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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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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.
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| 3. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 5. |
- Yuan, Bo, et al.
(författare)
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Preparation and properties of porous silicon carbide based ceramic filter
- 2016
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 684, s. 613-615
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Tidskriftsartikel (refereegranskat)abstract
- Porous silicon carbide ceramics with high open porosity and large pore size are usually applied as filters for the cleaning of hot dust gases. However, the large porosity and large pore size will decrease the mechanical properties. In the present study, porous SiC ceramics were prepared using bentonite as bonding phase. The effects of sintering temperature on the microstructure and the compressive strength were studied. Bentonite could melt and spread on the surface of silicon carbide particles at all the sintering temperatures. However, the bonding effects were very different at different temperatures.
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| 6. |
- Wang, Dian-Zheng, et al.
(författare)
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Cracking Behavior in Additively Manufactured Pure Tungsten
- 2019
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Ingår i: Acta Metallurgica Sinica (English Letters). - : Springer Science and Business Media LLC. - 1006-7191 .- 2194-1289. ; 32:1, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- In this study, near fully dense (96.5%) pure tungsten bulks were additively manufactured and the cracking behavior was investigated. A crack network with a spacing of similar to 100m was observed in the fabricated bulks. It was observed that the laser scanning strategy, which could tailor the microstructure, affected the crack distribution pattern in fabricated tungsten. The calculated surface temperature difference (7300K) was much higher than the cracking criterion (800K) of tungsten, indicating that cracking is almost inevitable in laser additive manufacturing of tungsten. It could be concluded that crack network formed because the cracks emerged in every laser molten track and then interconnected in the layer-by-layer building process.
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| 7. |
- Xing, Lei-Lei, et al.
(författare)
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Influence of Powder Bed Temperature on the Microstructure and Mechanical Properties of Ti-6Al-4V Alloy Fabricated via Laser Powder Bed Fusion
- 2021
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- Laser powder bed fusion (LPBF) is being increasingly used in the fabrication of complex-shaped structure parts with high precision. It is easy to form martensitic microstructure in Ti-6Al-4V alloy during manufacturing. Pre-heating the powder bed can enhance the thermal field produced by cyclic laser heating during LPBF, which can tailor the microstructure and further improve the mechanical properties. In the present study, all the Ti-6Al-4V alloy samples manufactured by LPBF at different powder bed temperatures exhibit a near-full densification state, with the densification ratio of above 99.4%. When the powder bed temperature is lower than 400 degrees C, the specimens are composed of a single alpha ' martensite. As the temperature elevates to higher than 400 degrees C, the alpha and beta phase precipitate at the alpha ' martensite boundaries by the diffusion and redistribution of V element. In addition, the alpha/alpha ' lath coarsening is presented with the increasing powder bed temperature. The specimens manufactured at the temperature lower than 400 degrees C exhibit high strength but bad ductility. Moreover, the ultimate tensile strength and yield strength reduce slightly, whereas the ductility is improved dramatically with the increasing temperature, when it is higher than 400 degrees C.
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| 8. |
- Xing, Lei-Lei, et al.
(författare)
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Microstructure of a Ti-50 wt% Ta alloy produced via laser powder bed fusion
- 2020
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Ingår i: Acta Metallurgica Sinica (English Letters). - : Springer Science and Business Media LLC. - 1006-7191 .- 2194-1289. ; 33, s. 981-990
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Tidskriftsartikel (refereegranskat)abstract
- Ti-Ta alloys have been widely studied for biomedical applications due to their high biocompatibility and corrosion resistance. In this work, nearly fully dense and in situ alloyed Ti-50 wt% Ta samples were fabricated by the laser powder bed fusion (LPBF) of mechanically mixed powders. With increased exposure time, and thereby increased laser energy density, insoluble Ta particles were almost dissolved, and a Ti-50 wt% Ta alloy was formed. Cellular and dendritic structures were formed due to constitutional undercooling, which was caused by the high cooling rate of LPBF process. Both retained beta phases and alpha '' phases were observed in the LPBFed Ti-50 wt% Ta alloy. The alpha '' phase was found at the boundary of the cellular structures, where the tantalum content was not high enough to suppress the bcc lattice transition completely but could suppress the beta phase -> alpha ' phase transition.
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| 9. |
- Zou, Ji, et al.
(författare)
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Separating macrostresses from microstresses in Al2O3-15 vol%SiC particulate reinforced composites
- 2015
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 109, s. 84-88
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Tidskriftsartikel (refereegranskat)abstract
- Macrostresses and microstresses coexist in ceramics, but are difficult to distinguish. In this work, these two types of residual stresses were separated by comparing the stress levels on the mechanically and argon beam polished surfaces of Al2O3-15 vol%SiC particulate reinforced composites. Stresses were measured using the shift of a Raman peak of beta-sic, the shift of a luminescence line of alpha-Al2O3 and a self-consistent approach. The critical grain size of SiC, over which will result in the crack formation in Al2O3 matrix, was calculated to be 13.5-26.4 mu m. New microcracldng did not form in Al2O3 grains during progressive mechanical polishing.
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| 10. |
- Zou, Ji, et al.
(författare)
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Ultra-low temperature reactive spark plasma sintering of ZrB2-hBN ceramics
- 2016
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 36:15, s. 3637-3645
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Tidskriftsartikel (refereegranskat)abstract
- Starting from ZrN and amorphous boron, dense ZrB2 ceramics with 37 vol% hexagonal BN were consolidated by spark plasma sintering. Benefiting from the moderate exothermic reaction between ZrN and B and the resultant fine powder generated, ZrB2-BN ceramics with relative density of 94% could be reached at 1100 degrees C, further improved to 97% by 1550 degrees C. The effects of sintering temperature and holding time on the densification behavior, microstructural evolution and mechanical properties of ZrB2-BN ceramics were investigated. ZrB2-37 vol%BN ceramics densified at 1700 degrees C exhibited attractive mechanical performance: a three-point bending strength of 353 MPa, a Vicker's hardness of 6.7 GPa and a Young's modulus of 197.5 GPa. Note that its strength dropped sharply to 191 MPa measured at 1300 degrees C. The combination of low sintering temperature (1100-1550 degrees C), low Young's modulus (180-200 GPa) and relatively high strength (200-350 MPa) make reactively sintered ZrB2-BN composites as promising matrix for continuous fiber reinforced composites.
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