Superstructure of Fe5-xGeTe2 Determined by Te K-Edge Extended X-ray Absorption Fine Structure and Te Kα X-ray Fluorescence Holography.

The local structure of the two-dimensional van der Waals material, Fe5-xGeTe2, which exhibits unique structural/magnetic phase transitions, was investigated by Te K-edge extended X-ray absorption fine structure (EXAFS) and Te Kα X-ray fluorescence holography (XFH) over a wide temperature range. The formation of a trimer of Te atoms at low temperatures has been fully explored using these methods. An increase in the Te-Fe distance at approximately 150 K was suggested by EXAFS and presumably indicates the formation of a Te trimer. Moreover, XFH displayed clear atomic images of Te atoms. Additionally, the distance between the Te atoms shortened, as confirmed from the atomic images reconstructed from XFH, indicating the formation of a trimer of Te atoms, i.e., a charge-ordered superstructure. Furthermore, Te Kα XFH provided unambiguous atomic images of Fe atoms occupying the Fe1 site; the images were not clearly observed in the Ge Kα XFH that was previously reported because of the low occupancy of Fe and Ge atoms. In this study, EXAFS and XFH clearly showed the local structure around the Te atom; in particular, the formation of Te trimers caused by charge-ordered phase transitions was clearly confirmed. The charge-ordered phase transition is fully discussed based on the structural variation at low temperatures, as established from EXAFS and XFH.

Pressure Dependence of the Structural and Superconducting Properties of the Bi-Based Superconductor Bi2Pd3Se2.

The structural and superconducting properties of the Bi-based compound Bi2Pd3Se2 were investigated over a wide pressure range. The prepared Bi2Pd3Se2 sample was a superconductor with a superconducting transition temperature, Tc, of approximately 3.0 K, which differed from a previous report (Tc of less than 1.0 K). At ambient pressure, the powder X-ray diffraction (XRD) pattern of the Bi2Pd3Se2 sample was consistent with that previously reported for Bi2Pd3Se2. The Rietveld method was used to refine the crystal structure, which had a space group of C2/m (No. 12), as reported previously. This compound showed no clear anomaly due to the charge-density-wave (CDW) transition, as seen from the temperature dependence of magnetic susceptibility. However, the temperature dependence of electrical resistivity indicated a clear anomaly, presumably because of the CDW transition in the low-pressure range; the CDW transition temperature was approximately 230 K. The XRD patterns of the Bi2Pd3Se2 sample were measured at 0.160-22.7 GPa, and the patterns were well analyzed by both the Le Bail and Rietveld refinement methods, showing no structural phase transitions in the above pressure range. The pressure dependence of Tc of Bi2Pd3Se2 was recorded based on the temperature dependence of the electrical resistance, which showed an almost constant Tc at 0-13.7 GPa, and the Tc-pressure (p) behavior was fully discussed.

Observation of the Superstructure in Fe5-xGeTe2 by X-ray Fluorescence Holography.

Fe5-xGeTe2 is a two-dimensional van der Waals material that exhibits ferromagnetic order with a high Curie temperature (TC) of around room temperature. In addition to TC, two magnetic transitions occur with decreasing temperature, and a charge-ordered state is observed at low temperatures. We employed Ge Kα X-ray fluorescence holography (XFH) for Fe5-xGeTe2 to directly investigate the local structure in the charge-ordered state, i.e., the 3×3 superstructure. The Ge Kα XFH results revealed local atomic structures around the Ge atom, thus clarifying the simultaneous locations and arrangements of the Te, Fe, and Ge atoms. The atomic positions relative to the Ge atom are useful for understanding the coexistence of the ideal 1 × 1 structure and 3×3 superstructure found in the charge-ordered state.

Second victim syndrome in intensive care unit healthcare workers: A systematic review and meta-analysis on types, prevalence, risk factors, and recovery time.

