13,966 research outputs found
A small segmented oscillating water column using a savonius rotor turbine
This paper outlines a project which addresses the use of a small segmented oscillating water column with three sections. The turbine utilises cascaded Savonius rotors (one for each section) and this system is developed and tested for validation of the performance algorithms. It is shown that the systems can be easily described and a system developed that can generate. It would be suitable for a shoreline location such as a harbour wall, where waves are random and not orthogonal to the column. Conversion rates in the region of 20 % are tabulated for the system with an output of 25 W peak. The paper will give a full algorithm for the system while the digest outlines some crucial points with regards to the sizing and operation of the column with respect to the wave frequency and wavelength. The turbine is fully characterized - the generator is a brushless permanent magnet machine connected to a diode bridge rectifier and variable load. © 2008 IEEE
Reconstructing the Star Formation History of the Galaxy
The evolution of the star formation rate in the Galaxy is one of the key
ingredients quantifying the formation and determining the chemical and
luminosity evolution of galaxies. Many complementary methods exist to infer the
star formation history of the components of the Galaxy, from indirect methods
for analysis of low-precision data, to new exact analytic methods for analysis
of sufficiently high quality data. We summarise available general constraints
on star formation histories, showing that derived star formation rates are in
general comparable to those seen today. We then show how colour-magnitude
diagrams of volume- and absolute magnitude-limited samples of the solar
neighbourhood observed by Hipparcos may be analysed, using variational calculus
techniques, to reconstruct the local star formation history. The remarkable
accuracy of the data coupled to our maximum-likelihood variational method
allows objective quantification of the local star formation history with a time
resolution of ~ 50 Myr. Over the past 3Gyr, the solar neighbourhood star
formation rate has varied by a factor of ~ 4, with characteristic timescale
about 0.5Gyr, possibly triggered by interactions with spiral arms.Comment: 12 pages, Proc. of the Sept. 20-24, 1999 Vulcano Workshop ``The
chemical evolution of the Milky Way: stars vs. clusters'', eds. F. Matteucci
& F. Giovanell
Cancer gene therapy targeting angiogenesis: An updated review
Since the relationship between angiogenesis and tumor growth was established by Folkman in 1971, scientists have made efforts exploring the possibilities in treating cancer by targeting angiogenesis. Inhibition of angiogenesis growth factors and administration of angiogenesis inhibitors are the basics of anti-angiogenesis therapy. Transfer of anti-angiogenesis genes has received attention recently not only because of the advancement of recombinant vectors, but also because of the localized and sustained expression of therapeutic gene product inside the tumor after gene transfer. This review provides the up-to-date information about the strategies and the vectors studied in the field of anti-angiogenesis cancer gene therapy. © 2006 The WJG Press. All rights reserved.published_or_final_versio
Comparison of hybrid-excitation fault-tolerant in-wheel motor drives for electric vehicles
Paper no. DS2-23Hybrid-excitation in-wheel motor drive receives the attractive merit for its fault-tolerant operation. This paper gives the performance comparison of three types of hybrid-excitation in-wheel motor drives in electric vehicles (EVs) for their fault-tolerant operations. By using finite-time element analysis, the torque output is utilized as the fault indicator to investigate the performances of each motor drive under normal, faulty, and remedial operations.published_or_final_versio
Situational-Context for Virtually Modeling the Elderly
The generalized aging of the population is incrementing the pressure over, frequently overextended, healthcare systems. This situations is even worse in underdeveloped, sparsely populated regions like Extremadura in Spain or Alentejo in Portugal. In this paper we propose an initial approach to use the Situational-Context, a technique to seamlessly adapt Internet of Things systems to the needs and preferences of their users, for virtually modeling the elderly. These models could be used to enhance the elderly experience when using those kind of systems without raising the need for technical skills. The proposed virtual models will also be the basis for further eldercare innovations in sparsely populated regions
Impact of soft handover and pilot pollution on video telephony in a commercial network
Soft handover (SHO) provides better support for user mobility. The quality of service (QoS) to the mobile wireless subscribers can also grant benefits from SHO. To analyze the impact of SHO on the circuit switched (CS) video telephony (VT); real-time measurements have been conducted on a commercial WCDMA mobile network in the CBD of Sydney, Australia. Live measurement provides a practical approach to evaluate performance of commercial network. The obtained SHO gain implies that better QoS can be achieved. Furthermore, the negative impact of pilot pollution on radio link quality has been demonstrated in this paper. ©2010 IEEE
Diagnostic Value of Methylated Human Telomerase Reverse Transcriptase in Human Cancers: A Meta-Analysis
published_or_final_versio
Regulation of TMPRSS6 by BMP6 and iron in human cells and mice.
