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Sökning: WFRF:(Li Zhenyu)

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1.
  • Beal, Jacob, et al. (författare)
  • Robust estimation of bacterial cell count from optical density
  • 2020
  • Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
  • 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.
  • Kristanl, Matej, et al. (författare)
  • The Seventh Visual Object Tracking VOT2019 Challenge Results
  • 2019
  • Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
  • 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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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.
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5.
  • Jarvis, Erich D., et al. (författare)
  • Whole-genome analyses resolve early branches in the tree of life of modern birds
  • 2014
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1320-1331
  • 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)
  • The first visual object tracking segmentation VOTS2023 challenge results
  • 2023
  • Ingår i: 2023 IEEE/CVF International conference on computer vision workshops (ICCVW). - : Institute of Electrical and Electronics Engineers Inc.. - 9798350307443 - 9798350307450 ; , s. 1788-1810
  • 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.
  • Kristan, Matej, et al. (författare)
  • The Visual Object Tracking VOT2015 challenge results
  • 2015
  • Ingår i: Proceedings 2015 IEEE International Conference on Computer Vision Workshops ICCVW 2015. - : IEEE. - 9780769557205 ; , s. 564-586
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking challenge 2015, VOT2015, aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 62 trackers are presented. The number of tested trackers makes VOT 2015 the largest benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the appendix. Features of the VOT2015 challenge that go beyond its VOT2014 predecessor are: (i) a new VOT2015 dataset twice as large as in VOT2014 with full annotation of targets by rotated bounding boxes and per-frame attribute, (ii) extensions of the VOT2014 evaluation methodology by introduction of a new performance measure. The dataset, the evaluation kit as well as the results are publicly available at the challenge website(1).
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8.
  • Kristan, Matej, et al. (författare)
  • The Visual Object Tracking VOT2016 Challenge Results
  • 2016
  • Ingår i: COMPUTER VISION - ECCV 2016 WORKSHOPS, PT II. - Cham : SPRINGER INT PUBLISHING AG. - 9783319488813 - 9783319488806 ; , s. 777-823
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking challenge VOT2016 aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 70 trackers are presented, with a large number of trackers being published at major computer vision conferences and journals in the recent years. The number of tested state-of-the-art trackers makes the VOT 2016 the largest and most challenging benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the Appendix. The VOT2016 goes beyond its predecessors by (i) introducing a new semi-automatic ground truth bounding box annotation methodology and (ii) extending the evaluation system with the no-reset experiment.
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9.
  • Felsberg, Michael, 1974-, et al. (författare)
  • The Thermal Infrared Visual Object Tracking VOT-TIR2016 Challenge Results
  • 2016
  • Ingår i: Computer Vision – ECCV 2016 Workshops. ECCV 2016.. - Cham : SPRINGER INT PUBLISHING AG. - 9783319488813 - 9783319488806 ; , s. 824-849
  • Konferensbidrag (refereegranskat)abstract
    • The Thermal Infrared Visual Object Tracking challenge 2016, VOT-TIR2016, aims at comparing short-term single-object visual trackers that work on thermal infrared (TIR) sequences and do not apply pre-learned models of object appearance. VOT-TIR2016 is the second benchmark on short-term tracking in TIR sequences. Results of 24 trackers are presented. For each participating tracker, a short description is provided in the appendix. The VOT-TIR2016 challenge is similar to the 2015 challenge, the main difference is the introduction of new, more difficult sequences into the dataset. Furthermore, VOT-TIR2016 evaluation adopted the improvements regarding overlap calculation in VOT2016. Compared to VOT-TIR2015, a significant general improvement of results has been observed, which partly compensate for the more difficult sequences. The dataset, the evaluation kit, as well as the results are publicly available at the challenge website.
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10.
  • Wang, Fang, et al. (författare)
  • Emerging contaminants: A One Health perspective
  • 2024
  • Ingår i: Innovation. - 2666-6758. ; 5
  • Forskningsöversikt (refereegranskat)abstract
    • Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.
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11.
  • Zhang, Kaicheng, et al. (författare)
  • SN 2014J in M82 : new insights on the spectral diversity of Type Ia supernovae
  • 2018
  • Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 481:1, s. 878-893
  • Tidskriftsartikel (refereegranskat)abstract
    • We present extensive spectroscopic observations for one of the closest Type Ia supernovae (SNe Ia), SN 2014J discovered in M82, ranging from 10.4 d before to 473.2 d after B-band maximum light. The diffuse interstellar band features detected in a high-resolution spectrum allow an estimate of line-of-sight extinction as A(v) similar to 1.9 +/- 0.6 mag. Spectroscopically, SN 2014J can be put into the high-velocity (HV) subgroup in Wang's classification with a velocity of Si II lambda 6355 at maximum light of upsilon(0) = 1.22 +/- 0.01 x 10(4) km s(-1) but has a low velocity gradient (LVG, following Benetti's classification) of (v) over bar = 41 +/- 2 km s(-1) d(-1), which is inconsistent with the trend that HV SNe Ia generally have larger velocity gradients. We find that the HV SNe Ia with LVGs tend to have relatively stronger Si III (at similar to 4400 angstrom) absorptions in early spectra, larger ratios of S II lambda 5468 to S II lambda 5640, and weaker Si II 5972 absorptions compared to their counterparts with similar velocities but high velocity gradients. This shows that the HV+ LVG subgroup of SNe Ia may have intrinsically higher photospheric temperature, which indicates that their progenitors may experience more complete burning in the explosions relative to the typical HV SNe Ia.
