Powder Diffraction Spectra Research Articles

The protective effect of nitronyl nitroxide radical on peroxidation of A549 cell damaged by iron overload.

Particulate pollution in the air has strong links with increased morbidity of cardiopulmonary diseases. Iron is one of the major carcinogens in air pollution and can produce hydroxyl radical which induce oxidative stress, lead to cell damage and even to cancer. In this work, a novel nitronyl nitroxide radical NITPh(OMe)2 (2-(2,4-dimethoxyphenyl) -4,4,5,5- tetramethylimidazoline- 1- oxyl-3- oxide) was prepared and characterized by electron spin-resonance spectroscopy (ESR), X-ray crystal diffraction, Fourier transform infrared (IR), X-ray powder diffraction (XRD), elemental analysis, ultraviolet and visible spectra (UV-Vis), and the electronic transition processes was also calculated by time-dependent density functional theory (TDDFT) to analysis UV-Vis spectrum. In vitro cell model of oxidative damage was established by ferric ammonium citrate (FAC) overload, and NITPh(OMe)2 was studied as a free radical scavenger to protect peroxidation of A549 cells. Results showed that NITPh(OMe)2 could significantly alleviate the damage of A549 cells by iron overload in cell morphology, cell viability, cell proliferation and cell apoptosis. The apoptotic signaling pathway of A549 cells induced by FAC and the protection mechanism of NITPh(OMe)2 were all discussed through the expression of three relating proteins, Bcl-2, Bax and DDIT3. This work confirms that nitroxide radicals are effective antioxidants, and have potential application in clinical practice as therapeutic agents.

Defect structure and holographic storage properties of LiNbO3:Zr:Fe:Cu crystals with various Li/Nb ratios

A series of LiNbO3:Zr:Fe:Cu single crystals with various Li/Nb ratios ranging from 0.946 to 1.38 were grown in air by the Czochralski method. Both X-ray powder diffraction and ultraviolet absorption spectra have been examined, and are discussed with regard to the defect structure of the as-grown crystals. In addition, the conventional two-wave coupling experiment has been conducted with 532 nm laser to reveal the holographic storage properties. The results have shown the macroscopic photorefractive properties to correspond well to the microscopic defect structure changing with the composition. More specifically, LiNbO3:Zr:Fe:Cu crystals possess at once relatively high sensitivity, fast response time and dynamic range comparable with that of LiNbO3:Zr:Fe crystals, and at the same time maintain high saturation diffraction efficiency (up to 68%) close to that of typical photorefractive LiNbO3:Fe crystals (70%), as such denoting their potential as prominent holographic storage media.

Synthesis and Characterization of Magnetic Rubidium Superoxide, RbO<sub>2</sub>

Polycrystalline rubidium superoxide (RbO2) has been synthesized by using solution method followed by the reaction process under the cooling condition of-40 °C. X-ray Powder Diffraction (XRD) spectra showed that RbO2 was successfully synthesized by this method. The magnetic susceptibility and pulsed muon spin relaxation (μSR) measurements were carried out in order to study the magnetic properties of RbO2.

Spectroscopic characterization and XRD of some new metal complexes with dithranol in presence of 8-hydroxyquinoline

IN THE PRESENT work, dithranol (Dithr) reacts with Ni(II), Zn(II), Zr(IV), La(III), and Th(IV) in presence of heterocyclic ligand 8-hydroxyquinoline (8HQ) in acetone forming new mixed ligand complexes. The structures of the synthesized complexes were characterized by conventional techniques including melting point, molar conductivity, magnetic properties, elemental analyses, infrared, ultraviolet-visible, 1H nuclear magnetic resonance, and X-ray powder diffraction (XRD) spectra, as well as thermogravimetric (TG) and differential thermogravimetric (DTG) analyses. The molar conductance values of the metal complexes in dimethyl sulphoxide (DMSO) indicated that the complexes were found to be electrolytes with different ratios. The magnetic susceptibility measurements for Ni(II) complex is 3.1 BM with distorted octahedral geometry. TG/DTG studies confirmed the chemical formula for these complexes and established the thermal decomposition processes ended with the formation of metal oxide contaminated with carbon atom. The infrared spectra of the complexes showed shift for ν(O-H) and ν(C=N) in all complexes, which indicated the coordination of oxygen atom of phenolic group and nitrogen atom of pyridine ring of 8HQ with metal ions. X-ray powder diffraction analysis of the compounds showed that Dithr, 8HQ, and their metal complexes display crystalline peaks except Zr(IV) and La(III) complexes.

