364 research outputs found
Seven common errors in finding exact solutions of nonlinear differential equations
We analyze the common errors of the recent papers in which the solitary wave
solutions of nonlinear differential equations are presented. Seven common
errors are formulated and classified. These errors are illustrated by using
multiple examples of the common errors from the recent publications. We show
that many popular methods in finding of the exact solutions are equivalent each
other. We demonstrate that some authors look for the solitary wave solutions of
nonlinear ordinary differential equations and do not take into account the well
- known general solutions of these equations. We illustrate several cases when
authors present some functions for describing solutions but do not use
arbitrary constants. As this fact takes place the redundant solutions of
differential equations are found. A few examples of incorrect solutions by some
authors are presented. Several other errors in finding the exact solutions of
nonlinear differential equations are also discussed.Comment: 42 page
Methyl Farnesoate Plays a Dual Role in Regulating \u3cem\u3eDrosophila\u3c/em\u3e Metamorphosis
Corpus allatum (CA) ablation results in juvenile hormone (JH) deficiency and pupal lethality in Drosophila. The fly CA produces and releases three sesquiterpenoid hormones: JH III bisepoxide (JHB3), JH III, and methyl farnesoate (MF). In the whole body extracts, MF is the most abundant sesquiterpenoid, followed by JHB3 and JH III. Knockout of JH acid methyl transferase (jhamt) did not result in lethality; it decreased biosynthesis of JHB3, but MF biosynthesis was not affected. RNAi-mediated reduction of 3-hydroxy-3-methylglutaryl CoA reductase (hmgcr) expression in the CA decreased biosynthesis and titers of the three sesquiterpenoids, resulting in partial lethality. Reducing hmgcr expression in the CA of the jhamt mutant further decreased MF titer to a very low level, and caused complete lethality. JH III, JHB3, and MF function through Met and Gce, the two JH receptors, and induce expression of Kr-h1, a JH primary-response gene. As well, a portion of MF is converted to JHB3 in the hemolymph or peripheral tissues. Topical application of JHB3, JH III, or MF precluded lethality in JH-deficient animals, but not in the Met gce double mutant. Taken together, these experiments show that MF is produced by the larval CA and released into the hemolymph, from where it exerts its anti-metamorphic effects indirectly after conversion to JHB3, as well as acting as a hormone itself through the two JH receptors, Met and Gce
Methyl Farnesoate Plays a Dual Role in Regulating \u3cem\u3eDrosophila\u3c/em\u3e Metamorphosis
Corpus allatum (CA) ablation results in juvenile hormone (JH) deficiency and pupal lethality in Drosophila. The fly CA produces and releases three sesquiterpenoid hormones: JH III bisepoxide (JHB3), JH III, and methyl farnesoate (MF). In the whole body extracts, MF is the most abundant sesquiterpenoid, followed by JHB3 and JH III. Knockout of JH acid methyl transferase (jhamt) did not result in lethality; it decreased biosynthesis of JHB3, but MF biosynthesis was not affected. RNAi-mediated reduction of 3-hydroxy-3-methylglutaryl CoA reductase (hmgcr) expression in the CA decreased biosynthesis and titers of the three sesquiterpenoids, resulting in partial lethality. Reducing hmgcr expression in the CA of the jhamt mutant further decreased MF titer to a very low level, and caused complete lethality. JH III, JHB3, and MF function through Met and Gce, the two JH receptors, and induce expression of Kr-h1, a JH primary-response gene. As well, a portion of MF is converted to JHB3 in the hemolymph or peripheral tissues. Topical application of JHB3, JH III, or MF precluded lethality in JH-deficient animals, but not in the Met gce double mutant. Taken together, these experiments show that MF is produced by the larval CA and released into the hemolymph, from where it exerts its anti-metamorphic effects indirectly after conversion to JHB3, as well as acting as a hormone itself through the two JH receptors, Met and Gce
Broadband laser polarization control with aligned carbon nanotubes
We introduce a simple approach to fabricate aligned carbon nanotube (ACNT)
device for broadband polarization control in fiber laser systems. The ACNT
device was fabricated by pulling from as-fabricated vertically-aligned carbon
nanotube arrays. Their anisotropic property is confirmed with optical and
scanning electron microscopy, and with polarized Raman and absorption
spectroscopy. The device was then integrated into fiber laser systems (at two
technologically important wavelengths of 1 and 1.5 um) for polarization
control. We obtained a linearly-polarized light output with the maximum
extinction ratio of ~12 dB. The output polarization direction could be fully
controlled by the ACNT alignment direction in both lasers. To the best of our
knowledge, this is the first time that ACNT device is applied to polarization
control in laser systems. Our results exhibit that the ACNT device is a simple,
low-cost, and broadband polarizer to control laser polarization dynamics, for
various photonic applications (such as material processing, polarization
diversity detection in communications), where the linear polarization control
is necessary.Comment: 5 pages, 6 figure
A transformed rational function method and exact solutions to the 3+1 dimensional Jimbo-Miwa equation
A direct approach to exact solutions of nonlinear partial differential
equations is proposed, by using rational function transformations. The new
method provides a more systematical and convenient handling of the solution
process of nonlinear equations, unifying the tanh-function type methods, the
homogeneous balance method, the exp-function method, the mapping method, and
the F-expansion type methods. Its key point is to search for rational solutions
to variable-coefficient ordinary differential equations transformed from given
partial differential equations. As an application, the construction problem of
exact solutions to the 3+1 dimensional Jimbo-Miwa equation is treated, together
with a B\"acklund transformation.Comment: 13 page
A Mechanistic Approach to Understanding the Factors Affecting Drug Absorption: A Review of Fundamentals
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97203/1/00970002042006005.pd
The modified alternative (G’/G)-expansion method to nonlinear evolution equation: application to the (1+1)-dimensional Drinfel’d-Sokolov-Wilson equation
Sensing and Tactile Artificial Muscles from Reactive Materials
Films of conducting polymers can be oxidized and reduced in a reversible way. Any intermediate oxidation state determines an electrochemical equilibrium. Chemical or physical variables acting on the film may modify the equilibrium potential, so that the film acts as a sensor of the variable. The working potential of polypyrrole/DBSA (Dodecylbenzenesulfonic acid) films, oxidized or reduced under constant currents, changes as a function of the working conditions: electrolyte concentration, temperature or mechanical stress. During oxidation, the reactive material is a sensor of the ambient, the consumed electrical energy being the sensing magnitude. Devices based on any of the electrochemical properties of conducting polymers must act simultaneously as sensors of the working conditions. Artificial muscles, as electrochemical actuators constituted by reactive materials, respond to the ambient conditions during actuation. In this way, they can be used as actuators, sensing the surrounding conditions during actuation. Actuating and sensing signals are simultaneously included by the same two connecting wires
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