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12.
  • Qi, Zhenyu, et al. (författare)
  • Blueshifting the Absorption of a Small -Molecule Donor and Using it as the Third Component to Achieve High-Efficiency Ternary Organic Solar Cells
  • 2022
  • Ingår i: Solar RRL. - : WILEY-V C H VERLAG GMBH. - 2367-198X. ; 6:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Adding a small-molecule donor (SMD) to state-of-the-art nonfullerene organic solar cells (OSCs) is demonstrated as a useful strategy to construct ternary organic solar cells, as SMDs typically have high crystallinity and can tune charge transport properties of OSCs. However, the absorption of most SMDs overlaps with typical donor polymers (e.g., PM6), which is against the general guidelines of adopting materials with complementary absorption in ternary OSCs. Herein, the absorption of state-of-art SMDs (BTR-CI) by linking the beta position of the outer thiophene to the alpha position of the inner thiophene unit is intentionally blueshifted. The resulting molecule beta-S1 shows a maximum absorption peak at 505 nm in the film state, which exhibits wider bandgap and shows complementary absorption with the host system (PM6:Y6). The corresponding ternary OSCs with 20%wt beta-S1 show significantly enhanced efficiency from 16.2% to 17.1% due to the increased short-circuit current (J(sc)) and improved fill factor (FF). Herein, an effective strategy to design SMDs with both wider bandgaps and higher crystallinity for high-performance ternary OSCs is presented.
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13.
  • Yang, Li, et al. (författare)
  • Premixed jet flame characteristics of syngas using OH planar laser induced fluorescence
  • 2011
  • Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 56:26, s. 2862-2868
  • Tidskriftsartikel (refereegranskat)abstract
    • Lean premixed flame characteristics of several typical low calorific value (LCV) syngases (basis CO/H-2/CH4/CO2/N-2), including bituminous coal, wood residue, corn core, and wheat straw gasification syngas, were investigated using OH planar laser induced fluorescence (PLIF) technology. OH radical distributions within the turbulent flame were measured for different turbulence intensities. Flame structures of syngases were analyzed and characterized with respect to burnt and unburnt regions, flame curvature (sharp cusp), local extinction (holes and penetration), OH reaction layer thickness, wrinkling, and other features, with OH-PLIF instantaneous images and statistical analysis. Results show that H-2 content, LCV, and turbulence intensity are the most effective factors influencing the OH radical intensity and thickness of OH radical layers. The bituminous coal gasification syngas with relatively higher LCV and H-2 content tends to burn out easily. Through changes in thickness of the OH radical layers and signal intensities, the reaction layer can be compressed by intensifying turbulence and thereby the combustion processes of syngas.
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14.
  • Asayama, Kei, et al. (författare)
  • Setting Thresholds to Varying Blood Pressure Monitoring Intervals Differentially Affects Risk Estimates Associated With White-Coat and Masked Hypertension in the Population
  • 2014
  • Ingår i: Hypertension. - 0194-911X .- 1524-4563. ; 64:5, s. 935-942
  • 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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15.
  • Franklin, Stanley S., et al. (författare)
  • The Cardiovascular Risk of White-Coat Hypertension
  • 2016
  • Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 68:19, s. 2033-2043
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND The role of white-coat hypertension (WCH) and the white-coat-effect (WCE) in development of cardiovascular disease (CVD) risk remains poorly understood. OBJECTIVES Using data from the population-based, 11-cohort IDACO (International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes), this study compared daytime ambulatory blood pressure monitoring with conventional blood pressure measurements in 653 untreated subjects with WCH and 653 normotensive control subjects. METHODS European Society Hypertension guidelines were used as a 5-stage risk score. Low risk was defined as 0 to 2 risk factors, and high risk was defined as >= 3 to 5 risk factors, diabetes, and/or history of prior CVD events. Age-and cohort-matching was done between 653 untreated subjects with WCH and 653 normotensive control subjects. RESULTS In a stepwise linear regression model, systolic WCE increased by 3.8 mm Hg (95% confidence interval [CI]: 3.1 to 4.6 mm Hg) per 10-year increase in age, and was similar in low-and high-risk subjects with or without prior CVD events. Over a median 10.6-year follow-up, incidence of new CVD events was higher in 159 high-risk subjects with WCH compared with 159 cohort-and age-matched high-risk normotensive subjects (adjusted hazard ratio [HR]: 2.06; 95% CI: 1.10 to 3.84; p = 0.023). The HR was not significant for 494 participants with low-risk WCH and age-matched low-risk normotensive subjects. Subgroup analysis by age showed that an association between WCH and incident CVD events is limited to older (age >= 60 years) high-risk WCH subjects; the adjusted HR was 2.19 (95% CI: 1.09 to 4.37; p = 0.027) in the older high-risk group and 0.88 (95% CI: 0.51 to 1.53; p = 0.66) in the older low-risk group (p for interaction = 0.044). CONCLUSIONS WCE size is related to aging, not to CVD risk. CVD risk in most persons with WCH is comparable to age-and risk-adjusted normotensive control subjects.
