Youbo Liu

Bio: Youbo Liu is an academic researcher from Sichuan University. The author has contributed to research in topics: Electric power system & Computer science. The author has an hindex of 15, co-authored 136 publications receiving 951 citations. Previous affiliations of Youbo Liu include Southern University of Science and Technology.

MEK/ERK and p38 MAPK regulate chondrogenesis of rat bone marrow mesenchymal stem cells through delicate interaction with TGF-beta1/Smads pathway.

Abstract: Objectives This study was carried out to reveal functions and mechanisms of MEK/ERK and p38 pathways in chondrogenesis of rat bone marrow mesenchymal stem cells (BMSCs), and to investigate further any interactions between the mitogen-activated protein kinase (MAPK) and transforming growth factor-beta1 (TGF-beta1)/Smads pathway in the process. Materials and methods Chondrogenic differentiation of rat BMSCs was initiated in micromass culture, in the presence of TGF-beta1, for 2 weeks. ERK1/2 and p38 kinase activities were investigated by Western Blot analysis. Specific MAPK inhibitors PD98059 and SB20350 were employed to investigate regulatory effects of MEK/ERK and p38 signals on gene expression of chondrocyte-specific markers, and TGF-beta1 downstream pathways of Smad2/3. Results ERK1/2 was phosphorylated in a rapid but transient manner, whereas p38 was activated in a slow and sustained way. The two MAPK subtypes played opposing roles in mediating transcription of cartilage-specific genes for Col2alpha and aggrecan. TGF-beta1-stimulated gene expression of chondrogenic regulators, Sox9, Runx2 and Ihh, was also affected by activity of PD98059 and SB203580, to different degrees. However, influences of MAPK inhibitors on gene expression were relatively minor when not treated with TGF-beta1. In addition, gene transcription of Smad2/3 was significantly upregulated by TGF-beta1, but was regulated more subtly by treatment with MAPK inhibitors. Conclusions MAPK subtypes seemed to regulate chondrogenesis with a delicate balance, interacting with the TGF-beta1/Smads signalling pathway.

A MapReduce Based High Performance Neural Network in Enabling Fast Stability Assessment of Power Systems

Abstract: Transient stability assessment is playing a vital role in modern power systems. For this purpose, machine learning techniques have been widely employed to find critical conditions and recognize transient behaviors based on massive data analysis. However, an ever increasing volume of data generated from power systems poses a number of challenges to traditional machine learning techniques, which are computationally intensive running on standalone computers. This paper presents a MapReduce based high performance neural network to enable fast stability assessment of power systems. Hadoop, which is an open-source implementation of the MapReduce model, is first employed to parallelize the neural network. The parallel neural network is further enhanced with HaLoop to reduce the computation overhead incurred in the iteration process of the neural network. In addition, ensemble techniques are employed to accommodate the accuracy loss of the parallelized neural network in classification. The parallelized neural network is evaluated with both the IEEE 68-node system and a real power system from the aspects of computation speedup and stability assessment.

Down-regulated long non-coding RNA H19 inhibits carcinogenesis of renal cell carcinoma.

Abstract: Long non-coding RNAs (lncRNAs) have been shown to have important regulatory roles in cancer biology. LncRNA H19 has been recently shown to be upregulated and play important roles in several cancers such as breast cancer, bladder cancer, and gastric cancer. However, the role of H19 in clear cell renal carcinoma (ccRCC) remains largely unknown.The expression levels of lncRNA H19 in ccRCC tissues and renal cancer cell lines were evaluated by quantitative Real-time PCR (qRT-PCR). And its association with overall survival of patients was analyzed by statistical analysis. Small interfering RNA (siRNA) was used to suppress H19 expression in renal cancer cell lines. In vitro assays were performed to further explore its role in tumor progression.The relative level of H19 was significantly higher in ccRCC compared to the adjacent normal renal tissues. And higher expression of H19 was found in renal cancer cells compared to the nonmalignant renal cells HK-2. Furthermore, The ccRCC patients with higher H19 expression had more advanced clinical stage and poorer prognosis than those with lower expression, Kaplan-Meier analysis revealed that patients with higher H19 expression had a poorer overall survival and H19 expression could be an independent prognostic marker for ccRCC patient. The results of in vitro assays indicated that knockdown of H19 reduced cell proliferation, invasion, and migration. Our data suggested that lncRNA H19 might be considered as a potential prognostic indicator and a target for gene therapy of ccRCC.

