22 results on '"Lijun Lu"'
Search Results
2. Relative compatibility of Schistosoma mansoni with and Biomphalaria sudanica B. pfeifferi from Kenya as assessed by PCR amplification of the gene S. mansoni ND5 in conjunction with traditional methods.
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Lijun Lu, Si-Ming Zhang, Mutuku, Martin W., Mkoji, Gerald M., and Loker, Eric S.
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SCHISTOSOMA mansoni , *BIOMPHALARIA , *HOST-parasite relationships , *POLYMERASE chain reaction , *GENE amplification - Abstract
Background: Schistosoma mansoni is hosted by several species of Biomphalaria spp. snails in Africa. We were interested in determining if there were differences in compatibility of S. mansoni with Biomphalaria sudanica from Lake Victoria, or with B. pfeifferi from streams and smaller water bodies in Kenya. Does this parasite develop with equal efficiency in both snail species, and does this have implications for transmission in different habitat types? Methods: Primers for PCR amplification of the S. mansoni ND5 gene were designed and tested for sensitivity and specificity. We exposed laboratory-reared B. sudanica and field-derived B. pfeifferi to single miracidium infections and at 1, 2, 4, 8, 16 and 24 days post-exposure (dpe), snails were extracted for the PCR assay. Snails were also shed for cercariae and/or dissected prior to extraction. Additionally, B. sudanica and B. pfeifferi were collected from field locations and tested with the PCR assay. Results: The ND5 PCR assay was sensitive (>0.1 fg S. mansoni genomic DNA) and allowed S. mansoni to be differentiated from other relevant schistosome species or snails. The number of PCR positive snails at 1-4 dpe was higher for B. pfeifferi than for B. sudanica, but not significantly so (P = 0.052). From 8-24 dpe, more B. pfeifferi harbored successfully developing parasites (positive by both dissection and PCR) than did B. sudanica (P = 0.008). At 40 dpe, more B. pfeifferi than B. sudanica shed cercariae or harbored dissection positive/PCR positive infections (P < 0.001). Both immature and failed (dissection negative but PCR positive) S. mansoni infections could also be detected in naturally infected snails of both species. Conclusions: The PCR assay detected S. mansoni infections in snails exposed to one miracidium for one day. Both B. sudanica and B. pfeifferi supported full development of S. mansoni,b u t B. pfeifferi was more compatible, with significantly more dissection positive/PCR positive or shedding infections, and significantly fewer failed infections (dissection negative/PCR positive). This highlights the relatively lower compatibility of B. sudanica with S. mansoni,a n d suggests the factors responsible for incompatibility and how they might affect transmission of S. mansoni in habitats like Lake Victoria deserve additional study. [ABSTRACT FROM AUTHOR]
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- 2016
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3. Woodland Extraction from High-Resolution CASMSAR Data Based on Dempster-Shafer Evidence Theory Fusion.
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Lijun Lu, Wenjun Xie, Jixian Zhang, Guoman Huang, Qiwei Li, and Zheng Zhao
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FORESTS & forestry , *DEMPSTER-Shafer theory , *SYNTHETIC aperture radar , *LAND cover , *IMAGE segmentation , *VEGETATION mapping , *VEGETATION monitoring - Abstract
Mapping and monitoring of woodland resources is necessary, since woodland is vital for the natural environment and human survival. The intent of this paper is to propose a fusion scheme for woodland extraction with different frequency (P- and X-band) polarimetric synthetic aperture radar (PolSAR) and interferometric SAR (InSAR) data. In the study area of Hanjietou, China, a supervised complex Wishart classifier based on the initial polarimetric feature analysis was first applied to the PolSAR data and achieved an overall accuracy of 88%. An unsupervised classification based on elevation threshold segmentation was then applied to the InSAR data, with an overall accuracy of 90%. After Dempster-Shafer (D-S) evidence theory fusion processing for the PolSAR and InSAR classification results, the overall accuracy of fusion result reached 95%. It was found the proposed fusion method facilitates the reduction of polarimetric and interferometric SAR classification errors, and is suitable for the extraction of large areas of land cover with a uniform texture and height. The woodland extraction accuracy of the study area was sufficiently high (producer's accuracy of 96% and user's accuracy of 96%) enough that the woodland map generated from the fusion result can meet the demands of forest resource mapping and monitoring. [ABSTRACT FROM AUTHOR]
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- 2015
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4. LIQUID-DIAPHRAGM INTERACTION OF MICROPUMP.
