E12 Values Research Articles

Software for standard-based analysis of thick target PIGE data

Software, “SyrPIGE”, has been developed to perform particle induced γ-ray emission (PIGE) data analysis of thick targets relying on a standard-based method. It allows self-consistent and direct analysis of PIGE data considering easy calibration of PIGE spectra, on-screen identification of every γ-ray line, manual input or evaluation of E12 values for every element at established γ-ray energies, direct generation of stopping power data based on built-in electronic stopping power calculations for protons, ability to compare results with standards and batch mode analysis capability. The software was tested on standards and showed reliable and consistent results, with PIGE data analysis performed in a very short time compared with time-consuming traditional analysis.

Piezoelectricity in monolayer BxCyNz structures: A first principles study

A new family of layered two-dimensional materials, borocarbonitrides (BxCyNz), is derived from the graphene and h-BN structures. Although there is quite a lot of studies about the synthesis, characterization, electronic and structural properties of BxCyNz structures, there is a lack of information about their piezoelectric capabilities in the literature. First, twenty different BxCyNz formations were taken into consideration and the structures with space group symmetry that could show piezoelectricity were determined among them. Then, density functional theory based theoretical calculations were used to investigate the electronic, elastic, and piezoelectric properties of these materials. Dynamical stability of these materials were investigated via phonon calculations. To compare the effect of the selected method and the functional on piezoelectric stress and strain coefficients, LDA and PBE functionals were used crosswise via finite displacement (FD) and density functional perturbation theory (DFPT) methods. DFPT calculations in which PBE and LDA were used showed that e11 and e12 piezoelectric stress coefficient results do not affected by the selected function. Although, FD calculations for e12 values give close results to DFPT methods, e11 values calculated via this method differs from the other two by %10–30. It was observed that BxCyNz structures are promising piezoelectric materials which their piezoelectricity can be tuned by changing x, y, and z ratios and atomic conformations. The effect of atomic bonding types on the piezoelectric properties of these materials were revealed. The lowest e11 and e12 piezoelectric coefficients calculated for the BCN2 structure, which has an undesired N-N bond. The highest relaxed-ion e11 values were calculated for BC2N structures,5 × 10−10 C/m. B2CN structure gives the highest relaxed-ion e12 value 5.5 × 10−10 C/m. B3C2N3 formations give close results to each other for e11 and e12 values around 4.5 × 10−10 C/m. Our calculations reveal that BxCyNz structures are strong candidates for future atomically thin piezoelectric applications.

Relationship Between Distance and Change in Surface ECG Morphology During Pacemapping as a Guide to Ablation of Ventricular Arrhythmias: Implications for the Spatial Resolution of Pacemapping.

Pacemapping is used to localize the exit site of ventricular arrhythmia. Although the relationship between distance and change in QRS morphology is its basis, this relationship has not been systematically quantified. Patients (n=68) undergoing ventricular arrhythmia ablation between March 2012 and July 2013 were recruited. Pacemapping was targeted to areas of voltage >0.5 mV. Linear mixed-effects models were constructed of distance against morphology difference measured by the root mean square error sum across all 12 ECG leads (E12). Forty of 68 (58%) patients had structural heart disease, and 21/40 (53%) patients were ischemic. Nine hundred thirty-five pacing points were collected, generating 6219 pacing site pair combinations (3087 [50%] ventricular bodies, 756 [12%] outflow tract, and 162 [3%] epicardial). In multivariable analysis, increase in E12 was predicted by increasing distance (0.07 per mm; 95% confidence interval 0.07-0.08; P<0.001). Compared with the left ventricle, E12 values were lower in the right ventricle (P=0.037) and left ventricular outflow tract (P<0.001) and higher in left ventricle-right ventricle pairs (P=0.021) and left ventricular epicardium (P=0.08). There was no difference in E12 in the right ventricular outflow tract compared with the right-left ventricular outflow tract (P=0.75) pairs. Structural heart disease or inadvertent pacing in scar was not associated with changes in E12; however, the presence of latency and split potentials were associated with higher and lower E12 values, respectively (P<0.001). A robust positive relationship exists between distance and QRS morphological change when restricting pacing points to areas of voltage >0.5 mV. Significant differences in the spatial resolution of pacemapping exist within the heart.