Optimal planning of AC-DC hybrid transmission and distributed energy resource system: Review and prospects

Abstract: With the highly-extensive integration of distributed renewable energy resources (DER) into the grid, the power distribution system has changed greatly in the structure, function and operating characteristics. On this ground, An AC-DC hybrid DER system becomes necessary for effective management and control over DER. This paper first summarizes the physical characteristics and morphological evolution of AC-DC hybrid DER system. The impact of these new features on system configuration planning is analyzed with respect to its flexible networking, rich operation control modes, and tight source-network-load-storage coupling. Then, based on a review of the existing research, problems and technical difficulties are figured out in terms of converter modeling, steady-state analysis, power flow calculation, operating scenarios management, and optimization model solution. In light of the problems and difficulties, a framework for the configuration optimization of AC-DC hybrid DER systems is proposed. At last, the paper provides a prospect of key technologies from six aspects including morphology forecasting, coupling interaction analysis, uncertainty modeling, operation simulation, optimization model solving algorithm and comprehensive scheme evaluation.

Energy function analysis for power system stability

Abstract: (1990). ENERGY FUNCTION ANALYSIS FOR POWER SYSTEM STABILITY. Electric Machines & Power Systems: Vol. 18, No. 2, pp. 209-210.

Vimentin and epithelial-mesenchymal transition in human breast cancer : observations in vitro and in vivo

Abstract: Breast cancer is a highly prevalent disease among women worldwide. While the expression of certain proteins within these tumours is used for prognosis and selection of therapies, there is a continuing need for additional markers to be identified. A considerable amount of current literature, based predominantly on cell culture systems, suggests that a major mechanism responsible for the progression of breast cancer is due to tumour cells losing their epithelial features and gaining mesenchymal properties. These events are proposed to be very similar to the epithelial-mesenchymal transition (EMT) process that has been well characterised in embryonic development. For the developmental and putative cancer EMT, the cell intermediate filament status changes from a keratin-rich network which connects to adherens junctions and hemidesmosomes, to a vimentin-rich network connecting to focal adhesions. This review summarises observations of vimentin expression in breast cancer model systems, and discusses the potential role of EMT in human breast cancer progression, and the prognostic usefulness of vimentin expression.

A Survey of Relaxations and Approximations of the Power Flow Equations

Abstract: The power flow equations model the relationship between voltage phasors and power injections at nodes (buses) in an electric power system and are fundamental in their analysis and operation. A wealth of literature exists on these equations, many providing different representations of them. This monograph provides the first comprehensive survey of representations in the context of optimization. To achieve this the power flow representations surveyed are categorized as either relaxations or approximations. The techniques described in here form the basis of running an optimally efficient modern day power system. A Survey of Relaxations and Approximations of the Power Flow Equations is a must-read for all students and researchers working on the cutting edge of electric power systems.

Pythagorean fuzzy set: state of the art and future directions

Abstract: Pythagorean fuzzy set, generalized by Yager, is a new tool to deal with vagueness considering the membership grade $$\mu $$ and non-membership $$ u $$ satisfying the condition $$\mu ^2+ u ^2\le 1$$ . It can be used to characterize the uncertain information more sufficiently and accurately than intuitionistic fuzzy set. Pythagorean fuzzy set has attracted great attention of many scholars that have been extended to new types and these extensions have been used in many areas such as decision making, aggregation operators, and information measures. Because of such a growth, we present an overview on Pythagorean fuzzy set with aim of offering a clear perspective on the different concepts, tools and trends related to their extension. In particular, we provide two novel algorithms in decision making problems under Pythagorean fuzzy environment. It may be served as a foundation for developing more algorithms in decision making.

Fueling the fire: emerging role of the hexosamine biosynthetic pathway in cancer

Abstract: Altered metabolism and deregulated cellular energetics are now considered a hallmark of all cancers. Glucose, glutamine, fatty acids, and amino acids are the primary drivers of tumor growth and act as substrates for the hexosamine biosynthetic pathway (HBP). The HBP culminates in the production of an amino sugar uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that, along with other charged nucleotide sugars, serves as the basis for biosynthesis of glycoproteins and other glycoconjugates. These nutrient-driven post-translational modifications are highly altered in cancer and regulate protein functions in various cancer-associated processes. In this review, we discuss recent progress in understanding the mechanistic relationship between the HBP and cancer.