist of material deflated from dune fields within the associated craters. These streaks lengthened secularly since 1972; changes appear to occur episodically during southern summer. The great majority of all streaks reflect winds during the period from late southern spring to early southern fall, although some changes occur throughout the year. The global pattern of wind streaks and the variability of the streaks thus depend strongly upon the current south-north asymmetry of seasons on Mars.

  20. Effects of Hot Streak Shape on Rotor Heating in a High-Subsonic Single-Stage Turbine

    NASA Technical Reports Server (NTRS)

    Dorney, Daniel J.; Gundy-Burlet, Karen L.; Norvig, Peter (Technical Monitor)

    1999-01-01

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine operating in high subsonic flow. In addition to a simulation of the baseline turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region.

  1. Comparison of ChromID Agar and Clostridium difficile Selective Agar for Effective Isolation of C. difficile from Stool Specimens

    PubMed Central

    Lee, Eun Joo

    2014-01-01

    Background ChromID Clostridium difficile agar (IDCd; bioMérieux SA, France) is a recently developed chromogenic medium for rapid and specific isolation of C. difficile. We compared the performance of IDCd with that of Clostridium difficile Selective Agar (CDSA). Methods A total of 530 fresh stool specimens were collected from patients with clinical signs compatible with C. difficile infection, and cultures for C. difficile were performed on IDCd and CDSA. C. difficile colonies were identified by spore staining, odor, use of an ANI identification test kit (bioMérieux SA), and multiplex PCR for tcdA, tcdB, and tpi. Results The concordance rate between IDCd and CDSA was 90.6% (480/530). The positivity rates on IDCd on days 1 and 2 (55.6% and 85.0%, respectively) were significantly higher than those on CDSA (19.4% and 75.6%, respectively) (P<0.001 for day 1 and P=0.02 for day 2), but the detection rates on IDCd and CDSA on day 3 were not different (89.4% vs. 82.8%, P=0.0914). On day 3, the recovery rates for non-C. difficile isolates on IDCd and CDSA were 30.2% (160/530) and 22.1% (117/530), respectively (P=0.0075). Clostridium spp. other than C. difficile were the most prevalent non-C. difficile isolates on both media. Conclusions The culture positivity rates on IDCd and CDSA were not different on day 3 but IDCd may allow for rapid and sensitive detection of C. difficile within 2 days of cultivation. PMID:24422190

  2. Residual Agar Determination in Bacterial Spores by Electrospray Ionization Mass Spectrometry

    SciTech Connect

    Wahl, Karen L.; Colburn, Heather A.; Wunschel, David S.; Petersen, Catherine E.; Jarman, Kristin H.; Valentine, Nancy B.

    2010-02-15

    Presented here is an analytical method to detect residual agar from a bacterial spore sample as an indication of culturing on an agar plate. This method is based on the resolubilization of agar polysaccharide from a bacterial spore sample, enzymatic digestion, followed by electrospray ionization tandem mass spectrometry (ESI-MSn) analysis for detection of a specific agar fragment ion. A range of Bacillus species and strains were selected to demonstrate the effectiveness of this approach. The characteristic agar fragment ion was detected in the spores grown on agar that were washed from 1 to 5 times, irradiated or non-irradiated and not in the spores grown in broth. A sample containing approximately 108 spores is currently needed for confident detection of residual agar from culture on agar plates in the presence of bacterial spores with a limit of detection of approximately 1 ppm agar spiked into a broth-grown spore sample. The results of a proficiency test with 42 blinded samples are presented demonstrating the utility of this method with no false positives and only 3 false negatives for samples that were below the detection level of the method as documented.

  3. Green synthesis of gold nanoparticles of different sizes and shapes using agar-agar water solution and femtosecond pulse laser irradiation

    NASA Astrophysics Data System (ADS)

    Almeida de Matos, Ricardo; da Silva Cordeiro, Thiago; Elgul Samad, Ricardo; Dias Vieira, Nilson; Coronato Courrol, Lilia

    2012-11-01

    We report a method to create gold nanoparticles of different sizes and shapes using agar-agar water solution and irradiation with light from a xenon lamp, followed by ultrashort laser pulses. No additives, such as solvents, surfactants or reducing agents, were used in the procedure. Laser irradiation (laser ablation) was important to the reduction of the nanoparticles diameter and formation of another shapes. Distilled water was used as solvent and agar-agar (hydrophilic colloid extracted from certain seaweeds) was important for the stabilization of gold nanoparticles, avoiding their agglomeration. The formation of gold nanoparticles was confirmed with ultraviolet-visible absorption and TEM microscopy. The gold nanoparticles acquired spherical, prism, and rod shapes depending on the laser parameters. Variation of laser irradiation parameters as pulse energy, irradiation time and repetition rate was assessed. The relevant mechanisms contributing for the gold nanoparticles production are discussed.

  4. Chiral oily streaks in a smectic-A liquid crystal.

    PubMed

    Nemitz, Ian R; Ferris, Andrew J; Lacaze, Emmanuelle; Rosenblatt, Charles

    2016-08-21

    The liquid crystal octylcyanobiphenyl (8CB) was doped with the chiral agent CB15 and spin-coated onto a substrate treated for planar alignment of the director, resulting in a film of thickness several hundred nm in the smectic-A phase. In both doped and undoped samples, the competing boundary conditions - planar alignment at the substrate and vertical alignment at the free surface - cause the liquid crystal to break into a series of flattened hemicylinders to satisfy the boundary conditions. When viewed under an optical microscope with crossed polarizers, this structure results in a series of dark and light stripes ("oily streaks") of period ∼1 μm. In the absence of chiral dopant the stripes run perpendicular to the substrate's easy axis. However, when doped with chiral CB15 at concentrations up to c = 4 wt%, the stripe orientation rotates by a temperature-dependent angle φ with respect to the c = 0 stripe orientation, where φ increases monotonically with c. φ is largest just below the nematic - smectic-A transition temperature TNA and decreases with decreasing temperature. As the temperature is lowered, φ relaxes to a steady-state orientation close to zero within ∼1 °C of TNA. We suggest that the rotation phenomenon is a manifestation of the surface electroclinic effect: The rotation is due to the weak smectic order parameter and resulting large director tilt susceptibility with respect to the smectic layer normal near TNA, in conjunction with an effective surface electric field due to polar interactions between the liquid crystal and substrate. PMID:27426740

  5. Glucose-sucrose-potassium tellurite-bacitracin agar, an alternative to mitis salivarius-bacitracin agar for enumeration of Streptococcus mutans.

    PubMed Central

    Tanzer, J M; Börjesson, A C; Laskowski, L; Kurasz, A B; Testa, M

    1984-01-01

    An agar medium for selective recovery and enumeration of Streptococcus mutans was developed as an alternative to mitis salivarius-bacitracin (MSB) agar. Combinations of dyes, antibiotics, and tellurite were added to a nonselective medium which, because of its sucrose content, allowed easy recognition of S. mutans colonies. Candle jar incubation for 2 days, by comparison with anaerobic incubation, reduced background flora but did not diminish S. mutans recoveries from clinical samples. Quantitative comparisons were made of the simultaneous recoveries of a number of authentic S. mutans serotype representatives and fresh clinical isolates, using various glucose-sucrose-potassium tellurite-bacitracin (GSTB) formulations and mitis salivarius, MSB, and blood agars. Mitis salivarius counts were not detectably different from blood counts, but counts on MSB were distinctly lower. A formulation of the new medium containing 5% glucose 5% sucrose, 0.001% potassium tellurite, 0.3 U of bacitracin per ml (hence GSTB), and 2% agar gave recoveries nearly equal to those on mitis salivarius agar and much greater than those on MSB. The medium yielded readily recognized S. mutans colonies and facilitated detection of intracellular polysaccharide formers upon flooding with I2 reagent. Freshly isolated serotype c, E, and f colonies could often be distinguished from serotype d and g colonies, a distinction made reliable by testing for intracellular polysaccharide. A study of 300 salivary samples revealed GSTB to give significantly higher recoveries than MSB. About 72% of all samples were substantially underestimated for S. mutans with MSB, and 6.7% of samples were falsely negative for S. mutans with MSB. Recovery of background flora on GSTB was as low or lower than on MSB, and both types of agar could be stored for at least 9 weeks without notable change of selectivity. Thus, GSTB agar appears to be simple and reliable to use and requires no anaerobic incubation. Caution is voiced about

  6. Mars Eolian Geology at Airphoto Scales: The Large Wind Streaks of Western Arabia Terra

    NASA Technical Reports Server (NTRS)

    Edgett, Kenneth S.

    2001-01-01

    More than 27,000 pictures at aerial photograph scales (1.5-12 m/pixel) have been acquired by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) since September 1997. The pictures are valuable for testing hypotheses about geologic history and processes of Mars. Of particular interest are eolian features connected to surface albedo patterns. This work is focused on low-albedo wind streaks, some over 100 km long, in western Arabia Terra. Each streak is widest where it originates at an impact crater (typically 25-150 km diameter). The streaks taper downwind. Within the associated craters there is a lower-albedo surface that, in nearly all observed cases, includes barchan dunes indicative of transport in the same direction as the wind streaks. Upwind of the dunes there is usually an outcrop of layered material that might have served as a source for dune sand. MOC images show that the west Arabia streaks consist of a smooth-surfaced, multiple-meters-thick, mantle (smooth at 1.5 m/pixel) that appears to be superposed on local surfaces. No dunes are present, indicating that down-streak transport of sediment via saltation and traction have not occurred. Two models might explain the observed properties: (1) the streaks consist of dark silt- and clay-sized grains deflated from the adjacent crater interiors and deposited from suspension or (2) they are remnants (protected in the lee of impact crater rims) of a formerly much larger, regional covering of low albedo, smooth-surfaced mantle. The latter hypothesis is based on observation of low albedo mantled surfaces occurring south of west Arabia in Terra Meridiani. For reasons yet unknown, a large fraction of the martian equatorial regions are covered by low albedo, mesa-forming material that lies unconformably atop eroded layered and cratered terrain. Both hypotheses are being explored via continued selective targeting of new MOC images as well as analyses of the new data.

  7. Dust Devils Seen Streaking Across Mars: PART 1--What Are These?

    NASA Technical Reports Server (NTRS)

    2000-01-01

    PIA02376 [figure removed for brevity, see original site]

    PIA02377 [figure removed for brevity, see original site]

    Dark streaks, everywhere! Many Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images of the middle latitudes of the northern and southern hemispheres of Mars show wild patterns of criss-crossing dark streaks. Many of these streaks are straight and narrow, others exhibit curly arcs, twists, and loops. They often cross over hills, run straight across dunes and ripples, and go through fields of house-sized boulders. The two examples shown above were acquired in the last three months. Both pictures are illuminated by sunlight from the upper left. The first picture (left), showing dark streaks on the rippled flats of Argyre Planitia, covers an area 3 km by 5 km (1.9 by 3.1 miles) at a latitude of 51oS. The second picture (right) shows an area approximately 3 km by 5 km in Promethei Terra at a latitude of 58oS.

    For many months the MOC science team was seeing streaks such as these, but were uncertain how they formed. One speculation was that they might result from the passage of dust devils. Each dust devil would leave a dark streak by removing bright dust from the terrain in its path, revealing a darker surface underneath. An image described by the MOC team in July 1998 showed examples of streaks that were, at the time, speculated to be caused by dust devils.

  8. Pulsed photothermal temperature profiling of agar tissue phantoms.

    PubMed

    Milanic, Matija; Majaron, Boris; Nelson, J Stuart

    2007-11-01

    We determine experimentally the accuracy of pulsed photothermal radiometric (PPTR) temperature depth profiling in water-based samples. We use custom tissue phantoms composed of agar gel layers separated by very thin absorbing layers. Two configurations of the acquisition system are compared, one using the customary spectral band of the InSb radiation detector (3.0-5.5 microm) and the other with a spectrally narrowed acquisition band (4.5-5.5 microm). The laser-induced temperature depth profiles are reconstructed from measured radiometric signals using a custom minimization algorithm. The results correlate very well with phantom geometry as determined by optical coherence tomography (OCT) and histology in all evaluated samples. Determination of the absorbing layer depth shows good repeatability with spatial resolution decreasing with depth. Spectral filtering improves the accuracy and resolution, especially for shallow absorption layers (~120 microm) and more complex structures (e.g., with two absorbing layers). The average full width at half maximum (FWHM) of the temperature peaks equals 23% of the layer depth. PMID:17522951

  9. The sedimentology and dynamics of crater-affiliated wind streaks in western Arabia Terra, Mars and Patagonia, Argentina

    USGS Publications Warehouse

    Rodriguez, J.A.P.; Tanaka, K.L.; Yamamoto, A.; Berman, D.C.; Zimbelman, J.R.; Kargel, J.S.; Sasaki, S.; Jinguo, Y.; Miyamoto, H.

    2010-01-01

    Wind streaks comprise recent aeolian deposits that have been extensively documented on Venus, Earth and Mars. Martian wind streaks are among the most abundant surface features on the planet and commonly extend from the downwind margins of impact craters. Previous studies of wind streaks emerging from crater interior deposits suggested that the mode of emplacement was primarily related to the deposition of silt-sized particles as these settled from plumes. We have performed geologic investigations of two wind streaks clusters; one situated in western Arabia Terra, a region in the northern hemisphere of Mars, and another in an analogous terrestrial site located in southern Patagonia, Argentina, where occurrences of wind streaks emanate from playas within maar craters. In both these regions we have identified bedforms in sedimentary deposits on crater floors, along wind-facing interior crater margins, and along wind streaks. These observations indicate that these deposits contain sand-sized particles and that sediment migration has occurred via saltation from crater interior deposits to wind streaks. In Arabia Terra and in Patagonia wind streaks initiate from crater floors that contain lithic and evaporitic sedimentary deposits, suggesting that the composition of wind streak source materials has played an important role in development. Spatial and topographic analyses suggest that regional clustering of wind streaks in the studied regions directly correlates to the areal density of craters with interior deposits, the degree of proximity of these deposits, and the craters' rim-to-floor depths. In addition, some (but not all) wind streaks within the studied clusters have propagated at comparable yearly (Earth years) rates. Extensive saltation is inferred to have been involved in its propagation based on the studied terrestrial wind streak that shows ripples and dunes on its surface and the Martian counterpart changes orientation toward the downslope direction where it

  10. Physicochemical and morphological properties of plasticized poly(vinyl alcohol)-agar biodegradable films.

    PubMed

    Madera-Santana, T J; Freile-Pelegrín, Y; Azamar-Barrios, J A

    2014-08-01

    The effects of the addition of glycerol (GLY) on the physicochemical and morphological properties of poly(vinyl alcohol) (PVA)-agar films were reported. PVA-agar films were prepared by solution cast method, and the addition of GLY in PVA-agar films altered the optical properties, resulting in a decrease in opacity values and in the color difference (ΔE) of the films. Structural characterization using Fourier transformation infrared (FTIR) spectroscopy and X-ray diffraction (XRD) indicated that the presence of GLY altered the intensity of the bands (from 1200 to 800cm(-1)) and crystallinity. The characterization of the thermal properties indicated that an increase in the agar content produces a decrease in the melting temperature and augments the heat of fusion. Similar tendencies were observed in plasticized films, but at different magnification. The formulation that demonstrated the lowest mechanical properties contained 25wt.% agar, whereas the formulation that contained 75wt.% agar demonstrated a significant improvement. The water vapor transmission rate (WVTR) and surface morphology analysis demonstrated that the structure of PVA-agar films is reorganized upon GLY addition. The physicochemical properties of PVA-agar films using GLY as a plasticizer provide information for the application of this formulation as packaging material for specific food applications. PMID:24875313

  11. Electrospinning of agar/PVA aqueous solutions and its relation with rheological properties.

    PubMed

    Sousa, Ana M M; Souza, Hiléia K S; Uknalis, Joseph; Liu, Shih-Chuan; Gonçalves, Maria P; Liu, LinShu

    2015-01-22

    In this work, we report the successful fabrication of agar-based nanofibers by electrospinning technique, using water as solvent media. A tubeless spinneret was attached inside the electrospinning chamber, operating at 50°C, to avoid agar gelation. Agar pure solution (1 wt%) showed inadequate spinnability regardless of the used electrospinning conditions. The addition of a co-blending polymer such as PVA (10 wt% starting solution) improved the solutions viscoelasticity and hence, the solutions spinnability. Agar/PVA solutions were prepared with different mass ratios (100/0, 50/50, 40/60, 30/70, 20/80 and 0/100) and electrospun at various sets of electrospinning conditions. Best nanofibers were obtained with 30/70 and 20/80 agar/PVA blends while samples with higher agar contents (50/50 and 40/60 agar/PVA) were harder to process and led to discontinuous fibrous mats. This first set of encouraging results can open a new window of opportunities for agar-based biomaterials in the form of nanofibers. PMID:25439904

  12. Inhibition of Streptococcus mutans strains by different mitis-salivarius agar preparations.

    PubMed Central

    Staat, R H

    1976-01-01

    Several Streptococcus mutans strains were markedly inhibited by mitis-salivarius agar manufactured by Baltimore Biological Laboratories, but little, if any, inhibition was noted using Difco Laboratories' mitis-salivarius agar. Supplementation of the basic medium with sucrose and bacitracin for specific selection of S. mutans resulted in suppression of representative S. mutans type a strains regardless of manufacturer. PMID:1270597

  13. Effects of season on the yield and quality of agar from Gracilaria species (Gracilariaceae, Rhodophyta).

    PubMed

    Marinho-Soriano, E; Bourret, E

    2003-12-01

    The effect of season on yield and physical properties of agars extracted from Gracia gracilis and G. bursa-pastoris were determined. The agar yield from G. gracilis was maximum during spring (30%) and minimum during autumn (19%). In G. bursa-pastoris, the agar yield was greatest in summer (36%) and lowest in winter (23%). Agar yield from G. bursa-pastoris was positively correlated with temperature (r=0.94; P<0.01) and salinity (r=0.97; P<0.01) and negatively with nitrogen content (r=-0.93; P<0.01). Agar gel strengths fluctuated from 229 to 828 gcm(-2) and 23 to 168 gcm(-2) for G. gracilis and G. bursa-pastoris, respectively. The gelling temperature showed significant seasonal variation for both species. Chemical analysis of agar from the two seaweeds indicated variation in 3,6-anhydrogalactose and sulfate content (P<0.01). Furthermore, there was an inverse correlation between the two chemical variables. In general, agar extracted from G. gracilis possessed better qualities than agar extracted from G. bursa-pastoris and can be considered a candidate for industrial use. PMID:14575957

  14. Agar composition affects in vitro screening of biocontrol activity of antagonistic microorganisms.

    PubMed

    Bosmans, L; De Bruijn, I; De Mot, R; Rediers, H; Lievens, B

    2016-08-01

    Agar-based screening assays are the method of choice when evaluating antagonistic potential of bacterial biocontrol-candidates against pathogens. We showed that when using the same medium, but different agar compositions, the activity of a bacterial antagonist against Agrobacterium was strongly affected. Consequently, results from in vitro screenings should be interpreted cautiously. PMID:27166668

  15. Characteristics of thermoplastic sugar palm Starch/Agar blend: Thermal, tensile, and physical properties.

    PubMed

    Jumaidin, R; Sapuan, S M; Jawaid, M; Ishak, M R; Sahari, J

    2016-08-01

    The aim of this work is to study the behavior of biodegradable sugar palm starch (SPS) based thermoplastic containing agar in the range of 10-40wt%. The thermoplastics were melt-mixed and then hot pressed at 140°C for 10min. SEM investigation showed good miscibility between SPS and agar. FT-IR analysis confirmed that SPS and agar were compatible and inter-molecular hydrogen bonds existed between them. Incorporation of agar increased the thermoplastic starch tensile properties (Young's modulus and tensile strength). The thermal stability and moisture uptake increased with increasing agar content. The present work shows that starch-based thermoplastics with 30wt% agar content have the highest tensile strength. Higher content of agar (40wt%) resulted to more rough cleavage fracture and slight decrease in the tensile strength. In conclusion, the addition of agar improved the thermal and tensile properties of thermoplastic SPS which widened the potential application of this eco-friendly material. The most promising applications for this eco-friendly material are short-life products such as packaging, container, tray, etc. PMID:27177458

  16. Efficacy of agar-plate culture in detection of Strongyloides stercoralis infection.

    PubMed

    Arakaki, T; Iwanaga, M; Kinjo, F; Saito, A; Asato, R; Ikeshiro, T

    1990-06-01

    Agar-plate culture of feces using a modified petri dish proved to be highly efficient in the detection of Strongyloides stercoralis infection. Furrows left by S. stercoralis on the agar plate were distinguished readily in size from those left by Necator americanus. PMID:2352073

  17. Ets2-dependent trophoblast signalling is required for gastrulation progression after primitive streak initiation.

    PubMed

    Polydorou, Christiana; Georgiades, Pantelis

    2013-01-01

    Although extraembryonic ectoderm trophoblast signals the embryo for primitive streak initiation, a prerequisite for gastrulation, it is unknown whether it also signals for the progression of gastrulation after primitive streak initiation. Here, using Ets2-/- mice, we show that trophoblast signalling is also required in vivo for primitive streak elongation, completion of intraembryonic mesoderm epithelial-mesenchymal transition and the development of anterior primitive streak derivatives such as the node. We show that Ets2-dependent trophoblast signalling is required for the maintenance of high levels of Nodal and Wnt3 expression in the epiblast and for the induction of Snail expression in the primitive streak, between embryonic day 6.3 and 6.7. Within extraembryonic ectoderm trophoblast, Ets2 maintains the expression of the transcription factors Elf5, Cdx2 and Eomes, and that of the signalling molecule Bmp4. We propose a model that provides a genetic explanation as to how Ets2 in trophoblast mediates the progression of gastrulation within the epiblast. PMID:23552073

  18. [Evaluation of a new medium, eggplant (Solanum melongena) agar as a screening medium for Cryptococcus neoformans in environmental samples].

    PubMed

    Sengul, Mustafa; Ergin, Cağrı; Kartal, Tuğba

    2014-04-01

    Cryptococcus neofomans is an encapsulated yeast-like fungus that causes life-threatening infections, especially in immunosuppresive patients. C.neoformans infection is believed to be acquired via inhalation of aerosolized particles from the environment. Avian guano, decaying tree hollows and soil are the related known environmental niches. Brown pigmented yeast growth from the precursors in growth media is an important step for the identification and isolation of C.neoformans. Seeds of plants in nature are preferred owing to easy accessibility and low costs for the preparation of such media. Guizotia abysinicca (Niger seed) as Staib agar, Helianthus annus (Sunflower) as Pal's medium, Brassica nigra (Mustard) agar, tobacco agar, Mucuna pruriens (Velvet bean) seed agar, Perilla frutescens (Beefsteak plant) seed agar, Rubus fruticosus (Blackberry) agar and ground red hot pepper agar are pigment-based selective media for the differentiation of C.neoformans. The aim of this study was to observe the pigment production of C.neoformans in a new medium based on eggplant (Solanum melongena) and also to compare its performance with the simplified Staib, Pal's and tobacco agar for isolation from the environment. Three different eggplant-based medium (S.melongena Melanzaza viserba, S.melongena Pinstripe F1 and S.ovigerum Ivory F1) were included in the study. Pigment-forming eggplant medium, simplified Staib agar, Pal's agar and tobacco agar were used for the cultivation of the environmental swabbed samples from 19 Eucalyptus camaldulensis trunk hollows in continuous colonization region. While pigment formation were observed with S.melongena Melanzaza viserba and S.melongena Pinstripe F1 containing media, S.ovigerum Ivory F1 medium was found to be non-reactive. In colonization area (Gökova-Akyaka, Turkey), 11 (57.9%) out of 19 E.camaldulensis samples were positive with simplified Staib agar, Pal's agar and eggplant agar while 10 (52.6%) of them are positive with tobacco agar. C

  19. Adsorptive removal of methylene blue by agar: effects of NaCl and ethanol

    PubMed Central

    2012-01-01

    Adsorption of methylene blue (MB) on agar was investigated as a function of temperature (308-328 K), different concentrations of NaCl and HCl and various weight percentages of binary mixtures of ethanol with water. It was observed that the maximum experimental adsorption capacity, qm, exp, in water is up to 50 mg g-1 and decreases with increase in weight percentage of ethanol and NaCl and HCl concentration compared to that of water. Analysis of data using ARIAN model showed that MB adsorbs as monomer and dimer on the surface of agar. Binding constants of MB to agar were calculated using the Temkin isotherm. The process is exothermic in water and other solutions. The mean adsorption energy (E) value indicated binding of MB to agar is chemical adsorption. Kinetics of this interaction obeys from the pseudo-second-order model and diffusion of the MB molecules into the agar is the main rate-controlling step. PMID:22339759

  20. Intravitreal ranibizumab for bilateral choroidal neovascularisation in a patient with angioid streaks

    PubMed Central

    Yilmaz, Ihsan; Ozkaya, Abdullah; Alkin, Zeynep; Yazici, Ahmet Taylan

    2014-01-01

    Angioid streaks are described as irregular lines deep into the retina, configured in a radiating fashion which results from breaks in Bruch’s membrane. Optic nerve head drusen are acellular, globular deposits located within the optic nerve head. Angioid streaks and optic nerve head drusen may coexist in patients with pseudoxanthoma elasticum. Both disorders may cause choroidal neovascularisation. In this case report we aimed to present a 48-year-old man with pseudoxanthoma elasticum. The patient had bilateral choroidal neovascularisation secondary to angioid streaks and was treated with intravitreal ranibizumab injections. Visual acuity was increased and maintained at the same level during the follow-up time. There was no complication related to the injection. PMID:25073527

  1. Effects of diabatic heating on the ageostrophic circulation of an upper tropospheric jet streak

    NASA Technical Reports Server (NTRS)

    Keyser, D. A.; Johnson, D. R.

    1984-01-01

    Higher temporal resolution data from NASA's fourth Atmospheric Variability Experiment (April 24-25, 1975) are used to study the role of diabatic heating within the convective region in altering the ageostrophic mass circulation in the entrance region of the jet streak. The modifying effect this diabatic heating in the mesoscale storm exerts on the synoptic-scale environmental flow through dynamical mechanisms which link the mass circulation of these two scales is examined. The effect of diabatic heating on the ageostrophic motion within the thermally direct circulation of the jet streak and the mesoscale convective complexes is investigated. Diabatic modes of ageostrophic motion that intensify the upper tropospheric jet streak downstream are identified.

  2. Critical evaluation of attosecond time delays retrieved from photoelectron streaking measurements

    NASA Astrophysics Data System (ADS)

    Wei, Hui; Morishita, Toru; Lin, C. D.

    2016-05-01

    A photoelectron streaking experiment which was conceived as a means to extract the electron wave packet of single-photon ionization has also been employed to retrieve time delays in the fundamental photoemission processes. The discrepancies between the time delays thus measured and those from many sophisticated theoretical calculations have generated a great deal of controversy in recent years. Here we present a careful examination of the methods that were used to retrieve the time delays and demonstrate the difficulty of achieving an accuracy of the retrieved time delays of a few to tens of attoseconds in typical streaking measurements. The difficulty owes more to the lower sensitivity of the streaking spectra to the phase of the photoionization transition dipole than to the spectral phase of the attosecond light pulse in the experiment. The retrieved time delay contains extra errors when the attochirp of the attosecond pulse is large so that the dipole phase becomes negligible compared to it.

  3. Impact of laser phase and amplitude noises on streak camera temporal resolution

    SciTech Connect

    Wlotzko, V.; Uhring, W.; Summ, P.

    2015-09-15

    Streak cameras are now reaching sub-picosecond temporal resolution. In cumulative acquisition mode, this resolution does not entirely rely on the electronic or the vacuum tube performances but also on the light source characteristics. The light source, usually an actively mode-locked laser, is affected by phase and amplitude noises. In this paper, the theoretical effects of such noises on the synchronization of the streak system are studied in synchroscan and triggered modes. More precisely, the contribution of band-pass filters, delays, and time walk is ascertained. Methods to compute the resulting synchronization jitter are depicted. The results are verified by measurement with a streak camera combined with a Ti:Al{sub 2}O{sub 3} solid state laser oscillator and also a fiber oscillator.

  4. Unsteady hot streak simulation through a 1-1/2 stage turbine engine

    NASA Astrophysics Data System (ADS)

    Takahashi, R. K.; Ni, R. H.

    1991-06-01

    The temperature redistribution process in a 1-1/2 stage turbine (consisting of a first stator, first rotor, and second stator) was analyzed using an unsteady 3D Euler flow solver. The study concentrated on tracking a hot streak from the inlet of the first stator to the exit of the second stator. The redistribution of the hot streak in the second stator passage was very different from that in the rotor passage, with no signs of temperature segregation in the second stator passage, and with rotor-generated vortices which persist through the second stator passage and partake in redistributing the remains of the hot streak. The unsteady code predicts different time-averaged temperatures and secondary flow in the second stator passage than in the steady multistage code, although the steady code may be sufficient for predicting time-averaged pressure loadings on both rotor and second stator airfoils, and time-averaged secondary flow vortices in the rotor passage.

