| 1. |
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| 2. |
- 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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| 3. |
- 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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| 4. |
- Kristanl, Matej, et al.
(författare)
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The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
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Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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| 5. |
- Jarvis, Erich D., et al.
(författare)
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Whole-genome analyses resolve early branches in the tree of life of modern birds
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1320-1331
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Tidskriftsartikel (refereegranskat)abstract
- To better determine the history of modern birds, we performed a genome-scale phylogenetic analysis of 48 species representing all orders of Neoaves using phylogenomic methods created to handle genome-scale data. We recovered a highly resolved tree that confirms previously controversial sister or close relationships. We identified the first divergence in Neoaves, two groups we named Passerea and Columbea, representing independent lineages of diverse and convergently evolved land and water bird species. Among Passerea, we infer the common ancestor of core landbirds to have been an apex predator and confirm independent gains of vocal learning. Among Columbea, we identify pigeons and flamingoes as belonging to sister clades. Even with whole genomes, some of the earliest branches in Neoaves proved challenging to resolve, which was best explained by massive protein-coding sequence convergence and high levels of incomplete lineage sorting that occurred during a rapid radiation after the Cretaceous-Paleogene mass extinction event about 66 million years ago.
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| 6. |
- Kristan, Matej, et al.
(författare)
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The first visual object tracking segmentation VOTS2023 challenge results
- 2023
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Ingår i: 2023 IEEE/CVF International conference on computer vision workshops (ICCVW). - : Institute of Electrical and Electronics Engineers Inc.. - 9798350307443 - 9798350307450 ; , s. 1788-1810
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking Segmentation VOTS2023 challenge is the eleventh annual tracker benchmarking activity of the VOT initiative. This challenge is the first to merge short-term and long-term as well as single-target and multiple-target tracking with segmentation masks as the only target location specification. A new dataset was created; the ground truth has been withheld to prevent overfitting. New performance measures and evaluation protocols have been created along with a new toolkit and an evaluation server. Results of the presented 47 trackers indicate that modern tracking frameworks are well-suited to deal with convergence of short-term and long-term tracking and that multiple and single target tracking can be considered a single problem. A leaderboard, with participating trackers details, the source code, the datasets, and the evaluation kit are publicly available at the challenge website1
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| 7. |
- Han, Ning, et al.
(författare)
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Rational design of Ruddlesden–Popper perovskite electrocatalyst for oxygen reduction to hydrogen peroxide
- 2022
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Ingår i: SusMat. - : Wiley. - 2766-8479 .- 2692-4552. ; 2:4, s. 456-465
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Tidskriftsartikel (refereegranskat)abstract
- Although the oxygen reduction process to hydrogen peroxide (H2O2) is a green option for H2O2 generation, the low activity and selectivity hindered the industry's process. In recent years, the electrochemical synthesis of H2O2 through a 2e– transfer method of oxygen reduction reaction (ORR) has piqued the interest of both academics and industry. Metal oxide catalysts have emerged as a novel family of electrochemical catalysts due to their unusual physical, chemical, and electrical characteristics. In this work, we first developed a Ruddlesden–Popper perovskite oxide (Pr2NiO4+δ) as a highly selective and active catalyst for 2e– ORR to produce H2O2. Molybdenum was introduced here to adjust the oxidation states of these transition metals with successful substitution into Ni-site to prepare Pr2Ni1-xMoxO4+δ, and the molybdenum substitution improves the H2O2 selectivity during the ORR process, in 0.1 M KOH, from 60% of Pr2NiO4+δ to 79% of Pr2Ni0.8Mo0.2O4+δ at 0.55 V versus RHE. A limiting H2O2 concentration of 0.24 mM for Pr2NiO4+δ and 0.42 mM for Pr2Ni0.8Mo0.2O4+δ was obtained at a constant current of 10 mA/cm2 using a flow-cell reactor using a gas-diffusion electrode.
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| 8. |
- Xia, Zhisheng, et al.
(författare)
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Fabrication and Tribological Properties of Nickel-Based Cellular Structure Self-Lubricating Composites by Selective Laser Melting and Metal Infiltration
- 2023
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Ingår i: Tribology Transactions. - 1040-2004 .- 1547-397X. ; 66:4, s. 670-682
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Tidskriftsartikel (refereegranskat)abstract
- The service life of Inconel 718 (IN718) nickel-based superalloys under extreme working conditions is limited due to their poor tribological properties. In this study, IN718 cellular structure self-lubricating composites were fabricated by selective laser melting (SLM) and multi-soft metal (Sn-Pb-Ag) infiltration. Different cellular structures were verified by means of numerical simulation and experiment. The effects of pore diameter and temperature on tribological properties of the selective-laser-melted (SLMed) IN718 with Sn-Pb-Ag (INSPA) infiltration self-lubricating composites were investigated. Results show that INSPA samples of cellular structure with a pore diameter of 1.4 mm (INSPA3) exhibited excellent tribological properties compared to the two other pore diameters of 1.2 mm (INSPA2) and 1.0 mm (INSPA1). The tribological properties test results at different temperatures indicate that the coefficient of friction (COF) of INSPA3 was decreased from 0.29 to 0.13 as the temperature of 25 °C rose to 350 °C. The reason is that more Sn-Pb-Ag lubricant was stored in the Ф1.4-mm holes, which were heated and expanded to the worn surface during the friction process to realize self-compensation lubrication. At 350 °C, the friction product of Pb2O was decomposed into PbO and other multicomponent friction oxides were generated, which improves the wear resistance of the SLMed INSPA self-lubricating composites. This study demonstrates a potential approach to enhance the tribological properties and service life of IN718 superalloys used in harsh friction conditions.
