999 resultados para rapid solidification


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The development of a quick PCR-based method to distinguish European cryptic Myotis spp., Myotis mystacinus, Myotis brandtii and Myotis alcathoe is described. Primers were designed around species-specific single nucleotide polymorphisms (SNP's) in the ND1 mitochondrial gene, and a pair of control primers was designed in the 12S mitochondrial gene. A multiplex of seven primer combinations produces clear species-specific bands using gel electrophoresis. Robustness of the method was tested on 33 M. mystacinus, 16 M. brandtii and 15 M. alcathoe samples from across the European range of these species. The method worked well on faecal samples collected from maternity roosts of M. mystacinus. The test is intended to aid collection of data on these species through a rapid and easy identification method with the ability to use DNA obtained from a range of sources including faecal matter.

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A rapid design methodology for orthonormal wavelet transform cores has been developed. This methodology is based on a generic, scaleable architecture utilising time-interleaved coefficients for the wavelet transform filters. The architecture has been captured in VHDL and parameterised in terms of wavelet family, wavelet type, data word length and coefficient word length. The control circuit is embedded within the cores and allows them to be cascaded without any interface glue logic for any desired level of decomposition. Case studies for stand alone and cascaded silicon cores for single and multi-stage wavelet analysis respectively are reported. The design time to produce silicon layout of a wavelet based system has been reduced to typically less than a day. The cores are comparable in area and performance to handcrafted designs. The designs are portable across a range of foundries and are also applicable to FPGA and PLD implementations.

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The impact of rapid climate change on contemporary human populations is of global concern. To contextualize our understanding of human responses to rapid climate change it is necessary to examine the archeological record during past climate transitions. One episode of abrupt climate change has been correlated with societal collapse at the end of the northwestern European Bronze Age. We apply new methods to interrogate archeological and paleoclimate data for this transition in Ireland at a higher level of precision than has previously been possible. We analyze archeological 14C dates to demonstrate dramatic population collapse and present high-precision proxy climate data, analyzed through Bayesian methods, to provide evidence for a rapid climatic transition at ca. 750 calibrated years B.C. Our results demonstrate that this climatic downturn did not initiate population collapse and highlight the nondeterministic nature of human responses to past climate change.

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L-Lactate was produced from xylose using electrodialysis culture (ED-C)-associated product separation. In a medium containing 50 g xylose/l, the ED-C was completed in only 32 h (i.e. less than half the time taken by the control culture, without electrodialysis). At 80 g xylose/l, the control culture was unable to consume more than 50 g xylose/1, whereas the ED-C showed increased xylose consumption and was completed by 45 h. The maximum rate of lactate production in the ED-C was higher than that in the control culture. ED-C was also carried out (at 80 g initial xylose/ l) with a supply of fresh xylose-free medium. This ED-C was completed within 30 h, which represents a reduction in fermentation time of 15 h when compared to ED-C without addition of xylose-free medium. Thus, rapid production of L-lactate was achieved by using ED-C which supplied fresh xylose-free medium.

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A procedure was developed to extract polyols and trehalose (protectants against stress) from fungal conidia. Conidia were sonicated (120 s) and immersed in a boiling water bath (5.5 min) to optimize extraction of polyols and trehalose, respectively. A rapid method was developed to separate and detect low-molecular-weight polyols and trehalose using high-performance liquid chromatography (HPLC). An ion exchange column designed for standard carbohydrate analysis was used in preference to one designed for sugar alcohol separation. This resulted in rapid elution (less than 5 min), without sacrificing peak resolution. The use of a pulsed electrochemical detector (gold electrode) resulted in limits of reliable quantification as low as 1.6 μg ml-1 for polyols and 2.8 μg ml-1 for trehalose. This is very sensitive and rapid method by which these protectants can be analysed. It avoids polyol derivatization that characterizes analysis by gas chromatography and the long run times (up to 45 min) that typify HPLC analysis using sugar alcohol columns.

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Pseudomonas aeruginosa genotyping relies mainly upon DNA fingerprinting methods, which can be subjective, expensive and time-consuming. The detection of at least three different clonal P. aeruginosa strains in patients attending two cystic fibrosis (CF) centres in a single Australian city prompted the design of a non-gel-based PCR method to enable clinical microbiology laboratories to readily identify these clonal strains. We designed a detection method utilizing heat-denatured P. aeruginosa isolates and a ten-single-nucleotide polymorphism (SNP) profile. Strain differences were detected by SYBR Green-based real-time PCR and high-resolution melting curve analysis (HRM10SNP assay). Overall, 106 P. aeruginosa sputum isolates collected from 74 patients with CF, as well as five reference strains, were analysed with the HRM10SNP assay, and the results were compared with those obtained by pulsed-field gel electrophoresis (PFGE). The HRM10SNP assay accurately identified all 45 isolates as members of one of the three major clonal strains characterized by PFGE in two Brisbane CF centres (Australian epidemic strain-1, Australian epidemic strain-2 and P42) from 61 other P. aeruginosa strains from Australian CF patients and two representative overseas epidemic strain isolates. The HRM10SNP method is simple, is relatively inexpensive and can be completed in <3 h. In our setting, it could be made easily available for clinical microbiology laboratories to screen for local P. aeruginosa strains and to guide infection control policies. Further studies are needed to determine whether the HRM10SNP assay can also be modified to detect additional clonal strains that are prevalent in other CF centres.

