COMPARISON OF INTRAMUSCULAR VERSUS INTRAVENOUS KETAMINE FOR SEDATION IN CHILDREN UNDERGOING MAGNETIC RESONANCE IMAGING EXAMINATION.

OBJECTIVE: The aim: To compare efficacy of intramuscular (IM) versus intravenous (IV) ketamine for sedation in children undergoing brain MRI scanning in children. PATIENTS AND METHODS: Materials and methods: Children who required elective brain MRI were selected for this study. They were randomly divided into two groups; group I received 1.5 mg/kg IV Ketamine and group II received 4 mg/kg IM ketamine. In each group supplementary 0.1 mg/kg midazolam intravenously before positioning on MRI table was given. Patients were monitored for pulse rate, SPO2, and respiratory wave. RESULTS: Results: Children who received IM ketamine had significantly shorter scan time and a greater success rate of sedation with first dose than the IV group. The proportions of scan interruption and scan repeat were significantly higher among the IV group than in the IM group. The scan time was longer among the IV group than in the IM group with significantly more scan interruption and repeat. Satisfaction with sedation as expressed by the technicians was significantly more in the IM group than in IV group (98.1% vs. 80.8%, P= 0.004). CONCLUSION: Conclusions: Intramuscular ketamine injection was predicted to have a better sedative success rate and takes less time to complete than intravenous admin¬istration. This makes IM ketamine more appealing in certain conditions.

GGA and GGA + U Study of ThMn2Si2 and ThMn2Ge2 Compounds in a Body-Centered Tetragonal Ferromagnetic Phase.

Our study used the full-potential linearized augmented plane waves (FP-LAPW) method to conduct a first-principles evaluation of the structural, electronic, and magnetic properties of ThMn2X2 (X = Si and Ge) compounds. To establish theoretical dependability with the currently available experimental results, computations for the structural findings of ternary intermetallic thorium (Th)-based compounds were achieved using the generalized gradient approximation in the scheme of Perdew-Burke-Ernzerhof (PBE-GGA) potential, while the generalized gradient approximation plus the Hubbard U (GGA + U) approach was employed to improve the electrical and magnetic properties. In contrast with both the paramagnetic (PM) and antiferromagnetic (AFM) phases, the ThMn2X2 compounds were optimized in a stable ferromagnetic (FM) phase, which was more suited for studying and analyzing magnetic properties. The electronic band structures (BS) and the density of state (DOS) were computed using the two PBE-GGA and GGA + U approximations. The thorium (Th)-based ThMn2X2 compound has full metallic character, due to the crossing and overlapping of bands across the Fermi level of energy, as well as the absence of a gap through both spin (up and down) channels. There was a significant hybridization between (Mn-d and (X = Si and Ge)-p states of conduction band with Th-f states in the valence band. The total magnetic moment of ThMn2Si2 in the ferromagnetic phase was 7.94534 µB, while for ThMn2Ge2 it was 8.73824 µB with a major contribution from the Mn atom. In addition, the ThMn2Ge2 compound's total magnetic moment confirmed that it exhibits higher ferromagnetism than does the ThMn2Si2 compound.

Spin-Dependent First-Principles Study on Optoelectronic Properties of Neodymium Zirconates Pyrochlores Nd2Zr2O7 in Fd-3m and Pmma Phases.

Rare-earth zirconate pyrochlores (RE2Zr2O7) are of much fundamental and technological interest as optoelectronic, scintillator and thermal barrier coating materials. For the first time, we report the detailed optoelectronic properties of rare-earth zirconates Nd2Zr2O7 in both, i.e., for spin up and spin down states, via the use of first-principles density functional theory (DFT) procedure. To obtain the desired optoelectronic properties, we used a highly accurate method called full-potential linearized augmented plane wave (FPLAPW) within the generalized gradient approximation (GGA), parametrized with Hubbard potential U as an exchange-correlation function. The band gaps predicted for Nd2Zr2O7 were of the order 2.4 eV and 2.5 eV in Fd-3m and Pmma symmetrical phases, respectively. For both the phases, our research involved a complete examination of the optical properties of Nd2Zr2O7, including extinction coefficient, absorption coefficient, energy loss, function, reflectivity, refractive index, and real optical conductivity, analyzed in the spectral range from 0.0 eV to 14 eV. The calculated optical properties in both phases showed a considerable spin-dependent effect. The electronic bonding characteristics of different species in Nd2Zr2O7 within the two crystal symmetries were explored via the density distribution mapping of charge.

