| 1. |
- 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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| 2. |
- Li, Yongqiang, 1992, et al.
(författare)
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Assessment of compositional changes of carbonated cement pastes subjected to high temperatures using in-situ Raman mapping and XPS
- 2022
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Ingår i: Journal of Building Engineering. - : Elsevier BV. - 2352-7102. ; 45
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new method for assessing the compositional changes of carbonated cement pastes subjected to high temperatures. In this new method, in-situ Raman mapping combined with X-ray photoelectron spectroscopy (XPS) was used to monitor the phase transformation in carbonated cement pastes subjected to various high temperatures from 30 to 950 degrees C. Two kinds of carbonated areas, i.e., vaterite dominated and calcite dominated, were found in the in-situ Raman measurements. With the elevation in temperature, most of the vaterite was converted to calcite at 500 degrees C and completely decomposed at 600 degrees C, while the decomposition of calcite started at 600 degrees C and finished at 720 degrees C. Meanwhile, the depolymerization of the calcium modified silica gel to the silicate phases with a lower degree of polymerization was initiated at 500 degrees C, which led to the crystallization of beta-C2S at 600 degrees C. The generation of beta-C2S was found to increase with the elevation in temperature and became the dominant phase at 950 degrees C. In conclusion, the high temperature could affect the stability of carbonated cement pastes at 500 degrees C and above. The in-situ Raman mapping measurement has provided an extraordinary view of the spatial distribution of interesting phases subjected to high temperatures in a nondestructive way, which should be more consistent with the true condition in the material.
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| 3. |
- Li, Yongqiang, et al.
(författare)
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Chemical and mineralogical characteristics of carbonated and uncarbonated cement pastes subjected to high temperatures
- 2021
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Ingår i: Composites Part B: Engineering. - : Elsevier BV. - 1359-8368. ; 216
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Tidskriftsartikel (refereegranskat)abstract
- The fire-resistance of carbonated concrete under high temperatures is significant due to its direct exposure during an accidental fire. To evaluate the carbonation effect on fire-resistance of concrete, the chemical and mineralogical changes of uncarbonated and carbonated cement pastes subjected to high temperatures were thoroughly investigated in this research by employing micro-measurement methods including thermal-gravimetric analysis (TGA), X-ray diffraction (XRD) and Si nuclear magnetic resonance ( Si NMR). Uncarbonated cement paste results showed the decomposition of portlandite at 400 °C with the formation of lime, whilst the depolymerization of C–S–H happened simultaneously to generate monomeric silicon tetrahedron. Above 720 °C, all the C–S–H depolymerized to crystalline C S. Carbonated cement pastes on the other hand showed that amorphous calcium carbonate and part of vaterite decomposed between the range of 400–600 °C, while the rest of the vaterite and calcite were decomposed at 600–720 °C. The individual content of calcium carbonate polymorph could not be obtained using a TGA curve. Besides, the calcium-modified silicate gel was significantly decomposed at 500 °C and completely depolymerized to crystalline C S at 950 °C. In summary, carbonated pastes show better resistance to high temperatures with its heat absorption capacity 3.3 times as high as the uncarbonated sample, which delays the temperature development in the inner layer. Therefore, a reasonable carbonation process could help to improve the fire resistance of concrete to some extent.
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| 4. |
- Liu, W., et al.
(författare)
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Changes in chemical phases and microscopic characteristics of fly ash blended cement pastes in different CO 2 concentrations
- 2020
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 257
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Tidskriftsartikel (refereegranskat)abstract
- The effects of CO2 concentration on changes in chemical phases and microscopic characteristics for fly ash (FA) blended cement pastes were investigated in this study. Several microscopic test methods, including X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), 29Si nuclear magnetic resonance (29Si NMR) and scanning electron microscope (SEM), were used to characterize the chemical compositions and microscopic features. The XRD results showed that the precipitation of allotropic calcium carbonate (CC̅) includes calcite (c), aragonite (a) and vaterite (v). The ratio of c/(a + v) was around 0.6 under 3% and 20% CO2, while more percentage of calcite was generated under 100% CO2 (c/(a + v) = 0.79). The precipitation of more calcite than vaterite and aragonite happened with the CO2 concentration elevated to 100%. TGA analysis indicated that the total content of CC̅ was similar under all accelerated conditions and higher than that under natural carbonation. Additionally, in the 29Si NMR spectra, more C-S-H (about 70%) was decalcified after accelerated carbonation compared with natural carbonation (54.1%). The decalcification degree was the same for 3% and 20% CO2 and showed the highest value under 100% CO2. The microstructure changes characterized by SEM observation exhibited denser microstructure after carbonation with the formation of CC̅ but no apparent difference was observed with different CO2 concentrations based on the SEM pictures. Compared with the carbonation of ordinary Portland cement (OPC) paste, the carbonation of FA blended cement paste was more inclined to precipitate as calcite than vaterite and aragonite and caused a lower decalcification degree of C-S-H. Overall, similar to OPC paste, the carbonation results obtained in natural and accelerated conditions for FA blended cement pastes were different and the conditions between 3% and 20% CO2 were similar while 100% CO2 showed different results.
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| 5. |
- Deng, Min, et al.
