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991.
992.
The spontaneous conversion of γ-butyrolactone (GBL) to γ-hydroxybutyric acid (GHB) in seven different Swedish tap waters was investigated. The waters used in the study were selected to represent the diversity among Swedish tap waters as well as possible, which was enabled by principal component analysis (PCA) of a number of water quality parameters. GBL solutions (5, 25 and 50% v/v) were prepared in each of the tap waters and in deionized water and the formation of GHB was followed over time. The GHB quantifications were made using a CZE method, employing a carrier electrolyte consisting of 25mM benzoic acid, 54mM tris(hydroxymethyl)aminomethane (Tris) and 1.7mM tetradecyltrimethylammonium bromide (TTAB), which was developed as a part of the current study. Data evaluation showed that the formation of GHB was largely dependent on the type of tap water. For example, there was a negative correlation between the kinetics of the GHB formation and the alkalinity of the tap waters (r(2)=0.990). This could be explained by a faster decrease in pH in the waters with low buffering capacity (i.e. low alkalinity), which catalysed the hydrolysis of GBL. Equilibrium was reached after 40-250 days depending on the initial GBL concentration and the type of tap water. The level of the equilibrium appeared to be dependent on the initial GBL concentration and ranged from 26 to 37%. Gained knowledge on the levels of the GHB/GBL equilibrium and the kinetics of the formation of GHB in tap water solutions of GBL, including the influence of the tap water quality, may be useful information for casework with the GHB/GBL problem in focus. 相似文献
993.
Starting in 2008 a new designer drug, 3,4-methylenedioxypyrovalerone (MDPV) appeared among users of illegal drugs in Finland. Since then there have been several seizures of MDPV by police and customs and it has been connected to many crimes of different types. In this study the incidence and impact of the use of MDPV in drivers suspected of being under the influence of drugs (DUID) in Finland was assessed. Since autumn 2009, blood samples from drivers suspected of DUID in Finland have been analysed for the presence of MDPV. A new LC-MS/MS method for the determination of MDPV in serum was established. In order to assess the impact of MDPV on driving performance, drug and alcohol findings of positive MDPV cases were compared with data from the clinical examination carried out while the suspect was under arrest. In a period of one year there were 259 positive MDPV cases from apprehended drivers (5.7% of all confirmed DUID cases). In 80% of the cases in which MDPV was found, amphetamine was also present. Benzodiazepines were also frequently found together with MDPV, which was to be expected since in Finland, in our experience, stimulants are very often used together with benzodiazepines. In most cases it remained unclear whether the observed psycho-physical achievement deficiency was induced by MDPV because the concentrations of other drugs, especially other stimulants, were often high. However, in some subjects, MDPV, or MDPV in combination with other substances was the most probable cause of the impairment. The concentrations of MDPV varied from 0.016mg/L to over 8.000mg/L. Little is known about the pharmacology of MDPV. However, based on our findings it is clear that MDPV has a serious impact on traffic safety in Finland. 相似文献
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Through theoretical analysis and introduction of some empirical parameters, the relationship between post-braking-distance and throw distance was studied concentratedly. Here, the post-braking-distance is the distance a vehicle will travel from the impact position to when it comes to a complete stop. Two useful formulas which are meaningful in vehicle-pedestrian accident reconstruction were finally obtained. The first one can be used to calculate impact speed according to throw distance, while the other one can describe the relationship between post-braking-distance and throw distance. Their feasibility has been validated by comparing with other scholars' empirical formulas and simulation results of software Pc-Crash, respectively. The relationship between post-braking-distance and throw distance has very bright application perspective in vehicle-pedestrian accident reconstruction such as helping policemen obtain more useful evidences, validating credibility of the throw distance, judging whether the vehicle is fully braked or not, determining the impact position etc. Finally its application was demonstrated by three cases, in which the impact speed was also calculated. All results until now have shown that conclusions obtained in this article are feasible and helpful in vehicle-pedestrian accident reconstruction. 相似文献
1000.
Winkler M Kaufmann E Thoma D Thierauf A Weinmann W Skopp G Alt A 《Forensic science international》2011,210(1-3):243-246
This study aims to show that sensitive detection of ethyl glucuronide in dried blood spotted onto various surfaces after a period of 24h is feasible. At present, there is insufficient information how tightly ethyl glucuronide (EtG) binds to various materials and how easily it can be eluted. 4ml aliquots of blood samples obtained from seven volunteers after consumption of alcoholic beverages were applied to six different surfaces. After drying and a 24h-storage at 20±2°C the samples were re-dissolved in water, and EtG was subsequently analyzed by a LC-MS Paul-type ion trap. A comparison was made between dried and corresponding fluid samples. EtG was detectable in all subjects' samples following consumption of alcohol. EtG was also detectable after a storage time of four weeks at 4°C in whole blood that had been preserved with EDTA. EtG was detectable in all samples dried on different surfaces and its concentration remained relatively constant irrespective of the particular condition of the material. Detection of EtG in blood spots from the scene may indicate recent alcohol consumption in cases where collection of blood remained undone or could not be performed. 相似文献