| 1. |
- Lin, Baojun, et al.
(författare)
-
Balancing the pre-aggregation and crystallization kinetics enables high efficiency slot-die coated organic solar cells with reduced non-radiative recombination losses
- 2020
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 13:8, s. 2467-2479
-
Tidskriftsartikel (refereegranskat)abstract
- Slot-die coating being compatible with the roll-to-roll technique has been regarded as a promising tool for upscaling the manufacturing of organic solar cells (OSCs). However, there has been a significant gap between the efficiencies of the state-of-the-art spin-coated devices and the scalable processed devices. The active layer morphology is crucial to achieve high efficiency in OSCs, which depends on the conditions of film fabrication. To figure out and optimize the slot-die coating process, a deeper understanding of the film formation kinetics is important. Herein, in situ measurements of the slot-die coating process based on the PM7:IT4F system are demonstrated to illustrate the aggregation and crystallization evolution at various die temperatures and substrate temperatures. OSCs with a high power conversion efficiency of 13.2% are achieved at 60 degrees C die temperature/60 degrees C substrate temperature due to the improved exciton dissociation, charge transport and suppressed non-radiative charge recombination. The optimized morphology is attributed to the balanced polymer pre-aggregation and small molecule crystallization kinetics. The unsuitable die temperature leads to overlarge phase separation and consequently inefficient exciton dissociation while the improper substrate temperature results in weak crystallization and the following shrunken carrier lifetime with strong non-radiative combination. This work provides fundamental understanding on the correlations among processing methodology, solution pre-aggregation, morphology formation kinetics, device physics and device performance and affords guidance for device optimization in scalable manufacturing.
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| 2. |
- Xu, Xiaofeng, et al.
(författare)
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Large-Area, Semitransparent, and Flexible All-Polymer Photodetectors
- 2018
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 28:48
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Tidskriftsartikel (refereegranskat)abstract
- Photodetectors, converting optical signals from specific wavelengths to electrical signals, have many applications on photoimaging, optical communication, and environmental monitoring. Solution-processed organic photodetectors (OPDs) based on organic materials emerge promise especially for wearable electronics and smart buildings. In this work, new all-polymer photodetectors (all-PPDs) are developed based on bulk-heterojunction active layers which incorporate a donor polymer and an acceptor polymer. The inverted all-PPDs exhibit outstanding external quantum efficiency over 70%, low dark current density (J(d)) of 1.1 x 10(-8) A cm(-2), and high detectivity (D*) over 3.0 x 10(12) Jones with planar response over the entire visible range. It is one of the best-performing all-PPDs reported so far and is also comparable with many organic and inorganic photodetectors. By using lamination technique, large-area, semitransparent, flexible, and "fully" polymeric photodetectors are successfully fabricated for the first time, with D* over 10(11) Jones for double-side light detection. The results highlight the great potential for producing high-performance all-PPDs by taking advantages of various device architecture and solution-processing techniques.
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| 3. |
- Zhou, Ke, et al.
(författare)
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Molecular Orientation of Polymer Acceptor Dominates Open-Circuit Voltage Losses in All-Polymer Solar Cells
- 2019
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Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 4:5, s. 1057-1064
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Tidskriftsartikel (refereegranskat)abstract
- Low open-circuit voltage (V-oc) induced by energy loss in organic solar cells is considered to be one of the most influencing factors limiting device performance, in which morphology of the active layer plays a crucial role in determining energy loss. By employing a bilayer structure of the P3HT:N2200 all-polymer system, we have identified the isolated impact of a molecular packing structure on device V-oc with analysis of energy loss processes. Thermal annealing and various solvents were used to control molecular orientation in P3HT:N2200 bilayer devices, in which different V-oc spanning from 0.45 to 0.54 V could be obtained. It was found that energy of charge-transfer state (E-ct) differed in these bilayer devices. Besides, increased charge recombination could be observed in bilayer devices when N2200 layers exhibited face-on orientation, which caused an additional energy loss and decreased V-oc. Our results suggest that rational control of polymer molecular orientation is essential to reduce the energy loss and ultimately achieve high V-oc in all-polymer solar cells.
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| 4. |
- Zhou, Ke, et al.
