6-Chlorothieno[2,3-<Emphasis Type="Italic">e</Emphasis>]-1,4,2-dithiazine-3(2<Emphasis Type="Italic">H</Emphasis>)-thione-1,1-dioxide,Ammonium Salt Sesquihydrate: Synthesis,Crystal Structure and Density Functional Calculations

Abstract  

The title compound crystallizes in the monoclinic space group C2/c space group, with unit cell dimensions of a = 15.6684(3) ?, b = 7.3974(2) ?, c = 21.2669(5) ?; β = 106.7770(10)° (Z = 8). In the title compound, NH₄ ⁺·C₅HClNO₂S₄ ^–·1.5 H₂O, the 1,4,2-dithiazine ring adopts a distorted half-chair conformation. The structure displays several cooperative intermolecular N/O–H···N/O/S hydrogen-bonding interactions, giving rise to a two-dimensional layers packing motif. The layers are built up from seven component entities formed via extensive intermolecular N/O–H···N/O/S hydrogen bonds involving 6-chlorothieno[2,3-e]-1,4,2-dithiazine-3(2H)-thione-1,1-dioxide anions, ammonium cations and water molecules. The geometry of the title compound was fully optimized using a Density functional B3LYP/6-31G(d) and B3LYP/6-31+G(d) methods and the results were consistent with experimental values. The binding energy and associated basis set superposition as well as the thermodynamic quantities were calculated.     

Long-time Instability and Unbounded Sobolev Orbits for Some Periodic Nonlinear Schrödinger Equations

We study the energy cascade problematic for some nonlinear Schrödinger equations on ${\mathbb{T}^2}$ in terms of the growth of Sobolev norms. We define the notion of long-time strong instability and establish its connection to the existence of unbounded Sobolev orbits. This connection is then explored for a family of cubic Schrödinger nonlinearities that are equal or closely related to the standard polynomial one ${|u|^2u}$ . Most notably, we prove the existence of unbounded Sobolev orbits for a family of Hamiltonian cubic nonlinearities that includes the resonant cubic NLS equation (a.k.a. the first Birkhoff normal form).     

An improved chaos-based secure communication technique using a novel encryption function with an embedded cipher key

In this paper, a secure communication technique, using a chaotic system with a single adjustable parameter and a single observable time series, is proposed. The chosen chaotic system, which is a variant of the famous Rikitake model, has a special structure for which the adjustable parameter appears in the dynamic equation of the observable time series. This particular structure is used to build a synchronization-based state observer that is decoupled from the adaptive parameter identifier. A local Lyapunov function is used to design the parameter identifier, with an adjustable convergence rate that guarantees the stability of the overall system. A two-channel transmission method is used to exemplify the suggested technique where the secret message is encoded using a nonlinear function of both the chaotic states and the adjustable parameter of the chaotic system that acts as a secret key. Simulations show that, at the receiver, the signal can be efficiently retrieved only if the secret key is known, even when both the receiver and the transmitter are in perfect synchronization. The proposed technique is demonstrated to have improved security and privacy against intruders, when compared to other techniques reported in the literature, while being simple to implement using both analog and digital hardware. In addition, the chosen chaotic system is shown to be flexible in accommodating the transmission of signals with variable bandwidths, which promotes the superiority and versatility of the suggested secure communication technique.     

Peristaltic blood flow with gold nanoparticles as a third grade nanofluid in catheter: Application of cancer therapy

Cancer is dangerous and deadly to most of its patients. Recent studies have shown that gold nanoparticles can cure and overcome it, because these particles have a high atomic number which produce the heat and leads to treatment of malignancy tumors. A motivation of this article is to study the effect of heat transfer with the blood flow (non-Newtonian model) containing gold nanoparticles in a gap between two coaxial tubes, the outer tube has a sinusoidal wave traveling down its wall and the inner tube is rigid. The governing equations of third-grade fluid along with total mass, thermal energy and nanoparticles are simplified by using the assumption of long wavelength. Exact solutions have been evaluated for temperature distribution and nanoparticles concentration, while approximate analytical solutions are found for the velocity distribution using the regular perturbation method with a small third grade parameter. Influence of the physical parameters such as third grade parameter, Brownian motion parameter and thermophoresis parameter on the velocity profile, temperature distribution and nanoparticles concentration are considered. The results pointed to that the gold nanoparticles are effective for drug carrying and drug delivery systems because they control the velocity through the Brownian motion parameter $N_b$ and thermophoresis parameter $N_t$. Gold nanoparticles also increases the temperature distribution, making it able to destroy cancer cells.     

