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The crystallinity and the photoluminescent properties of spray pyrolized ZnO phosphor containing Eu and Eu ions

A europium doped ZnO (ZnO:Eu) particle was directly synthesized by the spray pyrolysis method. The crystal structure of samples was designated by the europium ion and the synthesis temperature. We identified the coexistence of Eu²⁺ and Eu³⁺ ions in the as prepared ZnO, which was strongly influenced by the doping concentration and the synthesis temperature. With addition of a 0.5 mol% concentration of europium ions, only the Eu²⁺ ion existed in particles, while both Eu²⁺ and Eu³⁺ ions existed in sample using 1 mol% or higher concentration of europium ions. Changing the wavelength of the excitation source, we also found that both the blue and red luminescence can be obtained.     

Synthesis of Single Crystalline ZnO Nanoparticles by Salt-Assisted Spray Pyrolysis

LiNO₃ was used as a shield in the preparation of single crystalline ZnO particles by a spray pyrolysis process in order to prevent agglomeration and enhance the crystallinity of the ZnO. LiNO₃ was added to a precursor solution of zinc acetate dihydrate prior to its atomization by means of an ultrasonic transducer. Agglomerate-free particles having a mean particle size of 26 nm were successfully obtained after washing the product. X-ray diffractometry, field-emission scanning electron micrograph and transmission electron micrograph data indicate that the size and morphology of ZnO were strongly influenced by the operating temperature used and the residence time of the particle in the reactor.     

The crystal and molecular structure of trans-tetracarbonylbis(triphenyl-phosphine)chromium(0) in a new unit cell: Is the trans conformer more stable than the cis?

The crystal and molecular structure of trans-Cr(CO)₄(PPh₃)₂ has been determined by single crystal X-ray diffraction. The structure differs from one previously reported, packing in a different unit cell with no molecular center of symmetry. This asymmetry, coupled with the noncoplanarity of the four equatorial carbonyl ligands indicates that the structure is dominated by steric interactions. In spite of this, density functional calculations oncis-M(CO)₄(PPh₃)₂ vs. trans-M(CO)₄(PPh₃)₂, M = Cr, Mo, and W, predict that the gas phase cis conformer is more stable than the trans conformer for all three metals. The complex crystallizes in the triclinic space group with lattice parameters a = 10.139(5) Å, b = 10.583(5) Å, c =17.911(5) Å, = 75.860(5)°, = 77.410(5)°, = 65.930(5)°, V =1686.3(12) ų, Z =2.     

X-ray Structure of <Emphasis Type="Italic">mer</Emphasis>-[Mo(CO)<Subscript>3</Subscript>(PPh<Subscript>3</Subscript>)(<Emphasis Type="Italic">κ</Emphasis><Superscript>2</Superscript>-dppm)]

Abstract  

Treatment of [Mo(CO)₃(NCMe)₃] with bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh₃) at 50 °C afforded mer-[Mo(CO)₃(PPh₃)(κ ²-dppm)] (1) in 55% yield which has been characterized by single crystal X-ray diffraction studies and spectroscopic measurements. Compound 1 crystallizes in the triclinic space group P−1 with a = 10.3449(6), b = 11.1570(6), c = 17.8961(10) ?, β = 80.8400(10)°, Z = 2 and V = 1959.8(2) ?³.     

Developing a miniaturized setup for in‐tube simultaneous determination of three alkaloids using electromembrane extraction in combination with ultraviolet spectrophotometry

Herein, electromembrane extraction was combined with ultraviolet spectrophotometry using a customized manifold for preconcentration and simultaneous determination of morphine, codeine, and papaverine in water and human urine samples. Absorption spectra of the extracts were recorded inside the lumen of the hollow fiber using two fiber optics connected to a miniature spectrophotometer. Partial least squares regression was applied to resolve the overlapped spectra of the analytes. Performance of the model was validated by an independent test set. Central composite design was applied to optimize the extraction parameters. The optimized extraction conditions are as follows; supporting liquid membrane: 2‐nitrophenyl octyl ether containing 15% v/v bis(2‐ethylhexyl) phosphate, applied voltage: 80 V, donor pH: 3.0, acceptor pH: 1.0, extraction time: 20 min. Finally, the optimized extraction method was validated for determination of the mentioned alkaloids in human urine samples. The method showed good linearity (R² > 0.995) for all of the mentioned alkaloids. The limits of detection for morphine, codeine, and papaverine in diluted human urine were found to be 0.6, 1.1, and 0.6 ng/mL, respectively with acceptable relative standard deviations. Enrichment factors of 104, 108, and 102 were achieved for morphine, codeine, and papaverine, respectively.     

Enhancing endothelial differentiation of human mesenchymal stem cells by culture on a nanofibrous polycaprolactone/(poly-glycerol sebacate)/gelatin scaffold

Cardiovascular diseases have always been one of the main causes of death worldwide and eventually one of the major medical concerns. Tissue engineering is promising strategies of treating cardiovascular, which can be an effective approach with the design of appropriate scaffold. In this study, to develop engineering basement membrane for endothelial differentiation with good cell attachment, we produced polycaprolactone (PCL)/poly (glycerol sebacate) (PGS)/gelatin nanofibrous scaffold via electrospinning. Attenuated total reflectance-Fourier transform infrared and the proton nuclear magnetic resonance results confirmed the chemical structure of synthesized PGS. Scanning electron microscope images of the electrospun scaffold revealed that the nanofibers are smooth, continues and uniform. Moreover, due to the presence of hydrophilic functional groups in the scaffold, the contact angle is in the appropriate range for cell adhesion especially endothelial cells. The elastic modulus and ultimate tensile stress of electrospun scaffold were calculated 1.32 ± 0.27 MPa and 1.23 ± 0.18 MPa respectively. Quantitative polymerase chain reaction was performed for evaluation of endothelial differentiation of mesenchymal stem cells cultured on standard plate and fibrous scaffold under chemical stimulation with growth factor. Specific endothelial gene expression results postulated that our modified scaffold could support and significantly promote endothelial differentiation of MSCs.