Cell viability and electrical response of breast cancer cell treated in aqueous graphene oxide solution deposition on interdigitated electrode.

Breast cancer is one of the most reported cancers that can lead to death. Despite the advances in diagnosis and treatment procedures, the possibility of cancer recurrences is still high in many cases. With that in consideration, researchers from all over the world are showing interest in the unique features of Graphene oxide (GO), such as its excellent and versatile physicochemical properties, to explore further its potential and benefits towards breast cancer cell treatment. In this study, the cell viability and electrical response of GO, in terms of resistivity and impedance towards the breast cancer cells (MCF7) and normal breast cells (MCF10a), were investigated by varying the pH and concentration of GO. Firstly, the numbers of MCF7 and MCF10a were measured after being treated with GO for 24 and 48 h. Next, the electrical responses of these cells were evaluated by using interdigitated gold electrodes (IDEs) that are connected to an LCR meter. Based on the results obtained, as the pH of GO increased from pH 5 to pH 7, the number of viable MCF7 cells decreased while the number of viable MCF10a slightly increased after the incubation period of 48 h. Similarly, the MCF7 also experienced higher cytotoxicity effects when treated with GO concentrations of more than 25 µg/mL. The findings from the electrical characterization of the cells observed that the number of viable cells has corresponded to the impedance of the cells. The electrical impedance of MCF7 decreased as the number of highly insulating viable cell membranes decreased. But in contrast, the electrical impedance of MCF10a increased as the number of highly insulating viable cell membranes increased. Hence, it can be deduced that the GO with higher pH and concentration influence the MCF7 cancer cell line and MCF10a normal breast cell.

Co2YZ (Y= Cr, Nb, Ta, V and Z= Al, Ga) Heusler alloys under the effect of pressure and strain.

Full Heuslers alloys are a fascinating class of materials leading to many technological applications. These have been studied widely under ambient conditions. However, less attention been paid to study them under the effect of compression and strain. Here in this work Co2YZ (Y= Cr, Nb, Ta, V and Z = Al, Ga) Heusler alloys have been studied comprehensively under pressure variations. Calculated lattice constants are in reasonable agreement with the available data. It is determined that lattice constant deceases with the increase in tensile stress and increases by increasing pressure in reverse direction. Band profiles reveals the half metallic nature of the studied compounds. The bond length decreases while band gap increases in compressive strain. The compounds are found to be reflective in visible region, as characteristics of the metals. The magnetic moments reveal the half-mettalic ferromagnetic nature of the compounds.

Synthesis, Crystal Structure, and Optical Gap of Two-Dimensional Halide Solid Solutions CsPb2(Cl1- xBr x)5.

Exploring new perovskite-related solid-state materials and the investigating composition-dependent structural and physical properties are highly important for advanced functional material development. Herein, we present the successful hydrothermal synthesis of tetragonal CsPb2Cl5 and the anion-exchange phase formation of CsPb2(Cl1- xBr x)5 ( x = 0-1) solid solutions. The CsPb2(Cl1- xBr x)5 crystal structures, which crystallize in the tetragonal system, space group I4/ mcm, with parameters similar to those of CsPb2Cl5, have been determined by Rietveld analysis. The optical band gap was obtained by UV-vis spectroscopy, and the band structure was further calculated by the full-potential method within the generalized gradient approximation. It was revealed that the band gap in CsPb2(Cl1- xBr x)5 solid solutions can be tuned over the range of 4.5-3.8 eV by anion substitution.

Role of spin-orbit interaction on the nonlinear optical response of CsPbCO3F using DFT.