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16.
  • Klionsky, Daniel J., et al. (författare)
  • Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
  • 2008
  • Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
  • Forskningsöversikt (refereegranskat)abstract
    • Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is 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 verify an autophagic response.
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17.
  • Li, Han, et al. (författare)
  • Advancements of nature nanocage protein : preparation, identification and multiple applications of ferritins
  • 2022
  • Ingår i: Critical reviews in food science and nutrition. - : Informa UK Limited. - 1040-8398 .- 1549-7852. ; 62:25, s. 7117-7128
  • Forskningsöversikt (refereegranskat)abstract
    • Ferritin is an important iron storage protein, which is widely existed in all forms of life. Ferritin can regulate iron homeostasis when iron ions are lacking or enriched in the body, so as to avoid iron deficiency diseases and iron poisoning. Ferritin presents a hollow nanocage, which can store ions or other small molecular substances in the cavity. Therefore, ferritin shows its potential as a functional nanomaterial that can deliver nutrients or drugs in a targeted manner to improve bioavailability. Due to the special structure, the research on ferritin has attracted more and more attention in recent years. In this paper, the structural characteristics of ferritin were introduced, and the natural purification and prokaryotic expression methods of ferritin from different sources were described. At the same time, ferritin can bind to small molecules, so that it has the activity of small molecules, to construct a new type of ferritin. As a result, ferritin plays an important role as a nutrient substance, in targeted transport, and disease monitoring, etc. In conclusion, the yield of ferritin can be improved by means of molecular biology. Meanwhile, molecular modification can be used to make ferritin have unique activity and function, which lays a foundation for subsequent research.
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18.
  • Li, Han, et al. (författare)
  • Improvement of thermal stability of oyster (Crassostrea gigas) ferritin by point mutation
  • 2021
  • Ingår i: Food Chemistry. - : Elsevier. - 0308-8146 .- 1873-7072. ; 346
  • Tidskriftsartikel (refereegranskat)abstract
    • Ferritin can be widely used as functional nanomaterial. But the physiological activity of ferritin can be damaged under excessive temperatures, which affect the self-assembly property. In this study, point mutation was produced in Asp120 to Gly120 of ferritin amino acid sequence and the heat resistance was improved significantly. The thermal denaturation temperature of mutated ferritin is 89.17 degrees C and has increased by 13 degrees C more than the wildtype oyster ferritin. The effect of thermal treatment on the denaturation, aggregation state, particle size and the structure of ferritin was not changed before 90 degrees C. The computational modeling and analysis indicated that mutated ferritin promotes the overall structural stability assembly via decreasing the interaction energies of 62 percent energies in 3-fold interface. Improving the thermal stability of oyster ferritin by point mutation enhances its applications as a food ingredient.
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19.
  • Li, Xin, et al. (författare)
  • Halide Double Perovskite Nanocrystals Doped with Rare-Earth Ions for Multifunctional Applications
  • 2023
  • Ingår i: Advanced Science. - 2198-3844. ; 10:20
  • Tidskriftsartikel (refereegranskat)abstract
    • Most lead-free halide double perovskite materials display low photoluminescence quantum yield (PLQY) due to the indirect bandgap or forbidden transition. Doping is an effective strategy to tailor the optical properties of materials. Herein, efficient blue-emitting Sb3+-doped Cs2NaInCl6 nanocrystals (NCs) are selected as host, rare-earth (RE) ions (Sm3+, Eu3+, Tb3+, and Dy3+) are incorporated into the host, and excellent PLQY of 80.1% is obtained. Femtosecond transient absorption measurement found that RE ions not only served as the activator ions but also filled the deep vacancy defects. Anti-counterfeiting, optical thermometry, and white-light-emitting diodes (WLEDs) are exhibited using these RE ions-doped halide double perovskite NCs. For the optical thermometry based on Sm3+-doped Cs2NaInCl6:Sb3+ NCs, the maximum relative sensitivity is 0.753% K−1, which is higher than those of most temperature-sensing materials. Moreover, the WLED fabricated by Sm3+-doped Cs2NaInCl6:Sb3+ NCs@PMMA displays CIE color coordinates of (0.30, 0.28), a luminous efficiency of 37.5 lm W−1, a CCT of 8035 K, and a CRI over 80, which indicate that Sm3+-doped Cs2NaInCl6:Sb3+ NCs are promising single-component white-light-emitting phosphors for next-generation lighting and display technologies. 
