Biginelli-type reaction: Efficient synthesis of 5-unsubstituted 3,4-dihydropyrimidin-2-ones and thiones from gem-dibromomethylarenes

In the present study, we are reporting a simple and efficient method for the one-pot synthesis of the biologically important heterocyclic molecules 5-unsubstituted 3,4-dihydropyrimidin-2-ones and thiones using gem-dibromomethylarenes, oxalacetic acid, and urea or thiourea. Gem-dibromomethylarenes are used as aldehyde equivalent for the efficient synthesis of 3,4-dihydropyrimidin-2-ones/thiones. This reaction offers advantages for the synthesis of these compounds, including ready availability of the starting materials, experimental simplicity and in good yields. Besides, the synthesized molecules are interesting for their biological and pharmacological actions.     

Carboranylpyrroles: a synthetic investigation

The unusual reactivity of carborane mono- and dialdehydes with pyrroles in the presence of acid catalysts leads to the formation of a new class of carboranyl mono- and dipyrro derivatives.     

Anti-cancer activity of novel dibenzo[b,f]azepine tethered isoxazoline derivatives

Background  

Nef is an HIV-1 accessory protein essential for viral replication and AIDS progression. Nef interacts with a multitude of host cell signaling partners, including members of the Src kinase family. Nef preferentially activates Hck, a Src-family kinase (SFK) strongly expressed in macrophages and other HIV target cells, by binding to its regulatory SH3 domain. Recently, we identified a series of kinase inhibitors that preferentially inhibit Hck in the presence of Nef. These compounds also block Nef-dependent HIV replication, validating the Nef-SFK signaling pathway as an antiretroviral drug target. Our findings also suggested that by binding to the Hck SH3 domain, Nef indirectly affects the conformation of the kinase active site to favor inhibitor association.     

Coupled spatial-soliton pairs in saturable nonlinear media

We present a simple and straightforward approach to investigate coupled spatial-soliton pairs of two copropagating mutually incoherent (i.e., both beams are fully spatially and temporally coherent, but are incoherent with respect to one another) light beams in saturable nonlinear media. The approach provides a deeper understanding of coupled spatial-soliton pairs and reveals many interesting features, including the entire existence curve of such solitons.     

Area-Efficient Arithmetic Expression Evaluation Using Deeply Pipelined Floating-Point Cores

Recently, it has become possible to implement floating-point cores on field-programmable gate arrays (FPGAs) to provide acceleration for the myriad applications that require high-performance floating-point arithmetic. To achieve high clock rates, floating-point cores for FPGAs must be deeply pipelined. This deep pipelining makes it difficult to reuse the same floating-point core for a series of dependent computations. However, floating-point cores use a great deal of area, so it is important to use as few of them in an architecture as possible. In this paper, we describe area-efficient architectures and algorithms for arithmetic expression evaluation. Such expression evaluation is necessary in applications from a wide variety of fields, including scientific computing and cognition. The proposed designs effectively hide the pipeline latency of the floating-point cores and use at most two floating-point cores for each type of operator in the expression. While best-suited for particular classes of expressions, the proposed designs can evaluate general expressions as well. Additionally, multiple expressions can be evaluated without reconfiguration. Experimental results show that the areas of our designs increase linearly with the number of types of operations in the expression and that our designs occupy less area and achieve higher throughput than designs generated by a commercial hardware compiler.     

Modification of Fluorescent Photoinduced Electron Transfer (PET) Sensors/Switches To Produce Molecular Photo‐Ionic Triode Action

The fluorophore‐spacer₁‐receptor₁‐spacer₂‐receptor₂ system (where receptor₂ alone is photoredox‐inactive) shows ionically tunable proton‐induced fluorescence off‐on switching, which is reminiscent of thermionic triode behavior. This also represents a new extension to modular switch systems based on photoinduced electron transfer (PET) towards the emulation of analogue electronic devices.     

Secure and reliable routing in cognitive radio networks

Due to the mobility of node and different spectrum availability pattern, CR networks are frequently divided into unpredictable partitions. Usually, these partitions are irregularly connected; hence, secure and reliable routing becomes major issue for these types of network. In order to overcome these issues, we propose a secure and reliable routing in CRN based on distributed Boltzmann–Gibbs learning algorithm. This algorithm is implemented for relay node selection phase. In addition, the authentication is done based on secure routing distributed Boltzmann–Gibbs learning algorithm. We consider the metrics such as trust value and total delay for the successful and reliable transmission of the packet. Also, in order to increase the reliability, we implement LDPC code at the time of relay node selection phase. The proposed code helps to cancel any kind of electronic interference and channel noise interference.     

Density of states of the binary alloy in the coherent potential approximation

The density of states of an electron in a binary alloy in the tight binding model is calculated in the single site coherent potential approximation (CPA) as a function of the concentration and the site energy difference. The fluctuations in the site energies due to the random environment is taken into account approximately by giving width to the site energy probability distribution function, which is normally a sum of two delta functions with proper weight factor.     

Charged particle motion in an electromagnetic field on Kerr background geometry

In this paper we study the trajectories of charged particles in an electromagnetic field superimposed on the Kerr background. The electromagnetic fields considered are of two types: (i) a dipole magnetic field with an associated quadrupole electric field, (ii) a uniform magnetic field. The contribution of the background geometry to the electromagnetic field is taken through the solutions of Petterson and Wald respectively. The effective potential is studied in detail for ther-motion of the particles in the equatorial plane and the orbits are obtained. The most interesting aspect of the study is the illustration of the effect of inertial frame dragging due to the rotation of the central star. This appears through the existence of nongyrating bound orbits at and inside the ergo surface. The presence of the magnetic field seems to increase the range of stable orbits, as was found in a previous study involving the Schwarzschild background.