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Jiankang Wu and Lijun Lu
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PIEZOELECTRIC devices , *FLUIDS , *SILICON , *COUPLED mode theory (Wave-motion) , *LIQUIDS , *EQUATIONS , *NUMERICAL solutions to equations - Abstract
This paper employs a thickness-averaged shallow water model to approximate periodical flows in a piezoelectric micropump. The fluid pressure equation is combined with the vibration equation of silicon diaphragm to construct a liquid-solid coupled equation. Numerical results of mode analysis of the coupled system indicate that the natural frequencies of coupled system are much lower than those of the non-coupled system. The relationships of the first order amplitude-frequency of the silicon diaphragm, and the flow rate-frequency of micropump are also given in this paper. [ABSTRACT FROM AUTHOR]
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- 2005
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5. Raytracing facility for soft x-ray and vacuum ultraviolet monochromators at NSRL.
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Lijun, Lu
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MONOCHROMATORS , *SPECTRUM analysis instruments - Abstract
A raytracing facility for evaluating soft x-ray and vacuum ultraviolet optics, especially synchrotron radiation monochromators and beamlines, has been reported. Such kinds of optics consist of any number of reflecting mirrors, gratings, and, if needed, stop apertures: in coplanar or orthogonal configuration; conventional, holographic, and varied line-space gratings are available dispersing elements in design of a monochromator. Both normal and grazing incidence optics Can be handled well. Point or finite sources, necessary to be setup in the raytracing process, may be used of isotropic or of Gaussian distribution. The spot diagram or grey level image simulation will be produced. Finally, an example of its applications, raytracing of a Seya-Namioka monochromator beamline at NSRL, will be presented. [ABSTRACT FROM AUTHOR]
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- 1994
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6. Anatomy-guided brain PET imaging incorporating a joint prior model.
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Lijun Lu, Jianhua Ma, Qianjin Feng, Wufan Chen, and Arman Rahmim
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BRAIN imaging , *POSITRON emission tomography , *BRAIN anatomy , *IMAGE reconstruction , *HIGH resolution imaging , *A posteriori error analysis - Abstract
We proposed a maximum a posterior (MAP) framework for incorporating information from co-registered anatomical images into PET image reconstruction through a novel anato-functional joint prior. The characteristic of the utilized hyperbolic potential function is determinate by the voxel intensity differences within the anatomical image, while the penalization is computed based on voxel intensity differences in reconstructed PET images. Using realistic simulated 18FDG PET scan data, we optimized the performance of the proposed MAP reconstruction with the joint prior (JP-MAP) and compared its performance with conventional 3D MLEM and 3D MAP reconstructions. The proposed JP-MAP reconstruction algorithm resulted in quantitatively enhanced reconstructed images, as demonstrated in extensive FDG PET simulation study. The proposed method was also tested on a 20 min Florbetapir patient study performed on the high-resolution research tomograph. It was shown to outperform conventional methods in visual as well as quantitative accuracy assessment (in terms of regional noise versus activity value performance). The JP-MAP method was also compared with another MR-guided MAP reconstruction method, utilizing the Bowsher prior and was seen to result in some quantitative enhancements, especially in the case of MR-PET mis-registrations, and a definitive improvement in computational performance. [ABSTRACT FROM AUTHOR]
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- 2015
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7. Prognostic generalization of multi-level CT-dose fusion dosiomics from primary tumor and lymph node in nasopharyngeal carcinoma.
