Isolates of Clostridium difficile from 159 hospitalized Danish patients (2005) were analysed by a new 5-plex PCR method targeting the toxin genes tcdA, tcdB, cdtA and cdtB, and 16S rDNA as an ...internal positive control. Additionally, the toxin-regulating gene tcdC was partially sequenced by a new sequencing-based method that revealed genetic changes that may render the gene product inactive. Finally tcdA was analysed using a previously published method for the detection of internal deletions. The 5-plex PCR revealed four different toxin gene profiles: 36 tcdA+, tcdB+, cdtA+ / cdtB+; one tcdA+, tcdB–, cdtA+ / cdtB+; 98 tcdA+, tcdB+, cdtA– / cdtB–; and 24 non-toxigenic tcdA–, tcdB–, cdtA– / cdtB–. Deletion studies revealed that 26 strains contained a c. 700-bp deletion in tcdA, and 39 strains contained at least one possible inactivation feature in tcdC. The prevalence of the binary toxin genes was 23%. All strains with the tcdA+, tcdB+, cdtA+ / cdtB+ profile were investigated by PCR ribotyping, and this revealed eight different ribotypes, none of which were 027. The 5-plex PCR method offers a one-step, rapid and specific screening method for C. difficile toxin genes. This toxin gene profiling, together with deletion studies in tcdA and tcdC, may allow an evaluation of the pathogenic potential of C. difficile.
The European, multicentre, quarterly point-prevalence study of community-acquired diarrhoea (EUCODI) analysed stool samples received at ten participating clinical microbiology laboratories (Austria, ...Finland, France, Germany, Greece, Ireland, Italy, Portugal, Romania, and the UK) in 2014. On four specified days, each local laboratory submitted samples from ≤20 consecutive patients to the Austrian Study Centre for further testing with the FilmArray GI Panel (BioFire Diagnostics, Salt Lake City, UT, USA). Of the 709 samples from as many patients received, 325 (45.8%) tested negative, 268 (37.8%) yielded only one organism, and 116 (16.4%) yielded multiple organisms. Positivity rates ranged from 41% (30 of 73 samples) in France to 74% (59 of 80 samples) in Romania. With the exception of Entamoeba histolytica and Vibrio cholerae, all of the 22 targeted pathogens were detected at least once. Enteropathogenic Escherichia coli, Campylobacter species, toxigenic Clostridium difficile, enteroaggregative E. coli, norovirus and enterotoxigenic E. coli were the six most commonly detected pathogens. When tested according to local protocols, seven of 128 positive samples (5.5%) yielded multiple organisms. Overall, the FilmArray GI Panel detected at least one organism in 54.2% (384/709) of the samples, as compared with 18.1% (128/709) when testing was performed with conventional techniques locally. This underlines the considerable potential of multiplex PCR to improve routine stool diagnostics in community-acquired diarrhoea. Classic culture methods directed at the isolation of specific pathogens are increasingly becoming second-line tools, being deployed when rapid molecular tests give positive results. This optimizes the yield from stool examinations and dramatically improves the timeliness of diagnosis.
Initial performance of the COSINE-100 experiment Adhikari, G.; Adhikari, P.; de Souza, E. Barbosa ...
The European physical journal. C, Particles and fields,
02/2018, Letnik:
78, Številka:
2
Journal Article
Recenzirano
Odprti dostop
COSINE is a dark matter search experiment based on an array of low background NaI(Tl) crystals located at the Yangyang underground laboratory. The assembly of COSINE-100 was completed in the summer ...of 2016 and the detector is currently collecting physics quality data aimed at reproducing the DAMA/LIBRA experiment that reported an annual modulation signal. Stable operation has been achieved and will continue for at least 2 years. Here, we describe the design of COSINE-100, including the shielding arrangement, the configuration of the NaI(Tl) crystal detection elements, the veto systems, and the associated operational systems, and we show the current performance of the experiment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
We investigate the fine-structure C
ii
line at 158
μ
m as a molecular gas tracer by analyzing the relationship between molecular gas mass (
M
mol
) and C
ii
line luminosity (
L
C
II
) in ...11,125
z
≃ 6 star-forming, main-sequence galaxies from the
simba
simulations, with line emission modeled by the Simulator of Galaxy Millimeter/Submillimeter Emission. Though most (∼50%–100%) of the gas mass in our simulations is ionized, the bulk (>50%) of the C
ii
emission comes from the molecular phase. We find a sublinear (slope 0.78 ± 0.01)
log
L
C
II
–
log
M
mol
relation, in contrast with the linear relation derived from observational samples of more massive, metal-rich galaxies at
z
≲ 6. We derive a median C
ii
-to-
M
mol
conversion factor of
α
C
II
≃ 18
M
⊙
/
L
⊙
. This is lower than the average value of ≃30
M
⊙
/
L
⊙
derived from observations, which we attribute to lower gas-phase metallicities in our simulations. Thus, a lower, luminosity-dependent conversion factor must be applied when inferring molecular gas masses from C
ii
observations of low-mass galaxies. For our simulations, C
ii
is a better tracer of the molecular gas than CO
J
= 1–0, especially at the lowest metallicities, where much of the gas is
CO-dark
. We find that
L
C
II
is more tightly correlated with
M
mol
than with star formation rate (SFR), and both the
log
L
C
II
–
log
M
mol
and
log
L
C
II
–
log
SFR
relations arise from the Kennicutt–Schmidt relation. Our findings suggest that
L
C
II
is a promising tracer of the molecular gas at the earliest cosmic epochs.
