Spectroscopic,textural, electrical and magnetic properties of antimicrobial nano Fe(III) Schiff base complex

A novel Schiff base ligand (L) was prepared through condensation of 2,6‐diaminopyridine and dibenzoyl methane in a 1:1 ratio. This Schiff base ligand was used for complex formation reaction with Fe(III) chloride. The structures of the ligand and its complex were deduced from elemental analyses, mass spectroscopy, ¹H NMR, IR, UV‐Vis, electronic spectra, magnetic moment, molar conductivity measurements, thermogravimetric analyses and X‐ray diffraction. The molecular and electronic structures of both ligand and complex were optimized theoretically using density function theory (DFT) method. Moreover, the antimicrobial activities of the prepared compounds were studied and proven against some pathogenic bacteria. The Fe(III) complex had higher biological activity than that of the free ligand. Proceeding from the collected information, the properties of the complex were further investigated. The particle size was determined by dynamic light scattering technique to be 92.59 nm. Textural properties of the nano complex were studied by N₂ adsorption to estimate the specific surface area, pore volume and pore size distribution. The pores in the complex were found in the micropore–mesopore range. Differential scanning calorimetric measurements reveal the existence of four endothermic peaks at 243.8, 308, 339.8 and 380.5 K. Dielectric properties and conductivity were scanned at different frequencies and temperatures. The dielectric constant reaches a peak value of 600 at ~390 K, 30 Hz. A cross‐over from the universal dielectric response to the super linear power law of conductivity was reported for this complex at T ≤ 345 K. Finally, the AC‐magnetic susceptibility measurements were carried out in the low‐temperature region. The complex showed paramagnetic behavior with a slight change in the magnitude of its magnetic moment at T = 244 K.     

Synthesis,characterization and in vitro antimicrobial and anti‐breast cancer activity studies of metal complexes of novel pentadentate azo dye ligand

A new azo dye with N3O2 donor set of atoms has been synthesized via coupling reaction of 2,6‐diaminopyridine with p‐methoxybenzaldehyde. The molecular and electronic structure of the azo dye ligand (L) was optimized theoretically and the quantum chemical parameters were calculated. Molecular docking was used to predict the binding between L and the receptors of breast cancer mutant 3hb5‐oxidoreductase, crystal structure of Escherichia coli (3 T88) and crystal structure of Staphylococcus aureus (3q8u). The newly synthesized L was used for complex formation with Cr(III), Mn(II), Fe(III), Co.(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions. The nature of bonding and the stoichiometry of L and its mononuclear complexes were deduced from elemental analyses, spectroscopic, magnetic susceptibility, molar conductance, electron spin resonance and conductivity measurements, thermogravimetric analyses and powder X‐ray diffraction. Elemental analysis data show that the complexes have composition of ML type with an octahedral geometry for all the complexes. The activation thermodynamic parameters were calculated. The prepared azo dye and its metal complexes were tested against various Gram‐positive and Gram‐negative bacteria and a fungus. Most complexes exhibit antibacterial and antifungal activities against these organisms. Anticancer evaluation studies against standard breast cancer cell line were performed using various concentrations. The activity index was calculated. Copyright © 2016 John Wiley & Sons, Ltd.     

Poly(vinylalcohol)/poly(ethyleneglycol)/poly(ethyleneimine) blend membranes - structure and CO2 facilitated transport

Poly(vinylalcohol) (PVA)/poly(ethyleneimine) (PEI)/poly(ethyleneglycol) (PEG) blend membranes were prepared by solution casting followed by solvent evaporation. The effects of the blend polymer composition on the membrane structure and CO₂/N₂ permeation characteristics were investigated. IR spectroscopy evidenced strong hydrogen bonding interactions between amorphous PVA and PEI, and weaker interactions between PVA and PEG. DSC studies showed that PVA crystallization was partially inhibited by the interactions between amorphous PVA and PEI blend, in which PEG separated into nodules. The CO₂ permeability decreased with an increase in CO₂ partial pressure in feed gas, while the N₂ permeability remained constant. This result indicated that only CO₂ was transported by the facilitated transport mechanism. The CO₂ and N₂ permeabilities increased monotonically with the PEI content in the blend membranes, whereas the ideal selectivity of CO₂ to N₂ transport showed a maximum. When CO₂ is humidified, its permeability through the blend membranes is much higher than that of dry CO₂, but the change in permeability due to the presence of humidity is reversible.     