ZrS3: From crystalline samples to colloid dispersions

A series of ZrS3 samples have been synthesized from elements at temperatures from 350 to 650°C. Stable ZrS3 colloid dispersions in different organic media (acetonitrile, dimethylformamide, ethanol, and isopropanol) were obtained from the polycrystalline samples. The structural and spectroscopic identities of the ZrS3 particles were confirmed by X-ray powder diffraction and Raman spectra. The sizes and morphology of particles in the colloid dispersions have been studied by transmission electron microscopy and dynamic light scattering method; the concentrations of the dispersions were found to depend on condition of synthesis of the initial bulk ZrS3.

Temperature-dependent luminescence of BaLaMgNbO6:Mn4+, Dy3+ phosphor for dual-mode optical thermometry

We have co-doped Mn4+ and Dy3+ into a perovskite structure host BaLaMgNbO6 (BLMN) in order to develop a new scheme of dual-mode optical thermometry. All the samples including single-doped and co-doped samples were successfully synthesized via a high-temperature solid-state reaction method. The phase purity and luminescence properties of the phosphors were characterized by X-ray powder diffraction, photoluminescence excitation and emission spectra. In particular, temperature-dependent emission spectra as well as luminescence decay curves measurements were performed on the co-doped BLMN:Mn4+, Dy3+ sample to inspect its temperature-dependent luminescence properties. Under 355 nm excitation, the fluorescence intensity ratio (FIR) between Dy3+ emission at 580 nm (4F9/2 → 6H13/2) and Mn4+ emission at 698 nm (2Eg→4A2g) as well as the fluorescence lifetime of Mn4+ (2Eg→4A2g) were investigated in the temperature range from 230 K to 470 K, and the maximum relative sensitivities are 1.82% K−1 at 457 K and 2.43% K−1 at 437 K, respectively. It should be noted that the emission peak of Mn4+ whose luminescence can be employed by lifetime-mode temperature sensing is located in the optical window of biological tissue, which could be used in biological application. All these investigations suggest that the BLMN:Mn4+, Dy3+ phosphor is very promising in dual-mode high-sensitivity optical thermometry.

Coligand syntheses, crystal structures, luminescence and photocatalytic properties of 2D and 3D Ni(II) coordination polymers based on terephthalic acid and flexible bis(benzimidazole) linkers

Two new Ni(II) coordination polymers (CPs) [Ni(TP)(L1)(H2O)]n (1) and [Ni(TP)(L2)]n (2), were synthesized via hydrothermal reaction (H2TP = terephthalic acid, L1 = 1,6-bis(2-methylbenzimidazol-1-yl)hexane, L2 = 1,6-bis(5,6-dimethylbenzimidazol-1-yl)hexane, and structurally characterized by X-ray single crystal diffraction analysis, elemental analyses, thermogravimetric analysis, X-ray powder diffraction and IR spectra. CP 1 exhibits a 2D hcb layer, which is further extended into 3D supramolecular architecture by classical O–H⋯O hydrogen-bonding interactions. CP 2 possesses a 3D 4-connected sra framework. Both CPs possess high thermal stability and promising photocatalytic activities for the degradation of methylene blue (MB) under UV irradiation. The photocatalytic mechanism was investigated by introducing benzoquinone (BQ), the ammonium oxalate (AO), and tert-butyl alcohol (TBA) as superoxide radical (·O2−), hole (h+), and hydroxyl radical (·OH) scavengers, respectively.

