| 1. |
- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Schmidt, Florian M., et al.
(author)
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Direct detection of acetylene in air by continuous wave cavity ring-down spectroscopy
- 2010
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In: Applied physics. B, Lasers and optics (Print). - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 101:3, s. 671-682
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Journal article (peer-reviewed)abstract
- Diode laser-based continuous wave cavity ring-down spectroscopy (cw-CRDS) in the near-infrared region has been used to measure the mixing ratio of acetylene (C(2)H(2)) in ambient air. Detection limits of 120 parts per trillion by volume (pptv) for 20 min and 340 pptv for 70 s acquisition time were achieved without sample pre-concentration, measuring on a C(2)H(2) absorption line at 6565.620 cm(-1) (similar to 1523 nm). Several indoor and outdoor air samples were collected at different locations in the Helsinki metropolitan area and analyzed using static-cell measurements. In addition, flow measurements of indoor and outdoor air have been performed continuously over several days with a time resolution of down to one minute. Baseline acetylene levels in the range of 0.4 to 3 parts per billion by volume (ppbv), with a maximum around midday and a minimum during the night, were measured. Sudden high mixing ratios of up to 60 ppbv were observed in outdoor air during daytime on a minute time scale. In general, the indoor mixing ratios were found to be higher than those in outdoor air. The acetylene levels correlated with the ambient CO levels and with outdoor temperature.
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| 3. |
- Schmidt, Florian, et al.
(author)
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Ammonia in breath and emitted from skin
- 2013
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 7:1
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Journal article (peer-reviewed)abstract
- Ammonia concentrations in exhaled breath (eNH(3)) and skin gas of 20 healthy subjects were measured on-line with a commercial cavity ring-down spectrometer and compared to saliva pH and plasma ammonium ion (NH4+), urea and creatinine concentrations. Special attention was given to mouth, nose and skin sampling procedures and the accurate quantification of ammonia in humid gas samples. The obtained median concentrations were 688 parts per billion by volume (ppbv) for mouth-eNH(3), 34 ppbv for nose-eNH3, and 21 ppbv for both mouth-and nose-eNH(3) after an acidic mouth wash (MW). The median ammonia emission rate from the lower forearm was 0.3 ng cm(-2) min(-1). Statistically significant (p < 0.05) correlations between the breath, skin and plasma ammonia/ammonium concentrations were not found. However, mouth-eNH(3) strongly (p < 0.001) correlated with saliva pH. This dependence was also observed in detailed measurements of the diurnal variation and the response of eNH(3) to the acidic MW. It is concluded that eNH(3) as such does not reflect plasma but saliva and airway mucus NH4+ concentrations and is affected by saliva and airway mucus pH. After normalization with saliva pH using the Henderson-Hasselbalch equation, mouth-eNH(3) correlated with plasma NH4+, which points to saliva and plasma NH4+ being linked via hydrolysis of salivary urea.
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| 4. |
- Schleeh, Joel, 1986, et al.
(author)
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Passivation of InGaAs/InAlAs/InP HEMTs using Al2O3 atomic layer deposition
- 2011
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In: Conference Proceedings - International Conference on Indium Phosphide and Related Materials. 2011 Compound Semiconductor Week and 23rd International Conference on Indium Phosphide and Related Materials, CSW/IPRM 2011, Berlin, 22-26 May 2011. - 1092-8669. - 9781457717536
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Conference paper (peer-reviewed)abstract
- InGaAs/InAlAs/InP HEMTs (InP HEMTs) passivated by Al2O3 atomic layer deposition (ALD) demonstrated improved DC performance compared to Si3N4 plasma enhanced chemical vapour deposition (PECVD). DC measurements have been performed on 130 nm gate-length devices before and after passivation. An increase in maximum drain current density of 20% and extrinsic transconductance of 30% were observed after both ALD and PECVD device passivation. In comparison to PECVD passivated InP HEMTs, ALD passivated devices demonstrated a full suppression of a kink in the I-V characteristics associated with surface traps.
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| 5. |
- Carlsson, C., et al.
(author)
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High-frequency analog modulation of oxide confined 670-nm vertical-cavity surface-emitting lasers
- 2004
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In: Optical Engineering. - : SPIE-Intl Soc Optical Eng. - 0091-3286 .- 1560-2303. ; 43:12, s. 3138-3141
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Journal article (peer-reviewed)abstract
- We investigate the bandwidth limitations and the analog modulation characteristics at microwave frequencies (0.1 to 10 GHz)of a low-capacitance oxide-confined 670-nm InGaAIP vertical-cavity surface-emitting laser (VCSEL). A maximum modulation bandwidth of 6.3 GHz, limited by thermal effects, is achieved. From measurements of distortion and noise, a spurious free dynamic range (SFDR) of 100 dB Hz(2/3) is obtained at frequencies up to 2 GHz, rendering such VCSELs useful for transmission of analog signals. At higher frequencies, the SFDR drops due to the thermally limited resonance frequency.
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