  5. Imaging plasmonic fields near gold nanospheres in attosecond time-resolved streaked photoelectron spectra

    NASA Astrophysics Data System (ADS)

    Li, Jianxiong; Thumm, Uwe

    2016-05-01

    To study time-resolved photoemission from gold nanospheres, we introduce a quantum-mechanical approach, including the plasmonic near-field-enhancement of the streaking field at the surface of the nanosphere. We use Mie theory to calculate the plasmonically enhanced fields near 10 to 200 nm gold nanospheres, driven by incident near infrared (NIR) or visible laser pulses. We model the gold conduction band in terms of a spherical square well potential. Our simulated streaked photoelectron spectra reveal a plasmonic amplitude enhancement and phase shift related to calculations that exclude the induced plasmonic field. The phase shift is due to the plasma resonance. This suggests the use of streaked photoelectron spectroscopy for imaging the dielectric response and plasmonic field near nanoparticles. Supported by the NSD-EPSCoR program, NSF, and the USDoE.

  6. Absolute calibration method for fast-streaked, fiber optic light collection, spectroscopy systems.

    SciTech Connect

    Johnston, Mark D.; Frogget, Brent; Oliver, Bryan Velten; Maron, Yitzhak; Droemer, Darryl W.; Crain, Marlon D.

    2010-04-01

    This report outlines a convenient method to calibrate fast (<1ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such a system is used to collect spectral data on plasmas generated in the A-K gap of electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA). On RITS, light is collected through a small diameter (200 micron) optical fiber and recorded on a fast streak camera at the output of 1 meter Czerny-Turner monochromator (F/7 optics). To calibrate such a system, it is necessary to efficiently couple light from a spectral lamp into a 200 micron diameter fiber, split it into its spectral components, with 10 Angstroms or less resolution, and record it on a streak camera with 1ns or less temporal resolution.

  7. Performances of a solid streak camera based on conventional CCD with nanosecond time resolution

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Bai, Yonglin; Zhu, Bingli; Gou, Yongsheng; Xu, Peng; Bai, XiaoHong; Liu, Baiyu; Qin, Junjun

    2015-02-01

    Imaging systems with high temporal resolution are needed to study rapid physical phenomena ranging from shock waves, including extracorporeal shock waves used for surgery, to diagnostics of laser fusion and fuel injection in internal combustion engines. However, conventional streak cameras use a vacuum tube making thus fragile, cumbersome and expensive. Here we report an CMOS streak camera project consists in reproducing completely this streak camera functionality with a single CMOS chip. By changing the mode of charge transfer of CMOS image sensor, fast photoelectric diagnostics of single point with linear CMOS and high-speed line scanning with array CMOS sensor can be achieved respectively. A fast photoelectric diagnostics system has been designed and fabricated to investigate the feasibility of this method. Finally, the dynamic operation of the sensors is exposed. Measurements show a sample time of 500 ps and a time resolution better than 2 ns.

  8. Cassava brown streak disease: a threat to food security in Africa.

    PubMed

    Patil, Basavaprabhu L; Legg, James P; Kanju, Edward; Fauquet, Claude M

    2015-05-01

    Cassava brown streak disease (CBSD) has emerged as the most important viral disease of cassava (Manihot esculenta) in Africa and is a major threat to food security. CBSD is caused by two distinct species of ipomoviruses, Cassava brown streak virus and Ugandan cassava brown streak virus, belonging to the family Potyviridae. Previously, CBSD was reported only from the coastal lowlands of East Africa, but recently it has begun to spread as an epidemic throughout the Great Lakes region of East and Central Africa. This new spread represents a major threat to the cassava-growing regions of West Africa. CBSD-resistant cassava cultivars are being developed through breeding, and transgenic RNA interference-derived field resistance to CBSD has also been demonstrated. This review aims to provide a summary of the most important studies on the aetiology, epidemiology and control of CBSD and to highlight key research areas that need prioritization. PMID:26015320

  9. Development of a multiplexed PCR detection method for Barley and Cereal Yellow Dwarf Viruses, Wheat Spindle Streak Virus, Wheat Streak Mosaic Virus and Soil-Borne Wheat Mosaic Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Barley and Cereal Yellow Dwarf Viruses (B/CYDVs), Wheat Spindle Streak Mosaic (WSSMV), Soil-Borne Wheat Mosaic (SBWMV) Mosaic Virus and Wheat Streak Mosaic Virus (WSMV) constitute the most economically important group of wheat viruses. In this paper, a multiplex reverse transcription polymerase chai...

  10. System for photometric calibration of optoelectronic imaging devices especially streak cameras

    DOEpatents

    Boni, Robert; Jaanimagi, Paul

    2003-11-04

    A system for the photometric calibration of streak cameras and similar imaging devices provides a precise knowledge of the camera's flat-field response as well as a mapping of the geometric distortions. The system provides the flat-field response, representing the spatial variations in the sensitivity of the recorded output, with a signal-to-noise ratio (SNR) greater than can be achieved in a single submicrosecond streak record. The measurement of the flat-field response is carried out by illuminating the input slit of the streak camera with a signal that is uniform in space and constant in time. This signal is generated by passing a continuous wave source through an optical homogenizer made up of a light pipe or pipes in which the illumination typically makes several bounces before exiting as a spatially uniform source field. The rectangular cross-section of the homogenizer is matched to the usable photocathode area of the streak tube. The flat-field data set is obtained by using a slow streak ramp that may have a period from one millisecond (ms) to ten seconds (s), but may be nominally one second in duration. The system also provides a mapping of the geometric distortions, by spatially and temporarily modulating the output of the homogenizer and obtaining a data set using the slow streak ramps. All data sets are acquired using a CCD camera and stored on a computer, which is used to calculate all relevant corrections to the signal data sets. The signal and flat-field data sets are both corrected for geometric distortions prior to applying the flat-field correction. Absolute photometric calibration is obtained by measuring the output fluence of the homogenizer with a "standard-traceable" meter and relating that to the CCD pixel values for a self-corrected flat-field data set.

  11. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    SciTech Connect

    Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H.J.; Greaves, M.; Weber, C.P.; Falcone, R.W.; Padmore, H. A.; Heimann, P.A.

    2010-02-18

    An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.

  12. Linear stability of optimal streaks in the log-layer of turbulent channel flows

    NASA Astrophysics Data System (ADS)

    Alizard, Frédéric

    2015-10-01

    The importance of secondary instability of streaks for the generation of vortical structures attached to the wall in the logarithmic region of turbulent channels is studied. The streaks and their linear instability are computed by solving equations associated with the organized motion that include an eddy-viscosity modeling the effect of incoherent fluctuations. Three friction Reynolds numbers, Reτ = 2000, 3000, and 5000, are investigated. For all flow cases, optimal streamwise vortices (i.e., having the highest potential for linear transient energy amplification) are used as initial conditions. Due to the lift-up mechanism, these optimal perturbations lead to the nonlinear growth of streaks. Based on a Floquet theory along the spanwise direction, we observe the onset of streak secondary instability for a wide range of spanwise wavelengths when the streak amplitude exceeds a critical value. Under neutral conditions, it is shown that streak instability modes have their energy mainly concentrated in the overlap layer and propagate with a phase velocity equal to the mean streamwise velocity of the log-layer. These neutral log-layer modes exhibit a sinuous pattern and have characteristic sizes that are proportional to the wall distance in both streamwise and spanwise directions, in agreement with the Townsend's attached eddy hypothesis (A. Townsend, the structure of turbulent shear flow, Cambridge university press, 1976 2nd edition). In particular, for a distance from the wall varying from y+ ≈ 100 (in wall units) to y ≈ 0.3h, where h is half the height of the channel, the neutral log-layer modes are self-similar with a spanwise width of λz ≈ y/0.3 and a streamwise length of λx ≈ 3λz, independently of the Reynolds number. Based on this observation, it is suggested that compact vortical structures attached to the wall can be ascribed to streak secondary instabilities. In addition, spatial distributions of fluctuating vorticity components show that the onset

  13. Detection of Agar, by Analysis of Sugar Markers, Associated with Bacillus Anthracis Spores, After Culture

    SciTech Connect

    Wunschel, David S.; Colburn, Heather A.; Fox, Alvin; Fox, Karen F.; Harley, William M.; Wahl, Jon H.; Wahl, Karen L.

    2008-08-01

    Detection of small quantities of agar associated with spores of Bacillus anthracis could provide key information regarding its source or growth characteristics. Agar, widely used in growth of bacteria on solid surfaces, consists primarily of repeating polysaccharide units of 3,6-anhydro-L-galactose (AGal) and galactose (Gal) with sulfated and O-methylated galactoses present as minor constituents. Two variants of the alditol acetate procedure were evaluated for detection of potential agar markers associated with spores. The first method employed a reductive hydrolysis step, to stabilize labile anhydrogalactose, by converting to anhydrogalactitol. The second eliminated the reductive hydrolysis step simplifying the procedure. Anhydrogalactitol, derived from agar, was detected using both derivatization methods followed by gas chromatography-mass spectrometry (GC-MS) analysis. However, challenges with artefactual background (reductive hydrolysis) or marker destruction (hydrolysis) lead to the search for alternative sugar markers. A minor agar component, 6-O-methyl galactose (6-O-M gal), was readily detected in agar-grown but not broth-grown bacteria. Detection was optimized by the use of gas chromatography-tandem mass spectrometry (GC-MS-MS). With appropriate choice of sugar marker and analytical procedure, detection of sugar markers for agar has considerable potential in microbial forensics.

  14. Factors Affecting Selectivity of Brilliant Green-Phenol Red Agar for Salmonellae

    PubMed Central

    Moats, W. A.; Kinner, J. A.

    1974-01-01

    Commercial brilliant green (BG)-sulfa agar was found to be nonselective toward a test series of Enterobacteriaceae. Various formulations of BG were prepared by using Trypticase soy agar (BBL) as a base. Results were more reproducible when BG dye was added after sterilization than before. Sulfonamides improved selectivity as compared with brilliant green alone. Sulfanilamide (SN) was slightly more selective for salmonellae than other sulfonamides tested. Bile salts and sodium dodecyl sulfate markedly reduced the toxicity of BG to all the test bacteria. Enterobacter strains were most difficult to inhibit. A combination of 5 mg of BG and 1 g of SN/liter prevented growth of Proteus mirabilis and Escherichia coli and retarded growth of Enterobacter strains. The BG-SN agars were superior in selectivity to a series of commercial agars tested, and numbers of salmonellae recovered on BG-SN agar and Trypticase soy agar (BBL) were the same. Brilliant green agars with various degrees of selectivity are described. PMID:4589120

  15. 78 FR 24199 - Streak Products, Inc. v. UTi, United States, Inc.; Notice of Filing of Complaint and Assignment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... Streak Products, Inc. v. UTi, United States, Inc.; Notice of Filing of Complaint and Assignment Notice is... Products, Inc. (``Streak''), hereinafter ``Complainant,'' against UTi, United States, Inc. (``UTi...). Complainant also alleges that ``UTi engaged in an unfair or unjustly discriminatory practice in violation...

  16. Isotopic streaks suggest a stripy plume under the Marquesas

    NASA Astrophysics Data System (ADS)

    Chauvel, C.; Blais, S.; Maury, R.; Lewin, E.

    2009-12-01

    underlying the southern and the northern islands is the same. We believe that the stripes are mantle plume characteristics. Their presence and persistent occurrence for the 5 Ma of Marquesas volcanism suggest that isotopically distinct mantle sources cohabitate but do not mix at distances less than 100 km. Furthermore, the isotopic range observed at the island scale is also very large, suggesting melting of extremely heterogeneous plume material. To account for all these observations, as well as the geophysical constraints and the age distribution of the islands, we suggest a model like that of Davaille (Nature, 1999) for general plume structures, and Farnetani and Hofmann (EPSL, 2009) for the internal structure of the Hawaiian plume: several small conduits that originated in a single deep mantle plume bring magma to the surface at different locations at the same time. The material melting in the plume is highly heterogeneous at all scales (10 to 100 km) but because systematic trends occur, an organized pattern must persist through time. The inference is that the heterogeneities in the plume were streaked out vertically and parallel to the direction of plume ascent.

  17. Polymer film deposition on agar using a dielectric barrier discharge jet and its bacterial growth inhibition

    NASA Astrophysics Data System (ADS)

    Tsai, T.-C.; Cho, J.; Mcintyre, K.; Jo, Y.-K.; Staack, D.

    2012-08-01

    Polymer film deposition on agar in ambient air was achieved using the helium dielectric barrier discharge jet (DBD jet) fed with polymer precursors, and the bacterial growth inhibition due to the deposited film was observed. The DBD jet with precursor addition was more efficient at sterilization than a helium-only DBD jet. On the areas where polymer films cover the agar the bacterial growth was significantly inhibited. The inhibition efficacy showed dependence on the film thickness. The DBD jet without precursor also created a modified agar layer, which may slow the growth of some bacterial strains.

  18. Modeling of the Bacillus subtilis Bacterial Biofilm Growing on an Agar Substrate.

    PubMed

    Wang, Xiaoling; Wang, Guoqing; Hao, Mudong

    2015-01-01

    Bacterial biofilms are organized communities composed of millions of microorganisms that accumulate on almost any kinds of surfaces. In this paper, a biofilm growth model on an agar substrate is developed based on mass conservation principles, Fick's first law, and Monod's kinetic reaction, by considering nutrient diffusion between biofilm and agar substrate. Our results show biofilm growth evolution characteristics such as biofilm thickness, active biomass, and nutrient concentration in the agar substrate. We quantitatively obtain biofilm growth dependence on different parameters. We provide an alternative mathematical method to describe other kinds of biofilm growth such as multiple bacterial species biofilm and also biofilm growth on various complex substrates. PMID:26355542

  19. Modeling of the Bacillus subtilis Bacterial Biofilm Growing on an Agar Substrate

    PubMed Central

    Wang, Xiaoling; Wang, Guoqing; Hao, Mudong

    2015-01-01

    Bacterial biofilms are organized communities composed of millions of microorganisms that accumulate on almost any kinds of surfaces. In this paper, a biofilm growth model on an agar substrate is developed based on mass conservation principles, Fick's first law, and Monod's kinetic reaction, by considering nutrient diffusion between biofilm and agar substrate. Our results show biofilm growth evolution characteristics such as biofilm thickness, active biomass, and nutrient concentration in the agar substrate. We quantitatively obtain biofilm growth dependence on different parameters. We provide an alternative mathematical method to describe other kinds of biofilm growth such as multiple bacterial species biofilm and also biofilm growth on various complex substrates. PMID:26355542

  20. Numerical analysis of three-dimensional unsteady hot streak migration and shock interaction in a turbine stage

    SciTech Connect

    Saxer, A.P.; Felici, H.M.

    1996-04-01

    A three-dimensional unsteady flow computation has been performed for a transonic first turbine stage under the influence of streaks of hot gas exiting the combustion chamber. Realistic flow conditions are obtained by using an unequal stator-to-rotor pitch, a single-streak/multistator channel configuration, and periodic boundary conditions. The resulting unsteady shock wave system and the hot streak migration as well as the shock wave/streak interaction are presented and discussed. In addition, the time average of the periodic unsteady solution is analyzed and compared with a steady-state computation. The steady-state solution matches the time-averaged one in terms of the pressure field and the maximum stagnation temperature on the rotor blade surface. However, the rotor blade temperature patterns are different with a stronger radial secondary flow present in the time-averaged solution due to the retention of the circumferential streak variations at the stator/rotor interface.

  1. Effect of heat treatment on the performance of tryptose-sulfite-cycloserine agar for enumeration of Clostridium perfringens.

    PubMed

    Brodsky, M H; Ciebin, B W

    1979-05-01

    Dissolving dehydrated tryptose-sulfite-cycloserine agar by only boiling or microwaving was found to inhibit Clostridium perfringens colony development in pour plates when compared with C. perfringens recovery in tryptose-sulfite-cycloserine agar prepared by autoclaving. PMID:225988

  2. Role of wheat streak mosaic virus-encoded proteins in disease development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eriophyid mite-transmitted wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are the type species of Tritimovirus and Poacevirus genera, respectively, in the family Potyviridae. TriMV and WSMV exhibit differential symptom phenotypes on wheat: TriMV elicits mild mosaic and mottling ...

  3. Nuclear import of Maize fine streak virus proteins in Drosophila S2 cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize fine streak virus (MFSV) is a member of the genus Nucleorhabdovirus, family Rhabdoviridae and is transmitted by the leafhopper Graminella nigrifons. The virus replicates in both its plant host and in its insect vector. Nucleorhabdoviruses replicate in the nucleus and assemble at the inner nu...

  4. Plant host range and leafhopper transmission of Maize fine streak virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize fine streak virus (MFSV), an emerging rhabdovirus species in the genus Nucleorhabdovirus, is persistently transmitted by the black-faced leafhopper, Graminella nigrifrons (Forbes). MFSV was transmitted to maize, wheat, oats, rye, barley, foxtail, annual ryegrass and quackgrass by G. nigrifron...

  5. Efficient inoculation of rice black-streaked dwarf virus to maize using Laodelphax striatellus Fallen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize rough dwarf disease (MRDD) caused by Rice black-streaked dwarf virus (RBSDV) is the most important viral disease of maize in China. Although deploying disease resistant hybrids would be the most effective way to control the disease, development of resistant hybrids has been limited by virus t...

  6. Optical Comb Generation for Streak Camera Calibration for Inertial Confinement Fusion Experiments

    SciTech Connect

    Ronald Justin, Terence Davies, Frans Janson, Bruce Marshall, Perry Bell, Daniel Kalantar, Joseph Kimbrough, Stephen Vernon, Oliver Sweningsen

    2008-09-18

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is coming on-line to support physics experimentation for the U.S. Department of Energy (DOE) programs in Inertial Confinement Fusion (ICF) and Stockpile Stewardship (SS). Optical streak cameras are an integral part of the experimental diagnostics instrumentation at NIF. To accurately reduce streak camera data a highly accurate temporal calibration is required. This article describes a technique for simultaneously generating a precise +/- 2 ps optical marker pulse (fiducial reference) and trains of precisely timed, short-duration optical pulses (so-called “comb” pulse trains) that are suitable for the timing calibrations. These optical pulse generators are used with the LLNL optical streak cameras. They are small, portable light sources that, in the comb mode, produce a series of temporally short, uniformly spaced optical pulses, using a laser diode source. Comb generators have been produced with pulse-train repetition rates up to 10 GHz at 780 nm, and somewhat lower frequencies at 664 nm. Individual pulses can be as short as 25-ps FWHM. Signal output is via a fiber-optic connector on the front panel of the generator box. The optical signal is transported from comb generator to streak camera through multi-mode, graded-index optical fiber.

  7. Evaluation of banana hybrids for tolerance to black leaf streak (Mycosphaerella fijiensis Morelet) in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled 133,500 tons in 2008. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and M. musicola, respectively, are responsible for significant los...

  8. Chromatin Structure of Wheat Breeding Lines Resistant to Wheat Streak Mosaic Virus.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat Streak Mosaic Virus (WSMV) is an important disease limiting wheat production, however no WSMV resistance effective above 18°C is present within the primary genetic pool of wheat (Triticum aestivum L.). In contrast, the wild relative Thinopyrum intermedium (2n=6x=42) shows good resistance to WS...

  9. Physiological responses of hard red winter wheat to infection by wheat streak mosaic virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) causes significant yield loss in hard red winter wheat in the U.S. Southern High Plains. Despite the prevalence of this pathogen, little is known about the physiological response of wheat to WSMV infection. A 2-year study was initiated to (i) investigate the effect o...

  10. Economic impact of wheat streak mosaic virus in the Texas High Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV), vectored by the wheat curl mite Aceria tosichella Keifer, is a major limiting factor in wheat production in the Texas Panhandle. It is the most frequently encountered virus in the region, affecting both shoot and root biomass, and consequently it can drastically red...

  11. Multiplex Real Time PCR For Detection of Wheat Streak Mosaic Virus and Triticum Mosaic Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TRIMV) are widespread throughout the southwestern Great Plains states. Using conventional diagnostics such as Enzyme-Linked Immunosorbent Assays (ELISA), these two viruses are commonly found together in infected wheat samples. Methods for m...

  12. Complete genome sequence of an emerging genotype of tobacco streak virus in the U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the complete genome sequence of an emerging genotype of Tobacco streak virus (TSV) infecting zucchini squash in Florida (TSV_FL13-07), through deep sequencing of sRNAs and validation by Sanger sequencing. TSV_FL13-07 only shares less than 90% sequence identity in three genomic ribonucleic...

  13. Pedicle streaking: A novel and simple aid in pedicle positioning in free tissue transfer

    PubMed Central

    Aggarwal, Aditya; Singh, Hardeep; Mahendru, Sanjay; Brajesh, Vimalendu; Singh, Sukhdeep; Khare, Ashish; Kothari, Umang; Khazanchi, Rakesh Kumar

    2015-01-01

    Introduction: The pedicle positioning in free tissue transfer is critical to its success. Long thin pedicles are especially prone to this complication where even a slight twist in the perforator can result in flap loss. Pedicles passing through the long tunnels are similarly at risk. Streaking the pedicle with methylene blue is a simple and safe method which increases the safety of free tissue transfer. Materials and Methods: Once the flap is islanded on the pedicle and the vascularity of the flap is confirmed, the pedicle is streaked with methylene blue dye at a distance of 6-7 mm. The streaking starts from the origin of the vessels and continued distally on to the under surface of flap to mark the complete course of the pedicle in alignment. The presence of streaking in some parts and not in rest indicates twist in the pedicle. Observation and Results: Four hundred and sixty five free flaps have been done at our centre in the last 5 years. The overall success rate of free flaps is 95.3% (22 free flap failures). There has not been a single case of pedicle twist leading to flap congestion and failure. Conclusion: This simple and novel method is very reliable for pedicle positioning avoiding any twist necessary for successful free tissue transfer. PMID:26933280

  14. Simultaneous velocity interferometry and electronic streak photography of laser-launched plates

    SciTech Connect

    Paisley, D.L.; Stahl, D.B.; Garcia, I.A.

    1991-01-01

    Laser-launched, miniature, pseudo-one-dimensional flyer plates are evaluated by three distinct optical techniques that may be incorporated into an optical diagnostic system to give a complete understanding of the plate performance. These techniques are: velocity interferometry, streak photography, and pulsed laser stereo photography. 2 refs., 5 figs.

  15. Standard design for National Ignition Facility x-ray streak and framing cameras.

    PubMed

    Kimbrough, J R; Bell, P M; Bradley, D K; Holder, J P; Kalantar, D K; MacPhee, A G; Telford, S

    2010-10-01

    The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube. PMID:21034058

  16. Diverse soybean accessions identified with temperature-sensitive resistance to Tobacco streak virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tobacco streak virus (TSV) is a pathogen that has been reported in soybean in Brazil and the United States, for which resistance has only been reported in the “hay-type” soybean cultivar Tanner. To find additional resistant soybean genotypes, over 1000 soybean accessions from the USDA Soybean Germpl...

  17. Science Notes: Dilution of a Weak Acid

    ERIC Educational Resources Information Center

    Talbot, Christopher; Wai, Chooi Khee

    2014-01-01

    This "Science note" arose out of practical work involving the dilution of ethanoic acid, the measurement of the pH of the diluted solutions and calculation of the acid dissociation constant, K[subscript a], for each diluted solution. The students expected the calculated values of K[subscript a] to be constant but they found that the…

  18. A fresh liver agar substrate for rearing small numbers of forensically important blow flies (Diptera: Calliphoridae)

    USGS Publications Warehouse

    Gruner, Susan V.; Slone, Daniel H.

    2014-01-01

    Forensically important calliphorids can be reared on a mixture of beef liver and agar. Small pieces of meat, especially fresh or frozen beef liver, will desiccate in 2–6 h, but this simple-to-make feeding substrate remains moist for at least 12 h at 25 and 30°C without desiccation, even in small (5 g) amounts. We determined the survivorship of small numbers of Chrysomya megacephala (F.) (first-instar larvae to adult eclosion) raised on 5 g of liver agar and fresh beef liver. We found that all larvae raised on 5 g of liver died due to desiccation, but survivorship on 5 g of liver agar was equivalent to that on larger (50 g) pieces of either liver agar or beef liver.

  19. [THE APPLICATION OF SELECTIVE CHROMOGENIC AGAR FOR DETECTING ENTEROBACTERIA WITH PRODUCTION OF BETA-LACTAMASES].

    PubMed

    Korobova, A G; Frolova, L N; Kliasova, G A

    2015-11-01

    The detection of enterobacteria with production of beta-lactamases of extended spectrum in selective chromogenic agar was analyzed The results ofdetection of beta-lactamases of extended spectrum was compared with "double disc" technique. The smears from mucous membrane of guttur and rectum from patients were analyzed in parallel on solid growth agar (Endo or Mac Conkey) and on selective agar CHROMagartm ESBL (CHROMagar France). The production of beta-lactamases of extended spectrum was confirmed using "double discs" technique. To exclude hyper-production of ampC beta-lactamases E-test was applied containing cefotetan and cefotetan with cloxacillin. The sampling consisted of 1552 samples from patients. The study permitted to isolate 1243 strains of enterobacteria on agar Endo or Mac Conkey and 409 strains of enterobacteria on selective agar CHROMagartm ESBL (Escherichia coli n = 226, Klebsiella pneumoniae n = 105, enterobacter spp. n = 35, Citrobacter spp. n = 21, others n = 22). The application of "double discs" technique confirmed production of beta-lactamases of extended spectrum in 386 (94%) out of 409 strains isolated on agar CHROMagartm ESBL. In 23 (6%) of strains no confirmation was established and hyper-production of ampC of beta-lactamases was established 15 out of total. Additionally, 8 were sensitive to cephalosporin of third generation. All enterobacteria isolated on agar Endo or Mac Conkey also were tested by "double discs" technique. Overall, 394 strains of enterobacteria with production of beta-lactamases of extended spectrum were obtained. On all agars (agar Endo or Mac Conkey and CHROMagartm ESBL)--263 (67%) strains; only on CHROMagartm ESBL--123 (31%) and only on agar Endo or Mac Conkey--8 (2%) (p < 0.0001). The sensitivity of selective agar CHROMagartm ESBL made up to 98% and specificity--97%. The resolution about detection of enterobacteria producing beta-lactamases of extended spectrum were submitted to clinic in 18-24 hours after arrival

  20. Genome Sequence of the Agar-Degrading Marine Bacterium Alteromonadaceae sp. Strain G7

    PubMed Central

    Kwak, Min-Jung; Song, Ju Yeon; Kim, Byung Kwon; Chi, Won-Jae; Kwon, Soon-Kyeong; Choi, Soobeom; Chang, Yong-Keun

    2012-01-01

    Here, we present the high-quality draft genome sequence of the agar-degrading marine gammaproteobacterium Alteromonadaceae sp. strain G7, which was isolated from coastal seawater to be utilized as a bioresource for production of agar-derived biofuels. The 3.91-Mb genome contains a number of genes encoding algal polysaccharide-degrading enzymes such as agarases and sulfatases. PMID:23209220

  1. Low density, microcellular, dopable, agar/gelatin foams for pulsed power experiments

    SciTech Connect

    McNamara, W.F.; Aubert, J.H.

    1997-04-01

    Low-density, microcellular foams prepared from the natural polymers agar and gelatin have been developed for pulsed-power physics experiments. Numerous experiments were supported with foams having densities at or below 10 mg/cm{sup 3}. For some of the experiments, the agar/gelatin foam was uniformly doped with metallic elements using soluble salts. Depending on the method of preparation, cell sizes were typically below 10 microns and for one process were below 1.0 micron.

  2. Laboratory Simulations and Spectral Analyses of Recurring Slope Streaks on Mars

    NASA Astrophysics Data System (ADS)

    Wing, B.; Irvin, B.; Hibbitts, C.; Mushkin, A.

    2014-12-01

    Low albedo streaks on Martian slopes have been cited as possible evidence for present-day intermittent and repeated surface flow of water, or brine (Mushkin et al., 2010). Also termed as Recurring Slope Lineae (1), such streaks can grow, fade, and recur repeatedly on the same slopes. Although distinguishable by being darker than surrounding terrain slope streaks have no diagnostic spectral absorption features (2). A leading hypothesis is formation by multiple wetting and drying events. Laboratory investigations have previously explored this possibility (e.g 3). When wetted with brines, soils darken, but as the sample dries, it brightens again. Wetting also results in absorption bands near 1.5 and 2 microns, which are not detected in spectra of slope streaks. Additionally, dried brines of most salts such as MgSO4, or other sulfates and many chlorides are brighter than Martian soils. However, iron chlorides are a salt that have lower albedo than most other salts and may present a mechanism for darkening slope streaks without inducing a spectral absorption feature. To explore this hypothesis, we have begun to conduct experiments investigating the spectra of iron chloride chloride solutions wetting palagonite and subsequently drying under Martian atmospheric conditions. Preliminary experiments demonstrate that FeIII chloride dried onto palagonite has no absorption features in the NIR and SWIR and remains dark and red. However, these chlorides will oxidize under terrestrial conditions forming Fe2O3 as they dry. We have constructed an environmental chamber that mimics Martian oxygen fugacity though a combination of vacuum and N2 purging, allowing for sample wetting and drying while concurrently taking spectra from 0.4 to 2.4 microns. Results from this experimental setup under Martian atmospheric conditions will be presented. References: (1) McEwen et al., (2011) Science, 333, 740-743, (2) Mushkin et al., (2010) Geophys. Res. Lett., 37, L22201, doi: 10.1029/2010GL044535

  3. Entrapment of α-Amylase in Agar Beads for Biocatalysis of Macromolecular Substrate

    PubMed Central

    Sharma, Manu; Sharma, Vinay; Majumdar, Dipak K.