(författare)
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pi-pi Stacking Distance and Phase Separation Controlled Efficiency in Stable All-Polymer Solar Cells
- 2019
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of the active layer plays a crucial role in determining device performance and stability for organic solar cells. All-polymer solar cells (All-PSCs), showing robust and stable morphologies, have been proven to give better thermal stability than their fullerene counterparts. However, outstanding thermal stability is not always the case for polymer blends, and the limiting factors responsible for the poor thermal stability in some All-PSCs, and how to obtain higher efficiency without losing stability, still remain unclear. By studying the morphology of poly [2,3-bis (3-octyloxyphenyl) quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl](TQ1)/poly[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b ]dithiophene-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl]] (PCE10)/PNDI-T10 blend systems, we found that the rearranged molecular packing structure and phase separation were mainly responsible for the poor thermal stability in devices containing PCE10. The TQ1/PNDI-T10 devices exhibited an improved PCE with a decreased pi-pi stacking distance after thermal annealing; PCE10/PNDI-T10 devices showed a better pristine PCE, however, thermal annealing induced the increased pi-pi stacking distance and thus inferior hole conductivity, leading to a decreased PCE. Thus, a maximum PCE could be achieved in a TQ1/PCE10/PNDI-T10 (1/1/1) ternary system after thermal annealing resulting from their favorable molecular interaction and the trade-off of molecular packing structure variations between TQ1 and PCE10. This indicates that a route to efficient and thermal stable All-PSCs can be achieved in a ternary blend by using material with excellent pristine efficiency, combined with another material showing improved efficiency under thermal annealing.
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| 5. |
- Beck, Dominik, et al.
(författare)
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Integrative analysis of next generation sequencing for small non-coding RNAs and transcriptional regulation in Myelodysplastic Syndromes
- 2011
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Ingår i: BMC Medical Genomics. - : Springer Science and Business Media LLC. - 1755-8794. ; 4:19, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMyelodysplastic Syndromes (MDSS) are pre-leukemic disorders with increasing incident rates worldwide, but very limited treatment options. Little is known about small regulatory RNAs and how they contribute to pathogenesis, progression and transcriptome changes in MDS.MethodsPatients' primary marrow cells were screened for short RNAs (RNA-seq) using next generation sequencing. Exon arrays from the same cells were used to profile gene expression and additional measures on 98 patients obtained. Integrative bioinformatics algorithms were proposed, and pathway and ontology analysis performed.ResultsIn low-grade MDS, observations implied extensive post-transcriptional regulation via microRNAs (miRNA) and the recently discovered Piwi interacting RNAs (piRNA). Large expression differences were found for MDS-associated and novel miRNAs, including 48 sequences matching to miRNA star (miRNA*) motifs. The detected species were predicted to regulate disease stage specific molecular functions and pathways, including apoptosis and response to DNA damage. In high-grade MDS, results suggested extensive post-translation editing via transfer RNAs (tRNAs), providing a potential link for reduced apoptosis, a hallmark for this disease stage. Bioinformatics analysis confirmed important regulatory roles for MDS linked miRNAs and TFs, and strengthened the biological significance of miRNA*. The "RNA polymerase II promoters" were identified as the tightest controlled biological function. We suggest their control by a miRNA dominated feedback loop, which might be linked to the dramatically different miRNA amounts seen between low and high-grade MDS.DiscussionThe presented results provide novel findings that build a basis of further investigations of diagnostic biomarkers, targeted therapies and studies on MDS pathogenesis.
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| 6. |
- Jin, Yunzhe, et al.
(författare)
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Effects of in-situ stress on heat transfer in fracture networks
- 2024
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Ingår i: Geomechanics for Energy and the Environment. - : Elsevier BV. - 2352-3808. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- Stress-induced fracture deformation is the principal cause for permeability change in geothermal systems. This study focuses on the influence of the nonlinear deformation and dilation effect of fractures on the geothermal system under the action of in-situ stress. By adopting a nonlinear constitutive model of rock fractures and embedding discrete fracture networks, numerical studies are first conducted to investigate the effects of different in-situ stress schemes on fracture aperture evolution using a rigid-body spring method. Based on the anisotropic aperture field of the fracture network caused by the in-situ stress, a finite element method is then used to study the flow and heat transfer process. The effects of different stress schemes on the heat flow transfer process are analyzed. Numerical simulation results show that when the ratio of horizontal to vertical stresses is not sufficient to cause shear dilation effects, the nonlinear normal deformation is the main factor affecting flow and heat transfer. In this case, the heat extraction efficiency is reduced. As the stress ratio increases, the shear dilation gradually becomes the dominant mechanism, and the heat extraction performance is improved. The obtained results provide a practical guide for geothermal site siting and optimizing heat extraction efficiency in geothermal reservoirs.