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Chunya Cai, Wenbing Lv, Feng Chi, Bailin Zhang, Lin Zhu, Geng Yang, Shiwu Zhao, Yuanhu Zhu, Xu Han, Zhenhui Dai, Xuetao Wang, and Lijun Lu
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NASOPHARYNX cancer , *LYMPH nodes , *IMAGE fusion , *COMPUTED tomography , *GENERALIZATION , *LOG-rank test , *NO-tillage - Abstract
Purpose: To investigate the prognostic performance of multi-level computed tomography (CT)-dose fusion dosiomics at the image-, matrix-, and featurelevels from the gross tumor volume (GTV) at nasopharynx and the involved lymph node for nasopharyngeal carcinoma (NPC) patients. Methods: Two hundred and nineteen NPC patients (175 vs. 44 for training vs. internal validation) were used to train prediction model, and 32 NPC patients were used for external validation. We first extracted CT and dose information from intratumoral nasopharynx (GTV_nx) and lymph node (GTV_nd) regions. Then, the corresponding peritumoral regions (RING_3 mm and RING_5 mm) were also considered. Thus, the individual and combination of intratumoral and peritumoral regions were as follows: GTV_nx, GTV_nd, RING_3 mm_nx, RING_3 mm_nd, RING_5 mm_nx, RING_5 mm_nd, GTV_nxnd, RING_3 mm_nxnd, RING_5 mm_nxnd, GTV + RING_3 mm_nxnd, and GTV + RING_5 mm_nxnd. For each region, 11 models were built by combining five clinical parameters and 127 features from: (1) dose images alone; (2-7) fused dose and CT images via wavelet-based fusion using CT weights of 0.2, 0.4, 0.6, and 0.8, gradient transfer fusion, and guided-filtering-based fusion (GFF); (8) fused matrices (sumMat); (9-10) fused features derived via feature averaging (avgFea) and feature concatenation (conFea); and finally, (11) CT images alone. The concordance index (C-index) and Kaplan-Meier curves with log-rank test were used to assess model performance. Results: The fusion models'performance was better than single CT/dose model on both internal and external validation. Models that combined the information from both GTV_nx and GTV_nd regions outperformed the single region model. For internal validation, GTV + RING_3 mm_nxnd GFF model achieved the highest C-index both in recurrence-free survival (RFS) and metastasis-free survival (MFS) predictions (RFS: 0.822; MFS: 0.786). The highest C-index in external validation set was achieved by RING_3 mm_nxnd model (RFS: 0.762; MFS: 0.719). The GTV + RING_3 mm_nxnd GFF model is able to significantly separate patients into high-risk and low-risk groups compared to dose-only or CT-only models. Conclusion: Fusion dosiomicsmodel combining the primary tumor, the involved lymph node, and 3 mm peritumoral information outperformed single-modality models for different outcome predictions, which is helpful for clinical decisionmaking and the development of personalized treatment. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Insights into the Evolution of an Emulsion with Demulsifying Bacteria Based on Turbiscan.
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Kaiming Peng, Xuhui Wang, Lijun Lu, Jia Liu, Xiupeng Guan, and Xiangfeng Huang
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EMULSIONS , *BACTERIA , *DEMULSIFICATION , *FLOCCULATION , *VELOCITY - Abstract
In this study, the demulsification process of four demulsifying bacteria was analyzed in situ using a newly developed method based on backscattering data from Turbiscan. First, the distribution difference of backscattering was employed to divide the entire demulsification process. Second, the Mie theory and the first order differential of the backscattering intensity along emulsion height were introduced to track emulsion variation over time. The demulsification process was divided into three stages. Consumption time, changing degree, and changing velocity during each stage varied depending on the type of bacteria. The flocculation and coalescence of water drops in the initial stage contributed substantially to the final demulsification efficiency. This study provides a powerful tool for understanding the evolution of emulsions in response to the action of various demulsifiers. [ABSTRACT FROM AUTHOR]
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- 2016
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9. Carbon Source Dependence of Cell Surface Composition and Demulsifying Capability of Alcaligenes sp. S-XJ-1.
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Xiangfeng Huang, Kaiming Peng, Lijun Lu, Ruofei Wang, and Jia Liu
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CELL membranes , *DEMULSIFICATION , *CARBON , *EMULSIONS , *ALCALIGENES - Abstract
Biodemulsifiers are environmentally friendly agents used in recycling oil or purifying water from emulsion, yet the demulsifying feature of cell-surface composition remains unclear. In this study, potentiometric titration, attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry were combined to characterize cell-surface chemical composition of demulsifying strain Alcaligenes sp. S-XJ-1 cultivated with different carbon sources. Cells cultivated with alkane contained abundant elemental nitrogen and basic functional groups, indicating that their surface was rich in proteins or peptides, which contributed to their highest demulsifying efficiency. For cells cultivated with fatty acid ester, the relatively abundant surface lipid contributed to a 50% demulsification ratio owing to the presence of more acidic functional group. The cells cultivated with glucose exhibited a high oxygen concentration (O/C ~0.28), which indicated the presence of more polysaccharides on the cell surface. This induced the lowest demulsification ratio of 30%. It can be concluded that cell surface-associated proteins or lipids other than the polysaccharide of the demulsifying strain played a positive role in the demulsification activity. In addition, the cell-surface oligoglutamate compounds identified in situ were crucial to the demulsifying capability. [ABSTRACT FROM AUTHOR]
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- 2014
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10. Self-adaptive cardiac optogenetics device based on negative stretching-resistive strain sensor.