    2014-01-01

    Attempts have been made to optimize immobilization parameters, catalytic property, and stability of immobilized α-amylase in agar. The work compares natural entrapment efficiency of agar with the ionotropically cross-linked agar hydrogel, with the advantage of easy scale-up and cost and time effectiveness. Beads prepared with 3% (w/v) agar and 75 mM calcium chloride and hardened for 20 minutes were selected for further studies on the basis of entrapment efficiency (80%) and physical stability. Following entrapment, pH and temperature optima of enzyme were shifted from 6 to 6.5 and 50 to 55°C, respectively. Michaelis constant (Km) for both free and entrapped enzymes remained the same (0.83%) suggesting no change in substrate affinity. However, Vmax⁡ of entrapped enzyme decreased ~37.5-fold. The midpoint of thermal inactivation for entrapped enzyme increased by 8 ± 1°C implying its higher thermal stability. The entrapped enzyme in calcium agar bead had an Ea value of 27.49 kcal/mol compared to 17.6 kcal/mol for free enzyme indicating increased stability on entrapment. Half-life of enzyme increased ~2.2 times after entrapment in calcium agar at 60°C indicating stabilization of enzyme. The reusability of beads was size dependent. Beads with diameter <710 μm were stable and could be reused for 6 cycles with ~22% loss in activity.

  4. Rapid detection of Clostridium perfringens: comparison of lactose sulfite broth with tryptose-sulfite-cycloserine agar.

    PubMed

    Neut, C; Pathak, J; Romond, C; Beerens, H

    1985-01-01

    The lactose sulfite (LS) medium recommended for the detection and identification of Clostridium perfringens in foods was compared with a reference method using tryptose-sulfite-cycloserine (TSC) agar for the enumeration of this organism in a variety of foods and food ingredients. C. perfringens was detected and enumerated in 17 of the 54 samples examined with LS broth, but its presence could be confirmed in only 9 of the samples with TSC agar. In only 2 instances, C. perfringens was detected on TSC agar but not in LS broth. A positive response (FeS + and gas +) in LS broth incubated at 46 degrees C always corresponded to the presence of C. perfringens; whereas the black colonies formed on TSC agar incubated at 37 degrees C were frequently found to be Clostridium species other than C. perfringens. Thus, because of its highly selective nature, LS broth was superior to TSC agar for enumerating and confirming the small numbers of C. perfringens that were present in a majority of the samples. This was especially true when other clostridia were also present. Besides its greater selectivity and sensitivity, LS broth had the additional advantages of requiring less work and giving confirmed results within 24-48 h compared with 3 days for the TSC agar method. PMID:2865247

  5. [GROWTH OF MICROMYCETES FROM DIFFERENT ECOLOGICAL NICHES ON AGAR NUTRIENT MEDIA].

    PubMed

    Kurchenko, I M; Yurieva, E M; Voychuk, S I

    2015-01-01

    Radial growth rate of (K(r)) 153 strains 6 species of micromycetes from different ecological niches was studied on 7 agar media: three standard (malt extract agar, potato-dextrose agar, Czapek's agar), and on agar media with plant polymers (carboxymethylcellulose, xylan, soluble starch and apple pectin). Endophytic and plant pathogenic strains (biotrophs) of all studied species did not differ significantly in their ability to grow on nutrient media of different composition--average values of K(r) for these two groups were the same (0,200 and 0,199 mm/h, respectively). Soil micromycetes (saprophytes) characterized by the lowest average growth rate (0,169 mm/h) and significantly differed from the endophytic and plant pathogenic ones. Average of the radial growth rates of studied microscopic fungi were higher on standard nutrient media than with plant polymers ones. Growth parameters of endophytes and plant pathogens of all studied species on various agar media differed from the soil strains. High growth rate of endophytic and plant pathogenic strains of Fusarium poae, Alternaria alternata and Ceratocystis sp. provides them the rapid colonization of plants. Penicillium funiculosum strains equally can exist as saprophytes in soil and as endophytic plant symbionts. A wide range of K(r) variation of endophytic dark pigmented Mycelia sterilia indicates the presence in this group of different species of micromycetes, which have no sporulation. PMID:26638483

  6. Growth of coagulase-negative staphylococci on colistin-nalidixic acid agar and susceptibility to polymyxins.

    PubMed

    Fung, J C; McKinley, G; Tyburski, M B; Berman, M; Goldstein, J

    1984-05-01

    Colistin-nalidixic acid agar, although recently recommended as a replacement for blood agar for primary plating of urine specimens ( Fung et al., J. Clin. Microbiol. 16:632-636, 1982), has also been reported to suppress the growth of some strains of staphylococci that are susceptible to colistin (polymyxin E). The susceptibility of 11 species of staphylococci to polymyxins was determined, and the ability of these species to grow on colistin-nalidixic acid agar was examined. Although the MICs for most of the strains tested were 8 micrograms/ml or less, only a few coagulase-negative staphylococci grew on or were inhibited by colistin-nalidixic acid agar. This descrepancy was explained by the antagonistic effects that medium components, such as physiological concentrations of magnesium and calcium and 5% sheep blood, had on the activity of polymyxin. Colistin-nalidixic acid agar is still recommended for routine urine processing; however, the poor growth of 13% of the Staphylococcus saprophyticus strains tested suggests that blood agar should be included in the primary plating battery of urine specimens obtained from female outpatients. PMID:6330170

  7. Evaluation of diffusion and dilution methods to determine the antibacterial activity of plant extracts.

    PubMed

    Klancnik, Anja; Piskernik, Sasa; Jersek, Barbara; Mozina, Sonja Smole

    2010-05-01

    The aim of this study was to evaluate diffusion and dilution methods for determining the antibacterial activity of plant extracts and their mixtures. Several methods for measurement of the minimal inhibitory concentration (MIC) of a plant extract are available, but there is no standard procedure as there is for antibiotics. We tested different plant extracts, their mixtures and phenolic acids on selected gram-positive (Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes) and gram-negative bacteria (Escherichia coli O157:H7, Salmonella Infantis, Campylobacter jejuni, Campylobacter coli) with the disk diffusion, agar dilution, broth microdilution and macrodilution methods. The disk diffusion method was appropriate only as a preliminary screening test prior to quantitative MIC determination with dilution methods. A comparison of the results for MIC obtained by agar dilution and broth microdilution was possible only for gram-positive bacteria, and indicated the latter as the most accurate way of assessing the antimicrobial effect. The microdilution method with TTC (2,3,5-triphenyl tetrazolium chloride) or INT (2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride) to indicate the viability of aerobic bacteria was found to be the best alternative approach, while only ATP determination was appropriate for microaerophilic Campylobacter spp. Using survival curves the kinetics of bacterial inactivation on plant extract exposure was followed for 24h and in this way the MIC values determined by the microdilution method were confirmed as the concentrations of extracts that inhibited bacterial growth. We suggest evaluation of the antibacterial activity of plant extracts using the broth microdilution method as a fast screening method for MIC determination and the macrodilution method at selected MIC values to confirm bacterial inactivation. Campylobacter spp. showed a similar sensitivity to plant extracts as the tested gram-positive bacteria, but S

  8. Selective agars for the isolation of Streptococcus iniae from Japanese flounder, Paralichthys olivaceus, and its cultural environment.

    PubMed

    Nguyen, H T; Kanai, K

    1999-05-01

    Two kinds of selective agar were developed for the isolation of Streptococcus iniae, the causal agent of streptococcosis, from Japanese flounder (Paralichthys olivaceus) and from culture tanks in flounder farms. The selective agars were heart infusion agar with added thallium acetate and oxlinic acid (TAOA), and colistin sulphate and oxolinic acid (CSOA). For samples containing various bacterial flora, selective agars were supplemented with defibrinated horse blood in order to distinguish beta-haemolytic colonies of Strep. iniae. Streptococcus iniae was quantitatively isolated from the brain and kidney of diseased flounders in pure culture. Two-thirds of isolates picked up from selective blood agars inoculated with intestinal samples were identified as Strep. iniae. The bacterial colony numbers of deposits and water from culture tanks on selective blood agars were about 10-10(5) times smaller than those on control heart infusion agar; Strep. iniae was isolated from few deposit and water samples. PMID:10347871

  9. Dilute acid and autohydrolysis pretreatment.

    PubMed

    Yang, Bin; Wyman, Charles E

    2009-01-01

    Exposure of cellulosic biomass to temperatures of about 120-210 degrees C can remove most of the hemicellulose and produce cellulose-rich solids from which high glucose yields are possible with cellulase enzymes. Furthermore, the use of dilute sulfuric acid in this pretreatment operation can increase recovery of hemicellulose sugars substantially to about 85-95% of the maximum possible versus only about 65% if no acid is employed. The use of small-diameter tubes makes it possible to employ high solids concentrations similar to those preferred for commercial operations, with rapid heat-up, good temperature control, and accurate closure of material balances. Mixed reactors can be employed to pretreat larger amounts of biomass than possible in such small-diameter tubes, but solids concentrations are limited to about 15% or less to provide uniform temperatures. Pretreatment of large amounts of biomass at high solids concentrations is best carried out using direct steam injection and rapid pressure release, but closure of material balances in such "steam gun" devices is more difficult. Although flow of water alone or containing dilute acid is not practical commercially, such flow-through configurations provide valuable insight into biomass deconstruction kinetics not possible in the batch tubes, mixed reactors, or steam gun systems. PMID:19768619

  10. A Microgravity Helium Dilution Cooler

    NASA Technical Reports Server (NTRS)

    Roach, Pat R.; Sperans, Joel (Technical Monitor)

    1994-01-01

    We are developing a He-3-He-4 dilution cooler to operate in microgravity. It uses charcoal adsorption pumps and heaters for its operation; it has no moving parts. It currently operates cyclically to well below 0.1 K and we have designed a version to operate continuously. We expect that the continuous version will be able to provide the long-duration cooling that many experiments need at temperatures down to 0.040 K. More importantly, such a dilution cooler could provide the precooling that enables the use of adiabatic demagnetization techniques that can reach temperatures below 0.001 K. At temperatures below 0.002 K many fascinating microgravity experiments on superfluid He-3 become possible. Among the possibilities are: research into a superfluid He-3 gyroscope, study of the nucleation of the B-phase of superfluid He-3 when the sample is floating out of contact with walls, study of the anisotropy of the surface tension of the B-phase, and NMR experiments on tiny free-floating clusters of superfluid He-3 atoms that should model the shell structure of nuclei.

  11. Diffusion of Methylene Blue in Phantoms of Agar Using a Photoacoustic Technique

    NASA Astrophysics Data System (ADS)

    Vilca-Quispe, L.; Alvarado-Gil, J. J.; Quintana, P.; Ordonez-Miranda, J.

    2010-05-01

    In this work, the kinetics of diffusion of methylene blue in agar aqueous solution is studied using a photoacoustic technique. Two agar phantoms solutions in water with a relation of mass/volume of 0.01% and 0.05% were analyzed. The study was performed using a modified Rosencwaig photoacoustic cell that is enclosed by transparent windows, on both sides. The sample is deposited directly on top of the upper window. A red light beam, at a fixed modulation frequency, is sent through the lower window illuminating the sample and inducing the photoacoustic effect inside the closed chamber of the cell. At the beginning of the experiment, a droplet of 100μL of agar solution is deposited; afterwards, the signal stabilizes, and 10μL of methylene blue aqueous solution (0.0125 g · mL-1) is added to the surface of the agar. During the first seconds of the experiment, the photoacoustic signal amplitude increases followed by a gradual and long decay. Results for modulation frequencies in the range from 10Hz to 80Hz for both agar concentrations are presented. A simple theoretical approach is presented to analyze the experimental data. It is demonstrated that the kinetics of the process can be parameterized as a function of the changes of an effective optical absorption coefficient. From these results, the characteristic time, in which the dye diffusion process stabilizes, is obtained. It is found that this time is larger for samples with a higher agar concentration. These differences provide important results for biomedical sciences in which agar gels are used as phantoms resembling some of the properties of living organs and tissues.

  12. Mass production of spores of lactic acid-producing Rhizopus oryzae NBRC 5384 on agar plate.

    PubMed

    Yamane, Tsuneo; Tanaka, Ryosuke

    2013-01-01

    Mass production of sporangiospores (spores) of Rhizopus oryzae NBRC 5384 (identical to NRRL 395 and ATCC 9363) on potato-dextrose-agar medium was studied aiming at starting its L(+)-lactic acid fermentation directly from spore inoculation. Various parameters including harvest time, sowed spore density, size of agar plate, height of air space, and incubation mode of plate (agar-on-bottom or agar-on-top) were studied. Ordinarily used shallow Petri dishes were found out to be unsuitable for the full growth of R. oryzae sporangiophores. In a very wide range of the sowed spore density, the smaller it was, the greater the number of the harvested spores was. It was also interesting to find out that R. oryzae grown downward vertically with a deep air space in an agar-on-top mode gave larger amount of spores than in an agar-on-bottom mode at 30°C for 7-day cultivation. Scale-up of the agar plate culture from 26.4 to 292 cm(2) was studied, resulting in the proportional relationship between the number of the harvested spores/plate and the plate area in the deep Petri dishes. The number of plates of 50 cm in diameter needed for 100 m(3) industrial submerged fermentation started directly from 2 × 10(5) spores/mL inoculum size was estimated as about 6, from which it was inferred that such a fermentation would be feasible. Designing a 50 cm plate and a method of spreading and collecting the spores were suggested. Bioprocess technological significance of the "full-scale industrial submerged fermentation started directly from spore inoculation omitting pre-culture" has been discussed. PMID:23658025

  13. Evaluation of CP Chromo Select Agar for the enumeration of Clostridium perfringens from water.

    PubMed

    Manafi, Mammad; Waldherr, Kerstin; Kundi, Michael

    2013-10-01

    The European Directive on drinking water quality has included mCP agar as the reference method for recovering Clostridium perfringens from drinking waters. In the present study, three media (mCP, TSCF and CP Chromo Select Agar) were evaluated for recovery of C. perfringens in different surface water samples. Out of 139 water samples, using a membrane filtration technique, 131 samples (94.2%) were found to be presumptively positive for C. perfringens in at least one of the culture media. Green colored colonies on CP Chromo Select Agar (CCP agar) were counted as presumptive C. perfringens isolates. Out of 483 green colonies on CCP agar, 96.3% (465 strains, indole negative) were identified as C. perfringens, and 15 strains (3.1%) were indole positive and were identified as Clostridium sordellii, Clostridium bifermentans or Clostridium tetani. Only 3 strains (0.6%) gave false positive results and were identified as Clostridium fallax, Clostridium botulinum, and Clostridium tertium. Variance analysis of the data obtained shows statistically no significant differences in the counts obtained between media employed in this work. The mCP method is very onerous for routine screening and bacterial colonies could not be used for further biochemical testing. The colonies on CCP and TSCF were easy to count and subculture for confirmation tests. TSCF detects sulfite-reducing clostridia, including species other than C. perfringens, and in some cases excessive blackening of the agar frustrated counting of the colonies. If the contamination was too high, TSCF did not consistently produce black colonies and as a consequence, the colonies were white and gave false negative results. On the other hand, the identification of typical and atypical colonies isolated from all media demonstrated that CCP agar was the most useful medium for C. perfringens recovery in water samples. PMID:23816139

  14. Preparation and characterization of bio-nanocomposite films of agar and silver nanoparticles: laser ablation method.

    PubMed

    Rhim, Jong-Whan; Wang, Long-Feng; Lee, Yonghoon; Hong, Seok-In

    2014-03-15

    Silver nanoparticles (AgNPs) were prepared by a laser ablation method and composite films with the AgNPs and agar were prepared by solvent casting method. UV-vis absorbance test and transmission electron microscopy (TEM) analysis results revealed that non-agglomerated spherical AgNPs were formed by the laser ablation method. The surface color of the resulting agar/AgNPs films exhibited the characteristic plasmonic effect of the AgNPs with the maximum absorption peaks of 400-407 nm. X-ray diffraction (XRD) test results also exhibited characteristic AgNPs crystals with diffraction peaks observed at 2θ values of 38.39°, 44.49°, and 64.45°, which were corresponding to (111), (200), and (220) crystallographic planes of face-centered cubic (fcc) silver crystals, respectively. Thermogravimetric analysis (TGA) results showed that thermal stability of the agar/AgNPs composite films was increased by the inclusion of metallic silver. Water vapor barrier properties and surface hydrophobicity of the agar/AgNPs films increased slightly with the increase in AgNPs content but they were not statistically significant (p>0.05), while mechanical strength and stiffness of the composite films decreased slightly (p<0.05). The agar/AgNPs films exhibited distinctive antimicrobial activity against both Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli O157:H7) bacterial pathogens. PMID:24528754

  15. Antimicrobial and physical-mechanical properties of agar-based films incorporated with grapefruit seed extract.

    PubMed

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-02-15

    The use of synthetic petroleum based packaging films caused serious environmental problems due to their difficulty in recycling and poor biodegradability. Therefore, present study was aimed to develop natural biopolymer-based antimicrobial packaging films as an alternative for the synthetic packaging films. As a natural antimicrobial agent, grapefruit seed extract (GSE) has been incorporated into agar to prepare antimicrobial packaging film. The films with different concentrations of GSE were prepared by a solvent casting method and the resulting composite films were examined physically and mechanically. In addition, the films were characterized by FE-SEM, XRD, FT-IR and TGA. The incorporation of GSE caused increase in color, UV barrier, moisture content, water solubility and water vapor permeability, while decrease in surface hydrophobicity, tensile strength and elastic modulus of the films. As the concentration of GSE increased from 0.6 to 13.3 μg/mL, the physical and mechanical properties of the films were affected significantly. The addition of GSE changed film microstructure of the film, but did not influence the crystallinity of agar and thermal stability of the agar-based films. The agar/GSE films exhibited distinctive antimicrobial activity against three test food pathogens, such as Listeria monocytogenes, Bacillus cereus and Escherichia coli. These results suggest that agar/GSE films have potential to be used in an active food packaging systems for maintaining food safety and extending the shelf-life of the packaged food. PMID:24507339

  16. Characterization of bionanocomposite films prepared with agar and paper-mulberry pulp nanocellulose.

    PubMed

    Reddy, Jeevan Prasad; Rhim, Jong-Whan

    2014-09-22

    Crystallized nanocellulose (CNC) was separated from paper-mulberry (Broussonetia kazinoki Siebold) bast pulp by sulfuric acid hydrolysis method and they were blended with agar to prepare bionanocomposite films. The effect of CNC content (1, 3, 5 and 10 wt% based on agar) on the mechanical, water vapor permeability (WVP), and thermal properties of the nanocomposites were studied. Changes of the cellulose fibers in structure, morphology, crystallinity, and thermal properties of the films were evaluated using FT-IR, TEM, SEM, XRD, and TGA analysis methods. The CNC was composed of fibrous and spherical or elliptic granules of nano-cellulose with sizes of 50-60 nm. Properties of agar film such as mechanical and water vapor barrier properties were improved significantly (p<0.05) by blending with the CNC. The tensile modulus and tensile strength of agar film increased by 40% and 25%, respectively, in the composite film with 5 wt% of CNC, and the WVP of agar film decreased by 25% after formation of nanocomposite with 3 wt% of CNC. The CNC obtained from the paper-mulberry bast pulp can be used as a reinforcing agent for the preparation of bio-nanocomposites, and they have a high potential for the development of completely biodegradable food packaging materials. PMID:24906782

  17. Novel grafted agar disks for the covalent immobilization of β-D-galactosidase.

    PubMed

    Wahba, Marwa I; Hassan, Mohamed E

    2015-12-01

    Novel grafted agar disks were prepared for the covalent immobilization of β-D-galactosidase (β-gal). The agar disks were activated through reacting with ethylenediamine or different molecular weights of Polyethyleneimine (PEI), followed by glutaraldehyde (GA). The modification of the agar gel and the binding of the enzyme were verified by Fourier Transform Infrared (FTIR) and elemental analysis. Moreover, the agar's activation process was optimized, and the amount of immobilized enzyme increased 3.44 folds, from 38.1 to 131.2 U/g gel, during the course of the optimization process. The immobilization of β-gal onto the activated agar disks caused its optimum temperature to increase from 45°C to 45-55°C. The optimum pH of the enzyme was also shifted towards the acidic side (3.6-4.6) after its immobilization. Additionally, the Michaelis-Menten constant (Km ) increased for the immobilized β-gal as compared to its free counterpart whereas the maximum reaction rate (Vmax ) decreased. The immobilized enzyme was also shown to retain 92.99% of its initial activity after being used for 15 consecutive times. PMID:26043937

  18. Strategies to improve the mechanical strength and water resistance of agar films for food packaging applications.

    PubMed

    Sousa, Ana M M; Gonçalves, Maria P

    2015-11-01

    Agar films possess several properties adequate for food packaging applications. However, their high cost-production and quality variations caused by physiological and environmental factors affecting wild seaweeds make them less attractive for industries. In this work, native (NA) and alkali-modified (AA) agars obtained from sustainably grown seaweeds (integrated multi-trophic aquaculture) were mixed with locust bean gum (LBG) to make 'knife-coated' films with fixed final concentration (1 wt%) and variable agar/LBG ratios. Agar films were easier to process upon LBG addition (viscosity increase and gelling character decrease of the film-forming solutions observed by dynamic oscillatory and steady shear measurements). The mechanical properties and water resistance were optimal for films with 50 and/or 75% LBG contents and best in the case of NA (cheaper to extract). These findings can help reduce the cost-production of agar packaging films. Moreover, the controlled cultivation of seaweeds can provide continuous and reliable feedstock for transformation industries. PMID:26256341

  19. Effects of shape and size of agar gels on heating uniformity during pulsed microwave treatment.

    PubMed

    Soto-Reyes, Nohemí; Temis-Pérez, Ana L; López-Malo, Aurelio; Rojas-Laguna, Roberto; Sosa-Morales, María Elena

    2015-05-01

    Model gel systems with different shape (sphere, cylinder, and slab) and size (180 and 290 g) were prepared with agar (5%) and sucrose (5%). Dielectric constant (ε'), loss factor (ε"), thermophysical properties, and temperature distribution of the model system were measured. Each agar model system was immersed and suspended in water, and then, heated in a microwave oven with intermittent heating until the core temperature reached 50 °C. The ε' and ε" of agar gels decreased when frequency increased. The density and thermal conductivity values of the agar gels were 1033 kg/m(3) and 0.55 W/m °C, respectively. The temperature distribution of sphere, cylinder, and slab was different when similar power doses were applied. The slab reached 50 °C in less time (10 min) and showed a more uniform heating than spheres and cylinders in both sizes. Agar model systems of 180 g heated faster than those of 290 g. The coldest point was the center of the model systems in all studied cases. Shape and size are critical food factors that affect the heating uniformity during microwave heating processes. PMID:25827444

  20. Cost-effective nanoporous Agar-Agar polymer/Nickel powder composite particle for effective bio-products adsorption by expanded bed chromatography.

    PubMed

    Asgari, Setareh; Jahanshahi, Mohsen; Rahimpour, Ahmad

    2014-09-26

    In the present work a novel kind of dense nanoporous composite matrix for expanded bed application has been successfully first prepared with Nickel powder as a densifier and was covered with Agar-Agar layer as a skeleton, through the method of water-in-oil emulsification. Agar-Agar is a porous and inexpensive polymer. In order to fabricate cost-effective adsorbent with favorable qualities Agar-Agar polymer was used. Thereafter, the customized composite particle was modified by pseudo-affinity dye-ligand, Reactive Blue 4 (RB4), aimed at preparing a pseudo-affinity adsorbent (RB4-Agar-Ni) for bioprodut adsorption from aqueous solution. Bovine Serum Albumin (BSA) was selected as a model protein to investigate the adsorption behavior in batchwise and expanded bed chromatography, and the obtained results were evaluated with that of Streamline™ (Amersham-Pharmacia Biotech, Sweden). Spherical appearance and porous structure of composite particles were observed by the optical microscope (OM) and scanning electronic microscope (SEM). The results suggested that the matrices followed the logarithmic normal size distribution with the range of 65-300 μm and average diameter of 126.81-151.47 μm, proper wet density of 1.64-2.78 g/ml, water content of 62.74-34%, porosity of 98-90% and pore size of about 38-130 nm. For better comprehension of the impact of solid phase properties on the performance of the expanded bed, the expansion and hydrodynamic properties of a composite matrix with a series of densities was evaluated and estimated by the retention time distribution method (RTD) in an expanded bed and was compared with that of other matrices. According to obtained results the expansion factors under the same fluid velocity decreased by increasing the matrix density. Moreover, the axial dispersion coefficient (Dax) is the most appropriate parameter for evaluating the stability of expanded bed, on various operating conditions, such as different flow velocity, bed expansion

  1. Simple protocol for secondary school hands-on activity: Electrophoresis of pre-stained nucleic acids on agar-agar borate gels.

    PubMed

    Britos, Leticia; Goyenola, Guillermo; Oroño, Silvia Umpiérrez

    2004-09-01

    An extremely simple, inexpensive, and safe method is presented, which emulates nucleic acids isolation and electrophoretic analysis as performed in a research environment, in the context of a secondary school hands-on activity. The protocol is amenable to an interdisciplinary approach, taking into consideration the electrical and chemical parameters of the electrophoretic system. Furthermore, the laboratory is framed in a more comprehensive pedagogical setting, which addresses the methodological aspects of a pivotal scientific enterprise such as the Human Genome Project. In this setting, the hands-on activity is complemented with animations, paper models, and discussions. Additionally, our results indicate that the use of borate buffer and agar-agar gels suits many of the experiments included in college-level laboratory activities, which currently make use of more expensive agarose gels and TBE or TAE buffers. PMID:21706751

  2. Residual Resistivity of Dilute Alloys

    NASA Astrophysics Data System (ADS)

    Vora, Aditya M.

    The residual resistivity for 156 dilute alloys of 19 hosts of different groups of the periodic table has been studied on the basis of the single parametric model potential formalism. Ashcroft's empty core model (EMC) potential is explored for the first time with five different local field correction functions, viz, Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F), and Sarkar et al. (S) to investigate the effect of the exchange and correlation on the aforesaid properties. The comparison of the presently computed outcomes with the available theoretical and experimental data is highly encouraging. The investigation of residual resistivity is found to be quite sensitive to the selection of local field correction function, showing a significant variation with the change in the function.

  3. Band anticrossing in dilute nitrides

    SciTech Connect

    Shan, W.; Yu, K.M.; Walukiewicz, W.; Wu, J.; Ager III, J.W.; Haller, E.E.

    2003-12-23

    Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the fundamental band-gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-band states and localized N states. The interaction splits the conduction band into two nonparabolic subbands. The downward shift of the lower conduction subband edge is responsible for the N-induced reduction of the fundamental band-gap energy. The changes in the conduction band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.

  4. Desynchronization in diluted neural networks

    SciTech Connect

    Zillmer, Ruediger; Livi, Roberto; Politi, Antonio; Torcini, Alessandro

    2006-09-15

    The dynamical behavior of a weakly diluted fully inhibitory network of pulse-coupled spiking neurons is investigated. Upon increasing the coupling strength, a transition from regular to stochasticlike regime is observed. In the weak-coupling phase, a periodic dynamics is rapidly approached, with all neurons firing with the same rate and mutually phase locked. The strong-coupling phase is characterized by an irregular pattern, even though the maximum Lyapunov exponent is negative. The paradox is solved by drawing an analogy with the phenomenon of 'stable chaos', i.e., by observing that the stochasticlike behavior is 'limited' to an exponentially long (with the system size) transient. Remarkably, the transient dynamics turns out to be stationary.

  5. XAFS in dilute magnetic semiconductors.

    PubMed

    Sun, Zhihu; Yan, Wensheng; Yao, Tao; Liu, Qinghua; Xie, Yi; Wei, Shiqiang

    2013-10-14

    X-Ray absorption fine structure (XAFS) spectroscopy has experienced a rapid development in the last four decades and has proved to be a powerful structure characterization technique in the study of local environments in condensed matter. In this article, we first introduce the XAFS basic principles including theory, data analysis and experiment in some detail. Then we attempt to make a review on the applications of XAFS to the study of atomic and electronic structure in dilute magnetic semiconductor (DMS) systems. The power of XAFS in characterizing this interesting material system, such as determining the occupation sites and distribution of the dopants, detecting the presence of metal clusters or secondary phases, as well as identifying the defect types and dopant valence, will be illuminated by selected examples. This review should be of interest both to newcomers in the DMS field and to an interdisciplinary community of researchers working in synthesis, characterization and utilization of DMS materials. PMID:23884341

  6. Optical streak camera images of wire-array z-pinches on the 1-MA COBRA pulsed power generator

    NASA Astrophysics Data System (ADS)

    McBride, Ryan; Pikuz, Sergei; Blesener, Isaac; Zhao, Yu Tao; Greenly, John; Hammer, David; Kusse, Bruce

    2006-10-01

    Initial optical streak camera imaging experiments of wire array z-pinches on the 1 MA COBRA pulsed power generator are presented. The imaging system makes use of a Hamamatsu C7700 streak unit, which is coupled to a V7669-06 image intensifier with an MCP, and a C4742-98 CCD camera. A long focal length optical system is employed to relay the z-pinch produced light from the experiment chamber to the input slit of the streak camera -- a total transmission distance of approximately 14 m. The optical streak camera images produced, along with data from other supporting diagnostics, are presented for z-pinch implosions of various wire array geometries and materials.