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| 7. |
- Jin, Yunzhe, et al.
(författare)
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Experimental and numerical simulation study on the evolution of mechanical properties of granite after thermal treatment
- 2024
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Ingår i: Computers and geotechnics. - : Elsevier BV. - 0266-352X .- 1873-7633. ; 172
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Tidskriftsartikel (refereegranskat)abstract
- High temperature significantly influences the mechanical properties of granite, which is relevant to various engineering applications, including geothermal energy extraction. The objective of this study is to investigate the meso-mechanics of granite, specifically focusing on the formation of thermal cracks and the temperature-dependent mechanical properties in heterogeneous rock. Firstly, we heat the granite to 25–1000 ℃ by muffle furnace. Following this, we conduct triaxial compression tests with 0–20 MPa confining pressures on the heated-specimens cooled by cold water. Subsequently, we combine the grain-based model (GBM) and the finite-discrete element method (FDEM) to simulate the heat treatment process and the triaxial experiments. We calibrate the micromechanical parameters of granite by experimental results. Results show that the mechanism behind the formation of thermal cracks in granite subjected to high-temperature is the differential thermal expansion coefficients of mineral particles in granites, leading to the degradation of mechanical properties in thermal-treated granite. The temperature threshold for the formation of thermal cracks is between 500 °C and 550 °C. Particularly, the stress-strain curve of granite exhibits ideal elastic-plastic characteristics under temperature is 1000 °C. These results can help to demonstrate the temperature-dependent evolution of mechanical properties of crystalline rocks, providing a theoretical basis for the utilization of engineering applications.
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| 8. |
- Jing, Yumei, et al.
(författare)
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A Single-Electron Transistor Made of a 3D Topological Insulator Nanoplate
- 2019
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 31:42
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Tidskriftsartikel (refereegranskat)abstract
- Quantum confined devices of 3D topological insulators are proposed to be promising and of great importance for studies of confined topological states and for applications in low-energy-dissipative spintronics and quantum information processing. The absence of energy gap on the topological insulator surface limits the experimental realization of a quantum confined system in 3D topological insulators. Here, the successful realization of single-electron transistor devices in Bi2Te3 nanoplates using state-of-the-art nanofabrication techniques is reported. Each device consists of a confined central island, two narrow constrictions that connect the central island to the source and drain, and surrounding gates. Low-temperature transport measurements demonstrate that the two narrow constrictions function as tunneling junctions and the device shows well-defined Coulomb current oscillations and Coulomb-diamond-shaped charge-stability diagrams. This work provides a controllable and reproducible way to form quantum confined systems in 3D topological insulators, which should greatly stimulate research toward confined topological states, low-energy-dissipative devices, and quantum information processing.
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| 9. |
- Lin, Xiongwei, et al.
(författare)
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Noise reduction optimization of sound sensor based on a Conditional Generation Adversarial Network
- 2021
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1873:1
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Konferensbidrag (refereegranskat)abstract
- To address the problems in the traditional speech signal noise elimination methods, such as the residual noise, poor real-time performance and narrow applications a new method is proposed to eliminate network voice noise based on deep learning of conditional generation adversarial network. In terms of the perceptual evaluation of speech quality (PESQ) and shorttime objective intelligibility measure (STOI) functions used as the loss function in the neural network, which were used as the loss function in the neural network, the flexibility of the whole network was optimized, and the training process of the model simplified. The experimental results indicate that, under the noisy environment, especially in a restaurant, the proposed noise reduction scheme improves the STOI score by 26.23% and PESQ score by 17.18%, respectively, compared with the traditional Wiener noise reduction algorithm. Therefore, the sound sensor's noise reduction scheme through our approach has achieved a remarkable noise reduction effect, more useful information transmission, and stronger practicability.