We explore the effect of spin-orbit interaction (SOI) on the electronic and optical properties of CsPbCO3F using the full potential linear augmented plane wave method with the density functional theory (DFT) approach. CsPbCO3F is known for its high powder second harmonic generation (SHG) coefficient (13.4 times (d36 = 0.39 pm V-1) that of KH2PO4 (KDP)). Calculations are done for many exchange correlation (XC) potentials. After the inclusion of SOI, the calculated Tran-Blaha modified Becke-Johnson (TB-mBJ) band gap of 5.58 eV reduces to 4.45 eV in agreement with the experimental value. This is due to the splitting of Pb p-states. Importantly, the occurrence of a band gap along the H-A direction (indirect) transforms to the H-H (direct) high symmetry points/direction in the first Brillouin zone. We noticed a large anisotropy in the calculated complex dielectric function, absorption, and refractive index spectra. The calculated static birefringence of 0.1049 and 0.1057 (with SOI) is found to be higher than that of the other carbonate fluorides. From the Born effective charge (BEC) analysis we notice that the Cs atom shows a negative contribution to birefringence whereas Pb, C, and F atoms show a positive contribution. In addition, we have also calculated the nonlinear optical χ(-2ω;ω,ω) dispersion of a CsPbCO3F single crystal. We found that d11 = d12 = 4.35 pm V-1 at 1064 nm, which is 11.2 times higher than d36 of KDP. The origin of the highly nonlinear optical susceptibility dispersion of CsPbCO3F is explained. Overall, our results are in agreement with experiments and it is obvious from the present study that CsPbCO3F is a direct band gap, large second harmonic generation, and good phase matchable NLO crystal in the ultraviolet region.

Macroscopic Polarization Enhancement Promoting Photo- and Piezoelectric-Induced Charge Separation and Molecular Oxygen Activation.

Efficient photo- and piezoelectric-induced molecular oxygen activation are both achieved by macroscopic polarization enhancement on a noncentrosymmetric piezoelectric semiconductor BiOIO3 . The replacement of V5+ ions for I5+ in IO3 polyhedra gives rise to strengthened macroscopic polarization of BiOIO3 , which facilitates the charge separation in the photocatalytic and piezoelectric catalytic process, and renders largely promoted photo- and piezoelectric induced reactive oxygen species (ROS) evolution, such as superoxide radicals (. O2- ) and hydroxyl radicals (. OH). This work advances piezoelectricity as a new route to efficient ROS generation, and also discloses macroscopic polarization engineering on improvement of multi-responsive catalysis.

Synthesis, Structural, Thermal, and Electronic Properties of Palmierite-Related Double Molybdate α-Cs2Pb(MoO4)2.

Cs2Pb(MoO4)2 crystals were prepared by crystallization from their own melt, and the crystal structure has been studied in detail. At 296 K, the molybdate crystallizes in the low-temperature α-form and has a monoclinic palmierite-related superstructure (space group C2/m, a = 2.13755(13) nm, b = 1.23123(8) nm, c = 1.68024(10) nm, ß = 115.037(2)°, Z = 16) possessing the largest unit cell volume, 4.0066(4) nm3, among lead-containing palmierites. The compound undergoes a distortive phase transition at 635 K and incongruently melts at 943 K. The electronic structure of α-Cs2Pb(MoO4)2 was explored by using X-ray emission spectroscopy (XES) and X-ray photoelectron spectroscopy methods. For α-Cs2Pb(MoO4)2, the photoelectron core-level and valence-band spectra and the XES band representing the energy distribution of Mo 4d and O 2p states were recorded. Our results allow one to conclude that the Mo 4d and O 2p states contribute mainly to the central part and at the top of the valence band, respectively, with also significant contributions throughout the whole valence-band region of the molybdate under consideration.

Dispersion of linear, nonlinear optical susceptibilities and hyperpolarizability of C11H8N2O (o-methoxydicyanovinylbenzene) crystals.

