41 research outputs found
HodgeRank with Information Maximization for Crowdsourced Pairwise Ranking Aggregation
Recently, crowdsourcing has emerged as an effective paradigm for
human-powered large scale problem solving in various domains. However, task
requester usually has a limited amount of budget, thus it is desirable to have
a policy to wisely allocate the budget to achieve better quality. In this
paper, we study the principle of information maximization for active sampling
strategies in the framework of HodgeRank, an approach based on Hodge
Decomposition of pairwise ranking data with multiple workers. The principle
exhibits two scenarios of active sampling: Fisher information maximization that
leads to unsupervised sampling based on a sequential maximization of graph
algebraic connectivity without considering labels; and Bayesian information
maximization that selects samples with the largest information gain from prior
to posterior, which gives a supervised sampling involving the labels collected.
Experiments show that the proposed methods boost the sampling efficiency as
compared to traditional sampling schemes and are thus valuable to practical
crowdsourcing experiments.Comment: Accepted by AAAI201
High-efficient deep learning-based DTI reconstruction with flexible diffusion gradient encoding scheme
Purpose: To develop and evaluate a novel dynamic-convolution-based method
called FlexDTI for high-efficient diffusion tensor reconstruction with flexible
diffusion encoding gradient schemes. Methods: FlexDTI was developed to achieve
high-quality DTI parametric mapping with flexible number and directions of
diffusion encoding gradients. The proposed method used dynamic convolution
kernels to embed diffusion gradient direction information into feature maps of
the corresponding diffusion signal. Besides, our method realized the
generalization of a flexible number of diffusion gradient directions by setting
the maximum number of input channels of the network. The network was trained
and tested using data sets from the Human Connectome Project and a local
hospital. Results from FlexDTI and other advanced tensor parameter estimation
methods were compared. Results: Compared to other methods, FlexDTI successfully
achieves high-quality diffusion tensor-derived variables even if the number and
directions of diffusion encoding gradients are variable. It increases peak
signal-to-noise ratio (PSNR) by about 10 dB on Fractional Anisotropy (FA) and
Mean Diffusivity (MD), compared with the state-of-the-art deep learning method
with flexible diffusion encoding gradient schemes. Conclusion: FlexDTI can well
learn diffusion gradient direction information to achieve generalized DTI
reconstruction with flexible diffusion gradient schemes. Both flexibility and
reconstruction quality can be taken into account in this network.Comment: 11 pages,6 figures,3 table
Phosphoproteins regulated by heat stress in rice leaves
<p>Abstract</p> <p>Background</p> <p>High temperature is a critical abiotic stress that reduces crop yield and quality. Rice (<it>Oryza sativa </it>L.) plants remodel their proteomes in response to high temperature stress. Moreover, phosphorylation is the most common form of protein post-translational modification (PTM). However, the differential expression of phosphoproteins induced by heat in rice remains unexplored.</p> <p>Methods</p> <p>Phosphoprotein in the leaves of rice under heat stress were displayed using two-dimensional electrophoresis (2-DE) and Pro-Q Diamond dye. Differentially expressed phosphoproteins were identified by MALDI-TOF-TOF-MS/MS and confirmed by Western blotting.