| 1. |
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| 2. |
- 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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| 3. |
- Zhang, Guojie, et al.
(författare)
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Comparative genomics reveals insights into avian genome evolution and adaptation
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1311-1320
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Tidskriftsartikel (refereegranskat)abstract
- Birds are the most species-rich class of tetrapod vertebrates and have wide relevance across many research fields. We explored bird macroevolution using full genomes from 48 avian species representing all major extant clades. The avian genome is principally characterized by its constrained size, which predominantly arose because of lineage-specific erosion of repetitive elements, large segmental deletions, and gene loss. Avian genomes furthermore show a remarkably high degree of evolutionary stasis at the levels of nucleotide sequence, gene synteny, and chromosomal structure. Despite this pattern of conservation, we detected many non-neutral evolutionary changes in protein-coding genes and noncoding regions. These analyses reveal that pan-avian genomic diversity covaries with adaptations to different lifestyles and convergent evolution of traits.
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| 4. |
- Ablikim, M., et al.
(författare)
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Search for h(c) -> pi(+)pi(-) J/psi via psi(3686) -> pi(0)pi(+)pi(-) J/psi
- 2018
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 97:5
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 448.1 x 10(6) psi(3686) events collected with the BESIII detector operating at the BEPCII, we perform search for the hadronic transition h(c)-> pi(+)pi(-) J/psi via psi (3686) -> pi(0)hc. No signals of the transition are observed, and the upper limit on the product branching fraction B(sigma(3686) -> pi(0)h(c))B(h(c) -> pi(+)pi(-) J/psi) at the 90% confidence level (C. L.) is determined to be 2.0 x 10(-6). This is the most stringent upper limit to date.
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| 5. |
- Bhat, Goutam, et al.
(författare)
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NTIRE 2022 Burst Super-Resolution Challenge
- 2022
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Ingår i: 2022 IEEE/CVF CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION WORKSHOPS (CVPRW 2022). - : IEEE. - 9781665487399 - 9781665487405 ; , s. 1040-1060
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Konferensbidrag (refereegranskat)abstract
- Burst super-resolution has received increased attention in recent years due to its applications in mobile photography. By merging information from multiple shifted images of a scene, burst super-resolution aims to recover details which otherwise cannot be obtained using a simple input image. This paper reviews the NTIRE 2022 challenge on burst super-resolution. In the challenge, the participants were tasked with generating a clean RGB image with 4x higher resolution, given a RAW noisy burst as input. That is, the methods need to perform joint denoising, demosaicking, and super-resolution. The challenge consisted of 2 tracks. Track 1 employed synthetic data, where pixel-accurate high-resolution ground truths are available. Track 2 on the other hand used real-world bursts captured from a handheld camera, along with approximately aligned reference images captured using a DSLR. 14 teams participated in the final testing phase. The top performing methods establish a new state-of-the-art on the burst super-resolution task.
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| 6. |
- Chang, Yue, et al.
(författare)
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Cd-Metallothioneins in Three Additional Tetrahymena Species : Intragenic Repeat Patterns and Induction by Metal Ions
- 2014
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Ingår i: Journal of Eukaryotic Microbiology. - : Wiley. - 1066-5234 .- 1550-7408. ; 61:4, s. 333-342
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Tidskriftsartikel (refereegranskat)abstract
- Ciliate metallothioneins (MTs) possess many unique features compared to the "classic" MTs in other organisms, but they have only been studied in a small number of species. In this study, we investigated cDNAs encoding subfamily 7a metallothioneins (CdMTs) in three Tetrahymena species (T. hegewischi, T. malaccensis, and T. mobilis). Four CdMT genes (ThegMT1, ThegMT2, TmalMT1, and TmobMT1) were cloned and characterized. They share high sequence similarity to previously identified subfamily 7a MT members. Tetrahymena CdMTs exhibit a remarkably regular intragenic repeat homology. The CdMT sequences were divided into two main types of modules, which had been previously described, and which we name "A" and "B". ThegMT2 was identified as the first MT isoform solely composed of module "B". A phylogenetic analysis of individual modules of every characterized Tetrahymena CdMT rigorously documents the conclusion that modules are important units of CdMT evolution, which have undergone frequent and rapid gain/loss and shuffling. The transcriptional activity of the four newly identified genes was measured under different heavy metal exposure (Cd, Cu, Zn, Pb) using real-time quantitative PCR. The results showed that these genes were differentially induced after short (1 h) or long (24 h) metal exposure. The evolutionary diversity of Tetrahymena CdMTs is further discussed with regard to their induction by metal ions.
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| 7. |
- Corander, Jukka, et al.
