Elastoresistivity in the incommensurate charge density wave phase of BaNi₂(As₁₋ₓPₓ)₂

Electronic nematicity, the breaking of the crystal lattice rotational symmetry by the electronic fluid, is a fascinating quantum state of matter. In this work, using electronic transport under strain we investigate the electronic nematicity of BaNi$_2$(As$_{1−x}$P$_x$)$_2$, a candidate system for charge-induced nematicity. We report a large B$_{1g}$ elastoresistance coefficient that is maximized at the tetragonal-to-orthorhombic transition temperature, that slightly precedes the first-order triclinic transition. An hysteretic behavior is observed in the resistance versus strain sweeps and interpreted as the pinning of orthorhombic domains. Remarkably, the elastoresistance only onsets together with a strong enhancement of the incommensurate charge density wave of the material, strongly suggesting that this electronic instability is uniaxial in nature and drive the orthorhombic transition. The absence of sizeable elastoresistance above this electronic phase clearly contrasts dynamic and static electronic nematicity. Finally, the elastoresistance temperature dependence that strongly differs from the Curie-Weiss form of iron-based superconductors reveals major differences for the respective coupling of electronic nematicity to the lattice. Our results uncover an extremely strain-sensitive platform to study electronic anisotropy induced by a charge-density-wave instability

NHS CHECK: protocol for a cohort study investigating the psychosocial impact of the COVID-19 pandemic on healthcare workers

INTRODUCTION: The COVID-19 pandemic has had profound effects on the working lives of healthcare workers (HCWs), but the extent to which their well-being and mental health have been affected remains unclear. This longitudinal cohort study aims to recruit a cohort of National Health Service (NHS) HCWs, conducting surveys at regular intervals to provide evidence about the prevalence of symptoms of mental disorders, and investigate associated factors such as occupational contexts and support interventions available. METHODS AND ANALYSIS: All staff, students and volunteers working in the 18 participating NHS Trusts in England will be sent emails inviting them to complete a survey at baseline, with email invitations for the follow-up surveys sent 6 months and 12 months later. Opening in late April 2020, the baseline survey collects data on demographics, occupational/organisational factors, experiences of COVID-19, validated measures of symptoms of poor mental health (eg, depression, anxiety, post-traumatic stress disorder), and constructs such as resilience and moral injury. These surveys will be complemented by in-depth psychiatric interviews with a sample of HCWs. Qualitative interviews will also be conducted, to gain deeper understanding of the support programmes used or desired by staff, and facilitators and barriers to accessing such programmes. ETHICS AND DISSEMINATION: Ethical approval for the study was granted by the Health Research Authority (reference: 20/HRA/210, IRAS: 282686) and local Trust Research and Development approval. Cohort data are collected via Qualtrics online survey software, pseudonymised and held on secure university servers. Participants are aware that they can withdraw from the study at any time, and there is signposting to support services if participants feel they need it. Only those consenting to be contacted about further research will be invited to participate in further components. Findings will be rapidly shared with NHS Trusts, and via academic publications in due course

Giant phonon anomalies and central peak due to charge density wave formation in YBa2_2Cu3_3O6.6_{6.6}

The electron-phonon interaction is a major factor influencing the competition between collective instabilities in correlated-electron materials, but its role in driving high-temperature superconductivity in the cuprates remains poorly understood. We have used high-resolution inelastic x-ray scattering to monitor low-energy phonons in YBa$_2$Cu$_3$O$_{6.6}$ (superconducting $\bf T_c = 61$ K), which is close to a charge density wave (CDW) instability. Phonons in a narrow range of momentum space around the CDW ordering vector exhibit extremely large superconductivity-induced lineshape renormalizations. These results imply that the electron-phonon interaction has sufficient strength to generate various anomalies in electronic spectra, but does not contribute significantly to Cooper pairing. In addition, a quasi-elastic "central peak" due to CDW nanodomains is observed in a wide temperature range above and below $\bf T_c$, suggesting that the gradual onset of a spatially inhomogeneous CDW domain state with decreasing temperature is a generic feature of the underdoped cuprates

Prevalence of post-traumatic stress disorder and common mental disorders in health-care workers in England during the COVID-19 pandemic: a two-phase cross-sectional study