(författare)
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Genome-wide association analyses in Han Chinese identify two new susceptibility loci for amyotrophic lateral sclerosis
- 2013
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 45:6, s. 697-
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Tidskriftsartikel (refereegranskat)abstract
- To identify susceptibility genes for amyotrophic lateral sclerosis (ALS), we conducted a genome-wide association study (GWAS) in 506 individuals with sporadic ALS and 1,859 controls of Han Chinese ancestry. Ninety top SNPs suggested by the current GWAS and 6 SNPs identified by previous GWAS were analyzed in an independent cohort of 706 individuals with ALS and 1,777 controls of Han Chinese ancestry. We discovered two new susceptibility loci for ALS at 1q32 (CAMK1G, rs6703183, P-combined = 2.92 x 10(-8), odds ratio (OR) = 1.31) and 22p11 (CABIN1 and SUSD2, rs8141797, P-combined = 2.35 x 10(-9), OR = 1.52). These two loci explain 12.48% of the overall variance in disease risk in the Han Chinese population. We found no association evidence for the previously reported loci in the Han Chinese population, suggesting genetic heterogeneity of disease susceptibility for ALS between ancestry groups. Our study identifies two new susceptibility loci and suggests new pathogenic mechanisms of ALS.
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| 6. |
- Li, Yong Qiang, et al.
(författare)
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Carbonation of the synthetic calcium silicate hydrate (C-S-H) under different concentrations of CO2: Chemical phases analysis and kinetics
- 2020
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Ingår i: Journal of CO2 Utilization. - : Elsevier BV. - 2212-9820. ; 35, s. 303-313
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the chemical phases analysis and the kinetics of synthetic calcium silicate hydrate (C-S-H) under differentCO2concentrations (natural (0.03%), 3%, 10%, 20%, 50%, 100%) were investigated. For this aim, the scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed for microstructure characterisation. The 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) coupled with mass spectrometer (MS) were used for characterising the chemical phases before and after carbonation. From the NMR results, it was found that C-S-H would be partly decalcified under the natural condition but completely under the accelerated conditions. Two equations related to the carbonation kinetics under natural and accelerated conditions were proposed respectively. The compositions in decalcified C-S-H were not affected by the CO2 concentration. The XRD analysis showed that vaterite, aragonite and calcite were coexistent after carbonation, which would be transformed to aragonite and calcite with further carbonation. The preferential formation of the allotropic calcium carbonate was not impacted by the concentration of CO2 either. Based on the TGA-MS test, the stoichiometric formula of synthetic C-S-H was determined with CaOâ'™SiO2â'™0.87H2O or Câ Sâ H0.87. In addition, a carbonation kinetics model was proposed to learn the carbonation kinetics of C-S-H carbonated in different CO2 concentrations. The experimental data fitted well with the model. The carbonation kinetics between 3% and 20% CO2 are similar, but different from that under 50% and 100% CO2
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| 7. |
- Liu, Wei, et al.
(författare)
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Slag Blended Cement Paste Carbonation under Different CO(2)Concentrations: Controls on Mineralogy and Morphology of Products
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:15, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the effect of different CO(2)concentrations on the carbonation results of slag blended cement pastes, carbonation experiments under natural (0.03% CO2) and accelerated conditions (3, 20, and 100% CO2) were investigated with various microscopic testing methods, including X-ray diffraction (XRD),Si-29 magic angle spinning nuclear magnetic resonance (Si-29 MAS NMR) and scanning electron microscopy (SEM). The XRD results indicated that the major polymorphs of CaCO(3)after carbonation were calcite and vaterite. The values of the calcite/(aragonite + vaterite) (c/(a + v)) ratios were almost the same in all carbonation conditions. Additionally, NMR results showed that the decalcification degree of C-S-H gel exposed to 0.03% CO(2)was less than that exposed to accelerated carbonation; under accelerated conditions, it increased from 83.1 to 84.2% when the CO(2)concentration improved from 3% to 100%. In SEM observations, the microstructures after accelerated carbonation were denser than those under natural carbonation but showed minor differences between different CO(2)concentrations. In conclusion, for cement pastes blended with 20% slag, a higher CO(2)concentration (above 3%) led to products different from those produced under natural carbonation. A further increase in CO(2)concentration showed limited variation in generated carbonation products.
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| 8. |
- Ren, Jun, et al.
(författare)
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Effect of silica fume on the mechanical property and hydration characteristic of alkali-activated municipal solid waste incinerator (MSWI) fly ash
- 2021
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 295
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Tidskriftsartikel (refereegranskat)abstract
- The incorporation of silica fume provides the solution to solve the low silica content of municipal solid waste incinerator fly ash, which hinders its utilisation in manufacturing alkali-activated solid waste incinerator fly ash. This paper reported the effect of silica fume and sodium silicate nature on the hardened properties, including compressive strength, hydration product and microstructure of alkali-activated municipal solid waste incinerator fly ash. In addition to characterising the property of municipal fly ash, the effect of silica fume in compressive strength of alkali-activated municipal solid waste incinerator fly ash under different sodium silicate dosage and modulus was investigated and its hydration products were determined by XRD and SEM. The results demonstrated that adding silica fume significantly improved the compressive strength by promoting the formation of C–S–H hydration product. Moreover, a higher sodium silicate content and modulus resulted in a higher compressive strength. The concentration of leachable heavy metals from harden specimen with 10% SF specimen was significantly reduced to the value which is much lower than the recommendation from Chinese standards.
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