Chemistry of Azopyrimidines. Part III. Synthesis, Spectral Characterization and Electrochemical Studies of Arylazopyrimidine Complexes of Palladium(II) and Catecholato Derivatives

2-(Phenylazo)pyrimidine (papm), 2-(p-tolylazo)pyrimidine (p-tapm), 2-(p-chlorophenylazo)pyrimidine (p-Clpapm) are used as N,N′-chelators. They are called arylazopyrimidines and abbreviated in general as aapm (1). They were reacted with cis-Pd(MeCN)2Cl2 to yield orange-red complexes of the type Pd(aapm)Cl2 (2). Upon reaction with catechols in the presence of triethylamine (Et3N), Pd(aapm)Cl2 yielded the mixed-ligand complexes [Pd(aapm)(O,O)] where O,O = pyrocatecholate [cat, (3)], 4-tert-butylcatecholate [tbcat, (4)], 3,5-di-tert-butylcatecholate [dtbcat, (5)] and tetrachlorocatecholate [tccat, (6)]. The complexes were characterised by elemental analyses, IR spectra, UV-VIS spectra and 1H NMR spectra. The redox properties were examined with cyclic voltammetry. [Pd(aapm)(O,O)] exhibits four successive redox responses and the E12 values are highly sensitive to the nature of the substituents. The electronic spectra of [Pd(aapm)(O,O)] exhibit ligand-to-ligand charge transfer transitions and are different from those of Pd(aapm)Cl2 The band position is largely dependent on the substituent type of the catechol frame and is tentatively assigned to the 3bi (cat)→π*(aapm) transition.

Electrochemical investigation of coordination compounds: I. The oxidation—reduction mechanism of CoI, RhI and IrI systems containing trivalent phosphorus and carbonyl ligands

The polarographic reduction of complexes in the +I state, obtained by the reactions of phosphorus ligands with [Co(CO)4]2, [RhCl(CO)2]2 and [Ir(CO)3Cl]n, has been studied. The reduction has been shown to proceed in a two-electron step leading to anionic complexes in the -I state, which react with the starting materials to form zero-valent complexes. For the complexes MX(CO)L2 (M = Rh, Ir) The E12 values are more negative when the basicity of the ligand L and the electronegativity of X increase.

Electrical Transport Properties of Ga(AsxSb1−x) and (GaxIn1−x)Sb Alloys under Hydrostatic Pressure

Homogeneous polycrystalline n type samples of the alloys Ga(AsxSb1−x) and (GaxIn1−x)Sb have been prepared from a stoichiometric melt by directional freezing methods. Room temperature measurements of electrical conductivity and Hall coefficient as a function of hydrostatic pressure up to 12 kbars have been made on samples of different composition by means of the van der Pauw technique, all specimens used in the measurements being carefully selected to avoid the presence of grain boundary effects. The experimental curves of conductivity and Hall coefficient as a function of pressure have been fitted to a two conduction band model with various band parameters taken as adjustable. The curves thus fitted give consistent values of E12, the energy separation of the two bands, as a function of x. For (GaxIn1−x)Sb, the E12 values are in good agreement with those obtained previously from measurements as a function of temperature, no previous values having been published for Ga(AsxSb1−x). Approximate values for the coupling coefficient D12 of the alloys are also obtained.

The role of biotin and vitamin B 12 coenzyme in propionate metabolism

The one-electron reduction potentials for the alkylcobalamins, R = CH3, CH2CH3, n-propyl, isobutyl, neopentyl and deoxyadenosyl, were examined by differential pulse polarography in 1:1 DMF:H2O (μ = 0.10 LiClO4) at 24.6 °C. The E12 values for the couple RCo + e− ⇄ RCo· (RCo = alkylcobalamin) were found to be −1.60 V, R = CH3; −1.54 V, R = CH2CH3; 1.55 V, R = n-propyl; −1.48 V, R = isobutyl; −1.38 V, R = neopentyl; −1.35 V, R = deoxyadenosyl versus SCE. E12 correlates linearly with the Taft steric parameter, Es; a new Es value for the deoxyadenosyl functional unit is estimated to be −2.03 from this relationship. A moderate solvent influence was observed by replacing H2O with D2O for methylcobalamin (E12 = −1.68 V versus SCE) and for deoxyadenosylcobalamin (coenzyme B12) (−1.43 V). This suggests that solvation effects are about the same for alkylcobalamins compared to methylcobalamin and therefore do not account for the 0.22 V more negative reduction potential of methylcobalamin. The gradation in E12 starting with methylcobalamin and continuing through the alkylcobalamin series may reflect changes in the axial ligand distances which modulate the energy of the lowest σ type MO (LUMO) of these complexes.