| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
Forskningsöversikt (refereegranskat)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.
|
|
| 5. |
- Karki, Khadga Jung, et al.
(författare)
-
Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy.
- 2013
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- Multiple exciton generation (MEG) is a process in which more than one exciton is generated upon the absorption of a high energy photon, typically higher than two times the band gap, in semiconductor nanocrystals. It can be observed experimentally using time resolved spectroscopy such as the transient absorption measurements. Quantification of the MEG yield is usually done by assuming that the bi-exciton signal is twice the signal from a single exciton. Herein we show that this assumption is not always justified and may lead to significant errors in the estimated MEG yields. We develop a methodology to determine proper scaling factors to the signals from the transient absorption experiments. Using the methodology we find modest MEG yields in lead chalcogenide nanocrystals including the nanorods.
|
|
| 6. |
- Lenngren, Nils, et al.
(författare)
-
Multiexciton Absorption Cross Sections of CdSe Nanocrystals at Band-Edge Energy
- 2013
-
Ingår i: XVIIIth International Conference On Ultrafast Phenomena. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 41
-
Konferensbidrag (refereegranskat)abstract
- Picosecond transient absorption signals of two kinds of cadmium selenide quantum dots were measured at various excitation intensities. The average number of excitons per quantum dot was calculated from a Poisson model, which together with kinetic parameters was used to determine exciton population kinetics. Exciton and multiexciton absorption cross sections were determined and analyzed in terms of the electronic states of the quantum dots.
|
|
| 7. |
- Lenngren, Nils, et al.
(författare)
-
Multiexciton Absorption Cross Sections of CdSe Quantum Dots Determined by Ultrafast Spectroscopy
- 2013
-
Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 4:19, s. 3330-3336
-
Tidskriftsartikel (refereegranskat)abstract
- Multiexciton absorption cross sections are important for analysis of a number of experiments, including multiple exciton generation and stimulated emisson. We present a rigorous method to determine these cross sections using transient absorption (TA) measurements. We apply the method to CdSe quantum dots (QDs) and core–shell (CdSe)ZnS QDs. The method involves measuring TA dynamics for various excitation intensities over a broad time range and analyzing the experiments in terms of a kinetic multiexciton model taking into account all contributions to the signal. In this way, we were able to quantify exciton and multiexciton absorption cross sections at different spectral positions. The absorption cross sections decrease with increasing number of excitations, qualitatively in agreement with the state-filling effective mass model but showing a slower decrease. The cross sections for single-exciton to biexciton absorption range between 57 and 99% of the ground to single-exciton cross section.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Zeng, Min, et al.
(författare)
-
Effect of lateral fin profiles on stress performance of internally finned tubes in a high temperature heat exchanger
- 2013
-
Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 50:1, s. 886-895
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal stress of the internally finned bayonet tube used for high temperature heat exchangers is numerically investigated by ANSYS software. Three kinds of lateral fin profiles, namely Z-shape, S-shape and V-shape are studied and compared. The significant temperature gradient and largest Von Mises stress are acquired. The largest stress is still generated in the joint of inner fin and outer tube due to the discontinuous change of the structure. The inner fin and inner tube are proposed to not be welded together to meet the reliability. The Z-shape has the best performance in both heat transfer and reliability, and is recommended for engineering application in high temperature heat exchangers. (C) 2012 Elsevier Ltd. All rights reserved.
|
|