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21.
  • Li, Zhenyu, et al. (författare)
  • How Graphene is Cut upon Oxidation?
  • 2009
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:18, s. 6320-6321
  • Tidskriftsartikel (refereegranskat)abstract
    • Our first principles calculations reveal that an oxidative cut of graphene is realized by forming epoxy and then carbonyl pairs. Direct formation of a carbonyl pair to tear graphene up from an edge position is not favorable in energy. This atomic picture is valuable for developing effective means of graphene manipulation. The proposed epoxy pairs may be related to some long puzzling experimental observations on graphene oxide.
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22.
  • Li, Zhenyu, et al. (författare)
  • mmWave Coverage Extension Using Reconfigurable Intelligent Surfaces in Indoor Dense Spaces
  • 2023
  • Ingår i: ICC 2023 - IEEE International Conference on Communications. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 5805-5810
  • Konferensbidrag (refereegranskat)abstract
    • In this work, we consider the deployment of reconfigurable intelligent surfaces (RISs) to extend the coverage of a millimeter-wave (mmWave) network in indoor dense spaces. We first integrate RIS into ray-tracing simulations to realistically capture the propagation characteristics, then formulate a non-convex optimization problem that minimizes the number of RISs under rate constraints. We propose a feasible point pursuit and successive convex approximation-based algorithm, which solves the problem by jointly selecting the RIS locations, optimizing the RIS phase-shifts, and allocating time resources to user equipments (UEs). The numerical results demonstrate substantial coverage extension by using at least four RISs, and a data rate of 130 Mbit/s is guaranteed for UEs in the considered area of an airplane cabin.
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23.
  • Liang, Zhenyu, et al. (författare)
  • The influence factors of the stability of tailings dam based on multi-source information fusion method
  • 2019
  • Ingår i: Journal of Intelligent & Fuzzy Systems. - : IOS PRESS. - 1064-1246 .- 1875-8967. ; 37:3, s. 3365-3372
  • Tidskriftsartikel (refereegranskat)abstract
    • The BP neural network algorithm is used to construct a stable slope angle prediction model for open-pit mines, which can successfully predict the ultimate slope angle of the mine. At the same time, a multi-tool combination of Surpac, Madis, and Flac3D is used to create a numerical model for stable slope angle in mines. The model is used to test the final slope angle prediction structure for stable mines. Through a comprehensive analysis of the ore deposit model technology constructed by the series of realms, the economic parameters involved in the generation of realm boundaries are known, and specific primaries are pointed out with the error requirements of each parameter analyzed in the realm of series. A concrete solution is put forward to the issue of realm gap. From the point of view of the power and responsibility parameters, the series of realm production methods are analyzed, and the rapid generation methods of the realm of open-pit mine series are pointed out.
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24.
  • Lu, Yingying, et al. (författare)
  • Telomere dysfunction promotes small vessel vasculitis via the LL37-NETs-dependent mechanism
  • 2020
  • Ingår i: Annals of Translational Medicine. - : AME PUBL CO. - 2305-5839 .- 2305-5847. ; 8:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Small vessel vasculitis (SVV) is a group of systemic autoimmune diseases that are mediated by neutrophil extracellular traps (NETs) in response to cathelicidin LL37, an aging molecular marker, which could be induced by telomere dysfunction. Therefore, in this study, we evaluated the hypothesis that telomere dysfunction in neutrophils may promote SVV via an LL37-NETs-dependent mechanism. Methods: We contrasted the release of neutrophil NETs from mice with telomere dysfunction, mice with DNA damage and wide-type mice. Neutrophil telomere length, the expression of LL37, and the formation of NETs were measured in SVV patients and healthy controls (HCs). The co-expression of gamma H2AX, LL37, and NETs were detected in SVV patients to evaluate the association of the immune aging of neutrophils and pro-inflammatory conditions. LL37 inhibitor was used to verify its key role in NETs release in SVV patients and DNA damage mice. Results: We found that NETs were over-induced by telomere dysfunction and DNA damage in mice, which may be associated with a marked increase in LL37. For patients with SVV, telomeres in neutrophils were significantly shortened, which was also associated with higher levels of LL37 and NETs. Inhibition of LL37 reduced the NETs released from neutrophils. Conclusions: Taken together, the results of these studies suggest that dysfunction of telomeres may promote SVV through the mechanism of LL37-dependent NETs. Thus, targeting the LL37-NETs may be a novel therapy for SVV.
