High-temperature superconductivity appears as a consequence of doping charge carriers into an undoped parent compound exhibiting antiferromagnetic order; therefore, ground-state properties of the ...parent compound are highly relevant to the superconducting state. On the basis of this logic, spin fluctuations have been considered as the origin of pairing of the superconducting electrons in the cuprates. As possible pairing mechanisms, there is growing interest in unconventional spin fluctuations or advanced orbital fluctuations owing to the characteristic multi-orbital states in iron pnictides. Here, we report the discovery of an antiferromagnetic phase as well as a unique structural transition in electron-overdoped LaFeAsO1-x Hx (x thick ~ 0.5), whereby a second parent phase is uncovered, albeit heavily doped. The unprecedented two-dome superconducting phases observed in this material can be interpreted as a consequence of the carrier doping starting from the original x thick ~ 0 and additional x thick ~ 0.5 parent phases towards the intermediate region. The bipartite parent phases with distinct physical properties in the second magnetic phase provide us with an interesting example to illustrate the intimate interplay between the magnetic interaction, structural change and orbital degree of freedom in iron pnictide superconductors.
Cd2Os2O7 shows a peculiar metal-insulator transition at 227 K with magnetic ordering in a frustrated pyrochlore lattice, but its magnetic structure in the ordered state and the transition origin are ...yet uncovered. We observed a commensurate magnetic peak by resonant x-ray scattering in a high-quality single crystal. X-ray diffraction and Raman scattering experiments confirmed that the transition is not accompanied with any spatial symmetry breaking. We propose a noncollinear all-in-all-out spin arrangement on the tetrahedral network made of Os atoms. Based on this we suggest that the transition is not caused by the Slater mechanism as believed earlier but by an alternative mechanism related to the formation of the specific tetrahedral magnetic order on the pyrochlore lattice in the presence of strong spin-orbit interactions.
Purpose We evaluated which variables impact fragmentation and clearance of lower pole calculi after shock wave lithotripsy. Materials and Methods We prospectively evaluated patients undergoing shock ...wave lithotripsy for a solitary 5 to 20 mm lower pole kidney stone between June 2012 and August 2014. Patient body mass index and abdominal waist circumference were recorded. One radiologist blinded to shock wave lithotripsy outcomes measured stone size, area and density, stone-to-skin distance, infundibular length, width and height, and infundibulopelvic angle based on baseline noncontrast computerized tomography. Fragmentation, success (defined as residual fragments less than 4 mm in asymptomatic patients) and the stone-free rate were evaluated by noncontrast computerized tomography 12 weeks postoperatively. Univariate and multivariate analysis was performed. Results A total of 100 patients were enrolled in the study. Mean stone size was 9.1 mm. Overall fragmentation, success and stone-free rates were 76%, 54% and 37%, respectively. On logistic regression body mass index (OR 1.27, 95% CI 1.11–1.49, p = 0.004) and stone density (OR 1.0026, 95% CI 1.0008–1.0046, p = 0.005) significantly impacted fragmentation. Stone size (OR 1.24, 95% CI 1.07–1.48, p = 0.039) and stone density (OR 1.0021, 95% CI 1.0007–1.0037, p = 0.012) impacted the success rate while stone size (OR 1.24, 95% CI 1.04–1.50, p = 0.029), stone density (OR 1.0015, 95% CI 1.0001–1.0032, p = 0.046) and infundibular length (OR 1.1035, 95% CI 1.015–1.217, p = 0.015) impacted the stone-free rate. The best outcomes were found in patients with a body mass index of 30 kg/m2 or less, stones 10 mm or less and 900 HU or less, and an infundibular length of 25 mm or less. The coexistence of significant unfavorable variables led to a stone-free rate of less than 20%. Conclusions Obese patients with higher than 10 mm density stones (greater than 900 HU) in the lower pole of the kidney with an infundibular length of greater than 25 mm should be discouraged from undergoing shock wave lithotripsy.
The electronic and magnetic states of β− MnO2 in terms of hydrogen impurities have been investigated by the muon spin rotation technique combined with density-functional theory (DFT) calculations for ...muon as pseudohydrogen. We found that 85% of implanted muons are localized in the oxygen channels of the rutile structure and behave like interstitial protons (Mu+) except those (7.6%) forming a charge-neutral state (Mu0) at 2.3 K, which indicates that interstitial hydrogen acts like a shallow donor within less than 0.1 meV of ionization energy. The residual 15% of muons are attributed to those related to lattice imperfection as Mn vacancies. Detailed analyses combined with the DFT approach suggested that the muon is localized at the center of the oxygen channel due to its large zero-point vibration energy.