Fluorescent UO2(II) and ZrO(II) complexes: Synthesis, structural characterization, fluorescence, DNA binding studies and biological applications in cell probing

A new series of UO2(II) and ZrO(II) azo‐complexes based on 5‐nitro‐8‐hydroxyquinoline; [UO2(H2L1)(NO3)EtOH] (1), [ZrO(H2L1)(NO3)H2O] (2), [UO2(HL2)(NO3)EtOH]3H2O (3), [ZrO(HL2)(NO3)EtOH] (4), [UO2(HL3)(NO3)(H2O)3]2H2O (5) and [ZrO(HL3)(NO3)EtOH] (6); have been synthesized. The structure of these complexes has been characterized using elemental analysis, thermal analysis, molar conductance, UV–vis, IR, electron impact mass, X‐ray powder diffraction and NMR spectra. The results revealed the formation of non‐electrolyte mononuclear complexes via the N atom of the azo group or of the quinoline ring and the oxygen atom of the deprotonated OH. Fluorescence properties of the synthesized complexes have been examined and the fluorescence quantum yield (Φf) has been determined. The complexes have been tested as cell staining and imaging under the fluorescent microscope. The data showed that complexes 1 and 2 efficiently stain the nuclei in addition to some focal cytoplasmic areas. Other than complexes 3 and 4 exclusively stained the nuclei. On the other hand, complexes 5 and 6 stained the cytoplasm exclusively. It has been demonstrated that complex 4 was the most effective in cell staining. The binding constant (Kb) with DNA was calculated using UV–vis absorption titration and fluorescence spectral methods. It was concluded that complex 4 can be used effectively as fluorescent probes in studying cell biology.

Structural, optical and electrochemical properties of TiO2 nanoparticles synthesized using medicinal plant leaf extract

Abstract The flower like TiO2 nanoparticles have been identified as potential electrode material for efficient next generation electrochemical energy storage devices. The present work reports, a novel green approach to synthesize high surface area TiO2 nanoparticles using medicinal plant leaf extracts namely Ocimum Tenuiflorum Plant and Calotropis Gigantea Plant. The TiO2 nanoparticles synthesized using Calotropis Gigantea plant confirmed rutile phase from X-ray powder diffraction and Raman spectra. The fourier transform infrared spectroscopy spectra of the sample indicate the presence of TiO2 vibrational bonds. The field emission scanning electron microscopy images revealed that the flower like shape of nano-granules with an average granule size of 200 nm. The presence of Ti and O elements qualitatively confirmed using energy dispersive spectroscopy spectra, which shows the good stoichiometry in the sample. The flower like shapes with nano petals were further disclosed with the help of high resolution transmission electron microscopy. The corresponding optical band gap was observed to be 3.0 eV. The electrochemical investigations of the sample exhibited a high specific capacitance of 224 F g-1 at 0.5 A g-1 with 71% of capacitive retention after 5000 cycles.

Liquid-Phase Epitaxial Growth and Characterization of Nd:YAl3(BO3)4 Optical Waveguides

We investigated the fabrication of neodymium doped thin film optical waveguide-based devices as potential active sources for planar integrated optics. Liquid-phase epitaxial growth was used to fabricate neodymium-doped yttrium aluminum borate films on compatible lattice-matched, un-doped yttrium aluminum borate substrates. We observed the refractive index contrast of the doped and un-doped crystal layers via differential interference contrast microscopy. In addition, characterization by X-ray powder diffraction, optical absorption and luminescence spectra demonstrated the crystal quality, uniformity and optical guiding of the resulting thin films.

Advanced Spectral Analysis Program.

Advanced Spectral Analysis Program is a LabVIEW-based program intended for rapid and accurate analysis of large sets of spectral data. It can handle a range of different types of data including angle-resolved and energy-dispersive powder diffraction and Raman spectra. We present it here with a focus on high-temperature high-pressure powder diffraction. The program contains a novel graphical user interface that allows rapid manual fitting and indexing of peaks which require precise fitting ranges and includes tools for fitting any Bravais lattice and arbitrary user-defined multivariate equations of state. The program allows the user to simultaneously view and manipulate multiple data sets from an experiment. The user can save and load analysis progress at any point, allowing for repeatable calculations to be performed, and to allow the fast comparison of different analysis parameters.

