On the Convergence of Bernstein-Stancu Polynomials in the Variation Seminorm

This article studies the variation detracting property and rate of approximation of the Bernstein-Stancu polynomials in the space of functions of bounded variation with respect to the variation seminorm. Moreover, we will present Voronovskaya-type theorems for Bernstein-Stancu polynomials B_{n, α, β}f and for the first derivative of these polynomials. Finally we include some graphical examples.     

Phytochemical screening and biological activities of Eminium spiculatum (Blume) Kuntze (family Araceae)

Eminium spiculatum (Blume) Kuntze (Araceae) is an indigenous plant in Jordan used as an anticancer agent. The objective of this study was to determine the chemical composition of E. spiculatum and its antimicrobial, antiplatelet and antiproliferative activities. After isolation, antimicrobial activity was tested using well-in-agar method and in vitro platelet aggregation by aggrometric method. Antiproliferative activity was evaluated by Sulphorhodamine B assay. Luteolin, luteolin-7-O-glucoside, isoorientin, vitexin, chrysoeriol-7-O-glucoside and β-sitosterol were isolated and their structures determined. Luteolin exhibited moderate antibacterial activity against Escherichia coli and resistant strains of Staphylococcus aureus in 1 μg mL(-1) concentration. Luteolin, luteolin-7-O-glucoside and vitexin inhibited ADP and collagen-induced platelet aggregation in a concentration-dependent manner. For the determination of the antiproliferative activity, MCF-7 and T47D were used. Luteolin demonstrated the highest inhibitory activity with IC(50) values of 14.92 and 18.49 μmol L(-1) for MCF-7 and T47D, respectively. This research provided evidence about the chemical composition and biological activity of E. spiculatum.     

Synthesis and anticancer activity of some new pyridine derivatives

Different substituents were introduced in positions 2 and 6 of 2,6 diaminopyridine in order to obtain new heterocyclic compounds. A new series of aza pyridine, imidazopyridine, benzodiazepine, indole, pyrimidine, and benzimidazole heterocyclic derivatives were synthesized in good yields. The anticancer activities of some of the new compounds were evaluated against liver cancer cell line HEPG2. Compounds 3, 4, 10, 11, 12, and 17 showed the highest activity when compared to 5-flurouracil (5-FU) and doxorubicin (DOX) chemotherapy.     

A comparative study of complexation of enalapril with α-, β- and γ-cyclodextrins in aqueous medium: structure elucidation of inclusion complexes using NMR spectroscopic and molecular mechanics methods

Structural studies of complexes of enalapril maleate with α-, β- and γ-cyclodextrins were carried by NMR spectroscopy and computational methods. The formation of complexes of enalapril with all the three cyclodextrins was established by chemical shift changes observed in the cavity protons of cyclodextrins in the presence of enalapril maleate. The stoichiometry of the complexes was determined to be 1:1 by ¹H NMR titrations studies using Scott’s method. Intermolecular cross peaks observed in the 2D ROESY spectra of mixtures of enalapril maleate with three cyclodextrins helped in establishing the probable structures of these inclusion complexes which were supported by molecular mechanics (MM2) studies. Enalapril forms 1:1 inclusion complex with all the studied cyclodextrins through aromatic ring. The mode of approach of aromatic ring to the α-cyclodextrin cavity was found to be different from those of β- and γ-cyclodextrins, which were identical.     

Electrochemical and Theoretical Investigations of the Role of the Appended Base on the Reduction of Protons by [Fe2(CO)4(κ2‐PNPR)(μ‐S(CH2)3S] (PNPR={Ph2PCH2}2NR,R=Me,Ph)

The behavior of [Fe₂(CO)₄(κ²‐PNP^R)(μ‐pdt)] (PNP^R=(Ph₂PCH₂)₂NR, R=Me ( 1 ), Ph ( 2 ); pdt=S(CH₂)₃S) in the presence of acids is investigated experimentally and theoretically (using density functional theory) in order to determine the mechanisms of the proton reduction steps supported by these complexes, and to assess the role of the PNP^R appended base in these processes for different redox states of the metal centers. The nature of the R substituent of the nitrogen base does not substantially affect the course of the protonation of the neutral complex by CF₃SO₃H or CH₃SO₃H; the cation with a bridging hydride ligand, 1 μH⁺ (R=Me) or 2 μH⁺ (R=Ph) is obtained rapidly. Only 1 μH⁺ can be protonated at the nitrogen atom of the PNP chelate by HBF₄?Et₂O or CF₃SO₃H, which results in a positive shift of the proton reduction by approximately 0.15 V. The theoretical study demonstrates that in this process, dihydrogen can be released from a η²‐H₂ species in the Fe^IFe^II state. When R=Ph, the bridging hydride cation 2 μH⁺ cannot be protonated at the amine function by HBF₄?Et₂O or CF₃SO₃H, and protonation at the N atom of the one‐electron reduced analogue is also less favored than that of a S atom of the partially de‐coordinated dithiolate bridge. In this situation, proton reduction occurs at the potential of the bridging hydride cation, 2 μH⁺ . The rate constants of the overall proton reduction processes are small for both complexes 1 and 2 (k_obs≈4–7 s^?1) because of the slow intramolecular proton migration and H₂ release steps identified by the theoretical study.     