We developed a new positron detector system called Kalliope, which is based on multi-pixel avalanch photo-diode (m-APD), application specific integrated circuit (ASIC), field programmable gated array ...(FPGA) and ethernet-based SiTCP data transfer technology. We have manufactured a general-purpose spectrometer for muon spin relaxation (μSR) measurements, employing 40 Kalliope units (1280 channels of scintillators) installed in a 0.4 T longitudinal-field magnet. The spectrometer has been placed at D1 experimental area of J- PARC Muon Science Establishment (MUSE). Since February of 2014, the spectrometer has been used for the user programs of MUSE after a short commissioning period of one week. The data accumulation rate of the new spectrometer is 180 million positron events per hour (after taking the coincidence of two scintillators of telescopes) from a 20×20 mm sample for double-pulsed incoming muons.
Undercooling of various Fe–Cu–(Si) alloys with a small amount of B was examined. The temperature change during the static undercooling experiment was analyzed. The temperature curve showed ...significant undercooling. The melt was undercooled below the metastable liquid miscibility gap. In these samples, two melts separation was observed. The addition of B was effective for two melts separation. By rapid solidification of ternary Fe–Cu–B alloys, relatively uniform structure composed of iron rich droplets in copper rich matrix or copper rich droplets in iron rich matrix was formed depending on the composition. In the case of a rapidly solidified Fe–Cu–Si–B alloy, the egg-type structure was formed and some of the iron rich phase was amorphous.
The primary purpose of this study is to determine the malignancy rate, histologic grade, and initial stage of surgically treated complex renal cysts classified as Bosniak category III or IV. For ...nonsurgical lesions, a secondary objective was to evaluate lesion progression on follow-up examinations.
We searched our database for cystic lesions classified as Bosniak III or IV category on CT or MRI from January 2008 to April 2016. Surgically resected lesions, per category, were correlated with information on pathologic reports to obtain malignancy rates. For malignant lesions, histologic grade and initial stage were evaluated. Imaging follow-up of at least 2 years was used to evaluate progression of clinically followed lesions.
We included 86 lesions in 85 patients in the final analysis. Of the 60 surgically resected lesions (70%), 46 (77%) were malignant and 14 (23%) were benign. Malignancy rates were 72% for Bosniak category III lesions and 86% for Bosniak category IV lesions. Most malignant cysts were early-stage (pT1) cysts with low histologic grades (89% of Bosniak III lesions and 91% of Bosniak IV lesions). Follow-up studies of the surgically resected lesions did not show local recurrence, metastasis, or lymph node enlargement. Among patients with lesions managed by watchful waiting (n = 26), all lesions remained unchanged in terms of size and complexity after at least 2-years of follow-up.
Although high malignancy rates were observed for both Bosniak category III and IV lesions, our results suggest that such malignant cysts are usually early-stage tumors with a low histologic grade. Lesions that underwent follow-up remained unchanged on control examinations. These findings may indicate low aggressiveness of these lesions, supporting the idea that more conservative approaches may be used.
It is shown in a new class of pyrochlore compound YMn2Zn20-xInx (with x 2.36) that the spin fluctuation rate (v) is proportional to temperature (v ∝ T) below T0 ~10 K where heavy-fermion(HF)-like ...behavior is observed. Such a linear T dependence, commonly found in Y(Sc)Mn2 and LiV2O4, is expected for intersecting quasi-1D Hubbard chains, suggesting that the quasi-1D character of the t2g band associated with the pyrochlore lattice plays an important role in the emergence of the HF-like state, where T0 may correspond to intra-chain antiferromagnetic interaction energy between Mn spins.
We report on a spin-charge fluctuation in the all-in/all-out pyrochlore magnet Cd2 Os2 O7, where the spin fluctuation is driven by the conduction of thermally excited electrons/holes and associated ...fluctuation of Os valence. The fluctuation exhibits an activation energy significantly greater than the spin-charge excitation gap and a peculiar frequency range of 106–1010s−1. These features are attributed to the hopping motion of carriers as small polarons in the insulating phase, where the polaron state is presumably induced by the magnetoelastic coupling via the strong spin-orbit interaction. Such a coupled spin-charge-phonon fluctuation manifests as a part of the metal-insulator transition that is extended over a wide temperature range due to the modest electron correlation comparable with other interactions characteristic for 5d -subshell systems.
Endometriosis is a highly prevalent disease that affects 10%-15% of women of reproductive age worldwide and is mainly associated with chronic pelvic pain and infertility. With the widespread use of ...imaging for the diagnosis and monitoring of endometriosis, combined with the ability of surgery to eradicate the disease and address infertility, there has been a significant increase in recent years in imaging examinations for postoperative evaluation of endometriosis. US and MRI are used not only to help diagnose and map endometriosis but also to evaluate refractory symptoms, residual lesions, and complications at posttreatment assessment. Knowledge of surgical techniques and recognition of expected postoperative imaging findings are crucial to differentiate postoperative changes from residual disease and/or recurrence. The authors discuss imaging aspects of postoperative endometriosis, with an emphasis on the imaging approach, comprehension of surgical techniques, recognition of the expected findings, possible complications, and analysis of residual disease or recurrence.
RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by VanBuren in this issue. The slide presentation from the RSNA Annual Meeting is available for this article.
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