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Wen Hong, Chunpeng Jiang, Mu Qin, Ziliang Song, Pengfei Ji, Longchun Wang, Kejun Tu, Lijun Lu, Zhejun Guo, Bin Yang, Xiaolin Wang, and Jingquan Liu
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STRAIN sensors , *RUBBER , *OPTOGENETICS , *WRINKLE patterns , *LASER beam cutting , *SHAPE memory effect - Abstract
The article presents a study that explores the self-adaptive cardiac optogenetics device based on negative stretching-resistive strain sensor. It demonstrates the potential of a negative stretching-resistive device in controlling-in-sensor electronics for wearable/ implantable autodiagnosis and telehealth applications.
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- 2021
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11. The Repertoire and Evolution of ATP-Binding Cassette Systems in Synechococcus and Prochlorococcus.
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Lijing Bu, Jian Xiao, Lijun Lu, Gang Xu, Jinsong Li, Fangqing Zhao, Xiaokun Li, and Jinyu Wu
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ADENOSINE triphosphate , *PHYLOGENY , *PROTEINS , *METABOLISM , *BIOMASS , *COMPARATIVE studies - Abstract
Synechococcus and Prochlorococcus have made great contributions to earth’s photosynthetic biomass. ATP-binding cassette (ABC) protein systems have been characterized to play important roles in various physiological functions, including carbon fixation, phosphate assimilation, and vitamin B12 metabolism. In this study, the repertoire and domain architectures of ABC systems in Synechococcus and Prochlorococcus, as well as their potential evolutionary mechanism, have been surveyed extensively. Comparative analysis revealed an uneven phylogenetic distribution of the ABC systems in these organisms, and in particular that fresh-water Synechococcus strains contain more ABC systems than those of marine ones. Phylogenetic analysis indicated that lineage-specific gene expansion and duplication may be the important forces driving the variability of ABC systems in fresh-water Synechococcus and such an expansion was likely to be relevant to their ecological tolerance. At the domain level, ATP-binding domains in several ABC systems were found to fuse with many additional domains after the divergence from their common ancestor, indicating the versatile functions of ABC systems in cyanobacteria. Subsequently, 19 ABC system families were deduced to be the core set of ABC systems conserved in all marine-living Synechococcus and Prochlorococcus. In conclusion, the comprehensive survey of ABC systems in Synechococcus and Prochlorococcus provides novel insights into their potential evolutionary mechanism and the basis for further investigation of their physiological roles. [ABSTRACT FROM AUTHOR]
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- 2009
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12. Reconstruction of DEMs From ERS-⅛ Tandem Data in Mountainous Area Facilitated by SRTM Data.
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Mingsheng Liao, Teng Wang, Lijun Lu, Wenjun Zhou, and Deren Li
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SYNTHETIC aperture radar , *RADAR , *INTERFEROMETRY , *INTERPOLATION , *REGRESSION analysis , *ALGORITHMS - Abstract
A new approach is presented in this paper to produce Digital Elevation Model (DEM) in mountainous areas with steep slope using ERS-½ tandem data. In order to reduce the impact of phase errors on the Interferometric Synthetic Aperture Radar (InSAR)-generated DEM, an external DEM such as that from Shuttle Radar Topography Mission (SRTM) is utilized in this approach. The proposed algorithm includes two steps: The first step is to model and remove phase trends with a linear regression analysis before converting phase to height; the second step is to filter unreliable height points before interpolating the DEM from the InSAR height map. The critical points are the following: 1) determining the one-to-one correspondence between the interferogram and the SRTM DEM before knowing the InSAR-derived elevation values and 2) estimating the elevation range of every pixel from SRTM DEM. To solve the first problem, an iteratively geocoding algorithm is performed. A DEM interpolation error model solves the second one. For InSAR data processing, the SRTM DEM is not only usable for modeling systematic phase errors but also for filtering gross height errors. The experiments in Zhangbei and the Three Gorges areas in China show that our approach has improved the accuracy of the resulting DEMs significantly without any ground control points. [ABSTRACT FROM AUTHOR]
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- 2007
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13. Sex-Dependent Effects of Cadmium Exposure in Early Life on Gut Microbiota and Fat Accumulation in Mice.
