Synthesis and fungicidal activity of novel 2,3-disubstituted-1,3-benzoxazines

A series of new 2,3-disubstituted-3,4-dihydro-2H-1,3-benzoxazines were prepared in moderate to excellent yields by aza-acetalizations of aromatic aldehydes with 2-(N-substituted aminomethyl)phenols in the presence of TMSCl. Their structures were confirmed by IR, 1H-NMR, 13C-NMR, MS and elemental analysis. The fungicidal activities of the target compounds were preliminarily evaluated, and some compounds exhibited good activity against Rhizoctonia solani.     

Defective histone H3K27 trimethylation modification in embryos derived from heated mouse sperm

The mouse sperm genome is resistant to in vitro heat treatment, and embryos derived from heated sperm can support full-term embryonic development, but the blastocyst rate and implantation rate are lower compared to embryos derived from fresh sperm. In the present study, the patterns of DNA methylation, histone H4K12 (ACH4K12) acetylation, H3K9 trimethylation (H3K9-TriM), and H3K27 trimethylation (H3K27-TriM) in preimplantation embryos derived from 65 °C-heated sperm were investigated. Although no evident changes in global DNA methylation, histone H4K12 (ACH4K12) acetylation, and H3K9 trimethylation (H3K9-TriM) were found, significantly lower levels of H3K27-TriM, which was thought to be one of the reasons for low efficiency of mouse cloning, were found in the inner cell mass of heated-sperm derived blastocysts. Thus, defective modification of H3K27-TriM might contribute to compromised development of embryos derived from heated sperm.     

A REDUCED FE FORMULATION BASED ON POD METHOD FOR HYPERBOLIC EQUATIONS

A proper orthogonal decomposition(POD) method was successfully used in the reduced-order modeling of complex systems.In this paper,we extend the applications of POD method,namely,apply POD method to a classical finite element(FE) formulation for second-order hyperbolic equations with real practical applied background,establish a reduced FE formulation with lower dimensions and high enough accuracy,and provide the error estimates between the reduced FE solutions and the classical FE solutions and the implementation of algorithm for solving reduced FE formulation so as to provide scientific theoretic basis for service applications.Some numerical examples illustrate the fact that the results of numerical computation are consistent with theoretical conclusions.Moreover,it is shown that the reduced FE formulation based on POD method is feasible and efficient for solving FE formulation for second-order hyperbolic equations.     

Periodic and subharmonic solutions for a class of non-autonomous Hamiltonian systems

Some existence theorems are obtained for periodic and subharmonic solutions of a class of non-autonomous Hamiltonian systems. Our technical approach is based on a version of the Local Linking Theorem, and the Generalized Mountain Pass Theorem.     

1.55-μm coherent lidar based on SPA sinusoidal frequency demodulation techniques

A 1.55-μm all-solid frequency-modulated continuous-wave (FMCW) coherent lidar based on the sinusoidal frequency demodulation technique for range and velocity measurement is presented. Both the nonlinearity of linear modulation waveform and the difficulty in measuring the frequency of sinusoidal modulation sys- tem are circumvented by utilizing segmental-processing-average (SPA) techniques. The results demonstrate that the resolutions of range and velocity measurement are better than 2 mm and 0.1 mm/s, respectively. The system has numerous practical and potential applications in space missions.     

A note on lower bound of centered L2-discrepancy on combined designs

This note provides a theoretical justification of optimal foldover plans in terms of uniformity. A new lower bound of the centered L ₂-discrepancy values of combined designs is obtained, which can be used as a benchmark for searching optimal foldover plans. Our numerical results show that this lower bound is sharper than existing results when more factors reverse the signs in the initial design.     

Theoretical analysis of the heat dissipation mechanism in high power photonic crystal fiber lasers

Starting from the special structure of photonic crystal fiber (PCF), the heat dissipation model of a PCF laser is constructed. Based on the heat dissipation model, the temperature distributions along the radial and axial directions of the PCF (DC-Yb-17040) for forward pump of 200 W and two-end pump of 100 W each side are calculated numerically by using the finite element method (FEM). The results show that the temperature distribution for two-end pump mode is more even than that for forward pump mode and the maximum temperature in the fiber decreases by 178.16 °C. With the thermal power in fiber core being assumed to be fixed, the effects of the core radius, outer cladding radius, and air-clad width on the temperature distribution along the fiber are analyzed numerically. The results show that the changing of core radius only affects the temperature in core region slightly and the decreasing of air-clad width decreases the temperature in inner cladding and core regions effectively. Meanwhile, the temperature of the whole fiber can be decreased by increasing the cladding radius.     

Ionic liquids-doped organic-inorganic hybrid film for electrochemical immunoassay for hepatitis B surface antigen

A new mediator-free amperometric immunoassay for hepatitis B surface antigen (HBsAg) in human serum was designed by means of immobilizing horseradish peroxidase-hepatitis B surface antibodies conjugates (HRP-HBsAb) on ionic liquids-doped organic-inorganic hybrid film. The composite film including magnetic nanogold particles and nanoalumina particles provides a friendly microenvironment for the immobilization of biomolecules. The presence of ionic liquids enhances the electron communication between the immobilized biomolecules and the base electrode and improves the sensitivity of the electrochemical immunoassay. With a non-competitive immunoassay format, the formation of the immunocomplex between the immobilized HRP-HBsAb and HBsAg in sample solution exhibited a barrier of direct electrical communication between the immobilized HRP and the base electrode and changed the bioelectrocatalytic properties of the immobilized HRP towards H₂O₂ in the detection solution. Under optimal conditions, the developed immunosensors displayed a good current response in a dynamic range from 1.2 to 430 ng/mL with a limit of detection of 0.3 ng/mL HBsAg (at 3s). The proposed immunosensors have good precision, high sensitivity, acceptable stability, and reproducibility and could be used for the HBsAg detection in human serum with consistent results in comparison with those obtained by the enzyme-linked immunosorbent assay method.     

Aggregation of quaternary ammonium gemini surfactants C12-s-C12.2Br in n-heptane/n-hexanol solution: effect of the spacer chains on the critical reverse micelle concentrations

The critical reverse micelle concentrations of C(12)-s-C(12).2Br (s=2,3,4,5,6,8,12) in n-heptane/n-hexanol solutions, cmc(I)s, have been determined by absorption spectrum method using iodine as probe. The values of cmc(I)s are smaller than those of the critical micelle concentrations (cmc(aq)s) in aqueous solution and reach a maximum at s=4, which is similar to the variation of cmc(aq) with s. The variation of cmc(I) with s is attributed to the alteration in the spacer chain conformation, i.e. when the spacer is short enough, it may adopt stretch configuration and when the spacer is long, it tends to bend towards the continuous oil phase to achieve a more densely packing of the quaternary ammonium heads on the surface of the core.     

A blow-up criterion for compressible viscous heat-conductive flows

We study an initial boundary value problem for the three-dimensional Navier–Stokes equations of viscous heat-conductive fluids in a bounded smooth domain. We establish a blow-up criterion for the local strong solutions in terms of the temperature and the gradient of velocity only, similar to the Beale–Kato–Majda criterion for ideal incompressible flows.