Mutations in transmembrane protease, serine 6 (TMPRSS6), encoding matriptase-2, are responsible for the familial anemia disorder iron-refractory iron deficiency anemia (IRIDA). Patients with IRIDA have inappropriately elevated levels of the iron regulatory hormone hepcidin, suggesting that TMPRSS6 is involved in negatively regulating hepcidin expression. Hepcidin is positively regulated by iron via the bone morphogenetic protein (BMP)-SMAD signaling pathway. In this study, we investigated whether BMP6 and iron also regulate TMPRSS6 expression. Here we demonstrate that, in vitro, treatment with BMP6 stimulates TMPRSS6 expression at the mRNA and protein levels and leads to an increase in matriptase-2 activity. Moreover, we identify that inhibitor of DNA binding 1 is the key element of the BMP-SMAD pathway to regulate TMPRSS6 expression in response to BMP6 treatment. Finally, we show that, in mice, Tmprss6 mRNA expression is stimulated by chronic iron treatment or BMP6 injection and is blocked by injection of neutralizing antibody against BMP6. Our results indicate that BMP6 and iron not only induce hepcidin expression but also induce TMPRSS6, a negative regulator of hepcidin expression. Modulation of TMPRSS6 expression could serve as a negative feedback inhibitor to avoid excessive hepcidin increases by iron to help maintain tight homeostatic balance of systemic iron levels
Evaluation of Dynamic Cell Processes and Behavior Using Video Bioinformatics Tools
Just as body language can reveal a person’s state of well-being, dynamic changes in cell behavior and
morphology can be used to monitor processes in cultured cells. This chapter discusses how CL-Quant
software, a commercially available video bioinformatics tool, can be used to extract quantitative data on:
(1) growth/proliferation, (2) cell and colony migration, (3) reactive oxygen species (ROS) production, and
(4) neural differentiation. Protocols created using CL-Quant were used to analyze both single cells and
colonies. Time-lapse experiments in which different cell types were subjected to various chemical
exposures were done using Nikon BioStations. Proliferation rate was measured in human embryonic stem
cell colonies by quantifying colony area (pixels) and in single cells by measuring confluency (pixels).
Colony and single cell migration were studied by measuring total displacement (distance between the
starting and ending points) and total distance traveled by the colonies/cells. To quantify ROS production,
cells were pre-loaded with MitoSOX Red™, a mitochondrial ROS (superoxide) indicator, treated with
various chemicals, then total intensity of the red fluorescence was measured in each frame. Lastly, neural
stem cells were incubated in differentiation medium for 12 days, and time lapse images were collected
daily. Differentiation of neural stem cells was quantified using a protocol that detects young neurons. CLQuant
software can be used to evaluate biological processes in living cells, and the protocols developed in
this project can be applied to basic research and toxicological studies, or to monitor quality control in
culture facilities
Drawing Trees with Perfect Angular Resolution and Polynomial Area
We study methods for drawing trees with perfect angular resolution, i.e.,
with angles at each node v equal to 2{\pi}/d(v). We show:
1. Any unordered tree has a crossing-free straight-line drawing with perfect
angular resolution and polynomial area.
2. There are ordered trees that require exponential area for any
crossing-free straight-line drawing having perfect angular resolution.
3. Any ordered tree has a crossing-free Lombardi-style drawing (where each
edge is represented by a circular arc) with perfect angular resolution and
polynomial area. Thus, our results explore what is achievable with
straight-line drawings and what more is achievable with Lombardi-style
drawings, with respect to drawings of trees with perfect angular resolution.Comment: 30 pages, 17 figure
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