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| 10. |
- Ng, Theam Foo, et al.
(författare)
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Justification of Fuzzy Declustering Vector Quantization Modeling in Classification of Genotype-Image Phenotypes
- 2010
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Konferensbidrag (refereegranskat)abstract
- With the fast development of multi‐dimensional data compression and pattern classification techniques, vector quantization (VQ) has become a system that allows large reduction of data storage and computational effort. One of the most recent VQ techniques that handle the poor estimation of vector centroids due to biased data from undersampling is to use fuzzy declustering‐based vector quantization (FDVQ) technique. Therefore, in this paper, we are motivated to propose a justification of FDVQ based hidden Markov model (HMM) for investigating its effectiveness and efficiency in classification of genotype‐image phenotypes. The performance evaluation and comparison of the recognition accuracy between a proposed FDVQ based HMM (FDVQ‐HMM) and a well‐known LBG (Linde, Buzo, Gray) vector quantization based HMM (LBG‐HMM) will be carried out. The experimental results show that the performances of both FDVQ‐HMM and LBG‐HMM are almost similar. Finally, we have justified the competitiveness of FDVQ‐HMM in classification of cellular phenotype image database by using hypotheses t‐test. As a result, we have validated that the FDVQ algorithm is a robust and an efficient classification technique in the application of RNAi genome‐wide screening image data.
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| 11. |
- Pham, Tuan D, et al.
(författare)
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A novel image feature for nuclear-phase classification in high content screening
- 2007
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Ingår i: Advances in Mass Data Analysis of Signals and Images in Medicine, Biotechnology and Chemistry. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783540762997 - 9783540763000 ; , s. 84-93
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Bokkapitel (refereegranskat)abstract
- Cellular imaging is an exciting area of research in computational life sciences, which provides an essential tool for the study of diseases at the cellular level. In particular, to faciliate the usefulness of cellular imaging for high content screening, image analysis and classification need to be automated. In fact the task of image classification is an important component for any computerized imaging system which aims to automate the screening of high-content, high-throughput fluorescent images of mitotic cells. It can help biomedical and biological researchers to speed up the analysis of mitotic data at dynamic ranges for various applications including the study of the complexity of cell processes, and the screening of novel anti-mitotic drugs as potential cancer therapeutic agents. We propose in this paper a novel image feature based on a spatial linear predictive model. This type of image feature can be effectively used for vector-quantization based classification of nuclear phases. We used a dataset of HeLa cells line to evaluate and compare the proposed method on the classification of nuclear phases. Experimental results obtained from the new feature are found to be superior to some recently published results using the same dataset.
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| 12. |
- Pham, Tuan D, et al.
(författare)
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Analysis of Major Adverse Cardiac Events with Entropy-Based Complexity
- 2010
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Ingår i: Information Technologies in Biomedicine. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642131042 - 9783642131059 ; , s. 261-272
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Bokkapitel (refereegranskat)abstract
- Major adverse cardiac events (MACE) are referred to as unsuspected heart attacks that include death, myocardial infarction and target lesion revascularization. Feature extraction and classification methods for such cardiac events are useful tools that can be applied for biomarker discovery to allow preventive treatment and healthy-life maintenance. In this study we present an entropy-based analysis of the complexity of MACE-related mass spectrometry signals, and an effective model for classifying MACE and control complexity-based features. In particular, the geostatistical entropy is analytically rigorous and can provide better information about the predictability of this type of MACE data than other entropy-based methods for complexity analysis of biosignals. Information on the complexity of this type of time-series data can expand our knowledge about the dynamical behavior of a cardiac model and be useful as a novel feature for early prediction.
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| 13. |
- Pham, Tuan D, et al.
(författare)
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Computational Models For Life Sciences (CMLS '07)
- 2007
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Konferensbidrag (refereegranskat)abstract
- This conference proceedings text features research papers that address novel applications of computer, physical, engineering and mathematical models for solving modern challenging problems in life sciences. All the papers, presented at the Computational Models for Life Sciences conference held in 2007, have been peer-reviewed. They cover a huge range of topics, including image analysis, computer vision, and pattern analysis and classification, among many others.