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Essay review of:
Immigration and Schooling in the Republic of Ireland: Making a Difference?, by Dympna Devine . Manchester, UK: Manchester University Press, 2012. 186pp. $24.95 paper. ISBN: 9780719081026.
Immigration and Social Cohesion in the Republic of Ireland, by Bryan Fanning . Manchester, UK: Manchester University Press, 2011. 202pp. $24.95 paper. ISBN: 9780719084799.
Understanding Immigration in Ireland: State, Capital and Labour in a Global Age, by Steven Loyal . Manchester, UK: Manchester University Press, 2011. 283pp. $24.95 paper. ISBN: 9780719078316.

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The opportunistic human pathogen Propionibacterium acnes is comprised of a number of distinct phylogroups, designated types IA1, IA2, IB, IC, II and III, that vary in their production of putative virulence factors, inflammatory potential, as well as biochemical, aggregative and morphological characteristics. Although Multilocus Sequence Typing (MLST) currently represents the gold standard for unambiguous phylogroup classification, and individual strain identification, it is a labour and time-consuming technique. As a consequence, we have developed a multiplex touchdown PCR assay that will, in a single reaction, confirm species identity and phylogeny of an isolate based on its pattern of reaction with six primer sets that target the 16S rRNA (all isolates), ATPase (type IA1, IA2, IC), sodA (type IA2, IB), atpD (type II) and recA (type III) housekeeping genes, as well as a Fic family toxin gene (type IC). When applied to 312 P. acnes isolates previously characterised by MLST, and representing type IA1 (n=145), IA2 (n=20), IB (n=65), IC (n=7), II (n=45) and III (n=30), the multiplex displayed 100% sensitivity and 100% specificity for the detection of isolates within each targeted phylogroup. No cross-reactivity with isolates from other bacterial species was observed. The multiplex assay will provide researchers with a rapid, high-throughput and technically undemanding typing method for epidemiological and phylogenetic investigations. It will facilitate studies investigating the association of lineages with various infections and clinical conditions, as well as a pre-screening tool to maximise the number of genetically diverse isolates selected for downstream, higher resolution sequence-based analyses.

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Antimicrobial residues found to be present in milk can have both health and economic impacts. For these reasons, the widespread routine testing of milk is required. Due to delays with sample handling and test scheduling, laboratory-based tests are not always suited for making decisions about raw material intake and product release, especially when samples require shipping to a central testing facility. Therefore, rapid on-site screening tests that can produce results within a matter of minutes are required to facilitate rapid intake and product release processes. Such tests must be simple for use by non-technical staff. There is increasing momentum towards the development and implementation of multiplexing tests that can detect a range of important antimicrobial residues simultaneously. A simple in situ multiplexed planar waveguide device that can simultaneously detect chloramphenicol, streptomycin and desfuroylceftiofur in raw dairy milk, without sample preparation, has been developed. Samples are simply mixed with antibody prior to an aliquot being passed through the detection cartridge for 5 min before reading on a field-deployable portable instrument. Multiplexed calibration curves were produced in both buffer and raw milk. Buffer curves, for chloramphenicol, streptomycin and desfuroylceftiofur, showed linear ranges (inhibitory concentration (IC)20–IC80) of 0.1–0.9, 3–129 and 12–26 ng/ml, whilst linear range in milk was 0.13–0.74, 11–376 and 2–12 ng/ml, respectively, thus meeting European legislated concentration requirements for both chloramphenicol and streptomycin, in milk, without the need for any sample preparation. Desfuroylceftiofur-contaminated samples require only simple sample dilution to bring positive samples within the range of quantification. Assay repeatability and reproducibility were lower than 12 coefficient of variation (%CV), whilst blank raw milk samples (n = 9) showed repeatability ranging between 4.2 and 8.1 %CV when measured on all three calibration curves.


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Leptospirosis is a globally important zoonotic infection caused by spirochaetes of the genus Leptospira. It is transmitted to humans by direct contact with infected animals or indirectly via contaminated water. It is mainly a problem of the resource-poor developing countries of the tropical and sub-tropical regions of the world but outbreaks due to an increase in travel and recreational activities have been reported in developed and more industrialized areas of the world. Current methods of diagnosis are costly, time-consuming and require the use of specialized laboratory equipment and personnel. The purpose of this paper is to report the validation of the 'Leptorapide®' test (Linnodee Ltd, Northern Ireland) for the diagnosis of human leptospirosis. It is a simple one-step latex agglutination assay performed using equal volumes of serum sample and antigen-bound latex beads. Evidence of leptospiral antibodies is determined within minutes. Agglutination is scored on a scale of 1-5 and the results interpreted using a score card provided with the kit. Validation has been performed with a large sample size obtained from individuals originating from various parts of the world including Brazil and India. The test has shown sensitivity and specificity values of 97·1% and 94·0%, respectively, relative to the microscopic agglutination test. The results demonstrate that Leptorapide offers a cost-effective and accurate alternative to the more historical methods of antibody detection.