Low Temperature Dynamic Polaron Liquid in a Manganite Exhibiting Colossal Magnetoresistance.

Polarons-fermionic charge carriers bearing a strong companion lattice deformation-exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in insulators, how they evolve in transitions to metallic and superconducting states in quantum materials remains an open question. Here, we use resonant inelastic x-ray scattering to track the electron-lattice coupling in the colossal magneto-resistive bi-layer manganite La_{1.2}Sr_{1.8}Mn_{2}O_{7} across its metal-to-insulator transition. The response in the insulating high-temperature state features harmonic emissions of a dispersionless oxygen phonon at small energy transfer. Upon cooling into the metallic state, we observe a drastic redistribution of spectral weight from the region of these harmonic emissions to a broad high energy continuum. In concert with theoretical calculations, we show that this evolution implies a shift in electron-lattice coupling from static to dynamic lattice distortions that leads to a distinct polaronic ground state in the low temperature metallic phase-a dynamic polaron liquid.

Magnetic excitations in infinite-layer nickelates.

The discovery of superconductivity in infinite-layer nickelates brings us tantalizingly close to a material class that mirrors the cuprate superconductors. We measured the magnetic excitations in these nickelates using resonant inelastic x-ray scattering at the Ni L 3-edge. Undoped NdNiO2 possesses a branch of dispersive excitations with a bandwidth of approximately 200 milli-electron volts, which is reminiscent of the spin wave of strongly coupled, antiferromagnetically aligned spins on a square lattice. The substantial damping of these modes indicates the importance of coupling to rare-earth itinerant electrons. Upon doping, the spectral weight and energy decrease slightly, whereas the modes become overdamped. Our results highlight the role of Mottness in infinite-layer nickelates.

Guidelines for clinical trials of frontal fibrosing alopecia: consensus recommendations from the International FFA Cooperative Group (IFFACG).

BACKGROUND: Frontal fibrosing alopecia (FFA) has become one of the most common causes of cicatricial alopecia worldwide. However, there is a lack of clear aetiology and robust clinical trial evidence for the efficacy and safety of agents currently used for treatment. OBJECTIVES: To enable data to be collected worldwide on FFA using common criteria and assessment methods. METHODS: A multicentre, international group of experts in hair loss was convened by email to create consensus recommendations for clinical trials. Consensus was defined at > 90% agreement on each recommended part of these guidelines. RESULTS: Standardized diagnostic criteria, severity rating, staging, and investigator and patient assessment of scalp hair loss and other clinical features of FFA were created. CONCLUSIONS: These guidelines should allow the collection of reliable aggregate data on FFA and advance efforts in both clinical and basic research to close knowledge gaps in this condition.

Time-resolved RIXS experiment with pulse-by-pulse parallel readout data collection using X-ray free electron laser.

Time-resolved resonant inelastic X-ray scattering (RIXS) is one of the developing techniques enabled by the advent of X-ray free electron laser (FEL). It is important to evaluate how the FEL jitter, which is inherent in the self-amplified spontaneous emission process, influences the RIXS measurement. Here, we use a microchannel plate (MCP) based Timepix soft X-ray detector to conduct a time-resolved RIXS measurement at the Ti L3-edge on a charge-density-wave material TiSe2. The fast parallel Timepix readout and single photon sensitivity enable pulse-by-pulse data acquisition and analysis. Due to the FEL jitter, low detection efficiency of spectrometer, and low quantum yield of RIXS process, we find that less than 2% of the X-ray FEL pulses produce signals, preventing acquiring sufficient data statistics while maintaining temporal and energy resolution in this measurement. These limitations can be mitigated by using future X-ray FELs with high repetition rates, approaching MHz such as the European XFEL in Germany and LCLS-II in the USA, as well as by utilizing advanced detectors, such as the prototype used in this study.

Publisher Correction: Electronic structure of the parent compound of superconducting infinite-layer nickelates.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Electronic structure of the parent compound of superconducting infinite-layer nickelates.