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| 14. |
- Pham, Tuan D, et al.
(författare)
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Fuzzy information fusion of classification models for high-throughput image screening of cancer cells in time-lapse microscopy
- 2007
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Ingår i: Journal of Knowledge-based & Intelligent Engineering Systems. - : IOS Press. - 1327-2314 .- 1875-8827. ; 11:4, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Bioimaging at molecular and cellular levels requires specific image analysis methods to help life scientists develop methodologies and hypotheses in biology and biomedicine. In particular, this is true when dealing with microscopic images of cells and vessels. To facilitate the automation of cell screening, we have developed methods based on vector quantization and Markov model for classification of cellular phases using time-lapse fluorescence microscopic image sequences. Because of ambiguity inherently existing in the labeling of cell-phase feature vectors, we proposed to use relaxation labeling technique to reduce uncertainty among cell-phase models having overlapping properties. To further improve the classification rate we applied a fuzzy fusion strategy for combining individual results obtained from multiple classifiers. Our proposed image-classification methods can be useful for the task of high-content cell-cycle screening which is essential for biomedical research in the study of structures and functions of cells and molecules.
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| 15. |
- Qu, Xiaobo, 1983, et al.
(författare)
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Jointly dampening traffic oscillations and improving energy consumption with electric, connected and automated vehicles: A reinforcement learning based approach
- 2020
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 257
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Tidskriftsartikel (refereegranskat)abstract
- It has been well recognized that human driver's limits, heterogeneity, and selfishness substantially compromise the performance of our urban transport systems. In recent years, in order to deal with these deficiencies, our urban transport systems have been transforming with the blossom of key vehicle technology innovations, most notably, connected and automated vehicles. In this paper, we develop a car following model for electric, connected and automated vehicles based on reinforcement learning with the aim to dampen traffic oscillations (stop-and-go traffic waves) caused by human drivers and improve electric energy consumption. Compared to classical modelling approaches, the proposed reinforcement learning based model significantly reduces the modelling constraints and has the capability of self-learning and self-correction. Experiment results demonstrate that the proposed model is able to improve travel efficiency by reducing the negative impact of traffic oscillations, and it can also reduce the average electric energy consumption.
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| 16. |
- Sakornsakolpat, Phuwanat, et al.
(författare)
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Genetic landscape of chronic obstructive pulmonary disease identifies heterogeneous cell-type and phenotype associations
- 2019
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 51:3, s. 494-505
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Tidskriftsartikel (refereegranskat)abstract
- Chronic obstructive pulmonary disease (COPD) is the leading cause of respiratory mortality worldwide. Genetic risk loci provide new insights into disease pathogenesis. We performed a genome-wide association study in 35,735 cases and 222,076 controls from the UK Biobank and additional studies from the International COPD Genetics Consortium. We identified 82 loci associated with P < 5 x 10-8; 47 of these were previously described in association with either COPD or population-based measures of lung function. Of the remaining 35 new loci, 13 were associated with lung function in 79,055 individuals from the SpiroMeta consortium. Using gene expression and regulation data, we identified functional enrichment of COPD risk loci in lung tissue, smooth muscle, and several lung cell types. We found 14 COPD loci shared with either asthma or pulmonary fibrosis. COPD genetic risk loci clustered into groups based on associations with quantitative imaging features and comorbidities. Our analyses provide further support for the genetic susceptibility and heterogeneity of COPD.
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| 17. |
- Wu, Jiaming, 1989, et al.