(författare)
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Optimal Viterbi Bayesian predictive classification for data from finite alphabets
- 2013
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Ingår i: Journal of Statistical Planning and Inference. - : Elsevier BV. - 0378-3758 .- 1873-1171. ; 143:2, s. 261-275
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Tidskriftsartikel (refereegranskat)abstract
- A family of Viterbi Bayesian predictive classifiers has been recently popularized for speech recognition applications with continuous acoustic signals modeled by finite mixture densities embedded in a hidden Markov framework. Here we generalize such classifiers to sequentially observed data from multiple finite alphabets and derive the optimal predictive classifier under exchangeability of the emitted symbols. We demonstrate that the optimal predictive classifier which learns from unlabelled test items improves considerably upon marginal maximum a posteriori rule in the presence of sparse training data. It is shown that the learning process saturates when the amount of test data tends to infinity, such that no further gain in classification accuracy is possible upon arrival of new test items in the long run.
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| 8. |
- Dong, Y. B., et al.
(författare)
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Transfer-free, lithography-free, and micrometer-precision patterning of CVD graphene on SiO 2 toward all-carbon electronics
- 2018
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Ingår i: APL Materials. - : AIP Publishing. - 2166-532X. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- A method of producing large area continuous graphene directly on SiO 2 by chemical vapor deposition is systematically developed. Cu thin film catalysts are sputtered onto the SiO 2 and pre-patterned. During graphene deposition, high temperature induces evaporation and balling of the Cu, and the graphene "lands onto" SiO 2 . Due to the high heating and growth rate, continuous graphene is largely completed before the Cu evaporation and balling. 60 nm is identified as the optimal thickness of the Cu for a successful graphene growth and μm-large feature size in the graphene. An all-carbon device is demonstrated based on this technique.
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| 9. |
- Dong, Yibo, et al.
(författare)
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In Situ Growth of CVD Graphene Directly on Dielectric Surface toward Application
- 2020
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Ingår i: ACS Applied Electronic Materials. - : American Chemical Society (ACS). - 2637-6113. ; 2:1, s. 238-246
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Tidskriftsartikel (refereegranskat)abstract
- A technique for the in situ growth of patterned graphene by CVD has been achieved directly on insulating substrates at 800 degrees C. The graphene growth is catalyzed by a Ni-Cu alloy sacrificial layer, which integrates many advantages such as being lithography-free, and almost wrinkle-free, with a high repeatability and rapid growth. The etching method of the metal sacrificial layer is the core of this technique, and the mechanism is analyzed. Graphene has been found to play an important role in accelerating etching speeds. The Ni-Cu alloy exhibits a high catalytic activity, and thus, high-quality graphene can be obtained at a lower temperature. Moreover, the Ni-Cu layer accommodates a limited amount of carbon atoms, which ensures a high monolayer ratio of the graphene. The carbon solid solubility of the alloy is calculated theoretically and used to explain the experimental findings. The method is compatible with the current semiconductor process and is conducive to the industrialization of graphene devices.
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| 10. |
- Dong, Yibo, et al.
(författare)
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Transfer-free, lithography-free and fast growth of patterned CVD graphene directly on insulators by using sacrificial metal catalyst
- 2018
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Ingår i: Nanotechnology. - : IOP Publishing. - 1361-6528 .- 0957-4484. ; 29:36
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Tidskriftsartikel (refereegranskat)abstract
- Chemical vapor deposited graphene suffers from two problems: transfer from metal catalysts to insulators, and photoresist induced degradation during patterning. Both result in macroscopic and microscopic damages such as holes, tears, doping, and contamination, translated into property and yield dropping. We attempt to solve the problems simultaneously. A nickel thin film is evaporated on SiO2 as a sacrificial catalyst, on which surface graphene is grown. A polymer (PMMA) support is spin-coated on the graphene. During the Ni wet etching process, the etchant can permeate the polymer, making the etching efficient. The PMMA/graphene layer is fixed on the substrate by controlling the surface morphology of Ni film during the graphene growth. After etching, the graphene naturally adheres to the insulating substrate. By using this method, transfer-free, lithography-free and fast growth of graphene realized. The whole experiment has good repeatability and controllability. Compared with graphene transfer between substrates, here, no mechanical manipulation is required, leading to minimal damage. Due to the presence of Ni, the graphene quality is intrinsically better than catalyst-free growth. The Ni thickness and growth temperature are controlled to limit the number of layers of graphene. The technology can be extended to grow other two-dimensional materials with other catalysts.
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| 11. |
- Duan, Chen, et al.
(författare)
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Comparative analysis of gene expression profiles between primary knee osteoarthritis and an osteoarthritis endemic to Northwestern China, Kashin-Beck disease.