  •  
25.
  • Ning, Rui, et al. (författare)
  • Assessing progression limits in different grades of keratoconus from a novel perspective : precision of measurements of the corneal epithelium
  • 2024
  • Ingår i: Eye and Vision. - 2326-0254. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: To assess repeatability and reproducibility of corneal epithelium thickness (ET) measured by a spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39, CSO, Florence, Italy) in keratoconus (KC) population at different stages, as well as to determine the progression limits for evaluating KC progression. Methods: A total of 149 eyes were enrolled in this study, with 29 eyes in the forme fruste keratoconus (FFKC) group, 34 eyes in the mild KC group, 40 eyes in the moderate KC group, and 46 eyes in the severe KC group. Employing the within-subject standard deviation (Sw), test-retest variability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) to evaluate intraoperator repeatability and interoperator reproducibility. Results: The repeatability and reproducibility of MS-39 in patients with KC were acceptable, according to ICC values ranging from 0.732 to 0.954. However, patients with more severe KC and progressive peripheralization of the measurement points had higher TRTs but a thinning trend. The current study tended to set the cut-off values of mild KC, moderate KC, and severe KC to 4.9 µm, 5.2 µm, and 7.4 µm for thinnest epithelium thickness (TET). When differences between follow-ups are higher than those values, progression of the disease is possible. As for center epithelium thickness (CET), cut-off values for mild KC, moderate KC, and severe KC should be 2.8 µm, 4.4 µm, and 5.3 µm. This might be useful in the follow-up and diagnosis of keratoconus. Conclusions: This study demonstrated that the precision of MS-39 was reduced in measuring more severe KC patients and more peripheral corneal points. In determining disease progression, values should be differentiated between disease-related real changes and measurement inaccuracies. Due to the large difference in ET measured by MS-39 between various stages of disease progression, it is necessary to accurately grade KC patients to avoid errors in KC clinical decision-making.
  •  
26.
  • Shegai, Timur, et al. (författare)
  • Managing light polarization via plasmon-molecule interactions within an asymmetric metal nanoparticle trimer
  • 2008
  • Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 105:43, s. 16448-16453
  • Tidskriftsartikel (refereegranskat)abstract
    • The interaction of light with metal nanoparticles leads to novel phenomena mediated by surface plasmon excitations. In this article we use single molecules to characterize the interaction of surface plasmons with light, and show that such interaction can strongly modulate the polarization of the emitted light. The simplest nanostructures that enable such polarization modulation are asymmetric silver nanocrystal trimers, where individual Raman scattering molecules are located in the gap between two of the nanoparticles. The third particle breaks the dipolar symmetry of the two-particle junction, generating a wavelength-dependent polarization pattern. Indeed, the scattered light becomes elliptically polarized and its intensity pattern is rotated in the presence of the third particle. We use a combination of spectroscopic observations on single molecules, scanning electron microscope imaging, and generalized Mie theory calculations to provide a full picture of the effect of particles on the polarization of the emitted light. Furthermore, our theoretical analysis allows us to show that the observed phenomenon is very sensitive to the size of the trimer particles and their relative position, suggesting future means for precise control of light polarization on the nanoscale.
  •  
27.
  • Topal, Ozan Alp, et al. (författare)
  • Millimeter-Wave Channel Modeling and Coverage Analysis for Indoor Dense Spaces
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Millimeter-wave channel modeling for airplanes, trains, and other in-vehicle environments can be considered jointly as different variations of a general site, namely an indoor dense space (IDS). In this work, by using ray-tracing (RT) simulations, we compare the effect of frame material, user density, and geometry on the channel characteristics at 28, 39, and 60 GHz bands. We observe that temporal and spatial parameters in IDS have unique distributions some depending on the transmitter (TX)-receiver (RX) separation in comparison to the indoor office (IO) channel model. The frame material is the main determining factor of the channel characteristics, with different bands and geometries show minor effects. We extend our channel modeling effort to MIMO deployment analysis to compare the validity of the proposed model in terms of coverage and spectral efficiency with the IO model. Several dominant angular intervals in the channel cause five times higher spectral efficiency gained by digital beamforming (BF) in comparison to analog BF. We observe that the path loss in IDS is more severe compared with IO, resulting in at least a 50% reduction in the coverage area.
  •  
28.
