| 1. |
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| 2. |
- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Deng, Min, et al.
(author)
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Genome-wide association analyses in Han Chinese identify two new susceptibility loci for amyotrophic lateral sclerosis
- 2013
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In: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 45:6, s. 697-
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Journal article (peer-reviewed)abstract
- To identify susceptibility genes for amyotrophic lateral sclerosis (ALS), we conducted a genome-wide association study (GWAS) in 506 individuals with sporadic ALS and 1,859 controls of Han Chinese ancestry. Ninety top SNPs suggested by the current GWAS and 6 SNPs identified by previous GWAS were analyzed in an independent cohort of 706 individuals with ALS and 1,777 controls of Han Chinese ancestry. We discovered two new susceptibility loci for ALS at 1q32 (CAMK1G, rs6703183, P-combined = 2.92 x 10(-8), odds ratio (OR) = 1.31) and 22p11 (CABIN1 and SUSD2, rs8141797, P-combined = 2.35 x 10(-9), OR = 1.52). These two loci explain 12.48% of the overall variance in disease risk in the Han Chinese population. We found no association evidence for the previously reported loci in the Han Chinese population, suggesting genetic heterogeneity of disease susceptibility for ALS between ancestry groups. Our study identifies two new susceptibility loci and suggests new pathogenic mechanisms of ALS.
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| 4. |
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| 5. |
- Darakchieva, Vanya, et al.
(author)
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Unravelling the free electron behavior in InN
- 2008
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In: Optoelectronic and Microelectronic Materials and Devices, 2008. - : IEEE. - 9781424427161 ; , s. 90-97
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Conference paper (peer-reviewed)abstract
- Precise measurement of the optical Hall effect in InN using magneto-optical generalized ellipsometry at IR and THz wavelengths, allows us to decouple the surface accumulation and bulk electron densities in InN films by non-contact optical means and further to precisely measure the effective mass and mobilities for polarizations parallel and perpendicular to the optical axis. Studies of InN films with different thicknesses, free electron densities and surface orientations enable an intricate picture of InN free electron properties to emerge. Striking findings on the scaling factors of the bulk electron densities with film thickness further supported by transmission electron microscopy point to an additional thickness dependent doping mechanism unrelated to dislocations. Surface electron accumulation is observed to occur not only at polar but also at non-polar and semi-polar wurtzite InN, and zinc blende InN surfaces. The persistent surface electron density shows a complex behavior with bulk density and surface orientation. This behavior might be exploited for tuning the surface charge in InN.
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| 6. |
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| 7. |
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| 8. |
- Zhang, Guojie, et al.
(author)
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Comparative genomics reveals insights into avian genome evolution and adaptation
- 2014
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1311-1320
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Journal article (peer-reviewed)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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| 9. |
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| 10. |
- Chang, Yachao, et al.
(author)
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Construction and assessment of reduced oxidation mechanisms using global sensitivity analysis and uncertainty analysis
- 2019
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In: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 37:1, s. 751-761
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Journal article (peer-reviewed)abstract
- The global sensitivity analysis is an effective method to assess the performance of a chemical reaction mechanism. In the present study, the uncertainty analysis and the global sensitivity analysis of a detailed chemical mechanism of n-heptane are first performed based on the Monte Carlo method. The source of the prediction uncertainties of the C0-C7 sub-mechanisms and the reaction classes in the fuel-specific sub-mechanism of the detailed mechanism are determined by the global sensitivity analysis. Then, based on the results, a reduced mechanism for n-heptane oxidation is developed. To assess the performance of the reduced mechanism, the nominal model prediction and the frequency distribution of the ignition delay times using the present reduced mechanism are compared with those of the detailed mechanism and two additional reduced mechanisms obtained by the directed relation graph with error propagation (DRGEP) method. The results indicate that the predictions from the present reduced mechanism and the reduced mechanism with 305 species satisfactorily agree that of the detailed mechanism. Furthermore, the discrepancy of the predictions among these mechanisms is discussed based on the Spearman Rank Correlation analysis. It is found that, for the reduced mechanism with 120 species, the optimization of the reaction rate constants significantly improves the nominal model prediction of the ignition delay time, whereas its influence on the range and profile of the frequency distribution is rather weak due to the intrinsic relationship among the reactions being broken in the reduced mechanism.
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| 11. |
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| 12. |
- Chen, Lei, et al.