- 2010
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Ingår i: Arthritis and Rheumatism. - : John Wiley & Sons. - 0004-3591 .- 1529-0131. ; 62:3, s. 771-780
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the differences in gene expression profiles of adult articular cartilage from patients with Kashin-Beck disease (KBD) versus those with primary knee osteoarthritis (OA).METHODS: The messenger RNA expression profiles of articular cartilage from patients with KBD, diagnosed according to the clinical criteria for KBD in China, were compared with those of cartilage from patients with OA, diagnosed according to the Western Ontario and McMaster Universities OA Index. Total RNA was isolated separately from 4 pairs of the KBD and OA cartilage samples, and the expression profiles were evaluated by Agilent 4x44k Whole Human Genome density oligonucleotide microarray analysis. The microarray data for selected transcripts were confirmed by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) amplification.RESULTS: For 1.2 x 10(4) transcripts, corresponding to 58.4% of the expressed transcripts, 2-fold changes in differential expression were revealed. Expression levels higher in KBD than in OA samples were observed in a mean + or - SD 6,439 + or - 1,041 (14.6 + or - 2.4%) of the transcripts, and expression levels were lower in KBD than in OA samples in 6,147 + or - 1,222 (14.2 + or - 2.8%) of the transcripts. After application of the selection criteria, 1.85% of the differentially expressed genes (P < 0.001 between groups) were detected. These included 233 genes, of which 195 (0.4%) were expressed at higher levels and 38 (0.08%) were expressed at lower levels in KBD than in OA cartilage. Comparisons of the quantitative RT-PCR data supported the validity of our microarray data.CONCLUSION: Differences between KBD and OA cartilage exhibited a similar pattern among all 4 of the pairs examined, indicating the presence of disease mechanisms, mainly chondrocyte matrix metabolism, cartilage degeneration, and apoptosis induction pathways, which contribute to cartilage destruction in KBD.
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| 12. |
- Geng, H., et al.
(författare)
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Incomplete B cell tolerance to cartilage oligomeric matrix protein in mice
- 2013
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 65:9, s. 2301-2309
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Cartilage oligomeric matrix protein (COMP) is a major noncollagenous component of cartilage and is used as a biomarker in rheumatoid arthritis and experimental arthritis. Injection of COMP leads to severe inflammatory joint disease, and antibodies play a critical role in mediating arthritis. The arthritogenicity of COMP might be due to the lack of self tolerance. This study was undertaken to determine the status of COMP-specific B cell tolerance using COMP-deficient mice. METHODS: Arthritis development and antibody responses were compared between COMP-sufficient and COMP-deficient littermates after immunization with rat COMP. Serum anti-COMP antibody levels were measured using a panel of recombinant mouse COMP proteins, and antibody-secreting cells were enumerated by enzyme-linked immunospot assays. A novel sandwich enzyme-linked immunosorbent assay was developed to assess COMP molecules in serum. RESULTS: COMP-sufficient mice, but not COMP-deficient mice, developed severe arthritis following immunization with rat COMP. However, anti-COMP antibody titers to native COMP and recombinant protein domains covering the entire mouse COMP sequence, except the less immunodominant type 3 repeat domains, were decreased in COMP-sufficient mice compared to COMP-deficient mice. In addition, COMP-sufficient mice had fewer B cells secreting COMP-reactive antibodies. Detectable levels of full-length COMP in arthritic COMP-sufficient B10.Q NCF-1(*/*) and healthy mice suggested systemic availability of COMP to the immune system. CONCLUSION: The lack of arthritis, together with high levels of COMP-specific antibodies, in COMP-deficient mice indicates that susceptibility to arthritis is COMP specific and that endogenous expression of COMP in wild-type mice tolerizes B cells in vivo.
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| 13. |
- Haghighi, Mona, et al.
(författare)
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A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
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| 14. |
- He, Shu-Lan, et al.
(författare)
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Mitochondrial-related gene expression profiles suggest an important role of PGC-1alpha in the compensatory mechanism of endemic dilated cardiomyopathy.
- 2013
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Ingår i: Experimental Cell Research. - : Elsevier. - 0014-4827 .- 1090-2422. ; 319:17, s. 2604-2616
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Tidskriftsartikel (refereegranskat)abstract
- Keshan disease (KD) is an endemic dilated cardiomyopathy with unclear etiology. In this study, we compared mitochondrial-related gene expression profiles of peripheral blood mononuclear cells (PBMCs) derived from 16 KD patients and 16 normal controls in KD areas. Total RNA was isolated, amplified, labeled and hybridized to Agilent human 4 × 44k whole genome microarrays. Mitochondrial-related genes were screened out by the Third-Generation Human Mitochondria-Focused cDNA Microarray (hMitChip3). Quantitative real-time PCR, immunohistochemical and biochemical parameters related mitochondrial metabolism were conducted to validate our microarray results. In KD samples, 34 up-regulated genes (ratios ≥ 2.0) were detected by significance analysis of microarrays and ingenuity systems pathway analysis (IPA). The highest ranked molecular and cellular functions of the differentially regulated genes were closely related to amino acid metabolism, free radical scavenging, carbohydrate metabolism, and energy production. Using IPA, 40 significant pathways and four significant networks, involved mainly in apoptosis, mitochondrion dysfunction, and nuclear receptor signaling were identified. Based on our results, we suggest that PGC-1alpha regulated energy metabolism and anti-apoptosis might play an important role in the compensatory mechanism of KD. Our results may lead to the identification of potential diagnostic biomarkers for KD in PBMCs, and may help to understand the pathogenesis of KD.
