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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. |
- Yao, Yunjun, et al.
(författare)
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Estimation of high-resolution terrestrial evapotranspiration from Landsat data using a simple Taylor skill fusion method
- 2017
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 553, s. 508-526
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Tidskriftsartikel (refereegranskat)abstract
- Estimation of high-resolution terrestrial evapotranspiration (ET) from Landsat data is important in many climatic, hydrologic, and agricultural applications, as it can help bridging the gap between existing coarse-resolution ET products and point-based field measurements. However, there is large uncertainty among existing ET products from Landsat that limit their application. This study presents a simple Taylor skill fusion (STS) method that merges five Landsat-based ET products and directly measured ET from eddy covariance (EC) to improve the global estimation of terrestrial ET. The STS method uses a weighted average of the individual ET products and weights are determined by their Taylor skill scores (S). The validation with site-scale measurements at 206 EC flux towers showed large differences and uncertainties among the five ET products. The merged ET product exhibited the best performance with a decrease in the averaged root-mean-square error (RMSE) by 2–5 W/m2 when compared to the individual products. To evaluate the reliability of the STS method at the regional scale, the weights of the STS method for these five ET products were determined using EC ground-measurements. An example of regional ET mapping demonstrates that the STS-merged ET can effectively integrate the individual Landsat ET products. Our proposed method provides an improved high-resolution ET product for identifying agricultural crop water consumption and providing a diagnostic assessment for global land surface models.
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| 4. |
- Bairagi, Samiran, et al.
(författare)
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Formation of quaternary Zn(AlxGa1−x)2O4 epilayers driven by thermally induced interdiffusion between spinel ZnGa2O4 epilayer and Al2O3 substrate
- 2023
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Ingår i: Materials Today Advances. - : Elsevier. - 2590-0498. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Zinc aluminogallate, Zn(AlxGa1−x)2O4 (ZAGO), a single-phase spinel structure, offers considerable potential for high-performance electronic devices due to its expansive compositional miscibility range between aluminum (Al) and gallium (Ga). Direct growth of high-quality ZAGO epilayers however remains problematic due to the high volatility of zinc (Zn). This work highlights a novel synthesis process for high-quality epitaxial quaternary ZAGO thin films on sapphire substrates, achieved through thermal annealing of a ZnGa2O4 (ZGO) epilayer on sapphire in an ambient air setting. In-situ annealing x-ray diffraction measurements show that the incorporation of Al in the ZGO epilayer commenced at 850 °C. The Al content (x) in ZAGO epilayer gradually increased up to around 0.45 as the annealing temperature was raised to 1100 °C, which was confirmed by transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy. X-ray rocking curve measurement revealed a small full width at half maximum value of 0.72 °, indicating the crystal quality preservation of the ZAGO epilayer with a high Al content. However, an epitaxial intermediate �–(AlxGa1−x)2O3 layer (� - AGO) was formed between the ZAGO and sapphire substrate. This is believed to be a consequence of the interdiffusion of Al and Ga between the ZGO thin film and sapphire substrate. Using density functional theory, the substitution cost of Ga in sapphire was determined to be about 0.5 eV lower than substitution cost of Al in ZGO. Motivated by this energetically favorable substitution, a formation mechanism of the ZAGO and AGO layers was proposed. Spectroscopic ellipsometry studies revealed an increase in total thickness of the film from 105.07 nm (ZGO) to 147.97 nm (ZAGO/AGO) after annealing to 1100 °C, which were corroborated using TEM. Furthermore, an observed increase in the direct (indirect) optical bandgap from 5.06 eV (4.7 eV) to 5.72 eV (5.45 eV) with an increasing Al content in the ZAGO layer further underpins the formation of a quaternary ZAGO alloy with a tunable composition.
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| 5. |
- Du, Kun, et al.