We present a background model for dark matter searches using an array of NaI(Tl) crystals in the COSINE-100 experiment that is located in the Yangyang underground laboratory. The model includes ...background contributions from both internal and external sources, including cosmogenic radionuclides and surface
210
Pb contamination. To build the model in the low energy region, with a threshold of 1 keV, we used a depth profile of
210
Pb contamination in the surface of the NaI(Tl) crystals determined in a comparison between measured and simulated spectra. We also considered the effect of the energy scale errors propagated from the statistical uncertainties and the nonlinear detector response at low energies. The 1.7 years COSINE-100 data taken between October 21, 2016 and July 18, 2018 were used for this analysis. Our Monte Carlo simulation provides a non-Gaussian peak around 50 keV originating from beta decays of bulk
210
Pb in a good agreement with the measured background. This model estimates that the activities of bulk
210
Pb and
3
H are dominating the background rate that amounts to an average level of
2.85
±
0.15
counts/day/keV/kg in the energy region of (1–6) keV, using COSINE-100 data with a total exposure of 97.7 kg
·
years.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aims
Development of a real‐time PCR method for the specific detection of
Salmonella Dublin.
Methods and Results
The method was directed towards a
Salm. Dublin‐specific sequence of the
vagC
gene on ...the
Salmonella virulence plasmid (pSDV) and towards
Salmonella genus‐specific sequence of the
invA
gene, serving as an internal amplification control. The method showed 100% inclusivity and exclusivity when tested on a strain collection containing 50 serotyped
S
. Dublin strains, 20 strains of other
Salmonella serotypes and 10 non‐
Salmonella strains. The method also showed 100% inclusivity and 99% exclusivity in a collaborative study comprising eight laboratories, where each laboratory received ten different
S
. Dublin strains and 10 other
Salmonella serotypes.
Conclusions
The method showed excellent performance both when validated in the laboratory and in the collaborative study.
Significance and Impact of the Study
Application of the present method in food control, for example at slaughterhouses, can improve the contamination control of this veterinary and clinically important
Salmonella serotype.
Two independent studies were conducted to describe symptoms and potential risk factors associated with Blastocystis infection. Isolates were subtyped by molecular analysis. In the NORMAT study (126 ...individuals randomly sampled from the general population) 24 (19%) were positive for Blastocystis. Blastocystis was associated with irritable bowel syndrome (P=0·04), contact with pigs (P<0·01) and poultry (P=0·03). In the Follow-up (FU) study (follow-up of 92 Blastocystis-positive patients), reports on bloating were associated with subtype (ST) 2 (P<0·01), and blood in stool to mixed subtype infection (P=0·06). ST1 was more common in FU individuals (32%) than in NORMAT individuals (8%), whereas single subtype infections due to ST3 or ST4 were seen in 63% of the NORMAT cases and 28% of the FU cases. Only FU individuals hosted ST7, and ST6/7 infections due to ST7 or ST9 were characterized by multiple intestinal symptoms. The data indicate subtype-dependent differences in the clinical significance of Blastocystis.
Sterility testing is a laborious and slow process to detect contaminants present in drug products. Raman spectroscopy is a promising label-free tool to detect microorganisms and thus gaining ...relevance as a future alternative culture-free method for sterility testing in the pharmaceutical industry. However, reaching detection limits similar to standard procedures while keeping a high accuracy remains challenging, due to weak bacterial Raman signals. In this work, we show a new non-invasive approach focusing on detection of different bacteria in concentrations below 100 CFU per ml within drug product containers using Raman spectroscopy and multivariate data analysis. Even though Raman spectra from drug product with and without bacteria are similar, a partial least squared discriminant analysis (PLS-DA) model shows great performance to distinguish samples with bacterial contaminants in concentrations down to 10 CFU per ml. We used spiked samples with bacterial spores for model validation achieving a detection accuracy of 99%. Our results indicate the great potential of this rapid, and cost-effective approach to be used in quality control in the pharmaceutical industry.
Fast and non-invasive approach to detect drug product (DP) samples with low numbers of bacteria within the primary packaging. The method combines Raman spectroscopy and partial least squared discriminant analysis (RS-PLS-DA).
We present a comprehensive study of the nonproportionality of NaI(Tl) scintillation detectors within the context of dark matter search experiments. Our investigation, which integrates COSINE-100 data ...with supplementary
γ
spectroscopy, measures light yields across diverse energy levels from full-energy
γ
peaks produced by the decays of various isotopes. These
γ
peaks of interest were produced by decays supported by both long and short-lived isotopes. Analyzing peaks from decays supported only by short-lived isotopes presented a unique challenge due to their limited statistics and overlapping energies, which was overcome by long-term data collection and a time-dependent analysis. A key achievement is the direct measurement of the 0.87 keV light yield, resulting from the cascade following electron capture decay of
22
Na
from internal contamination. This measurement, previously accessible only indirectly, deepens our understanding of NaI(Tl) scintillator behavior in the region of interest for dark matter searches. This study holds substantial implications for background modeling and the interpretation of dark matter signals in NaI(Tl) experiments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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