(author)
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A machine learning model that outperforms conventional global subseasonal forecast models
- 2024
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In: NATURE COMMUNICATIONS. - 2041-1723. ; 15:1
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Journal article (peer-reviewed)abstract
- Skillful subseasonal forecasts are crucial for various sectors of society but pose a grand scientific challenge. Recently, machine learning-based weather forecasting models outperform the most successful numerical weather predictions generated by the European Centre for Medium-Range Weather Forecasts (ECMWF), but have not yet surpassed conventional models at subseasonal timescales. This paper introduces FuXi Subseasonal-to-Seasonal (FuXi-S2S), a machine learning model that provides global daily mean forecasts up to 42 days, encompassing five upper-air atmospheric variables at 13 pressure levels and 11 surface variables. FuXi-S2S, trained on 72 years of daily statistics from ECMWF ERA5 reanalysis data, outperforms the ECMWF's state-of-the-art Subseasonal-to-Seasonal model in ensemble mean and ensemble forecasts for total precipitation and outgoing longwave radiation, notably enhancing global precipitation forecast. The improved performance of FuXi-S2S can be primarily attributed to its superior capability to capture forecast uncertainty and accurately predict the Madden-Julian Oscillation (MJO), extending the skillful MJO prediction from 30 days to 36 days. Moreover, FuXi-S2S not only captures realistic teleconnections associated with the MJO but also emerges as a valuable tool for discovering precursor signals, offering researchers insights and potentially establishing a new paradigm in Earth system science research. This paper introduces FuXi-S2S, a machine-learning model that outperforms conventional numerical weather prediction models at subseasonal timescales globally, extending the skillful Madden-Julian Oscillation prediction form 30 days to 36 days.
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| 13. |
- Darakchieva, Vanya, 1971-, et al.
(author)
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Effects of strain and composition on the lattice parameters and applicability of Vegard's rule in Al-rich Al1-x Inx N films grown on sapphire
- 2008
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:10, s. 103513-
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Journal article (peer-reviewed)abstract
- The lattice parameters and strain evolution in Al1-x In x N films with 0.07≤x≤0.22 grown on GaN-buffered sapphire substrates by metal organic vapor phase epitaxy have been studied by reciprocal space mapping. Decoupling of compositional effects on the strain determination was accomplished by measuring the In contents in the films both by Rutherford backscattering spectrometry (RBS) and x-ray diffraction (XRD). Differences between XRD and RBS In contents are discussed in terms of compositions and biaxial strain in the films. It is suggested that strain plays an important role for the observed deviation from Vegard's rule in the case of pseudomorphic films. On the other hand, a good agreement between the In contents determined by XRD and RBS is found for Al1-x Inx N films with low degree of strain or partially relaxed, suggesting applicability of Vegard's rule in the narrow compositional range around the lattice matching to GaN. © 2008 American Institute of Physics.
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| 14. |
- Darakchieva, Vanya, et al.
(author)
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Lattice parameters, deviations from Vegards rule, and E-2 phonons in InAlN
- 2008
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:26, s. 261908-
-
Journal article (peer-reviewed)abstract
- The lattice parameters of InxAl1-xN in the whole compositional range are studied using first-principle calculations. Deviations from Vegards rule are obtained via the bowing parameters, delta(a)=0.0412 +/- 0.0039 A and delta(c)=-0.060 +/- 0.010 A, which largely differ from previously reported values. Implications of the observed deviations from Vegards rule on the In content extracted from x-ray diffraction are discussed. We also combine these results with x-ray diffraction and Raman scattering studies on InxAl1-xN nanocolumns with 0.627 <= x <= 1 and determine the E-2 phonon frequencies versus In composition in the scarcely studied In-rich compositional range.
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| 15. |
- Darakchieva, Vanya, 1971-, et al.
(author)
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Strain and compositional analyzes of Al-rich Al1-xInxN alloys grown by MOVPE : impact on the applicability of Vegard's rule
- 2008
-
In: Physica Status Solidi (C) Current Topics in Solid State Physics. - : Wiley. ; , s. 1859-1862
-
Conference paper (peer-reviewed)abstract
- We have studied composition and strain in Al1–xInxN films with 0.128≤ x≤ 0.22 grown on GaN-buffered sapphire substrates by metalorganic vapor phase epitaxy. A good agreement between the In contents determined by Rutherford backscattering spectrometry (RBS) and Xray diffraction (XRD) is found for x≤ 18, suggesting applicability of Vegard's rule in the narrow compositional range around the lattice matching to GaN. The increase of the In content up to x = 0.22 leads to a formation of sub-layers with a higher composition, accompanied by deviations from Vegard's rule. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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| 16. |
- Du, Banghua, et al.
