Efficacy of spectral presaturation of inversion recovery in evaluating delayed myocardial enhancement

OBJECTIVE: Delayed myocardial enhancement is caused by a variety of cardiovascular diseases. The extent of the enhanced area has been examined by the inversion recovery (IR) method, whereby at the inversion time (TI), normal myocardium shows a low signal intensity. In this sequence, as pericardial fat shows a very high intensity, a delayed enhancement just below the pericardium may be indistinct. To improve the accuracy of delayed myocardial enhancement, we employed the spectral presaturation of inversion recovery (SPIR) method. MATERIALS AND METHODS: Thirty-five patients with symptoms of cardiovascular disease aged between 36 and 80 years old (mean age, 62 years old) were investigated. Thirty were men and five were women. Inversion recovery and SPIR images were obtained 25 min after initial administration of a gadolinium-based contrast material. Each TI, when the signal intensity of the normal myocardium was null, was determined by images obtained at serial different TIs. A radiologist and a cardiologist examined each image by a consensus reading. The extent of myocardial enhancement was described as none, subendocardial, transmural and a random pattern in each case. Images were ranked over three levels and were based on whether myocardial enhancement could be easily detected or whether the contour of the myocardium was visualized precisely. Student's t-test was conducted to compare the quality of two sequences in all patients and in 22 patients who showed delayed myocardial enhancement. RESULTS: The imaging quality in evaluating delayed myocardial enhancement in all patients was superior with IR compared with SPIR, although it was not statistically significant. The imaging quality in the patients with delayed myocardial enhancement was similar between SPIR and IR. SPIR was superior to the IR sequence in two of the four patients who exhibited transmural enhancement. CONCLUSION: SPIR exhibited equivalent image quality to IR in evaluating delayed myocardial enhancement. As it has the potential advantage in patients with rich adipose tissue surrounding the myocardium, it can be an alternative sequence to evaluate myocardial viability.     

Degradation of fenitrothion by ultrasound/ferrioxalate/UV system

The sonochemical photodegradation of fenitrothion, which is one of phosphorothiate insecticides, was carried out in the presence of Fe(III) and oxalate. The degradation rate was strongly influenced by initial concentrations of Fe(III) and oxalate. An initial fenitrothion concentration of 10 mg L⁻¹ was completely degraded after 30 min at pH 6 under the optimum conditions. Therefore, the photo-Fenton reaction combined with sonication in the presence of oxalate was available around neutral pH. The decrease of TOC as a result of mineralization of fenitrothion was observed during ultrasound (US)/ferrioxalate/UV process. In addition, the formations of nitrite and sulfate ions as end-products were observed during this degradation system. The decomposition of fenitrothion gave two kinds of intermediate products. The degradation mechanism of fenitrothion was proposed on the base of the evidence of the identified intermediates. Based on these results, US/ferrioxalate/UV system could be useful technology for the treatment of wastewater containing fenitrothion.     

Microstructural analysis of La2/3 − xLi3xTiO3 single crystals and quenched samples observed by high resolution transmission electron microscopy

The La ordering and domain structures of La_2/3 ? xLi_3xTiO₃ single crystals and quenched samples have been observed by high resolution electron microscopy. In single crystals, the grown single crystals are not real single crystals with mono-domain, but crystals with 90° oriented domains with 20–100 nm sizes. A remarkable difference of the domain size between polycrystals and single crystals has not been observed at the same composition. In quenched samples, the La disordering has been observed. Furthermore, domain structures of quenched samples are different from those of furnace-cooled ones. Domain structures change with the La disordering. The understanding of microstructures is necessary to clarify the Li-ion conduction mechanism.     

Nodal versus nodeless behaviors of the order parameters of LiFeP and LiFeAs superconductors from magnetic penetration-depth measurements

High-precision measurements of magnetic penetration depth λ in clean single crystals of LiFeAs and LiFeP superconductors reveal contrasting behaviors. In LiFeAs the low-temperature λ(T) shows a flat dependence indicative of a fully gapped state, which is consistent with previous studies. In contrast, LiFeP exhibits a T-linear dependence of superfluid density infinity λ(-2), indicating a nodal superconducting order parameter. A systematic comparison of quasiparticle excitations in the 1111, 122, and 111 families of iron-pnictide superconductors implies that the nodal state is induced when the pnictogen height from the iron plane decreases below a threshold value of ~1.33 ?.     

Photocatalytic activity and related surface properties of transparent ZnO films prepared by a low-temperature aqueous route

Transparent ZnO were prepared using solutions with various trisodium citrate concentrations by a spin-spray method at 90°C. The morphological and structural characteristics, as well as photocatalytic activity of the resulting ZnO films were examined with respect to the added trisodium citrate concentration. Photocatalytic activities of the ZnO films were evaluated from photodecomposition of methylene blue (MB) in aqueous solution. With increasing citrate concentrations, the ZnO films came to have higher transmittances in visible region but lower MB decomposition rate. Both high transmittance and high photocatalytic activity were achieved in the ZnO film prepared in the citrate concentration of 0.5 mm. The possible mechanism for the difference in photocatalytic activity by the samples prepared with the various concentrations of citrate was discussed from the viewpoint of film texture, crystal orientation and surface chemical state.     

The photoelectron spectra of the OH and OD radicals

He(I) photoelectron spectra of the hydroxyl radical show ionizations corresponding to the production of OH⁺ (OD⁺) in the states X ³Σ^? and ¹Δ at ionization potentials of 13.01 eV and 15.20 eV respectively. The excitation energy of the ¹Δ state is in very good agreement with that predicted by calculation and experiment; vibrational spacings in the X ³Σ^? state agree with emission spectroscopic data.     

Direct observations of La ordering and domain structures in La0.61Li0.17TiO3 by high resolution electron microscopy

La_0.61Li_0.17TiO₃ microstructures have been studied by high resolution electron microscopy. A local lattice distortion occurs in the vicinity of the domain boundary region due to the twin with an angle of 89°. The average domain size of La_0.61Li_0.17TiO₃ is greater than 20 nm. The domain size and structures of La_0.61Li_0.17TiO₃ differ greatly from those of La-poor compounds, such as La_0.55Li_0.35TiO₃. At a nanoscopic level, microdomains of 20–100 nm in size construct a two-dimensional structure in La-rich compounds, while microdomains of 5–10 nm in size construct a three-dimensional structure in La-poor compounds. In addition, the Li-ion conduction mechanisms for La-rich and La-poor compounds are two- and three-dimensional, respectively.     

Zeeman levels with exotic field dependence in the high field phase of an S=1 Heisenberg antiferromagnetic chain

We have performed electron spin resonance measurements over a wide frequency and magnetic field range on a single crystal of the S=1 quasi-one-dimensional Heisenberg antiferromagnet Ni(C5H14N2)2N3(PF6). We observed gapped excitation branches above the critical field H(c) where the Haldane gap closes. These branches are analyzed by a phenomenological field theory using the complex-field phi(4) model. A satisfactory agreement between experiment and theory is obtained.