Nonlinear Dynamics of a PI Hydroturbine Governing System with Double Delays

A PI hydroturbine governing system with saturation and double delays is generated in small perturbation. The nonlinear dynamic behavior of the system is investigated. More precisely, at first, we analyze the stability and Hopf bifurcation of the PI hydroturbine governing system with double delays under the four different cases. Corresponding stability theorem and Hopf bifurcation theorem of the system are obtained at equilibrium points. And then the stability of periodic solution and the direction of the Hopf bifurcation are illustrated by using the normal form method and center manifold theorem. We find out that the stability and direction of the Hopf bifurcation are determined by three parameters. The results have great realistic significance to guarantee the power system frequency stability and improve the stability of the hydropower system. At last, some numerical examples are given to verify the correctness of the theoretical results

Phylogeny and Androecial Evolution in Schisandraceae, Inferred from Sequences of Nuclear Ribosomal DNA its and Chloroplast DNA \u3ci\u3etrn\u3c/i\u3eL-F Regions

Sequences of nuclear ribosomal DNA ITS and chloroplast trnL‐F regions were used to construct a phylogeny of Schisandraceae. The results show that there are two major clades in Schisandraceae. One is composed entirely of Schisandra species; the other contains a mixture of Schisandra and Kadsura species. Molecular data place Smith’s sect. Sphaerostema of Schisandra prominently within Kadsura, and thus neither Schisandra nor Kadsura is monophyletic, refuting the traditional division of the family into two genera based on morphological characters of mature fruits. The sister relationship between S. glabra (North America) and S. bicolor (China) and the monophyly of sect. Sphaerostema and sect. Kadsura are strongly supported. The trnL‐F and combined data sets yield phylogenetic trees that are well resolved and concordant with androecial types of staminate flowers; however, they do not support the evolutionary pathways for androecia constructed by previous authors for Kadsura and Schisandra. The new alignment of species in Schisandraceae indicates that morphological characters traditionally used to construct phylogenetic relationships and evolutionary pathways, e.g., habit (deciduous vs. evergreen or semievergreen), fruit type (bacceta vs. separated apocarps), arrangement of flowers (solitary vs. paired or in glomerules), and pollen (3‐colpate vs. 6‐colpate), evolved more than once in the family. Preliminary observations suggest that the pentagonal androecium and gynoecium of S. glabra are thermogenic and that heat may play a role in the reproductive biology of S. glabra to enhance floral odor or simulate the temperature of brood sites for many types of insects

Γ-CT Measurement and CFD Simulation of Cross Section Gas Holdup Distribution in a Gas-Liquid Stirred Standard Rushton Tank

Cross Section Gas Holdup Distributions at 3/4 Dimensionless Static Liquid Height in a Gas-Liquid Stirred Standard Rushton Tank Were Measured using 137Cs Γ-CT Scan Measuring Technology at Larger Gas Flow Rates and Higher Impeller Rotating Speeds. the Obtained CT Scan Images and Digital Distribution Curves of Gas Holdup with Dimensionless Radius based on the CT Images Could Explain the Fluctuation Changes of Gas Holdup Distribution. the Dense Area of Gas Holdup Distribution Appeared in the Upper Space of Impeller Blades. Gas Holdup Increased Both with Gas Flow Rate and Impeller Rotating Speed, But Gas Flow Rate Had More Influence on Gas Holdup Than Impeller Rotating Speed. the Eulerian-Eulerian Two-Fluid Model Coupling with the Bubbles\u27 Coalescence and Break-Up Models, and the Drag Coefficient Model Were Established to Make CFD Simulation of Gas Holdup Distributions for the Gas-Liquid Stirred Rushton Tank under Different Gas Flow Rates and Impeller Rotating Speeds. © 2011 Elsevier Ltd

On the Measurement of Gas Holdup Distribution Near the Region of Impeller in a Gas-Liquid Stirred Rushton Tank by Means of Γ-CT

Three Flow Patterns of Flooding, Loading and Complete Recirculation in a Gas-Liquid Stirred Rushton Tank Were Identified based on Experimental Observation. the Gas-Liquid System Was Composed of Air and Water. under Different Operating Conditions of Gas Flow Rate and Impeller Rotating Speed, the Distribution of Gas Holdup Near the Region of Impeller Was Measured using a Γ-CT Scan Method. Both Quantitative Digital Distribution Curves of Gas Holdup and their Qualitative Color CT Images Were Obtained. at the Region of Impeller, There Was a Convex Characteristic Peak of Gas Holdup Distribution Both in Radial and in Axial Directions, and with the Region Being Gradually Away from the Impeller, the Distribution of Gas Holdup Became Flatter. the Values of Gas Holdup in S33 Regime Were a Little Higher Than Those in L33 Regime. Higher Impeller Rotating Speed Had Some Effect on the Increasing of Gas Holdup at the Region of Higher Axial Height. the Experimental Measurement Results Were Basically Consistent with Those Previously Published by Bombač. the Hole Number and Diameter of Sparger Had Little Influence on the Distribution of Gas Holdup, While the Sparger\u27s Installed Height Had Significant Influence on Them. When the Sparger Was Installed Close to the Bottom of Rushton Tank, a Comparatively Smoother Distribution of Gas Holdup above the Space of Impeller Could Be Obtained. the Research Results in This Paper Were Useful for Better Understanding of Gas Holdup Distribution Near the Region of Impeller of Rushton Tank and Could Also Provide Experimental Data for CFD Simulation. © 2012 Elsevier B.V

