Ruled surfaces generated by some special curves in Euclidean 3-Space

In this paper, a family of ruled surfaces generated by some special curves using a Frenet frame of that curves in Euclidean 3-space is investigated. Some important results are obtained in the case of general helices as well as slant helices. Moreover, as an application, circular general helices, spherical general helices, Salkowski curves and circular slant helices, which illustrate the results, are provided and graphed.     

Horizon problem remediation via deformed phase space

We investigate the effects of a special kind of dynamical deformation between the momenta of the scalar field of the Brans–Dicke theory and the scale factor of the FRW metric. This special choice of deformation includes linearly a deformation parameter. We trace the deformation footprints in the cosmological equations of motion when the BD coupling parameter goes to infinity. One class of the solutions gives a constant scale factor in the late time that confirms the previous result obtained via another approach in the literature. This effect can be interpreted as a quantum gravity footprint in the coarse grained explanation. The another class of the solutions removes the big bang singularity, and the accelerating expansion region has an infinite temporal range which overcomes the horizon problem. After this epoch, there is a graceful exiting by which the universe enters in the radiation dominated era.     

Acousto-spinodal decomposition of compressible polymer solutions: early stage analysis

The structure and dynamics of early stage kinetics of pressure-induced phase separation of compressible polymer solutions via spinodal decomposition is analyzed using a linear Euler-Cahn-Hilliard model and the modified Sanchez Lacombe equation of state. The integrated density wave and Cahn-Hilliard equations combine the kinetic and structural characteristics of spinodal decomposition with density waves arising from pressure-induced couplings. When mass transfer rate is slower that acoustic waves, concentration gradients generate density waves that cycle back into the spinodal decomposition dynamics, resulting in oscillatory demixing. The wave attenuation increases with increasing mass transfer rates eventually leading to nonoscillatory spinodal demixing. The novel aspects of acousto-spinodal decomposition arise from the coexistence of stable oscillatory density dynamics and the unstable monotonic concentration dynamics. Scaling laws for structure and dynamics indicate deviations from incompressible behavior, with a significant slowing down of demixing due to couplings with density waves. Partial structure factors for density and density-concentration reflect the oscillatory nature of acousto-spinodal modes at lower wave vectors, while the single maximum at a constant wave vector reflects the presence of a dominant mode in the linear regime. The computed total structure factor is in qualitative agreement with experimental data for a similar polymer solution.     

DABCO‐Catalyzed Efficient Synthesis of Naphthopyran Derivatives via One‐Pot Three‐Component Condensation Reaction at Room Temperature

Diazabicyclo[2.2.2]octane (DABCO) has been used as a mild and efficient catalyst for synthesis of 2‐amino‐3‐cyano naphthopyran derivatives via a one‐pot three‐component reaction of aromatic aldehydes, naphthols, and malononitrile at room temperature. The short reaction times, easy workup, good to excellent yields, and mild reaction conditions make this domino Knoevenagel–Michael reaction both practical and attractive.     

A Remark on the Linearized Stability of Positive Solutions for Systems Involving the p-Laplacian

The aim of this paper is to prove some stability result for nonlinear elliptic systems of the form where Δ_p denotes the p-Laplacian operator defined by Δ_pz = div(|∇ z|^p-2∇ z); p > 2, Ω is a bounded domain in R^N (N > 1) with smooth boundary where with h = 1 when α = 1, λ is a positive parameter and f,g are C² functin on [0,∞) × [0,∞). We prove stability and instability results of positive stationary solutions under various choices of f and g.     

Synthesis of Novel 2‐Oxoquinoline Derivatives via Ugi‐Four‐Component‐Heck Reaction

The present study provides an efficient strategy for the preparation of novel N‐substituted‐4‐methyl‐quinolin‐1(2H)‐one derivatives via two‐step Ugi/Heck reaction. The procedure is based on the Ugi coupling between 2‐bromoanilines, various aromatic aldehydes, vinylacetic acid, and isocyanides, and then intramolecular Heck reaction, which leads to the formation of the title compounds in good yields.     

Effects of Sucrose and Trehalose on Stability,Kinetic Properties,and Thermal Aggregation of Firefly Luciferase

In this study, we used sugars as stabilizing additives to improve the thermostability and to inhibit aggregation of firefly luciferase. The combination of sucrose and trehalose has a strong stabilizing effect on firefly luciferase activity and prevents its thermoinactivation. These additives can also increase optimum temperature. It has been shown that the presence of both sucrose and trehalose can inhibit thermal aggregation of firefly luciferase and decrease bioluminescence decay rate. In order to understand the molecular mechanism of thermostabilization, we investigated the effects of sucrose and trehalose combination on the secondary structure of luciferase by Fourier transform infrared spectroscopy. Minor changes in content of secondary structure of firefly luciferase are observed upon treatment with additives.     

Completion of S-posets

In this paper, analogously to the construction of completion of pomonoids, we construct a completion of S-posets for a pomonoid?S, which is compatible with joins (supremums).