Bioinorganic Chemistry and Applications The latest articles from Hindawi © 2018 , Hindawi Limited . All rights reserved. Synthesis, Structural Characterization, and Antibacterial Activity of Novel Erbium(III) Complex Containing Antimony Tue, 20 Mar 2018 00:00:00 +0000 The novel 3D edta-linked heterometallic complex [Sb2Er(edta)2(H2O)4]NO3·4H2O (H4edta = ethylenediaminetetraacetic acid) was synthesized and characterized by elemental analyses, single-crystal X-ray diffraction, powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal analysis. The complex crystallizes in the monoclinic system with space group Pm. In the complex, each erbium(III) ion is connected with antimony(III) ions bridging by four carboxylic oxygen atoms, and in each [Sb(edta)]− anion, the antimony(III) ion is hexacoordinated by two nitrogen atoms and four oxygen atoms from the edta4− ions, together with a lone electron pair at the equatorial position. The erbium(III) ion is octacoordinated by four oxygen atoms from four different edta4− ions and four oxygen atoms from the coordinated water molecules. The carboxylate bridges between antimony and erbium atoms form a planar array, parallel to the (1 0 0) plane. There is an obvious weak interaction between antimony atom and oxygen atom of the carboxyl group from the adjacent layer. The degradation of the complex proceeds in several steps and the water molecules and ligands are successively emitted, and the residues of the thermal decomposition are antimonous oxide and erbium(III) oxide. The complex was evaluated for its antimicrobial activities by agar diffusion method, and it has good activities against the test bacterial organisms. Ting Liu, Rong-Gui Yang, and Guo-Qing Zhong Copyright © 2018 Ting Liu et al. All rights reserved. Synthesis, Characterization, and BSA-Binding Studies of Novel Sulfonated Zinc-Triazine Complexes Sun, 18 Feb 2018 00:00:00 +0000 Four Zn(II) complexes containing a pyridyl triazine core (L1 = 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5′,5″-disulfonic acid disodium salt and L2 = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4′,4″-disulfonic acid sodium salt) were synthesized, and their chemical formulas were finalized as [Zn(L1)Cl2]·5H2O·ZnCl2 (1), [Zn(L1)2Cl2]·4H2O·2CH3OH (2), [Zn(L2)Cl2]·3H2O·CH3OH (3), and [Zn(L2)2Cl2] (4). The synthesized complexes are water soluble, making them good candidates for biological applications. All four complexes have been characterized by elemental analysis and 1H NMR, IR, and UV-Vis spectroscopy. The IR stretching frequency of N=N and C=N bonds of complexes 1–4 have shifted to lower frequencies in comparison with free ligands, and a bathochromic shift was observed in UV-Vis spectra of all four complexes. The binding studies of ligands and complexes 1–4 with bovine serum albumin (BSA) resulted binding constants (Kb) of 3.09 × 104 M−1, 12.30 × 104 M−1, and 16.84 × 104 M−1 for ferene, complex 1, and complex 2, respectively, indicating potent serum distribution via albumins. Nalin Abeydeera, Inoka C. Perera, and Theshini Perera Copyright © 2018 Nalin Abeydeera et al. All rights reserved. Chemical Composition and Porosity Characteristics of Various Calcium Silicate-Based Endodontic Cements Thu, 01 Feb 2018 00:00:00 +0000 Chemical composition and porosity characteristics of calcium silicate-based endodontic cements are important determinants of their clinical performance. Therefore, the aim of this study was to investigate the chemical composition and porosity characteristics of various calcium silicate-based endodontic cements: MTA-angelus, Bioaggregate, Biodentine, Micromega MTA, Ortho MTA, and ProRoot MTA. The specific surface area, pore volume, and pore diameter were measured by the porosimetry analysis of N2 adsorption/desorption isotherms. Chemical composition and powder analysis by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were also carried out on these endodontic cements. Biodentine and MTA-angelus showed the smallest pore volume and pore diameter, respectively. Specific surface area was the largest in MTA-angelus. SEM and EDS analysis showed that Bioaggregate and Biodentine contained homogenous, round and small particles, which did not contain bismuth oxide. Seok Woo Chang Copyright © 2018 Seok Woo Chang. All rights reserved. Structural Basis for pH-Dependent Oligomerization of Dihydropyrimidinase from Pseudomonas aeruginosa PAO1 Tue, 30 Jan 2018 06:17:33 +0000 Dihydropyrimidinase, a dimetalloenzyme containing a carboxylated lysine within the active site, is a member of the cyclic amidohydrolase family, which also includes allantoinase, dihydroorotase, hydantoinase, and imidase. Unlike all known dihydropyrimidinases, which are tetrameric, pseudomonal dihydropyrimidinase forms a dimer at neutral pH. In this paper, we report the crystal structure of P. aeruginosa dihydropyrimidinase at pH 5.9 (PDB entry 5YKD). The crystals of P. aeruginosa dihydropyrimidinase belonged to space group C2221 with cell dimensions of a = 108.9, b = 155.7, and c = 235.6 Å. The structure