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Moestedt J.,Public-i | Moestedt J.,Swedish University of Agricultural Sciences | Malmborg J.,Public-i | Malmborg J.,Swedish National Laboratory of Forensic Science | Nordell E.,Public-i
Energies | Year: 2015

To optimize commercial-scale biogas production, it is important to evaluate the performance of each microbial step in the anaerobic process. Hydrolysis and methanogenesis are usually the rate-limiting steps during digestion of organic waste and by-products. By measuring biogas production and methane concentrations on-line in a semi-continuously fed reactor, gas kinetics can be evaluated. In this study, the rate constants of the fermentative hydrolysis step (kc) and the methanogenesis step (km) were determined and evaluated in a continuously stirred tank laboratory-scale reactor treating food and slaughterhouse waste and glycerin. A process additive containing Fe2+, Co2+ and Ni2+ was supplied until day 89, after which Ni2+ was omitted. The omission resulted in a rapid decline in the methanogenesis rate constant (km) to 70% of the level observed when Ni2+ was present, while kc remained unaffected. This suggests that Ni2+ mainly affects the methanogenic rather than the hydrolytic microorganisms in the system. However, no effect was initially observed when using conventional process monitoring parameters such as biogas yield and volatile fatty acid concentration. Hence, formation rate constants can reveal additional information on process performance and km can be used as a complement to conventional process monitoring tools for semi-continuously fed anaerobic digesters. © 2015 by the authors. Source


Welch L.A.,University of Strathclyde | Gill P.,Norwegian Institute of Public Health | Gill P.,University of Oslo | Phillips C.,University of Santiago de Compostela | And 5 more authors.
Forensic Science International: Genetics | Year: 2012

To support and to underpin the European initiative to increase the European set of standard markers (ESS), by the addition of five new loci, a collaborative project was organised by the European Network of Forensic Science Institutes (ENFSI) DNA working group in order to assess the new multiplex kits available. We have prepared allele frequency databases from 26 EU populations. Concordance studies were carried out to verify that genotyping results were consistent between kits. Population genetics studies were conducted and it was estimated that FST < 0.001. The results showed that the kits were comparable to each other in terms of performance and major discrepancy issues were highlighted. We provide details of allele frequencies for each of the populations analysed per laboratory. © 2012 Published by Elsevier Ireland Ltd. Source


Hedman J.,Swedish National Laboratory of Forensic Science | Hedman J.,Lund University | Albinsson L.,Swedish National Laboratory of Forensic Science | Noren L.,Swedish National Laboratory of Forensic Science | And 2 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2011

In 2009-2010, several forensic DNA profiling kits customised for Europe and the Prüm Treaty were commercially released. The manufacturers have made efforts to increase the PCR inhibitor tolerance compared to previous kits, as shown by their increased resistance to known molecular inhibitors such as humic acid and haematin. We have evaluated three new 15 STR-marker profiling kits (Amp. FlSTR NGM, PowerPlex ESI16 and PowerPlex ESX16) on various PCR-inhibitory crime scene samples. All three kits produced usable DNA profiles from most samples. However, the kits were affected by inhibitory compounds from some of the samples, resulting in partial DNA profiles. © 2011 Elsevier Ireland Ltd. Source


Albinsson L.,Swedish National Laboratory of Forensic Science | Hedman J.,Swedish National Laboratory of Forensic Science | Hedman J.,Lund University | Ansell R.,Swedish National Laboratory of Forensic Science | Ansell R.,Linkoping University
Forensic Science International: Genetics Supplement Series | Year: 2011

In the autumn of 2010 SKL performed in-house validation of PowerPlex ESX 16 System (Promega). As the validation showed that very low amounts of DNA (∼10. pg) may provide correct allele callings (peaks above 50. rfu), we investigated the linear range, i.e., the interval of DNA amounts where a profile is well balanced and does not contain drop-outs and/or drop-ins. The linear range as indicated by our results is approximately from 0.5. ng (manufacturer's recommendation) to 2.0. ng of DNA. As minute DNA amounts may be detected using the kit, extra care needs to be taken not to report a contaminant allele as a part of the correct profile. A way to verify the correctness of a single donor profile in routine analysis, without using duplicate analysis, is to use conservative peak height thresholds. We determine STR marker specific peak height thresholds for each new lot of DNA profiling kits, based on the results from three different tests: heterozygote balance, signal intensity and repeatability, and PCR inhibitor tolerance. The tests also serve to verify the quality of the kit lot. Generally, the peak height thresholds vary between 200 and 250. rfu for heterozygote alleles, with doubled values used for homozygotes. © 2011 Elsevier Ireland Ltd. Source


Olsen E.-L.,Swedish National Laboratory of Forensic Science | Edenberger E.,Swedish National Laboratory of Forensic Science | Mattsson M.,Swedish National Laboratory of Forensic Science | Ansell R.,Swedish National Laboratory of Forensic Science | Ansell R.,Linkoping University
Forensic Science International: Genetics Supplement Series | Year: 2011

On clothing, in particular underwear, several body fluids can be present due to natural causes. Knowledge on limitations of tests used for locating stains or indication to their origin is therefore important. The Phadebas® Forensic Press test was used for amylase detection in single source samples on textile, and underwear with naturally deposited stains. Results show that other body fluids than saliva can react within the time frame stipulated on false positives, implying caution interpreting positive results. © 2011 Elsevier Ireland Ltd. Source

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