  7. Initial tests of the dual-sweep streak camera system planned for APS particle-beam diagnostics

    SciTech Connect

    Lumpkin, A.; Yang, B.; Gai, W.; Cieslik, W.

    1995-07-01

    Initial tests of a dual-sweep streak system planned for use on the Advanced Photon Source (APS) have been performed using assets of the Argonne Wakefield Accelerator (AWA) facility. The short light pulses from the photoelectric injector drive laser in both the visible ({lambda}=496 nm, {Delta}t{approximately}1.5 ps (FWHM)), and the ultraviolet ({lambda}=248 nm, {Delta}t{approximately}5 ps (FWHM)) were used. Both a UV-visible S20 photocathode streak tube and a UV-to-x-ray Au photocathode streak tube were tested. Calibration data with an etalon were also obtained. A sample of dual-sweep streak data using optical synchrotron radiation on the APS injector synchrotron is also presented.

  8. Streaked radiography of an irradiated foam sample on the National Ignition Facility

    SciTech Connect

    Cooper, A. B. R.; Schneider, M. B.; MacLaren, S. A.; Young, P. E.; Hsing, W. W.; Seugling, R.; Foord, M. E.; Sain, J. D.; May, M. J.; Marrs, R. E.; Maddox, B. R.; Lu, K.; Dodson, K.; Smalyuk, V.; Moore, A. S.; Graham, P.; Foster, J. M.; Back, C. A.; Hund, J. F.

    2013-03-15

    Streaked x-ray radiography images of annular patterns in an evolving tantalum oxide foam under the influence of a driven, subsonic radiation wave were obtained on the National Ignition Facility. This is the first successful radiography measurement of the evolution of well-defined foam features under a driven, subsonic wave in the diffusive regime. A continuous record of the evolution was recorded on an x-ray streak camera, using a slot-apertured point-projection backlighter with an 8 ns nickel source (7.9 keV). Radiography images were obtained for four different annular patterns, which were corrected using a source-dependent flat-field image. The evolution of the foam features was well-modeled using the 3D KULL radiation hydrodynamics code. This experimental and modeling platform can be modified for scaled high-energy-density laboratory astrophysics experiments.

  9. Effects of diabatic heating on the ageostrophic circulation of an upper tropospheric jet streak

    NASA Technical Reports Server (NTRS)

    Keyser, D. A.; Johnson, D. R.

    1982-01-01

    Interaction between the mass circulation within a mesoscale convective complex (MCC) and a direct mass circulation in the entrance region of an upper tropospheric polar jet streak was examined within the isentropic structure to investigate mechanisms responsible for linking these two scales of motion. The results establish that latent heating in the MCC modifies the direct mass circulation in the jet streak entrance region through the diabatically induced components of ageostrophic motion analyzed within isentropic coordinates. Within the strong mesoscale mass circulation of each MCC, strong horizontal mass flux convergence into the MCC at low levels is balanced by strong horizontal mass flux divergence away from the convergence at upper levels. Locations of large diabatic heating rates correspond well to the MCC position for each case; diabatic heating forces the upward vertical branch for the mesoscale mass circulation.

  10. A distinct tospovirus causing necrotic streak on Alstroemeria sp. in Colombia.

    PubMed

    Hassani-Mehraban, Afshin; Botermans, Marleen; Verhoeven, J Th J; Meekes, Ellis; Saaijer, Janneke; Peters, Dick; Goldbach, Rob; Kormelink, Richard

    2010-03-01

    A tospovirus causing necrotic streaks on leaves was isolated from Alstroemeria sp. in Colombia. Infected samples reacted positively with tomato spotted wilt virus (TSWV) antiserum during preliminary serological tests. Further analysis revealed a close serological relationship to tomato chlorotic spot virus (TCSV) and groundnut ringspot virus (GRSV). A major part of the S-RNA segment, encompassing the nucleocapsid (N) protein gene, the 5' untranslated region and a part of the intergenic region 3' of the N gene, was cloned and sequenced. The deduced N protein sequence showed highest amino acid identity (82%) to that of TCSV, indicating that the virus represents a new tospovirus species, for which the name Alstroemeria necrotic streak virus (ANSV) is coined. Phylogenetic analysis based on the N protein sequence revealed that this Alstroemeria-infecting tospovirus clustered with tospoviruses from the American continent. Frankliniella occidentalis was identified as potential vector species for ANSV. PMID:20151164

  11. Time-Resolved Spectra of Dense Plasma Focus Using Spectrometer, Streak Camera, CCD Combination

    SciTech Connect

    F. J. Goldin, B. T. Meehan, E. C. Hagen, P. R. Wilkins

    2010-10-01

    A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny–Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

  12. Time-resolved spectra of dense plasma focus using spectrometer, streak camera, and CCD combination

    SciTech Connect

    Goldin, F. J.; Meehan, B. T.; Hagen, E. C.; Wilkins, P. R.

    2010-10-15

    A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny-Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

  13. Protocol for observing molecular dipole excitations by attosecond self-streaking

    NASA Astrophysics Data System (ADS)

    Wachter, Georg; Nagele, Stefan; Sato, Shunsuke A.; Pazourek, Renate; Wais, Michael; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-12-01

    We propose a protocol to probe the ultrafast evolution and dephasing of coherent electronic excitation in molecules in the time domain by the intrinsic streaking field generated by the molecule itself. Coherent electronic motion in the endohedral fullerene Ne@C 60 is initiated by a moderately intense femtosecond UV-visible pulse leading to coherent oscillations of the molecular dipole moment that persist after the end of the laser pulse. The resulting time-dependent molecular near field is probed through the momentum modulation of photoemission from the central neon atom by a time-delayed attosecond XUV pulse. Our ab initio time-dependent density functional theory and classical trajectory simulations predict that this self-streaking signal accurately traces the molecular dipole oscillations in real time. We discuss the underlying processes and give an analytical model that captures the essence of our ab initio simulations.

  14. Extra-embryonic Wnt3 regulates the establishment of the primitive streak in mice

    PubMed Central

    Yoon, Yeonsoo; Huang, Tingting; Tortelote, Giovane G.; Wakamiya, Maki; Hadjantonakis, Anna-Katerina; Behringer, Richard R.; Rivera-Pérez, Jaime A.

    2015-01-01

    The establishment of the head to tail axis at early stages of development is a fundamental aspect of vertebrate embryogenesis. In mice, experimental embryology, genetics and expression studies have suggested that the visceral endoderm, an extra-embryonic tissue, plays an important role in anteroposterior axial development. Here we show that absence of Wnt3 in the posterior visceral endoderm leads to delayed formation of the primitive streak and that interplay between anterior and posterior visceral endoderm restricts the position of the primitive streak. Embryos lacking Wnt3 in the visceral endoderm, however, appear normal by E9.5. Our results suggest a model for axial development in which multiple signals are required for anteroposterior axial development in mammals. PMID:25907228

  15. Recording the synchrotron radiation by a picosecond streak camera for bunch diagnostics in cyclic accelerators

    NASA Astrophysics Data System (ADS)

    Vereshchagin, A. K.; Vorob'ev, N. S.; Gornostaev, P. B.; Dorokhov, V. L.; Kryukov, S. S.; Lozovoi, V. I.; Meshkov, O. I.; Nikiforov, D. A.; Smirnov, A. V.; Shashkov, E. V.; Schelev, M. Ya

    2016-02-01

    A PS-1/S1 picosecond streak camera with a linear sweep is used to measure temporal characteristics of synchrotron radiation pulses on a damping ring (DR) at the Budker Institute of Nuclear Physics (BINP) of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk). The data obtained allow a conclusion as to the formation processes of electron bunches and their 'quality' in the DR after injection from the linear accelerator. The expediency of employing the streak camera as a part of an optical diagnostic accelerator complex for adjusting the injection from a linear accelerator is shown. Discussed is the issue of designing a new-generation dissector with a time resolution up to a few picoseconds, which would allow implementation of a continuous bunch monitoring in the DR during mutual work with the electron-positron colliders at the BINP.

  16. Route to One Atomic Unit of Time: Development of a Broadband Attosecond Streak Camera

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Zhang, Qi; Chini, Michael; Chang, Zenghu

    A new attosecond streak camera based on a three-meter-long magnetic-bottle time-of-flight electron spectrometer (MBES) is developed. The temporal resolution of the photoelectron detection system is measured to be better than 250 ps, which is sufficient to achieve an energy resolution of 0.5 eV at 150 eV photoelectron energy. In preliminary experiments, a 94-as isolated XUV pulse was generated and characterized. With a new algorithm to retrieve the amplitude and phase of XUV pulses (PROOF—phase retrieval by omega oscillation filtering), the attosecond streak camera will be able to characterize isolated attosecond pulses as short as one atomic unit of time (25 as).

  17. Single-shot visualization of evolving laser wakefields using an all-optical streak camera.

    PubMed

    Li, Zhengyan; Tsai, Hai-En; Zhang, Xi; Pai, Chih-Hao; Chang, Yen-Yu; Zgadzaj, Rafal; Wang, Xiaoming; Khudik, V; Shvets, G; Downer, M C

    2014-08-22

    We visualize ps-time-scale evolution of an electron density bubble--a wake structure created in atmospheric density plasma by an intense ultrashort laser pulse--from the phase "streak" that the bubble imprints onto a probe pulse that crosses its path obliquely. Phase streaks, recovered in one shot using frequency-domain interferometric techniques, reveal the formation, propagation, and coalescence of the bubble within a 3 mm long ionized helium gas target. 3D particle-in-cell simulations validate the observed density-dependent bubble evolution, and correlate it with the generation of a quasimonoenergetic ∼ 100 MeV electron beam. The results provide a basis for understanding optimized electron acceleration at a plasma density n(e) ≈ 2 × 10(19) cm(-3), inefficient acceleration at lower density, and dephasing limits at higher density. PMID:25192102

  18. Temporal resolution limit estimation of x-ray streak cameras using a CsI photocathode

    SciTech Connect

    Li, Xiang; Gu, Li; Zong, Fangke; Zhang, Jingjin; Yang, Qinlao

    2015-08-28

    A Monte Carlo model is developed and implemented to calculate the characteristics of x-ray induced secondary electron (SE) emission from a CsI photocathode used in an x-ray streak camera. Time distributions of emitted SEs are investigated with an incident x-ray energy range from 1 to 30 keV and a CsI thickness range from 100 to 1000 nm. Simulation results indicate that SE time distribution curves have little dependence on the incident x-ray energy and CsI thickness. The calculated time dispersion within the CsI photocathode is about 70 fs, which should be the temporal resolution limit of x-ray streak cameras that use CsI as the photocathode material.

  19. A novel compact high speed x-ray streak camera (invited)

    SciTech Connect

    Hares, J. D.; Dymoke-Bradshaw, A. K. L.

    2008-10-15

    Conventional in-line high speed streak cameras have fundamental issues when their performance is extended below a picosecond. The transit time spread caused by both the spread in the photoelectron (PE) ''birth'' energy and space charge effects causes significant electron pulse broadening along the axis of the streak camera and limits the time resolution. Also it is difficult to generate a sufficiently large sweep speed. This paper describes a new instrument in which the extraction electrostatic field at the photocathode increases with time, converting time to PE energy. A uniform magnetic field is used to measure the PE energy, and thus time, and also focuses in one dimension. Design calculations are presented for the factors limiting the time resolution. With our design, subpicosecond resolution with high dynamic range is expected.

  20. Mach-zehnder based optical marker/comb generator for streak camera calibration

    SciTech Connect

    Miller, Edward Kirk

    2015-03-03

    This disclosure is directed to a method and apparatus for generating marker and comb indicia in an optical environment using a Mach-Zehnder (M-Z) modulator. High speed recording devices are configured to record image or other data defining a high speed event. To calibrate and establish time reference, the markers or combs are indicia which serve as timing pulses (markers) or a constant-frequency train of optical pulses (comb) to be imaged on a streak camera for accurate time based calibration and time reference. The system includes a camera, an optic signal generator which provides an optic signal to an M-Z modulator and biasing and modulation signal generators configured to provide input to the M-Z modulator. An optical reference signal is provided to the M-Z modulator. The M-Z modulator modulates the reference signal to a higher frequency optical signal which is output through a fiber coupled link to the streak camera.

  1. Comparison of a new, bismuth-iron-sulfite-cycloserine agar for isolation of Clostridium perfringens with the tryptose-sulfite-cycloserine and blood agars.

    PubMed

    Gubash, S M; Ingham, L

    1997-02-01

    A new differential and selective, bismuth-iron-sulfite-cycloserine (BISC) medium, for isolation and enumeration of Clostridium perfringens from food and feces, was developed. The medium was compared with the widely-used tryptose-sulfite-cycloserine (TSC) medium and blood agar (BA) in recovering actively growing cells, cold- (refrigerated and frozen) stressed, and heat-stressed C. perfringens cells, and heat-activated spores from human feces. Both selective media were satisfactory in recovering actively growing cells and heat-activated spores of C. perfringens. Both were inferior to non-inhibitory blood agar in recovering heat or cold-stressed cells. The advantages of the new BISC medium over the TSC medium were: elimination of the need to prepare pour- or overlay-agar plates, which simplified inoculation of specimens on the medium and simplified the subcultures of colonies for confirmatory identification. All colonies of C. perfringens developed on BISC were black or dark gray. This was contrary to TSC medium, which gave, on average, 39.6% of white colonies when inoculated with the pure cultures of C. perfringens. PMID:9084113

  2. High-Speed Observer: Automated Streak Detection for the Aerospike Engine

    NASA Technical Reports Server (NTRS)

    Rieckhoff, T. J.; Covan, M. A.; OFarrell, J. M.

    2001-01-01

    A high-frame-rate digital video camera, installed on test stands at Stennis Space Center (SSC), has been used to capture images of the aerospike engine plume during test. These plume images are processed in real time to detect and differentiate anomalous plume events. Results indicate that the High-Speed Observer (HSO) system can detect anomalous plume streaking events that are indicative of aerospike engine malfunction.

  3. Complete genome sequence of an emerging genotype of tobacco streak virus in the United States.

    PubMed

    Padmanabhan, Chellappan; Gao, Shan; Li, Rugang; Zhang, Shouan; Fei, Zhangjun; Ling, Kai-Shu

    2014-01-01

    We report here the complete genome sequence of an emerging genotype of tobacco streak virus (TSV) infecting zucchini squash in Florida (TSV_FL13-07), obtained using deep sequencing of short RNAs (sRNAs) and validation by Sanger sequencing. TSV_FL13-07 shares only <90% sequence identity in all three genomic RNAs to several known U.S. isolates. PMID:25377714

  4. Molecular organization of the cholesteryl ester droplets in the fatty streaks of human aorta.

    PubMed Central

    Engelman, D M; Hillman, G M

    1976-01-01

    X-ray diffraction patterns from human arterial specimens containing atherosclerotic fatty streak lesions exhibited a single sharp reflection, corresponding to a structural spacing of about 35 A. Specimens without lesions did not. When specimens with fatty streaks were heated, an order-to-disorder phase transition was revealed by the disappearance of the sharp reflection. The transition was thermally reversible and its temperature varied from aorta to aorta over a range from 28 degrees to 42 degrees C. Since cholesteryl ester droplets are a major component of fatty streaks, comparison studies were made of the diffraction behavior from pure cholesteryl esters. We found that the diffraction patterns of the fatty streak material could be accounted for by the organization of the cholesteryl esters into a liquid-crystalline smectic phase that melts from the smectic to a less ordered phase upon heating. When combined with the conclusions of others from polarized light microscopy, our study shows that a droplet in the smectic phase has well-defined concentric layers of lipid molecules. In each layer, the long axes of the molecules have a net radial orientation with respect to the droplet, but the side-to-side organization is disordered. We suggest that the accessibility of portions of the lipids for specific binding to enzymes or transport proteins may be restricted when they are in the smectic state, and that exchange of lipids with surrounding membranes or other potential binding sites may likewise be inhibited. The restriction in the smectic phase should be greater than in the less ordered phases that exist at higher temperatures. Images PMID:965500

  5. 2-ps Hard X-Ray Streak Camera Measurements at Sector 7 Beamline of the Advanced Photon Source

    SciTech Connect

    Chollet, M.; Ahr, B.; Walko, D.A.; Rose-Petruck, C.; Adams, B.

    2011-08-02

    A hard X-ray streak camera capable of 2-ps time resolution is in operation at the Sector 7 beamline of the Advanced Photon Source. It is used for laser-pump, X-ray probe experiments using the Ti:Sapphire femtosecond laser system installed on the beamline. This streak camera, combined with standardized and prealigned experimental setups, can perform time-resolved liquid-phase absorption spectroscopy, reflectivity, and diffraction experiments.

  6. RNAi-mediated resistance to Cassava brown streak Uganda virus in transgenic cassava.

    PubMed

    Yadav, Jitender S; Ogwok, Emmanuel; Wagaba, Henry; Patil, Basavaprabhu L; Bagewadi, Basavaraj; Alicai, Titus; Gaitan-Solis, Eliana; Taylor, Nigel J; Fauquet, Claude M

    2011-09-01

    Cassava brown streak disease (CBSD), caused by Cassava brown streak Uganda virus (CBSUV) and Cassava brown streak virus (CBSV), is of new epidemic importance to cassava (Manihot esculenta Crantz) production in East Africa, and an emerging threat to the crop in Central and West Africa. This study demonstrates that at least one of these two ipomoviruses, CBSUV, can be efficiently controlled using RNA interference (RNAi) technology in cassava. An RNAi construct targeting the near full-length coat protein (FL-CP) of CBSUV was expressed constitutively as a hairpin construct in cassava. Transgenic cassava lines expressing small interfering RNAs (siRNAs) against this sequence showed 100% resistance to CBSUV across replicated graft inoculation experiments. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed the presence of CBSUV in leaves and some tuberous roots from challenged controls, but not in the same tissues from transgenic plants. This is the first demonstration of RNAi-mediated resistance to the ipomovirus CBSUV in cassava. PMID:21726367

  7. Development of intelligent control system for X-ray streak camera in diagnostic instrument manipulator

    NASA Astrophysics Data System (ADS)

    Pei, Chengquan; Wu, Shengli; Tian, Jinshou; Liu, Zhen; Fang, Yuman; Gao, Guilong; Liang, Lingliang; Wen, Wenlong

    2015-11-01

    An intelligent control system for an X ray streak camera in a diagnostic instrument manipulator (DIM) is proposed and implemented, which can control time delay, electric focusing, image gain adjustment, switch of sweep voltage, acquiring environment parameters etc. The system consists of 16 A/D converters and 16 D/A converters, a 32-channel general purpose input/output (GPIO) and two sensors. An isolated DC/DC converter with multi-outputs and a single mode fiber were adopted to reduce the interference generated by the common ground among the A/D, D/A and I/O. The software was designed using graphical programming language and can remotely access the corresponding instrument from a website. The entire intelligent control system can acquire the desirable data at a speed of 30 Mb/s and store it for later analysis. The intelligent system was implemented on a streak camera in a DIM and it shows a temporal resolution of 11.25 ps, spatial distortion of less than 10% and dynamic range of 279:1. The intelligent control system has been successfully used in a streak camera to verify the synchronization of multi-channel laser on the Inertial Confinement Fusion Facility.

  8. High-Throughput Single-Cell Cultivation on Microfluidic Streak Plates.

    PubMed

    Jiang, Cheng-Ying; Dong, Libing; Zhao, Jian-Kang; Hu, Xiaofang; Shen, Chaohua; Qiao, Yuxin; Zhang, Xinyue; Wang, Yapei; Ismagilov, Rustem F; Liu, Shuang-Jiang; Du, Wenbin

    2016-04-01

    This paper describes the microfluidic streak plate (MSP), a facile method for high-throughput microbial cell separation and cultivation in nanoliter sessile droplets. The MSP method builds upon the conventional streak plate technique by using microfluidic devices to generate nanoliter droplets that can be streaked manually or robotically onto petri dishes prefilled with carrier oil for cultivation of single cells. In addition, chemical gradients could be encoded in the droplet array for comprehensive dose-response analysis. The MSP method was validated by using single-cell isolation of Escherichia coli and antimicrobial susceptibility testing of Pseudomonas aeruginosa PAO1. The robustness of the MSP work flow was demonstrated by cultivating a soil community that degrades polycyclic aromatic hydrocarbons. Cultivation in droplets enabled detection of the richest species diversity with better coverage of rare species. Moreover, isolation and cultivation of bacterial strains by MSP led to the discovery of several species with high degradation efficiency, including four Mycobacterium isolates and a previously unknown fluoranthene-degrading Blastococcus species. PMID:26850294

  9. Attosecond streaking of molecules in the low-energy region studied by a wavefunction splitting scheme

    NASA Astrophysics Data System (ADS)

    Hou, Xue-Feng; Peng, Liang-You; Ning, Qi-Cheng; Gong, Qihuang

    2012-04-01

    We present a theoretical study of the low-energy photoelectron spectra of hydrogen molecular ion generated by a single attosecond pulse in the presence of an infrared (IR) laser field. In order to investigate this type of attosecond streaking of molecules, we developed a very efficient grid-based numerical method to solve the two-centre time-dependent Schrödinger equation (TDSE) in the prolate spheroidal coordinates. Specifically, the radial coordinate is discretized with the finite-element discrete variable representation (FE-DVR) for easy parallel computation and the angular coordinate with the usual DVR. A wavefunction splitting scheme is utilized to reduce the demanding requirement of the computational resource to solve the corresponding TDSE when an IR field is present. After verification of the accuracy and efficiency of our method, we then apply it to investigate the attosecond streaking spectra of H+2 in the low-energy region. In contrast to the usual attosecond streaking in the high-energy region, part of the low-energy electrons may be driven back to rescatter with the residual two-centre core. Very interesting interference structures are present in the low-energy region. When the internuclear distance is small, they are very similar to what we have recently observed in the atomic case.

  10. Optical fiducial timing system for X-ray streak cameras with aluminum coated optical fiber ends

    DOEpatents

    Nilson, David G.; Campbell, E. Michael; MacGowan, Brian J.; Medecki, Hector

    1988-01-01

    An optical fiducial timing system is provided for use with interdependent groups of X-ray streak cameras (18). The aluminum coated (80) ends of optical fibers (78) are positioned with the photocathodes (20, 60, 70) of the X-ray streak cameras (18). The other ends of the optical fibers (78) are placed together in a bundled array (90). A fiducial optical signal (96), that is comprised of 2.omega. or 1.omega. laser light, after introduction to the bundled array (90), travels to the aluminum coated (82) optical fiber ends and ejects quantities of electrons (84) that are recorded on the data recording media (52) of the X-ray streak cameras (18). Since both 2.omega. and 1.omega. laser light can travel long distances in optical fiber with only a slight attenuation, the initial arial power density of the fiducial optical signal (96) is well below the damage threshold of the fused silica or other material that comprises the optical fibers (78, 90). Thus the fiducial timing system can be repeatably used over long durations of time.

  11. Altitude Starting Characteristics of an Afterburner with Autoignition and Hot-streak Ignition

    NASA Technical Reports Server (NTRS)

    Renas, P E; Jansen, E T; Harvey, R W , Sr

    1953-01-01

    An investigation was conducted in an altitude test chamber at the NACA Lewis Laboratory to determine the altitude starting characteristics of an afterburner with autoignition and with hot-streak ignition. Transient afterburner ignition data were obtained over a range of altitudes from 30,000 to 50,000 feet at a flight Mach number of 0.60. Afterburner ignition with a torch igniter located axially at approximately the midpoint of the combustion chamber was possible over the entire range, but ignition ignition with a torch igniter located in the transition section 1 5/8 inches upstream of the turbine stators proved unsatisfactory at an altitude of 50,000 feet due to the inability to obtain flame through the turbine. Increasing the afterburner-inlet total pressure at a constant afterburner fuel-air ratio decreased the afterburner ignition time. Hot-streak ignition was possible within 2 seconds after the time required to obtain the preset, normal afterburner fuel pressure, whereas autoignition required 4 to 7 seconds for the range of altitudes investigated. Following the ignition there was a period of oscillatory operation existing in the engine-afterburner before steady-state operation was attained. The time required for steady-state stable operation decreased as afterburner inlet total pressure increased. The duration of oscillations also decreased with hot-streak ignition because the fuel-air mixture was ignited before a large volume of combustible mixture was accumulated in the afterburner.

  12. Artificial microRNA-derived resistance to Cassava brown streak disease

    PubMed Central

    Wagaba, Henry; Patil, Basavaprabhu L.; Mukasa, Settumba; Alicai, Titus; Fauquet, Claude M.; Taylor, Nigel J.

    2016-01-01

    Artificial miRNAs (amiRNA) were generated targeting conserved sequences within the genomes of the two causal agents of Cassava brown streak disease (CBSD): Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). Transient expression studies on ten amiRNAs targeting 21 nt conserved sequences of P1(CBSV and UCBSV), P3(CBSV and UCBSV), CI(UCBSV), NIb(CBSV and UCBSV), CP(UCBSV) and the un-translated region (3′-UTR) were tested in Nicotiana benthamiana. Four out of the ten amiRNAs expressed the corresponding amiRNA at high levels. Transgenic N. benthamiana plants were developed for the four amiRNAs targeting the P1 and NIb genes of CBSV and the P1 and CP genes of UCBSV and shown to accumulate miRNA products. Transgenic plants challenged with CBSV and UCBSV isolates showed resistance levels that ranged between ∼20–60% against CBSV and UCBSV and correlated with expression levels of the transgenically derived miRNAs. MicroRNAs targeting P1 and NIb of CBSV showed protection against CBSV and UCBSV, while amiRNAs targeting the P1 and CP of UCBSV showed protection against UCBSV but were less efficient against CBSV. These results indicate a potential application of amiRNAs for engineering resistance to CBSD-causing viruses in cassava. PMID:26912232

  13. Unsteady numerical simulation of hot streak/blades interaction and film cooling

    NASA Astrophysics Data System (ADS)

    Yi, Weilin; Ji, Lucheng; Xiao, Yunhan

    2010-10-01

    Deeply research on management and application of hot streak is an important way to breakthrough technique obstacle of aero engine hot components. Numerical method is a useful instrument to investigate the correlative problems. Firstly the paper developed independently three dimensional unsteady parallel computational code-MpiTurbo based on Fortran 90 and MPI at Linux operating system. Then unsteady numerical simulation was carried out to investigate impacts of the factors, which included circumferential locations of hot streak and clocking positions of blade rows, on the thermal environment of a 1+1 counter-rotating turbine. The results clearly indicated that clocking positions of hot streak/blade row and blade row/blade row had great influence on the time-averaged temperature distribution of the third blade row. Therefore, it can be effective for improving thermal environment of turbine to optimize blade parameters and clocking positions. Lastly film cooling layout was designed by the repetitious steady simulation based on source term method. And the flow structure detail was given by the unsteady simulation.

  14. A possible scenario for the evolution of Banana streak virus in banana.

    PubMed

    Iskra-Caruana, Marie-Line; Chabannes, Matthieu; Duroy, Pierre-Olivier; Muller, Emmanuelle

    2014-06-24

    Outbreaks of Banana streak virus (BSV) have been recorded worldwide where Musa spp. is grown during the last 20 years with no convincing evidence of epidemics. Epidemics were previously reported in Uganda where BSV is currently endemic. BSV is a plant pararetrovirus of the family Caulimoviridae, genus Badnavirus it causes chlorosis leaf streak disease. The information currently available on banana streak disease makes it possible to identify a complex of distinct BSV species each causing the same disease. BSV exists in two states: one as an episomal form, infecting plant cells; the other as viral DNA integrated within the B genome of banana (endogenous BSV-eBSV) forming a viral genome for de novo viral particles. Both forms can be infectious in banana plants. The BSV phylogeny is polyphyletic with BSV distributed in two clades. Clade 1 clusters BSV species that occur worldwide and may have an eBSV counterpart, whereas Clade 3 only comprises BSV species from Uganda. Clearly, two distinct origins explain such BSV diversity. However, the epidemiology/outbreaks of BSV remains unclear and the role of eBSV needs to be clarified. In this review, the biodiversity of BSV is explained and discussed in the light of field and molecular epidemiology data. A scheme is proposed for the co-evolution of BSV and banana based on old or recent infection hypotheses related to African domestication sites and banana dissemination to explain the disease context. PMID:24457073

  15. Artificial microRNA-derived resistance to Cassava brown streak disease.

    PubMed

    Wagaba, Henry; Patil, Basavaprabhu L; Mukasa, Settumba; Alicai, Titus; Fauquet, Claude M; Taylor, Nigel J

    2016-05-01

    Artificial miRNAs (amiRNA) were generated targeting conserved sequences within the genomes of the two causal agents of Cassava brown streak disease (CBSD): Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). Transient expression studies on ten amiRNAs targeting 21nt conserved sequences of P1(CBSV and UCBSV), P3(CBSV and UCBSV), CI(UCBSV), NIb(CBSV and UCBSV), CP(UCBSV) and the un-translated region (3'-UTR) were tested in Nicotiana benthamiana. Four out of the ten amiRNAs expressed the corresponding amiRNA at high levels. Transgenic N. benthamiana plants were developed for the four amiRNAs targeting the P1 and NIb genes of CBSV and the P1 and CP genes of UCBSV and shown to accumulate miRNA products. Transgenic plants challenged with CBSV and UCBSV isolates showed resistance levels that ranged between ∼20-60% against CBSV and UCBSV and correlated with expression levels of the transgenically derived miRNAs. MicroRNAs targeting P1 and NIb of CBSV showed protection against CBSV and UCBSV, while amiRNAs targeting the P1 and CP of UCBSV showed protection against UCBSV but were less efficient against CBSV. These results indicate a potential application of amiRNAs for engineering resistance to CBSD-causing viruses in cassava. PMID:26912232

  16. Laser Activated Streak Camera for Measurement of Electron Pulses with Femtosecond Resolution

    NASA Astrophysics Data System (ADS)

    Zandi, Omid; Desimone, Alice; Wilkin, Kyle; Yang, Jie; Centurion, Martin

    2015-05-01

    The duration of femtosecond electron pulses used in time-resolved diffraction and microscopy experiments is challenging to measure in-situ. To overcome this problem, we have fabricated a streak camera that uses the time-varying electric field of a discharging parallel plate capacitor. The capacitor is discharged using a laser-activated GaAs photoswitch, resulting in a damped oscillation of the electric field. The delay time between the laser pulse and electron pulse is set so that the front and back halves of the bunch encounter opposite electric fields of the capacitor and are deflected in opposite directions. Thus, the electron bunch appears streaked on the detector with a length proportional to its duration. The temporal resolution of the streak camera is proportional to the maximum value of the electric field and the frequency of the discharge oscillation. The capacitor is charged by high voltage short pulses to achieve a high electric field and prevent breakdown. We have achieved an oscillation frequency in the GHz range by reducing the circuit size and hence its inductance. The camera was used to measure 100 keV electron pulses with up to a million electrons that are compressed transversely by magnetic lenses and longitudinally by an RF cavity. This work was supported mainly by the Air Force Office of Scientific Research, Ultrashort Pulse Laser Matter Interaction program, under grant # FA9550-12-1-0149.