The search continues for nickel oxide-based materials with electronic properties similar to cuprate high-temperature superconductors1-10. The recent discovery of superconductivity in the doped infinite-layer nickelate NdNiO2 (refs. 11,12) has strengthened these efforts. Here, we use X-ray spectroscopy and density functional theory to show that the electronic structure of LaNiO2 and NdNiO2, while similar to the cuprates, includes significant distinctions. Unlike cuprates, the rare-earth spacer layer in the infinite-layer nickelate supports a weakly interacting three-dimensional 5d metallic state, which hybridizes with a quasi-two-dimensional, strongly correlated state with [Formula: see text] symmetry in the NiO2 layers. Thus, the infinite-layer nickelate can be regarded as a sibling of the rare-earth intermetallics13-15, which are well known for heavy fermion behaviour, where the NiO2 correlated layers play an analogous role to the 4f states in rare-earth heavy fermion compounds. This Kondo- or Anderson-lattice-like 'oxide-intermetallic' replaces the Mott insulator as the reference state from which superconductivity emerges upon doping.

A high-power, high-repetition-rate THz source for pump-probe experiments at Linac Coherent Light Source II.

Experiments using a THz pump and an X-ray probe at an X-ray free-electron laser (XFEL) facility like the Linac Coherent Light Source II (LCLS II) require frequency-tunable (3 to 20 THz), narrow bandwidth (∼10%), carrier-envelope-phase-stable THz pulses that produce high fields (>1 MV cm-1) at the repetition rate of the X-rays and are well synchronized with them. In this paper, a two-bunch scheme to generate THz radiation at LCLS II is studied: the first bunch produces THz radiation in an electromagnet wiggler immediately following the LCLS II undulator that produces X-rays from the second bunch. The initial time delay between the two bunches is optimized to compensate for the path difference in THz transport. The two-bunch beam dynamics, the THz wiggler and radiation are described, as well as the transport system bringing the THz pulses from the wiggler to the experimental hall.

In-Grove Spatiotemporal Spread of Citrus Huanglongbing and Its Psyllid Vector in Relation to Weather.

Reports of spatial patterns of 'Candidatus Liberibacter asiaticus'-infected asymptomatic citrus trees and 'Ca. L. asiaticus'-positive Asian citrus psyllids (ACP) are rare, as are published relationships between huanglongbing (HLB), ACP, and weather. Here, spatial patterns of 'Ca. L. asiaticus'-positive asymptomatic and symptomatic trees were determined every half year in a small grove over 2.5 years, and of HLB-symptomatic trees and ('Ca. L. asiaticus'-positive) ACP populations every month in two commercial groves for 1 year. Spread of symptomatic trees followed that of asymptomatic 'Ca. L. asiaticus'-positive trees with <6 months' delay. 'Ca. L. asiaticus'-positive asymptomatic and symptomatic fronts moved at 2.5 to 3.6 m month-1. No spatial relationship was detected between ACP populations and HLB-infected trees. HLB incidence and 'Ca. L. asiaticus'-positive ACP dynamics were tentatively positively correlated with monthly rainfall data and, to a lesser extent, with average minimum temperature.

Three-dimensional collective charge excitations in electron-doped copper oxide superconductors.

High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides5-7 reveals their charge origin, that is, without mixing with magnetic components5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems8-12 and argued to play a substantial part in mediating high-temperature superconductivity10-12.

Incidence, risk factors, and fracture healing of atypical femoral fractures: a multicenter case-control study.