of P. aeruginosa dihydropyrimidinase was solved at 2.17 Å resolution. An asymmetric unit of the crystal contained four crystallographically independent P. aeruginosa dihydropyrimidinase monomers. Gel filtration chromatographic analysis of purified P. aeruginosa dihydropyrimidinase revealed a mixture of dimers and tetramers at pH 5.9. Thus, P. aeruginosa dihydropyrimidinase can form a stable tetramer both in the crystalline state and in the solution. Based on sequence analysis and structural comparison of the dimer-dimer interface between P. aeruginosa dihydropyrimidinase and Thermus sp. dihydropyrimidinase, different oligomerization mechanisms are proposed. Jen-Hao Cheng, Chien-Chih Huang, Yen-Hua Huang, and Cheng-Yang Huang Copyright © 2018 Jen-Hao Cheng et al. All rights reserved. Adsorption Characteristics of Bixin on Acid- and Alkali-Treated Kaolinite in Aprotic Solvents Thu, 18 Jan 2018 00:00:00 +0000 The adsorption of bixin in aprotic solvents onto acid- and alkali-treated kaolinite was investigated. Kaolinite was treated three times, for 6 h each, with 8 M HCl or 5 M KOH. The adsorbents were characterized by XRD, FT-IR, EDS, and BET-N2. The effects of contact time and dye concentration on adsorption capacity and kinetics, electronic transition of bixin before and after adsorption, and also mechanism of bixin-kaolinite adsorption were investigated. Dye adsorption followed pseudo-second order kinetics and was faster in acetone than in dimethyl carbonate. The best adsorption results were obtained for KOH-treated kaolinite. In both of the solvents, the adsorption isotherm followed the Langmuir model and adsorption capacity was higher in dimethyl carbonate (qm = 0.43 mg/g) than in acetone (0.29 mg/g). The adsorption capacity and kinetics of KOH-treated kaolinite (qm = 0.43 mg/g, k2 = 3.27 g/mg·min) were better than those of HCl-treated kaolinite (qm = 0.21 mg/g, k2 = 0.25 g/mg·min) and natural kaolinite (qm = 0.18 mg/g, k2 = 0.32 g/mg·min). There are shift in the band position of maximum intensity of bixin after adsorption on this adsorbent. Adsorption in this system seemed to be based essentially on chemisorption due to the electrostatic interaction of bixin with the strong basic and reducing sites of kaolinite. Winda Rahmalia, Jean-François Fabre, Thamrin Usman, and Zéphirin Mouloungui Copyright © 2018 Winda Rahmalia et al. All rights reserved. Co(II) Coordination in Prokaryotic Zinc Finger Domains as Revealed by UV-Vis Spectroscopy Thu, 14 Dec 2017 09:01:34 +0000 Co(II) electronic configuration allows its use as a spectroscopic probe in UV-Vis experiments to characterize the metal coordination sphere that is an essential component of the functional structure of zinc-binding proteins and to evaluate the metal ion affinities of these proteins. Here, exploiting the capability of the prokaryotic zinc finger to use different combinations of residues to properly coordinate the structural metal ion, we provide the UV-Vis characterization of Co(II) addition to Ros87 and its mutant Ros87_C27D which bears an unusual CysAspHis2 coordination sphere. Zinc finger sites containing only one cysteine have been infrequently characterized. We show for the CysAspHis2 coordination an intense d-d transition band, blue-shifted with respect to the Cys2His2 sphere. These data complemented by NMR and CD data demonstrate that the tetrahedral geometry of the metal site is retained also in the case of a single-cysteine coordination sphere. Valeria Sivo, Gianluca D’Abrosca, Luigi Russo, Rosa Iacovino, Paolo Vincenzo Pedone, Roberto Fattorusso, Carla Isernia, and Gaetano Malgieri Copyright © 2017 Valeria Sivo et al. All rights reserved. Synthesis and Cytotoxic Evaluation of Steroidal Copper (Cu (II)) Complexes Wed, 18 Oct 2017 08:46:49 +0000 Using estrone and pregnenolone as starting materials, some steroidal copper complexes were synthesized by the condensation of steroidal ketones with thiosemicarbazide or diazanyl pyridine and then complexation of steroidal thiosemicarbazones or steroidal diazanyl pyridines with Cu (II). The complexes were characterized by IR, NMR, and HRMS. The synthesized compounds were screened for their cytotoxicity against HeLa, Bel-7404, and 293T cell lines in vitro. The results show that all steroidal copper (II) complexes display obvious antiproliferative activity against the tested cancer cells. The IC50 values of complexes 5 and 12 against Bel-7404 (human liver carcinoma) are 5.0 and 7.0 μM. Yanmin Huang, Erbin Kong, Junyan Zhan, Shuang Chen, Chunfang Gan, Zhiping Liu, Liping Pang, and Jianguo Cui Copyright © 2017 Yanmin Huang et al. All rights reserved. Synthesis, Characterization, Cytotoxic Activity, and Interactions with CT-DNA and BSA of Cationic Ruthenium(II) Complexes Containing Dppm and Quinoline Carboxylates Wed, 26 Jul 2017 07:23:56 +0000 The complexes cis-[Ru(quin)(dppm)2]PF6 and cis-[Ru(kynu)(dppm)2]PF6 (quin = quinaldate; kynu = kynurenate; dppm = bis(diphenylphosphino)methane) were prepared and characterized by elemental analysis, electronic, FTIR, 