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| 2. |
- Adams, Kelly L., et al.
(författare)
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Steady-State Electrochemical Determination of Lipidic Nanotube Diameter Utilizing an Artificial Cell Model
- 2010
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 82:3, s. 1020-1026
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Tidskriftsartikel (refereegranskat)abstract
- By exploiting the capabilities of steady-state electrochemical measurements, we have measured the inner diameter of a lipid nanotube using Fick’s first law of diffusion in conjunction with an imposed linear concentration gradient of electroactive molecules over the length of the nanotube. Fick’s law has been used in this way to provide a direct relationship between the nanotube diameter and the measurable experimental parameters Δi (change in current) and nanotube length. Catechol was used to determine the Δi attributed to its flux out of the nanotube. Comparing the nanotube diameter as a function of nanotube length revealed that membrane elastic energy was playing an important role in determining the size of the nanotube and was different when the tube was connected to either end of two vesicles or to a vesicle on one end and a pipet tip on the other. We assume that repulsive interaction between neck regions can be used to explain the trends observed. This theoretical approach based on elastic energy considerations provides a qualitative description consistent with experimental data.
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| 3. |
- Hakonen, Aron, 1970, et al.
(författare)
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A potential tool for high-resolution monitoring of ocean acidification.
- 2013
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 786, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Current anthropogenic carbon dioxide emissions generate besides global warming unprecedented acid-ification rates of the oceans. Recent evidence indicates the possibility that ocean acidification and lowoceanic pH may be a major reason for several mass extinctions in the past. However, a major bottleneck forresearch on ocean acidification is long-term monitoring and the collection of consistent high-resolutionpH measurements. This study presents a low-power (<1 W) small sample volume (25l) semiconductor based fluorescence method for real-time ship-board pH measurements at high temporal and spatialresolution (approximately 15 s and 100 m between samples). A 405 nm light emitting diode and the blueand green channels from a digital camera was used for swift detection of fluorescence from the pH sen-sitive dye 6,8-Dihydroxypyrene-1,3-disulfonic acid in real-time. Main principles were demonstrated byautomated continuous measurements of pH in the surface water across the Baltic Sea and the Kattegatregion with a large range in salinity (∼3–30) and temperature (∼0–25◦C). Ship-board precision of salinityand temperature adjusted pH measurements were estimated as low as 0.0001 pH units.
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| 4. |
- Kuklinski, Nicholas J., et al.
(författare)
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Biogenic Amines in Microdissected Brain Regions of Drosophila melanogaster Measured with Mice liar Electrokinetic Capillary Chromatography-Electrochemical Detection
- 2010
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 82:18, s. 7729-7735
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Tidskriftsartikel (refereegranskat)abstract
- Micellar electrokinetic chromatography with electrochemical detection has been used to quantify biogenic amines in microdissected Drosophila melanogaster brains and brain regions. The effects of pigment from the relatively large fly eyes on the separation have been examined to find that the red pigment from the compound eye masks much of the signal from biogenic amines. The brains of white mutant flies, which have characteristically low pigment in the eyes, have a significantly simplified separation profile in comparison to the red-eyed, wild-type, Canton S fly. Yet, the white mutant flies were found to have significantly less amounts of dopamine, I-3,4-dihydroxyphenylalanine (L-DOPA), salsolinol, and N-acetyltyramine in their dissected brains when compared to dissected brains of Canton S flies. In addition, significant variation has been observed in the dissected brains between individual flies that might be related to changes in neurotransmitter turnover. The transgenic GFP fly line (TH-GFP), for which the overall profile of biogenic amines is not found to be significantly different from Canton S, can be used to visualize the location of dopamine neurons. Biogenic amines were then quantified in three brain regions observed to have dopamine levels, the central brain, optic lobes, and posterior superiormedial proto-cerebrum (PPM1) region.
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| 5. |
- Kuklinski, Nicholas J., et al.
(författare)
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Determination of salsolinol, norsalsolinol, and twenty-one biogenic amines using micellar electrokinetic capillary chromatography-electrochemical detection
- 2010
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Ingår i: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 31:11, s. 1886-1893
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Tidskriftsartikel (refereegranskat)abstract
- Micellar electrokinetic chromatography coupled to amperometric electrochemical detection was used to resolve and then quantify biogenic amines and metabolites within the fruit fly Drosophila melanogaster. A new separation scheme was devised to allow resolution of 24 compounds of interest. This was accomplished by precisely controlling the amount of base added to the background buffer, optimizing the resolution of the separation, and then calculating the pH. Here we focused on measurements of six of the analytes that are thought to be involved in the response to alcohol, dopamine, salsolinol, norsalsolinol, N-acetyloctopamine, octopamine, and N-acetyldopamine. These were identified and quantified within the fly head. We believe that the identification of salsolinol and norsalsolinol in the fly brain is novel.
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