The incidence of atypical femoral fractures (AFFs) was 2.95% among 6644 hip and femoral fractures. Independent risk factors included the use of bisphosphonates (BPs), osteopenia or osteoporosis, rheumatoid arthritis, increased femoral curvatures, and thicker femoral cortices. Patients with AFFs and BP treatment were more likely to have problematic healing than those with typical femoral fractures (TFFs) and no BP treatment. INTRODUCTION: To determine the incidence and risk factors of atypical femoral fractures (AFFs), we performed a multicenter case-control study. We also investigated the effects of bisphosphonates (BPs) on AFF healing. METHODS: We retrospectively reviewed the medical records and radiographs of 6644 hip and femoral fractures of patients from eight tertiary referral hospitals. All the radiographs were reviewed to distinguish AFFs from TFFs. Univariate and multivariate logistic regression analyses were performed to identify risk factors, and interaction analyses were used to investigate the effects of BPs on fracture healing. RESULTS: The incidence of AFFs among 6644 hip and femoral fractures was 2.95% (90 subtrochanter and 106 femoral shaft fractures). All patients were females with a mean age of 72 years, and 75.5% were exposed to BPs for an average duration of 5.2 years (range, 1-17 years). The use of BPs was significantly associated with AFFs (p < 0.001, odds ratio = 25.65; 95% confidence interval = 10.74-61.28). Other independent risk factors for AFFs included osteopenia or osteoporosis, rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex at the shaft level. Interaction analyses showed that patients with AFFs using BPs had a significantly higher risk of problematic fracture healing than those with TFFs and no BP treatment. CONCLUSIONS: The incidence of AFFs among 6644 hip and femoral fractures was 2.95%. Osteopenia or osteoporosis, use of BPs, rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex were independent risk factors for the development of AFFs. Patients with AFFs and BP treatment were more likely to have problematic fracture healing than those with TFFs and no BP treatment.

Regional Spatial-Temporal Spread of Citrus Huanglongbing Is Affected by Rain in Florida.

Citrus huanglongbing (HLB), associated with 'Candidatus Liberibacter asiaticus' (Las), disseminated by Asian citrus psyllid (ACP), has devastated citrus in Florida since 2005. Data on HLB occurrence were stored in databases (2005 to 2012). Cumulative HLB-positive citrus blocks were subjected to kernel density analysis and kriging. Relative disease incidence per county was calculated by dividing HLB numbers by relative tree numbers and maximum incidence. Spatiotemporal HLB distributions were correlated with weather. Relative HLB incidence correlated positively with rainfall. The focus expansion rate was 1626 m month-1, similar to that in Brazil. Relative HLB incidence in counties with primarily large groves increased at a lower rate (0.24 year-1) than in counties with smaller groves in hotspot areas (0.67 year-1), confirming reports that large-scale HLB management may slow epidemic progress.

A novel, cell-permeable, collagen-based membrane promotes fibroblast migration.

BACKGROUND AND OBJECTIVE: Growth factors are frequently incorporated into scaffolds to promote periodontal regeneration but many currently used scaffolds do not encourage cell migration towards the dentogingival junction. We examined the proliferation and migration of human gingival fibroblasts in a novel, physically robust, collagen-Vicryl™ membrane loaded with fibronectin (FN) and/or insulin-like growth factor (IGF-I). Biocompatibility of the membranes was evaluated in rat dorsal skin. MATERIAL AND METHODS: Chemotaxis was examined in Boyden chambers and cell migration by confocal imaging of membranes, which were fabricated from rat tail type I collagen with embedded Vicryl knitted mesh, IGF-I (50, 100 ng/mL) and FN (10 µg/mL). Membranes (Vicryl alone, collagen+Vicryl, collagen+Vicryl+IGF-I, collagen+Vicryl+FN') were implanted subcutaneously in 8 rats and were evaluated by histomorphometry after 7 and 14 days. RESULTS: IGF-I (50 or 100 ng/mL) promoted chemotaxis compared with vehicle controls (P = .02, P = .001, respectively). IGF-I did not affect cell proliferation. Incorporation of FN retarded time-dependent release of IGF-I from collagen gels. Three dimensional confocal microscopy imaging of cell migration through collagen+Vicryl membranes showed enhanced migration in the IGF+FN group compared to all other groups at 8, 10 and 14 days (P < .05). In a rat skin model, implanted membranes were surrounded by thin collagen capsules and mild inflammatory infiltrates. CONCLUSION: Incorporation of FN into IGF-I-loaded collagen+Vicryl membranes reduced IGF release from collagen and increased the migration of human gingival fibroblasts. The new membrane may promote healing and reformation of the dentogingival junction.

Association between ambient air pollution and pregnancy rate in women who underwent IVF.