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Mian Li, Peizhan Chen, Chao Huang, Lijun Lu, Qian Ba, Jingquan Li, Ruiai Chu, DongXie, Haiyun Song, Hao Ying, Hui Wang, Yongning Wu, Xudong Jia, and Xiaohua Duan
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LIPID metabolism , *FECAL microbiota transplantation , *DNA analysis , *LIVER analysis , *ADIPOSE tissues , *ANALYSIS of variance , *ANIMAL experimentation , *BIOLOGICAL models , *HUMAN body composition , *CADMIUM , *ENZYME-linked immunosorbent assay , *MICE , *PROBABILITY theory , *RESEARCH funding , *T-test (Statistics) , *TIME series analysis , *ENVIRONMENTAL exposure , *GUT microbiome , *DATA analysis software , *GENE expression profiling , *DESCRIPTIVE statistics , *SEQUENCE analysis , *MANN Whitney U Test , *KRUSKAL-Wallis Test - Abstract
BACKGROUND: Environmental cadmium, with a high average dietary intake, is a severe public health risk. However, the long-term health implications of environmental exposure to cadmium in different life stages remain unclear. OBJECTIVES: We investigated the effects of early exposure to cadmium, at an environmentally relevant dosage, on adult metabolism and the mechanism of action. METHODS: We established mouse models with low-dose cadmium (LDC) exposure in early life to examine the long-term metabolic consequences. Intestinal flora measurement by 16S rDNA sequencing, microbial ecological analyses, and fecal microbiota transplant was conducted to explore the potential underlying mechanisms. RESULTS: Early LDC exposure (100 nM) led to fat accumulation in adult male mice. Hepatic genes profiling revealed that fatty acid and lipid metabolic processes were elevated. Gut microbiota were perturbed by LDC to cause diversity reduction and compositional alteration. Time-series studies indicated that the gut flora at early-life stages, especially at 8 weeks, were vulnerable to LDC and that an alteration during this period could contribute to the adult adiposity, even if the microbiota recovered later. The importance of intestinal bacteria in LDC-induced fat accumulation was further confirmed through microbiota transplantation and removal experiments. Moreover, the metabolic effects of LDC were observed only in male, but not female, mice. CONCLUSIONS: An environmental dose of cadmium at early stages of life causes gut microbiota alterations, accelerates hepatic lipid metabolism, and leads to life-long metabolic consequences in a sex-dependent manner. These findings provide a better understanding of the health risk of cadmium in the environment. CITATION: Ba Q, Li M, Chen P, Huang C, Duan X, Lu L, Li J, Chu R, Xie D, Song H, Wu Y, Ying H, Jia X, Wang H. 2017. Sex-dependent effects of cadmium exposure in early life on gut microbiota and fat accumulation in mice. Environ Health Perspect 125:437-446; http://dx.doi. org/10.1289/EHP360 [ABSTRACT FROM AUTHOR]
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- 2017
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14. Alkaline fermentation of waste activated sludge stimulated by saponin: volatile fatty acid production, mechanisms and pilot-scale application.
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Xiangfeng Huang, Tianshuai Mu, Changming Shen, Lijun Lu, and Jia Liu
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FERMENTATION , *SEWAGE purification , *LEAVENING agents , *SOURDOUGH starter , *FATTY acids , *BUTYRIC acid - Abstract
Volatile fatty acid (VFA) production stimulated by saponin (SP), an environmentally friendly bio-surfactant, was investigated during sludge alkaline fermentation in laboratory studies and pilot applications. The combined use of SP and pH 9 condition significantly enhanced VFA production to approximately 425 mg COD/g VSS, which was 4.7-fold of raw sludge and 1.5-fold of sole pH 10 adjustment (the optimum pH for alkaline fermentation). Further results indicated that SP & pH 9 condition provided sufficient substrates for acidification and decreased the consumption of VFAs through methanogenesis. Moreover, SP accompanied by moderate alkaline condition (i.e. pH 9) showed weaker inhibitory effects on key enzyme activities and metabolic potential of acidification microorganisms than sole pH 10 adjustment. On this basis, a pilot-scale system involving anaerobic fermentation and anaerobic-anoxic-aerobic step-feed bioreaction tanks was established to study the potential of VFAs as supplementary carbon sources for wastewater treatment. The influent of the pilot system was sanitary wastewater characterized by low C/N ratios from a scenic rural area. After flocculation and nutrient precipitation, the fermentation supernatant was mixed with the influent at a volume ratio of 1:30. With this approach, nitrogen and phosphorus concentrations in effluent fulfilled the first-A wastewater discharge standard in China. [ABSTRACT FROM AUTHOR]
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- 2016
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15. Robust low-dose dynamic cerebral perfusion CT image restoration via coupled dictionary learning scheme.