1H, and 31P NMR spectroscopies. Characterization data were consistent with a cis arrangement for the dppm ligands and a bidentate coordination through carboxylate oxygens of the quin and kynu anions. These complexes were not able to intercalate CT-DNA as shown by circular dichroism spectroscopy. On the other hand, bovine serum albumin (BSA) binding constants and thermodynamic parameters suggest spontaneous interactions with this protein by hydrogen bonds and van der Waals forces. Cytotoxicity assays were carried out on a panel of human cancer cell lines including HepG2, MCF-7, and MO59J and one normal cell line GM07492A. In general, the new ruthenium(II) complexes displayed a moderate to high cytotoxicity in all the assayed cell lines with IC50 ranging from 10.1 to 36 µM and were more cytotoxic than the precursor cis-[RuCl2(dppm)2]. The cis-[Ru(quin)(dppm)2]PF6 were two to three times more active than the reference metallodrug cisplatin in the MCF-7 and MO59J cell lines. Edinaldo N. da Silva, Paulo A. B. da Silva, Angélica E. Graminha, Pollyanna F. de Oliveira, Jaqueline L. Damasceno, Denise C. Tavares, Alzir A. Batista, and Gustavo Von Poelhsitz Copyright © 2017 Edinaldo N. da Silva et al. All rights reserved. Bioactive Potential of 3D-Printed Oleo-Gum-Resin Disks: B. papyrifera, C. myrrha, and S. benzoin Loading Nanooxides—TiO2, P25, Cu2O, and MoO3 Tue, 25 Jul 2017 09:20:32 +0000 This experimental study investigates the bioactive potential of filaments produced via hot melt extrusion (HME) and intended for fused deposition modeling (FDM) 3D printing purposes. The oleo-gum-resins from benzoin, myrrha, and olibanum in pure state and also charged with 10% of metal oxide nanoparticles, TiO2, P25, Cu2O, and MoO3, were characterized by ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray microanalysis (EDXMA), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Disks were 3D-printed into model geometries (10 × 5 mm) and the disk-diffusion methodology was used for the evaluation of antimicrobial and antifungal activity of materials in study against the clinical isolates: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. Due to their intrinsic properties, disks containing resins in pure state mostly prevent surface-associated growth; meanwhile, disks loaded with 10% oxides prevent planktonic growth of microorganisms in the susceptibility assay. The microscopy analysis showed that part of nanoparticles was encapsulated by the biopolymeric matrix of resins, in most cases remaining disorderly dispersed over the surface of resins. Thermal analysis shows that plant resins have peculiar characteristics, with a thermal behavior similar to commercial available semicrystalline polymers, although their structure consists of a mix of organic compounds. Diogo José Horst, Sergio Mazurek Tebcherani, Evaldo Toniolo Kubaski, and Rogério de Almeida Vieira Copyright © 2017 Diogo José Horst et al. All rights reserved. Influence of the Number of Axial Bexarotene Ligands on the Cytotoxicity of Pt(IV) Analogs of Oxaliplatin Wed, 19 Jul 2017 07:58:21 +0000 We present the synthesis and cytotoxic potencies of new Pt(IV) complexes with bexarotene, an anticancer drug that induces cell differentiation and apoptosis via selective activation of retinoid X receptors. In these complexes bexarotene is positioned as an axial ligand. The complex of one bexarotene ligand attached to Pt(IV) oxaliplatin moiety was potent whereas its counterpart carrying two bexarotene ligands was inactive. Yulia N. Nosova, Ilia V. Zenin, Varvara P. Maximova, Ekaterina M. Zhidkova, Kirill I. Kirsanov, Ekaterina A. Lesovaya, Anna A. Lobas, Mikhail V. Gorshkov, Olga N. Kovaleva, Elena R. Milaeva, Markus Galanski, Bernhard K. Keppler, and Alexey A. Nazarov Copyright © 2017 Yulia N. Nosova et al. All rights reserved. Metals in the Environment: Toxic Metals Removal Sun, 16 Jul 2017 00:00:00 +0000 Muataz A. Atieh, Yun Ji, and Viktor Kochkodan Copyright © 2017 Muataz A. Atieh et al. All rights reserved. A DFT Study of Structural and Bonding Properties of Complexes Obtained from First-Row Transition Metal Chelation by 3-Alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-one and Its Derivatives Mon, 03 Jul 2017 09:17:01 +0000 Density functional calculations were used to explore the complexation of 3-alkyl-4-phenylacetylamino-4,5-dihydro-1h-1,2,4-triazol-5-one (ADPHT) derivatives by first-row transition metal cations. Neutral ADPHT ligand and mono deprotonated ligands have been used. Geometry optimizations have been performed in gas-phase and solution-phase (water, benzene, and N,N-dimethylformamide (DMF)) with B3LYP/Mixed I (LanL2DZ for metal atom and 6-31+G(d,p) for C, N, O, and H atoms) and with B3LYP/Mixed II (6-31G(d) for metal atom and 6-31+G(d,p) for C, N, O, and H atoms) especially in the gas-phase. Single points have also been carried out at CCSD(T) level. The B3LYP/Mixed I method was used to calculate thermodynamic energies (energies, enthalpies, and Gibb energies) of the formation of the complexes analyzed. The B3LYP/Mixed