Linear and nonlinear optical susceptibility dispersion and hyperpolarizability of C(11)H(8)N(2)O, o-methoxydicyanovinylbenzene, crystals were performed by means of density functional theory (DFT). The exchange and correlation potential was described within a framework of the local density approximation (CA-LDA) and gradient approximation (GGA) based on exchange-correlation energy optimization to calculate the total energy. Engel-Vosko generalized gradient approximation (EV-GGA) and the modified Becke-Johnson potential (mBJ) were used for the electronic crystal structure and optical susceptibility dispersion calculations. We have established systematically increasing energy gap from 2.25 eV (LDA), 2.34 eV (GGA), 2.50 eV (EVGGA), and 2.96 eV (mBJ). The crystal possesses a direct band gap which is an important key factor to make the crystal optically active with high linear and nonlinear optical susceptibilities and hyperpolarizability. Additionally, the studied crystal has a considerable anisotropy of birefringence which is necessary for phase matching conditions during the optical second harmonicexperiments. We have found that the theoretically evaluated second harmonic generation achieves about 5.8 × 10(-8) esu in good agreement with the experimental value (4.9 × 10(-8) esu). Additionally, we have found that our calculated value of ß(222) is about 2.3 × 10(-30) esu at zero energy and 6.6 × 10(-30) esu at λ = 1.064 µm. We should emphasize that our calculated value of ß(222) (6.60 × 10(-30) esu at λ = 1.064 µm) shows better agreement with the experimental data (5.04 × 10(-30) esu at λ = 1.064 µm) than other calculations.

An ab initio density functional study of the optical functions of 9-Methyl-3-Thiophen-2-YI-Thieno [3,2e] [1,2,4] Thriazolo [4,3c] Pyrimidine-8-Carboxylic Acid Ethyl Ester crystals.

An ab initio investigation of the optical constants of 9-Methyl-3-Thiophen-2-YI-Thieno [3,2e] [1,2,4] Thriazolo [4,3c] Pyrimidine-8-Carboxylic Acid Ethyl Ester crystal is performed within a framework of local density approximation (LDA), and the Engel-Vosko generalized gradient approximation (EV-GGA) exchange correlation potentials. It is established that there are two independent molecules (A and B) exhibiting different intra-molecular interactions: C-H⋯O (A) and C-H⋯N (B). These intra-molecular interactions favor stabilization of the crystal structure for molecules A and B. It should be emphasized that there exist remarkable π-π interactions between the pyrimidine rings of the two neighbors B molecules giving extra strengths and stabilizations to the superamolecular structure. These different intra-molecular interactions C-H⋯O (A) and C-H⋯N (B) and the π-π interaction between the pyrimidine rings of the two neighbors B molecules give principal contribution to dispersion of optical properties. With a view to seek deeper insight into the electronic structure, the optical properties were investigated. Our calculations show that the optical constants are very anisotropic. The EVGGA calculation shows a blue spectral shift of around 0.024 eV with significant changes in the spectra compared to the LDA calculation. The observed spectral shifts are in agreement with the calculated band structure and corresponding electron density of states.

Optical and photoconductivity spectra of novel Ag2In2SiS6 and Ag2In2GeS6 chalcogenide crystals.

Complex spectral studies of near-band gap and photoconductive spectra for novel Ag(2)In(2)SiS(6) and Ag(2)In(2)GeS(6) single crystals are presented. The spectral dependences of photoconductivity clearly show an existence of spectral maxima within the 450 nm-540 nm and 780 nm-920 nm. The fundamental absorption edge is analyzed by Urbach rule. The origin of the spectral photoconductivity spectral maxima is discussed. Temperature dependences of the spectra were done. The obtained spectral features allow to propose the titled crystals as photosensors. An analysis of the absorption and photoconductivity spectra is given within a framework of oversimplified spectroscopic model of complex chalcogenide crystals.

First-principles calculations of structural, elastic, electronic, and optical properties of perovskite-type KMgH3 crystals: novel hydrogen storage material.