Background Previous studies on the impact of the COVID-19 pandemic on the mental health of health-care workers have relied on self-reported screening measures to estimate the point prevalence of common mental disorders. Screening measures, which are designed to be sensitive, have low positive predictive value and often overestimate prevalence. We aimed to estimate prevalence of common mental disorders and post-traumatic stress disorder (PTSD) among health-care workers in England using diagnostic interviews. Methods We did a two-phase, cross-sectional study comprising diagnostic interviews within a larger multisite longitudinal cohort of health-care workers (National Health Service [NHS] CHECK; n=23 462) during the COVID-19 pandemic. In the first phase, health-care workers across 18 NHS England Trusts were recruited. Baseline assessments were done using online surveys between April 24, 2020, and Jan 15, 2021. In the second phase, we selected a proportion of participants who had responded to the surveys and conducted diagnostic interviews to establish the prevalence of mental disorders. The recruitment period for the diagnostic interviews was between March 1, 2021 and Aug 27, 2021. Participants were screened with the 12-item General Health Questionnaire (GHQ-12) and assessed with the Clinical Interview Schedule-Revised (CIS-R) for common mental disorders or were screened with the 6-item Post-Traumatic Stress Disorder Checklist (PCL-6) and assessed with the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) for PTSD. Findings The screening sample contained 23 462 participants: 2079 participants were excluded due to missing values on the GHQ-12 and 11 147 participants due to missing values on the PCL-6. 243 individuals participated in diagnostic interviews for common mental disorders (CIS-R; mean age 42 years [range 21–70]; 185 [76%] women and 58 [24%] men) and 94 individuals participated in diagnostic interviews for PTSD (CAPS-5; mean age 44 years [23–62]; 79 [84%] women and 15 [16%] men). 202 (83%) of 243 individuals in the common mental disorders sample and 83 (88%) of 94 individuals in the PTSD sample were White. GHQ-12 screening caseness for common mental disorders was 52·8% (95% CI 51·7–53·8). Using CIS-R diagnostic interviews, the estimated population prevalence of generalised anxiety disorder was 14·3% (10·4–19·2), population prevalence of depression was 13·7% (10·1–18·3), and combined population prevalence of generalised anxiety disorder and depression was 21·5% (16·9–26·8). PCL-6 screening caseness for PTSD was 25·4% (24·3–26·5). Using CAPS-5 diagnostic interviews, the estimated population prevalence of PTSD was 7·9% (4·0–15·1). Interpretation The prevalence estimates of common mental disorders and PTSD in health-care workers were considerably lower when assessed using diagnostic interviews compared with screening tools. 21·5% of health-care workers met the threshold for diagnosable mental disorders, and thus might benefit from clinical intervention

Chemokine CXCL-1 expression in the subretinal fluid during rhegmatogenous retinal detachment

Purpose: To investigate the expression of chemokine CXCL-1 in the subretinal fluid (SRF) during rhegmatogenous retinal detachment (RRD) and identify potential correlations with number of quadrants involved and duration of the detachment. Methods and Results: Inclusion criteria were patients aged 18 years or older and primary RRD possibly complicated by proliferative vitreoretinopathy (PVR). CXCL-1 levels were measured in 36 SRF samples from 36 RRD patients. Mean CXCL-1 levels (102±37pg/mL) were significantly higher (p=0.050) compared to controls. CXCL-1 levels correlated significantly with age (p=0.001) and RRD duration (p=0.002). Maximum CXCL-1 levels coincided with total RRD, 29- to 60-day duration and PVR grade C. Conclusions: The findings of this study may contribute to increased understanding regarding the role of CXCL-1 during the onset and progression of the wound healing process in the context of RRD and PVR. © 2014 Informa Healthcare USA, Inc

Chemokine CXCL-1 Expression in the Subretinal Fluid during Rhegmatogenous Retinal Detachment

Purpose: To investigate the expression of chemokine CXCL-1 in the subretinal fluid (SRF) during rhegmatogenous retinal detachment (RRD) and identify potential correlations with number of quadrants involved and duration of the detachment. Methods and Results: Inclusion criteria were patients aged 18 years or older and primary RRD possibly complicated by proliferative vitreoretinopathy (PVR). CXCL-1 levels were measured in 36 SRF samples from 36 RRD patients. Mean CXCL-1 levels (102 +/- 37 pg/mL) were significantly higher (p = 0.050) compared to controls. CXCL-1 levels correlated significantly with age (p = 0.001) and RRD duration (p = 0.002). Maximum CXCL-1 levels coincided with total RRD, 29- to 60-day duration and PVR grade C. Conclusions: The findings of this study may contribute to increased understanding regarding the role of CXCL-1 during the onset and progression of the wound healing process in the context of RRD and PVR

Chemokine CXCL-1: Activity in the vitreous during proliferative vitreoretinopathy