I complexation energies in the gas phase are therefore compared to those obtained using B3LYP/Mixed II and CCSD(T) calculations. Our results pointed out that the deprotonation of the ligand increases the binding affinity independently of the metal cation used. The topological parameters yielded from Quantum Theory of Atom in Molecules (QTAIM) indicate that metal-ligand bonds are partly covalent. The significant reduction of the proton affinity (PA) observed when passing from ligands to complexes in gas-phase confirms the notable enhancement of antioxidant activities of neutral ligands. Hubert Jean Nono, Désiré Bikélé Mama, Julius Numbonui Ghogomu, and Elie Younang Copyright © 2017 Hubert Jean Nono et al. All rights reserved. A QSAR Study Based on SVM for the Compound of Hydroxyl Benzoic Esters Mon, 03 Jul 2017 06:31:48 +0000 Hydroxyl benzoic esters are preservative, being widely used in food, medicine, and cosmetics. To explore the relationship between the molecular structure and antibacterial activity of these compounds and predict the compounds with similar structures, Quantitative Structure-Activity Relationship (QSAR) models of 25 kinds of hydroxyl benzoic esters with the quantum chemical parameters and molecular connectivity indexes are built based on support vector machine (SVM) by using R language. The External Standard Deviation Error of Prediction (), fitting correlation coefficient (), and leave-one-out cross-validation () are used to value the reliability, stability, and predictive ability of models. The results show that and of 4 kinds of nonlinear models are more than 0.6 and is 0.213, 0.222, 0.189, and 0.218, respectively. Compared with the multiple linear regression (MLR) model (, RSD = 0.260), the correlation coefficient and the standard deviation are both better than MLR. The reliability, stability, robustness, and external predictive ability of models are good, particularly of the model of linear kernel function and eps-regression type. This model can predict the antimicrobial activity of the compounds with similar structure in the applicability domain. Li Wen, Qing Li, Wei Li, Qiao Cai, and Yong-Ming Cai Copyright © 2017 Li Wen et al. All rights reserved. Metal Complexes of a Novel Schiff Base Based on Penicillin: Characterization, Molecular Modeling, and Antibacterial Activity Study Thu, 08 Jun 2017 00:00:00 +0000 A novel Schiff base ligand of type HL was prepared by the condensation of amoxicillin trihydrate and nicotinaldehyde. The metal complexes of Co+2, Ni+2, Cu+2, and Zn+2 were characterized and investigated by physical and spectral techniques, namely, elemental analysis, melting point, conductivity, 1H NMR, IR, UV-Vis spectra, ESR, SEM, and mass spectrometry measurements. They were further analyzed by thermal technique (TGA/DTA) to gain better insight about the thermal stability and kinetic properties of the complexes. Thermal data revealed high thermal stability and nonspontaneous nature of the decomposition steps. The Coats-Redfern method was applied to extract thermodynamic parameters to explain the kinetic behavior. The molar conductance values were relatively low, showing their nonelectrolytic nature. The powder XRD pattern revealed amorphous nature except copper complex (1c) that crystallized in the triclinic crystal system. The EPR study strongly recommends the tetrahedral geometry of 1c. The structure optimization by MM force field calculation through ArgusLab 4.0.1 software program supports the concerned geometry of the complexes. The in vitro antibacterial activity of all the compounds, at their two different concentrations, was screened against four bacterial pathogens, namely, E. coli, P. vulgaris, K. pneumoniae, and S. aureus, and showed better activity compared to parent drug and control drug. Narendra Kumar Chaudhary and Parashuram Mishra Copyright © 2017 Narendra Kumar Chaudhary and Parashuram Mishra. All rights reserved. Cadmium Removal from Contaminated Water Using Polyelectrolyte-Coated Industrial Waste Fly Ash Wed, 07 Jun 2017 00:00:00 +0000 Fly ash (FA) is a major industrial waste generated from power stations that add extra cost for proper disposal. Recent research efforts have consequently focused on developing ways to make use of FA in environmentally sound applications. This study, therefore, investigates the potential ability of raw fly ash (RFA) and polyelectrolyte-coated fly ash (PEFA) to remove cadmium (Cd) from polluted water. Using layer-by-layer approach, functionalized fly ash was coated with 20 layers from 0.03% (v/v) of cationic poly(diallyldimethylammonium chloride) (PDADMAC) and anionic polystyrene sulfonate (PSS) solutions. Both surface morphology and chemical composition of the adsorbent (PEFA) were characterized using Field-Emission Scanning Electron Microscope (FE-SEM), X-Ray Diffraction (XRD), Fourier-Transform Infrared (FTIR), and X-Ray Fluorescence (XRF) techniques. The effects of pH, adsorbent dosage, contact time, initial contaminant concentration, and mixing rate of the adsorption of Cd were also studied in batch mode experiments. Results of the study revealed that a 4.0 g/L dosage of PEFA removed around 99% of 2.0 mg/L of Cd in 15 min at 150 rpm compared to only 27% Cd removal achieved by RFA under the same conditions. Results also showed that adsorption by PEFA followed both Langmuir and Freundlich models with correlation coefficients of 98% and 99%, respectively. Fatai A. Olabemiwo, Bassam S. Tawabini, Faheemuddin Patel, Tajudeen A. Oyehan, Mazen Khaled, and Tahar Laoui Copyright © 2017 Fatai A. Olabemiwo et al. All rights reserved. Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes Sun, 07 May 2017 00:00:00 +0000 The aim of this research was to investigate the potential of raw and iron oxide impregnated carbon nanotubes (CNTs) as adsorbents for the removal of selenium (Se) ions from wastewater. The original and modified CNTs with different loadings of Fe2O3 nanoparticles were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), Brunauer, Emmett, and Teller (BET) surface area analyzer, thermogravimetric analysis (TGA), zeta potential, and energy dispersive X-ray spectroscopy (EDS). The adsorption parameters of the selenium ions from water using raw CNTs and iron oxide impregnated carbon nanotubes (CNT-Fe2O3) were optimized. Total removal of 1 ppm Se ions from water was achieved when 25 mg of CNTs impregnated with 20 wt.% of iron oxide nanoparticles is used. Freundlich and Langmuir isotherm models were used to study the nature of the adsorption process. Pseudo-first and pseudo-second-order models were employed to study the kinetics of selenium ions adsorption onto the surface of iron oxide impregnated CNTs. Maximum adsorption capacity of the Fe2O3 impregnated CNTs, predicted by Langmuir isotherm model, was found to be 111 mg/g. This new finding might revolutionize the adsorption treatment process and application by introducing a new type of nanoadsorbent that has super adsorption capacity towards Se ions. Omer Y. Bakather, Ahmad Kayvani Fard, Ihsanullah, Majeda Khraisheh, Mustafa S. Nasser, and Muataz Ali Atieh Copyright © 2017 Omer Y. Bakather et al. All rights reserved. The Effect of Hydrofluoric Acid Surface Treatment on the Cyclic Fatigue Resistance of K3 NiTi Instruments Tue, 02 May 2017 09:18:21 +0000 The aim of this study was to investigate the effect of 50% hydrofluoric acid (HF) surface treatment on the cyclic fatigue resistance (CFR) of K3 NiTi instruments. Twenty as-received and twenty HF-treated K3 NiTi instruments were compared in CFR. The surface texture and fracture surface of two instrument groups were examined with a scanning electron microscope (SEM). Additionally, any change of Ni and Ti composition from both instrument groups was investigated using energy dispersive spectrometry. The results were analyzed with -test. The HF-treated K3 group showed statistically higher cyclic fatigue resistance than as-received K3 group (). HF-treated K3 instruments showed smoother and rounded surface compared to as-received K3 under SEM observation. The fracture surfaces of both groups showed typical patterns of cyclic fatigue fracture. There was no difference in surface Ni and Ti composition between two groups. HF treatment of K3 instruments smoothed the file surface and increased the cyclic fatigue resistance, while it had no effect on surface ion composition and the file fracture pattern. Kee-Yeon Kum and Seok Woo Chang Copyright © 2017 Kee-Yeon Kum and Seok Woo Chang. All rights reserved. A Comparative Study of Raw and Metal Oxide Impregnated Carbon Nanotubes for the Adsorption of Hexavalent Chromium from Aqueous Solution Mon, 10 Apr 2017 00:00:00 +0000 The present study reports the use of raw, iron oxide, and aluminum oxide impregnated carbon nanotubes (CNTs) for the adsorption of hexavalent chromium (Cr(VI)) ions from aqueous solution. The raw CNTs were impregnated with 1% and 10% loadings (weight %) of iron oxide and aluminum oxide nanoparticles using wet impregnation technique. The synthesized materials were characterized using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Batch adsorption experiments were performed to assess the removal efficiency of Cr(VI) ions from water and the effects of pH, contact time, adsorbent dosage, and initial concentration of the Cr(VI) ions were investigated. Results of the study revealed that impregnated CNTs achieved significant increase in the removal efficiency of Cr(VI) ions compared to raw CNTs. In fact, both CNTs impregnated with 10% loading of iron and aluminum oxides were able to remove up to 100% of Cr(VI) ions from aqueous solution. Isotherm studies were carried out using Langmuir and Freundlich isotherm models. Adsorption kinetics of Cr(VI) ions from water was found to be well described by the pseudo-second-order model. The results suggest that metallic oxide impregnated CNTs have very good potential application in the removal of Cr(VI) ions from water resulting in better environmental protection. Muhammad I. Qureshi, Faheemuddin Patel, Nadhir Al-Baghli, Basim Abussaud, Bassam S. Tawabini, and