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| 15. |
- Jääskinen, Väinö, et al.
(författare)
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Sparse Markov Chains for Sequence Data. Scandinavian Journal of Statistics
- 2014
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Ingår i: Scandinavian Journal of Statistics. - New York : John Wiley & Sons, Inc.. - 0303-6898 .- 1467-9469. ; 41:3, s. 639-655
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Tidskriftsartikel (refereegranskat)abstract
- Finite memory sources and variable-length Markov chains have recently gained popularity in data compression and mining, in particular, for applications in bioinformatics and language modelling. Here, we consider denser data compression and prediction with a family of sparse Bayesian predictive models for Markov chains in finite state spaces. Our approach lumps transition probabilities into classes composed of invariant probabilities, such that the resulting models need not have a hierarchical structure as in context tree-based approaches. This can lead to a substantially higher rate of data compression, and such non-hierarchical sparse models can be motivated for instance by data dependence structures existing in the bioinformatics context. We describe a Bayesian inference algorithm for learning sparse Markov models through clustering of transition probabilities. Experiments with DNA sequence and protein data show that our approach is competitive in both prediction and classification when compared with several alternative methods on the basis of variable memory length.
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| 16. |
- Lin, Hao, et al.
(författare)
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Stable and efficient hybrid Ag-In-S/ZnS@SiO2-carbon quantum dots nanocomposites for white light-emitting diodes
- 2020
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 393
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Tidskriftsartikel (refereegranskat)abstract
- As a promising energy-saving technique, the eco-friendly and low-cost solid-state white light-emitting diodes (WLEDs) based on quantum dots (QDs) have been widely studied. Herein, a WLED device prepared by core-shell structure nanocomposites based on Ag-In-S/ZnS@SiO2 quantum dots (AIS@SiO2) and carbon quantum dots (CDs) was successfully constructed. CDs were combined onto the surface of AIS@SiO2 QDs to synthesize Ag-In-S/ZnS@SiO2-Carbon quantum dots (AIS-CDs) nanocomposites with a white-light emission, which successfully overcome the quenching effect of CDs induced by conventional aggregation. The as-prepared AIS-CDs nanocomposites presented high stability and a photoluminescence quantum yield (PLQY) of 35%. Moreover, the corresponding AIS-CDs nanocomposites-based WLEDs demonstrated the color coordinate of (0.32, 0.33), which is comparable to the pure white light (0.33, 0.33); furthermore, the luminous efficiency of the as-prepared WLEDs showed 15.1 lm W-1. These results reported herein may open up a new avenue for the development of high-performance, low-cost, and environmentally-friendly WLEDs.
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| 17. |
- Lu, Chunyang, et al.
(författare)
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Life cycle assessment of carbonaceous pellets used in blast furnaces in the context of “double carbon”
- 2024
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Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 935
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Tidskriftsartikel (refereegranskat)abstract
- As the sole carbonaceous renewable energy source, biomass is distinguished by its abundant yield, widespread distribution, and carbon neutrality. It is integral to the achievement of zero and negative carbon production via conventional carbonaceous pellet technology. This study introduces a cradle-to-gate life cycle assessment methodology for biomass preparation in carbonaceous pellets. We prepare high-quality biochar through a process combining hydrothermal carbonization and pyrolytic carbonization. Biomass high molecular weight extracts are obtained via organic pyrolytic extraction, while biomass high-temperature binders result from the modification and treatment of biochar. Biomass carbonaceous pellets are then formed using hot press technology. The ReCiPe model facilitates a comprehensive life cycle assessment of biomass carbonaceous pellets used in blast furnace production. The study leverages two comprehensive evaluation indicators - renewability, and environmental performance - to enhance the environmental performance of the process system and to maximize energy-saving and emission reduction potential.
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| 18. |
- Mao, Sun, et al.
(författare)
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Intelligent Reflecting Surface-Aided Wireless Powered Hybrid Backscatter-Active Communication Networks
- 2023
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Ingår i: IEEE Transactions on Vehicular Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9545 .- 1939-9359. ; 72:1, s. 1383-1388
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Tidskriftsartikel (refereegranskat)abstract
- Wireless powered hybrid backscatter-active communications are recognized as the promising technique to provide the sustainable communication service for wireless devices. In this paper, we consider an intelligent reflecting surface-aided wireless powered hybrid backscatter-active communication network, where multiple sensors devices powered by a power beacon, transmit their information to an access point through backscatter and active communications. In particular, an intelligent reflecting surface is properly deployed to improve the communication quality between sensor devices and access point by utilizing the composite channel gain and phase beamforming gain. Furthermore, we formulate a system energy efficiency maximization problem under the minimum throughput requirements of sensor devices, to jointly optimize the phase shifts of intelligent reflecting surface, time allocation for backscatter communications and active transmissions, and transmit power of sensor devices and power beacon. To solve the formulated non-convex problem, we first unveil the optimal phase shifts of intelligent reflecting surface, and then utilize the variable substitutions and Dinkelbach-based method to develop an iterative method to solve the energy efficiency maximization problem. Simulation results reveal that the proposed method outperforms the existing several benchmark methods in terms of system energy efficiency.