INTRODUCTION: Patient safety incidents, including medical errors and adverse events, frequently occur in intensive care units, leading to a significant psychological burden on healthcare workers. This burden results in second victim syndrome, which impacts the psychological and psychosomatic well-being of these workers. However, a systematic review focusing specifically on this condition among intensive care unit healthcare workers is lacking. Therefore, we aimed to conduct a systematic review and meta-analysis to examine the occurrence of second victim syndrome among intensive care unit healthcare workers, including the types, prevalence, risk factors, and recovery time associated with this condition. METHODS: We conducted a comprehensive search of the MEDLINE, CINAHL, PsycINFO, and Igaku Chuo Zasshi databases. The eligibility criteria encompassed retrospective, prospective, and cross-sectional studies and controlled trials, with no language restrictions. Data on the type, prevalence, risk factors, and recovery time of second victim syndrome were extracted and pooled. Prevalence estimates from the included studies were combined using a random-effects meta-analytic model. RESULTS: Of the 2,245 records retrieved, 16 potentially relevant studies were identified. Following full-text evaluation, five studies met the inclusion criteria and were included in the review. The findings revealed that 58% of intensive care unit healthcare workers experienced second victim syndrome. Frequent symptoms included guilt (12-68%), anxiety (38-63%), anger at self (25-58%), and lower self-confidence (7-58%). However, specific risk factors exclusive to intensive care unit healthcare workers were not identified in the review. Furthermore, approximately 20% of individuals took more than a year to recover or did not recover at all from the second victim syndrome. CONCLUSIONS: Thus, this condition is prevalent among intensive care unit healthcare workers and may persist for extended periods, potentially exceeding a year. The risk factors for second victim syndrome in the intensive care unit setting are unclear and require further investigation.

Pressure Dependence of Superconductivity in a Charge-Density-Wave Superconductor Bi2Rh3Se2.

The structural and superconducting properties of a Bi-based compound, Bi2Rh3Se2, are investigated over a wide pressure range. Bi2Rh3Se2 is a superconductor with a superconducting transition temperature, Tc, of 0.7 K. This compound is in a charge-density-wave (CDW) state below 240 K, which implies the coexistence of superconducting and CDW states at low temperatures. Here, the superconducting properties of Bi2Rh3Se2 are studied from the perspective of the temperature dependence of electrical resistance (R) at high pressures (p's). The pressure dependence of Tc of Bi2Rh3Se2 shows a slow increase in Tc at 0-15.5 GPa, and the Tc slowly decreases with pressure above 15.5 GPa, which is markedly different from that of normal superconductors because the value of Tc should simply decrease owing to the decrease in density of states (DOS) on the Fermi level, N(εF), driven by a simple shrinkage of the lattice under pressure. To ascertain the origin of such a dome-like Tc-p behavior, the crystal structure of Bi2Rh3Se2 was explored over a wide pressure range of 0-20 GPa on the basis of powder X-ray diffraction; no structural phase transitions or simple shrinkage of the lattice was observed. This result implies that the increase in Tc against pressure cannot simply be explained from a structural point of view. In other words, a direct relation between superconductivity and crystal structure was not found. On the other hand, the CDW transition became ambiguous at pressures higher than 3.8 GPa, suggesting that the Tc had been suppressed by the CDW transition in a low pressure range. Thus, the findings suggest that for Bi2Rh3Se2, Tc is enhanced through the suppression of CDW transition, which may be reasonable because the CDW-ordered state restrains the charge fluctuation to weaken the electron-phonon coupling and opens the gap to decrease the density of states on the Fermi level. The obtained dome-like Tc-p behavior indicates the possibility of Bi2Rh3Se2 being an exotic superconductor.

Verifying the Japanese version of the Healthy Aging Brain Care Monitor self-report tool for evaluating post-intensive care syndrome.