  • Wang, Chunyu, et al. (författare)
  • Co-regulation of temperature and moisture in the irrigated agricultural ecosystem productivity
  • 2023
  • Ingår i: Agricultural Water Management. - : Elsevier BV. - 0378-3774. ; 275
  • Tidskriftsartikel (refereegranskat)abstract
    • Agroecosystem photosynthesis is key to coping with global climate change. In farmland where human activities are highly involved, the interaction between environmental factors and their influences on gross primary productivity (GPP) are insufficiently understood. Particularly, the irrigation and mulching in water-saving agriculture can alter the crop responses to environmental change. Based on eddy covariance measurements of maize fields under mulched drip irrigation (DM) and mulched border irrigation (BM) in arid areas of Northwest China from 2014 to 2018, we systematically studied the interaction between multiple environmental factors and their independent effects on GPP using structural equation modeling, partial correlation coefficient and decoupling analysis by bins. The top three factors exerting the largest total effects on the GPP were soil temperature (Ts), canopy temperature (Tc) and vapor pressure deficit (VPD), among which Ts (0.75) and Tc (0.66) had the largest total effect on GPP under DM and BM, respectively. The independent effects of Ts, soil water content (SWC) and VPD on GPP were different under the two irrigation methods. SWC after excluding the influence of Ts showed a negative effect on GPP under DM (−1.24 g Cm−2d−1), while a positive effect under BM (0.02 g Cm−2d−1). By contrast, SWC after excluding the influence of VPD showed a positive effect on GPP under DM (0.59 g Cm−2d−1), while a negative effect under BM (−0.05 g Cm−2d−1). Interestingly, higher Ts, lower SWC and higher VPD had the potential to increase GPP under the two irrigation methods. We also found that the total effects of irrigation and VPD as well as the indirect effects of environmental factors on GPP should not be ignored. Our study will provide important reference for dealing with the effect of high temperature and drought stress on agro-ecosystem GPP and evaluating the response of vegetation to environmental factors.
  •  
29.
  • Wang, Chunyu, et al. (författare)
  • Water use efficiency control for a maize field under mulched drip irrigation
  • 2023
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 857
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural ecosystem water use efficiency (WUE) is an important indicator reflecting carbon-water coupling, but its control mechanisms in managed fields remain unclear. In order to reveal the influencing factors of WUE in the agricultural field under mulched drip irrigation (DM), we carried out the 8-year continuous observations in a maize field from Northwestern China. The structural equation model, relative importance analysis and principal component analysis were used to quantify the regulation effects of environmental and biological factors on WUE at different time scales, in different growth stages and under different hydrothermal conditions. The results showed that annual WUE varied between 2.18 g C Kg−1 H2O and 3.60 g C Kg−1 H2O, with a multi-year mean of 2.91 g C Kg−1 H2O. The total effects of air temperature on the daily WUE in the whole growth period, the vegetative growth stage, the warm and dry years, the cold and wet years, and the warm and wet years were the largest, with values of 0.61, 0.80, 0.70, 0.70 and 0.91 respectively. However, vapor pressure deficit and net radiation had the largest total effect in the cold and dry years (−0.63) and the reproductive growth stage (−0.49), respectively. Leaf biomass played a leading role in regulating the daily and interannual WUE, and the relative importance of leaf biomass to WUE in the vegetative growth stage was up to 75 %. In the warm and wet years, the relative importance of root biomass to WUE was 33 %, slightly higher than that of leaf biomass (31 %). At the same time, we found that Ta has the potential to increase WUE under future climate warming. Our results improve the understanding of carbon-water coupling mechanisms and provide important enlightenment on how crop ecosystems should adapt to future climate change.
  •  
30.
  • Wang, Wei, et al. (författare)
  • Ag@SiO2 Core-Shell Nanoparticles for Probing Spatial Distribution of Electromagnetic Field Enhancement via Surface-Enhanced Raman Scattering
  • 2009
  • Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 3:11, s. 3493-3496
  • Tidskriftsartikel (refereegranskat)abstract
    • We show that the spatial distribution of the electromagnetic (EM) field enhancement can be probed directly via dynamic evolution of surface-enhanced Raman scattering (SERS) of rhodamine 6G (R6G) molecules as they diffuse into Ag@SiO2 core-shell nanoparticles. The porous silica shell limits the diffusion of R6G molecules toward Inner Ag cores, thereby allowing direct observation and quantification of the spatial distribution of SERS enhancement as molecules migrate from the low to high EM fields inside the dielectric silica shell. Our experimental evidence is validated by the generalized Mie theory, and the approach can potentially offer a novel platform for further investigating the site and spatial distribution of the EM fields and the EM versus chemical enhancement of SERS due to molecular confinement within the Ag@SiO2 nanoshell.
  •  
31.
  • Xia, Zhisheng, et al. (författare)
  • Fabrication and Tribological Properties of Nickel-Based Cellular Structure Self-Lubricating Composites by Selective Laser Melting and Metal Infiltration
  • 2023
  • Ingår i: Tribology Transactions. - 1040-2004 .- 1547-397X. ; 66:4, s. 670-682
  • 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.
  •  
32.