We report a first-principles study of structural and phase stability in three different structures of perovskite-types KMgH(3) according to H position. While electronic and optical properties were measured only for stable perovskite-type KMgH(3), our calculated structural parameters are found in good agreement with experiment and other theoretical results. We also study the electronic charge density space distribution contours in the (200), (101), and (100) crystallographic planes, which gives better insight picture of chemical bonding between K-H, K-Mg-H, and Mg-H. Moreover, we have calculated the electronic band structure dispersion, total, and partial density of electron states to study the band gap origin and the contribution of s-band of H, s and p-band of Mg in the valence band, and d-band of K in the conduction band. Furthermore, optical features such as dielectric functions, refractive indices, extinction coefficient, optical reflectivity, absorption coefficients, optical conductivities, and loss functions of stable KMgH(3) were calculated for photon energies up to 40 eV.

Dispersion of linear and nonlinear optical susceptibilities and the hyperpolarizability of 3-methyl-4-phenyl-5-(2-pyridyl)-1,2,4-triazole.

As a starting point for our calculation of 3-methyl-4-phenyl-5-(2-pyridyl)-1,2,4-triazole we used the XRD data obtained by C. Liu, Z. Wang, H. Xiao, Y. Lan, X. Li, S. Wang, Jie Tang, Z. Chen, J. Chem. Crystallogr., 2009 39 881. The structure was optimized by minimization of the forces acting on the atoms keeping the lattice parameters fixed with the experimental values. Using the relaxed geometry we have performed a comprehensive theoretical investigation of dispersion of the linear and nonlinear optical susceptibilities of 3-methyl-4-phenyl-5-(2-pyridyl)-1,2,4-triazole using the full potential linear augmented plane wave method. The local density approximation by Ceperley-Alder (CA) exchange-correlation potential was applied. The full potential calculations show that this material possesses a direct energy gap of 3.4 eV for the original experimental structure and 3.2 eV for the optimized structure. We have calculated the complex's dielectric susceptibility ε(ω) dispersion, its zero-frequency limit ε(1)(0) and the birefringence. We find that a 3-methyl-4-phenyl-5-(2-pyridyl)-1,2,4-triazole crystal possesses a negative birefringence at the low-frequency limit Δn(0) which is equal to about -0.182 (-0.192) and at λ = 1064 nm is -0.193 (-0.21) for the non-optimized structure (optimized one), respectively. We also report calculations of the complex second-order optical susceptibility dispersions for the principal tensor components: χ(ω), χ(ω) and χ(ω). The intra- and inter-band contributions to these susceptibilities are evaluated. The calculated total second order susceptibility tensor components at the low-frequency limit |χ(0)| and |χ(ω)| at λ = 1064 nm for all the three tensor components are evaluated. We established that the calculated microscopic second order hyperpolarizability, ß(ijk), the vector component along the dipole moment direction, at the low-frequency limit and at λ = 1064 nm, for the dominant component |χ(ω)| is 4.99 × 10(-30) esu (3.4 × 10(-30) esu) and 7.72 × 10(-30) esu (5.1 × 10(-30) esu), respectively for the non-optimized structure (optimized structure).

Spectral emission properties of 4-aryloxy-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinolines.

Spectral emission properties of novel 4-aryloxy-1H-pyrazolo[3,4-b]quinolines were investigated. All of the compounds exhibit strong blue luminescence in the solution and in the solid state as well. Pyrazoloquinolines were used as dopants in PVK matrices in electroluminescent devices with ITO/PVK:PQ/Ca/Al light emitting diode configuration.

Copper-intercalated TiS2: electrode materials for rechargeable batteries as future power resources.

We report results of first-principles total-energy calculations of structural and optical properties of the TiS(2) single crystals intercalated with copper. Calculations have been performed using an all-electron, full potential, linearized, augmented, plane-wave method based on density functional theory using generalized gradient approximation for the exchange correlation energy functional. To complete the fundamental characteristics of these compounds, we have calculated and analyzed their linear optical susceptibilities. We demonstrate the efficiency of using a full potential on the band structure, density of states, and the optical properties. We compare our results of the intercalated Cu in different sites and concentrations with the host TiS(2) compound to ascertain the effect of Cu intercalation on the electronic and optical properties. Our calculations have shown that the electronic and optical properties are influenced significantly by the location and concentration of the Cu intercalate in the host compound. The Cu-s and Cu-p bands are very broad and do not contribute much to the density of states. The density of states and the electron charge density show that all Ti-Ti and S-S bonds are basically of ionic character and that Ti-S bonds are of covalent character. No covalent electrons are found between Cu and S atoms; that is, no covalent bond exists between the Cu and S atoms. The Cu atoms are ionic in the intercalated compounds.

