Evolutionary design of oscillatory genetic networks

The present study is devoted to the design and statistical investigations of dynamical gene expression networks. In our model problem, we aim to design genetic networks which would exhibit stable periodic oscillations with a prescribed temporal period. While no rational solution of this problem is available, we show that it can be effectively solved by running a computer evolution of the network models. In this process, structural rewiring mutations are applied to the networks with inhibitory interactions between genes and the evolving networks are selected depending on whether, after a mutation, they closer approach the targeted dynamics. We show that, by using this method, networks with required oscillation periods, varying by up to three orders of magnitude, can be constructed by changing the architecture of regulatory connections between the genes. Statistical properties of designed networks, including motif distributions and Laplacian spectra, are considered.     

Tunable chromatic dispersion and dispersion slope compensator using a planar lightwave circuit lattice-form filter

A tunable chromatic dispersion and dispersion slope compensator is proposed that has a single lattice-form filter configuration. Wavelength dependence is intentionally added to its tunable couplers, which produces dispersion slope compensation in addition to the dispersion compensation. Dispersion tunability of +/- 500 ps/nm and a slope of -4.9 ps/nm(2) over 40 GHz are successfully demonstrated, thus meeting the requirement for 40 Gbits/s differential quadrature phase shift keying transmission with an 80 km long nonzero dispersion-shifted fiber.     

Precise Asymptotics of Boundary Layers for Damped Simple Pendulum Equations

We consider the simple pendulum equation with friction: $${\begin{array}{ll}-u''(t) - \vert u'(t)\vert + g(u(t)) & = \lambda \sin u(t), \quad t \in I := (-T, T), \\ \quad \quad \quad \quad \quad \quad \quad \quad \quad u(t) & > 0, \quad t \in I, \quad u(\pm T) = 0,\end{array}}$$ where T > 0 is a constant and λ > 0 is a parameter. The case without friction is known as the simple pendulum equation with self interaction, and the asymptotic shape of the solution as λ → ∞ is well understood. In this paper, we establish the asymptotic formula for the boundary layers of the solution u _λ for the equation above, and show that its boundary slope is steeper than that of the solution without damping term | u′(t)|.     

The Fujita–Kato approach to the Navier–Stokes equations in the rotational framework

Consider the Navier-Stokes equations in the rotational framework. It is proved that these equations possess a unique global mild solution for arbitrary speed of rotation provided the initial data u ₀ is small enough in the H^\frac12_s(\mathbbR³){H^{\frac12}_{\sigma}(\mathbb{R}^3)} -norm.     

Strategic investment timing under asymmetric access charge regulation in telecommunications

In a liberalized telecommunications market, an incumbent has several advantages over any entrant. An asymmetric access charge regulation for two such asymmetric firms stimulates competitive investment. We show that an entrant with a cost disadvantage has an incentive to invest as a leader under an asymmetric access charge regulation. These results fit well with the findings of previous empirical work. Moreover, we also investigate the effects of an asymmetric access charge regulation on competitive investment strategies.     

Pressure broadening coefficients of induced by for Venus atmosphere

Carbon dioxide (CO₂) induced pressure broadening coefficients of water vapor (H₂O) lines have been determined using a terahertz time-domain spectrometer (TDS). Thirty-two rotational transitions of H₂O were observed in the spectral range of 18– (550–3050 GHz) for the first time. Using TDS allows one to measure absorption spectra with one order of magnitude better precision than Fourier transform spectrometer in this frequency region. The precision of our broadening coefficient measurements was 2.4% in average. The measured CO₂ induced pressure broadening coefficients are compared to those calculated by the complex Robert–Bonamy formalism. The difference between the measurement and the theoretical estimation was in the range of -10.7% to +19.0% confirming the credibility of the theoretical approach. The impact on retrieval of water vapor abundance was examined by performing inversion analysis on H₂O spectra of Venus atmosphere obtained with the Submillimeter Wave Astronomy Satellite. In this example case, the retrieved water vapor mixing ratio reduces by half at the altitude region of 70–85 km when applying the newly measured broadening coefficient compared to the air-broadening coefficient, and changes by 5% compared to that estimated by the complex Robert–Bonamy formalism.     

Facile Synthesis of Dibenzotetracenedione Derivatives by Rhodium‐Catalyzed [2+2+2] Cycloaddition/Spontaneous Aromatization

It has been established that a cationic rhodium(I)/SEGPHOS complex catalyzes the [2+2+2] cycloaddition of biphenyl‐linked 1,7‐diynes with 1,4‐naphthoquinone and anthracene‐1,4‐dione. Conveniently, spontaneous aromatization proceeded upon removal of the rhodium complex by passing the reaction mixture through an alumina column, to give the corresponding dibenzotetracenediones and dibenzopentacenediones, respectively, in good yields. The obtained dibenzotetracenedione could be readily transformed into the corresponding dibenzotetracene in good yield. This dibenzotetracene showed blue fluorescence with a good quantum yield, which was significantly higher than those of tetracene, tetrabenzotetracene, and hexabenzotetracene.     

Enantioselective fluorination mediated by cinchona alkaloid derivatives/Selectfluor combinations: reaction scope and structural information for N-fluorocinchona alkaloids.

Cinchona-alkaloid/Selectfluor combinations efficiently fluorinate a variety of carbonyl compounds in a highly enantioselective manner to furnish chiral alpha-fluorocarbonyl compounds. The DHQB/Selectfluor combination is effective for the enantioselective fluorination of indanones and tetralones 1 in up to 91% ee. The first enantioselective syntheses of chiral derivatizing reagents 3 was accomplished with high ee and in high chemical yields by the DHQDA/Selectfluor combination. 3-Fluorooxindoles 7 were prepared with ee up to 83% using the (DHQ)2AQN/Selectfluor or the (DHQD)2PYR/Selectfluor combination. Since the combinations are conveniently prepared in situ from readily available reagents, the present system represents a practical method for enantioselective fluorination. X-ray crystallography and 1H NMR analyses of the cinchona alkaloids/Selectfluor combination have established that the species that mediate this novel reaction are N-fluoroammonium cinchona alkaloid tetrafluoroborates, which adopt open conformations.     

Furopyridines. VIII. Molecular structure and two-dimensional NMR spectral assignment of 2,14-dimethyl-8aβ-hydroxy-7,10-dioxo-5β,6β-(propano)-6α,8α-(ethanoimino)-trans-perhydroisoquinoline

This paper reports the two-dimensional nmr spectral assignment and the X-ray structural determination of 2,14-dimethyl-8β-hydroxy-7,10-dioxo-5β,6β-(propano)-6α,8α-(ethanoimino)-trans-perhydroisoquinoline V which was obtained from 7,10-dimethyl-2β-hydroxy-14-oxo-2,3-(methanoiminoethano)-3β,4β-(propano)-3,4,5,6,7,8-hexahydro-2H-pyrano[2,3-c]pyridine IV by isomerization with hydrochloric acid. Both the compounds IV and V afforded the same dimethiodide IV -2MeI, while the configurational isomer 2,14-dimethyl-8aβ-hydroxy-7,10-dioxo-5α,6β-(propano)-6α,8α-(ethanoimino)-trans-perhydroisoquinoline III gave monomethiodide III -Mel. The structures of these methiodides were also confirmed by X-ray analysis.