Scientometric trends and knowledge maps of global health systems research

Background: In the last few decades, health systems research (HSR) has garnered much attention with a rapid increase in the related literature. This study aims to review and evaluate the global progress in HSR and assess the current quantitative trends. Methods: Based on data from the Web of Science database, scientometric methods and knowledge visualization techniques were applied to evaluate global scientific production and develop trends of HSR from 1900 to 2012. Results: HSR has increased rapidly over the past 20 years. Currently, there are 28,787 research articles published in 3,674 journals that are listed in 140 Web of Science subject categories. The research in this field has mainly focused on public, environmental and occupational health (6,178, 21.46%), health care sciences and services (5,840, 20.29%), and general and internal medicine (3,783, 13.14%). The top 10 journals had published 2,969 (10.31%) articles and received 5,229 local citations and 40,271 global citations. The top 20 authors together contributed 628 papers, which accounted for a 2.18% share in the cumulative worldwide publications. The most productive author was McKee, from the London School of Hygiene \& Tropical Medicine, with 48 articles. In addition, USA and American institutions ranked the first in health system research productivity, with high citation times, followed by the UK and Canada. Conclusions: HSR is an interdisciplinary area. Organization for Economic Co-operation and Development countries showed they are the leading nations in HSR. Meanwhile, American and Canadian institutions and the World Health Organization play a dominant role in the production, collaboration, and citation of high quality articles. Moreover, health policy and analysis research, health systems and sub-systems research, healthcare and services research, health, epidemiology and economics of communicable and non-communicable diseases, primary care research, health economics and health costs, and pharmacy of hospital have been identified as the mainstream topics in HSR fields. These findings will provide evidence of the current status and trends in HSR all over the world, as well as clues to the impact of this popular topic; thus, helping scientific researchers and policy makers understand the panorama of HSR and predict the dynamic directions of research

Stress-Induced Epinephrine Enhances Lactate Dehydrogenase A and Promotes Breast Cancer Stem-Like Cells

Chronic stress triggers activation of the sympathetic nervous system and drives malignancy. Using an immunodeficient murine system, we showed that chronic stress–induced epinephrine promoted breast cancer stem-like properties via lactate dehydrogenase A–dependent (LDHA-dependent) metabolic rewiring. Chronic stress–induced epinephrine activated LDHA to generate lactate, and the adjusted pH directed USP28-mediated deubiquitination and stabilization of MYC. The SLUG promoter was then activated by MYC, which promoted development of breast cancer stem-like traits. Using a drug screen that targeted LDHA, we found that a chronic stress–induced cancer stem-like phenotype could be reversed by vitamin C. These findings demonstrated the critical importance of psychological factors in promoting stem-like properties in breast cancer cells. Thus, the LDHA-lowering agent vitamin C can be a potential approach for combating stress-associated breast cancer

Transcription phase, protein characteristics of DEV UL45 and prokaryotic expression, antibody preparation of the UL45 des-transmembrane domain

<p>Abstract</p> <p>Background</p> <p>Some UL45 gene function of Herpesvirus was reported. While there was no any report of the duck enteritis virus (DEV) UL45 protein as yet.</p> <p>Results</p> <p>The UL45 gene and des-transmembrane domain of UL45 (named UL45Δ gene, 295-675bp of UL45) of DEV were amplified by PCR and subcloned into the prokaryotic expression vector pET-32a(+). The constructed recombinant plasmids were transformed into the host strain BL21(DE3) PLysS and induced by IPTG. SDS-PAGE analysis showed the UL45 gene couldn't express while UL45Δ gene was highly expressed. His Purify Kit or salting-out could purify the protein effectively. Using the purified protein to immunize New-Zealand rabbits and produce polyclonal antibody. The agar diffusion reaction showed the titer of antibody was 1:32. Western blot analysis indicated the purified rabbit anti-UL45Δ IgG had a high level of specificity and the UL45 gene was a part of DEV genome. The transcription phase study of UL45 gene showed that expression of UL45 mRNA was at a low level from 0 to 18 h post-infection (pi), then accumulated quickly at 24 h pi and peaked at 42 h pi. It can be detected till 72 h pi. Besides, western blot analysis of purified virion and different viral ingredients showed that the UL45 protein resided in the purified virion and the viral envelope.</p> <p>Conclusions</p> <p>The rabbit anti-UL45Δ IgG was produced successfully and it can serve as a good tool for penetrating studies of the function of DEV UL45 protein. The transcription phase and protein characteristics analysis indicated that DEV UL45 gene was a late gene and UL45 protein may be a viral envelope protein.</p

Ablation of EYS in zebrafish causes mislocalisation of outer segment proteins, F-actin disruption and cone-rod dystrophy

Mutations in EYS are associated with autosomal recessive retinitis pigmentosa (arRP) and autosomal recessive cone-rod dystrophy (arCRD) however, the function of EYS and the molecular mechanisms of how these mutations cause retinal degeneration are still unclear. Because EYS is absent in mouse and rat, and the structure of the retina differs substantially between humans and Drosophila, we utilised zebrafish as a model organism to study the function of EYS in the retina. We constructed an EYS-knockout zebrafish-line by TALEN technology which showed visual impairment at an early age, while the histological and immunofluorescence assays indicated the presence of progressive retinal degeneration with a cone predominately affected pattern. These phenotypes recapitulate the clinical manifestations of arCRD patients. Furthermore, the EYS(−/−) zebrafish also showed mislocalisation of certain outer segment proteins (rhodopsin, opn1lw, opn1sw1, GNB3 and PRPH2), and disruption of actin filaments in photoreceptors. Protein mislocalisation may, therefore, disrupt the function of cones and rods in these zebrafish and cause photoreceptor death. Collectively, these results point to a novel role for EYS in maintaining the morphological structure of F-actin and in protein transport, loss of this function might be the trigger for the resultant cellular events that ultimately lead to photoreceptor death