STUDY QUESTION: Are the concentrations of five criteria air pollutants associated with probabilities of biochemical pregnancy loss and intrauterine pregnancy in women? SUMMARY ANSWER: Increased concentrations of ambient particulate matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO) during controlled ovarian stimulation (COS) and after embryo transfer were associated with a decreased probability of intrauterine pregnancy. WHAT IS KNOWN ALREADY: Exposure to high ambient air pollution was suggested to be associated with low fertility and high early pregnancy loss in women. STUDY DESIGN, SIZE, DURATION: Using a retrospective cohort study design, we analysed 6621 cycles of 4581 patients who underwent one or more fresh IVF cycles at a fertility centre from January 2006 to December 2014, and lived in Seoul at the time of IVF treatment. PARTICIPANTS/MATERIALS, SETTING, METHODS: To estimate patients' individual exposure to air pollution, we computed averages of hourly concentrations of five air pollutants including PM10, NO2, CO, sulphur dioxide (SO2) and ozone (O3) measured at 40 regulatory monitoring sites in Seoul for each of the four exposure periods: period 1 (start of COS to oocyte retrieval), period 2 (oocyte retrieval to embryo transfer), period 3 (embryo transfer to hCG test), and period 4 (start of COS to hCG test). Hazard ratios (HRs) from the time-varying Cox-proportional hazards model were used to estimate probabilities of biochemical pregnancy loss and intrauterine pregnancy for an interquartile range (IQR) increase in each air pollutant concentration during each period, after adjusting for individual characteristics. We tested the robustness of the result using generalised linear mixed model, accounting for within-woman correlation. MAIN RESULTS AND THE ROLE OF CHANCE: Mean age of the women was 35 years. Average BMI was 20.9 kg/m2 and the study population underwent 1.4 IVF cycles on average. Cumulative pregnancy rate in multiple IVF cycles was 51.3% per person. Survival analysis showed that air pollution during periods 1 and 3 was generally associated with IVF outcomes. Increased NO2 (adjusted HR = 0.93, 95% CI: 0.87, 0.99) and CO (0.94, 95% CI: 0.89, 1.00) during period 1 were associated with decreased probability of intrauterine pregnancy. PM10 (0.92, 95% CI: 0.85, 0.99), NO2 (0.93, 95% CI = 0.86, 1.00) and CO (0.93, 95% CI: 0.87, 1.00) levels during period 3 were also inversely associated with intrauterine pregnancy. Both PM10 (1.17, 95% CI: 1.04 1.33) and NO2 (1.18, 95% CI: 1.03, 1.34) during period 3 showed positive associations with biochemical pregnancy loss. LIMITATIONS, REASONS FOR CAUTION: The district-specific ambient air pollution treated as an individual exposure may not represent the actual level of each woman's exposure to air pollution. Smoking, working status, parity or gravidity of women, and semen analysis data were not included in the analysis. WIDER IMPLICATIONS OF THE FINDINGS: This study provided evidence of an association between increased ambient concentrations of PM10, NO2 and CO and reduced probabilities for achieving intrauterine pregnancy using multiple IVF cycle data. Specifically, our results indicated that lower intrauterine pregnancy rates in IVF cycles may be linked to ambient air pollution during COS and the post-transfer period. STUDY FUNDING/COMPETING INTEREST(S): This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013 R1A6A3A04059017, 2016 R1D1A1B03933410 and 2018 R1A2B6004608) and the National Cancer Center of Korea (NCC-1810220-01). The authors report no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Increased prevalence of vitamin D deficiency in patients with alopecia areata: a systematic review and meta-analysis.