The aim of this study was to investigate CXCL-1 chemokine levels in the vitreous during rhegmatogenous retinal detachment (RRD) with and without proliferative vitreoretinopathy (PVR) and identify possible correlations with clinical parameters (extent and duration or RRD and PVR grade). Vitreous samples from patients with primary RRD with or without PVR were collected and assayed using a double antibody enzyme-linked immunosorbent assay (ELISA). Eleven vitreous samples from organ donors were employed as a control group. CXCL-1 levels were measured in 35 vitreous samples from 35 RRD patients. Mean CXCL-1 levels (64·82±6·47 pg/ml) were significantly higher (P = 0·048) compared to controls. There was a significant positive correlation between CXCL-1 levels and the extent of the detachment (r=0·794, P = 0·006). Peak CXCL-1 levels coincided with 3+ quadrant RRD, an interim of 29-60 days' duration and PVR grade B. Increased CXCL-1 levels may be indicative of mild inflammation in the detached retina and the adjacent vitreous. The results of the present study may provide novel insight into the complex interactions taking place during the early and late stages of RRD complicated by PVR. © 2015 British Society for Immunology

Comparison of Chemokine CXCL-1 and Interleukin-6 Concentrations in the Subretinal Fluid and Vitreous in Rhegmatogenous Retinal Detachment

Purpose: Comparison of IL-6 and CXCL-1 concentrations and CXCL-1/IL-6 ratio correlations with clinical parameters (RRD extent, duration, and proliferative vitreoretinopathy–PVR-grade) between subretinal fluid (SRF) and vitreous during rhegmatogenous retinal detachment (RRD) complicated with PVR. Methods: A total of 71 eyes of 71 patients with primary RRD possibly complicated with PVR were included; 36 eyes treated with scleral buckling and 35 eyes with pars-plana vitrectomy. Enzyme-Linked Immuno-sorbent Assay was employed for CXCL-1/IL-6 measurement (ng/ml). Results: Correlation analysis between mean CXCL-1/IL-6 ratio and clinical parameters revealed non-significant results. CXCL-1/IL-6 ratio was significantly elevated in phakic eye vitreous. Optimum circumstances for elevated chemokine levels during RRD were considerable extent (2-3-quadrant) and duration (29-60-day) complicated with PVR C. Conclusions: SRF appears to be characterized by greater chemokine concentrations while vitreous retains several structural characteristics that may assist in investigating inflammation and improving understanding of underlying pathophysiological mechanisms during RRD complicated with PVR. © 2019 Taylor & Francis Group, LLC

Elastoresistivity in the incommensurate charge density wave phase of BaNi2_{\textrm{2}}(As1-x_{\textrm{1-x}}Px_{\textrm{x}})2_{\textrm{2}}

Electronic nematicity, the breaking of the crystal lattice rotational symmetry by the electronic fluid, is a fascinating quantum state of matter. Recently, BaNi$_2$As$_2$ has emerged as a promising candidate for a novel type of nematicity triggered by charge fluctuations. In this work, we scrutinize the electronic nematicity of BaNi$_2$(As$_{1-x}$P$_x$)$_2$ with $0 \leq x \leq 0.10$ using electronic transport measurements under strain. We report a large $B_{1g}$ elastoresistance coefficient that is maximized at a temperature slightly higher than the first-order triclinic transition, and that corresponds to the recently discovered tetragonal-to-orthorhombic transition. The reported elastoresistance does not follow the typical Curie-Weiss form observed in iron-based superconductors but has a much sharper temperature dependence with a finite elastoresistance onsetting only together with a strong enhancement of the incommensurate charge density wave of the material. Consequently, the $B_{1g}$ elastoresistance and the associated orthorhombic distortion appears here as a property of this incommensurate charge density wave. Finally, we report and track the hysteretic behavior seen in the resistance versus strain sweeps and interpret its origin as the pinning of orthorhombic domains. Our results revise the understanding of the interplay between nematicity, charge density waves and structural distortions in this material.Comment: 10 pages, 5 figures. Supplementary materials available on reques

Lattice dynamics across the magnetic transition in (Mn,Fe)1.95(P,Si)\mathrm{(Mn,Fe)_{1.95}(P,Si})

The lattice dynamics in MnFe$_{0.95}$Si$_{0.50}$P$_{0.50}$ were investigated experimentally using $^{57}$Fe nuclear inelastic scattering and inelastic x-ray scattering across the first-order magnetic transition which occurs close to room temperature. The lattice dynamics characterization was supported by a macroscopic magnetic characterization, an x-ray diffraction study, and a hyperfine interactions characterization using Mössbauer spectroscopy. The Fe specific and the x-ray generalized density of phonon states were obtained both in the ferromagnetic and in the paramagnetic state. A prominent shift, 2 meV at 20m eV, in the x-ray generalized density of phonon states across the first-order magnetic transition, that involves vibrations with essentially Fe character, is revealed corroborated by a change in the local environment quantified in the isomer shift and the quadrupole splitting. Above 35 meV the vibrational modes are practically insensitive to the magnetic transition. The entropy change induced by a 1T magnetic field across the magnetic transition, $∼10J/K/kg$, is only a fraction of the Fe vibrational entropy change, $62(21)J/K/kg$