  17. Effect of Diethylaminoethyl Dextran on the Growth of Mycoplasma in Agar

    PubMed Central

    Tauraso, Nicola M.

    1967-01-01

    The growth of certain strains of Mycoplasma is inhibited by substances present in commercial agar preparations. The addition of diethylaminoethyl (DEAE) dextran (10 mg per 100 ml) to agar media appears to enhance the growth of some strains. Of eight strains initially tested, the presence of DEAE dextran grossly enhanced the growth of three strains. One strain appeared not to be affected, and a clearly enhancing effect was not evident with four strains. Quantitative studies revealed that growth enhancement varied from 10 colony-forming units (CFU) for M. hominis type II (strain Campo) to 103.3 CFU for M. pulmonis (strain 880). The growth-enhancing effect is probably due to the ability of DEAE dextran to bind the sulfated polysaccharide moieties in agar and not to the DEAE dextran, per se. Images PMID:6025444

  18. An agar diffusion study comparing the antimicrobial activity of Nanoseal with some other endodontic sealers.

    PubMed

    Aal-Saraj, Ali Burak; Ariffin, Zaihan; Masudi, Sam'an Malik

    2012-08-01

    The aim of this study was to evaluate the antimicrobial activity of a new experimental nano-hydroxyapatite epoxy resin-based sealer (Nanoseal) with several other commercially available sealers; AH26, Tubliseal, Sealapex and Roekoseal against Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sobrinus and Escherichia coli for up to 7 days. Agar diffusion was used in this study. Fifty Muller-Hinton agar plates were prepared and divided into five experimental groups (n = 10), for each micro-organism. Another 10 agar plates were used as positive and negative controls. Endodontic sealers were tested against each micro-organism. Inhibition zones produced were recorded. The results of this study showed that all test materials exhibited inhibition zones towards the tested micro-organisms for 7 days except for Roekoseal, which showed no inhibition zones. Nanoseal and AH26 exhibited similar zones of inhibition. Significant difference was found between Nanoseal and the other tested sealers (P < 0.001). PMID:22827817

  19. Blood agar to detect virulence factors in tap water heterotrophic bacteria.

    PubMed Central

    Payment, P; Coffin, E; Paquette, G

    1994-01-01

    Cytolytic colonies were found in 57% of tap water samples, and up to 6% of samples were found to contain bacteria having three or more virulence factors. The factors evaluated were cytotoxicity, hemolysis, cell adherence, and cell invasiveness. Overall, 17% of the samples contained cytolytic colonies that were adherent and hemolytic. Among the media tested, tryptic soy agar with sheep blood (incubated at 35 degrees C for 48 h) was the best medium for the detection of cytolytic colonies. Of the colonies growing on this medium, 13% were cytolytic, whereas on medium R2A, less than 3% were cytolytic. Furthermore, when tryptic soy agar with blood was used, 24% of the samples contained colonies with at least three virulence factors whereas only 5% were positive with R2A. Routine monitoring by using tryptic soy agar with sheep blood is suggested as an appropriate procedure for the detection of bacteria with pathogenic potential in drinking water. PMID:8017913

  20. [DNA and chemical analyses of commercial fly agaric-related products].

    PubMed

    Maruyama, Takuro; Kawahara, Nobuo; Fukiharu, Toshimitsu; Yokoyama, Kazumasa; Makino, Yukiko; Goda, Yukihiro

    2005-04-01

    Since June 6, 2002, psilocin and psilocybin-containing fungi (commonly called "magic mushrooms") have been regulated by the Narcotics and Psychotropics Control Law in Japan. However, various fly agaric-related products are now entering the Japanese market via the internet. In this study, fly agaric-related products available in this way were investigated for raw materials by DNA analysis and for additives by chemical analysis. Nucleotide sequence analysis of the mitochondrial 12S rDNA region suggested that these fly agaric-related products originate from A. muscaria or A. muscaria var. persicina. Furthermore, they were classified into three strains based on the ITS2-LSU nucleotide sequence. Harmine derivatives and/or tryptamine derivatives were detected in some of these products by LC/MS analysis. In accordance with this, the matK gene of Peganum harmala was found in all of the harmine derivative-containing samples. PMID:16018591

  1. Homogeneous Matrix Deposition on Dried Agar for MALDI Imaging Mass Spectrometry of Microbial Cultures

    NASA Astrophysics Data System (ADS)

    Hoffmann, Thomas; Dorrestein, Pieter C.

    2015-11-01

    Matrix deposition on agar-based microbial colonies for MALDI imaging mass spectrometry is often complicated by the complex media on which microbes are grown. This Application Note demonstrates how consecutive short spray pulses of a matrix solution can form an evenly closed matrix layer on dried agar. Compared with sieving dry matrix onto wet agar, this method supports analyte cocrystallization, which results in significantly more signals, higher signal-to-noise ratios, and improved ionization efficiency. The even matrix layer improves spot-to-spot precision of measured m/z values when using TOF mass spectrometers. With this technique, we established reproducible imaging mass spectrometry of myxobacterial cultures on nutrient-rich cultivation media, which was not possible with the sieving technique.

  2. Growth kinetics of Salmonella enterica in Hajna tetrathionate broth, Rappaport broth and modified semisolid Rappaport agar

    PubMed Central

    FUJIHARA, Masatoshi; TABUCHI, Hiroyuki; UEGAKI, Kaho

    2015-01-01

    To determine the appropriate method for isolating Salmonella enterica, we compared the growth of S. enterica serovars using three selective enrichment media. S. enterica was more successfully isolated from artificially contaminated fecal samples after enrichment in Hajna tetrathionate broth or modified semisolid Rappaport agar than in Rappaport broth. Since most bacteria (other than motile S. enterica) do not migrate on modified semisolid Rappaport agar, the growth characteristics of S. enterica can be interpreted easily and quickly. Two S. enterica isolates did not migrate on modified semisolid Rappaport agar, but did grow in Hajna tetrathionate broth, which suggests that the combined use of these selective enrichment media is appropriate for isolating S. enterica. PMID:26498402

  3. Low Albedo Surfaces and Eolian Sediment: Mars Orbiter Camera Views of Western Arabia Terra Craters and Wind Streaks

    NASA Technical Reports Server (NTRS)

    Edgett, Kenneth S.

    2001-01-01

    High spatial resolution (1.5 to 12 m/pixel) Mars Global Surveyor Mars Orbiter Camera images obtained September 1997 through June 2001 indicate that the large, dark wind streaks of western Arabia Terra each originate at a barchan dune field on a crater floor. The streaks consist of a relatively thin coating of sediment deflated from the dune fields and their vicinity. This sediment drapes a previous mantle that more thickly covers nearly all of western Arabia Terra. No dunes or eolian bedforms are found within the dark wind streaks, nor do any of the intracrater dunes climb up crater walls to provide sand to the wind streaks. The relations between dunes, wind streak, and subjacent terrain imply that dark-toned grains finer than those which comprise the dunes are lifted into suspension and carried out of the craters to be deposited on the adjacent terrain. Such grains are most likely in the silt size range (3.9-62.5 micrometers). The streaks change in terms of extent, relative albedo, and surface pattern over periods measured in years, but very little evidence for recent eolian activity (dust plumes, storms, dune movement) has been observed.

  4. Serogroup identification of Neisseria meningitidis: comparison of an antiserum agar method with bacterial slide agglutination.

    PubMed Central

    Craven, D E; Frasch, C E; Robbins, J B; Feldman, H A

    1978-01-01

    A serum agar method for serogrouping Neisseria meningitidis is described and compared with conventional bacterial slide agglutination. There was 93% agreement for 300 strains examined individually by each method. Among strains from serogroups A, B, C, Y, and W135, there was 100% correlation, whereas strains from serogroup 29E (Z') had only 67% correlation. The serum agar method was rapid, as well as easy to perform and interpret. The potential benefits of this method for epidemiological studies and reference laboratories processing large numbers of meningococcal isolates are emphasized. Images PMID:96123

  5. Casein Agar: a Useful Medium for Differentiating Candida dubliniensis from Candida albicans

    PubMed Central

    Mosca, Christian O.; Moragues, María D.; Llovo, José; Al Mosaid, Asmaa; Coleman, David C.; Pontón, José

    2003-01-01

    Production of chlamydospores on casein agar at 24°C for 48 h provides a simple means for differentiating Candida dubliniensis from Candida albicans based on chlamydospore production. Of 109 C. dubliniensis isolates tested on this medium, 106 (97.2%) produced abundant chlamydospores and three produced few chlamydospores. In contrast, of the 120 C. albicans isolates tested, 111 (92.5%) failed to produce any chlamydospores, whereas the remaining nine isolates produced few chlamydospores. These findings indicate that abundant chlamydospore production on casein agar is a useful test for discriminating between C. dubliniensis and C. albicans. PMID:12624062

  6. Electrocoalescence based serial dilution of microfluidic droplets

    PubMed Central

    Bhattacharjee, Biddut; Vanapalli, Siva A.

    2014-01-01

    Dilution of microfluidic droplets where the concentration of a reagent is incrementally varied is a key operation in drop-based biological analysis. Here, we present an electrocoalescence based dilution scheme for droplets based on merging between moving and parked drops. We study the effects of fluidic and electrical parameters on the dilution process. Highly consistent coalescence and fine resolution in dilution factor are achieved with an AC signal as low as 10 V even though the electrodes are separated from the fluidic channel by insulator. We find that the amount of material exchange between the droplets per coalescence event is high for low capillary number. We also observe different types of coalescence depending on the flow and electrical parameters and discuss their influence on the rate of dilution. Overall, we find the key parameter governing the rate of dilution is the duration of coalescence between the moving and parked drop. The proposed design is simple incorporating the channel electrodes in the same layer as that of the fluidic channels. Our approach allows on-demand and controlled dilution of droplets and is simple enough to be useful for assays that require serial dilutions. The approach can also be useful for applications where there is a need to replace or wash fluid from stored drops. PMID:25379096

  7. The ring phenomenon of diluted blood droplets.

    PubMed

    Ramsthaler, Frank; Schlote, J; Wagner, C; Fiscina, J; Kettner, M

    2016-05-01

    Bloodstain pattern analysis is occasionally required in practical forensic casework. Misinterpretations may occur in cases in which diluted bloodstains are formed either within the course of the crime or during cleaning attempts after the original crime. The resulting pale or diluted aspect of the bloodstains may also be produced by passive serum separation. To differentiate between diluted and non-diluted stains and the artifacts of pure serum separation, dripping experiments were performed using droplets of multiple sizes and dilutions dripped onto common indoor and fabric surfaces. In addition, pools of blood of different volumes were applied to solid surfaces with different inclinations to determine the conditions and properties of serum separation. This study yielded morphological characteristics that enable differentiation between stains of diluted and non-diluted blood: a prominent ring phenomenon indicates dilution with water. To elucidate the underlying physical mechanism of particle distribution within a blood stain, photomicrographs were taken during the drying process. The so-called contact line pinning effect was identified as the formation mechanism of this ring phenomenon. Serum separation was highly dependent on the applied blood volume, the ambient temperature, the time elapsed since the initial deposition, and the degree of floor inclination. PMID:26718842

  8. Thin agar film for enhanced fungal growth and microscopic viewing in a new sealable fungal culture case.

    PubMed

    Hill, D R

    1996-09-01

    This project was undertaken to find ways to enhance fungus colony maturation, to make viewing of fungal cultures easier, and to reduce disruption of the fungal structures to be observed for identification. Accordingly, a technique using a thin (0.2-mm) agar film that avoids problems inherent in traditional methods of fungal culture and identification was developed. In addition, to accommodate the 0.2-mm layer of agar film and a contiguous thicker 4-mm section of agar, a sealable fungal culture case that fits within microscope stage calipers and under the objective lenses was invented. The growth and identification of 28 organisms were evaluated in the sealable fungal culture cases and on double-pour agar plates by using potato dextrose agar in both. Compared with results obtained with the double-pour agar plates (rated as "good"), fungal growth and identification with the sealable fungal culture case were superior (rated as "excellent") (P < 0.05, chi-square test). The thin agar film limits excessive mycelial growth, while it often promotes complete sporulation or other forms of maturation of the fungal colony. More importantly, the thin agar film allows direct microscopic viewing of the developing fungal colonies. The portion of the sealable fungal culture case with the 4-mm layer of agar can be used for evaluation of colony pigment and texture. In conclusion, this new sealable fungal culture case allows direct viewing and earlier fungal species identification with greater intrinsic safety. PMID:8862573

  9. DAVINCI a Dilute Aperture Coronagraph

    NASA Astrophysics Data System (ADS)

    Shao, Michael

    2009-01-01

    The motivation for DAVINCI was originally to make use of the technology developed for space interferometers like SIM to build a coronagraph from four 1.1m telescopes that was dramatically lower in cost than a 4 5m filled aperture offaxis coronagraph. Our initial studies through team X have shown this cost savings to be real. But a more careful analysis showed that DAVINCI would have an inner working angle of 35mas a factor of 2 smaller than a 2 lambda/D 4 meter coronagraph or 70m external occulter, resulting in a 10X increase in the number of potential Earth-Clone targets. DAVINCI uses a nulling interferometer as a coronagraph, a nulling interferometer is one the few coronagraph architectures that are compatible with segmented and dilute aperture telescopes. Combined with a post coronagraph wavefront sensor several ultra-demanding tolerances of conventional coronagraphs can be relaxed by factors of 100. The post coronagraph wavefront sensor is also much less affected by local and exozodi background than wavefront sensors that use the science camera as the wavefront sensor. The post coronagraph interferometer is also used on ground based extreme AO coronagraphs, GPI, and P1640.

  10. Color-dilution alopecia in dogs.

    PubMed

    Kim, Jae Hoon; Kang, Kyung Il; Sohn, Hyun Joo; Woo, Gye Hyeong; Jean, Young Hwa; Hwang, Eui Kyung

    2005-09-01

    Color-dilution alopecia is a relatively uncommon hereditary skin disease seen in "Blue" and other color-diluted dogs. This syndrome is associated with a color-dilution gene. The initial clinical signs are the gradual onset of a dry, dull and poor hair coat quality. Hair shafts and hair regrowth are poor, and follicular papules may develop and progress to frank comedones. Hair loss and comedo formation are usually most severe on the trunk, especially color-diluted area on the skin. Six cases of color-dilution alopecia are reported in 3 months to 10 years old dogs. The breeds of dogs are blue Doberman Pinscher, Miniature Pinscher, Dachshund, and Schnauzer. Grossly, extensive partial hair loss was seen on the skin. Histopathologically, the epidermis is relatively normal but may be hyperplastic. Hair follicles are characterized by atrophy and distortion. Heavily clumped melanin is present in the epidermis, dermis and hair follicles. PMID:16131833

  11. Applying Agar's Concept of "Languaculture" to Explain Asian Students' Experiences in the Australian Tertiary Context

    ERIC Educational Resources Information Center

    Norris, Lindy; Tsedendamba, Nara

    2015-01-01

    This paper reports part of a broader qualitative case study of Asian students "translation" (Agar, 2006) to study in an Australian university. The paper is concerned with the experiences of eight participants and their involvement in a training programme in the use of language learning strategies (LLS) to support their engagement with…

  12. Development of hyperspectral imaging technique for salmonella enteritidis and typhimurium on agar plates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella is a common cause of foodborne disease resulting from the consumption of contaminated food products. Although a direct plating method is widely used for presumptive positive screening of pathogenic Salmonella colonies on agar plates, it is labor-intensive, time-consuming and also prone to...

  13. THE MICROGARDENING COOKBOOK, DIRECTIONS FOR PREPARING DISHES AND TUBES OF STERILE NUTRIENT AGAR.

    ERIC Educational Resources Information Center

    CHANDLER, MARION N.

    THIS BOOKLET WAS PREPARED FOR TEACHER USE IN ASSOCIATION WITH THE ELEMENTARY SCIENCE STUDY UNIT "MICROGARDENING." IT CONTAINS DIRECTIONS FOR PREPARING CULTURE DISHES AND TUBES OF NUTRIENT STERILE AGAR FOR FUNGAL AND/OR BACTERIAL GROWTH. IT INCLUDES (1) LISTS OF NEEDED SUPPLIES AND EQUIPMENT, (2) DIRECTIONS FOR THE PREPARATION AND STERILIZATION OF…

  14. Comparison of the antibacterial activity of chelating agents using the agar diffusion method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agar diffusion assay was used to examine antibacterial activity of 2 metal chelators. Concentrations of 0 to 40 mM of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine-N,N’-disuccinic acid (EDDS) were prepared in 1.0 M potassium hydroxide (KOH). The pH of the solutions was adjusted to 1...

  15. Mercury in fruiting bodies of Fly Agaric Amanita muscaria (L.: Fr.) Pers. collected from Poland

    NASA Astrophysics Data System (ADS)

    Falandysz, J.; Lipka, K.

    2003-05-01

    Total mercury concentrations were determined in the fruiting bodies of Fly Agaric Amanita muscaria (L.: FL) Pers. and underlying soil substrate collected from several sites in Poland in 1993-2000 to evaluate mercury status as contaminant and bioindicating features of this species. The samples were collected from the spatially distant sites such as: Zaborski Landscape Park, Mierzeja Wiślana Landscape Park, Wdzydzki Landscape Park, Borecka Forest, Tucholskie Forest, Wieluńska Upland, the communities of Gubin, Manowo, Lubiana and Morag. Total mercury content of caps and stalks of Fly agaric varied widely depending on the sites examined. The range of the mean mercury concentrations for all 17 sites was between 96±10 and 1900±1400 ng/g dry wt for the caps and between 6l±32 and 920±760 ng/g dry wt for the stalks, while between 4.4±3.1 and 150±20 ng/g were noted for soil substrate samples from 9 sites examined. Fly agaric independently of the site examined showed relatively good capacity to accumulate total mercury and BCF values varied between 16±10 and 74±15 for the caps and between 11±8 and 42±10 for the stalks. Nevertheless, relatively high bioconcentration potential of mercury by Fly agaric seems to be specific for that species and under soil mercury concentrations noted no bioindication properties of this mushroom could be observed.

  16. Seasonal variation in the biomass and agar yield from Gracilaria cervicornis and Hydropuntia cornea from Brazil.

    PubMed

    Marinho-Soriano, E; Silva, T S; Moreira, W S

    2001-04-01

    Seasonality of biomass and agar yield from two agarophytes (G. cervicornis and H. cornea) was determined. The biomass from G. cervicornis was higher (390 g m-2) during the dry season and lower during the rainy season (129 g m-2). The data analysis for G. cervicornis revealed a significant seasonal variation (P < 0.05). H. cornea did not show a clear seasonal variation and was present only from March to August. The peak in biomass for this species was recorded in April (383 g m-2) and was significantly different from the other months (P < 0.05). The agar yield for G. cervicornis varied from 11% to 20%, with generally higher values recorded during the dry season. The agar yield showed a highly significant variation (P < 0.001). Agar yield from H. cornea ranged from 29% to 41%, with a peak recorded in June. The results above indicate that H. cornea can be considered a good candidate for commercial use. PMID:11272017

  17. Radiation survival of murine and human melanoma cells utilizing two assay systems: monolayer and soft agar.

    PubMed Central

    Yohem, K. H.; Slymen, D. J.; Bregman, M. D.; Meyskens, F. L.

    1988-01-01

    The radiation response of murine and human melanoma cells assayed in bilayer soft agar and monolayer was examined. Cells from the murine melanoma Cloudman S91 CCL 53.1 cell line and three human melanoma cell strains (C8146C, C8161, and R83-4) developed in our laboratory were irradiated by single dose X-rays and plated either in agar or on plastic. D0 values were the same within 95% confidence intervals for cells from the human melanoma cell strains C8146C, C8161, and R83-4 but were dissimilar for the murine cell line CCL 53.1 Dq values were different for all cells studied. The shape of the survival curve for all four melanomas was not identical for cells assayed in soft agar versus cells grown on plastic. This would indicate that apparent radiosensitivity was influenced by the method of assay although there were no apparent consistent differences between the curves generated by monolayer or bilayer soft agar assays. PMID:3348949

  18. Hyperspectral image reconstruction using RGB color for foodborne pathogen detection on agar plates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reports the latest development of a color vision technique for detecting colonies of foodborne pathogens grown on agar plates with a hyperspectral image classification model that was developed using full hyperspectral data. The hyperspectral classification model depended on reflectance sp...

  19. EFFECT OF IMPACT STRESS ON MICROBIAL RECOVERY ON AN AGAR SURFACE

    EPA Science Inventory

    Microbial stress due to the impaction of microorganisms onto an agar collection surface was studied experimentally. he relative recovery rates of aerosolized Pseudomonas fluorescens and Micrococcus luteus were determined as a function of the impaction velocity by using a moving a...

  20. A Method for Cell Culture and Maintenance of Ammonia-Oxidizing Archaea in Agar Stab.

    PubMed

    Chu, Yeon-Jin; Lee, Jin-Young; Shin, So-Ra; Kim, Geun-Joong

    2015-12-01

    Ammonia oxidizing archaea (AOA) are predominantly found and closely linked with geochemical cycling of nitrogen in non-extreme habitats. However, these strains have mainly been investigated using liquid cultures of enriched cells. Here, we provide an agar stab as a simple and reliable means of cultivating and maintaining AOA. PMID:26543273

  1. Evolutionary consequences of putative intra- and interspecific hybridization in agaric fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agaric fungi of the southern Appalachians including the Great Smoky Mountains National Park are often heterozygous for the rDNA internal transcribed spacer region (ITS) with >42% of collections showing some level of heterozygosity for indels and/or base-pair substitutions. For these collections, int...

  2. Fishmeal extract bile salt lactose agar--a differential medium for enteric bacteria.

    PubMed

    Subbannayya, K; Udayalaxmi, J; Anugraha, M

    2006-08-01

    Fishmeal extract bile salt lactose agar (FEBLA), a new differential medium for enteric bacteria was developed and evaluated for its ability to grow and differentiate lactose fermenters (LF) from non-lactose fermenters (NLF) in comparison with MacConkeys agar. Performance of FEBLA was at par with the latter. On FEBLA medium, the contrast between LF and NLF colonies was pronounced and Klebsiella pneumoniae produced more mucoid colonies than on MacConkeys agar (Hi Media). Unlike MacConkeys agar, a 24 h culture of K. pneumoniae cells on FEBLA were longer and thicker with abundant capsular material around the bacilli. Escherichia coli produced long and thick cells but only after 48h. No change in cell morphology was evident with regard to Salmonella typhi, S. paratyphi A, Shigella flexneri, Pseudomonas aeruginosa, Proteus mirabilis, Proteus vulgaris, Citrobacter koseri and Acinetobacter baumannii. Performance of the medium was controlled using E. coli and S. flexneri. FEBLA is simple, cost effective and may be a suitable alternative in the preliminary identification of enteric bacteria. PMID:16924840

  3. Hyperspectral image reconstruction using RGB color for foodborne pathogen detection on agar plates

    NASA Astrophysics Data System (ADS)

    Yoon, Seung-Chul; Shin, Tae-Sung; Park, Bosoon; Lawrence, Kurt C.; Heitschmidt, Gerald W.

    2014-03-01

    This paper reports the latest development of a color vision technique for detecting colonies of foodborne pathogens grown on agar plates with a hyperspectral image classification model that was developed using full hyperspectral data. The hyperspectral classification model depended on reflectance spectra measured in the visible and near-infrared spectral range from 400 and 1,000 nm (473 narrow spectral bands). Multivariate regression methods were used to estimate and predict hyperspectral data from RGB color values. The six representative non-O157 Shiga-toxin producing Eschetichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) were grown on Rainbow agar plates. A line-scan pushbroom hyperspectral image sensor was used to scan 36 agar plates grown with pure STEC colonies at each plate. The 36 hyperspectral images of the agar plates were divided in half to create training and test sets. The mean Rsquared value for hyperspectral image estimation was about 0.98 in the spectral range between 400 and 700 nm for linear, quadratic and cubic polynomial regression models and the detection accuracy of the hyperspectral image classification model with the principal component analysis and k-nearest neighbors for the test set was up to 92% (99% with the original hyperspectral images). Thus, the results of the study suggested that color-based detection may be viable as a multispectral imaging solution without much loss of prediction accuracy compared to hyperspectral imaging.

  4. MODIFIED AGAR MEDIUM FOR DETECTING ENVIRONMENTAL SALMONELLAE BY THE MOST-PROBABLE-NUMBER METHOD

    EPA Science Inventory

    Salmonellae in the environment remain a potential source of disease. Low numbers of salmonellae have been detected and enumerated from environmental samples by most probable number methods that require careful colony selection from plated agar medium. A modified xylose lysine bri...

  5. Alternative plasticizers for the production of thermo-compressed agar films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One percent agar (% wt) was dissolved in the deep eutectic solvent (DES), (2-hydroxyethyl) trimethylammonium chloride/urea at a 1:2 molar ratio, and successfully Electrospun into nanofibers. An existing electrospinning set-up, operated at 50 deg C, was adapted for use with an ethanol bath to collect...

  6. Investigation of dental alginate and agar impression materials as a brain simulant for ballistic testing.

    PubMed

    Falland-Cheung, Lisa; Piccione, Neil; Zhao, Tianqi; Lazarjan, Milad Soltanipour; Hanlin, Suzanne; Jermy, Mark; Waddell, J Neil

    2016-06-01

    Routine forensic research into in vitro skin/skull/brain ballistic blood backspatter behavior has traditionally used gelatin at a 1:10 Water:Powder (W:P) ratio by volume as a brain simulant. A limitation of gelatin is its high elasticity compared to brain tissue. Therefore this study investigated the use of dental alginate and agar impression materials as a brain simulant for ballistic testing. Fresh deer brain, alginate (W:P ratio 91.5:8.5) and agar (W:P ratio 81:19) specimens (n=10) (11×22×33mm) were placed in transparent Perspex boxes of the same internal dimensions prior to shooting with a 0.22inch caliber high velocity air gun. Quantitative analysis to establish kinetic energy loss, vertical displacement elastic behavior and qualitative analysis to establish elasticity behavior was done via high-speed camera footage (SA5, Photron, Japan) using Photron Fastcam Viewer software (Version 3.5.1, Photron, Japan) and visual observation. Damage mechanisms and behavior were qualitatively established by observation of the materials during and after shooting. The qualitative analysis found that of the two simulant materials tested, agar behaved more like brain in terms of damage and showed similar mechanical response to brain during the passage of the projectile, in terms of energy absorption and vertical velocity displacement. In conclusion agar showed a mechanical and subsequent damage response that was similar to brain compared to alginate. PMID:27131216

  7. Quantification of southern rice black streaked dwarf virus and rice black streaked dwarf virus in the organs of their vector and nonvector insect over time.