(författare)
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Effect of non-axisymmetric endwall contouring and swirling inlet flow on film cooling performance of turbine endwall
- 2024
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Ingår i: International Journal of Heat and Mass Transfer. - 0017-9310. ; 229
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Tidskriftsartikel (refereegranskat)abstract
- Non-axisymmetric endwall contouring (NEC) is one of the verified approaches to suppress secondary flows and improve aerodynamic performance. However, the design of NEC brings significant challenges to the design of endwall cooling structures. Herein, a pressure-sensitive paint experimental approach was used to obtain the film cooling effectiveness of the NEC endwall with a purge slot in this study. Three NEC types were adopted: NEC (COS), NEC (SIN), and NEC (−SIN). In addition, lean premixed combustion technology was used to achieve lower levels of NOx emissions. The turbine inlet was characterized by high turbulence and strong swirling. The effects of different swirling angles (±10, ±20, and ±30°) and densities were further explored. Due to the NEC profiling changing the secondary flow near the endwall area, coolant from the purge slot was better attached to the slot exit position, leading to a significant increase in the size of the high-cooling-efficiency region. With the mass flow ratio (MFR) varying from 0.5 to 2%, the film cooling effectiveness of the flat and NEC endwalls had similar variation characteristics. When the MFR = 0.5%, the area-averaged cooling efficiencies of the NEC (COS), NEC (SIN), and NEC (−SIN) endwalls could be improved by 2, 12.5, and 20%, respectively. Positive swirling and smaller negative swirling inflow could improve the film cooling effectiveness inside the channel. The case of SA = +20° had the best improvement, where the film cooling effectiveness of the NEC (COS), NEC (SIN), and NEC (−SIN) endwalls could reach up to 29, 35, 36, and 34%, respectively. The NEC (−SIN) endwall was less sensitive to the effects of the swirling inflow.
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| 6. |
- Du, Kun, et al.
(författare)
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Non-axisymmetric Endwall film cooling characteristics considering the influences of cylindrical holes and laidback fan-shaped holes
- 2024
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Ingår i: International Journal of Heat and Mass Transfer. - 0017-9310. ; 225
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Tidskriftsartikel (refereegranskat)abstract
- Flow fields near the turbine vane endwall are complicated due to the endwall cross flows. The use of a non-axisymmetric endwall is regarded as an efficient technique to reduce the lateral pressure difference, decreasing the endwall cross flow. Numerical analysis was performed to determine how the non-axisymmetric endwall affected the vortex structure and heat transfer level. The cooling performance was investigated with cylindrical and laidback fan-shaped holes (7–7–7), which were arranged in rows aligned in the axial direction. The results showed that the non-axisymmetric endwall could significantly reduce the circumferential pressure difference and suppress the growth of the passage vortex, and the area-averaged heat transfer coefficient was reduced by 3.34%. The outlet area of the film hole was altered by the non-axisymmetric endwall, and the over-cooled regions may have appeared as a result of the excessive area increase. The influence of the non-axisymmetric endwall was concentrated at 0.4 < Z/Cax < 1.0 for the cylindrical hole. With the increase in M, the film cooling effectiveness of the non-axisymmetric endwall attained a higher level than that of the flat endwall. For the laidback fan-shaped hole, the effect of the non-axisymmetric endwall was confined within 0.25 < Z/Cax < 1.0. The half-period trigonometric function of the non-axisymmetric endwall (HTFN) achieved the optimal cooling performance for three blowing ratios. However, the periodic trigonometric function of the non-axisymmetric endwall (PTFN) only outperformed the flat endwall when M= 1.5.
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| 8. |
- Gu, Yeqing, et al.
(författare)
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Consumption of ultraprocessed food and development of chronic kidney disease : the Tianjin Chronic Low-Grade Systemic Inflammation and Health and UK Biobank Cohort Studies
- 2023
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Ingår i: The American journal of clinical nutrition. - : Elsevier BV. - 1938-3207 .- 0002-9165. ; 117:2, s. 373-382
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMany ultraprocessed food (UPF)-derived by-products may play a role in the development of chronic kidney disease (CKD). Although several studies have assessed the association of UPFs with kidney function decline or CKD in various countries, no evidence has been shown in China and the United Kingdom.ObjectivesThis study aims to evaluate the association between UPF consumption and risk of CKD in 2 large cohort studies from China and the United Kingdom.MethodsIn total, 23,775 and 102,332 participants without baseline CKD were enrolled in the Tianjin Chronic Low-Grade Systemic Inflammation and Health (TCLSIH) and UK Biobank cohort studies, respectively. Information on UPF consumption was obtained from a validated food frequency questionnaire in the TCLSIH and 24-h dietary recalls in the UK Biobank cohort. CKD was defined as an estimated glomerular filtration rate of ResultsAfter a median follow-up of 4.0 and 10.1 y, the incidence rates of CKD were around 1.1% and 1.7% in the TCLSIH and UK Biobank cohorts, respectively. The multivariable hazard ratio [95% confidence interval] of CKD across increasing quartiles (quartiles 1–4) of UPF consumption were 1 (reference), 1.24 (0.89, 1.72), 1.30 (0.91, 1.87), and 1.58 (1.07, 2.34) (P for trend = 0.02) in the TCLSIH cohort and 1 (reference), 1.14 (1.00, 1.31), 1.16 (1.01, 1.33), and 1.25 (1.09, 1.43) (P for trend < 0.01) in the UK Biobank cohort, respectively.ConclusionsOur finding indicated that higher UPF consumption is associated with a higher risk of CKD. Moreover, restricting UPF consumption may potentially benefit the prevention of CKD. Further clinical trials are required to clarify the causality.