Gold nanoparticles by soft UV nanoimprint lithography coupled to a lift-off process for plasmonic sensing of antibodies

In this paper, we present the results of gold nanoparticles fabrication on large area by soft UV nanoimprint lithography (UV-NIL) and lift-off process for antibodies sensing. For this fabrication, the hard polydimethylsiloxane (H-PDMS) is used as flexible mold material. A simple AMONIL/PMMA bilayer is used to transfer patterns by etching the substrate with a suitable RIE process. The UV-NIL process has enabled to obtain gold nanoparticles with a diameter about 160 nm on a zone of 1 mm². For bioplasmonic applications, the sensing of Anti-Biotin was studied.     

Wavelength and beam launching effects on silica optical fiber in local area networks

In this paper, we report the modal dispersion of silica graded-index optical fibers as a function of the input mode parameters and lunching conditions in local area network (LAN) context. In that, we examine the mode-depending parameters, namely, modal delay, modal attenuation and mode-coupling effects as a function of wavelength. We show that the number of excited mode groups depends strongly on the spot beam radius when the fiber is excited with an axial Gaussian beam where we find an optimal axial diameter exciting only two mode groups. We present a comparison of the number of excited mode groups, the optimal spot radius beam, the signal penalty and the 3-dB baseband bandwidth enhancement for the optimal axial launching compared with full mode excitation, offset launching and mode-field matched axial launching.     

Nanoholes by soft UV nanoimprint lithography applied to study of membrane proteins

In this paper, we present an alternative technique to the well-known electron beam lithography in order to realize nanoholes in the silicon substrates for biological applications. The used technique is soft UV nanoimprint lithography (UV-NIL). We optimized the fabrication of silicon based supports obtained by soft UV-NIL and reactive ion etching to carry out very large arrays of nanoholes. The resolution limits are investigated when using poly(dimethylsiloxane) as flexible mold material. RIE conditions are initiated to limit the lateral mask resist etch.     

Metal complexes of tetradentate azo-dye ligand derived from 4,4′-oxydianiline: Preparation,structural investigation,biological evaluation and MOE studies

The Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II) and Cd (II) complexes were prepared by reaction of its metal chlorides with new azo-dye ligand (H₂L). The ligand derived from 4,4′-oxydianiline and 2-amino-4-chlorophenol was synthesized in a 1:2 molar ratio. The structure of the ligand and its metal complexes was investigated using different tools such as elemental analysis (C, H, N and M), molar conductivity, IR, UV–vis, ¹H-NMR, mass spectrometry and thermogravimetric and differential thermogravimetric studies. The data showed that the ligand acted as a N,N,O,O-binegative tetradentate ligand. All metal complexes had a octahedral structure as depicted by spectral and elemental analyses. The conductivity data showed the electrolytic nature of the Cr (III) and Fe (III) complexes while the other complexes were nonelectrolytes. Thermal analysis studies showed the decomposition of the complexes in four to five steps with the weight loss of hydrated water in the first decomposition step followed by the coordinated water and ligand molecules. Biological activity was tested for the prepared compounds against four bacterial species (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and against two fungal species (Aspergillus fumigatus and Candida albicans). Also, all complexes were screened for anticancer activities against a breast cancer (MCF-7) cell line. The [Co(L)(H₂O)₂] complex showed the lowest IC₅₀ value. Molecular docking is a key tool in computer drug design. Therefore, investigation of protein receptors and ligand interaction plays a vital role in the design of structurally based drugs. As a result, docking studies were investigated for H₂L ligand, [Mn(L)(H₂O)₂] and [Ni(L)(H₂O)₂] complexes with 5KBC, 3V7B and 4G9M receptors.     