    PubMed

    Hajano, Jamal-U-Ddin; Wang, Biao; Ren, Yingdang; Lu, Chuantao; Wang, Xifeng

    2015-10-01

    Southern rice black streaked dwarf virus (SRBSDV) and rice black streaked dwarf virus (RBSDV) are serious rice-infecting reoviruses, which are transmitted by different planthoppers in a persistent propagative manner. In this study, we quantitatively compared the spatial distribution of SRBSDV and RBSDV contents over time in their vector and nonvector insects using real time-PCR. Genome equivalent copies (GEC) were assessed every 2 days from 0 to 14 days after a 3-days acquisition access period (AAP) on infected plants. Results revealed 293.2±21.6 to 404.1±46.4 SRBSDV GEC/ng total RNA in whole body of white-backed planthopper (WBPH, Sogatella furcifera) at day 0 and 12 and 513.5±88.4 to 816.8±110.7 RBSDV GEC/ng total RNA in the whole body of small brown planthopper (SBPH, Laodelphax striatellus) at day 0 and 14, respectively, after 3-days AAP. Highest GEC of both viruses were found in the gut of their respective vectors. Although SRBSDV was detected in the gut of SBPH, it did not spread into the hemolymph or other organs. After an 8-day latent period, the transmission efficiency of SRBSDV and RBSDV by their respective vectors was significantly positively correlated with GEC in the salivary gland (r(2)=0.7808, P=0.0036 and r(2)=0.9351, P<0.0001, respectively, at α=0.05). Together, these results confirm that accumulation of >200 SRBSDV or RBSDV GEC/ng total RNA in the gut of vector, indicated threshold for further spread and the virus content in the salivary gland was significantly correlated with transmission efficiency by their respective vectors. PMID:26116274

  8. Production of microbial medium from defatted brebra (Milletia ferruginea) seed flour to substitute commercial peptone agar

    PubMed Central

    Andualem, Berhanu; Gessesse, Amare

    2013-01-01

    Objective To investigate and optimize microbial media that substitute peptone agar using brebra seed defatted flour. Methods 'Defatted process, inoculums preparation, evaluation of bacterial growth, preparation of cooked and hydrolyzed media and growth turbidity of tested bacteria were determined. Results Two percent defatted flour was found to be suitable concentration for the growth of pathogenic bacteria: Escherichia coli (ATCC 25922) (E. coli), Pseudomonas aeruginosa (ATCC 27853), Salmonella (NCTC 8385) and Shigella flexneri (ATCC 12022) (S. flexneri), while 3% defatted flour was suitable for Staphylococcus aureus (ATCC 25923) (S. aureus). E. coli (93±1) and S. flexneri (524±1) colony count were significantly (P≤0.05) greater in defatted flour without supplement than in supplemented medium. E. coli [(3.72×109±2) CFU/mL], S. aureus [(7.4×109±2) CFU/mL], S. flexneri [(4.03×109±2) CFU/mL] and Salmonella [(2.37×109±1) CFU/mL] in non-hydrolyzed sample were statistically (P≤0.05) greater than hydrolyzed one and commercial peptone agar. Colony count of Salmonella [(4.55×109±3) CFU/mL], S. flexneri [(5.40×109±3) CFU/mL] and Lyesria moncytogenes (ATCC 19116) [(5.4×109±3) CFU/mL] on raw defatted flour agar was significantly (P≤0.05) greater than cooked defatted flour and commercial peptone agar. Biomass of E. coli, S. aureus, Salmonella and Enterococcus faecalis in non-hydrolyzed defatted flour is highly increased over hydrolyzed defatted flour and commercial peptone broth. Conclusions The defatted flour agar was found to be better microbial media or comparable with peptone agar. The substances in it can serve as sources of carbon, nitrogen, vitamins and minerals that are essential to support the growth of microorganisms without any supplements. Currently, all supplements of peptone agar are very expensive in the market. PMID:24075344

  9. Measuring 8–250 ps short pulses using a high-speed streak camera on kilojoule, petawatt-class laser systems

    SciTech Connect

    Qiao, J.; Jaanimagi, P. A.; Boni, R.; Bromage, J.; Hill, E.

    2013-07-15

    Short-pulse measurements using a streak camera are sensitive to space-charge broadening, which depends on the pulse duration and shape, and on the uniformity of photocathode illumination. An anamorphic-diffuser-based beam-homogenizing system and a space-charge-broadening calibration method were developed to accurately measure short pulses using an optical streak camera. This approach provides a more-uniform streak image and enables one to characterize space-charge-induced pulse-broadening effects.

  10. Synchronous time-resolved optical and x-ray emission from simultaneous optical and x-ray streak cameras driven by a master ramp generator

    SciTech Connect

    Balmer, J.E.; Lampert, W.; Roschger, E.; Hares, J.D.; Kilkenny, J.D.

    1985-05-01

    An optical and an x-ray streak camera have been synchronized by driving the deflection plates of both cameras from the same ramp generator. The relative timing of the two cameras was calibrated by running UV light onto the x-ray streak camera. The x-ray streak camera was then used to measure the time of the x-ray emission from a laser plasma with respect to the laser pulse.

  11. Effect of impact stress on microbial recovery on an agar surface.

    PubMed

    Stewart, S L; Grinshpun, S A; Willeke, K; Terzieva, S; Ulevicius, V; Donnelly, J

    1995-04-01

    Microbial stress due to the impaction of microorganisms onto an agar collection surface was studied experimentally. The relative recovery rates of aerosolized Pseudomonas fluorescens and Micrococcus luteus were determined as a function of the impaction velocity by using a moving agar slide impactor operating over a flow rate range from 3.8 to 40 liters/min yielding impaction velocities from 24 to 250 m/s. As a reference, the sixth stage of the Andersen Six-Stage Viable Particle Sizing Sampler was used at its operating flow rate of 28.3 liters/min (24 m/s). At a collection efficiency of close to 100% for the agar slide impactor, an increase in sampling flow rate and, therefore, in impaction velocity produced a significant decline in the percentage of microorganisms recovered. Conversely, when the collection efficiency was less than 100%, greater recovery and lower injury rates occurred. The highest relative rate of recovery (approximately 51% for P. fluorescens and approximately 62% for M. luteus) was obtained on the complete (Trypticase soy agar) medium at 40 and 24 m/s (6.4 and 3.8 liters/min), respectively. M. luteus demonstrated less damage than P. fluorescens, suggesting the hardy nature of the gram-positive strain versus that of the gram-negative microorganism. Comparison of results from the agar slide and Andersen impactors at the same sampling velocity showed that recovery and injury due to collection depends not only on the magnitude of the impaction velocity but also on the degree to which the microorganisms may be embedded in the collection medium.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7747946

  12. Effect of impact stress on microbial recovery on an agar surface.

    PubMed Central

    Stewart, S L; Grinshpun, S A; Willeke, K; Terzieva, S; Ulevicius, V; Donnelly, J

    1995-01-01

    Microbial stress due to the impaction of microorganisms onto an agar collection surface was studied experimentally. The relative recovery rates of aerosolized Pseudomonas fluorescens and Micrococcus luteus were determined as a function of the impaction velocity by using a moving agar slide impactor operating over a flow rate range from 3.8 to 40 liters/min yielding impaction velocities from 24 to 250 m/s. As a reference, the sixth stage of the Andersen Six-Stage Viable Particle Sizing Sampler was used at its operating flow rate of 28.3 liters/min (24 m/s). At a collection efficiency of close to 100% for the agar slide impactor, an increase in sampling flow rate and, therefore, in impaction velocity produced a significant decline in the percentage of microorganisms recovered. Conversely, when the collection efficiency was less than 100%, greater recovery and lower injury rates occurred. The highest relative rate of recovery (approximately 51% for P. fluorescens and approximately 62% for M. luteus) was obtained on the complete (Trypticase soy agar) medium at 40 and 24 m/s (6.4 and 3.8 liters/min), respectively. M. luteus demonstrated less damage than P. fluorescens, suggesting the hardy nature of the gram-positive strain versus that of the gram-negative microorganism. Comparison of results from the agar slide and Andersen impactors at the same sampling velocity showed that recovery and injury due to collection depends not only on the magnitude of the impaction velocity but also on the degree to which the microorganisms may be embedded in the collection medium.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7747946

  13. Use of Dehydrated Agar to Estimate Microbial Water Quality for Horticulture Irrigation.

    PubMed

    Meador, Dustin P; Fisher, Paul R; Guy, Charles L; Harmon, Philip F; Peres, Natalia A; Teplitski, Max

    2016-07-01

    Petrifilms are dehydrated agar culture plates that have been used to quantify colony forming units (CFU) mL of either aerobic bacteria (Petrifilm-AC) or fungus (Petrifilm-YM), depending on substrate composition. Microbes in irrigation systems can indicate biofilm risk and potential clogging of irrigation emitters. The research objective was to compare counts on Petrifilms versus traditional, hydrated-agar plates using samples collected from recirculated irrigation waters and cultures of isolated known species. The estimated count (in CFU mL) from a recirculated irrigation sample after 7 d of incubation on Petrifilm-YM was only 5.5% of the count quantified using sabouraud dextrose agar (SDA) with chloramphenicol after 14 d. In a separate experiment with a known species, Petrifilm-YM did not successfully culture zoospores of . Isolates of viable zoospores were cultured successfully on potato-dextrose agar (PDA), with comparable counts with a vegetable juice medium supplemented with the antibiotics pimaricin, ampicillin, rifamycin, pentochloronitrobenzene and hymexazol (PARP-H). The quantification of pv. Begoniaceae on Petrifilm-AC was not significantly different ( < 0.05) than on PDA, but was lower than on Reasoner and Goldrich agar (R2A) or with a hemocytometer. The current formulation of Petrifilm-YM is unlikely to be a useful monitoring method for plant pathogens in irrigation water because of the inability to successfully culture oomycetes. However, Petrifilm-AC was an effective method to quantify bacteria and can provide an easy-to-use on-farm tool to monitor biofilm risk and microbial density. PMID:27380096

  14. Transgenic RNA interference (RNAi)-derived field resistance to cassava brown streak disease.

    PubMed

    Ogwok, Emmanuel; Odipio, John; Halsey, Mark; Gaitán-Solís, Eliana; Bua, Anton; Taylor, Nigel J; Fauquet, Claude M; Alicai, Titus

    2012-12-01

    Cassava brown streak disease (CBSD), caused by the Ipomoviruses Cassava brown streak virus (CBSV) and Ugandan Cassava brown streak virus (UCBSV), is considered to be an imminent threat to food security in tropical Africa. Cassava plants were transgenically modified to generate small interfering RNAs (siRNAs) from truncated full-length (894-bp) and N-terminal (402-bp) portions of the UCBSV coat protein (ΔCP) sequence. Seven siRNA-producing lines from each gene construct were tested under confined field trials at Namulonge, Uganda. All nontransgenic control plants (n = 60) developed CBSD symptoms on aerial tissues by 6 months after planting, whereas plants transgenic for the full-length ΔCP sequence showed a 3-month delay in disease development, with 98% of clonal replicates within line 718-001 remaining symptom free over the 11-month trial. Reverse transcriptase-polymerase chain reaction (RT-PCR) diagnostics indicated the presence of UCBSV within the leaves of 57% of the nontransgenic controls, but in only two of 413 plants tested (0.5%) across the 14 transgenic lines. All transgenic plants showing CBSD were PCR positive for the presence of CBSV, except for line 781-001, in which 93% of plants were confirmed to be free of both pathogens. At harvest, 90% of storage roots from nontransgenic plants were severely affected by CBSD-induced necrosis. However, transgenic lines 718-005 and 718-001 showed significant suppression of disease, with 95% of roots from the latter line remaining free from necrosis and RT-PCR negative for the presence of both viral pathogens. Cross-protection against CBSV by siRNAs generated from the full-length UCBSV ΔCP confirms a previous report in tobacco. The information presented provides proof of principle for the control of CBSD by RNA interference-mediated technology, and progress towards the potential control of this damaging disease. PMID:22845735

  15. Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems

    SciTech Connect

    Johnston, Mark D.; Oliver, Bryan V.; Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D.; Maron, Yitzhak

    2012-08-15

    This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 {mu}m) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ('hotspot') was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm{sup 2}/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.

  16. Significant seismic streaks corresponding to lithological contrasts in Mesozoic and Paleozoic accretion units, southwest Japan

    NASA Astrophysics Data System (ADS)

    Maeda, S.; Toda, S.; Katao, H.

    2014-12-01

    While high-density seismic streaks are commonly seen in aftershocks of a strike-slip earthquake, significant linear clusters in background seismicity are rare. A typical example of such sustained streaks is observed along the creeping section of the San Andreas fault, in which strain localization associated with frictional heterogeneity takes a responsibility. Here we show other examples from Tamba and Wakayama regions, around Osaka-Kyoto district, where a number of several-to-20-km-long seismic streaks are observed. We explore the role of geologic heterogeneity into the seismicity comparing spatial distribution of earthquakes with geologic structure in both regions, where a significant high background rate of seismicity has been continuously recorded since the mid-1900. Epicenters of numerous small earthquakes are located mainly on the Mesozoic metamorphic rocks and Mesozoic-Paleozoic accretion units, whereas low seismicity is characterized in granite and ultra-mafic rocks. Within the Wakayama seismic zone, in particular, we observe many E-W and ENE-WSW trending dense seismic clusters in hypocenters of Japan Meteorological Agency (JMA) data relocated with the hypo DD algorithm of Waldhauser and Ellsworth (2000). Most of the E-W trending seismic clusters possibly correspond to the E-W trending local scale geologic faults, folds, bedding planes, and schistosity. However, well-determined fault plane solutions by JMA and the National Research Institute for Earth Science and Disaster Prevention (NIED) show NS-trending reverse faults corresponding to EW compression. We further sought the focal mechanisms for smaller earthquakes using waveform data recorded in the SATARN seismic network system of DPRI, Kyoto University. As a result, among the many reverse fault mechanisms, we found some amounts of strike-slip ones, which may associate with the visible EW-trending seismic clusters.

  17. Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems

    NASA Astrophysics Data System (ADS)

    Johnston, Mark D.; Oliver, Bryan V.; Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D.; Maron, Yitzhak

    2012-08-01

    This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 μm) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ("hotspot") was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm2/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.

  18. A Dust Devil Making a Streak and Climbing a Crater Wall

    NASA Technical Reports Server (NTRS)

    2002-01-01

    MGS MOC Release No. MOC2-318, 8 August 2002 [figure removed for brevity, see original site] One of the key elements of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission is to look for and monitor changes taking place on the planet over the course of a second--and, eventually, a third--martian year. MGS is now well into its second Mars year, which will draw to a close in December 2002. Among the changes the MOC has observed are streaks believed to be caused by the passage of dust devils. Thousands of MOC images show these streaks, dozens show that they change over time, but far fewer images have actually captured a dust devil in the act of creating a streak. At the center right of this image (above left) is a dust devil that, on May 21, 2002, was seen climbing the wall of a crater at 4.1oS, 9.5oW. This crater (above right) is in western Terra Meridiani. The dust devil was moving toward the northeast (upper right), leaving behind a dark trail where a thin coating of surficial dust was removed or disrupted as the dust devil advanced. Dust devils most commonly form after noon on days when the martian air is still (that is, when there isn't even a faint breeze). On such days, the ground is better able to heat up the air immediately above the surface. As the warmed near-surface air begins to rise, it also begins to spin, creating a vortex. The spinning column then moves across the surface and picks up loose dust (if any is present). The dust makes the vortex visible and gives it a tornado-like appearance. The dust devil in this image has a very short, dark shadow cast to the right of the bright column; this shadow is short because the sun was nearly overhead.

  19. Effect of Amirkabiria odorastissima mozaffarian on the development and progression of fatty streaks in hypercholesterolemic rabbits.

    PubMed

    Asgary, S; Naderi, Gh; Dashti, Gh; Paknahad, Z

    2004-05-01

    New studies have introduced atherosclerosis as an inflammatory disease. Different factors affect the development of inflammation that can be linked to free radicals, hypertention, diabetes mellitus, genetic changes, hypercholesterolemia and some of the microorganisms. Using anti-inflammatory drugs can be useful in preventing atherosclerosis. Finding drugs from natural sources and without side-effects can be useful. Amirkabiria odoratissima (umbelliferae) is from Iranian fl ora and is used traditionally as an anti-inflammatory drug. This study was designed to assess the effects of this plant on the development and progression of fatty streaks. Male rabbits were fed: (a) rabbit chow; (b) 1% cholesterol diet; (c) cholesterol diet supplemented with the plant; (d) normal diet supplemented with the plant. After 12 weeks, the animals were sacrificed and the aorta, right and left branches of coronary arteries were dissected and histologically processed. Before and after the end of the study, biochemical factors were measured. The amounts of cholesterol, LDL, HDL, triglyceride and fasting blood sugar (FBS) were determined by enzymatic methods, quantitative CRP was determined by turbidimetric methods, malondialdehyde (MDA) and antioxidant capacity were determined by speceterophotometric methods. The results indicate that there is a significant difference between the groups supplemented with herbal medicine and others (p < 0.05) in the mean grade of fatty streak of right and left coronary artery and aorta. At the end of the 12-week period cholesterol, LDL and CRP were significantly reduced in the groups which received herbal medicine (p < 0.05). The data suggests that Amirkabiria odoratissima Mozaffarian has beneficial effects to prevent development of fatty streak; however, further studies are needed to understand the mechanisms whereby this plant exerts its anti-atherosclerotic effects. PMID:15173995

  20. Effect of heat treatment on the performance of tryptose-sulfite-cycloserine agar for enumeration of Clostridium perfringens.

    PubMed Central

    Brodsky, M H; Ciebin, B W

    1979-01-01

    Dissolving dehydrated tryptose-sulfite-cycloserine agar by only boiling or microwaving was found to inhibit Clostridium perfringens colony development in pour plates when compared with C. perfringens recovery in tryptose-sulfite-cycloserine agar prepared by autoclaving. Images PMID:225988

  1. Effect of lignin on water vapor barrier, mechanical, and structural properties of agar/lignin composite films.

    PubMed

    Shankar, Shiv; Reddy, Jeevan Prasad; Rhim, Jong-Whan

    2015-11-01

    Biodegradable composite films were prepared using two renewable resources based biopolymers, agar and lignin alkali. The lignin was used as a reinforcing material and agar as a biopolymer matrix. The effect of lignin concentration (1, 3, 5, and 10wt%) on the performance of the composite films was studied. In addition, the mechanical, water vapor barrier, UV light barrier properties, FE-SEM, and TGA of the films were analyzed. The agar/lignin films exhibited higher mechanical and UV barrier properties along with lower water vapor permeability compared to the neat agar film. The FTIR and SEM results showed the compatibility of lignin with agar polymer. The swelling ratio and moisture content of agar/lignin composite films were decreased with increase in lignin content. The thermostability and char content of agar/lignin composite films increased with increased lignin content. The results suggested that agar/lignin films have a potential to be used as a UV barrier food packaging material for maintaining food safety and extending the shelf-life of the packaged food. PMID:26271435

  2. Differentiating non-0157:H7 STEC serogroups from ground beef plated on agar media by hyperspetral imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: The development of an assay to detect and confirm a positive non-O157:H7 isolate is challenging when mixed morphologically results are obtained from the serogroups growing on Rainbow agar. Rainbow agar is only claimed by the manufacturer to be very specific for E.coli O157:H7 strain...

  3. Impact of dilution on microbial community structure and functional potential: comparison of numerical simulations and batch culture experiments

    NASA Technical Reports Server (NTRS)

    Franklin, R. B.; Garland, J. L.; Bolster, C. H.; Mills, A. L.

    2001-01-01

    A series of microcosm experiments was performed using serial dilutions of a sewage microbial community to inoculate a set of batch cultures in sterile sewage. After inoculation, the dilution-defined communities were allowed to regrow for several days and a number of community attributes were measured in the regrown assemblages. Based upon a set of numerical simulations, community structure was expected to differ along the dilution gradient; the greatest differences in structure were anticipated between the undiluted-low-dilution communities and the communities regrown from the very dilute (more than 10(-4)) inocula. Furthermore, some differences were expected among the lower-dilution treatments (e.g., between undiluted and 10(-1)) depending upon the evenness of the original community. In general, each of the procedures used to examine the experimental community structures separated the communities into at least two, often three, distinct groups. The groupings were consistent with the simulated dilution of a mixture of organisms with a very uneven distribution. Significant differences in community structure were detected with genetic (amplified fragment length polymorphism and terminal restriction fragment length polymorphism), physiological (community level physiological profiling), and culture-based (colony morphology on R2A agar) measurements. Along with differences in community structure, differences in community size (acridine orange direct counting), composition (ratio of sewage medium counts to R2A counts, monitoring of each colony morphology across the treatments), and metabolic redundancy (i.e., generalist versus specialist) were also observed, suggesting that the differences in structure and diversity of communities maintained in the same environment can be manifested as differences in community organization and function.

  4. Direct Shock-Timing Measurements in CH Using Streaked X-Ray Radiography

    NASA Astrophysics Data System (ADS)

    Nilson, P. M.; Lafon, M.; Stillman, C. R.; Mileham, C.; Boni, R.; Boehly, T. R.; Froula, D. H.; Meyerhofer, D. D.

    2014-10-01

    One-dimensional streaked x-ray radiography is used to measure shock coalescence in multishocked plastic. A two-shock system was generated using a ramped drive on the OMEGA EP Laser System. The data show the first shock wave propagating into solid material, followed 2 ns later by the second shock wave. The measured shock trajectories were used to track the system dynamics and determine the shock-coalescence times for different initial shock strengths. The measured shock timings are compared to radiation-hydrodynamic model predictions. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  5. Physics and roller coasters-The Blue Streak at Cedar Point

    NASA Astrophysics Data System (ADS)

    Speers, Robert R.

    1991-06-01

    The use of a roller coaster for external classroom studies of kinematics, forces, dynamics, and energy conservation is discussed. Experimental accelerometer measurements of the vertical forces acting on riders of the Blue Streak at Cedar Point in Sandusky, Ohio are presented. Theoretically, the track profile is used to calculate/predict the vertical forces acting on a rider at the hilltops, valley bottoms, and several other points of interest along the track. Finally the experimental results and theoretical predictions are compared in the context of a rider's experiences.

  6. Capsule Ablator Inflight Performance Measurements Via Streaked Radiography Of ICF Implosions On The NIF*

    NASA Astrophysics Data System (ADS)

    Dewald, E. L.; Tommasini, R.; Mackinnon, A.; MacPhee, A.; Meezan, N.; Olson, R.; Hicks, D.; LePape, S.; Izumi, N.; Fournier, K.; Barrios, M. A.; Ross, S.; Pak, A.; Döppner, T.; Kalantar, D.; Opachich, K.; Rygg, R.; Bradley, D.; Bell, P.; Hamza, A.; Dzenitis, B.; Landen, O. L.; MacGowan, B.; LaFortune, K.; Widmayer, C.; Van Wonterghem, B.; Kilkenny, J.; Edwards, M. J.; Atherton, J.; Moses, E. I.

    2016-03-01

    Streaked 1-dimensional (slit imaging) radiography of 1.1 mm radius capsules in ignition hohlraums was recently introduced on the National Ignition Facility (NIF) and gives an inflight continuous record of capsule ablator implosion velocities, shell thickness and remaining mass in the last 3-5 ns before peak implosion time. The high quality data delivers good accuracy in implosion metrics that meets our requirements for ignition and agrees with recently introduced 2-dimensional pinhole radiography. Calculations match measured trajectory across various capsule designs and laser drives when the peak laser power is reduced by 20%. Furthermore, calculations matching measured trajectories give also good agreement in ablator shell thickness and remaining mass.

  7. Loop-mediated Isothermal Amplification Assay to Rapidly Detect Wheat Streak Mosaic Virus in Quarantined Plants

    PubMed Central

    Lee, Siwon; Kim, Jin-Ho; Choi, Ji-Young; Jang, Won-Cheoul

    2015-01-01

    We developed a loop-mediated isothermal amplification (LAMP) method to rapidly diagnose Wheat streak mosaic virus (WSMV) during quarantine inspections of imported wheat, corn, oats, and millet. The LAMP method was developed as a plant quarantine inspection method for the first time, and its simplicity, quickness, specificity and sensitivity were verified compared to current reverse transcription-polymerase chain reaction (RT-PCR) and nested PCR quarantine methods. We were able to quickly screen for WSMV at quarantine sites with many test samples; thus, this method is expected to contribute to plant quarantine inspections. PMID:26674930

  8. Loop-mediated Isothermal Amplification Assay to Rapidly Detect Wheat Streak Mosaic Virus in Quarantined Plants.

    PubMed

    Lee, Siwon; Kim, Jin-Ho; Choi, Ji-Young; Jang, Won-Cheoul

    2015-12-01

    We developed a loop-mediated isothermal amplification (LAMP) method to rapidly diagnose Wheat streak mosaic virus (WSMV) during quarantine inspections of imported wheat, corn, oats, and millet. The LAMP method was developed as a plant quarantine inspection method for the first time, and its simplicity, quickness, specificity and sensitivity were verified compared to current reverse transcription-polymerase chain reaction (RT-PCR) and nested PCR quarantine methods. We were able to quickly screen for WSMV at quarantine sites with many test samples; thus, this method is expected to contribute to plant quarantine inspections. PMID:26674930

  9. Temporal Characterization of Electron Beam Bunches with a Fast Streak Camera at the JLab FEL Facility

    SciTech Connect

    S. Zhang; S.V. Benson; D. Douglas; D. Hardy; C. Hernandez-Garcia; K. Jordan; G. Neil; Michelle D. Shinn

    2005-08-21

    The design and construction of an optical transport that brings synchrotron radiation from electron bunches to a fast streak camera in a remote area has become a useful tool for online observation of bunch length and stability. This paper will report on the temporal measurements we have done, comparison with simulations, and the on-going work for another imaging optical transport system that will make possible the direct measurement of the longitudinal phase space by measuring the bunch length as a function of energy

  10. Transient electric fields in laser plasmas observed by proton streak deflectometry

    SciTech Connect

    Sokollik, T.; Schnuerer, M.; Ter-Avetisyan, S.; Nickles, P. V.; Risse, E.; Kalashnikov, M.; Sandner, W.; Priebe, G.; Amin, M.; Toncian, T.; Willi, O.; Andreev, A. A.

    2008-03-03

    A novel proton imaging technique was applied which allows a continuous temporal record of electric fields within a time window of several nanoseconds. This 'proton streak deflectometry' was used to investigate transient electric fields of intense ({approx}10{sup 17} W/cm{sup 2}) laser irradiated foils. We found out that these fields with an absolute peak of up to 10{sup 8} V/m extend over millimeter lateral extension and decay at nanosecond duration. Hence, they last much longer than the (approximately picosecond) laser excitation and extend much beyond the laser irradiation focus.

  11. Agar Sediment Test for Assessing the Suitability of Organic Waste Streams for Recovering Nutrients by the Aquatic Worm Lumbriculus variegatus.

    PubMed

    Laarhoven, Bob; Elissen, H J H; Temmink, H; Buisman, C J N

    2016-01-01

    An agar sediment test was developed to evaluate the suitability of organic waste streams from the food industry for recovering nutrients by the aquatic worm Lumbriculus variegatus (Lv). The effects of agar gel, sand, and food quantities in the sediment test on worm growth, reproduction, and water quality were studied. Agar gel addition ameliorated growth conditions by reducing food hydrolysis and altering sediment structure. Best results for combined reproduction and growth were obtained with 0.6% agar-gel (20 ml), 10 g. fine sand, 40 g. coarse sand, and 105 mg fish food (Tetramin). With agar gel, ingestion and growth is more the result of addition of food in its original quality. Final tests with secondary potato starch sludge and wheat bran demonstrated that this test is appropriate for the comparison of solid feedstuffs and suspended organic waste streams. This test method is expected to be suitable for organic waste studies using other sediment dwelling invertebrates. PMID:26937632

  12. Agar Sediment Test for Assessing the Suitability of Organic Waste Streams for Recovering Nutrients by the Aquatic Worm Lumbriculus variegatus

    PubMed Central

    Laarhoven, Bob; Elissen, H. J. H.; Temmink, H.; Buisman, C. J. N.

    2016-01-01

    An agar sediment test was developed to evaluate the suitability of organic waste streams from the food industry for recovering nutrients by the aquatic worm Lumbriculus variegatus (Lv). The effects of agar gel, sand, and food quantities in the sediment test on worm growth, reproduction, and water quality were studied. Agar gel addition ameliorated growth conditions by reducing food hydrolysis and altering sediment structure. Best results for combined reproduction and growth were obtained with 0.6% agar-gel (20 ml), 10 g. fine sand, 40 g. coarse sand, and 105 mg fish food (Tetramin). With agar gel, ingestion and growth is more the result of addition of food in its original quality. Final tests with secondary potato starch sludge and wheat bran demonstrated that this test is appropriate for the comparison of solid feedstuffs and suspended organic waste streams. This test method is expected to be suitable for organic waste studies using other sediment dwelling invertebrates. PMID:26937632

  13. An abbreviated scheme for identification of Yersinia enterocolitica isolated from food enrichments on CIN (cefsulodin-irgasan-novobiocin) agar.

    PubMed

    Devenish, J A; Schiemann, D A

    1981-09-01

    An abbreviated procedure for the biochemical identification of Yersinia enterocolitica isolated from food enrichments on CIN (cefsulodin-irgasan-novobiocin) agar was investigated. A total of 170 colonies resembling Y. enterocolitica in colonial morphology and appearance on CIN agar were selected for identification using API strips. Ninety-three of these isolates were examined with the PathoTec ornithine decarboxylase, Voges-Proskauer, and urease test strips. The PathoTec urease strip alone was adequate for identification of all isolates of Y. enterocolitica. Christensen's urea agar was applied to the remaining 77 isolates and found less specific in the 1 isolate of Enterobacter agglomerans was urease positive along with 10 isolates of Y. enterocolitica. CIN agar is a highly specific medium for isolation of Y. enterocolitica, requiring only Kligler iron agar and urea slants for confirmation of presumptive colonies. PMID:7306881

  14. Wind Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 12 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

    Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

    Windstreaks are features caused by the interaction of wind and topographic landforms. The raised rims and bowls of impact craters causes a complex interaction such that the wind vortex in the lee of the crater can both scour away the surface dust and deposit it back in the center of the lee. If you look closely, you will see evidence of this in a darker 'rim' enclosing a brighter interior.