BACKGROUND: Alopecia areata (AA) is a hair follicle-specific autoimmune disorder. Vitamin D deficiency has been associated with various autoimmune disorders for its immunomodulatory effects. However, in previous studies, there had been inconsistent association found between AA and vitamin D deficiency. OBJECTIVE: To demonstrate the differences of the mean serum 25-hydroxyvitamin D level and prevalence of vitamin D deficiency between AA patients and non-AA population. METHODS: A systematic review and meta-analysis of observational studies on AA and serum vitamin D levels and/or prevalence of vitamin D deficiency was performed searching MEDLINE, Cochrane, Web of Science and Google Scholar databases. RESULTS: In all, 14 studies including a total of 1255 AA subjects and 784 non-AA control were analysed. The mean serum 25-hydroxyvitamin D level was significantly lower in AA subjects (-8.52 ng/dL; 95% confidential interval; -5.50 to -11.53). The AA subjects had higher odds of vitamin D deficiency (odds ratio of 3.89; 2.02 to 7.49, mean prevalence of 73.8%; 59.1 to 84.6%). However, it was difficult to find clear correlation between serum 25-hydroxyvitamin D level and extent of hair loss in AA subjects. CONCLUSION: The AA subjects had lower serum 25-hydroxyvitamin D level, and vitamin D deficiency was highly prevalent compared to non-AA controls. Hence, vitamin D deficiency should be assessed in AA patients. Furthermore, nutritional supplementation of vitamin D or topical vitamin D analogues can be considered for AA patients with vitamin D deficiency. The limitation of this study is the highly heterogeneity of the included studies.

Novel proteins that regulate cell extension formation in fibroblasts.

Cell extensions are critical structures that enable matrix remodeling in wound healing and cancer invasion but the regulation of their formation is not well-defined. We searched for new proteins that mediated cell extension formation over collagen by tandem mass tagged mass spectrometry analysis of purified extensions in 3T3 fibroblasts. Unexpectedly, importin-5, ENH isoform 1b (PDLIM5) and 26 S protease regulatory subunit 6B (PSMC4) were more abundant (> 10-fold) in membrane-penetrating cell extensions than cell bodies, which was confirmed by immunostaining and immunoblotting and also observed in human gingival fibroblasts. After siRNA knockdown of these proteins and plating cells on grid-supported floating collagen gels for 6 h, formation of cell extensions and collagen remodeling were examined. Knockdown of importin-5 reduced collagen compaction (1.9-fold), pericellular collagen degradation (~ 1.8-fold) and number of cell extensions (~ 69%). Knockdown of PSMC4 reduced collagen compaction (~ 1.5-fold), pericellular collagen degradation (~ 1.7-fold) and number of cell extensions (~ 42%). Knockdown of PDLIM5 reduced collagen compaction (~ 1.6-fold) and number of cell extensions (~ 21%). Inhibition of the TGF-ß RI kinase, Smad3 or ROCK-II signaling pathways reduced the abundance of PDLIM5 in cell extensions but PSMC4 and importin-5 were reduced only by Smad3 or ROCK-II inhibitors. We conclude that these novel proteins are required for cell extension formation and their recruitment into extensions involves the Smad3 and ROCK signaling pathways.

Introduction to CAUSES: Description of Weather and Climate Models and Their Near-Surface Temperature Errors in 5 day Hindcasts Near the Southern Great Plains.

We introduce the Clouds Above the United States and Errors at the Surface (CAUSES) project with its aim of better understanding the physical processes leading to warm screen temperature biases over the American Midwest in many numerical models. In this first of four companion papers, 11 different models, from nine institutes, perform a series of 5 day hindcasts, each initialized from reanalyses. After describing the common experimental protocol and detailing each model configuration, a gridded temperature data set is derived from observations and used to show that all the models have a warm bias over parts of the Midwest. Additionally, a strong diurnal cycle in the screen temperature bias is found in most models. In some models the bias is largest around midday, while in others it is largest during the night. At the Department of Energy Atmospheric Radiation Measurement Southern Great Plains (SGP) site, the model biases are shown to extend several kilometers into the atmosphere. Finally, to provide context for the companion papers, in which observations from the SGP site are used to evaluate the different processes contributing to errors there, it is shown that there are numerous locations across the Midwest where the diurnal cycle of the error is highly correlated with the diurnal cycle of the error at SGP. This suggests that conclusions drawn from detailed evaluation of models using instruments located at SGP will be representative of errors that are prevalent over a larger spatial scale.