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A major problem within forest industry is unwanted browsing on seedlings from mammalian herbivores. The aim of this study was to evaluate the effects of birch bark extracts as repellents towards fallow deer. Birch bark was extracted in a conventional way with ethanol as solvent at ambient temperature and with a new method, liquid CO 2 extraction. An analysis of the ethanol-extracted birch bark showed that it contained large amounts of terpenoids, of which the most abundant was betulin. In seven different treatment trials, we used 15 individually handled fallow deer. To investigate the binary taste preferences, birch bark extract was added to food and presented in two bowls in typical two-choice tests. We found that the amount of a food type consumed during a trial and the number of shifts between food bowls were dependent on the amount of the birch extract the food contained. Concentrations of above 1 % by dry weight of birch extract acted as a repellent. In addition, such concentrations produced shorter feeding bouts by a greater willingness to change bowls. Therefore, our conclusion is that birch bark extract acts as a repellent towards fallow deer and is therefore likely to act as a repellent against other deer species. In addition, we show that birch bark extract produced by the new and more environmentally sustainable method employing liquid CO 2 mixed with ethanol has the same repellent effect as the traditional ethanol extraction. [ABSTRACT FROM AUTHOR]

Abstract: Experiments with birch bark samples have been carried to enable a distinction between extraction and degradation effects during pressurised hot water extraction. Two samples, E80 and E180, contained birch bark extracts obtained after extraction at 80 and 180°C for up to 45min, respectively. Two other samples, P80 and P180, were only extracted for 5min at the two temperatures and were thereafter filtered and hydrothermally treated at 80 and 180°C, respectively. During the latter treatment, samples were collected at different times to assess the stability of the extracted compounds. An offline DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, as well as a high performance liquid chromatographic separation coupled to an electrochemical detector, were used to determine the antioxidant capacity of the processed samples. The results obtained with the different techniques were compared to assess the yield of the extraction and degradation processes. In addition, an online hyphenated system comprising high performance liquid chromatography coupled to diode-array; electrochemical; and tandem mass spectrometric detection (HPLC-DAD-ECD-MS/MS) was used to study the compositions of the extracts in more detail. The results for the samples processed at 80°C showed that the extraction reached a steady-state already after 5min, and that the extracted compounds were stable throughout the entire extraction process. Processing at 180°C, on the other hand, gave rise to partly degraded extracts with a multitude of peaks in both the diode array and electrochemical detectors, and a higher antioxidant capacity compared to for the extracts obtained at 80°C. It is concluded that HPLC-DAD-ECD is a more appropriate technique for the determination of antioxidants than the DPPH assay. The mass spectrometric results indicate that one of the extracted antioxidants, catechin, was isomerised to its diastereoisomers; (+)-catechin, (−)-catechin, (+)-epicatechin, and (−)-epicatechin. [Copyright &y& Elsevier]

Purpose. To describe the successful use of dexmedetomidine as the primary procedural sedative for a percutaneous tracheotomy procedure and to systematically present the supporting literature. Materials and Methods. A Case report of our experience and systematic literature search. PubMed, Embase, and Google Scholar were searched without restriction using the key words dexmedetomidine, percutaneous tracheotomy, and tracheotomy procedure. All relevant published references were retrieved irrespective of their methodological quality. Results. In total, only 3 relevant references were found. These include one small placebo controlled randomized trial and 2 case reports. The randomized, placebo controlled trial enrolled patients already sedated on midazolam and included 64 total patients. The 2 other case reports both described the use of dexmedetomidine as the primary procedural sedative. All of the cases reported the successful completion of the percutaneous tracheotomy without any major complication, but none reported the subjective patient experience. Conclusion. Based on the available published literature and our experience, we suggest that dexmedetomidine be considered for use as the primary procedural sedative for percutaneous tracheotomy procedure. Dexmedetomidine's ability to provide adequate sedation and amnesia, without blunting the respiratory drive and protective reflexes of the patient, may make it an optimal agent in specific cases. [ABSTRACT FROM AUTHOR]