    Image information: VIS instrument. Latitude 6.9, Longitude 69.4 East (290.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Gluconeogenesis from labeled carbon: estimating isotope dilution

    SciTech Connect

    Kelleher, J.K.

    1986-03-01

    To estimate the rate of gluconeogenesis from steady-state incorporation of labeled 3-carbon precursors into glucose, isotope dilution must be considered so that the rate of labeling of glucose can be quantitatively converted to the rate of gluconeogenesis. An expression for the value of this isotope dilution can be derived using mathematical techniques and a model of the tricarboxylic acid (TCA) cycle. The present investigation employs a more complex model than that used in previous studies. This model includes the following pathways that may affect the correction for isotope dilution: 1) flux of 3-carbon precursor to the oxaloacetate pool via acetyl-CoA and the TCA cycle; 2) flux of 4- or 5-carbon compounds into the TCA cycle; 3) reversible flux between oxaloacetate (OAA) and pyruvate and between OAA and fumarate; 4) incomplete equilibrium between OAA pools; and 5) isotope dilution of 3-carbon tracers between the experimentally measured pool and the precursor for the TCA-cycle OAA pool. Experimental tests are outlined which investigators can use to determine whether these pathways are significant in a specific steady-state system. The study indicated that flux through these five pathways can significantly affect the correction for isotope dilution. To correct for the effects of these pathways an alternative method for calculating isotope dilution is proposed using citrate to relate the specific activities of acetyl-CoA and OAA.

  16. Minimal Coital Dilution in Accra, Ghana

    PubMed Central

    Jenness, Samuel M.; Biney, Adriana A. E.; Ampofo, William Kwabena; Dodoo, F. Nii-Amoo; Cassels, Susan

    2015-01-01

    Background Coital dilution, the reduction in the coital frequency per partner when an additional ongoing partner is added, may reduce the transmission potential of partnership concurrency for HIV and other sexually transmitted infections. Empirical estimates of dilution, especially dilution of sexual acts unprotected by condoms, are needed to inform prevention research. Methods Sexually active adults in Accra, Ghana were recruited in a multi-stage household probability sample. Degree (number of ongoing partners), total acts, and unprotected acts were measured retrospectively for each month in the past year through an event-history calendar. Random effects negative binomial models estimated the association between degree and coital frequency. Results Compared to person-months with a single partner (monogamy), 2.06 times as many total acts and 1.94 times as many unprotected acts occurred in months with 2 partners. In months with 3 partners, 2.90 times as many total acts and 2.39 times as many unprotected acts occurred compared to monogamous months. Total acts but not unprotected acts also declined with partnership duration. Conclusions No dilution was observed for total acts with up to three concurrent partners, but a small amount of dilution was observed for unprotected acts for months with multiple concurrencies. This suggests moderate selective condom use in months with multiple concurrencies. The implications of the observed dilution for future HIV transmission must be investigated with mathematical models. PMID:25622062

  17. Preliminary Performance Measurements for a Streak Camera with a Large-Format Direct-Coupled CCD Readout

    SciTech Connect

    Lerche, R A; McDonald, J W; Griffith, R L; de Dios, G V; Andrews, D S; Huey, A W; Bell, P M; Landen, O L; Jaanimagi, P A; Boni, R

    2004-04-13

    Livermore's ICF Program has a large inventory of optical streak cameras built in the 1970s and 1980s. The cameras are still very functional, but difficult to maintain because many of their parts are obsolete including the original streak tube and image-intensifier tube. The University of Rochester's Laboratory for Laser Energetics is leading an effort to develop a fully automated, large-format streak camera that incorporates modern technology. Preliminary characterization of a prototype camera shows spatial resolution better than 20 lp/mm, temporal resolution of 12 ps, line-spread function of 40 {micro}m (fwhm), contrast transfer ratio (CTR) of 60% at 10 lp/mm, and system sensitivity of 16 CCD electrons per photoelectron. A dynamic range of 60 for a 2 ns window is determined from system noise, linearity and sensitivity measurements.

  18. Frequency-Domain Streak Camera and Tomography for Ultrafast Imaging of Evolving and Channeled Plasma Accelerator Structures

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Reed, Stephen; Dong, Peng; Downer, Michael C.

    2010-11-01

    We demonstrate a prototype Frequency Domain Streak Camera (FDSC) that can capture the picosecond time evolution of the plasma accelerator structure in a single shot. In our prototype Frequency-Domain Streak Camera, a probe pulse propagates obliquely to a sub-picosecond pump pulse that creates an evolving nonlinear index "bubble" in fused silica glass, supplementing a conventional Frequency Domain Holographic (FDH) probe-reference pair that co-propagates with the "bubble". Frequency Domain Tomography (FDT) generalizes Frequency-Domain Streak Camera by probing the "bubble" from multiple angles and reconstructing its morphology and evolution using algorithms similar to those used in medical CAT scans. Multiplexing methods (Temporal Multiplexing and Angular Multiplexing) improve data storage and processing capability, demonstrating a compact Frequency Domain Tomography system with a single spectrometer.

  19. Picosecond-resolved X-ray absorption spectroscopy at low signal contrast using a hard X-ray streak camera

    SciTech Connect

    Adams, Bernhard W.; Rose-Petruck, Christoph; Jiao, Yishuo

    2015-06-24

    A picosecond-resolving hard-X-ray streak camera has been in operation for several years at Sector 7 of the Advanced Photon Source (APS). Several upgrades have been implemented over the past few years to optimize integration into the beamline, reduce the timing jitter, and improve the signal-to-noise ratio. These include the development of X-ray optics for focusing the X-rays into the sample and the entrance slit of the streak camera, and measures to minimize the amount of laser light needed to generate the deflection-voltage ramp. For the latter, the photoconductive switch generating the deflection ramp was replaced with microwave power electronics. With these, the streak camera operates routinely at 88 MHz repetition rate, thus making it compatible with all of the APS fill patterns including use of all the X-rays in the 324-bunch mode. Sample data are shown to demonstrate the performance.

  20. Enumeration of fecal Clostridium perfringens spores in egg yolk-free tryptose-sulfite-cycloserine agar.

    PubMed

    Hauschild, A H; Hilsheimer, R; Griffith, D W

    1974-03-01

    The Shahidi-Ferguson perfringens, tryptose-sulfite-cycloserine (TSC), and egg yolk-free TSC agars have been tested for their suitability to enumerate fecal spores of Clostridium perfringens. When these spores comprised at least 20% of the total anaerobe spores, equally accurate counts were obtained in the three media. With lower ratios of C. perfringens spores, the most accurate counts were obtained in egg yolk-free TSC agar. The median C. perfringens spore count of 60 normal fecal specimens was log 3.4/g. A nonmotile, sulfite- and nitrate-reducing Clostridium, not identifiable with any known clostridial species, was isolated from 14 out of 60 fecal specimans. It was not differentiated from C. perfringens in the nitrite motility test, but could be distinguished by its inability to liquefy gelatin. PMID:4363369

  1. Enumeration of Fecal Clostridium perfringens Spores in Egg Yolk-Free Tryptose-Sulfite-Cycloserine Agar

    PubMed Central

    Hauschild, A. H. W.; Hilsheimer, R.; Griffith, D. W.

    1974-01-01

    The Shahidi-Ferguson perfringens, tryptose-sulfite-cycloserine (TSC), and egg yolk-free TSC agars have been tested for their suitability to enumerate fecal spores of Clostridium perfringens. When these spores comprised at least 20% of the total anaerobe spores, equally accurate counts were obtained in the three media. With lower ratios of C. perfringens spores, the most accurate counts were obtained in egg yolk-free TSC agar. The median C. perfringens spore count of 60 normal fecal specimens was log 3.4/g. A nonmotile, sulfite- and nitrate-reducing Clostridium, not identifiable with any known clostridial species, was isolated from 14 out of 60 fecal specimans. It was not differentiated from C. perfringens in the nitrite motility test, but could be distinguished by its inability to liquefy gelatin. PMID:4363369

  2. Characterization of gelatin-agar based phase separated hydrogel, emulgel and bigel: a comparative study.

    PubMed

    Wakhet, Senggam; Singh, Vinay K; Sahoo, Saikat; Sagiri, Sai Sateesh; Kulanthaivel, Senthilguru; Bhattacharya, Mrinal K; Kumar, Naresh; Banerjee, Indranil; Pal, Kunal

    2015-02-01

    The current study describes the in-depth characterization of agar-gelatin based co-hydrogels, emulgels and bigels to have an insight about the differences in the properties of the formulations. Hydrogels have been extensively studied as vehicle for controlled drug release, whereas, the concept of emulgels and bigels is relatively new. The formulations were characterized by scanning electron microscopy, FTIR spectroscopy, XRD and mechanical properties. The biocompatibility and the ability of the formulations to be used as drug delivery vehicle were also studied. The scanning electron micrographs suggested the presence of internal phases within the agar-gelatin composite matrices of co-hydrogel, emulgel and bigel. FTIR and XRD studies suggested higher crystallinity of emulgels and bigels. Electrical impedance and mechanical stability of the emulgel and the bigel was higher than the hydrogel. The prepared formulations were found to be biocompatible and suitable for drug delivery applications. PMID:25672596

  3. Effect of Soybean Casein Digest Agar Lot on Number of Bacillus stearothermophilus Spores Recovered †

    PubMed Central

    Pflug, I. J.; Smith, Geraldine M.; Christensen, Ronald

    1981-01-01

    In recent years it has become increasingly apparent that Bacillus stearothermophilus spores are affected by various environmental factors that influence the performance of the spores as biological indicators. One environmental factor is the recovery medium. The effect of different lots of commercial soybean casein digest agar on the number of colony-forming units per plate was examined in two series of experiments: (i) several lots of medium from two manufacturers were compared in single experiments, and (ii) paired media experiments with four lots of medium were carried out and yielded three-point survivor curves. The results demonstrate that commercial soybean casein digest agar is variable on a lot-to-lot basis. The variation was lowest when recovering unheated or minimally heated spores and increased greatly with the severity of heating. PMID:16345822

  4. Effect of Soybean Casein Digest Agar Lot on Number of Bacillus stearothermophilus Spores Recovered.

    PubMed

    Pflug, I J; Smith, G M; Christensen, R

    1981-08-01

    In recent years it has become increasingly apparent that Bacillus stearothermophilus spores are affected by various environmental factors that influence the performance of the spores as biological indicators. One environmental factor is the recovery medium. The effect of different lots of commercial soybean casein digest agar on the number of colony-forming units per plate was examined in two series of experiments: (i) several lots of medium from two manufacturers were compared in single experiments, and (ii) paired media experiments with four lots of medium were carried out and yielded three-point survivor curves. The results demonstrate that commercial soybean casein digest agar is variable on a lot-to-lot basis. The variation was lowest when recovering unheated or minimally heated spores and increased greatly with the severity of heating. PMID:16345822

  5. Simultaneous detection and differentiation of Rice black streaked dwarf virus (RBSDV) and Southern rice black streaked dwarf virus (SRBSDV) by duplex real time RT-PCR

    PubMed Central

    2013-01-01

    Background The diseases caused by Rice black streaked dwarf virus (RBSDV) and Southern rice black streaked dwarf virus (SRBSDV) have been occurring epidemically in China and southeastern Asia in recent years. A sensitive, reliable and quantitative method is required to detect and distinguish for RBSDV and SRBSDV in rice and vector insects. Results We developed a sensitive and lineage-specific duplex real time RT-qPCR for detection of RBSDV and SRBSDV in a single or/and double infection in rice samples. The duplex RT-qPCR was optimized using standard samples transcribed by T7 Large Scale RNA Production System in vitro. We developed a reliable system for duplex RT-qPCR, in which its co-efficiency of RBSDV and SRBSDV, were 91.6% and 90.7%, respectively. The coefficient of determination was more than 0.990; the slope of linear equation was −3.542, and −3.567, respectively. Out of 30 samples collected in North and Central China, which were suspected to be infected with these two viruses, 10 samples were detected RBSDV positive by RT-PCR and 12 samples by RT-qPCR. No mixed infections were found. Simultaneously, out of total 60 samples collected from Southern China, which were also suspected to be infected with these two viruses, 41 samples were determined SRBSDV positive by RT-PCR and 47 samples by RT-qPCR. Also in this case no mixed infections were found. The rice genes eEF-1a and UBQ5 were selected as internal controls for quantification assay also performed as good expression stability. Conclusion The duplex RT-qPCR assay provided as a sufficiently sensitive, specific, accurate, reproducible and rapid tool for the detection and differentiation of RBSDV and SRBSDV. The RT-qPCR assay can be used in routine diagnostic of these two viruses in order to study the disease epidemiology in rice crops. PMID:23331990

  6. Slit-mounted LED fiducial system for rotating mirror streak cameras

    SciTech Connect

    Shaw, L.L.; Muelder, S.A.; Rivera, A.T.

    1991-01-01

    We have developed a fiducial system for rotating mirror streak cameras that utilizes light emitting diodes mounted at the slit position of the camera. The diodes are driven to the required high brightness by a unique pulse power circuit designed to provide high voltage, high current pulses 18 nanoseconds in length at a frequency of up to 2.5 megahertz. The availability of super bright light emitting diodes with a wavelength of 630 to 640 nanometers allows us to record fiducial pulses, at streaking speeds in excess of 20mm per microsecond, on all the black and white films commonly used in high speed photography. The time marks on the film record are referenced to the real time of the experiment from a clock-driver that controls the start and frequency of the fiducial pulse train and by three adjustable and discreet blanked fiducials. This paper discusses the development of this system and describes the full setup as used at LLNL. 6 refs., 4 figs.

  7. Synchroscan streak camera imaging at a 15-MeV photoinjector with emittance exchange

    NASA Astrophysics Data System (ADS)

    Lumpkin, A. H.; Ruan, J.; Thurman-Keup, R.

    2012-09-01

    At the Fermilab A0 photoinjector facility, bunch-length measurements of the laser micropulse and the e-beam micropulse have been done in the past with a fast single-sweep module of the Hamamatsu C5680 streak camera with an intrinsic shot-to-shot trigger jitter of 10-20 ps. We have upgraded the camera system with the synchroscan module tuned to 81.25 MHz to provide synchronous summing capability with less than 1.5 ps FWHM trigger jitter and a phase-locked delay box to provide phase stability of ˜1 ps over 10 s of minutes. These steps allowed us to measure both the UV laser pulse train at 263 nm and the e-beam via optical transition radiation (OTR). Due to the low electron beam energies and OTR signals, we typically summed over 50 micropulses with 0.25-1 nC per micropulse. The phase-locked delay box allowed us to assess chromatic temporal effects and instigated another upgrade to an all-mirror input optics barrel. In addition, we added a slow sweep horizontal deflection plug-in unit to provide dual-sweep capability for the streak camera. We report on a series of measurements made during the commissioning of these upgrades including bunch-length and phase effects using the emittance exchange beamline and simultaneous imaging of a UV drive laser component, OTR, and the 800 nm diagnostics laser.

  8. An Optical Streak Diagnostic for Observing Anode-Cathode Plasmas for Radiographic Source Development

    SciTech Connect

    Droemer, Darryl W.; Crain, Marlon D.; Lare, Gregory A.; Bennett, Nichelle L.; Johnston, Mark D.

    2013-06-13

    National Security Technologies, LLC, and Sandia National Laboratories are collaborating in the development of pulsed power–driven flash x-ray radiographic sources that utilize high-intensity electron beam diodes. The RITS 6 (Radiographic Integrated Test Stand) accelerator at Sandia is used to drive a self magnetic pinch diode to produce a Bremsstrahlung x-ray source. The high electric fields and current densities associated with these short A-K gap pinch beam diodes present many challenges in diode development. Plasmas generated at both the anode and cathode affect the diode performance, which is manifested in varying spot (source) sizes, total dose output, and impedance profiles. Understanding the nature of these plasmas including closure rates and densities is important in modeling their behavior and providing insight into their mitigation. In this paper we describe a streak camera–based optical diagnostic that is capable of observing and measuring plasma evolution within the A-K gap. By imaging a region of interest onto the input slit of a streak camera, we are able to produce a time-resolved one-dimensional image of the evolving plasma. Typical data are presented.

  9. Nonlinear response of the photocathode of an x-ray streak camera to UV light

    SciTech Connect

    Kyrala, G.A.; Oro, D.M.; Studebaker, J.K.; Wood, W.M.; Schappert, G.T.; Watts, S.; Fulton, R.D.

    1994-09-01

    We have found that a potassium-iodide photocathode of an x-ray streak camera responds to UV light at {lambda}=308 nm. The photocathode surface work function, 6.5 eV, is larger than the 4 eV energy of the UV photon, hence the source of the response is interesting. We will present results on the response of a transmission type potassium-iodide photocathode to the UV light from a {lambda}308 nm, subpicosecond XeCl laser and from a {lambda}=326 nm HeCd laser. We will test for the nonlinearity of the yield to measure of the number of photons that are needed to be absorbed before a signal is recorded. We will present data on the effect of the UV irradiance on the yield, as well as on the temporal width of the recorded signal. We will give an explanation of the observation and its effect on the dynamic-range response of the streak-camera. We will show that the response is linear with the incident irradiance, up to an incident irradiance of 10{sup 8} W/cm{sup 2} and we will explain the observation.

  10. Automatic Reacquisition of Satellite Positions by Detecting Their Expected Streaks in Astronomical Images

    NASA Astrophysics Data System (ADS)

    Levesque, M.

    Artificial satellites, and particularly space junk, drift continuously from their known orbits. In the surveillance-of-space context, they must be observed frequently to ensure that the corresponding orbital parameter database entries are up-to-date. Autonomous ground-based optical systems are periodically tasked to observe these objects, calculate the difference between their predicted and real positions and update object orbital parameters. The real satellite positions are provided by the detection of the satellite streaks in the astronomical images specifically acquired for this purpose. This paper presents the image processing techniques used to detect and extract the satellite positions. The methodology includes several processing steps including: image background estimation and removal, star detection and removal, an iterative matched filter for streak detection, and finally false alarm rejection algorithms. This detection methodology is able to detect very faint objects. Simulated data were used to evaluate the methodology's performance and determine the sensitivity limits where the algorithm can perform detection without false alarm, which is essential to avoid corruption of the orbital parameter database.

  11. PS-1/S1 picosecond streak camera application for multichannel laser system diagnostics

    SciTech Connect

    Garanin, S G; Bel'kov, S A; Rogozhnikov, G S; Rukavishnikov, N N; Romanov, V V; Voronich, I N; Vorob'ev, N S; Gornostaev, P B; Lozovoi, V I; Shchelev, M Ya

    2014-08-31

    A PS-1/S1 picosecond image-tube streak camera (ITSC) with slit scan (streak camera), developed and manufactured at the General Physics Institute RAS, has been used to measure the spatiotemporal characteristics of ultrashort laser pulses generated by a petawatt-power laser installation 'FEMTO' at the Institute of Laser Physics Research in Sarov. It is found that such a camera is suitable for measuring the spatial and temporal parameters of single laser pulses with an accuracy of about one picosecond. It is shown that the intensity time profile of a train of picosecond pulses may be precisely defined for the pulses separated in time by a few picoseconds. The camera allows the contrast of radiation to be determined with a high (no less than 10{sup 3}) accuracy; spatial distribution of the laser pulses can be measured with an accuracy of tens of microns, and the temporal separation of single laser pulses can be identified with an accuracy of 1 – 1.5 ps. (extreme light fields and their applications)

  12. Attosecond photoelectron streaking with enhanced energy resolution for small-bandgap materials.

    PubMed

    Guggenmos, Alexander; Akil, Ayman; Ossiander, Marcus; Schäffer, Martin; Azzeer, Abdallah Mohammed; Boehm, Gerhard; Amann, Markus-Christian; Kienberger, Reinhard; Schultze, Martin; Kleineberg, Ulf

    2016-08-15

    Attosecond photoelectron streaking spectroscopy allows time-resolved electron dynamics with a temporal resolution approaching the atomic unit of time. Studies have been performed in numerous systems, including atoms, molecules, and surfaces, and the quest for ever higher temporal resolution called for ever wider spectral extent of the attosecond pulses. For typical experiments relying on attosecond pulses with a duration of 200 as, the time-bandwidth limitation for a Gaussian pulse implies a minimal spectral bandwidth larger than 9 eV translating to a corresponding spread of the detected photoelectron kinetic energies. Here, by utilizing a specially tailored narrowband reflective XUV multilayer mirror, we explore experimentally the minimal spectral width compatible with attosecond time-resolved photoelectron spectroscopy while obtaining the highest possible spectral resolution. The validity of the concept is proven by recording attosecond electron streaking traces from the direct semiconductor gallium arsenide (GaAs), with a nominal bandgap of 1.42 eV at room temperature, proving the potential of the approach for tracking charge dynamics also in these technologically highly relevant materials that previously have been inaccessible to attosecond science. PMID:27519070

  13. Attosecond time-resolved streaked photoemission from Mg-covered W(110) surfaces

    NASA Astrophysics Data System (ADS)

    Liao, Qing; Thumm, Uwe

    2015-09-01

    We formulate a quantum-mechanical model for infrared-streaked photoelectron (PE) emission by ultrashort extreme ultraviolet (XUV) pulses from an adsorbate-covered metal surface, exposing the influence of microscopic PE dispersion in substrate and adsorbate on the interpretation of streaked photoemission spectra and photoemission time delays. We validate this numerical model first by reproducing measured relative photoemission delays (a) between valence-band and 2 p -core-level (CL) PEs emitted from clean Mg(0001) surfaces and (b) between conduction-band (CB) and 4 f -CL PEs from clean W(110) surfaces at two XUV-pulse central photon energies. Next, applying this model to ultrathin Mg adsorbate layers on W(110) substrates, we reproduce (i) the measured nonmonotonic dependence of relative photoemission delays between CB and Mg (2 p ) PEs and (ii) the monotonic dependence of relative delays between W (4 f ) and Mg (2 p ) PEs in a recent experiment [S. Neppl et al., Nature (London) 517, 342 (2015), 10.1038/nature14094].

  14. Single-shot visualization of evolving laser wakefields using an all-optical streak camera

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Tsai, Hai-En; Zhang, Xi; Pai, Chih-Hao; Chang, Yen-Yu; Zgadzaj, Rafal; Wang, Xiaoming; Khudik, Vladimir; Shvets, Gennady; Downer, Michael

    2014-10-01

    We visualize ps-time-scale evolution of an electron density bubble, a wake structure created in atmospheric density plasma by an intense ultrashort laser pulse, from the phase ``streak'' that the bubble imprints onto a probe pulse that crosses its path obliquely. Phase streaks, recovered in one shot using frequency-domain interferometry, reveal formation, propagation and coalescence of the bubble within a 3 mm long ionized helium gas target. 3D particle-in-cell (PIC) simulations validate the observed density-dependent bubble evolution, and correlate it with generation of a quasi-monoenergetic ~100 MeV electron beam. The results provide a basis for understanding optimized electron acceleration at plasma density ne ~2e19 cm-3, at which the bubble formed and persisted until the jet exit, enabling acceleration over a distance slightly exceeding the dephasing length. In contrast, at lower density, electrons accelerated inefficiently due to weak laser self-focusing and late bubble formation. At higher density, overly strong self-focusing also led to low quality electrons due to early bubble formation and strong dephasing. Bubble coalescence due to beam loading further degraded electron acceleration. This work was supported by DOE grants DESC0011617 and DE-SC0007889 and by the NSF-DOE Partnership in Plasma Science program.

  15. Mapping the distribution of maize streak virus genotypes across the forest and transition zones of Ghana.

    PubMed

    Oppong, Allen; Offei, Samuel K; Ofori, Kwadwo; Adu-Dapaah, Hans; Lamptey, Joseph N L; Kurenbach, Brigitta; Walters, Matthew; Shepherd, Dionne N; Martin, Darren P; Varsani, Arvind

    2015-02-01

    Throughout sub-Saharan Africa, maize streak virus strain A (MSV-A), the causal agent of maize streak disease (MSD), is an important biological constraint on maize production. In November/December 2010, an MSD survey was carried out in the forest and transition zones of Ghana in order to obtain MSV-A virulence sources for the development of MSD-resistant maize genotypes with agronomic properties suitable for these regions. In 79 well-distributed maize fields, the mean MSD incidence was 18.544 % and the symptom severity score was 2.956 (1 = no symptoms and 5 = extremely severe). We detected no correlation between these two variables. Phylogenetic analysis of cloned MSV-A isolates that were fully sequenced from samples collected in 51 of these fields, together with those sampled from various other parts of Africa, indicated that all of the Ghanaian isolates occurred within a broader cluster of West African isolates, all belonging to the highly virulent MSV-A1 subtype. Besides being the first report of a systematic MSV survey in Ghana, this study is the first to characterize the full-genome sequences of Ghanaian MSV isolates. The 51 genome sequences determined here will additionally be a valuable resource for the rational selection of representative MSV-A variant panels for MSD resistance screening. PMID:25344899

  16. The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa

    PubMed Central

    Mohammed, I. U.; Abarshi, M. M.; Muli, B.; Hillocks, R. J.; Maruthi, M. N.

    2012-01-01

    The genetic and symptom diversity of six virus isolates causing cassava brown streak disease (CBSD) in the endemic (Kenya, Mozambique, and Tanzania) and the recently affected epidemic areas (Uganda) of eastern Africa was studied. Five cassava varieties; Albert, Colombian, Ebwanateraka, TMS60444 (all susceptible) and Kiroba (tolerant) were graft inoculated with each isolate. Based on a number of parameters including the severity of leaf and root symptoms, and the extent of virus transmission by grafting, the viruses were classified as either severe or relatively mild. These results were further confirmed by the mechanical inoculation of 13 herbaceous hosts in which the virulent isolates caused plant death in Nicotiana clevelandii and N. benthamiana whereas the milder isolates did not. Phylogenetic analysis of complete coat protein gene sequences of these isolates together with sequences obtained from 14 other field-collected samples from Kenya and Zanzibar, and reference sequences grouped them into two distinct clusters, representing the two species of cassava brown streak viruses. Put together, these results did not suggest the association of a hypervirulent form of the virus with the current CBSD epidemic in Uganda. Identification of the severe and milder isolates, however, has further implications for disease management and quarantine requirements. PMID:22454639

  17. A Method for Analysing High Resolution, Time Domain, Streak Camera Calibration Data

    SciTech Connect

    Silbernagel, C

    2004-07-02

    Many experiments that require a highly accurate continuous time history of photon emission incorporate streak cameras into their setup. Nonlinear recordings both in time and spatial displacement are inherent to streak camera measurements. These nonlinearities can be attributed to sweep rate electronics, curvature of the electron optics, the magnification, and resolution of the electron optics. These nonlinearities are systematic; it has been shown that a short pulse laser source, an air-spaced etalon of known separation, and a defined spatial resolution mask can provide the proper image information to correct for the resulting distortion. A set of Interactive Data Language (IDL){sup 1} software routines were developed to take a series of calibration images showing temporally and spatially displaced points, and map these points from a nonlinear to a linear space-time resultant function. This correction function, in combination with standardized image correction techniques, can be applied to experiment data to minimize systematic errors and improve temporal and spatial resolution measurements.

  18. PS-1/S1 picosecond streak camera application for multichannel laser system diagnostics

    NASA Astrophysics Data System (ADS)

    Garanin, S. G.; Bel'kov, S. A.; Rogozhnikov, G. S.; Rukavishnikov, N. N.; Romanov, V. V.; Voronich, I. N.; Vorob'ev, N. S.; Gornostaev, P. B.; Lozovoi, V. I.; Shchelev, M. Ya

    2014-08-01

    A PS-1/S1 picosecond image-tube streak camera (ITSC) with slit scan (streak camera), developed and manufactured at the General Physics Institute RAS, has been used to measure the spatiotemporal characteristics of ultrashort laser pulses generated by a petawatt-power laser installation 'FEMTO' at the Institute of Laser Physics Research in Sarov. It is found that such a camera is suitable for measuring the spatial and temporal parameters of single laser pulses with an accuracy of about one picosecond. It is shown that the intensity time profile of a train of picosecond pulses may be precisely defined for the pulses separated in time by a few picoseconds. The camera allows the contrast of radiation to be determined with a high (no less than 103) accuracy; spatial distribution of the laser pulses can be measured with an accuracy of tens of microns, and the temporal separation of single laser pulses can be identified with an accuracy of 1 - 1.5 ps.

