3,693 research outputs found
Synthesis and Characterization of Nucleic Acid-functionalized Nanomaterials
Motor proteins such as kinesin move along microtubules in order to transport cellular cargos throughout the cell by obtaining energy from RNA hydrolysis which allows the cell to complete the tasks needed to stay alive. In this work, we developed synthetic molecular motors using DNA enzymes (DNAzyme) and fluorescent nanomaterials which mimic the functions and structures of motor proteins. A DNAzyme-capped CdS nanoparticle and a RNA-functionalized single-walled carbon nanotube (SWCNT) were used as a walker and a track in the motor platform, respectively. As a walking mechanism, the DNAzyme cleaved the RNA substrates in the presence of metal cations. The RNA molecules were functionalized with SWCNTs using pi-pi stacking. Due to their fluorescent properties under specific light excitations, they were visualized to track the position of our motor. In addition, we studied the kinetics of molecular motors in different environments. As a result, the fastest translocation velocity was found to be 1nm min-1 and the maximum displacement was 3µm. A turnover rate of 0.025s-1 was determined by making a kinetic model based on the density of the single motor reactions. We demonstrated that the cation concentration, type of metal cation, pH, and temperature all modify the kinetics of the molecular motor. In conclusion, we developed the bio-inspired synthetic motors using DNA nanotechnology and showed how to control their movements using design of structures and modification of chemical environments. In the future, we will develop the kinetic model to analyze their kinetics and design the optimized molecular motors on purpose
Erratum: Dirichlet Forms and Dirichlet Operators for Infinite Particle Systems: Essential Self-adjointness
We reprove the essential self-adjointness of the Dirichlet operators of
Dirchlet forms for infinite particle systems with superstable and
sub-exponentially decreasing interactions.Comment: This is an erratum to the work appeared in J. Math. Phys. 39(12),
6509-6536 (1998
Improvement of Fire Hydrant Design to Enhance Water Main Flushing
AbstractFlushing is a good practice to avoid problems related to sediment, bio-film growth, and corrosion. Artificial sediment was removed from fire hydrant with pilot scale water distribution main. The sediment removal in fire hydrant and main was carefully compared with different flow rate with velocity ranged from 0.3 to 3.0 m/s and the depth of fire hydrant from 0.5 m to 1.3m. The drain capability of fire hydrant decreased as the flow rate increased. Sediment with higher density was hard to remove from water main. The length effect of upward fire hydrant was relatively minor. Downward drain showed better efficiency for both sand and actual sediment
Environmental considerations of plastic behaviors for automobile applications
AbstractIt is well known fact that the thermo-mechanical behaviors of polymeric materials are strongly influenced by environmental factors, and, for automobiles, the mechanical properties of interior plastic structures are noticeably changed by being repeatedly exposed to environments such as sun light and rains. As the properties change, mechanical fits such as fasteners and clips in automobiles lose their tightness, creating unexpected noises. To consider Buzz, Squeak and Rattle (BSR) from initial stage of the interior design, it is very important to obtain, analyze and understand the structural behaviors of the materials under environmental changes as well as time. In this report, the mechanical property changes of the plastics for automobiles are measured to investigate the temperature and humidity effects. The samples are undergone different temperature and humidity conditions, and regularly taken out to measure the thermo-mechanical properties. The data are compared with the original samples, and analyzed for the properties change. Viscoelastic characteristics such as glass transition temperatures and storage/loss modulus were also investigate
More self-tuning solutions with
We find more self-tuning solutions by introducing a general form for
Lagrangian of a 3-index antisymmetric tensor field in the RS II
model. In particular, for the logarithmic Lagrangian, , we
obtained a closed form weak self-tuning solution.Comment: LaTeX file of 12 page
Combining first-principles modeling and symbolic regression for designing efficient single-atom catalysts in Oxygen Evolution Reaction on MoCO MXenes
In this study, we address the significant challenge of overcoming limitations
in catalytic efficiency for the oxygen evolution reaction (OER). The current
linear scaling relationships hinder the optimization of electrocatalytic
performance. To tackle this issue, we investigate the potential of designing
single-atom catalysts (SACs) on MoCO MXenes for electrochemical OER
using first-principles modeling simulations. By employing the Electrochemical
Step Symmetry Index (ESSI) method, we assess OER intermediates to fine-tune
activity and identify the optimal SAC for MoCO MXenes. Our findings
reveal that both Ag and Cu exhibit effectiveness as single atoms for enhancing
OER activity on MoCO MXenes. However, among the 21 chosen transition
metals (TMs) in this study, Cu stands out as the best catalyst for tweaking the
overpotential (). This is due to Cu's lowest overpotential compared
to other TMs, which makes it more favorable for OER performance. On the other
hand, Ag is closely aligned with ESSI=, making the tuning of its
overpotential more challenging. Furthermore, we employ symbolic regression
analysis to identify the significant factors that exhibit a correlation with
the OER overpotential. By utilizing this approach, we derive mathematical
formulas for the overpotential and identify key descriptors that affect
catalytic efficiency in electrochemical OER on MoCO MXenes. This
comprehensive investigation not only sheds light on the potential of MXenes in
advanced electrocatalytic processes but also highlights the prospect of
improved activity and selectivity in OER applications
The Influence of Quantum Critical Fluctuations of Circulating Current Order Parameters on the Normal State Properties of Cuprates
We study a model of the quantum critical point of cuprates associated with
the "circulating current" order parameter proposed by Varma. An effective
action of the order parameter in the quantum disordered phase is derived using
functional integral method, and the physical properties of the normal state are
studied based on the action. The results derived within the ladder
approximation indicate that the system is like Fermi liquid near the quantum
critical point and in disordered regime up to minor corrections. This implies
that the suggested marginal Fermi liquid behavior induced by the circulating
current fluctuations will come in from beyond the ladder diagrams.Comment: 7pages, 1 figure included in RevTex file. To appear in Phys. Rev.