(författare)
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The cooperative sorting strategy for connected and automated vehicle platoons
- 2021
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Ingår i: Transportation Research, Part C: Emerging Technologies. - : Elsevier BV. - 0968-090X. ; 123
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a "cooperative vehicle sorting" strategy that seeks to optimally sort connected and automated vehicles (CAVs) in a multi-lane platoon to reach an ideally organized platoon. In the proposed method, a CAV platoon is firstly discretized into a grid system, where a CAV moves from one cell to another in discrete time-space domain. Then, the cooperative sorting problem is modeled as a path-finding problem in the graphic domain. The problem is solved by the deterministic A* algorithm with a stepwise strategy, where only one vehicle can move within a movement step. The resultant shortest path is further optimized with an integer linear programming algorithm to minimize the sorting time by allowing multiple movements within a step. To improve the algorithm running time and address multiple shortest paths, a distributed stochastic A* algorithm (DSA*) is developed by introducing random disturbances to the edge costs to break uniform paths (with equal path cost). Numerical experiments are conducted to demonstrate the effectiveness of the proposed DSA* method. The results report shorter sorting time and significantly improved algorithm running time due to the use of DSA*. In addition, we find that the optimization performance can be further improved by increasing the number of processes in the distributed computing system.
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| 18. |
- Wu, Xinchen, et al.
(författare)
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Core-satellite nanoassembly system with aptamer-conjugated Au@Ag nanoparticles for SERS detection of patulin in apples
- 2024
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Ingår i: Food Control. - : Elsevier. - 0956-7135 .- 1873-7129. ; 159
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Tidskriftsartikel (refereegranskat)abstract
- Patulin (PAT), a major contaminant in apples, poses a huge threat to human health as well as the economic sector. There is an urgent need to develop a sensitive, selective, and fast-responsive method to detect PAT in apples. However, one of the main challenges is overcoming the interferences of complex food matrices. In this study, we developed a highly sensitive competitive SERS sensor based on plasmonic nanoparticles modified by aptamers. The study utilized the formation of nanocomposites through aptamer-modified Au@Ag nanoparticles (NPs) and gold nano-stars (AuNSs) to induce high-intensity Raman signals from the SERS tag. Subsequently, in the presence of PAT, the nanocomposites underwent decomposition, evident through the significant decrease in SERS intensity. According to the standard curve established in this study, the detection limit was 0.0281 ng/mL. The competitive sensor was applied to spiked apple fruit and juice samples, indicating a recovery rate ranging from 91.98% to 102.94%. The excellent analytical performances and high sensitivity observed suggest the potential of the plasmonic nanocomposite sensing strategy in detecting PAT in real matrices.
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| 19. |
- Xiao, Yi, et al.
(författare)
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Correlation-based cluster-space transform for major adverse cardiac event prediction
- 2010
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Ingår i: IEEE International Conference on Systems Man and Cybernetics (SMC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781424465880 - 9781424465866 ; , s. 2003-2007
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the affect of variation of patterns in protein profiles to the identification of disease-specific biomarkers. A correlation-based cluster-space transform is applied to mass spectral data for predicting major adverse cardiac events (MACE). Training and testing data are transformed into cluster spaces by correlation distance based clustering, respectively. Data in the testing cluster that falls into a pair of training clusters is classified by a supervised classifier. Experiment results have shown that proteomic spectra of MACE which vary with certain patterns could be separated by the correlation-based clustering. The cluster-space transform allows better classification accuracy than single-clustered class method for separating disease and healthy samples.
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| 20. |
- Xiao, Yi, et al.
(författare)
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Symmetry-based presentation for stem-cell image segmentation
- 2011
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Konferensbidrag (refereegranskat)abstract
- Cancer stem cells have been isolated from many tumors, including breast, brain, colon, head and neck, lung, pancreas, and prostate tumors. Advances in stem cell biology and animal models help better characterization of cancer stem cells, including the cells of origin, molecular and cellular properties, functions in cancer initiation and development, treatment response, and drug resistance. An important and challenging task in image analysis of stem cells is the image segmentation. A difficulty is to segment aggregated cells that are deformed and occluded. Watershed transform and multiscale morphological operation are the common methods for this purpose, as they are robust against arbitrary shaping and the occlusion of cells. Notwithstanding their high robustness, the two methods are still limited in their applications in the cases with cells suffering perturbations and deformation during cell growth. In this paper, we propose a novel symmetry axis transformation for stem-cell image segmentation. Our algorithm was validated by its comparison with both watershed transform and multiscale morphological operation. Improved segmentation performance in terms of precision (up to 2.2% comparing to watershed; and up to 0.6% comparing to multiscale morphological operation) was achieved using 5197 cell images in which 291 cells are three mutually touching.