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Xiumei Tian, Dong Zeng, Shanli Zhang, Jing Huang, Hua Zhang, Ji He, Lijun Lu, Weiwen Xi, Jianhua Ma, and Zhaoying Bian
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PERFUSION , *COMPUTED tomography , *X-rays , *IMAGE reconstruction , *CEREBROVASCULAR disease - Abstract
Dynamic cerebral perfusion x-ray computed tomography (PCT) imaging has been advocated to quantitatively and qualitatively assess hemodynamic parameters in the diagnosis of acute stroke or chronic cerebrovascular diseases. However, the associated radiation dose is a significant concern to patients due to its dynamic scan protocol. To address this issue, in this paper we propose an image restoration method by utilizing coupled dictionary learning (CDL) scheme to yield clinically acceptable PCT images with low-dose data acquisition. Specifically, in the present CDL scheme, the 2D background information from the average of the baseline time frames of low-dose unenhanced CT images and the 3D enhancement information from normal-dose sequential cerebral PCT images are exploited to train the dictionary atoms respectively. After getting the two trained dictionaries, we couple them to represent the desired PCT images as spatio-temporal prior in objective function construction. Finally, the low-dose dynamic cerebral PCT images are restored by using a general DL image processing. To get a robust solution, the objective function is solved by using a modified dictionary learning based image restoration algorithm. The experimental results on clinical data show that the present method can yield more accurate kinetic enhanced details and diagnostic hemodynamic parameter maps than the state-of-the-art methods. [ABSTRACT FROM AUTHOR]
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- 2016
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16. Dynamic positron emission tomography restoration with low-rank representation incorporating edge preservation.
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Yuanyuan Gao, Zhaoying Bian, Benfu Li, Jie Peng, Lijun Lu, Jianhua Ma, and Wufan Chen
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POSITRON emission tomography , *SIGNAL-to-noise ratio , *DIGITAL image processing , *GAUSSIAN distribution , *SPATIAL analysis (Statistics) - Abstract
BACKGROUND: Dynamic positron emission tomography (PET) is a powerful tool that provides useful quantitative information on physiological and biochemical processes. However, the low signal-to-noise ratio (SNR) in short dynamic frames is a challenge. OBJECTIVE: To get high SNR in the dynamic PET and to achieve high-quality PET parametric image are the objective of this study. METHODS: Low-rank (LR) modeling and edge-preserving prior are incorporated in this study with a unified mathematical framework to improve the SNR of a dynamic PET image series. The proposed algorithm is designed to reduce noise in homogeneous areas while preserving the edges of regions of interest. RESULTS: The performance of the proposed method (LRH) is compared both visually and quantitatively by using the classic Gaussian filter and an LR expression filter on a digital brain phantom and in vivo rat study. Experimental results demonstrate that the proposed filter can achieve superior visual and quantitative performance without sacrificing spatial resolution. CONCLUSIONS: The proposed LRH is considerably effective and exhibits great potential in processing dynamic PET data with high noise levels. [ABSTRACT FROM AUTHOR]
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- 2016
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17. Novel application of bamboo-based fibers in a biological contact oxidation process.
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Xiaoming Zou, Yi Feng, Changming Sheng, Jia Liu, Lijun Lu, Cui Hu, and Xiangfeng Huang
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OXIDATION , *INDUSTRIAL wastes , *CHARCOAL , *NONMETALS , *SEWAGE purification - Abstract
Generally, biofilm-supporting carriers in biological contact oxidation processes are made from thermoplastic polymers, which cause potential ecological damage because of the low biodegradation and high accumulation in organisms. Thus, four bamboo-based fibers, bamboo primitive fiber, bamboo fiber, bamboo charcoal fiber (BBF) and bamboo charcoal-cotton blending fiber (BCBF), were used as carriers and compared with two commercial carriers (vinylon (VY) and polypropylene (PP)) in a biological contact oxidation process system with the goal to develop a biodegradable and sustainable biofilm medium. Under steady state conditions, pollutants (chemical oxygen demand and NH4+-N) in stage 1 (days 1-29, hydraulic retention time (HRT)= 12 h) were efficiently removed with a removal efficiency ranging from 85 to 95%. In stage 2 (days 30-53, HRT = 4-12 h), the pollutant-removal efficiency of four reactors (BBF, BCBF, VY and PP) were nearly indistinguishable and were higher than the two other reactors, especially when the HRT was set at 4 h (days 46-53). Consequently, two optimized bamboo-based fibers (BBF and BCBF) can be developed as biofilm carriers for wastewater treatment in the future. Furthermore, studies demonstrated that the biofilm development difference showed good correlation with their specific area and relative oxygen content but not with their tenacity and antimicrobial activity. [ABSTRACT FROM AUTHOR]
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- 2014
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18. Direct 4D parametric imaging for linearized models of reversibly binding PET tracers using generalized AB-EM reconstruction.