Pyrrolizine/Indolizine-NSAID Hybrids: Design,Synthesis, Biological Evaluation,and Molecular Docking Studies

In the current study, eight new hybrids of the NSAIDs, ibuprofen and ketoprofen with five pyrrolizine/indolizine derivatives were designed and synthesized. The chemical structures of these hybrids were confirmed by spectral and elemental analyses. The antiproliferative activities of these hybrids (5 μM) was investigated against MCF-7, A549, and HT-29 cancer cell lines using the cell viability assay, MTT assay. The results revealed 4–71% inhibition of the growth of the three cancer cell lines, where 8a,e,f were the most active. In addition, an investigation of the antiproliferative activity of 8a,e,f against MCF-7 cells revealed IC₅₀ values of 7.61, 1.07, and 3.16 μM, respectively. Cell cycle analysis of MCF-7 cells treated with the three hybrids at 5 μM revealed a pro-apoptotic increase in cells at preG1 and cell cycle arrest at the G1 and S phases. In addition, the three hybrids induced early apoptotic events in MCF-7 cells. The results of the molecular docking of the three hybrids into COX-1/2 revealed higher binding free energies than their parent compounds 5a,c and the co-crystallized ligands, ibuprofen and SC-558. The results also indicated higher binding free energies toward COX-2 over COX-1. Moreover, analysis of the binding modes of 8a,e,f into COX-2 revealed partial superposition with the co-crystallized ligand, SC-558 with the formation of essential hydrogen bonds, electrostatic, or hydrophobic interactions with the key amino acid His90 and Arg513. The new hybrids also showed drug-likeness scores in the range of 1.06–2.03 compared to ibuprofen (0.65) and ketoprofen (0.57). These results above indicated that compounds 8a,e,f deserve additional investigation as potential anticancer candidates.     

New N-acyl, N-alkyl, and N-bridged derivatives of rac-6,6′,7,7′-tetramethoxy-1,1′,2,2′,3,3′,4,4′-octahydro-1,1′-bisisoquinoline

The preparation of potential new ligand systems based on the rac-1,1′,2,2′,3,3′,4,4′-octahydro-6,6′,7,7′-tetramethoxy-1,1′-bisisoquinoline skeleton has been investigated. Syntheses of N-(2-bromobenzyl), N-(3-acetoxybenzyl), N-acetyl, N-chloroacetyl, N-chlorocarbonyl, N-ethoxycarbonyl and N-tert-butyloxycarbonyl derivatives and five macrocyclic, polyether containing derivatives are described.     

Copper(II) complexes of lipophilic aminoglycoside derivatives for the amino acid enantiomeric separation by ligand-exchange liquid chromatography

In this paper, a new class of ligand-exchange chiral stationary phase (LE-CSP) based on the copper complexes of lipophilic aminoglycoside derivatives was reported. Different stationary phases were developed by coating reversed-phase liquid chromatography supports with three neamine derivatives carrying a lipophilic octadecyl chain at the 4', 5 and 6 positions, respectively. The enantioselective ability of these LE neamine-based CSPs was evaluated and the 4'-derivative coated column was found to be the most interesting one for the amino acid resolution. The effects of the variation of several chromatographic parameters on the enantioseparation were evaluated in order to identify the analysis optimal conditions.     

Chiral ligand-exchange chromatography of amino acids using porous graphitic carbon coated with a dinaphthyl derivative of neamine

In this paper, we describe the preparation and the evaluation of a porous graphitic carbon (PGC) column coated with a new dinaphthyl derivative of neamine for chiral ligand-exchange (LE) chromatography. It was shown that the graphitic surface/dinaphthyl anchor system efficiently (1.15 μmol/m²) and stably (three months of intensive use) adsorbs the neamine template onto the chromatographic support. The resulting coated PGC stationary phase showed appreciable LE-based enantioselective properties towards several native amino acids. Chromatographic separation of methionine enantiomers using a dinaphtyl neamine-based ligand-exchange chiral stationary phase     

A simple elemental continuity based model application to study the anaerobic microbial activity for the treatment of dairy manure

A simple anaerobic digestion (AD) model was formulated with emphasis on understanding the microbial activity during AD. The model was formulated according to two main rules that regulate the microbial growth. The first rule was maintaining the elemental continuity of macronutrients C, H, N, O, P, and S. The second rule satisfied the thermodynamics of the main AD catabolic reactions: acidogenesis and both acetotrophic and hydrogenotrophic methanogenesis. Accordingly, the stoichiometric parameters were evaluated as functions of the bacterial yield. The model also considered the enzymatic hydrolysis of solid waste. For a known solid waste composition, experimental data was utilized to estimate microbial initial concentrations, yields and kinetics, i.e., to achieve better understanding of the main AD microbial activity. The model was applied to three sets of batch experiments focusing on anaerobic dairy manure degradation. The model predicted the degradation dynamics, estimated the bacterial concentration in different inoculums, and evaluated the effect of inoculum ratios in speeding up the degradation. Elemental continuity based formulation of the model evaluated additional components that are necessary for future studies of macronutrients recovery, limitation/toxic effects, and chemical equilibrium.