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| 21. |
- Xu, Jin Wei, et al.
(författare)
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A double thresholding method for cancer stem cell detection
- 2011
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Konferensbidrag (refereegranskat)abstract
- Image analysis of cancer cells is important for cancer diagnosis and therapy, because it recognized as the most efficient and effective way to observe its proliferation. For the purpose of adaptive and accurate cancer cell image segmentation, a double threshold segmentation method is proposed in this paper. Based on a single gray-value histogram of the RGB color space, a double threshold, the key parameters of threshold segmentation can be fixed by a fitted-curve of the RGB component histogram. As reasonable thresholds confirmed, binary segmentation dependent on two thresholds, will be put into practice and result in binary image. With the post-processing of mathematical morphology and division of whole image, the better segmentation result can be finally achieved. By the comparison with other advanced segmentation methods such as level set and active contour, the proposed double thresholding has been found as the simplest strategy with shortest processing time as well as highest accuracy. The proposed method can be effectively used in the detection and recognition of cancer stem cells in images.
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| 22. |
- Xue, Shanshan, et al.
(författare)
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A film-like SERS aptasensor for sensitive detection of patulin based on GO@Au nanosheets
- 2024
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Ingår i: Food Chemistry. - : Elsevier. - 0308-8146 .- 1873-7072. ; 441
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Tidskriftsartikel (refereegranskat)abstract
- Patulin (PAT) commonly contaminates fruits, posing a significant risk to human health. Therefore, a highly effective and sensitive approach in identifying PAT is warranted. Herein, a SERS aptasensor was constructed based on a two-dimensional film -like structure. GO@Au nanosheets modified with SH-cDNA were employed as capture probes, while core -shell Au@Ag nanoparticles modified with 4 -MBA and SH-Apt were utilized as signal probes. Through the interaction between capture probes and signal probes, adjustable hotspots were formed, yielding a significant Raman signal. During sensing, the GO@Au-cDNA competitively attached to Au@AgNPs@MBA-Apt, resulting in an inverse relationship between PAT levels and SERS intensity. The acquired results exhibited linear responses to PAT within the range of 1-70 ng/mL, with a calculated limit of detection of 0.46 ng/mL. In addition, the SERS aptasensor exhibited satisfactory recoveries in apple samples, which aligned closely with HPLC. With high sensitivity and specificity, this method holds significant potential for PAT detection.
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| 23. |
- Yu, Donggang, et al.
(författare)
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Detection and Analysis of Cell Nuclear Phases
- 2008
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Ingår i: Knowledge-Based Intelligent Information and Engineering Systems. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783540855620 - 9783540855637 ; , s. 401-408
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Bokkapitel (refereegranskat)abstract
- Automated analysis of molecular images has increasingly become an important research in computational life science. In this paper some new and efficient algorithms for detecting and analyzing cell phases of high-content screening are presented. The conceptual frameworks are based on the morphological features of cell nuclei. Furthermore, the novel detecting and analyzing strategies of feed-forward and feed-back of cell phases are proposed based on grey feature, cell shape, geometrical features and difference information of corresponding neighbor frames. Experiment results tested the efficiency of the new method.
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| 24. |
- Yu, Donggang, et al.
(författare)
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Recognition and analysis of cell nuclear phases for high-content screening based on morphological features
- 2009
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Ingår i: NOVA. The University of Newcastle’s Digital Repository. - : Elsevier BV. - 0031-3203. ; 42:4, s. 498-508
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Tidskriftsartikel (refereegranskat)abstract
- Automated analysis of molecular images has increasingly become an important research in computational life science. In this paper some new and efficient algorithms for recognizing and analyzing cell phases of high-content screening are presented. The conceptual frameworks are based on the morphological features of cell nuclei. The useful preprocessing includes: smooth following and linearization; extraction of morphological structural points; shape recognition based morphological structure; issue of touching cells for cell separation and reconstruction. Furthermore, the novel detecting and analyzing strategies of feed-forward and feed-back of cell phases are proposed based on gray feature, cell shape, geometrical features and difference information of corresponding neighbor frames. Experiment results tested the efficiency of the new method.
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| 25. |
- Zhou, M. F., et al.