</p> <p>Results</p> <p>Ten heat-phosphoproteins were identified from twelve protein spots, including ribulose bisphos-phate carboxylase large chain, 2-Cys peroxiredoxin BAS1, putative mRNA binding protein, Os01g0791600 protein, OSJNBa0076N16.12 protein, putative H(+)-transporting ATP synthase, ATP synthase subunit beta and three putative uncharacterized proteins. The identification of ATP synthase subunit beta was further validated by Western-blotting. Four phosphorylation site predictors were also used to predict the phosphorylation sites and the specific kinases for these 10 phosphoproteins.</p> <p>Conclusion</p> <p>Heat stress induced the dephosphorylation of RuBisCo and the phosphorylation of ATP-β, which decreased the activities of RuBisCo and ATP synthase. The observed dephosphorylation of the mRNA binding protein and 2-Cys peroxiredoxin may be involved in the transduction of heat-stress signaling, but the functional importance of other phosphoproteins, such as H<sup>+</sup>-ATPase, remains unknown.</p
Phylogenetic characterization of genes encoding for glycoprotein 5 and membrane protein of PRRSV isolate HH08
A porcine reproductive and respiratory syndrome virus (PRRSV) was obtained from clinic samples. Genes 5 and 6 encoding for the viral glycoprotein 5 and a membrane protein of the PRRSV designated as HH08 were amplified by reverse transcription-PCR. These sequences were compared with reference sequences derived from different geographical locations. The results indicated that the virus belongs to the North American type rather than European. Comparative analyses of the genetic diversity between the PRRSV isolate HH08 and other Chinese as well as foreign reference strains of PRRSV were discussed based on the sequence comparison and the topology of phylogenetic trees constructed in this study
CDK5-dependent BAG3 degradation modulates synaptic protein turnover
阿尔茨海默病(AD)是严重威胁人类健康的重大神经系统疾病,AD的发生发展与衰老密切相关,目前临床治疗方法十分有限。因此迫切需要从AD致病早期入手,发现和鉴定导致AD神经功能紊乱的机制和靶点,为AD的早期防治提供基础。张杰教授及其团队从高通量磷酸化蛋白质组学入手,系统研究了CDK5在神经细胞中的磷酸化底物,鉴定出了在蛋白质量控制中发挥重要功能的BAG3蛋白是CDK5的全新底物。课题组从磷酸化蛋白质组学入手,发现和阐明了细胞周期蛋白激酶5(CDK5)通过调控BAG3在维持突触蛋白水平调控中的作用机制,及其在阿尔茨海默病(AD)发生发展中的机理。
该研究是多个团队历时8年合作完成的,香港中文大学的周熙文教授、美国匹兹堡大学的Karl Herrup教授、美国Sanford-Burnham研究所的许华曦教授、美国梅奥医学中心的卜国军教授,厦门大学医学院的文磊教授、张云武教授、赵颖俊教授、薛茂强教授,军事医学科学院的袁增强教授等都参与了该工作。
厦门大学医学院2012级博士生周杰超等为文章的第一作者,张杰教授为通讯作者。Background
Synaptic protein dyshomeostasis and functional loss is an early invariant feature of
Alzheimer’s disease (AD), yet the unifying etiological pathway remains largely unknown.
Knowing that cyclin-dependent kinase 5 (CDK5) plays critical roles in synaptic formation
and degeneration, its phosphorylation targets were re-examined in search for candidates with
direct global impacts on synaptic protein dynamics, and the associated regulatory network
was also analyzed.
Methods
Quantitative phospho-proteomics and bioinformatics analyses were performed to identify
top-ranked candidates. A series of biochemical assays were used to investigate the associated
regulatory signaling networks. Histological, electrochemical and behavioral assays were
performed in conditional knockout, shRNA-mediated knockdown and AD-related mice
models to evaluate its relevance to synaptic homeostasis and functions.
Results
Among candidates with known implications in synaptic modulations, BCL2-associated
athanogene-3 (BAG3) ranked the highest. CDK5-mediated phosphorylation on
Ser297/Ser291 (Mouse/Human) destabilized BAG3. Loss of BAG3 unleashed the selective
protein degradative function of the HSP70 machinery. In neurons, this resulted in enhanced
degradation of a number of glutamatergic synaptic proteins. Conditional neuronal knockout of
Bag3 in vivo led to impairment of learning and memory functions. In human AD and
related-mouse models, aberrant CDK5-mediated loss of BAG3 yielded similar effects on
synaptic homeostasis. Detrimental effects of BAG3 loss on learning and memory functions
were confirmed in these mice, and such were reversed by ectopic BAG3 re-expression.