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| 9. |
- Jia, Ruo, 1993, et al.
(författare)
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A spatio-temporal deep learning model for short-term bike-sharing demand prediction
- 2023
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Ingår i: Electronic Research Archive. - : American Institute of Mathematical Sciences (AIMS). - 2688-1594. ; 31:2, s. 1031-1047
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Tidskriftsartikel (refereegranskat)abstract
- Bike-sharing systems are widely operated in many cities as green transportation means to solve the last mile problem and reduce traffic congestion. One of the critical challenges in operating high-quality bike-sharing systems is rebalancing bike stations from being full or empty. However, the complex characteristics of spatiotemporal dependency on usage demand may lead to difficulties for traditional statistical models in dealing with this complex relationship. To address this issue, we propose a graph-based neural network model to learn the representation of bike-sharing demand spatial-temporal graph. The model has the ability to use graph-structured data and takes both spatial -and temporal aspects into consideration. A case study about bike-sharing systems in Nanjing, a large city in China, is conducted based on the proposed method. The results show that the algorithm can predict short-term bike demand with relatively high accuracy and low computing time. The predicted errors for the hourly station level usage demand prediction are often within 20 bikes. The results provide helpful tools for short-term usage demand prediction of bike-sharing systems and other similar shared mobility systems.
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| 10. |
- Jia, Ruo, et al.
(författare)
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Environmental impact of shared e-scooters in three Swedish cities : insights from big data
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 334-335
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- E-scooter sharing has rapidly gained popularity in the past few years, but its actual impact on the environment remains unclear despite numerous discussions. Specifically, the environmental impact of shared e-scooters is intrinsically tied to the usage patterns of travelers, and the degree to which shared e-scooters replace other modes of transport. To this end, we collect data in Sweden and develop a universally applicable framework to quantify and evaluate the effects of shared micro-mobility on reducing greenhouse gas (GHG) emissions based on field trip data. Our results suggest that the primary modes replaced by shared e-scooters are walking (64.1%) and public transport (24.7%). A systematic comparison among Swedish cities indicates that, on average, each shared e-scooter trip generates an additional 85g of carbon dioxide when considering the entire life cycle. Our raw dataset consists of trip data of shared e-scooters between 1 January and 31 December 2022, from two companies (TIER and VOI) in Stockholm, Gothenburg, and Malmo, which are the three biggest cities in Sweden. Based on the trip starting timestamp and coordinates and ending coordinates, the replaced transport mode for every single trip of using e-scooter sharing is inferred using a travel behaviour model (i.e., multinomial logit model). Additionally, the GHG emission factors of different transport modes are estimated through life cycle analysis (LCA) considering different life-cycle components such as production, operation, and disposal of shared e-scooters. Afterwards, the emission reduction due to every e-scooter-sharing trip is quantified. Aggregated level analysis considering all trips in a city over a year is conducted as well. Our results suggest that the substituted travel modes will differ from the location and travel distance of the OD pairs in the transportation system. More importantly, the substituted transport by shared scooters matters in terms of reducing GHG emissions. If users use e-scooters for a trip instead of cars that have high emissions, it will generate GHG emission reduction. In our cases, the negative emission reduction is observed in the central regions of urban areas, indicating that shared e-scooters will increase GHG emissions compared to the scenario without e-scooter sharing.
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