BACKGROUND: Post-intensive care syndrome (PICS) requires the use of multiple assessment tools because it affects multiple domains: Cognitive, Functional, and Behavioural/Psychological. Therefore, this study translated the self-report (SR) version of the Healthy Aging Brain Care Monitor (HABC-M), spanning multiple domains, into Japanese and analysed its reliability and validity in a post-intensive care setting. METHODS: Patients aged 20 years or older and admitted to the adult intensive care unit from August 2019 to January 2021 were included and surveyed by questionnaire. The 21-item Dementia Assessment Sheet for the Regional Comprehensive Care System was used to validate cognitive and physical aspects, and the Patient Health Questionnaire-9, the Generalized Anxiety Disorder-7, and the Post Traumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders 5th edition were used to validate emotional aspects. Reliability was assessed by Cronbach's alpha, and congruent validity by correlation analysis. Multivariate linear regression models were used to identify potential factors for PICS. RESULTS: A total of 104 patients (mean age: 64 ± 14 years) with 3 median mechanical ventilation days (interquartile range: 2-5) were enrolled. The Cognitive domain of the HABC-M SR was highly correlated with memory and disorientation (r = 0.77 for each), while the Functional domain was highly correlated with Instrumental Activities of Daily Living Scale (r = 0.75-0.79). The Behavioural/Psychological domain highly correlated with the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Post Traumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders 5th edition (r = 0.75-0.76). Multivariate analysis revealed longer ICU stays associated with lower Cognitive and Functional (p = 0.03 for each) domains and longer mechanical ventilation days with a lower Behavioural/Psychological domain (p < 0.01). CONCLUSION: The translated Japanese HABC-M SR showed high validity for assessment of the Cognitive, Functional, and Behavioural/Psychological domains of PICS. Therefore, we recommend that the Japanese version of the HABC-M SR be routinely used in the assessment of PICS.

Superconducting Behavior of BaTi2(Sb1-yBiy)2O under Pressure.

The crystal structure and superconducting properties of a new type of titanium-pnictide superconductor, BaTi2(Sb1-yBiy)2O (y = 0.2, 0.5, and 0.8), are comprehensively investigated over a wide pressure range to elucidate the effect of substituting Bi for Sb on the superconducting behavior. The behavior of superconducting properties under pressure changes drastically with y, as expected from the double-dome Tc-y phase diagram obtained at ambient pressure. In this study, three BaTi2(Sb1-yBiy)2O samples (y = 0.2, 0.5, and 0.8) are considered, which correspond to the first superconducting dome, nonsuperconducting part, and second superconducting dome, respectively, in the Tc-y phase diagram. The crystal of BaTi2(Sb1-yBiy)2O with y = 0.2 shows a clear collapse transition, i.e., a drastic shrinkage of the lattice constant c at ca. 5 GPa. Strictly speaking, the collapsed crystal phase coexists with the noncollapsed phase above 5 GPa. On the other hand, BaTi2(Sb1-yBiy)2O with y = 0.8 shows a continuous change in the crystal lattice with pressure, i.e., no collapse transitions. The pressure dependence of Tc for BaTi2(Sb1-yBiy)2O with y = 0.2 shows a drastic increase in Tc at approximately 5 GPa, where the collapse transition occurs, indicating a clear pressure-induced superconducting phase transition related to the collapse transition. The value of Tc for BaTi2(Sb1-yBiy)2O with y = 0.8 increases slightly up to ∼2 GPa and is almost constant at 2-13 GPa. It is found that the superconducting behavior under pressure can be unambiguously classified by y based on the double-dome Tc-y phase diagram, indicative of distinguishable superconducting features at different y values. In this study, we comprehensively discuss the superconducting properties of the exotic material, BaTi2(Sb1-yBiy)2O, with a double-dome Tc-y phase diagram.

Pressure dependence of superconductivity in alkali-Bi compounds KBi2 and RbBi2.

The structural and superconducting properties of alkali-Bi-based compounds, KBi2 and RbBi2, were investigated over a wide pressure range for the first time. The samples of KBi2 and RbBi2 were prepared using a liquid ammonia (NH3) technique, and demonstrated superconductivity with superconducting transition temperatures, Tc, of 3.50 and 4.21 K at ambient pressure, respectively. The onset superconducting transition temperature, Tconset, of KBi2 decreased slightly; however, it suddenly jumped at 2 GPa and increased gradually with pressure, indicating the presence of two superconducting phases in the low-pressure range. The pressure-dependent X-ray diffraction patterns indicate that the KBi2 sample decomposed into KBi and Bi at pressures higher than 2.5 GPa. Moreover, a discontinuous change in Tconset was observed for KBi2 at 9 GPa, which reflects the decomposition of KBi2 into KBi and Bi. By contrast, the value of Tconset of RbBi2 was almost constant over a pressure range of 0-8 GPa. Thus, the superconducting properties and stability of alkali-Bi-based compounds against pressure were comprehensively explored in this study. In addition, the superconducting Cooper pair symmetry was investigated from the magnetic field dependence of Tc of KBi2 at 0.790 and 2.32 GPa, and of RbBi2 at 1.17 GPa, indicating the exact deviation from the simple s-wave paring model, which may be due to the complex electronic structure of Bi. The results elucidated the exotic superconducting properties of KBi2 and RbBi2 based on the pressure and magnetic field dependence of Tc and verified the chemical stability of KBi2 under pressure.