Towards 5D Grand Unification without SUSY Flavor Problem
We consider the renormalization group approach to the SUSY flavor problem in
the supersymmetric SU(5) model with one extra dimension. In higher dimensional
SUSY gauge theories, it has been recently shown that power corrections due to
the Kaluza-Klein states of gauge fields run the soft masses generated at the
orbifold fixed point to flavor conserving values in the infra-red limit. In
models with GUT breaking at the brane where the GUT scale can be larger than
the compactification scale, we show that the addition of a bulk Higgs
multiplet, which is necessary for the successful unification, is compatible
with the flavor universality achieved at the compactification scale.Comment: JHEP style file of 35 pages with 3 figures, Version to appear in JHE
Folding potential with modern nuclear density functionals and application to 16O+208Pb reaction
Double folding potential is constructed using the M3Y interaction and the
matter densities of the projectile and target nuclei obtained from four
microscopic energy density functional (EDF) models. The elastic scattering
cross sections for the 16O+208Pb system are calculated using the optical model
with the double folding potentials of the four EDF models. We focus on the
correlation between the matter densities and the behavior the double folding
potential and the elastic scattering cross sections. First, the matter and
charge densities are examined by comparing the results of the four EDF models.
There is a slight difference in the density in the internal region, but it is
negligible in the outer region. Next, we calculate the double folding potential
with the matter densities obtained from the four EDF models. Differences
between the models are negligible in the outer region, but the potential depth
in the internal region shows model dependence, which can be understood from the
behavior of matter densities in the internal region. Another point is that the
double folding potential is shown to be weakly dependent on the incident
energy. Finally, the elastic scattering cross sections have no significant
model dependence except for the slight difference in the backward angle.Comment: 17 pages, 13 figure
Electrochemical properties of composite cathodes using Sm doped layered perovskite for intermediate temperature-operating solid oxide fuel cell
The authors are grateful for the support of the Basic Science Research Program, part of the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT and Future Planning (No. 2014R1A1A1004163).SmBaCo2O5+d (SBCO) showed the lowest observed Area Specific Resistance (ASR) value in the LnBaCo2O5+d (Ln: Pr, Nd, Sm, and Gd) oxide system for the overall temperature ranges tested. The ASR of a composite cathode (mixture of SBCO and Ce0.9Gd0.1O2−d) on a Ce0.9Gd0.1O2−d (CGO91) electrolyte decreased with respect to the CGO91 content; the percolation limit was also achieved for a 50 wt% SBCO and 50 wt% CGO91 (SBCO50) composite cathode. The ASRs of SBCO50 on the dense CGO91 electrolyte in the overall temperature range of 500 to 750 °C were relatively lower than those of SBCO50 on the CGO91 coated dense 8 mol % yttria-stabilized zirconia (8YSZ) electrolyte for the same temperature range. From 750 °C and for all higher temperatures tested, however, the ASRs of SBCO50 on the CGO91 coated dense 8YSZ electrolyte were lower than those of the CGO91 electrolyte. The maximum power densities of SBCO50 on the Ni-8YSZ/8YSZ/CGO91 buffer layer were 1.034 W cm−2 and 0.611 W cm−2 at 800 °C and 700 °C.PostprintPeer reviewe
- …