It is demonstrated that electrochemistay (EC) coupled to liquid chromatography (LC) and electrospray ionization tandem mass spectrometry (LC/EC/ESI-MS/MS) can be used to rapidly obtain infonnation about the antioxidant activity (i.e., oxidation potential) and capacity (i.e., amount) of polyphenolic compounds, including catechin, kaempferol, resveralrol, quercetin, and quercetin glucosides. The described on-line LC/EC/ESI-MS/MS method facilitates the detection and characterization of individual antioxidants based on a combination of the obtained m/z values for the antioxidants and their oxidation products, the potential dependences for the ion intensities, and correlations between the retention times in the LU, EC, and MS chromatograms. As these results provide patterns that can be used in rapid screening for antioxidanis in complex samples, the method should be a valuable complement to chemical assays commonly used to determine the total antioxidant capacity of samples. It is shown that the antioxidant capacity for a mixture of polyphenolic compounds depends on the redox potential employed in the evaluation, and this should consequently be taken into account when comparing results from different total antioxidant capacity assays. It is also demonstrated that the inherent antioxidant capacities of phenolic compounds increase with an increasing number of hydroxyl groups and that the potential needed to oxidize the remaining hydruxyl groups increases successively upon oxidation of the compound. Unlike chemical assays, which generally do not provide any information about the identities of the compounds on the molecular level, the present screening method can be used to identify individual anti-oxidants, rank compounds with respect to their ease of oxidation, and to study the antioxidant capacity at any redox potential of interest [ABSTRACT FROM AUTHOR]

Pressurized hot (subcritical) water and ethanol were used to extract betulin and antioxidants from birch bark. Betulin was found to be the major compound (around 26% (w/w)), which was able to be extracted with ethanol (120 °C, 50 bar, 15 minutes) but not with water at any of the temperatures tested (40–180 °C, 50 bar). The obtained extraction result for betulin is supported by theoretical solvation parameter calculations. Furthermore, high antioxidant activity of the extract was obtained using both ethanol and water as solvent. The antioxidant activity, as determined by a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, was found to be highest for the water extract of finely ground bark and it markedly increased with elevated extraction temperatures (90–180 °C). To elucidate if this was due to increased extraction efficiency or chemical reactions, a set of experiments was performed in which the samples were pre-treated with water at different temperatures before extraction. Results from liquid chromatography showed some differences in molecular composition between samples pre-treated at ambient and 180 °C, respectively. However, more detailed studies have to be performed to distinguish between hot-water extraction and reaction kinetics. [ABSTRACT FROM AUTHOR]

A magnetic particle-based immuno-supported liquid membrane assay (m-ISLMA) based on chemiluminescence detection of a horseradish peroxidase-labeled hapten tracer that allows sample cleanup, analyte enrichment, and detection in a single analysis unit has been developed. Antibodies were immobilized on magnetic beads, and their position in the acceptor was controlled by two alternating opposing electromagnetic fields generated by a voltage applied to either of two electromagnets placed below and above the acceptor channel of the supported liquid membrane unit. The influence of antibody bead dilution in the acceptor was investigated and found to follow the ISLM theory, that is improved enrichment and sensitivity with increasing antibody concentration. Two different extraction procedures were investigated: procedure 1 (m-ISLMA-P1), which keeps the antibody beads trapped at the bottom of the acceptor during the entire analysis process; and procedure 2 (m-ISLMA-P2), which keeps the antibody beads dispersed and in motion in the acceptor phase during the extraction process. m-ISLMA- P2 resulted in 2000 times improved enrichment of simazine and a more than 3 orders of magnitude better limit of detection (LOD10%) (1.29 × 10-5 μg L-1) than for m-ISLMA-P1 (2.00 × 10-2 μg L-1) and corresponding microtiter plate magnetic particle-based ELISA (m-ELISA, LOD10% 1.30 × 10-1 μg L-1). m-ISLMA-P2 and m-ELISA were further applied for the extraction and analysis of simazine-spiked surface water and fruit juice, finding no evidence for matrix influence for the former method; however, indications that trace amounts (nanograms per liter) of simazine or specific cross-reactants were present in both samples. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a trans-disciplinary assessment of new and innovative biorefinery concepts producing high-value chemical compounds from residues from agriculture, food and forest industries. There is a significant potential of biomass residues in Sweden suitable for the extraction of various compounds, including upgrading by biocatalytic processes, in addition to current energy generation. Two examples presented are quercetin extracted from onion waste by pressurised hot water in conjunction with enzymatic hydrolysis, and betulin from birch bark extracted by liquid CO2 containing ethanol. Inherent in these two extraction processes and production routes is the ability to show good environmental performance from a life cycle perspective. Extraction of high-value compounds also provides possibilities for innovation in the current agricultural, food and forest industry potentially leading to socio-economical benefits. [Copyright &y& Elsevier]