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Rahmim, Arman, Yun Zhou, Jing Tang, Lijun Lu, Sossi, Vesna, and Wong, Dean F.
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IMAGING systems , *RADIOACTIVE tracers , *POSITRON emission tomography , *IMAGE reconstruction , *BRAIN imaging , *ALGORITHMS , *PARAMETER estimation - Abstract
Due to high noise levels in the voxel kinetics, development of reliable parametric imaging algorithms remains one of most active areas in dynamic brain PET imaging, which in the vast majority of cases involves receptor/transporter studies with reversibly binding tracers. As such, the focus of this work has been to develop a novel direct 4D parametric image reconstruction scheme for such tracers. Based on a relative equilibrium (RE) graphical analysis formulation (Zhou et al 2009b Neuroimage 44 661-70), we developed a closed-form 4D EM algorithm to directly reconstruct distribution volume (DV) parametric images within a plasma input model, as well as DV ratio (DVR) images within a reference tissue model scheme (wherein an initial reconstruction was used to estimate the reference tissue time-activity curves). A particular challenge with the direct 4D EM formulation is that the intercept parameters in graphical (linearized) analysis of reversible tracers (e.g. Logan or RE analysis) are commonly negative (unlike for irreversible tracers, e.g. using Patlak analysis). Subsequently, we focused our attention on the AB-EM algorithm, derived by Byrne (1998, Inverse Problems 14 1455- 67) to allow inclusion of prior information about the lower (A) and upper (B) bounds for image values. We then generalized this algorithm to the 4D EM framework, thus allowing negative intercept parameters. Furthermore, our 4D AB-EM algorithm incorporated and emphasized the use of spatially varying lower bounds to achieve enhanced performance. As validation, the means of parameters estimated from 55 human 11C-raclopride dynamic PET studies were used for extensive simulations using a mathematical brain phantom. Images were reconstructed using conventional indirect as well as proposed direct parametric imaging methods. Noise versus bias quantitative measurements were performed in various regions of the brain. Direct 4D EM reconstruction resulted in notable qualitative and quantitative accuracy improvements (over 35% noise reduction, with matched bias, in both plasma and reference-tissue input models). Similar improvements were also observed in the coefficient of variation of the estimated DV and DVR values even for relatively low uptake cortical regions, suggesting the enhanced ability for robust parameter estimation. Themethodwas also tested on a 90 min 11C-raclopride patient study performed on the high-resolution research tomograph wherein the proposed method was shown across a variety of regions to outperform the conventional method in the sense that for a given DVR value, improved noise levels were observed. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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19. Thermodynamics and Kinetics of p-Aminophenol Adsorption on Poly(aryl ether ketone) Containing Pendant Carboxyl Groups.
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Xiqian Li, Xiao Zhou, Jun Mu, Lijun Lu, Dachuan Han, Chunmei Lu, and Mingtai Wang
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PHENOL , *POLYARYLETHERS , *THERMODYNAMICS , *CARBOXYLIC acids , *ADSORPTION (Chemistry) , *CHEMICAL kinetics , *PH effect , *FREUNDLICH isotherm equation - Abstract
We have studied the adsorption of p-aminophenol on poly(aryl ether ketone) containing pendant carboxyl groups (PEK-L). The pH effect, adsorption kinetics, isotherms, and thermodynamics are investigated in batch experiments. The kinetics of the adsorption follows a pseudosecond-order model. Langmuir and Freundlich isotherms are employed to describe the adsorption process, indicating that the former fits the data better. The thermodynamic functions, ÎG°, ÎH°, and ÎS°are calculated. The method is applied to the determination of p-aminophenol in drug tablet samples, and the accuracy is assessed through recovery experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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20. Photosynthetic metabolism of C[sub3] plants shows highly cooperative regulation under changing environments: A systems biological analysis.