Tahar Laoui Copyright © 2017 Muhammad I. Qureshi et al. All rights reserved. A Review on Platelet Activating Factor Inhibitors: Could a New Class of Potent Metal-Based Anti-Inflammatory Drugs Induce Anticancer Properties? Tue, 28 Mar 2017 00:00:00 +0000 In this minireview, we refer to recent results as far as the Platelet Activating Factor (PAF) inhibitors are concerned. At first, results of organic compounds (natural and synthetic ones and specific and nonspecific) as inhibitors of PAF are reported. Emphasis is given on recent results about a new class of the so-called metal-based inhibitors of PAF. A small library of 30 metal complexes has been thus created; their anti-inflammatory activity has been further evaluated owing to their inhibitory effect against PAF in washed rabbit platelets (WRPs). In addition, emphasis has also been placed on the identification of preliminary structure-activity relationships for the different classes of metal-based inhibitors. Vasiliki D. Papakonstantinou, Nefeli Lagopati, Effie C. Tsilibary, Constantinos A. Demopoulos, and Athanassios I. Philippopoulos Copyright © 2017 Vasiliki D. Papakonstantinou et al. All rights reserved. Removal of Zinc from Aqueous Solution by Optimized Oil Palm Empty Fruit Bunches Biochar as Low Cost Adsorbent Tue, 21 Mar 2017 10:19:30 +0000 This study aims to produce optimized biochar from oil palm empty fruit bunches (OPEFB), as a green, low cost adsorbent for uptake of zinc from aqueous solution. The impact of pyrolysis conditions, namely, highest treatment temperature (HTT), heating rate (HR), and residence time (RT) on biochar yield and adsorption capacity towards zinc, was investigated. Mathematical modeling and optimization of independent variables were performed employing response surface methodology (RSM). HTT was found to be the most influential variable, followed by residence time and heating rate. Based on the central composite design (CCD), two quadratic models were developed to correlate three independent variables to responses. The optimum production condition for OPEFB biochar was found as follows: HTT of 615°C, HR of 8°C/min, and RT of 128 minutes. The optimum biochar showed 15.18 mg/g adsorption capacity for zinc and 25.49% of yield which was in agreement with the predicted values, satisfactory. Results of the characterization of optimum product illustrated well-developed BET surface area and porous structure in optimum product which favored its sorptive ability. Seyed Ali Zamani, Robiah Yunus, A. W. Samsuri, M. A. Mohd Salleh, and Bahareh Asady Copyright © 2017 Seyed Ali Zamani et al. All rights reserved. Adsorption of Toluene and Paraxylene from Aqueous Solution Using Pure and Iron Oxide Impregnated Carbon Nanotubes: Kinetics and Isotherms Study Sun, 12 Mar 2017 00:00:00 +0000 Multiwall carbon nanotubes (CNTs) and iron oxide impregnated carbon nanotubes (CNTs-iron oxide) were investigated for the adsorption of hazardous toluene and paraxylene (p-xylene) from aqueous solution. Pure CNTs were impregnated with iron oxides nanoparticles using wet impregnation technique. Various characterization techniques including thermogravimetric analysis, scanning electron microscopy, elemental dispersion spectroscopy, X-ray diffraction, and nitrogen adsorption analysis were used to study the thermal degradation, surface morphology, purity, and surface area of the materials. Batch adsorption experiments show that iron oxide impregnated CNTs have higher degree of removal of p-xylene (i.e., 90%) compared with toluene (i.e., 70%), for soaking time 2 h, with pollutant initial concentration 100 ppm, at pH 6 and shaking speed of 200 rpm at 25°C. Pseudo-second-order model provides better fitting for the toluene and p-xylene adsorption. Langmuir and Freundlich isotherm models demonstrate good fitting for the adsorption data of toluene and p-xylene. Aamir Abbas, Basim Ahmed Abussaud, Ihsanullah, Nadhir A. H. Al-Baghli, and Halim Hamid Redhwi Copyright © 2017 Aamir Abbas et al. All rights reserved. Hazardous Effects of Titanium Dioxide Nanoparticles in Ecosystem Wed, 08 Mar 2017 00:00:00 +0000 Although nanoparticles (NPs) have made incredible progress in the field of nanotechnology and biomedical research and their applications are demanded throughout industrial world particularly over the past decades, little is known about the fate of nanoparticles in ecosystem. Concerning the biosafety of nanotechnology, nanotoxicity is going to be the second most priority of nanotechnology that needs to be properly addressed. This review covers the chemical as well as the biological concerns about nanoparticles particularly titanium dioxide (TiO2) NPs and emphasizes the toxicological profile of TiO2 at the molecular level in both in vitro and in vivo systems. In addition, the challenges and future prospects of nanotoxicology are discussed that may provide better understanding and new insights into ongoing and future research in this field. Syed Niaz Ali Shah, Zahir Shah, Muzammal Hussain, and Muzaffar Khan Copyright © 2017 