Site occupancy of Fe2+, Fe3+ and Ti4+ in titanomagnetite determined by valence-difference contrast in synchrotron X-ray resonant scattering.

A synchrotron X-ray diffraction study of a single crystal of titanomagnetite shows that the cation distribution of Fe2+, Fe3+ and Ti4+ is of the inverse-spinel type. The valence-difference contrast (VDC) method of resonant scattering was applied at a wavelength of λ = 1.7441 Š(E = 7.1085 keV) within the pre-edge of the Fe K absorption spectrum, utilizing the large difference in the real part of anomalous scattering factors, between -7.45 and -6.50, for Fe2+ and Fe3+, respectively. The most plausible atomic arrangement in Ti0.31Fe2.69O4 obtained from our analysis is [Fe3+1.00]A[Fe3+0.38Fe2+1.31Ti4+0.31]BO4, where A and B in an AB2O4-type structure correspond to the tetrahedral and octahedral sites, respectively. This result suggests that titanomagnetite has the complete inverse-spinel structure continuously from the end-member of magnetite, even in the case of relatively high Ti content. The physical properties may be described by the Néel model, which claims that Fe3+ preferentially occupies the tetrahedral site, within a Ti-poor half-region of the solid solution. Based on the ordering scheme the magnetic structure of titanomagnetite is considered to be analogous to that of magnetite. The combination of circularly polarized X-rays and a horizontal-type four-circle diffractometer used in this VDC technique has the advantage of increasing the experimental accuracy and freedom with the simultaneous reduction of experimental noise.

Positive Rate and Utility of Blood Culture among Nursing and Healthcare-associated Pneumonia Inpatients: A Cross-sectional Study.

Objective Although blood cultures to identify the presence of bacteremia are recommended for nursing- and healthcare-associated pneumonia (NHCAP), the incidence of true bacteremia and the relationship between true bacteremia and the outcome remain unclear. Physicians can therefore sometimes be confused regarding whether or not blood cultures should be obtained for NHCAP patients. This study assessed the incidence of true bacteremia and the relationship between true bacteremia and the outcome of NHCAP in a Japanese hospital setting. Methods We retrospectively analyzed NHCAP patients hospitalized between April 2016 and March 2021. The primary outcome was the incidence of true bacteremia in blood cultures. The incidence of true bacteremia was also examined according to quick Sequential Organ Failure Assessment (qSOFA) and A-DROP scores. In addition, we compared the incidence of true bacteremia between survivors and non-survivors. Results In total, 205 patients were included in this study. Blood cultures were obtained from 150 of the 205 patients (73.2%). Positive blood cultures were detected in 26 patients (17.3%), of which only 8 cases (5.3%; 95% confidence interval, 2.3-10.2%) were considered true bacteremia. Trend analyses for the incidence of true bacteremia according to qSOFA and A-DROP scores did not show any statistically significant results (p=0.49 for qSOFA; p=0.14 for A-DROP). The proportion of true bacteremia cases did not differ significantly between survivors and non-survivors. Conclusions The incidence of true bacteremia among NHCAP patients was very low. A strategy for determining indications for obtaining blood cultures from NHCAP patients needs to be established.

High-Selectivity imaging of the closed fatigue crack due to thermal environment using surface-acoustic-wave phased array (SAW PA).

Crack closure can cause the underestimation or misdetection of fatigue cracks in ultrasonic testing (UT). Fatigue-crack closure due to an environmental factor, i.e., high temperature, was found in eddy current testing (ECT), which is used to inspect the vicinity of surfaces. However, its effect and countermeasures have yet to be examined in UT. In this study, we examined the fatigue-crack closure induced by heat processing using a surface-acoustic-wave phased array (SAW PA). SAW PA is a phased-array imaging method using Rayleigh waves, which can sensitively visualize defects in the vicinity of surfaces. As a result, the intensity of crack responses visualized by SAW PA markedly decreased after the heat processing of a fatigue-crack specimen. Furthermore, we demonstrated that the combination of SAW PA with a crack opening method, global preheating and local cooling (GPLC), and a load difference phased array (LDPA) is useful for the high-selectivity imaging of closed fatigue cracks. We also discussed a possible mechanism of the fatigue-crack closure induced by heat processing.

A case of community-onset Acinetobacter pneumonia in a healthy person.

A 56-year-old woman with fever, sore throat and productive cough was referred to our hospital, where mild community-acquired pneumonia was diagnosed. Sputum smears revealed Gram-negative coccobacilli. Treatment with ceftriaxone was initiated, but symptoms continued without progression to respiratory failure or bacteremia. As sputum cultures identified Acinetobacter baumannii, antibiotics were changed to levofloxacin, resulting in complete remission. A. baumannii is a very rare cause of community-acquired pneumonia in Japan. However, in cases of pneumonia where Gram-negative coccobacilli are identified and prove resistant to initial treatment, the possibility of A. baumannii pneumonia should be kept in mind even for healthy subjects with low severity score.