(author)
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Energy management and performance analysis of an off-grid integrated hydrogen energy utilization system
- 2024
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In: Energy Conversion and Management. - 0196-8904. ; 299
-
Journal article (peer-reviewed)abstract
- In integrated hydrogen energy utilization systems, due to the low efficiency of hydrogen/electricity conversion, coordination of energy management and efficient waste heat recovery is required to optimize performance. To address this challenge, this paper presents a comprehensive and sophisticated modeling and energy management strategy to enhance the off-grid energy utilization rate while prolonging the main components' lifetime. The developed model incorporates multiphase flow and heat transport balance for electricity and heat production, enabling a highly accurate representation of real-world behaviors of the system. The proposed off-grid operation strategy is complemented by a designed heat recovery scheme, ensuring the use of energy resources and waste heat. In addition, the proposed energy management strategy monitors the real-time status of each subsystem, actively reducing the number of harmful start-stop cycles of the hydrogen production system, thereby mitigating short-term power impacts and delaying its aging. Specifically, the voltage degradation of the reduction cell is reduced from 4.67 mV to 4.48 mV, the energy utilization rate is increased from 47.6 % to 53.9 %, and the energy efficiency of fuel cells significantly increases from 53.6 % to 78.1 %.
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| 17. |
- Fang, Zhiwei, et al.
(author)
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Structural stability and aqueous durability of Cs incorporation into BaAl2Ti6O16 hollandite
- 2022
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In: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 565, s. 153716-
-
Journal article (peer-reviewed)abstract
- Hollandite ceramics are well-recognized as a promising host for immobilizing radioactive cesium. In the present paper, the [BaxCsy][(Al3+,Ti3+)(2x +y)Ti-8-2x-y(4+)]O-16 (0.4 <= x, y <= 0.8) ceramics were fabricated to in-vestigate the effect of incorporated Cs on structural stability and durability of (Ba,Cs)(Al,Ti)(8)O-16 ceramics with Cs-incorporated. It was found that the sintered samples at 1250 degrees C show a pure hollandite phase with tetragonal structure (I4/m) and high Cs retention. Moreover, the synthesized (Ba,Cs)(Al,Ti)(8)O-16 ceramics exhibit an excellent aqueous stability and the normalized Cs release rate is 2.82 (+/- 0.27) x10(-3) g m(-2) d(-1) after 28 days. All these results reveal that (Ba,Cs)(Al,Ti)(8)O-16 is a promising candidate as a Cs-waste form.
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| 18. |
- Fu, Pan, et al.
(author)
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Metasurface Enabled On-Chip Generation and Manipulation of Vector Beams from Vertical Cavity Surface-Emitting Lasers
- 2023
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In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; In Press
-
Journal article (peer-reviewed)abstract
- Metasurface polarization optics that consist of 2D array of birefringent nano-antennas have proven remarkable capabilities to generate and manipulate vectorial fields with subwavelength resolution and high efficiency. Integrating this new type of metasurface with the standard vertical cavity surface-emitting laser (VCSEL) platform enables an ultracompact and powerful solution to control both phase and polarization properties of the laser on a chip, which allows to structure a VCSEL into vector beams with on-demand wavefronts. Here, this concept is demonstrated by directly generating versatile vector beams from commercially available VCSELs through on-chip integration of high-index dielectric metasurfaces. Experimentally, the versatility of the approach for the development of vectorial VCSELs are validated by implementing a variety of functionalities, including directional emission of multibeam with specified polarizations, vectorial holographic display, and vector vortex beams generations. Notably, the proposed vectorial VCSELs integrated with a single layer of beam shaping metasurface bypass the requirements of multiple cascaded optical components, and thus have the potential to promote the advancements of ultracompact, lightweight, and scalable vector beams sources, enriching and expanding the applications of VCSELs in optical communications, laser manipulation and processing, information encryption, and quantum optics.
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| 19. |
- Kristan, Matej, et al.
(author)
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The Ninth Visual Object Tracking VOT2021 Challenge Results
- 2021
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In: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2021). - : IEEE COMPUTER SOC. - 9781665401913 ; , s. 2711-2738
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Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge VOT2021 is the ninth annual tracker benchmarking activity organized by the VOT initiative. Results of 71 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in recent years. The VOT2021 challenge was composed of four sub-challenges focusing on different tracking domains: (i) VOT-ST2021 challenge focused on short-term tracking in RGB, (ii) VOT-RT2021 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2021 focused on long-term tracking, namely coping with target disappearance and reappearance and (iv) VOT-RGBD2021 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2021 dataset was refreshed, while VOT-RGBD2021 introduces a training dataset and sequestered dataset for winner identification. The source code for most of the trackers, the datasets, the evaluation kit and the results along with the source code for most trackers are publicly available at the challenge website(1).
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| 20. |
- Li, Wei, et al.