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| 19. |
- Pecunia, Vincenzo, et al.
(författare)
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Roadmap on energy harvesting materials
- 2023
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Ingår i: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.
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| 20. |
- Qiu, Yuanlin, et al.
(författare)
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Lake-Area Expansion Alters Downwind Precipitation Patterns on the Tibetan Plateau: Insights From the Most Dramatically Expanded Lake
- 2023
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Ingår i: Journal of Geophysical Research: Atmospheres. - 2169-897X .- 2169-8996. ; 128:15
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Tidskriftsartikel (refereegranskat)abstract
- A large portion of lakes on the Tibetan Plateau (TP) have experienced considerable expansion in the past decades. However, how the lake surface area expansion has influenced regional precipitation, especially its underlying mechanism, has not been investigated. By selecting the most dramatically expanded lake on the TP as a case study, this paper investigates the magnitude and extent of the precipitation response to lake expansion and its underlying mechanism using twin Weather Research and Forecasting (WRF) simulations with and without lake expansion. The results show that the precipitation response to the lake expansion exhibits pronounced spatial and seasonal variations and is generally more intense in the downwind direction than in the upwind direction. During the wet season (the South Asian summer monsoon, SASM), precipitation decreases in the downwind area by −25%±16% and −13%±15% in the 0–50km and 50–100km intervals (from the lake’s center), respectively. Conversely, the precipitation increases in the downwind area during the dry season (before the freeze and after the SASM) by 27%±36% in the 0–50km interval. The thermal and evaporative effects, which are generated by lake expansion and propagate in the downwind direction, are the key factors responsible for the precipitation changes. The cooling effect, which generally occurs in the daytime, stabilizes the atmosphere and triggers downward motion, consequently inhibiting precipitation. The warming effect has the opposite effect, and the additional water vapor strengthens this process. However, the effects vary with the seasons, causing seasonal variations in the precipitation response.
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| 21. |
- Sun, Jie, 1977, et al.
(författare)
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Insights into the Mechanism for Vertical Graphene Growth by Plasma-Enhanced Chemical Vapor Deposition
- 2022
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Ingår i: Acs Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 14:5, s. 7152-7160
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Tidskriftsartikel (refereegranskat)abstract
- Vertically oriented graphene (VG) has attracted attention for years, but the growth mechanism is still not fully revealed. The electric field may play a role, but the direct evidence and exactly what role it plays remains unclear. Here, we conduct a systematic study and find that in plasma-enhanced chemical vapor deposition, the VG growth preferably occurs at spots where the local field is stronger, for example, at GaN nanowire tips. On almost round-shaped nanoparticles, instead of being perpendicular to the substrate, the VG grows along the field direction, that is, perpendicular to the particles' local surfaces. Even more convincingly, the sheath field is screened to different degrees, and a direct correlation between the field strength and the VG growth is observed. Numerical calculation suggests that during the growth, the field helps accumulate charges on graphene, which eventually changes the cohesive graphene layers into separate three-dimensional VG flakes. Furthermore, the field helps attract charged precursors to places sticking out from the substrate and makes them even sharper and turn into VG. Finally, we demonstrate that the VG-covered nanoparticles are benign to human blood leukocytes and could be considered for drug delivery. Our research may serve as a starting point for further vertical two-dimensional material growth mechanism studies.
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| 22. |
- Tang, Peng Hao, et al.
(författare)
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A patterning technology of transfer-free graphene for transparent electrodes of near-ultraviolet light-emitting diodes
- 2024
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Ingår i: Journal of Materials Chemistry C. - 2050-7534 .- 2050-7526. ; 12:26, s. 9824-9833
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Tidskriftsartikel (refereegranskat)abstract
- Graphene is well known for its excellent physical and chemical properties and can be used in various fields. Its application technology has become an important direction of research. In this study, a patterning technology of transfer-free graphene is reported, and graphene transparent electrodes of near-ultraviolet light-emitting diodes (LEDs) are fabricated accordingly. In the scheme, Ni film plays the dual role of an etching mask and graphene growth catalyst, realizing the patterning growth of graphene. An SiO2 isolation layer is deposited between Ni and the substrate, avoiding the fusing of the substrate with Ni by the high temperature of graphene growth, which makes the method applicable to nominally any high temperature-compatible metal and semiconductor substrates. Both Ni and SiO2 are then removed, thus directly achieving a good contact between graphene and the substrate. The graphene transparent electrodes fabricated by this method greatly improves the performance of near-ultraviolet LEDs, which is even better than that of indium tin oxide (ITO) in the near-ultraviolet band based on the optical measurement results. This scheme avoids any possible damage and contamination of graphene in traditional transfer and lithography patterning processes, which is scalable and suitable for real applications.