Superconducting properties of BaBi3 at ambient and high pressures.

Herein, we report the preparation and characterization of BaBi3 clarified by DC magnetic susceptibility, powder X-ray diffraction (XRD), and electrical transport. The superconducting properties of BaBi3 were elucidated through the magnetic and electrical transport properties in a wide pressure range. The superconducting transition temperature, Tc, showed a slight decrease (or almost constant Tc) against pressure up to 17.2 GPa. The values of the upper critical field, Hc2, at 0 K, were determined to be 1.27 T at 0 GPa and 3.11 T at 2.30 GPa, using the formula, because p-wave pairing appeared to occur for this material at both pressures, indicating the unconventionality of superconductivity. This result appears to be consistent with the topological non-trivial nature of superconductivity predicted theoretically. The pressure-dependent XRD patterns measured at 0-20.1 GPa indicated no structural phase transitions up to 20.1 GPa, i.e., the structural phase transitions from the α phase to the ß or γ phase which are induced by an application of pressure were not observed, contrary to the previous report, demonstrating that the α phase is maintained over the entire pressure range. Admittedly, the lattice constants and the volume of the unit cell, V, steadily decrease with increasing pressure up to 20.1 GPa. In this study, the plots of Tcversus p and V versus p of BaBi3 are depicted over a wide pressure range for the first time.

Superconductivity of topological insulator Sb2Te3-ySeyunder pressure.

The crystal structures of Sb2Te3-ySey(y= 0.6 andy= 1.2) at 0-24 GPa were investigated by synchrotron x-ray diffraction. The stoichiometry of Sb2Te3-ySeyused in this study was determined to be Sb2Te2.19(9)Se0.7(2)fory= 0.6 and Sb2Te1.7(1)Se1.3(3)fory= 1.2, on the basis of energy-dispersive x-ray spectroscopy. The sample of Sb2Te2.19(9)Se0.7(2)showed a structural phase transition from a rhombohedral structure (space group No. 166,R3¯m) (phase I) to a monoclinic structure (space group No. 12,C2/m) (phase II), with increasing pressure up to ∼9 GPa. A new structural phase (phase II') emerged at 17.7 GPa, a monoclinic structure with the space groupC2/c(No. 15). Finally, a 9/10-fold monoclinic structure (space group No. 12,C2/m) (phase III) was observed at 21.8 GPa. In contrast, the sample of Sb2Te1.7(1)Se1.3(3)provided only phase I (space group No. 166,R3¯m) and phase II (space group No. 12,C2/m), showing one structural phase transition from 0-19.5 GPa. These samples were not superconductors at ambient pressure, but superconductivity suddenly appeared with increasing pressure. Superconductivity with superconducting transition temperatures (Tc's) of 2 and 4 K was observed above 6 GPa in phase I of Sb2Te2.19(9)Se0.7(2). In this sample, theTcvalues of 6 and 9 K were observed in phase II and phase II' or III of Sb2Te2.19(9)Se0.7(2), respectively. Superconductivity withTc's of 4 and 5 K suddenly emerged in Sb2Te1.7(1)Se1.3(3)at 13.6 GPa, which corresponds to phase II, and it evolved to 6.0 K under further increased pressure. ATcvalue of 9 K was finally found above 15 GPa. The magnetic field dependence ofTcin phase II of Sb2Te2.19(9)Se0.7(2)and Sb2Te1.7(1)Se1.3(3)followed ap-wave polar model, suggesting topologically nontrivial superconductivity.