(author)
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Non-lab and semi-lab algorithms for screening undiagnosed diabetes : A cross-sectional study
- 2018
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In: EBioMedicine. - : ELSEVIER SCIENCE BV. - 2352-3964. ; 35, s. 307-316
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Journal article (peer-reviewed)abstract
- Background: The terrifying undiagnosed rate and high prevalence of diabetes have become a public emergency. A high efficiency and cost-effective early recognition method is urgently needed. We aimed to generate innovative, user-friendly nomograms that can be applied for diabetes screening in different ethnic groups in China using the non-lab or noninvasive semi-lab data. Methods: This multicenter, multi-ethnic, population-based, cross-sectional study was conducted in eight sites in China by enrolling subjects aged 20-70. Sociodemographic and anthropometric characteristics were collected. Blood and urine samples were obtained 2 h following a standard 75 g glucose solution. In the final analysis, 10,794 participants were included and randomized into model development (n - 8096) and model validation (n = 2698) group with a ratio of 3:1. Nomograms were developed by the stepwise binary logistic regression. The nomograms were validated internally by a bootstrap sampling method in the model development set and externally in the model validation set. The area under the receiver operating characteristic curve (AUC) was used to assess the screening performance of the nomograms. Decision curve analysis was applied to calculate the net benefit of the screening model. Results: The overall prevalence of undiagnosed diabetes was 9.8% (1059/10794) according to ADA criteria. The non-lab model revealed that gender, age, body mass index, waist circumference, hypertension, ethnicities, vegetable daily consumption and family history of diabetes were independent risk factors for diabetes. By adding 2 h post meal glycosuria qualitative to the non-lab model, the semi-lab model showed an improved Akaike information criterion (AIC: 4506 to 3580). The AUC of the semi-lab model was statistically larger than the non-lab model (0.868 vs 0.763, P < 0.001). The optimal cutoff probability in semi-lab and non-lab nomograms were 0.088 and 0.098, respectively. The sensitivity and specificity were 76.3% and 81.6%, respectively in semi-lab nomogram, and 72.1% and 673% in non-lab nomogram at the optimal cut off point. The decision curve analysis also revealed a bigger decrease of avoidable OGTT test (52 per 100 subjects) in the semi-lab model compared to the non-lab model (36 per 100 subjects) and the existed New Chinese Diabetes Risk Score (NCDRS, 35 per 100 subjects). Conclusion: The non-lab and semi-lab nomograms appear to be reliable tools for diabetes screening, especially in developing countries. However, the semi-lab model outperformed the non-lab model and NCDRS prediction systems and might be worth being adopted as decision support in diabetes screening in China.
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| 21. |
- Li, Xiaoting, et al.
(author)
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Nano-confinement-inspired metal organic framework/polymer composite separation membranes
- 2020
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:33, s. 17212-17218
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Journal article (peer-reviewed)abstract
- A defect-free, robust and selective barrier is essential for manufacturing membranes with targeted high permeability and selectivity. Here we report a new route to engineering a separation composite membrane by confining both channels in nanoscale metal organic frameworks (MOFs) and charges in a polyelectrolyte in the inner space of a porous supportviaa counter-diffusion method. A simple thermal annealing treatment of the interface between the MOF, polymer and support favorably reduced voids inside this nano-confinement environment. As this composite membrane combines both the support and barrier as one, it minimizes mass transfer resistance of water molecules. In a separation test, it readily achieved the state-of-the-art permeance. This simple chemical approach to upgrade membrane structures will offer wide opportunities in separation devices.
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| 22. |
- Li, Yibei, et al.
(author)
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A Duality-Based Approach to Inverse Kalman Filtering
- 2023
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In: 22nd IFAC World Congress Yokohama, Japan, July 9-14, 2023. - : Elsevier BV. ; , s. 10258-10263
-
Conference paper (peer-reviewed)abstract
- In this paper, the inverse Kalman filtering problem is addressed using a duality-based framework, where certain statistical properties of uncertainties in a dynamical model are recovered from observations of its posterior estimates. The duality relation in inverse filtering and inverse optimal control is established. It is shown that the inverse Kalman filtering problem can be solved using results from a well-posed inverse linear quadratic regulator. Identifiability of the considered inverse filtering model is proved and a unique covariance matrix is recovered by a least squares estimator, which is also shown to be statistically consistent. Effectiveness of the proposed methods is illustrated by numerical simulations.
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| 23. |
- Li, Yibei, et al.