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| 9. |
- Zhao, Juan, et al.
(författare)
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A cross-sectional study on upright heart rate and BP changing characteristics: basic data for establishing diagnosis of postural orthostatic tachycardia syndrome and orthostatic hypertension
- 2015
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Ingår i: BMJ Open. - : BMJ Publishing Group: Open Access / BMJ Journals. - 2044-6055. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We aimed to determine upright heart rate and blood pressure (BP) changes to suggest diagnostic criteria for postural orthostatic tachycardia syndrome (POTS) and orthostatic hypertension (OHT) in Chinese children. Methods: In this cross-sectional study, 1449 children and adolescents aged 6-18 years were randomly recruited from two cities in China, Kaifeng in Henan province and Anguo in Hebei province. They were divided into two groups: 844 children aged 6-12 years (group I) and 605 adolescents aged 13-18 years (group II). Heart rate and BP were recorded during an active standing test. Results: 95th percentile (P-95) of delta heart rate from supine to upright was 38 bpm, with a maximum upright heart rate of 130 and 124 bpm in group I and group II, respectively. P-95 of delta systolic blood pressure (SBP) increase was 18 mm Hg and P-95 of upright SBP was 132 mm Hg in group I and 138 mm Hg in group II. P-95 of delta diastolic blood pressure (DBP) increase was 24 mm Hg in group I and 21 mm Hg in group II, and P-95 of upright DBP was 89 mm Hg in group I and 91 mm Hg in group II. Conclusions: POTS is suggested when delta heart rate is greater than= 38 bpm (for easy memory, greater than= 40 bpm) from supine to upright, or maximum heart rate greater than= 130 bpm (children aged 6-12 years) and greater than= 125 bpm (adolescents aged 13-18 years), associated with orthostatic symptoms. OHT is suggested when delta SBP (increase) is greater than= 20 mm Hg, and/or delta DBP (increase) greater than= 25 mm Hg (in children aged 6-12 years) or greater than= 20 mm Hg (in adolescents aged 13-18 years) from supine to upright; or upright BP greater than= 130/90 mm Hg (in children aged 6-12 years) or greater than= 140/90 mm Hg (in adolescents aged 13-18 years).
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| 10. |
- Asayama, Kei, et al.
(författare)
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Setting Thresholds to Varying Blood Pressure Monitoring Intervals Differentially Affects Risk Estimates Associated With White-Coat and Masked Hypertension in the Population
- 2014
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Ingår i: Hypertension. - 0194-911X .- 1524-4563. ; 64:5, s. 935-942
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Tidskriftsartikel (refereegranskat)abstract
- Outcome-driven recommendations about time intervals during which ambulatory blood pressure should be measured to diagnose white-coat or masked hypertension are lacking. We cross-classified 8237 untreated participants (mean age, 50.7 years; 48.4% women) enrolled in 12 population studies, using >= 140/>= 90, >= 130/>= 80, >= 135/>= 85, and >= 120/>= 70 mm Hg as hypertension thresholds for conventional, 24-hour, daytime, and nighttime blood pressure. White-coat hypertension was hypertension on conventional measurement with ambulatory normotension, the opposite condition being masked hypertension. Intervals used for classification of participants were daytime, nighttime, and 24 hours, first considered separately, and next combined as 24 hours plus daytime or plus nighttime, or plus both. Depending on time intervals chosen, white-coat and masked hypertension frequencies ranged from 6.3% to 12.5% and from 9.7% to 19.6%, respectively. During 91 046 person-years, 729 participants experienced a cardiovascular event. In multivariable analyses with normotension during all intervals of the day as reference, hazard ratios associated with white-coat hypertension progressively weakened considering daytime only (1.38; P=0.033), nighttime only (1.43; P=0.0074), 24 hours only (1.21; P=0.20), 24 hours plus daytime (1.24; P=0.18), 24 hours plus nighttime (1.15; P=0.39), and 24 hours plus daytime and nighttime (1.16; P=0.41). The hazard ratios comparing masked hypertension with normotension were all significant (P<0.0001), ranging from 1.76 to 2.03. In conclusion, identification of truly low-risk white-coat hypertension requires setting thresholds simultaneously to 24 hours, daytime, and nighttime blood pressure. Although any time interval suffices to diagnose masked hypertension, as proposed in current guidelines, full 24-hour recordings remain standard in clinical practice.
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