Synthesis, chemical and biological investigations of new Ru(III) and Se(IV) complexes containing 1,3,5-triazine chelating derivatives

A series of vital complexes of [Se (Ln) (Cl)x]·yCl (where n = L1, L2, L3 and L4; x = 1, 2, or 3 and y = 1, 2, or 3) and [Ru (Ln) (Cl)x (H2O)y]zCl (where x = 2 or 3; y = 0,1 or 2 and z = 0 or 1) have been synthesized from the chemical reactions between ruthenium (III) or selenium (IV) salts and tri-substituted s-triazine derivatives (L1 = N2-(4-chlorophenyl)-N4,N6-di (pyrimidin-2-yl)-1,3,5-triazine-2,4,6-triamine; L2 = N2-(4-chlorophenyl)-N4- (pyrimidin-2-yl)- N6- (thiazol-2-yl)-1,3,5-triazine-2,4,6-triamine; L3 = 6-chloro-N2-(pyrimidin-2-yl)-N4-(1H-1,2,4-triazol-3-yl)-1,3,5-triazine-2,4-diamine and L4 = 6-chloro-N2-(4-chlorophenyl)-N4-(pyrimidin-2-yl)-1,3,5-triazine-2,4-diamine). The structural was investigated using of elemental analyses, molar conductance, IR, UV–Vis, magnetic susceptibility, 1H, 13C NMR spectra and thermal analyses. The surface morphology behaviors of selenium (IV) and ruthenium (III) complexes were studied based on scanning and transmittance electron microscopes. The crystalline nature of s-triazine complexes have been investigated using X-ray powder diffraction spectra. Spectral results were concluded that the ligand acts as a neutral bidentate for (L1 and L4) and tridentate for (L2 and L3), and coordinates through the nitrogen atom of triazine ring and nitrogen atoms of (pyrimidine, thiazole, and triazole) rings towards metal ion. The cytotoxic IC50 results of the free Ln ligands and its selenium (IV) complexes in vitro against the human colon and lung cancer cell lines introduced a promising efficiency.

Structural and Optical Properties of Ce3+ Doped ZnS Nanoparticles

ZnS nanoparticles doped with various concentration of Cerium were synthesized by solid state reaction method. The presence of Ce3+ ions in the synthesized samples were verified using X-ray powder diffraction and energy-dispersive X-ray spectrum. XRD analysis showed that sample prepared were hexagonal zinc sulphide with particles’ size in the ranges 36 nm–45 nm. The crystallite size of the particles increases with Ce3+ doping. UV-Vis absorption spectroscopy measurements have shown that the strongest absorption peak of nano ZnS is blue shifted compared to bulk ZnS. The strongest absorption peak of Ce3+ doped nano ZnS is red shifted with respect to parent nano ZnS. The existence of functional groups was identified using Fourier transform infrared spectrometer. The PL emission studies of Ce3+ doped ZnS revealed good emission at 422 nm and 459 nm when excited with wavelength 290 nm.

Synthesis of Sulfur-Resistant TiO2-CeO2 Composite and Its Catalytic Performance in the Oxidation of a Soluble Organic Fraction from Diesel Exhaust

Sulfur poisoning is one of the most important factors deteriorating the purification efficiency of diesel exhaust after-treatment system, thus improving the sulfur resistibility of catalysts is imperative. Herein, ceria oxygen storage material was introduced into a sulfur-resistant titania by a co-precipitation method, and the sulfur resistibility and catalytic activity of prepared TiO2-CeO2 composite in the oxidation of diesel soluble organic fraction (SOF) were studied. Catalytic performance testing results show that the CeO2 modification significantly improves the catalytic SOF purification efficiency of TiO2-CeO2 catalyst. SO2 uptake and energy-dispersive X-ray (EDX) results suggest that the ceria doping does not debase the excellent sulfur resistibility of bare TiO2, the prepared TiO2-CeO2 catalyst exhibits obviously better sulfur resistibility than the CeO2 and commercial CeO2-ZrO2-Al2O3. X-ray powder diffraction (XRD) and Raman spectra indicate that cerium ions can enter into the TiO2 lattice and not form complete CeO2 crystals. X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR) and oxygen storage capacity (OSC) testing results imply that the addition of CeO2 in TiO2-CeO2 catalyst can significantly enhance the surface oxygen concentration and oxygen storage capacity of TiO2-CeO2.