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| 23. |
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| 24. |
- Xiong, Fangzhu, et al.
(författare)
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Transfer-free graphene-like thin films on GaN LED epiwafers grown by PECVD using an ultrathin Pt catalyst for transparent electrode applications
- 2019
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 12:21, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we grew transfer-free graphene-like thin films (GLTFs) directly on gallium nitride (GaN)/sapphire light-emitting diode (LED) substrates. Their electrical, optical and thermal properties were studied for transparent electrode applications. Ultrathin platinum (2 nm) was used as the catalyst in the plasma-enhanced chemical vapor deposition (PECVD). The growth parameters were adjusted such that the high temperature exposure of GaN wafers was reduced to its minimum (deposition temperature as low as 600 °C) to ensure the intactness of GaN epilayers. In a comparison study of the Pt-GLTF GaN LED devices and Pt-only LED devices, the former was found to be superior in most aspects, including surface sheet resistance, power consumption, and temperature distribution, but not in optical transmission. This confirmed that the as-developed GLTF-based transparent electrodes had good current spreading, current injection and thermal spreading functionalities. Most importantly, the technique presented herein does not involve any material transfer, rendering a scalable, controllable, reproducible and semiconductor industry-compatible solution for transparent electrodes in GaN-based optoelectronic devices.
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| 25. |
- Xiong, Fangzhu, et al.
(författare)
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Transfer-free rapid growth of 2-inch wafer-scale patterned graphene as transparent conductive electrodes and heat spreaders for GaN LEDs
- 2023
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Ingår i: npj 2D Materials and Applications. - 2397-7132. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- A technique for the transfer-free growth of 2-inch wafer-scale patterned graphene directly on GaN LED epilayers is introduced. High-quality graphene as transparent electrodes and heat spreaders is synthesized directly on GaN by PECVD at only 600 °C deposition temperature and within 3 min growth time. Co acts as both the catalyst for graphene growth and the dry etching mask for GaN mesas, which greatly improves the efficiency of the semiconductor device process. Elegantly, the graphene growth is in accordance with the shape of Co, which offers a lithography-free patterning technique of the graphene. Afterward, using our penetration etching method through the PMMA and graphene layers, the Co is peacefully removed, and in-situ Ohmic contact is achieved between the graphene and p-GaN where the contact resistivity is only 0.421 Ω cm2. The graphene sheet resistance is as low as 631.2 Ω sq−1. The device is also superior to the counterpart graphene-free LED in terms of heat spreading behavior, as evidenced by the lower junction temperature and thermal resistance. Most importantly, the developed technique produces graphene with excellent performance and is intrinsically more scalable, controllable, and semiconductor industry compatible than traditionally transferred graphene.
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| 26. |
- Xiong, Jie, et al.
(författare)
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Genome-wide identification and evolution of ATP-binding cassette transporters in the ciliate Tetrahymena thermophila : A case of functional divergence in a multigene family
- 2010
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 10:1, s. 330-
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Tidskriftsartikel (refereegranskat)abstract
- Background. In eukaryotes, ABC transporters that utilize the energy of ATP hydrolysis to expel cellular substrates into the environment are responsible for most of the efflux from cells. Many members of the superfamily of ABC transporters have been linked with resistance to multiple drugs or toxins. Owing to their medical and toxicological importance, members of the ABC superfamily have been studied in several model organisms and warrant examination in newly sequenced genomes. Results. A total of 165 ABC transporter genes, constituting a highly expanded superfamily relative to its size in other eukaryotes, were identified in the macronuclear genome of the ciliate Tetrahymena thermophila. Based on ortholog comparisons, phylogenetic topologies and intron characterizations, each highly expanded ABC transporter family of T. thermophila was classified into several distinct groups, and hypotheses about their evolutionary relationships are presented. A comprehensive microarray analysis revealed divergent expression patterns among the members of the ABC transporter superfamily during different states of physiology and development. Many of the relatively recently formed duplicate pairs within individual ABC transporter families exhibit significantly different expression patterns. Further analysis showed that multiple mechanisms have led to functional divergence that is responsible for the preservation of duplicated genes. Conclusion. Gene duplications have resulted in an extensive expansion of the superfamily of ABC transporters in the Tetrahymena genome, making it the largest example of its kind reported in any organism to date. Multiple independent duplications and subsequent divergence contributed to the formation of different families of ABC transporter genes. Many of the members within a gene family exhibit different expression patterns. The combination of gene duplication followed by both sequence divergence and acquisition of new patterns of expression likely plays a role in the adaptation of Tetrahymen a to its environment.
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| 27. |
- Yuan, Shuai, et al.
(författare)
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Deciphering the genetic architecture of atrial fibrillation offers insights into disease prediction, pathophysiology and downstream sequelae.
- 2023
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Ingår i: medRxiv : the preprint server for health sciences.