Syed Niaz Ali Shah et al. All rights reserved. Equilibrium, Kinetic, and Thermodynamic Studies on the Adsorption of Cadmium from Aqueous Solution by Modified Biomass Ash Tue, 28 Feb 2017 08:52:36 +0000 Natural biomass ash of agricultural residuals was collected from a power plant and modified with hexagonal mesoporous silica and functionalized with 3-aminopropyltriethoxysilane. The physicochemical and morphological properties of the biomass ash were analyzed by ICP-OES, SEM, TEM-EDS, FTIR, and BET analysis. The adsorption behavior of the modified product for Cd2+ in aqueous solution was studied as a function of pH, initial metal concentration, equilibrium time, and temperature. Results showed that the specific surface area of the modified product was 9 times that of the natural biomass ash. The modified biomass ash exhibited high affinity for Cd2+ and its adsorption capacity increased sharply with increasing pH from 4.0 to 6.0. The maximum adsorption capacity was 23.95 mg/g in a pH 5 solution with an initial metal concentration of 50 mg/L and a contact time of 90 min. The adsorption of Cd2+ onto the modified biomass ash was well fitted to the Langmuir model and it followed pseudo-second-order kinetics. Thermodynamic analysis results showed that the adsorption of Cd2+ was spontaneous and endothermic in nature. The results suggest that the modified biomass ash is promising for use as an inexpensive and effective adsorbent for Cd2+ removal from aqueous solution. Lei Xu, Xuebo Zheng, Hongbiao Cui, Zhenqiu Zhu, Jiani Liang, and Jing Zhou Copyright © 2017 Lei Xu et al. All rights reserved. X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex Sun, 19 Feb 2017 00:00:00 +0000 In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed. Finally, a computational approach was performed in order to obtain a detailed and precise insight of product structures and properties. It is hoped that this study can enrich the field of functional supramolecular systems, giving place to the formation of coordination-driven self-assembly architectures. Dimitrios Matiadis, Dimitrios Tsironis, Valentina Stefanou, Olga Igglessi–Markopoulou, Vickie McKee, Yiannis Sanakis, Katerina N. Lazarou, Athanassios Chrissanthopoulos, Spyros N. Yannopoulos, and John M. Markopoulos Copyright © 2017 Dimitrios Matiadis et al. All rights reserved. Syntheses, Characterization, Resolution, and Biological Studies of Coordination Compounds of Aspartic Acid and Glycine Wed, 15 Feb 2017 00:00:00 +0000 Enantiomerically enriched coordination compounds of aspartic acid and racemic mixtures of coordination compounds of glycine metal-ligand ratio 1 : 3 were synthesized and characterized using infrared and UV-Vis spectrophotometric techniques and magnetic susceptibility measurements. Five of the complexes were resolved using (+)-cis-dichlorobis(ethylenediamine)cobalt(III) chloride, (+)-bis(glycinato)(1,10-phenanthroline)cobalt(III) chloride, and (+)-tris(1,10-phenanthroline)nickel(II) chloride as resolving agents. The antimicrobial and cytotoxic activities of these complexes were then determined. The results obtained indicated that aspartic acid and glycine coordinated in a bidentate fashion. The enantiomeric purity of the compounds was in the range of 22.10–32.10%, with (+)-cis-dichlorobis(ethylenediamine)cobalt(III) complex as the more efficient resolving agent. The resolved complexes exhibited better activity in some cases compared to the parent complexes for both biological activities. It was therefore inferred that although the increase in the lipophilicity of the complexes may assist in the permeability of the complexes through the cell membrane of the pathogens, the enantiomeric purity of the complexes is also of importance in their activity as antimicrobial and cytotoxic agents. Temitayo Aiyelabola, Ezekiel Akinkunmi, Isaac Ojo, Efere Obuotor, Clement Adebajo, and David Isabirye Copyright © 2017 Temitayo Aiyelabola et al. All rights reserved. Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract Mon, 13 Feb 2017 00:00:00 +0000 This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used. I. DeAlba-Montero, Jesús Guajardo-Pacheco, Elpidio Morales-Sánchez, Rene Araujo-Martínez, G. M. Loredo-Becerra, Gabriel-Alejandro Martínez-Castañón, Facundo Ruiz, and M. E. Compeán Jasso Copyright © 2017 I. DeAlba-Montero et al. All rights reserved. Synthesis Characterization and Biological Activities of Coordination Compounds of 4-Hydroxy-3-nitro-2H-chromen-2-one and Its Aminoethanoic Acid and Pyrrolidine-2-carboxylic Acid Mixed Ligand Complexes Tue, 07 Feb 2017 08:21:34 +0000 Coordination compounds of 4-hydroxy-3-nitro-2H-chromen-2-one and their mixed ligand complexes with aminoethanoic acid and pyrrolidine-2-carboxylic acid were synthesized by the reaction of Cu(II) and Zn(II) salts in molar ratio 1 : 2 for the coumarin complexes and 1 : 1 : 1 for the mixed ligand complexes, in basic media. The compounds formed were characterized using infrared, Uv-vis spectrophotometric analyses, mass spectrometry, magnetic susceptibility