  • Zhang, Pan, et al. (författare)
  • Nanochannel-Based Transport in an Interfacial Memristor Can Emulate the Analog Weight Modulation of Synapses
  • 2019
  • Ingår i: Nano letters (Print). - : AMER CHEMICAL SOC. - 1530-6984 .- 1530-6992. ; 19:7, s. 4279-4286
  • Tidskriftsartikel (refereegranskat)abstract
    • By exploiting novel transport phenomena such as ion selectivity at the nanoscale, it has been shown that nanochannel systems can exhibit electrically controllable conductance, suggesting their potential use in neuromorphic devices. However, several critical features of biological synapses, particularly their conductance modulation, which is both memorable and gradual, have rarely been reported in these types of systems due to the fast flow property of typical inorganic electrolytes. In this work, we demonstrate that electrically manipulating the nanochannel conductance can result in nonvolatile conductance tuning capable of mimicking the analog behavior of synapses by introducing a room-temperature ionic liquid (IL) and a KCl solution into the two ends of a nanochannel system. The gradual conductance-tuning mechanism is identified through fluorescence measurements as the voltage-induced movement of the interface between the immiscible IL and KCl solution, while the successful memorization of the conductance tuning is ascribed to the large viscosity of the IL. We applied a nanochannel-based synapse to a handwritten digit-recognition task, reaching an accuracy of 94%. These promising results provide important guidance for the future design of nanochannel-based neuromorphic devices and the manipulation of nanochannel transport for computing.
  •  
33.
  • Zhang, Shunming, et al. (författare)
  • Adherence to a healthy lifestyle including sleep and sedentary behaviors and risk of metabolic dysfunction-associated steatotic liver disease in Chinese adults
  • 2024
  • Ingår i: Preventive Medicine. - 0091-7435. ; 184
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Various lifestyle factors including smoking, alcohol, physical activity, sedentary behavior, diet quality, sleep behavior, and overweight have been related to metabolic dysfunction-associated steatotic liver disease (MASLD); however, their joint impact on risk of MASLD is not well known. We prospectively investigated the association between a combination of lifestyle factors and risk of MASLD. Methods: This prospective cohort study included 13,303 participants (mean age: 39.1 ± 11.3 years, female: 60.1%) in China. A novel healthy lifestyle score was created combining seven healthy factors: not smoking, no alcohol intake, regular physical activity, short sedentary time, healthy diet, healthy sleep, and healthy weight. Incident MASLD cases were ascertained annually by liver ultrasound and cardiometabolic risk factors. Multivariable Cox proportional hazards regression models were used to estimate the association of healthy lifestyle score with risk of MASLD. Results: Within 48,036 person-years of follow-up, 2823 participants developed MASLD. After adjusting for age, sex, education, occupation, household income, personal and family history of disease, and total energy intake, compared with participants with 0–2 healthy lifestyle factors, the multivariable hazard ratios (95% confidence interval) of MASLD were 0.81 (0.73, 0.89), 0.67 (0.61, 0.75), and 0.55 (0.49, 0.62) for healthy lifestyle score of 3, 4, and 5–7, respectively (P for trend <0.0001). Such associations were consistent across subgroup and sensitivity analyses. Conclusion: Our results indicate that a higher healthy lifestyle score is associated with a lower risk of MASLD.
  •  
34.
  • Zhang, Wenhua, 1981-, et al. (författare)
  • A first-principles study of NO adsorption and oxidation on Au(111) surface
  • 2008
  • Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 129:13, s. 134708-
  • Tidskriftsartikel (refereegranskat)abstract
    • Density functional theory and slab models are employed to study NO molecule adsorption and reaction on clean and atomic oxygen precovered Au(111) surfaces. While clean Au(111) surface is catalytically inert and can only weakly adsorb NO, an atomic oxygen precovered Au(111) surface is found to be very active to NO. On the clean surface, NO prefers to bond at the onefold on-top surface site with a tilted geometry. On 0.33 ML (monolayer) oxygen precovered surface NO reacts with chemisorbed oxygen to form chemisorbed NO2 by conquering a small energy barrier about 0.18 eV, and the desorption energy of NO 2 is 0.64 eV. On 1.0 ML oxygen coverage surface, no barrier is found while NO reacts with precovered oxygen. The desorption energy of NO2 is 0.03 eV. The desorption of NO2 is the rate determining step on both surfaces and the overall reaction barriers are 0.64 and 0.03 eV, respectively. The activation energies depend on the initial coverage of oxygen, which compare favorably with experiments on Au surface with different oxygen coverages.
  •  
35.