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The study aimed to discover novel genetic loci for atrial fibrillation (AF), explore the shared genetic etiologies between AF and other cardiovascular and cardiometabolic traits, and uncover AF pathogenesis using Mendelian randomization analysis.METHODS AND RESULTS: We conducted a genome-wide association study meta-analysis including 109,787 AF cases and 1,165,920 controls of European ancestry and identified 215 loci, among which 91 were novel. We performed Genomic Structural Equation Modeling analysis between AF and four cardiovascular comorbidities (coronary artery disease, ischemic stroke, heart failure, and vneous thromboembolism) and found 189 loci shared across these diseases as well as a universal genetic locus shared by atherosclerotic outcomes (i.e., rs1537373 near CDKN2B). Three genetic loci (rs10740129 near JMJD1C, rs2370982 near NRXN3, and rs9931494 near FTO) were associated with AF and cardiometabolic traits. A polygenic risk score derived from this genome-wide meta-analysis was associated with AF risk (odds ratio 2.36, 95% confidence interval 2.31-2.41 per standard deviation increase) in the UK biobank. This score, combined with age, sex, and basic clinical features, predicted AF risk (AUC 0.784, 95% CI 0.781-0.787) in Europeans. Phenome-wide association analysis of the polygenic risk score identified many AF-related comorbidities of the circulatory, endocrine, and respiratory systems. Phenome-wide and multi-omic Mendelian randomization analyses identified associations of blood lipids and pressure, diabetes, insomnia, obesity, short sleep, and smoking, 27 blood proteins, one gut microbe (genus.Catenibacterium), and 11 blood metabolites with risk to AF.CONCLUSIONS: This genome-wide association study and trans-omic Mendelian randomization analysis provides insights into disease risk prediction, pathophysiology and downstream sequelae.
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| 28. |
- Zhang, Jie, et al.
(författare)
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A novel vented tunnel hood with decreasing open ratio to mitigate micro-pressure wave emitted at high-speed maglev tunnel exit
- 2023
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Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - 0167-6105. ; 240
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Tidskriftsartikel (refereegranskat)abstract
- The significant increase in train speed contributes to stronger vehicle/tunnel coupling aerodynamic effect, especially on the intensity of the micro-pressure wave (MPW) emitted at high-speed maglev tunnel exit. Hence when the train speed reaches 600 km/h and more, how to effectively mitigate the MPW becomes a challenge for aerodynamic researchers. In this study, a novel vented tunnel hood with the decreasing open ratio along the enlarged cross-section wall was proposed, while one consistent and two inconsistent layouts of the hoods applied at the tunnel portals were attempted to obtain a better hood combination for the mitigation of MPW. In addition, the sliding mesh technique was used to simulate the train passing through the single-track high-speed maglev tunnel. The validation of the methodology has been carried out to compare with the previous moving model test results. The peak variations of pressure wave and MPW were analysed in combination with the grid-independence study and numerical validation. The new hoods installed consistently at the tunnel portals (entrance and exit), can reduce the maximums of MPWs at required locations, i.e., 20m and 50m from the tunnel exit, by 66.9% and 40.9% respectively, when compared to the existing unvented tunnel hood; however, when the new hood at the tunnel exit is replaced by the existing tunnel hood without vents, the maximums of MPWs at the corresponding 20m and 50m are significantly increased by 79.1% and 71.0%. After changing the set-up of the inconsistent hoods, i.e., the tunnel entrance hood is unvented and this novel hood is installed at the tunnel exit, the corresponding MPW peaks can be reduced by 84.0% and 71.1%. Therefore, the hoods at both of tunnel entrance and exit can affect the variations of MPWs, and a reasonable arrangement of the hood openings at tunnel portals can effectively mitigate the MPW emitted at the high-speed maglev tunnel exit.
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| 29. |
- Zhang, Jie, 1987, et al.
(författare)
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A study of the influence of bogie cut outs' angles on the aerodynamic performance of a high-speed train
- 2018
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Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 175, s. 153-168
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Tidskriftsartikel (refereegranskat)abstract
- The aerodynamic drag of a high-speed train can contribute significantly to its energy consumption. Hence, the purpose of this paper is to find out a new compound mode of bogie cut outs to achieve drag reduction for a Chinese high-speed train. In this paper, a Detached Eddy Simulation method based on the Realizable k-ε turbulence model was used to investigate the underbody flow features of high-speed trains with different compound modes in the angles of bogie cut outs at Re = 1.85 × 10 6 . The time-averaged aerodynamic drag was compared with experimental data from wind tunnel tests. The results show that the DES simulations present high accuracy in predicting this kind of flow underneath the train body, and those numerical results closely agree with the experimental data. The variations of bogie cut outs' angles only cause the changes of flow structures around the bogies and in the wake. As a result, obtain different aerodynamic drag forces. Most of drag of the train is experienced by the streamlined head and all bogie regions. A new compound mode of bogie cut outs is proposed in the present paper, achieving 2.92% drag reduction for a three-car model.
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| 30. |
- Zhang, Jie, 1987, et al.