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Ruoyu Luo, Haibin Wei, Lin Ye, Kankan Wang, Fan Chen, Lijun Lu, Lei Liu, Yuanyuan Li, Crabbe, M. James C., Li Jin, Yixue Li, and Yang Zhong
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PHOTOSYNTHESIS , *PLANT metabolism , *DROUGHTS , *CARBON dioxide & the environment , *CHLOROPLASTS , *ECOLOGICAL disturbances - Abstract
We studied the robustness of photosynthetic metabolism in the chloroplasts of C[sub3] plants under drought stress and at high CO[sub2] concentration conditions by using a method called Minimization of Metabolic Adjustment Dynamic Flux Balance Analysis (MDFBA). Photosynthetic metabolism in the chloroplasts of C3 plants applies highly cooperative regulation to minimize the fluctuation of metabolite concentration profiles in the face of transient perturbations. Our work suggests that highly cooperative regulation assures the robustness of the biological system and that there is closer cooperation under perturbation conditions than under normal conditions. This results in minimizing fluctuations in the profiles of metabolite concentrations, which is the key to maintaining a system's function. Our methods help in understanding such phenomena and the mechanisms of robustness for complex metabolic networks in dynamic processes. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
21. Multiresidue Determination of 77 Pesticides in Textiles by Gas Chromatography–Mass Spectrometry.
- Author
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Xiao Zhou, Mingtai Wang, Zhe Sun, Aijun Li, Liming Xu, Jun Mu, and Lijun Lu
- Subjects
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PESTICIDES , *TEXTILES , *GAS chromatography , *MASS spectrometry - Abstract
A simple and efficient method for multiple determination of 77 pesticides, including one organonitrogen, eight carbamate, 12 pyrethroid, 26 organochloride, 30 organophosphorous compounds, in textiles is developed. Six representative textiles are chosen as test samples. Extraction using hexane–ethyl acetate (1:1) assisted by ultrasonic processor is carried out twice, followed by clean-up using solid-phase extraction on a florisil column. The final solution is analyzed using gas chromatography–mass spectrometry, and 77 pesticides are determined. This method is highly sensitive, selective, and reproducible, with a broad linear range and reliable accuracy. Six blank samples are spiked with 0.50 and 2.00 mg/kg of the 77 pesticides, and the corresponding recoveries are between 64.5% and 99.1%; the precisions range from 4.04% to 14.78%; and the minimum detection limits of this method are 0.02–0.20 mg/kg. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
22. Robust dynamic myocardial perfusion CT deconvolution for accurate residue function estimation via adaptive-weighted tensor total variation regularization: a preclinical study.
- Author
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Dong Zeng, Changfei Gong, Zhaoying Bian, Jing Huang, Xinyu Zhang, Hua Zhang, Lijun Lu, Shanzhou Niu, Zhang Zhang, Zhengrong Liang, Qianjin Feng, Wufan Chen, and Jianhua Ma
- Subjects
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CORONARY disease , *MYOCARDIAL reperfusion , *COMPUTED tomography , *ENHANCED magnetoresistance , *RADIATION , *MAGNETIC resonance imaging - Abstract
Dynamic myocardial perfusion computed tomography (MPCT) is a promising technique for quick diagnosis and risk stratification of coronary artery disease. However, one major drawback of dynamic MPCT imaging is the heavy radiation dose to patients due to its dynamic image acquisition protocol. In this work, to address this issue, we present a robust dynamic MPCT deconvolution algorithm via adaptive-weighted tensor total variation (AwTTV) regularization for accurate residue function estimation with low-mA s data acquisitions. For simplicity, the presented method is termed ‘MPD-AwTTV’. More specifically, the gains of the AwTTV regularization over the original tensor total variation regularization are from the anisotropic edge property of the sequential MPCT images. To minimize the associative objective function we propose an efficient iterative optimization strategy with fast convergence rate in the framework of an iterative shrinkage/thresholding algorithm. We validate and evaluate the presented algorithm using both digital XCAT phantom and preclinical porcine data. The preliminary experimental results have demonstrated that the presented MPD-AwTTV deconvolution algorithm can achieve remarkable gains in noise-induced artifact suppression, edge detail preservation, and accurate flow-scaled residue function and MPHM estimation as compared with the other existing deconvolution algorithms in digital phantom studies, and similar gains can be obtained in the porcine data experiment. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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