  • Zhang, Wenhua, 1981-, et al. (författare)
  • Density Functional Study on the Mechanism of CO Oxidation with Activated Water on O/Au(111) Surface
  • 2009
  • Ingår i: Chinese Science Bulletin. - : Elsevier BV. - 1001-6538 .- 1861-9541 .- 2095-9273 .- 2095-9281. ; 54:11, s. 1973-1977
  • Tidskriftsartikel (refereegranskat)abstract
    • With density functional theory, the mechanism of water-enhanced CO oxidation on oxygen pre-covered Au (111) surface is theoretically studied. First, water is activated by the pre-covered oxygen atom and dissociates to OHads group. Then, OHads reacts with COads to form chemisorbed HOCOads. Finally, with the aid of water, HOCO ads dissociates to CO2. The whole process can be described as 1/2H2O ads + H2Oads + 1/2O ads + COads → H3Oads + CO 2, gas. One CO2 is formed with only 1/2 pre-covered oxygen atom. That is why more CO2 is observed when water is present on oxygen pre-covered Au (111) surface. Activation energy of each elementary step is low enough to allow the reaction to proceed at low temperature
  •  
36.
  • Zhang, Wenhua, et al. (författare)
  • First Principles Study on the Geometric and Electronic Structures of the FeO/Pt(111) Surface
  • 2009
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 113:19, s. 8302-8305
  • Tidskriftsartikel (refereegranskat)abstract
    • The geometric, electronic, and magnetic properties of the FeO monolayer on a Pt(111) surface are investigated by first principles calculations. Generally, antiferromagnetic (AFM) structures are more stable than that of the ferromagnetic one. On the basis of a specific AFM structure, the long puzzling scanning tunneling microscopy (STM) experimental observations can be well explained. In this AFM model, the Fe-O layer distance at the fee region is larger than the hcp region, in contrast to previous theoretical results. The STM images at the field-emission regime are explained by local surface potential.
  •  
37.
  • Zhang, Wenhua, et al. (författare)
  • Oxidation states of graphene : Insights from computational spectroscopy
  • 2009
  • Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 131:24
  • Tidskriftsartikel (refereegranskat)abstract
    • When it is oxidized, graphite can be easily exfoliated forming graphene oxide (GO). GO is a critical intermediate for massive production of graphene, and it is also an important material with various application potentials. With many different oxidation species randomly distributed on the basal plane, GO has a complicated nonstoichiometric atomic structure that is still not well understood in spite of intensive studies involving many experimental techniques. Controversies often exist in experimental data interpretation. We report here a first principles study on binding energy of carbon 1s orbital in GO. The calculated results can be well used to interpret experimental x-ray photoelectron spectroscopy (XPS) data and provide a unified spectral assignment. Based on the first principles understanding of XPS, a GO structure model containing new oxidation species epoxy pair and epoxy-hydroxy pair is proposed. Our results demonstrate that first principles computational spectroscopy provides a powerful means to investigate GO structure.
  •  
38.
  • Zhang, Wenhua, et al. (författare)
  • Theoretical Study of X-ray PhotoemissionSpectra of Graphene Oxide
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Chemical structure of graphene oxide is complicated by the presence of many different oxidation species. We report here a density functional theory study on binding energy of carbon 1s at different oxidation environments on a graphene oxide sheet. It is shown that the calculated results can be wellused to interpret experimental X-ray photoemission spectra of different research groups and provide united spectral assignments. New species that are important for understanding cut mechanisms of graphene oxide have been identified.
  •  
39.
  • Zhao, Juan, et al. (författare)
  • 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
  • Ingår i: BMJ Open. - : BMJ Publishing Group: Open Access / BMJ Journals. - 2044-6055. ; 5:6
  • 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).
  •  
40.
  • Zhu, Zhenyu, et al. (författare)
  • Origin of prestrain-induced cyclic-strain hardening: Multi-scale experimental characterizations and simulations of 7075 aluminum alloy
  • 2024
  • Ingår i: Materials & design. - : ELSEVIER SCI LTD. - 0264-1275 .- 1873-4197. ; 238
  • Tidskriftsartikel (refereegranskat)abstract
    • The influence of prefabricated dislocation features induced by rate dependent prestrain on the post-cyclic process in 7075 aluminum alloy exhibits significant variations, which are of great importance in terms of concerns, designs, and discoveries. Considering strain rate dependent prestrain provides diversified hardening stimuli for the subsequent cyclic process. The maximum cyclic stress in the post-cyclic stage was maintained at the same level as the prestress with strain rates ranging from 10-4s-1 to 10-1s-1. Subsequently, by adjusting post-cycling stress amplitude, research was conducted on quasi-plastic amplitude cycle (QPC) and low plasticity amplitude cycle (LPC) loading conditions. Through experimental mechanism analysis, as well as verification through molecular dynamics and crystal plasticity simulations, prestrain induced by rapid strain rates enhanced the hardening during QPC, stemming from the effects of matrix reconstruction strengthening and wavy structured grain boundaries. However, prestrain induced by slow strain rates promoted the hardening during LPC, primarily arising from the non-uniform crystal structures within individual grains, which was achieved through the complex sub-crystal clusters at grain boundaries, along with intracrystal orderly slipping lattice. These findings offer new insights for the optimization of microstructural design through dislocation engineering.
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