(författare)
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Detached eddy simulation of flow characteristics around railway embankments and the layout of anemometers
- 2019
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Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 193
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Tidskriftsartikel (refereegranskat)abstract
- Anemometers are usually set up along railway embankments to monitor wind speeds, and the layout for them has to be investigated. This work used an improved delayed detached eddy simulation (IDDES) approach to explore the flow properties around railway embankments, and then a proposal was put forward for the layout of anemometers. The numerical method was validated against previous wind tunnel tests on the speed-up ratios of the flow around a 1/300 scale two-dimensional embankment with the slope gradient of 1:2. The effects of inlet velocity profiles, i.e., uniform velocity and atmospheric boundary layer velocity profiles, on the speed-up ratios around a 5 m high railway embankment were compared. The study indicates that using a uniform velocity profile to assess the operational safety of trains running across strong wind regions could be favourable, especially when complex local terrains contribute to different wind characteristics. The anemometers should be set upstream, i.e., at a well defined distance in locations with sufficient extent of open ground and on the electrification masts along railway lines. This is not in line with the anemometer layout of the existing SWEWS (Strong Wind Early Warning Systems), the difference being due to the speed-up effect of the railway embankment, which is usually not considered explicitly. Formulas have been developed on the basis of regression of the simulation results to express the relationships between e.g. top wind speed over the embankment (located in an area where it is not possible to install anemometers) and measured wind speeds. In this way it is possible to take into account the speed-up effect encountered by the wind passing over the embankment, which needs to be considered in the operational rules in order to ensure safe operations.
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| 31. |
- Zhao, Wang, et al.
(författare)
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Non-data-aided timing acquisition for asynchronous IDMA systems
- 2013
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Ingår i: Wireless personal communications. - : Springer Science+Business Media B.V.. - 0929-6212 .- 1572-834X. ; 69:2, s. 957-978
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Tidskriftsartikel (refereegranskat)abstract
- Sample-timing error can cause significant performance degradation for the interleave-division multiple-access systems (Wang et al.2009). In this paper, we propose a nondata-aided timing acquisition scheme tomitigate sample-timing error due to the asynchronoustransmission of random allocated user ends (UEs) on the uplink.Aclosed-loop timing control scheme is constructed for the asynchronous IDMA system in this paper.We use the extrinsic information generated during the iterative detection algorithm with signal noise ratio volution to estimate the timing offset for the asynchronous uplink in the base station (BS) receiver. The BS receiver returns the timing control bits, which is generated with estimated timing offsets, to the corresponding UE. And the UE uses the timing control bits to adjust local transmission time to guarantee the sampling performance at the BS receiver. The simulation results show that the proposed acquisition scheme based on feedback loop can provide high acquisition probability and low false alarm probability. The proposed scheme can overcome the bit-error-rate performance bottleneck, which is caused by the sample-timing error in BS receiver due to the asynchronous signals in the uplink.
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| 32. |
- Zhu, Yan-He, et al.
(författare)
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Efficacy of long-term selenium supplementation in the treatment of chronic Keshan disease with congestive heart failure
- 2019
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Ingår i: Current medical science. - : Springer. - 2096-5230 .- 2523-899X. ; 39:2, s. 237-242
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Tidskriftsartikel (refereegranskat)abstract
- Few effective treatments for chronic Keshan disease have been available till now. The efficacy of long-term selenium supplementation in the treatment of chronic Keshan disease with congestive heart failure is inconclusive. This study aimed to determine whether selenium supplementation is associated with a decreased risk of cardiac death in chronic Keshan disease with congestive heart failure by ten years of follow-up. A retrospective long-term follow-up analysis was performed on a monitored cohort consisting of 302 chronic Keshan disease patients with a mean age of 40.8±11.4 years. Of the 302 chronic Keshan disease patients, 170 (56.3%) were given selenium supplementation until the end point of follow-up. Cox proportional hazards regression models were used to identify the independent predictors of cardiac events. Our results showed that during the follow-up, there were 101 deaths of patients with chronic Keshan disease in the selenium supplementation group (101/170, 59.4%) and 98 in non-selenium supplementation group (98/132, 74.2%). Multivariate analyses suggested that selenium supplementation was associated with a decreased risk of cardiac death (HR 0.39, 95% CI 0.28-0.53) after adjustment for baseline age, sex, cigarette smoking, family history of Keshan disease, body mass index (BMI), heart rate, electrocardiogram (ECG) abnormalities, blood pressure, initial cardiothoracic ratio, left ventricular ejection fractions (LVEF) and whole-blood selenium concentration. Our ten-year follow-up analysis indicated that selenium supplementation, specifically combined with the use of angiotensin-converting enzyme inhibitor and beta blocker therapy, improved the survival of patients with chronic Keshan disease with congestive heart failure. BMI, selenium deficiency, male, combined ECG abnormalities, LVEF, and fast heart rate increased the risk of cardiac events.
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| 33. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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