{Mo2O2S2}2+-directed synthesis of a polyoxotungstoarsenate(III). Structure and 183W NMR studies of the [(α–AsW9O33)3(WO(OH2))3(Mo2O2S2(H2O)4)]13− anion

Reaction of the [Mo₂O₂S₂(OH₂)₆]²⁺ aqua cation and [WO₄]^2? with the trivacant ion [α-B-AsW₉O₃₃]^9? in acidic condition (pH = 1.4) leads to the formation of a {Mo₂S₂O₂}-supported polyoxotungstate. The mixed salt NMe₄K₁₂[(α–AsW₉O₃₃)₃(WO(OH₂))₃(Mo₂O₂S₂(H₂O)₄)]?20H₂O (noted TMAK₁₂–1) has been obtained as single crystals and structurally characterized by X-ray diffraction analysis. The structural analysis of TMAK₁₂-1 reveals a molecular polyoxotungsto-arsenate (III) framework consisting of three α-{AsW₉O₃₃} subunits mutually linked by three {O = W-OH₂}⁴⁺ groups. The resulting triangular arrangement delimits a large “open-space”, lined on the periphery by six terminal oxygen atoms. The central cavity is partially filled by a single {Mo₂O₂S₂(OH₂)₄}²⁺ which spans two {AsW₉O₃₃} subunits. Furthermore, three potassium ions have been located, one being embedded within the central cavity and the other two, symmetrically distributed at the periphery of the central cavity. In the solid state, two anions 1 interact through hydrogen bonds and ionic contacts to give a large dimeric arrangement bordered by two TMA⁺ cations. 1 has been characterized in solution (Li⁺ salt) by its ¹⁸³W NMR spectrum which contains 16 lines in agreement with the C_s idealized symmetry assumed for the isolated anion 1. Infrared data and elemental analysis are also supplied.     

Biosynthesis of Au nanoparticles using olive leaf extract: 1st Nano Updates

The biological synthesis of gold nanoparticles (AuNPs) of various shapes (triangle, hexagonal, and spherical) using hot water olive leaf extracts as reducing agent is reported. The size and the shape of Au nanoparticles are modulated by varying the ratio of metal salt and extract in the reaction medium. Only 20 min were required for the conversion into gold nanoparticles at room temperature, suggesting a reaction rate higher or comparable to those of nanoparticles synthesis by chemical methods. The variation of the pH of the reaction medium gives AuNPs nanoparticles of different shapes. The nanoparticles obtained are characterized by UV–Vis spectroscopy, photoluminescence, transmission electron microscopy (TEM), X-ray diffraction (XRD), FTIR spectroscopy and thermogravimetric analysis. The TEM images showed that a mixture of shapes (triangular, hexagonal and spherical) structures was formed at lower leaf broth concentration and high pH, while smaller spherical shapes were obtained at higher leaf broth concentration and low pH.     

Synthesis,Spectral Properties and Structure of New Novel 3,3′-Dibenzoyl-1,1′-(propan-1,3-diyl)-bisthiourea

Abstract  

A new 3,3′-dibenzoyl-1,1′-propan-1,3-diyl)bisthiourea was synthesized by using benzoylisothiocyanate with 1,3-diaminopropane in aprotic solvent. The structure was determinated by means of FT-IR, ¹H-NMR, ¹³C-NMR and mass spectroscopic techniques. The crystal structure of 3,3′-dibenzoyl-1,1′-(propan-1,3-diyl)bisthiourea has also been examined by using X-ray crystallographic techniques and found to be crystallized in the monoclinic space group P2 ₁ /c with the unit cell parameters: a = 5.968(1) ?, b = 19.471(2) ?, c = 16.585(2) ?, β = 98.32(1)°, V = 1907.0(4) ?³, Dx = 1.395 g cm⁻³, and Z = 4 respectively.     

Labeling of acetaminophen with I-131 and biodistribution in rats

The aim of the present study was to label acetaminophen (APAP) with I-131 and to determine its radiopharmaceutical potential in rats. Acetaminophen was labeled with I-131 using the iodogen method. The radiochemical purity of (131)I-APAP was determined by RTLC and paper electrophoresis. The labeling yield was 94 +/- 4%. The biodistribution studies of the labeled compound (specific activity; 56.60 GBq/mmol) were performed in male Albino Wistar rats. The uptake of (131)I-APAP in some organs were determined at different time after injection to the rats. The radioactivity in each organ was counted and the percentage of injected activity per gram of tissue weight (%ID/g) for each organ and blood was calculated. (131)I-APAP uptake in the lung, liver, kidneys, pancreas, blood, stomach and some brain region, were observed. Thus, (131)I-APAP may be radiopharmaceutical for the imaging of the brain.     

Fluorescent aminoarylcyclotetraphosphazenes

In the present work, octachlorocyclotetraphosphazatetraene (1), N₄P₄Cl₈, is reacted with aniline (2), 1-napthylamine (4) and 2-aminoanthracene (6) to give octakis(arylamino)cyclotetraphosphazenes (3, 5 and 7). These cyclotetraphosphazene compounds (3, 5 and 7) have been fully characterized by elemental analysis, mass (MS), FT-IR, ¹H and ³¹P NMR spectroscopies. The molecular and crystal structures of 5 have been characterized by X-ray crystallography. The structure of 5 is monoclinic with the space group P21/c. The octakis(1-napthylamino)-(5) and octakis(2-aminoanthracene)-(7) cyclotetraphosphazene compounds have been synthesised for the first time in this study. The fluorescence properties of 3, 5 and 7 have been investigated in tetrahydrofuran (THF) and have been shown to have highly fluorescence behavior. This work also presents the quenching of arylamino substituted cyclotetraphosphazene derivatives (3, 5 and 7) by p-benzoquinone (BQ) or hydroquinone (HQ).