A new eudesmane type sesquiterpene from Inula viscosa

Investigation of Inula viscosa of Jordanian origin afforded the new sesquiterpene 1beta-hydroxyilicic acid in addition to the known 2beta-hydroxyilicic acid.     

Synthesis,Characterization, and Bioactivity of Novel Bicinnolines Having 1‐Piperazinyl Moieties

A number of novel bicinnolines containing piperazine moieties, 4a – o , were synthesized via polyphosphoric acid‐catalyzed intramolecular cyclization of the respective acyl amidrazone derivatives ( 3a – o ). On the other hand, the amidrazones ( 3a – o ) were prepared by reaction of N′,N″‐(biphenyl‐4,4′‐diyl)bis(2‐oxopropane hydrazonoyl chloride) ( 2 ) with the appropriate cyclic sec‐amines in the presence of trimethylamine in absolute ethanol. Structures of the newly synthesized compounds were confirmed by NMR and mass spectral data. The antitumor activity of compounds 4a – o was evaluated in vitro on human breast cancer MDA‐231 by a cell viability assay. Results revealed that compounds 4k , 4n , and 4o exhibit potential cytotoxic effects (>70%) on the cancer cells. Additionally, the antimicrobial activity of compounds 4a – o was evaluated against three clinical microbial strains: Escherichia coli (Gram‐negative bacteria), Staphylococcus aureus (Gram‐positive bacteria), and Candida albicans (fungi/yeast). Results revealed that compounds 4e and 4k exhibit good activity against all three strains included in the study and that compound 4d displays excellent activity against S. aureus strain with a minimum inhibitory concentration value of 0.187 mg/mL.     

Synthesis of 99mTc-cationic steroid antimicrobial-107 and in vitro evaluation

Ceragenins/cationic steroid antimicrobials (CSAs) are a group of cholic acid derivatives with many properties that make them favourable for application as anti-infective agents. CSA-107 is also a member of this group that was labelled with ^99mTc by using SnCl₂·2H₂O as reducing agent and Na–K tartrate as transchelating agent. Labelling efficiency was optimized by varying the amount of reducing agent, pH, and time of incubation. Labelling efficiency and the stability of ^99mTc-CSA-107 in human serum was determined by paper and thin layer chromatography, which were >95 and >90 % respectively. In vitro binding of ^99mTc-CSA-107 was >95 % determined by using Staphylococcus aureus bacteria.     

Novel results for global robust stability of delayed neural networks

This paper investigates the global robust convergence properties of continuous-time neural networks with discrete time delays. By employing suitable Lyapunov functionals, some sufficient conditions for the existence, uniqueness and global robust asymptotic stability of the equilibrium point are derived. The conditions can be easily verified as they can be expressed in terms of the network parameters only. Some numerical examples are also given to compare our results with previous robust stability results derived in the literature.     

Synthesis of 4,4′-biquinazoline alcohols as chiral catalysts in enantioselective alkynylation of aldehydes with phenyl acetylene

Optically active propargylic alcohols are important chiral-building blocks in asymmetric synthesis, while the asymmetric addition of a terminal alkyne to an aldehyde is one of the most important procedures to prepare these chiral-building blocks. In this work, a family of chiral 4,4′-biquinazoline alcohols has been conveniently prepared from the easily accessible (S)-2-acetoxycarboxylic acid chlorides by reaction sequences beginning with condensation and followed by key synthetic steps including chlorination, nickel(0)-mediated homocoupling, and deprotection in addition to being examined as potential ligands in the enantioselective addition of phenylacetylene to aldehydes. These chiral ligands can be combined with Ti(OiPr)₄ and then used to catalyze the asymmetric addition of zinc acetylide, produced in situ by the reaction of phenylacetylene with diethylzinc, to aldehydes. The best enantiomeric excess obtained in this study was 75%.     

Description of 160Dy nucleus by partial dynamical SU(3) symmetry

We considered the characteristic features of SU(3) partial dynamical symmetry in the interacting boson model framework to show the relevance of such intermediate symmetry structure in the nuclear spectroscopy of the ¹⁶⁰Dy nucleus. The predictions of SU(3)-PDS for the energy spectrum and the transition probabilities were compared with the most recent experimental data and an acceptable degree of agreement was achieved.     

Inhibition of Cu-amyloid-β by using bifunctional peptides with β-sheet breaker and chelator moieties

Breaking the mold: Inhibition of toxic amyloid-β (Aβ) aggregates and disruption of Cu-Aβ with subsequent redox-silencing of Cu have been considered promising strategies against Alzheimer's disease. The design and proof of concept of simple peptides containing a Cu-chelating/redox-silencing unit and an Aβ-aggregation inhibition unit (β-sheet breaker) is described (see scheme).     

Emission properties of Mn doped ZnO nanoparticles prepared by mechanochemical processing

Mechanochemical processing was reported to introduce lot of crystal defects which can significantly influence emission properties. Nevertheless, to the best of our knowledge, there are no reports on effect of mechanochemical processing on emission properties of transition metal ion doped ZnO. In this study, Zn_1?xMn_xO nanoparticles with different Mn content (x=0, 0.02, 0.04, 0.06, 0.08, and 0.1) were prepared by mechanochemical processing to study the effect of Mn doping and processing on emission properties. Confirmation of nanoparticles size and nanocrystalline nature of hexagonal wurtzite ZnO structure is carried out using transmission electron microscopy (TEM) and selected area electron diffraction (SAED), respectively. The samples were also characterized using Fluorescence Spectroscope before and after heat-treatment. The emission studies revealed that blue emission intensity is stronger compared to UV and green emission in contrast to the earlier reports, where other synthesis routes were employed for the ZnO nanoparticles' preparation. The blue emission originates from the zinc interstitial (Zn_i) and oxygen interstitial (O_i) defects, which indicate that the mechanochemical route resulted in more interstitial defects compared to oxygen substitution (O_Zn) and oxygen vacancy (V_o) defects which otherwise would give green emission. Mn doping resulted in shifting of near-band-edge (NBE) emission and the reduction in the intensities of NBE, blue and green emissions. The initial red shift at lower Mn content could be due to s–d and p–d exchange interactions as well as band tailing effect where as the blue shift at higher Mn content can be attributed to the Burstein-Moss shift. The reduction in emission intensity could be due to non-radiative recombination processes promoted by Mn ions with increasing Mn content.     

Dissipative spherical collapse of charged anisotropic fluid in $$f(R)$$ gravity

In this paper, we present the next-to-leading order QCD corrections for di-lepton, di-electroweak boson ( $ZZ$ , $W^+W^-$ ) production in both the SM and the ADD model, matched to the HERWIG parton shower using the aMC@NLO framework. A selection of results at the 8 TeV LHC, which exhibit deviations from the SM as a result of the large extra-dimension scenario, are presented.