| 1. |
- Granfors, Anna, 1978, et al.
(författare)
-
Organic iodine in Antarctic sea ice: a comparison between winter in the Weddell Sea and summer in the Amundsen Sea
- 2014
-
Ingår i: Journal of Geophysical Research - Biogeosciences. - 0148-0227 .- 2156-2202. ; 119:12, s. 2276-2291
-
Tidskriftsartikel (refereegranskat)abstract
- Recent studies have recognized sea ice as a source of reactive iodine to the Antarctic boundary layer. Volatile iodinated compounds (iodocarbons) are released from sea ice, and they have been suggested to contribute to the formation of iodine oxide (IO), which takes part in tropospheric ozone destruction in the polar spring. We measured iodocarbons (CH3I, CH2ClI, CH2BrI and CH2I2) in sea ice, snow, brine and air during two expeditions to Antarctica, OSO 10/11 to the Amundsen Sea during austral summer, and ANT XXIX/6 to the Weddell Sea in austral winter. These are the first reported measurements of iodocarbons from the Antarctic winter. Iodocarbons were enriched in sea ice in relation to seawater in both summer and winter. During summer the positive relationship to Chl a biomass indicated a biological origin. We suggest that CH3I is formed biotically in sea ice during both summer and winter. For CH2ClI, CH2BrI and CH2I2 an additional abiotic source at the snow-ice interface in winter is suggested . Elevated air concentrations of CH3I and CH2ClI during winter indicate that they are enriched in lower troposphere and may take part in formation of IO at polar sunrise.
|
|
| 2. |
- Olsson, A. O., et al.
(författare)
-
Variability of the IS revealed ionization enhancement by bile acid in mouse plasma
- 2013
-
Ingår i: Bioanalysis. - : Future Science Ltd. - 1757-6180 .- 1757-6199. ; 5:19, s. 2371-2378
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Elevated IS response was observed in 22 out of 157 mouse plasma samples in a 3-month toxicity study. This initiated a root cause investigation. Results: Mass spectra revealed that taurocholic acid (TCA) was present in the samples, partially eluted overlapping the analyte peak. An enhanced IS response (>twofold) was reproduced by injecting TCA together with the IS. Tests with five other drug compounds showed compound dependent matrix effects on ESI; enhancement as well as suppression. The matrix effects did not affect the integrity of study results, most likely due to the use of a C-13-labeled IS. Conclusion: The variability of TCA levels in plasma as well as the observed instability of the chromatographic retention complicates the evaluation of TCA-induced matrix effects during method development. Thus, monitoring the IS response in incurred samples is a useful tool to evaluate the performance of a validated method.
|
|
| 3. |
- Pettersson, Stefan, 1972, et al.
(författare)
-
A Hydrogel Drink With High Fructose Content Generates Higher Exogenous Carbohydrate Oxidation and Lower Dental Biofilm pH Compared to Two Other, Commercially Available, Carbohydrate Sports Drinks
- 2020
-
Ingår i: Frontiers in Nutrition. - : Frontiers Media SA. - 2296-861X. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate the substrate oxidation of three commercially available, 14%-carbohydrate sports drinks with different compositions, osmolality, and pH for their impact on dental exposure to low pH. In a cross-over, randomized double-blinded design, 12 endurance athletes (age 31. 2 +/- 7.7 years, (V) over dotO(2max) 65.6 +/- 5.0 mL.kg(-1)) completed 180 min of cycling at 55% W-max. During the first 100 min of cycling, athletes consumed amylopectin starch (AP), maltodextrin+sucrose (MD+SUC), or maltodextrin+fructose hydrogel (MD+FRU) drinks providing 95 g carbohydrate.h(-1), followed by water intake only at 120 and 160 min. Fuel use was determined using indirect calorimetry and stable-isotope techniques. Additionally, dental biofilm pH was measured using the microtouch method in a subsample of participants (n= 6) during resting conditions before, and at different time intervals up to 45 min following a single bolus of drink. Exogenous carbohydrate oxidation (CHOEXO) during the 2nd hour of exercise was significantly (P< 0.05) different between all three drinks: MD+FRU (1.17 +/- 0.17 g.min(-1)), MD+SUC (1.01 +/- 0.13 g.min(-1)), and AP (0.84 +/- 0.11 g.min(-1)). At the end of exercise, CHO(EXO)and blood glucose concentrations (3.54 +/- 0.50, 4.07 +/- 0.67, and 4.28 +/- 0.47 mmol.L-1, respectively) were significantly lower post MD+FRU consumption than post MD+SUC and AP consumption (P< 0.05). Biofilm acidogenicity at rest demonstrated a less pronounced pH fall for MD+FRU compared to the acidulant-containing MD+SUC and AP (P< 0.05). In conclusion, while total intake of MD+FRU showed signs of completed uptake before end of monitoring, this was less so for MD+SUC, and not at all the case for AP. Thus, this study showed that despite carbohydrates being encapsulated in a hydrogel, a higher CHO(EXO)was observed following MD+FRU drink ingestion compared to AP and MD+SUC consumption upon exposure to the acidic environment of the stomach. This finding may be related to the higher fructose content of the MD+FRU drink compared with the MD+SUC and AP drinks. Furthermore, a carbohydrate solution without added acidulants, which are commonly included in commercial sport drinks, may have less deleterious effects on oral health.
|
|