  19. Gas-phase lifetimes of nucleobase analogues by picosecond pumpionization and streak techniques.

    PubMed

    Blaser, Susan; Frey, Hans-Martin; Heid, Cornelia G; Leutwyler, Samuel

    2014-01-01

    The picosecond (ps) timescale is relevant for the investigation of many molecular dynamical processes such as fluorescence, nonradiative relaxation, intramolecular vibrational relaxation, molecular rotation and intermolecular energy transfer, to name a few. While investigations of ultrafast (femtosecond) processes of biological molecules, e.g. nucleobases and their analogues in the gas phase are available, there are few investigations on the ps time scale. We have constructed a ps pump-ionization setup and a ps streak camera fluorescence apparatus for the determination of lifetimes of supersonic jet-cooled and isolated molecules and clusters. The ps pump-ionization setup was used to determine the lifetimes of the nucleobase analogue 2-aminopurine (2AP) and of two 2AP˙(H2O)n water cluster isomers with n=1 and 2. Their lifetimes lie between 150 ps and 3 ns and are strongly cluster-size dependent. The ps streak camera setup was used to determine accurate fluorescence lifetimes of the uracil analogue 2-pyridone (2PY), its self-dimer (2PY)2, two isomers of its trimer (2PY)3 and its tetramer (2PY)4, which lie in the 7-12 ns range. PMID:24983611

  20. Cytotoxicity of ferrite particles by MTT and agar diffusion methods for hyperthermic application

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Hyun; Lee, Se-Ho; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Shim, In-Bo; Lee, Yong-Keun

    2005-05-01

    We investigated the cytotoxicity of the prepared various ferrites (Fe-, Li-, Ni/Zn/Cu-, Ba-, Sr-, Co-, Co/Ni-ferrites) using MTT assay as well as agar diffusion method. Their cytotoxicity was compared with that of alginate-encapsulated ferrites. In the MTT assay, Fe 3O 4 and SrFe 12O 19 ferrite showed the highest cell viability of 90%. Alginate-encapsulated Ba-ferrite was ranked mildly cytotoxic, whereas their ferrite particles were ranked cytotoxic.

  1. Co-precipitation with PVP and Agar to Improve Physicomechanical Properties of Ibuprofen

    PubMed Central

    Maghsoodi, Maryam; Kiafar, Farhad

    2013-01-01

    Objective(s) : Ibuprofen is a problematic drug in tableting due to its viscoelastic properties. Additionally its high cohesivity results in low flowability. In this study, co-precipitation of ibuprofen with varying concentration of agar and PVP to optimize properties of Ibuprofen was carried out. Materials and Methods: Co-precipitates of ibuprofen- PVP or agar were prepared by solvent evaporation technique under vacuum condition. Differential scanning calorimetry (DSC), X -ray diffraction of powder (XRDP) and FT-IR spectroscopy were used to investigate the solid state characteristics of the co-precipitates. The dissolution behavior, flowability, particle size and compaction properties of various batches were also studied. Results: Co-precipitation of drug with agar led to a change in habit from needle to plate shape crystals, while drug –PVP co-precipitates had agglomerated structure and consisted of numerous crystals which had been aggregated together. The co-precipitates showed improved flow properties compared with ibuprofen alone. Precipitation of ibuprofen with these additives led to modification in the dissolution of the drug. Agar in 1% w/w improved slightly the dissolution rate of drug while PVP had a negative impact and led to reduction in the dissolution rate of drug to less than that of pure drug. The all obtained co-precipitates exhibited significantly improved tableting behavior compared with drug crystals alone. This may be due to this fact that, the polymer covering the drug particles increases and changes the nature of the surface area available for interparticulate bonds between particles. DSC, XRDP and FT-IR experiments showed that drug particles, in co-precipitates samples, did not undergo polymorphic modifications. Conclusion: The study highlights the influence of polymeric additives on crystallization process leading to modified performance. PMID:24250942

  2. Co-precipitation with PVP and Agar to Improve Physicomechanical Properties of Ibuprofen

    PubMed Central

    Maghsoodi, Maryam; Kiafar, Farhad

    2013-01-01

    Objective(s) : Ibuprofen is a problematic drug in tableting due to its viscoelastic properties. Additionally its high cohesivity results in low flowability. In this study, co-precipitation of ibuprofen with varying concentration of agar and PVP to optimize properties of Ibuprofen was carried out. Materials and Methods: Co-precipitates of ibuprofen- PVP or agar were prepared by solvent evaporation technique under vacuum condition. Differential scanning calorimetry (DSC), X -ray diffraction of powder (XRDP) and FT-IR spectroscopy were used to investigate the solid state characteristics of the co-precipitates. The dissolution behavior, flowability, particle size and compaction properties of various batches were also studied. Results: Co-precipitation of drug with agar led to a change in habit from needle to plate shape crystals, while drug –PVP co-precipitates had agglomerated structure and consisted of numerous crystals which had been aggregated together. The co-precipitates showed improved flow properties compared with ibuprofen alone. Precipitation of ibuprofen with these additives led to modification in the dissolution of the drug. Agar in 1% w/w improved slightly the dissolution rate of drug while PVP had a negative impact and led to reduction in the dissolution rate of drug to less than that of pure drug. The all obtained co-precipitates exhibited significantly improved tableting behavior compared with drug crystals alone. This may be due to this fact that, the polymer covering the drug particles increases and changes the nature of the surface area available for interparticulate bonds between particles. DSC, XRDP and FT-IR experiments showed that drug particles, in co-precipitates samples, did not undergo polymorphic modifications. Conclusion: The study highlights the influence of polymeric additives on crystallization process leading to modified performance. PMID:24250936

  3. Alternative plasticizers for the production of thermo-compressed agar films.

    PubMed

    Sousa, Ana M M; Souza, Hiléia K S; Liu, LinShu; Gonçalves, Maria P

    2015-05-01

    Agar films were produced by thermo-compression using choline chloride (ChCl) as a plasticizer with urea. The three solid components were mixed together with the salt and urea (minor components) added to agar (main component) according to a fixed mass ratio of, respectively, 1.16:1:5. A central composite rotatable design (CCRD) with three parameters, 2(3), was used to evaluate the effects of temperature (X1; °C), time (X2; min) and applied load (X3; kN) of heat-pressing on the maximum tensile strength (TS) of the films (Y; MPa). Mixtures of urea and agar prepared at a mass ratio of 1:5 did not form homogeneous films suggesting the important plasticizing role of the salt. Heat-pressing the mixtures at more draconian conditions led to much darker and opaque films, with better mechanical resistance (higher values of TS). The most resistant film (∼ 15 MPa) was obtained at 140°C, 20 min and 176 kN. Selected films, including the optimal, showed similar water sorption profiles and close values of water vapor permeability (∼ 2.5-3.7 × 10(-9)gm(-1)s(-1)Pa(-1)). The fracture behavior and mechanical properties of the films were greatly affected by additional water plasticization when the films were stored at different conditions of relative humidity. PMID:25727746

  4. Simulation of Bacillus subtilis biofilm growth on agar plate by diffusion–reaction based continuum model

    NASA Astrophysics Data System (ADS)

    Zhang, Xianlong; Wang, Xiaoling; Nie, Kai; Li, Mingpeng; Sun, Qingping

    2016-08-01

    Various species of bacteria form highly organized spatially-structured aggregates known as biofilms. To understand how microenvironments impact biofilm growth dynamics, we propose a diffusion–reaction continuum model to simulate the formation of Bacillus subtilis biofilm on an agar plate. The extended finite element method combined with level set method are employed to perform the simulation, numerical results show the quantitative relationship between colony morphologies and nutrient depletion over time. Considering that the production of polysaccharide in wild-type cells may enhance biofilm spreading on the agar plate, we inoculate mutant colony incapable of producing polysaccharide to verify our results. Predictions of the glutamate source biofilm’s shape parameters agree with the experimental mutant colony better than that of glycerol source biofilm, suggesting that glutamate is rate limiting nutrient for Bacillus subtilis biofilm growth on agar plate, and the diffusion-limited is a better description to the experiment. In addition, we find that the diffusion time scale is of the same magnitude as growth process, and the common-employed quasi-steady approximation is not applicable here.

  5. Evaluation of cephamycins as supplements to selective agar for detecting Campylobacter spp. in chicken carcass rinses.

    PubMed

    Chon, Jung-Whan; Kim, Young-Ji; Kim, Hong-Seok; Kim, Dong-Hyeon; Kim, Hyunsook; Song, Kwang-Young; Sung, Kidon; Seo, Kun-Ho

    2016-04-16

    Although cefoperazone is the most commonly used antibiotic in Campylobacter-selective media, the distribution of cefoperazone-resistant bacteria such as extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is increasing. Here we evaluated the potential of cephamycins for use as supplements to improve modified charcoal-cefoperazone-deoxycholate agar (mCCDA) by replacing cefoperazone with the same concentrations (32 mg/L) of cefotetan (modified charcoal-cefotetan-deoxycholate agar, mCCtDA) and cefoxitin (modified charcoal-cefoxitin-deoxycholate agar, mCCxDA). In chicken carcass rinse samples, the number of mCCDA plates detecting for Campylobacter (18/70, 26%) was significantly lower than that of mCCtDA (42/70, 60%) or mCCxDA plates (40/70, 57%). The number of mCCDA plates (70/70, 100%) that were contaminated with non-Campylobacter species was significantly higher than that of mCCtDA (20/70, 29%) or mCCxDA plates (21/70, 30%). The most common competing species identified using mCCDA was ESBL-producing E. coli, while Pseudomonas species frequently appeared on mCCtDA and mCCxDA. PMID:26915052

  6. Simulation of Bacillus subtilis biofilm growth on agar plate by diffusion-reaction based continuum model.

    PubMed

    Zhang, Xianlong; Wang, Xiaoling; Nie, Kai; Li, Mingpeng; Sun, Qingping

    2016-01-01

    Various species of bacteria form highly organized spatially-structured aggregates known as biofilms. To understand how microenvironments impact biofilm growth dynamics, we propose a diffusion-reaction continuum model to simulate the formation of Bacillus subtilis biofilm on an agar plate. The extended finite element method combined with level set method are employed to perform the simulation, numerical results show the quantitative relationship between colony morphologies and nutrient depletion over time. Considering that the production of polysaccharide in wild-type cells may enhance biofilm spreading on the agar plate, we inoculate mutant colony incapable of producing polysaccharide to verify our results. Predictions of the glutamate source biofilm's shape parameters agree with the experimental mutant colony better than that of glycerol source biofilm, suggesting that glutamate is rate limiting nutrient for Bacillus subtilis biofilm growth on agar plate, and the diffusion-limited is a better description to the experiment. In addition, we find that the diffusion time scale is of the same magnitude as growth process, and the common-employed quasi-steady approximation is not applicable here. PMID:27434099

  7. Agar Plate Method for Detection and Enumeration of Alkylbenzenesulfonate-Degrading Microorganisms

    PubMed Central

    Ohwada, Kouichi

    1975-01-01

    A simple method for detection and enumeration of alkylbenzenesulfonate (ABS)-degrading microorganisms by using agar plates was developed and used in microbiological studies of coastal marine and polluted river waters. The method depends upon the color responses of neutral red in alkaline medium. Neutral red changes from pink, when it enters into ABS micelles, to yellow, when the ABS is degraded, and does not form micelles. When neutral red-tris(hydroxymethyl)-aminomethane buffer solution and then cationic surfactant solution were sprayed onto the agar surface of ABS-nutrient agar cultures, transparent haloes appeared around the colonies of ABS-degrading microorganisms against a pink background. Viable counts of ABS-degrading bacteria isolated from both seawater and freshwater environments were considerably higher in polluted waters than in less polluted areas. Viable counts of ABS-degrading bacteria averaged 1.5 × 105/ml in samples from the surface water of polluted Tokyo Bay and 3.0 × 104/ml in samples from the surface water of polluted Tamagawa River but were fewer in number in samples from less polluted waters. Images PMID:234155

  8. A supplemented soft agar chemotaxis assay demonstrates the Helicobacter pylori chemotactic response to zinc and nickel

    PubMed Central

    Sanders, Lisa; Andermann, Tessa M.

    2013-01-01

    Directed motility, or chemotaxis, is required for Helicobacter pylori to establish infection in the stomach, although the full repertoire of this bacterium’s chemotactic responses is not yet known. Here we report that H. pylori responds to zinc as an attractant and nickel as a repellent. To reach this conclusion, we employed both a temporal chemotaxis assay based on bacterial reversals and a supplemented soft agar spatial assay. We refined the temporal assay using a previously described chemorepellent, acid, and found that H. pylori requires rich media with serum to maintain optimal swimming motility. Surprisingly, we found that some strains respond to acid as an attractant, and that the TlpC chemoreceptor correlated with whether acid was sensed as an attractant or repellent. Using this same assay, we detected weak repellent responses to nickel and copper, and a varied response to zinc. We thus developed an alternative spatial chemotactic assay called the supplemented soft agar assay, which utilizes soft agar medium supplemented with the test compound. With Escherichia coli, the attractant serine slowed overall bacterial migration, while the repellent nickel increased the speed of overall migration. In H. pylori we detected slowed migration with doubled tryptone media, as well as zinc, consistent with an attractant response. In contrast, nickel increased migration, consistent with repulsion. PMID:23139399

  9. How do microorganisms influence trace element uptake by plants? Screening in an agar model rhizosphere.

    NASA Astrophysics Data System (ADS)

    Marchetti, M.; Robinson, B. H.; Evangelou, M. W. H.; Vachey, A.; Schwitzguebel, J. P.; Bernier-Latmani, R.; Schulin, R.

    2009-04-01

    Trace elements (TE) are essential for humans and plants, but they may be toxic if their concentration is too high. For this reason, the management of TE in soils is very important. In some cases it may be necessary to increase the uptake of nutrients or TE by plants, for example in a biofortification perspective. Conversely, in some other cases TE uptake by plants should be decreased, for instance to avoid heavy metals entering the food chain via edible crops. Microorganisms living in the rhizosphere affect trace element (TE) uptake by plants. However, due to the complexity of this space and the variety of microorganisms that occur there, it is difficult to isolate the effect of any particular strain. To overcome this hurdle, we developed a system in which we grew plants under sterile conditions in agar and inoculated their rhizosphere with a single, well-defined microbial strain. For many years, agar has been used as a growth substrate for microorganisms and plant tissues. It is cheap, easy to use, and can be autoclaved to ensure its sterility. Because of its widespread use, an experiment conducted using this substrate can be reproduced under the same conditions in any laboratory. In contrast to soil, there is little interaction between the trace elements and the agar matrix. There are many studies investigating the influence of microorganisms on TE uptake by plants. However, so far only a small variety of microorganisms has been tested on few plant species. Therefore, the first objective of our research was to develop a method to rapidly screen a large variety of microorganisms on various plant species. Once this goal was achieved, we sought to study the effect of single, well-defined microbial strains on TE uptake by sunflower and wheat. The substrate for plants growth was a 10% agar solution prepared with modified Hoagland's solution and a TE solution containing 1 mg/kg Pb and molar equivalents of Cu, Ni and Zn. The agar solution was autoclaved and poured into

  10. Development and characterisation of an agar--polyvinyl alcohol blend hydrogel.

    PubMed

    Lyons, John G; Geever, Luke M; Nugent, Michael J D; Kennedy, James E; Higginbotham, Clement L

    2009-10-01

    Numerous authors have reported on hydrogel technologies providing products suitable for applications in biomedical, personal care as well as in nano-sensor applications. Hydrogels fabricated from single polymers have been extensively investigated. However, in many cases a single polymer alone cannot meet divergent demands in terms of both properties and performance. In this work, hydrogels were prepared by physically blending the natural polymer agar with polyvinyl alcohol in varying ratios to produce a new biosynthetic polymer applicable for a variety of purposes. Hydrogen bonding was observed to take place between the polyvinyl alcohol and the agar molecules in the composite materials leading to changes in the thermal, mechanical and swelling characteristics of the composite hydrogels. The composite hydrogels exhibited a slightly higher melting temperature than pure agar (116.81 degrees C). Irreversible compressive damage was found to occur at lower strain levels during compression testing of the dehydrated samples consisting of higher PVOH concentrations. Rheological analysis of hydrated sample revealed G' values of between 5000 and 10,000 Pa for the composite blends, with gels containing higher PVOH percentages exhibiting poorer mechanical strength. PMID:19627855

  11. The dynamic nature and spectral characteristics of low-albedo slope streaks on Mars and their possible hydrologic implications

    NASA Astrophysics Data System (ADS)

    Mushkin, A.; Stillman, D. E.; Gillespie, A. R.; Montgomery, D. R.; Schreiber, B. C.; Hibbitts, C.

    2014-12-01

    Low-albedo down-slope streaks that form repeatedly within weekly time-scales and subsequently fade over seasonal to decadal periods are commonly observed in the tropical and mid-latitudes of Mars. 'Dry' mass-wasting processes vs. 'wet' modification of the surface by aqueous phases are the mechanisms typically considered to explain their formation. Recently, high frequency HiRISE image time-series of seasonal recurrence, incremental growth and fading of small (meter-decameter scale) slope streaks, also termed 'recurring slope lineae' (RSL), have been presented in support of a 'wet' origin likely associated with brine seepage. Here, we present new results that demonstrate comparable recurrence, incremental growth and fading characteristics over yearly time-scales for decameter-kilometer scale low-albedo slope-streaks in Lycus Sulci, Amazonis Planitia and Arabia Terra. These dynamic characteristics support the previous association of low-albedo slope streaks with brine seepage based on their geomorphic and spectral relations with surrounding unaffected slopes. Low-albedo slope streaks are typically not associated with detectable erosion or terminal, down-slope depositional activity at the resolution of 25 cm/pixel HiRISE images. CRISM observations consistently indicate that darkened slope-streak surfaces are spectrally enriched in FeOx and are void of detectable water/ice spectral absorption bands. Thus, the liquid seeps considered for the formation of meter to kilometer scale slope streaks are likely low-volume transient events that evaporate and/or freeze and sublime leaving behind a meta-stable dry precipitate that 'stains' the surface dark and may provide insights into the possible composition of such brines. Slope streak formation through a 'wet' brine seepage mechanism supports the possible presence of pressurized sub-surface aquifers that may be released via faults or cracks able to produce recurring transient discharge events during favorably warm daily

  12. Isolation of Clostridium difficile from faecal specimens--a comparison of chromID C. difficile agar and cycloserine-cefoxitin-fructose agar.

    PubMed

    Carson, Kerry C; Boseiwaqa, Lusiana V; Thean, Sara K; Foster, Niki F; Riley, Thomas V

    2013-09-01

    The culture of toxigenic Clostridium difficile from stool specimens is still seen as the gold standard for the laboratory diagnosis of C. difficile infection (CDI). bioMérieux have released ChromID Cdiff chromogenic agar (CDIF) for the isolation and identification of C. difficile in 24 h. In this study, we compared CDIF to pre-reduced cycloserine-cefoxitin-fructose agar with sodium taurocholate (TCCFA) in the examination of glutamate dehydrogenase-positive faecal specimens that were either GeneOhm positive or negative, using direct culture or culture following alcohol shock. Direct culture on CDIF had a sensitivity of 100 % and recovery of 94 % while for TCCFA these were 87 % and 82 %, respectively. For GeneOhm-positive alcohol-shocked faecal samples, sensitivity and recovery on CDIF was similar to direct culture while on TCCFA they were about 10 % higher. For direct culture, there was a significant difference between growth on CDIF at 24 h and TCCFA at 48 h (P = 0.001) and between the two media at 48 h (P<0.001). A total of 142 strains of C. difficile were recovered in pure culture from all GeneOhm-positive samples used in this study and 11 (7.7 %) of these were A(-)B(-)CDT(-) and may represent mixed infections of toxigenic and non-toxigenic C. difficile. The most dominant ribotype was UK 014 (14.7 %) followed by 002 (11.9 %) and 020 (11.9 %), and 36 % of toxigenic isolates, including an A(-)B(+)CDT(-) strain, could not be assigned a UK ribotype. CDIF outperformed pre-reduced TCCFA by negating the need for alcohol shock treatment and by giving a time saving of 24 h in the isolation of C. difficile. CDIF plates were also more selective than TCCFA and C. difficile colonies were easy to identify and subculture prior to strain typing. PMID:23579394

  13. Quantification of Maize Fine Streak Virus Genomic and Positive-sense RNAs in Infected Maize Reveals High Level Accumulation of ORF 3 and 4 MFSV Transcripts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantification of Maize fine streak virus genomic and positive-sense RNAs in infected maize reveals high level accumulation of ORF 3 and 4 MFSV transcripts. We improved methods to analyze RNA produced by Maize fine streak virus (MVSF) within infected maize tissue using real-time RT-qPCR. We designe...

  14. AgarTrap-mediated genetic transformation using intact gemmae/gemmalings of the liverwort Marchantia polymorpha L.

    PubMed

    Tsuboyama-Tanaka, Shoko; Kodama, Yutaka

    2015-03-01

    The dioecious liverwort, Marchantia polymorpha L., is an emerging model plant. Various molecular biological techniques have been optimized for M. polymorpha for the past several years, and recently we reported a simplified Agrobacterium-mediated transformation method using sporelings (immature thalli from spores) of M. polymorpha. This method, termed AgarTrap (Agar-utilized Transformation with Pouring Solutions), completed by exchanging appropriate solutions on a single Petri dish to produce a sufficient number of independent transgenic sporelings. However, because spores are produced by crosses between males and females, the genetic backgrounds of resulting transgenic sporelings are not uniform. To easily produce transgenic liverworts with a uniform genetic background using AgarTrap, we developed an AgarTrap-mediated transformation method using intact gemmae/gemmalings produced by asexual reproduction. Using AgarTrap with male and female gemmae/gemmalings produced a sufficient number of independent transgenic gemmalings with uniform genetic backgrounds. The optimized transformation efficiencies were approximately 30 and 50 % in males and females, respectively. As with AgarTrap using sporelings, AgarTrap using intact gemmae/gemmalings will be useful in promoting studies of the molecular biology of M. polymorpha. PMID:25663453

  15. Agar disk elution method for susceptibility testing of Mycobacterium marinum and Mycobacterium fortuitum complex to sulfonamides and antibiotics.

    PubMed Central

    Stone, M S; Wallace, R J; Swenson, J M; Thornsberry, C; Christensen, L A

    1983-01-01

    An agar disk elution method using round well plates, supplemented Mueller-Hinton agar, and commercial drug disks is described for susceptibility testing of Mycobacterium marinum and the rapidly growing mycobacteria to antibiotics and sulfonamides. By this method, 14 of 14 strains of M. marinum were susceptible to rifampin, doxycycline, minocycline, and trimethoprim-sulfamethoxazole. Identical results were obtained with Middlebrook 7H10 agar and drugs prepared from standard powders. With 58 isolates of Mycobacterium fortuitum and Mycobacterium chelonei, this method had a 92% correlation with broth minimal inhibitory concentration determinations for cefoxitin and greater than 98% for doxycycline, kanamycin, amikacin, and the sulfonamides. Sixty-nine percent of isolates of M. chelonei susceptible to amikacin on supplemented Mueller-Hinton agar were resistant on 7H10 agar, and 15 of 16 M. chelonei isolates susceptible to erythromycin in broth were resistant by disk elution when an endpoint of no growth was used with either agar. The agar disk elution method offers a practical method for testing of most antibacterial agents against these mycobacterial species. Images PMID:6651277

  16. Cortical attractor network dynamics with diluted connectivity.

    PubMed

    Rolls, Edmund T; Webb, Tristan J

    2012-01-24

    The connectivity of the cerebral cortex is diluted, with the probability of excitatory connections between even nearby pyramidal cells rarely more than 0.1, and in the hippocampus 0.04. To investigate the extent to which this diluted connectivity affects the dynamics of attractor networks in the cerebral cortex, we simulated an integrate-and-fire attractor network taking decisions between competing inputs with diluted connectivity of 0.25 or 0.1, and with the same number of synaptic connections per neuron for the recurrent collateral synapses within an attractor population as for full connectivity. The results indicated that there was less spiking-related noise with the diluted connectivity in that the stability of the network when in the spontaneous state of firing increased, and the accuracy of the correct decisions increased. The decision times were a little slower with diluted than with complete connectivity. Given that the capacity of the network is set by the number of recurrent collateral synaptic connections per neuron, on which there is a biological limit, the findings indicate that the stability of cortical networks, and the accuracy of their correct decisions or memory recall operations, can be increased by utilizing diluted connectivity and correspondingly increasing the number of neurons in the network, with little impact on the speed of processing of the cortex. Thus diluted connectivity can decrease cortical spiking-related noise. In addition, we show that the Fano factor for the trial-to-trial variability of the neuronal firing decreases from the spontaneous firing state value when the attractor network makes a decision. This article is part of a Special Issue entitled "Neural Coding". PMID:21875702

  17. Comparative evaluation of chromogenic agar medium and conventional culture system for isolation and presumptive identification of uropathogens

    PubMed Central

    Akter, Laila; Haque, Rezwana; Salam, Md. Abdus

    2014-01-01

    Objective: Urine is the most frequent specimen received for culture/sensitivity by clinical laboratories. The microbiological performance of HiCrome UTI agar medium was compared with Blood agar and MacConkey agar for isolation and presumptive identification of bacteria from urine culture. Methods: A total of 443 consecutively collected midstream and/or catheter-catch urine samples from patients attending the Islami Bank Medical College Hospital, Rajshahi, Bangladesh during January to December, 2012 were cultured. Urine samples showing pus cells ≥ 5/HPF were inoculated on to Blood agar (BA), MacConkey agar (MAC) and HiCrome UTI agar (CA) media simultaneously and incubated overnight aerobically at 370C. Rate of isolation and presumptive identification of bacterial species were compared for different media. Results: Culture yielded a total of 199 bacterial isolates from 189 (42.67%) positive plates including 179 (40.40%) unimicrobial and 10 (2.26%) polymicrobial (mixed growth of pair of bacteria) growths. Both HiCrome UTI agar and Blood agar media supported 100% growths while 151 (75.88%) growths were observed on MacConkey agar. The rate of presumptive identification was found significantly higher on HiCrome UTI agar (97.49%) than MAC agar (67.34%) (P<0.001) as primary urine culture medium. Of 199 isolates, E. coli was found to be the leading uropathogen isolated from 118 (59.30%) samples with its presumptive identification rate of 95.76%, 93.22% and 5.93% on CA, MAC and BA respectively. All 10 (100%) polymicrobial growths were demonstrated distinctly on CA against only 01(10%) on each BA and MAC. Conclusion: HiCrome UTI agar was found to be more useful as primary urine culture medium in both higher rate of isolation and presumptive identification of uropathogens in comparison to conventional media. Its inherent characteristics in demonstrating polymicrobial growth and ease of rapid identification by distinct colony colour are unique. PMID:25225521

  18. Declining ecosystem health and the dilution effect.

    PubMed

    Khalil, Hussein; Ecke, Frauke; Evander, Magnus; Magnusson, Magnus; Hörnfeldt, Birger

    2016-01-01

    The "dilution effect" implies that where species vary in susceptibility to infection by a pathogen, higher diversity often leads to lower infection prevalence in hosts. For directly transmitted pathogens, non-host species may "dilute" infection directly (1) and indirectly (2). Competitors and predators may (1) alter host behavior to reduce pathogen transmission or (2) reduce host density. In a well-studied system, we tested the dilution of the zoonotic Puumala hantavirus (PUUV) in bank voles (Myodes glareolus) by two competitors and a predator. Our study was based on long-term PUUV infection data (2003-2013) in northern Sweden. The field vole (Microtus agrestis) and the common shrew (Sorex araneus) are bank vole competitors and Tengmalm's owl (Aegolius funereus) is a main predator of bank voles. Infection probability in bank voles decreased when common shrew density increased, suggesting that common shrews reduced PUUV transmission. Field voles suppressed bank vole density in meadows and clear-cuts and indirectly diluted PUUV infection. Further, Tengmalm's owl decline in 1980-2013 may have contributed to higher PUUV infection rates in bank voles in 2003-2013 compared to 1979-1986. Our study provides further evidence for dilution effect and suggests that owls may have an important role in reducing disease risk. PMID:27499001

  19. First comprehensive evaluation of the M.I.C. evaluator device compared to Etest and CLSI reference dilution methods for antimicrobial susceptibility testing of clinical strains of anaerobes and other fastidious bacterial species.

    PubMed

    Rennie, R P; Turnbull, L; Brosnikoff, C; Cloke, J

    2012-04-01

    The new M.I.C. Evaluator strip uses test methodology and the recording of results that are similar to those of Etest. For this first assessment, 102 clinical strains of anaerobic bacteria from 12 genera and 155 strains from 7 genera and 8 species of fastidious bacteria were tested by M.I.C. Evaluator, Etest, and agar dilution or broth microdilution as a reference standard. Ampicillin, amoxicillin, amoxicillin-clavulanate, cefotaxime, ciprofloxacin, erythromycin, imipenem, levofloxacin, metronidazole, penicillin, and tetracycline were tested depending on the species. Agar dilution for anaerobes was performed according to CLSI document M11-A7. For the fastidious bacteria, CLSI document M45-A2 was followed. For the anaerobes, essential and categorical agreement between M.I.C. Evaluator and Etest was >90%. Compared to agar dilution, essential agreement was low for both strip tests, and many very major errors were observed for metronidazole (13 to 14%) and penicillin (8 to 9%) with isolates from the Bacteroides fragilis group and Clostridium species. For fastidious species, essential agreements for M.I.C. Evaluator and Etest plus or minus one doubling dilution were >95%. Compared to broth microdilution, essential agreements were low (40 to 90%) plus or minus one dilution and were >90% plus or minus two dilutions, with high overall category agreement (CA). Major and minor errors were within established parameters for all strains tested. The M.I.C. Evaluator strips were equivalent to Etest for anaerobes and fastidious species. These observations require further investigation to determine which methods provide the most accurate MIC for clinical utility. The further evaluation of additional M.I.C. Evaluator agents will be performed as they become available. PMID:22238439

  20. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Dilution air and diluted exhaust flow...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related...