(author)
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Inverse Kalman Filtering for Systems with Correlated Noises
- 2023
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In: 2023 62nd IEEE Conference on Decision and Control, CDC 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 3626-3631
-
Conference paper (peer-reviewed)abstract
- This paper focuses on two inverse problems of the Kalman filter in which the process and measurement noises are correlated. The unknown covariance matrix in a stochastic system is reconstructed from observations of its posterior beliefs. For the standard inverse Kalman filtering problem, a novel duality-based formulation is proposed, where a well-defined inverse optimal control (IOC) problem is solved instead. Identifiability of the underlying model is proved, and a least squares estimator is designed that is statistically consistent. The time-invariant case using the steady-state Kalman gain is further studied. Since this inverse problem is ill-posed, a canonical class of covariance matrices is constructed, which can be uniquely identified from the dataset with asymptotic convergence. Finally, the performances of the proposed methods are illustrated by numerical examples.
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| 24. |
- Li, Yibei, et al.
(author)
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Inverse Kalman filtering problems for discrete-time systems
- 2024
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In: Automatica. - : Elsevier BV. - 0005-1098 .- 1873-2836. ; 163
-
Journal article (peer-reviewed)abstract
- In this paper, several inverse Kalman filtering problems are addressed, where unknown parameters and/or inputs in a filtering model are reconstructed from observations of the posterior estimates that can be noisy or incomplete. In particular, duality in inverse filtering and inverse optimal control is studied. It is shown that identifiability and solvability of the inverse Kalman filtering is closely related to that of an inverse linear quadratic regulator (LQR). Covariance matrices of model uncertainties are estimated by solving a well-posed inverse LQR problem. Identifiability of the considered inverse filtering models is established and least squares estimators are designed to be statistically consistent. In addition, algorithms are proposed to reconstruct the unknown sensor parameters as well as raw sensor measurements. Effectiveness and efficiency of the proposed methods are illustrated by numerical simulations.
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| 25. |
- Liu, Bo, et al.
(author)
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Zircon U-Pb-Hf Isotopes and Whole-Rock Geochemistry of the “Kulumudi Formation” from the Laofengkou Area (West Junggar) : Implications of the Construction of a Juvenile Arc in the Junggar–Balkhash Ocean
- 2024
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In: Minerals. - 2075-163X. ; 14:1
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Journal article (peer-reviewed)abstract
- The properties of ancient magmatic arcs are crucial for understanding the tectonic evolution of the Central Asian Orogenic Belt. The Middle Devonian Kulumudi Formation in the Laofengkou area of West Junggar lacks accurate chronological data constraints, which hampers the knowledge of the nature of the Late Paleozoic magmatic arcs in the West Junggar and circum-Balkhash areas. In this contribution, samples of pyroclastic rocks and sedimentary rocks were collected from the volcano–sedimentary strata of the Kulumudi Formation. Petrography, zircon U-Pb-Hf isotopic analysis and whole-rock geochemistry were carried out to constrain the age and the tectonic setting of the Kulumudi Formation. The zircon U-Pb age of the lithic crystal tuff from the Kulumudi Formation on the northeast side of the Alemale Mountains was 386 ± 2 Ma, accurately indicating that this rock unit formed during the Middle Devonian. However, the fine sandstone near the Huojierte Mongolian Township, originally assigned as the “Kulumudi Formation”, yielded a maximum depositional age of 341 ± 3 Ma. Combined with the stratigraphic contact, this rock unit was redefined to belong to the Lower Carboniferous Jiangbasitao Formation. According to the whole-rock geochemistry study, the lithic crystal tuff of the Kulumudi Formation was characterized as medium potassium–calc–alkaline series rock, which is relatively enriched in light rare earth elements and large ion lithophile elements (i.e., Rb, Ba, K) and depleted in high-field-strength elements (i.e., Nb, Ta, Ti), showing similar geochemical characteristics to the volcanic arc rocks. By contrast, the fine sandstone from the Jiangbasitao Formation had Al2O3/SiO2 (0.25–0.29) and K2O/Na2O (1.29–1.72) ratios close to those derived from the continental arc and active continental margin and was characterized as part of the continental arc field in the La-Th-Sc and Th-Sc-Zr/10 tectonic discrimination diagrams. Zircon Hf isotope analysis showed that the εHf(t) values of the Kulumudi Formation were +5.6–+12.8, and those of the Jiangbasitao Formation were +11.43–+15.48, both of which show highly positive juvenile characteristics. The above data indicate that the Kulumudi Formation and Jiangbasitao Formation both formed in a juvenile arc setting with ocean–continent subduction. Combined with the previous work, it was concluded that the southward subduction of the ocean basin represented by the Darbut–Karamay ophiolitic mélanges beneath the newly accreted arc crustal segments produced a juvenile arc with positive Hf isotope characteristics.
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