measurements, and EDX analyses. It was concluded that 4-hydroxy-3-nitro-2H-chromen-2-one coordinated as a monobasic ligand for all the complexes; it also coordinated via the carbonyl moiety in the case of the Cu(II) mixed ligand complexes. Similarly it was proposed that the amino acids also coordinated in a bidentate fashion via their amino nitrogen and carboxylate oxygen atoms. The synthesized compounds were screened for their antimicrobial and cytotoxic activities. The complexes exhibited marginal antimicrobial activity but good cytotoxic activity. Temitayo Aiyelabola, Ezekiel Akinkunmi, Efere Obuotor, Idowu Olawuni, David Isabirye, and Johan Jordaan Copyright © 2017 Temitayo Aiyelabola et al. All rights reserved. Physicochemical Properties of Epoxy Resin-Based and Bioceramic-Based Root Canal Sealers Sun, 22 Jan 2017 00:00:00 +0000 Three bioceramic sealers (EndoSequence BC sealer, EndoSeal MTA, and MTA Fillapex) and three epoxy resin-based sealers (AH-Plus, AD Seal, and Radic-Sealer) were tested to evaluate the physicochemical properties: flow, final setting time, radiopacity, dimensional stability, and pH change. The one-way ANOVA and Tukey’s post hoc test were used to analyze the data (). The MTA Fillapex sealer had a highest flow and the BC Sealer presented a flow significantly lower than the others (). The BC Sealer and MTA Fillapex samples were not set in humid incubator condition even after one month. EndoSeal MTA had the longest setting time among the measurable materials and Radic-Sealer and AD Seal showed shorter setting time than the AH-Plus (). AH-Plus and EndoSeal MTA showed statistically higher values and MTA Fillapex showed statistically lower radiopacity (). BC Sealer showed the highest alkaline pH in all evaluation periods. Set samples of 3 epoxy resin-based sealers and EndoSeal MTA presented a significant increase of pH over experimental time for 4 weeks. In conclusion, the bioceramic sealer and epoxy resin-based sealers showed clinical acceptable physicochemical properties, but BC Sealer and MTA Fillapex were not set completely. Ju Kyung Lee, Sang Won Kwak, Jung-Hong Ha, WooCheol Lee, and Hyeon-Cheol Kim Copyright © 2017 Ju Kyung Lee et al. All rights reserved. Establishment of a Method for Measuring Antioxidant Capacity in Urine, Based on Oxidation Reduction Potential and Redox Couple I2/KI Tue, 27 Dec 2016 08:55:07 +0000 Objectives. To establish a new method for determination of antioxidant capacity of human urine based on the redox couple I2/KI and to evaluate the redox status of healthy and diseased individuals. Methods. The method was based on the linear relationship between oxidation reduction potential (ORP) and logarithm of concentration ratio of I2/KI. ORP of a solution with a known concentration ratio of I2/KI will change when reacted with urine. To determine the accuracy of the method, both vitamin C and urine were reacted separately with I2/KI solution. The new method was compared with the traditional method of iodine titration and then used to measure the antioxidant capacity of urine samples from 30 diabetic patients and 30 healthy subjects. Results. A linear relationship was found between logarithm of concentration ratio of I2/KI and ORP (). Both vitamin C and urine concentration showed a linear relationship with ORP ( and 0.986, resp.). The precision of the method was in the acceptable range and results of two methods had a linear correlation (). Differences in ORP values between diabetic group and control group were statistically significant (). Conclusions. A new method for measuring the antioxidant capacity of clinical urine has been established. Tinghui Cao, Min He, Tianyu Bai, and Hui Liu Copyright © 2016 Tinghui Cao et al. All rights reserved. The Role of Metals in the Reaction Catalyzed by Metal-Ion-Independent Bacillary RNase Wed, 21 Dec 2016 06:49:27 +0000 Extracellular enzymes of intestinal microbiota are the key agents that affect functional activity of the body as they directly interact with epithelial and immune cells. Several species of the Bacillus genus, like Bacillus pumilus, a common producer of extracellular RNase binase, can populate the intestinal microbiome as a colonizing organism. Without involving metal ions as cofactors, binase depolymerizes RNA by cleaving the 3′,5′-phosphodiester bond and generates 2′,3′-cyclic guanosine phosphates in the first stage of a catalytic reaction. Maintained in the reaction mixture for more than one hour, such messengers can affect the human intestinal microflora and the human body. In the present study, we found that the rate of 2′,3′-cGMP was growing in the presence of transition metals that stabilized the RNA structure. At the same time, transition metal ions only marginally reduced the amount of 2′,3′-cGMP, blocking binase recognition sites of guanine at N7 of nucleophilic purine bases. Yulia Sokurenko, Vera Ulyanova, Pavel Zelenikhin, Alexey Kolpakov, Dmitriy Blokhin, Dieter Müller, Vladimir Klochkov, and Olga Ilinskaya Copyright © 2016 Yulia Sokurenko et al. All rights reserved.