(författare)
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A recurrent neural network based microscopic car following model to predict traffic oscillation
- 2017
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Ingår i: Transportation Research, Part C: Emerging Technologies. - : Elsevier BV. - 0968-090X. ; 84, s. 245-264
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a recurrent neural network based microscopic car following model that is able to accurately capture and predict traffic oscillation. Neural network models have gained increasing popularity in many fields and have been applied in modelling microscopic traffic flow dynamics due to their parameter-free and data-driven nature. We investigate the existing neural network based microscopic car following models, and find out that they are generally accurate in predicting traffic flow dynamics under normal traffic operational conditions. However, they do not maintain accuracy under conditions of traffic oscillation. To bridge this research gap, we first propose four neural network based models and evaluate their applicability to predict traffic oscillation. It is found that, with an appropriate structure and objective function, the recurrent neural network based model has the capability of perfectly re-establishing traffic oscillations and distinguish drivers characteristics. We further compare the proposed model with a classical car following model (Intelligent Driver Model). Based on our case study, the proposed model outperforms the classical car following model in predicting traffic oscillations with different driver characteristics.
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| 26. |
- Zhou, M. F., et al.
(författare)
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Development of an Efficient Driving Strategy for Connected and Automated Vehicles at Signalized Intersections: A Reinforcement Learning Approach
- 2020
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Ingår i: IEEE Transactions on Intelligent Transportation Systems. - 1524-9050 .- 1558-0016. ; 21:1, s. 433-443
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Tidskriftsartikel (refereegranskat)abstract
- The concept of Connected and Automated Vehicles (CAVs) enables instant traffic information to be shared among vehicle networks. With this newly proposed concept, a vehicle's driving behaviour will no longer be solely based on the driver's limited and incomplete observation. By taking advantages of the shared information, driving behaviours of CAVs can be improved greatly to a more responsible, accurate and efficient level. This study proposed a reinforcement-learning-based car following model for CAVs in order to obtain an appropriate driving behaviour to improve travel efficiency, fuel consumption and safety at signalized intersections in real-time. The result shows that by specifying an effective reward function, a controller can be learned and works well under different traffic demands as well as traffic light cycles with different durations. This study reveals a great potential of emerging reinforcement learning technologies in transport research and applications.
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| 27. |
- Zhou, Mofan, et al.
(författare)
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Improving efficiency at highway T-junctions with connected and automated vehicles
- 2021
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Ingår i: Transportmetrica A: Transport Science. - : Informa UK Limited. - 2324-9943 .- 2324-9935. ; 17:1, s. 107-123
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Tidskriftsartikel (refereegranskat)abstract
- Hong Kong Society for Transportation Studies Limited. The development in communication technologies offers efficient vehicular communication capability. Vehicles in communication with road infrastructure share essential traffic information that can be used to develop cooperative driving strategies. In this paper, we aim to propose a heuristic and cooperative method to improve efficiency and merging capacity for highway T-junctions. We evaluated a few performance indicators including travel time, safety and emission. Results indicate that a significant improvement is observed in comparison with the baseline benchmarking case. We further conducted simulations with different geometric configurations and pointed out a few issues that need to be addressed in order to maximise the benefit.
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| 28. |
- Zhou, Mofan, et al.
(författare)
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On the impact of cooperative autonomous vehicles in improving freeway merging: A modified intelligent driver model based approach
- 2017
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Ingår i: IEEE Transactions on Intelligent Transportation Systems. - 1524-9050 .- 1558-0016. ; 18:6, s. 1422-1428
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Tidskriftsartikel (refereegranskat)abstract
- Transport researchers and practitioners have long been seeking capable solutions to deal with the traffic oscillations caused by freeway merging. Although existing approaches based on ramp metering have improved the overall efficiency of on-ramps, their performance is still far below the theoretical capacity. The recently proposed detecting technology of autonomous vehicles (AVs) provides an alternative for maximizing the merging efficiency by developing and using appropriate controllers for AVs. In this paper, we develop a cooperative intelligent driver model in order to examine the system performance under different proportions of AVs. The results show that, with a proper vehicle-to-vehicle controlling mechanism, an increasing percentage of AVs will reduce the total travel time and smooth traffic oscillations.
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