Application of Ball Milling for Highly Selective Mechanochemical Polymorph Transformations

Milling is an important secondary processing technique in the manufacture of pharmaceuticals, primarily used as a particle size reduction process. p-Aminobenzoic acid (PABA), m-aminobenzoic acid (MABA), o-aminobenzoic acid (OABA), and carbamazepine (CBZ) are pharmaceutically relevant compounds that can exist in different polymorphic forms with distinct packing motifs and thus different physicochemical properties. A comprehensive study of the effect of milling on the polymorphism of PABA, MABA, OABA, and CBZ was carried out. Milling of PABA in the presence of catalytic amounts of valeric acid or methanol yielded the β polymorph, which is otherwise difficult to obtain in bulk quantities. Milling also proved to be a more convenient method for producing MABA form IV compared with previously reported procedures. Principal component analysis of the pair distribution function-transformed X-ray powder diffraction spectra of ball-milled CBZ samples showed that the milling-induced polymorphic transformation strongl...

Preparation and In Vitro Evaluation of Ibuprofen Spherical Agglomerates.

Ibuprofen, an anti-inflammatory drug, is characterized by poor water solubility, which limits its pharmacologic effects. The present work aimed to the study the effect of agglomeration on the micromeritic properties and dissolution of ibuprofen. Ibuprofen agglomerates were prepared by solvent change method using water, dichloromethane and DMSO as poor solvent, bridging liquid and good solvent respectively in the ratio of 57.5:12.5:30. Process variables such as amount of bridging liquid, mode of addition, temperature and stirring rate were optimized. SEM studies indicate that agglomerates produced were spherical and exhibit irregular shape. X-Ray Powder Diffraction spectra revealed the absence of polymorphism. DSC spectra showed no change in melting point indicating absence of crystal modification. The agglomerates exhibited improved solubility, dissolution rate and micromeritic properties compared to pure drug. Anti-inflammatory studies were conducted in Wistar strain male albino rats and ibuprofen agglomerates showed more significant activity than the pure drug which may be due to better absorption. Ulcerogenic potential study was carried out for pure ibuprofen and agglomerates. Better ulcerogenic potential was observed in ibuprofen agglomerates treated rats.

Chlamydomonas angulosa (Green Alga) and Nostoc commune (Blue-Green Alga) Microalgae-Cellulose Composite Aerogel Beads: Manufacture, Physicochemical Characterization, and Cd (II) Adsorption.

This study presents composite aerogel beads prepared by mixing dissolved cellulose with Chlamydomonas angulosa and Nostoc commune cells, respectively, at 0.1, 0.3, and 0.5% (w/w). The manufactured composites (termed regenerated cellulose (RC)), with C. angulosa (RCCA-(1, 3, and 5)), and with N. commune (RCNC-(1, 3, and 5)) were analyzed. Both RCCA-5 and RCNC-5 showed the high specific surface area to be about 261.3 and 332.8 m2·g−1. In the microstructure analysis, network structures were observed in the cross-sections of RC, RCCA-5, and RCNC-5. The pyrolysis temperature of the RCCA-5 and RCNC-5 composite aerogel beads was rapidly increased about 250 °C during the mixing of cellulose with C. angulosa and N. commune. The chemical analysis of RC, RCCA-5, and RCNC-5 showed peaks corresponding to various functional groups, such as amide, carboxyl, and hydroxyl groups from protein, lipid, and carbohydrate. RCNC-5 at pH 6 demonstrated highest Cd2+ removal rate about 90.3%, 82.1%, and 63.1% at 10, 25, and 50 ppm Cd2+, respectively. At pH 6, Cd2+ adsorption rates per unit weight of the RCNC-5 were about 0.9025, 2.0514, and 3.1547 mg/g at 10, 25, and 50 ppm, respectively. The peaks assigned to the amide, carboxyl, and hydroxyl groups in RCCA-5, RCNC-5, and RC were shifted or disappeared immediately after adsorption of Cd2+. The specific surface area, total pore volume, and mean pore diameter of composites was decreased due to adsorption of Cd2+ on the developed materials. As can be seen in the X-ray powder diffraction (XRD) spectrum, significant changes in the molecular structure of the composite aerogel beads were not observed even after adsorption of Cd2+.

