1,577 research outputs found
Mitochondrial DNA mutations in disease and aging
The small mammalian mitochondrial DNA (mtDNA) is very gene dense and encodes factors critical for oxidative phosphorylation. Mutations of mtDNA cause a variety of human mitochondrial diseases and are also heavily implicated in age-associated disease and aging. There has been considerable progress in our understanding of the role for mtDNA mutations in human pathology during the last two decades, but important mechanisms in mitochondrial genetics remain to be explained at the molecular level. In addition, mounting evidence suggests that most mtDNA mutations may be generated by replication errors and not by accumulated damage
Electromagnetic field in a cavity induced by gravitational waves
The detection method of gravitational waves (GW) using electromagnetic (EM)
cavities has garnered significant attention in recent years. This paper
thoroughly examines the analysis for the perturbation of the EM field and
raises some issues in the existing literature. Our work demonstrates that the
rigid condition imposed on the material, as provided in the literature, is
inappropriate due to its reliance on a gauge-dependent quantity that cannot be
controlled experimentally. Instead, we incorporate elasticity into the material
and revise the governing equations for the electric field induced by GWs,
expressing them solely in terms of gauge-invariant quantities. Applying these
equations to a cylindrical cavity with the TM010 mode, we present the GW
antenna pattern for the detector
Measurement-based Close-in Path Loss Modeling with Diffraction for Rural Long-distance Communications
In this letter, we investigate rural large-scale path loss models based on
the measurements in a central area of South Korea (rural area) in spring. In
particular, we develop new close-in (CI) path loss models incorporating a
diffraction component. The transmitter used in the measurement system is
located on a hill and utilizes omnidirectional antennas operating at 1400 and
2250 MHz frequencies. The receiver is also equipped with omnidirectional
antennas and measures at positions totaling 3,858 (1,262 positions for LOS and
2,596 positions for NLOS) and 4,957 (1,427 positions for LOS and 3,530
positions for NLOS) for 1400 and 2250 MHz, respectively. This research
demonstrates that the newly developed CI path loss models incorporating a
diffraction component significantly reduce standard deviations (STD) and are
independent of frequency, especially for LOS beyond the first meter of
propagation, making them suitable for use with frequencies up to a
millimeter-wave.Comment: 5 pages, 5 figure
Unleashing the full potential of Hsp90 inhibitors as cancer therapeutics through simultaneous inactivation of Hsp90, Grp94, and TRAP1
Cancer therapeutics: Extending a drug's reach A new drug that blocks heat shock proteins (HSPs), helper proteins that are co-opted by cancer cells to promote tumor growth, shows promise for cancer treatment. Several drugs have targeted HSPs, since cancer cells are known to hijack these helper proteins to shield themselves from destruction by the body. However, the drugs have had limited success. Hye-Kyung Park and Byoung Heon Kang at Ulsan National Institutes of Science and Technology in South Korea and coworkers noticed that the drugs were not absorbed into mitochondria, a key cellular compartment, and HSPs in this compartment were therefore not being blocked. They identified a new HSP inhibitor that can reach every cellular compartment and inhibit all HSPs. Testing in mice showed that this inhibitor effectively triggered death of tumor cells, and therefore shows promise for anti-cancer therapy. The Hsp90 family proteins Hsp90, Grp94, and TRAP1 are present in the cell cytoplasm, endoplasmic reticulum, and mitochondria, respectively; all play important roles in tumorigenesis by regulating protein homeostasis in response to stress. Thus, simultaneous inhibition of all Hsp90 paralogs is a reasonable strategy for cancer therapy. However, since the existing pan-Hsp90 inhibitor does not accumulate in mitochondria, the potential anticancer activity of pan-Hsp90 inhibition has not yet been fully examined in vivo. Analysis of The Cancer Genome Atlas database revealed that all Hsp90 paralogs were upregulated in prostate cancer. Inactivation of all Hsp90 paralogs induced mitochondrial dysfunction, increased cytosolic calcium, and activated calcineurin. Active calcineurin blocked prosurvival heat shock responses upon Hsp90 inhibition by preventing nuclear translocation of HSF1. The purine scaffold derivative DN401 inhibited all Hsp90 paralogs simultaneously and showed stronger anticancer activity than other Hsp90 inhibitors. Pan-Hsp90 inhibition increased cytotoxicity and suppressed mechanisms that protect cancer cells, suggesting that it is a feasible strategy for the development of potent anticancer drugs. The mitochondria-permeable drug DN401 is a newly identified in vivo pan-Hsp90 inhibitor with potent anticancer activity
Performance Analysis of the Linear Induction Motor for the Deep-Underground High-Speed GTX
Abstract -In order to develop a deep-underground great train express (GTX) in South Korea, the specifications decision and development of a traction control system (including an inverter and a traction motor), which considers a variety of route conditions, must be advanced. In this study, we examined the running resistance properties of a high-speed traction system based on a variety of tunnel types and vehicle organization methods. Then, we studied the power requirements necessary for the traction motor to maintain balanced speed in the high-speed traction system. From this, we determined the design criteria for the development of a high-speed traction system for use in the deep-underground GTX. Finally, we designed a linear induction motor (LIM) for a propulsion system, and we used the finite element method (FEM) to analyze its performance as it travelled through deep-underground tunnels
Convergence ― Divergence in Capitalism Revisited
Recently, there has been a surge of interest in analyzing the market as a social structure. One of the major issues is whether the industrialization paths in various countries have become divergent or convergent. In this paper, we attempt to compare South Korea and the United States. Research questions raised are: first, what are the main characteristics of the structural change in the market; and second, whether the evolving Korean industrial structure is converging toward the structure exhibited by advanced economies such as the United States? Because of active interventions of the Korean government in industrial development, we originally expected that the Korean Industrial Input/Output structures would differ from those of the United States. However, we found that Korean I/O structures are moving towards the U.S. structure as the Korean economy develops. We interpreted that the convergent path may have resulted from technological imperatives of inter-industry relations. During the market's evolutionary process, however, we found that the government participated in the evolution of such a market structure by selectively supporting key industries with its policy loans
Muon anomalous magnetic moment and the stabilized Randall-Sundrum scenario
We study the effects of extra dimension on the muon anomalous magnetic moment
in the stabilized Randall-Sundrum scenario. The effects of the Kaluza-Klein
states heavier than the cut-off scale expected to be of order are
neglected. Contribution from the spin-2 Kaluza-Klein states dominates over that
from the spin-0 radion. The recent BNL E821 results impose a strict constraint
on the parameter space of the model: TeV with
. Small is preferred if
is TeV scale.Comment: 9 pages, ReVTeX, reference added, version to appear in PL
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