Conclusions
Our results highlight that neuronal CDK5-BAG3-HSP70 signaling axis plays a critical
role in modulating synaptic homeostasis. Dysregulation of the signaling pathway directly
contributes to synaptic dysfunction and AD pathogenesis.This work was supported by the National Science Foundation in China (Grant: 31571055, 81522016, 81271421 to J.Z.; 81801337 to L.L; 81774377 and 81373999 to L.W.); Fundamental Research Funds for the Central Universities of China-Xiamen University (Grant: 20720150062, 20720180049 and 20720160075 to J.Z.); Fundamental Research Funds for Fujian Province University Leading Talents (Grant JAT170003 to L.L); Hong Kong Research Grants Council (HKUST12/CRF/13G, GRF660813, GRF16101315, AoE/M-05/12 to K.H.; GRF16103317, GRF16100718 and GRF16100219 to H.-M,C.); Offices of Provost, VPRG and Dean of Science, HKUST (VPRGO12SC02 to K.H.); Chinese University of Hong Kong (CUHK) Improvement on Competitiveness in Hiring New Faculty Funding Scheme (Ref. 133), CUHK Faculty Startup Fund and Alzheimer’s Association Research Fellowship (AARF-17-531566) to H.-M, C.
该研究受到了国家自然科学基金、厦门大学校长基金、福建省卫生教育联合攻关基金等的资助
Traffic channelization method in t-intersections with multiple traffic modes in Beijing
This paper focuses on city road crosses between main road and branch road at no signal control T-intersection. Compared with traffic signal control T-intersection. no traffic signal control T-intersection has the characteristics of unclear road right, traffic disorder-the serious conflict among pedestrians and bicycles and motor vehicles, pedestrians and cyclists are less safe and comfortable
Thermodynamic analysis of a new ammonia-water power cycle
A new ammonia-water power cycle (AWPC) basing on Kalina cycle is presented in this paper, which supply an effective way for low-moderate temperature geothermal power in China. The thermodynamic models of AWPC are established considering of the ratio of power generation as the optimization objective, and the binary cycle systems are analyzed. The theoretical results of AWPC show that there exists the optimum circulation ratio of 4, along with concentration difference of the ammonia-water solution of 12%-13%. And higher concentration of the ammonia-water solution will improve the performance of AWPC, while adding terminal temperature difference of the solution heat exchanger will improve the ratio of power generation
Numerical Analysis of Conjugated Heat and Mass Transfer of Helical Hollow Fiber Membrane Tube Bank for Seawater Distillation
A numerical study on the conjugated heat-mass transfer of helical hollow fiber membrane tube bank (HFMTB) for seawater desalination was carried out. Physical and mathematical models of fluid flow, temperature and humidity distribution were constructed to investigate the influences of flow type, Reynolds number, and temperature on the conjugated heat-mass transfer performance of hollow fibers in the distillation membrane module. The conjugated heat-mass transfer characteristics of HFMTB were discussed by utilizing the friction coefficient, Nusselt number (Nu), and Sherwood number (Sh). Results demonstrate that a distillation efficiency enhancement of 29% compared to the straight HFMTB has been detected for four-helical HFMTB configuration, though the friction coefficient of such a module is about 4 times of their straight counterparts. The values of average Nu and Sh numbers are increasing with tube number, which improves distillation efficiency. The effect of flow type has been studied by employing the upstream and downstream flows to the double-helical HFMTB, demonstrating upstream flow type is more conducive to the heat-mass transfer process. Both the outlet air humidity (omega) and distillation efficiency (eta) decrease with the air-side Reynolds number (Re-a) and inlet air temperature in the helical HFMTB while increasing with the solution-side Reynolds number (Re-s) and inlet solution temperature. Overall, the obtained results indicate that helical HFMTB applying upstream flow has great potential to achieve high-performance SGMD for seawater desalination. It is anticipated that the present work can assist in a better understanding of the membrane desalination process in HFMTB and thus provide theoretical suggestions for further optimization and development