Bioactive Tryptophan-Based Copper Complex with Auxiliary β-Carboline Spectacle Potential on Human Breast Cancer Cells: In Vitro and In Vivo Studies

Biocompatible tryptophan-derived copper (1) and zinc (2) complexes with norharmane (β-carboline) were designed, synthesized, characterized, and evaluated for the potential anticancer activity in vitro and in vivo. The in vitro cytotoxicity of both complexes 1 and 2 were assessed against two cancerous cells: (human breast cancer) MCF7 and (liver hepatocellular cancer) HepG2 cells with a non-tumorigenic: (human embryonic kidney) HEK293 cells. The results exhibited a potentially decent selectivity of 1 against MCF7 cells with an IC₅₀ value of 7.8 ± 0.4 μM compared to 2 (less active, IC₅₀ ~ 20 μM). Furthermore, we analyzed the level of glutathione, lipid peroxidation, and visualized ROS generation to get an insight into the mechanistic pathway and witnessed oxidative stress. These in vitro results were ascertained by in vivo experiments, which also supported the free radical-mediated oxidative stress. The comet assay confirmed the oxidative stress that leads to DNA damage. The histopathology of the liver also ascertained the low toxicity of 1.     

Cooperative amplify‐and‐forward partial relay selection with outdated channel information in spectrum‐sharing systems

Recently, cooperative relaying techniques have been integrated into spectrum‐sharing systems in an effort to yield higher spectral efficiency. Many investigations on such systems have assumed that the channel state information between the secondary transmitter and primary receiver used to calculate the maximum allowable transmit secondary user transmit power to limit the interference is known to be perfect. However, because of feedback delay from the primary receiver or the time‐varying properties of the channel, the channel information may be outdated, which is an important scenario to cognitive radio systems. In this paper, we investigate the impact of outdated channel state information for relay selection on the performance of partial relay selection with amplify and forward in underlay spectrum‐sharing systems. We begin by deriving a closed‐form expression for the outage probability of the secondary network in a Rayleigh fading channel along with peak received interference power constraint and maximum allowable secondary user transmit power. We also provide a closed‐form expression for the average bit‐error rate of the underlying system. Moreover, we present asymptotic expressions for both the outage probability and average bit‐error rate in the high signal‐to‐noise ratio regime that reveal practical insights on the achievable diversity gain. Finally, we confirm our results through comparisons with computer simulations. Copyright © 2016 John Wiley & Sons, Ltd.     

Immunomodulatory Efficacy-Mediated Anti-HCV and Anti-HBV Potential of Kefir Grains; Unveiling the In Vitro Antibacterial,Antifungal, and Wound Healing Activities

The utilization of fermented foods with health-promoting properties is becoming more popular around the world. Consequently, kefir, a fermented milk beverage made from kefir grains, was shown in numerous studies to be a probiotic product providing significant health benefits. Herein, we assessed the antibacterial and antifungal potential of kefir against a variety of pathogenic bacteria and fungi. This study also showed the effectiveness of kefir in healing wounds in human gastric epithelial cells (GES-1) by (80.78%) compared with control (55.75%) within 48 h. The quantitative polymerase chain reaction (qPCR) results of kefir-treated HCV- or HBV- infected cells found that 200 µg/mL of kefir can eliminate 92.36% of HCV and 75.71% of HBV relative to the untreated infected cells, whereas 800 µg/mL (the highest concentration) completely eradicated HCV and HBV. Moreover, the estimated IC₅₀ values of kefir, at which HCV and HBV were eradicated by 50%, were 63.84 ± 5.81 µg/mL and 224.02 ± 14.36 µg/mL, correspondingly. Kefir can significantly suppress the elevation of TNF-α and upregulate IL-10 and INF-γ in both treated HCV- and HBV-infected cells. High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) analysis of kefir revealed the presence of numerous active metabolites which mainly contribute to the antimicrobial, antiviral, and immunomodulatory activities. This study demonstrated, for the first time, the anti-HBV efficacy of kefir while also illustrating the immunomodulatory impact in the treated HBV-infected cells. Accordingly, kefir represents a potent antiviral agent against both viral hepatitis C and B, as well as having antimicrobial and wound healing potential.