We have developed a rapid and robust technological solution including a membrane filtration and dissolution method followed by a molecular enrichment and a real-time PCR assay, for detecting the ...presence of
Enterococcus sp. or
Enterococcus faecalis/
faecium per 100 mL of water in less than 5 h and we compared it to Method 1600 on mEI agar in terms of specificity, sensitivity, and limit of detection. The mEI and the
Enterococcus sp.-specific assay detected respectively 73 (64.0%) and 114 (100%) of the 114 enterococcal strains tested. None of the 150 non-enterococcal strains tested was detected by both methods with the exception of
Tetragenococcus solitarius for the
Enterococcus sp. assay. The multiplexed
E. faecalis/
faecium assay efficiently amplified DNA from 47 of 47 (100%)
E. faecalis and 27 of 27 (100%)
E. faecium strains tested respectively, whereas none of the 191 non-
E. faecalis/
faecium strains tested was detected. By simultaneously detecting the predominant fecal enterococcal species, the
E. faecalis/
faecium-specific assay allows a better distinction between enterococcal strains of fecal origin and those provided by the environment than Method 1600. Our procedure allows the detection of 4.5 enterococcal colony forming units (CFU) per 100 mL in less than 5 h, whereas the mEI method detected 2.3 CFU/100 mL in 24 h (95% confidence). Thus, our innovative and highly effective method provides a rapid and easy approach to concentrate very low numbers of enterococcal cells present in a 100 mL water sample and allows a better distinction between fecal and environmental enterococcal cells than Method 1600.
► We have developed a rapid and robust technological solution for detecting the presence of
Enterococcus sp. or
Enterococcus faecalis/
faecium in water. ► Our new procedure allows the detection of 4.5 enterococcal colony forming units (CFU) per 100 mL in less than 5 h. ► The
Enterococcus sp.-specific assay detected 100% of the 114 enterococcal strains tested. ► The multiplexed
E. faecalis/
faecium assay efficiently amplified DNA from 100% of
E. faecalis and
E. faecium strains tested. ► The
E. faecalis/
faecium-specific assay allows a better distinction between enterococcal strains of fecal origin and those provided by the environment than Method 1600.
Characterizing the Performance of Pipe Bombs Oxley, Jimmie C.; Smith, James L.; Bernier, Evan T. ...
Journal of forensic sciences,
January 2018, 2018-Jan, 2018-01-00, 20180101, Volume:
63, Issue:
1
Journal Article
Peer reviewed
Pipe bombs of steel or PVC fragment in reproducible patterns when similarly configured. The power of the explosion correlates with number, mass, and size of the fragments recovered, where a large ...number of small, low‐mass fragments indicate a high‐power event and vice versa. In discussing performance, describing pipe fragmentation pattern by fragment weight distribution mapping (FWDM) or fragment surface area distribution mapping (FSADM) was useful. When fillers detonated, detonation velocities of ~4.4 mm/μs were measured. In such cases, side walls of the pipe were thrown first; the average fragment velocity was ~1000 km/s. In deflagrations, the end cap was first thrown; fragment velocities were only ~240 km/s. Blast overpressures varied; at 10 feet, 2 × 12 inch steel pipes containing ~550 g of detonable mixture produced overpressures of 5–6 psi; similar nondetonating pipes produced less than 2 psi. Maximum fragment throw distances were 250–300 m, with an average of ~100 m.
Colilert
® (Colilert), Readycult
® Coliforms 100 (Readycult), Chromocult
® Coliform agar ES (Chromocult), and MI agar (MI) are β-galactosidase and β-glucuronidase-based commercial culture methods ...used to assess water quality. Their analytical performance, in terms of their respective ability to detect different strains of
Escherichia coli and total coliforms, had never been systematically compared with pure cultures. Here, their ability to detect β-glucuronidase production from
E. coli isolates was evaluated by using 74
E. coli strains of different geographic origins and serotypes encountered in fecal and environmental settings. Their ability to detect β-galactosidase production was studied by testing the 74
E. coli strains as well as 33 reference and environmental non-
E. coli total coliform strains. Chromocult, MI, Readycult, and Colilert detected β-glucuronidase production from respectively 79.9, 79.9, 81.1, and 51.4% of the 74
E. coli strains tested. These 4 methods detected β-galactosidase production from respectively 85.1, 73.8, 84.1, and 84.1% of the total coliform strains tested. The results of the present study suggest that Colilert is the weakest method tested to detect β-glucuronidase production and MI the weakest to detect β-galactosidase production. Furthermore, the high level of false-negative results for
E. coli recognition obtained by all four methods suggests that they may not be appropriate for identification of presumptive
E. coli strains.
The enzyme-based test methods Enterolert, Chromocult Enterococci agar, and mEI agar, used to assess water quality through the detection Enterococcus spp., have been compared in terms of their ...analytical specificity and their ability to detect various enterococcal strains. To achieve this goal, we have tested 110 different non-enterococcal bacterial strains and 101 strains of Enterococcus spp. isolated from diverse origins. The results obtained showed that 69 (68.3%), 84 (83.2%), and 89 (88.1%) of the 101 enterococcal strains tested respectively yielded a positive signal with Enterolert, mEI, and Chromocult Enterococci. Regarding the specificity, none of the non-Enterococcus spp. strains tested were detectable by any of the three culture methods, except for Granulicatella adiacens which turned out positive on Chromocult Enterococci. The results of this study showed that, based on our collection of strains, the Enterolert test method detected less enterococcal strains than the two other methods.
A new method for the representation and comparison of irregular two-dimensional shapes is presented. This method uses a polar transformation of the contour points about the geometric centre of the ...object. The distinctive vertices of the shape are extracted and used as comparative parameters to minimize the difference of contour distance from the centre. Experiments are performed, more than 39
000 comparisons of database shapes, provided by Sebastian et al. (ICCV (2001) 755), are made and the results are compared to those obtained therein. In addition, 450 comparisons of leaf shape are made and leaves of very similar shape are accurately distinguished. The method is shown to be invariant to translation, rotation and scaling and highly accurate in shape distinction. The method shows more tolerance to scale variation than that of Sebastian et al. (ICCV (2001) 755) and is less computationally intense.
Measurements of direct photon production in p+Pb and p+C collisions at $\sqrt{s_\mathrm{NN}} = 17.4\mathrm{GeV}$ are presented. Upper limits on the direct photon yield as a function of $p_\mathrm{T}$ ...are derived and compared to the results for Pb+Pb collisions at $\sqrt{s_\mathrm{NN}} = 17.3$ GeV. The production of the $\eta$ meson, which is an important input to the direct photon signal extraction, has been determined in the $\eta \rightarrow 2\gamma$ channel for p+C collisions at $\sqrt{s_\mathrm{NN}} = 17.4\mathrm{GeV}$.
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