A novel white-light-emission phosphor Dy3+-doped CaLaB7O13 under UV excitation

White-light-emitting phosphors Dy3+-doped CaLaB7O13 were synthesized by solid-state reaction, and their luminescent properties were characterized for the applications in white-light-diodes (W-LEDs). The obtained samples were initially investigated by X-ray powder diffraction, photoluminescence excitation and emission spectra, the Commission International de L’Eclairage (CIE) chromaticity coordinates, and thermally stable properties. Dy3+-doped CaLaB7O13 phosphors emitted a blue emission band centered at 480 nm and a yellow one centered at 575 nm with CIE chromaticity coordinates of (0.325, 0.339) under the excitation of near-UV (NUV) LED chips at 365 nm. The electric dipole-dipole interaction was demonstrated to be the energy transfer mechanism in Dy3+-doped CaLaB7O13 phosphors, and the critical distance of energy transfer between the Dy3+ ions was estimated to be about 0.920 nm. The temperature-dependent spectra imply Dy3+-doped CaLaB7O13 show small thermal quenching. The present work indicated that Dy3+-doped CaLaB7O13 was a promising white-light-emitting phosphor excited by NUV LED.

Enhanced Low Temperature NO Reduction Performance via MnOx-Fe2O3/Vermiculite Monolithic Honeycomb Catalysts

Selective catalytic reduction of NOx by ammonia (NH3-SCR) was the most efficient and economic technology for De-NOx applications. Therefore, a series of MnOx/vermiculite (VMT) and MnOx-Fe2O3/VMT catalysts were prepared by an impregnation method for the selective catalytic reduction (SCR) of nitrogen oxides (NOx). The MnOx-Fe2O3/VMT catalysts provided an excellent NO conversion of 96.5% at 200 °C with a gas hourly space velocity (GHSV) of 30,000 h−1 and an NO concentration of 500 ppm. X-ray photoelectron spectroscopy results indicated that the Mn and Fe oxides of the MnOx-Fe2O3/VMT catalyst were mainly composed of MnO2 and Fe2O3. However, the MnO2 and Fe2O3 components were well dispersed because no discernible MnO2 and Fe2O3 phases were observed in X-ray powder diffraction spectra. Corresponding MnOx-Fe2O3/VMT monolithic honeycomb catalysts (MHCs) were prepared by an extrusion method, and the MHCs achieved excellent SCR activity at low temperature, with an NO conversion greater than 98.6% at 150 °C and a GHSV of 4000 h−1. In particular, the MnOx-Fe2O3/VMT MHCs provided a good SCR activity at room temperature (20 °C), with an NO conversion of 62.2% (GHSV = 1000 h−1). In addition, the NO reduction performance of the MnOx-Fe2O3/VMT MHCs also demonstrated an excellent SO2 resistance.

Enhancement of red emission intensity of Ca2Al2SiO7:Eu3+ phosphor by MoO3 doping or excess SiO2 addition for application to white LEDs

Ca1.86Al2(Si1-xMox)O7:0.14Eu3+ and Ca1.86Al2Si1+yO7+2y:0.14 Eu3+ were synthesized by solid-state reaction. X-ray powder diffraction, excitation and emission spectra were used to investigate their structures and photoluminescence properties. The results shows that the phosphor Ca1.86Al2SiO7:0.14Eu3+ cannot be excited efficiently by light of 393 nm. The introduced Mo ion does not change the position of the excitation peak, but increases both the absorption at 400nm and the emission intensity of Eu3+. The intense red emitting phosphor Ca1.86Al2(Si0.95Mo0.05)O7:0.14Eu3+ was obtained, which has 67% enhanced luminous intensity compared to that of the undoped sample Ca1.86Al2SiO7:0.14Eu3+. Otherwise, SiO2 excess of non-stoichiometric phosphors Ca1.86Al2Si1+yO7+2y:0.14Eu3+ showed the characteristic pattern of a tetragonal structure with a small SiO2 concentration. The optimal phosphor of Ca1.86Al2Si1.1O7.2:0.14Eu3+ has a luminous intensity about two times higher than that of the original stoichiometric phosphor Ca1.86Al2SiO7:0.14Eu3+. We confirmed that the photoluminescence intensity of the obtained phosphors is fairly enhanced by excessive SiO2. The mechanism of this photoluminescence enhancement is discussed in this paper.