Dispersion of linear and nonlinear optical susceptibilities in calcium neodymium oxyborate Ca4NdO(BO3)3-LDA versus GGA.

We have performed ab inito theoretical calculations of the electronic structure and the linear and nonlinear optical susceptibilities for calcium neodymium oxyborate Ca4NdO(BO3)3 using two approximations for the exchange correlation (XC) potentials, the local density approximation (LDA) and the generalized gradient approximation (GGA). Our calculations show that this compound is metallic-like, with density of states at the Fermi energy E(F), N(E(F)), of 5.95 and 10.33 states/Ry-cell or bare electronic specific heat coefficients of 1.03 and 1.79 mJ/mol-K2 for LDA and GGA, respectively. The overlap between the valence and conduction bands is strong, resulting in metallic behavior. We found that Nd-s/p/d, Ca-s/p, B-p, and O-s/p states controlled the overlapping around E(F). The effect of LDA and GGA on the band structure, density of states, and linear optical properties is very small, while for the nonlinear optical properties, it is very pronounced. Our calculations show that χ(111)(2)(ω) is the dominant component for both LDA and GGA. We find opposite signs of the contributions of the 2ω and 1ω inter/intraband to the real and imaginary parts for the dominant component throughout the wide optical frequency range.

UV-vis absorption spectra of 1,4-dialkoxy-2,5-bis[2-(thien-2-yl)ethenyl]benzenes.

Complex theoretical and experimental studies and quantum-chemical calculations were applied to study the UV-vis spectroscopic features of the novel compounds: three stereoisomers of 1,4-diethoxy-2,5-bis[2-(5-methylthien-2-yl)ethenyl]benzene (A-C) and E,E isomer of 1,4-diisopropoxy-2,5-bis[2-(thien-2-yl)ethenyl]benzene (D). These structures are the derivatives of 2,5-bis[2-(thien-2-yl)ethenyl]benzene, and belong to a group of thienyl-PPV family that are able to polymerize due to the presence of pi-conjugated bonding system. It was established that such compounds during electropolymerization are strongly dependent on their stereochemistry and on the eventual presence of substituents in alpha-positions of the tiophene ring. We have obtained a good agreement between the theoretically simulated optical within a framework of TDDFT approach and experimentally measured data. Influence of PMMA polymer matrices on the UV-vis spectra is explored. It is shown that a red wavelength spectral shift is observed only for D compounds and agreement between calculated and experimental spectral data is sufficiently good. This may indicate on different influence of local polymer matrix field on the spectral behaviors of the chromophores with different stereochemistry.

FP-APW+lo calculations of the electronic and optical properties of alkali metal sulfides under pressure.

The electronic and optical properties of M(2)S (M = Li, Na, K and Rb) compounds in the cubic antifluorite structure have been calculated, using a full relativistic version of the full-potential augmented plane-wave plus local orbitals method based on density functional theory, within both the local density approximation (LDA) and the generalized gradient approximation (GGA). Moreover, the Engel-Vosko GGA formalism (EV-GGA) is applied so as to optimize the corresponding potential for band structure calculations. The calculated equilibrium lattices and bulk moduli are in good agreement with the available data. Band structure, density of states, electron charge density and pressure coefficients of energy gaps are given. Results obtained for band structure using EV-GGA are larger than those with LDA and GGA. It is found that the spin-orbit coupling lifts the triple degeneracy at the Γ point and the double degeneracy at the X point. The analysis of the electron charge density shows that the M-S bonds have a significant ionic character. The complex dielectric functions ε(2)(ω) for alkali metal sulfides were calculated for radiation up to 30 eV and the assignment of the critical points to the band structure energy differences at various points of the Brillouin zone was made. The pressure and volume dependence of the static dielectric constant and the refractive index are calculated.