A tunable clamshell cavity for wavelike dark matter searches.

Here, we present a frequency tuning mechanism for microwave cavities designed for axion dark matter searches and show that it provides a range of at least 200 MHz for the fundamental mode TM010 resonant at ∼10 GHz. The apparatus is based on a clamshell cavity, with the two semi-cells held together at a fixed joint while the other side opens to tune the frequency of the resonant modes. Measurements of the cavity frequencies and quality factor were taken at liquid helium temperature as the aperture was increased incrementally to ∼2°. We show that the frequency shift is approximately linear with respect to the angle of aperture with no mode crossings present for an aperture less than 2°. Furthermore, the form factor and quality factor of the TM010 mode remain relatively constant throughout the tuning as predicted by simulation.

Relationship between sex and clinical and imaging features of early axial spondyloarthritis: results from a 48 month follow-up (Italian arm of the SPondyloArthritis Caught Early (SPACE) study).

OBJECTIVES: To assess the association between sex and clinical and disease activity indices, and X-rays and magnetic resonance imaging (MRI) features, in early-stage axial spondyloarthritis (axSpA). METHOD: Baseline data analysis was conducted on the Italian SPACE cohort, including patients with chronic back pain (duration ≥ 3 months and ≤ 2 years; onset < 45 years). Patients underwent MRI and X-rays of the sacroiliac joints (SIJs) to establish the diagnosis of axSpA, according to Assessment of SpondyloArthritis international Society criteria and physician's judgement. Clinical features, disease activity and functional indices, and images were collected at baseline and yearly during 48 months. Spinal and SIJ X-rays and MRI images were scored by two readers following Spondyloarthritis Research Consortium of Canada (SPARCC), modified Stoke Ankylosing Spondylitis Spinal Score, and modified New York criteria. Characteristics of axSpA patients according to sex (male/female) were compared over time using descriptive statistics. RESULTS: Ninety-one patients had axSpA (83.5% non-radiographic; 16.5% radiographic); 47.3% were male. Males were younger, with shorter duration of axial symptoms, and more frequently had HLA-B27 positivity, radiographic sacroiliitis with a bilateral/symmetric pattern, and more signs of spondylitis. Females more frequently showed peripheral/entheseal involvement and the non-radiographic phenotype. Males showed increased pelvic/spinal radiographic progression and more often had active sacroiliitis on MRI. Although the frequency of inflammatory corner lesions did not differ between males and females, localization varied, with more cervical/thoracic MRI-spine lesions in females and more lumbar lesions in males. We observed a significant downward trend of SPARCC SIJ/spine scores in all patients, irrespective of sex. More fat lesions were observed on MRI-spine in females and on MRI-SIJ in males. CONCLUSION: Sex was associated with distinct axSpA features: females showed low-grade radiographic sacroiliitis and spinal progression, and a higher prevalence of cervical and thoracic spine MRI signs.

High quality factor photonic cavity for dark matter axion searches.

Searches for dark matter axions involve the use of microwave resonant cavities operating in a strong magnetic field. Detector sensitivity is directly related to the cavity quality factor, which is limited, until recently, to the use of non-superconducting metals by the presence of the external magnetic field. In this paper, we present a cavity of novel design whose quality factor is not affected by a magnetic field. It is based on a photonic structure by the use of sapphire rods. The quality factor at cryogenic temperature is in excess of 5 × 105 for a selected mode.

SARS-CoV-2 infection in patients with autoimmune rheumatic diseases in northeast Italy: A cross-sectional study on 916 patients.

BACKGROUND: Whether patients with autoimmune rheumatic diseases (ARD) have a higher risk for SARS-CoV-2 infection (COVID-19) and how SARS-CoV-2 pandemic impacts on adherence to therapy has not been fully elucidated. We assessed the rate and clinical presentation of COVID-19, and adherence to therapy in a large cohort of patients with ARD followed-up in a tertiary University-Hospital in Northeast Italy. METHODS: Between April 9th and April 25th, 2020, after SARS-CoV-2 infection peak, a telephone survey investigating the impact of COVID-19 on patients with systemic lupus erythematosus (SLE), systemic sclerosis (SSc), rheumatoid arthritis (RA), ANCA-associated vasculitis (AAV), and idiopathic inflammatory myopathies (IIM) was administered. Demographics, disease activity status, therapy, occupational exposure, and adherence to social distancing advise were also collected. RESULTS: 916 patients (397 SLE, 182 AAV, 176 SSc, 111 RA, 50 IIM) completed the survey. 148 patients developed at least one symptom compatible with COVID-19 (cough 96, sore throat 64, fever 64, arthromyalgias 59, diarrhea 26, conjunctivitis 18, ageusia/hyposmia, 18). Among the 916 patients, 65 (7.1%) underwent SARS-CoV-2 nasopharyngeal swab (18 symptomatic and 47 asymptomatic), 2 (0.21%) tested positive, a proportion similar to that observed in the general population of the Veneto region. No deaths occurred. 31 patients (3.4%) withdrew ≥1 medication, mainly immunosuppressants or biologics. Adoption of social distancing was observed by 860 patients (93.9%), including 335 (36.6%) who adopted it before official lockdown. CONCLUSIONS: COVID-19 incidence seems to be similar in our cohort compared to the general population. Adherence to therapy and to social distancing advise was high.

Axion Search with a Quantum-Limited Ferromagnetic Haloscope.

A ferromagnetic axion haloscope searches for dark matter in the form of axions by exploiting their interaction with electronic spins. It is composed of an axion-to-electromagnetic field transducer coupled to a sensitive rf detector. The former is a photon-magnon hybrid system, and the latter is based on a quantum-limited Josephson parametric amplifier. The hybrid system consists of ten 2.1 mm diameter yttrium iron garnet spheres coupled to a single microwave cavity mode by means of a static magnetic field. Our setup is the most sensitive rf spin magnetometer ever realized. The minimum detectable field is 5.5×10^{-19} T with 9 h integration time, corresponding to a limit on the axion-electron coupling constant g_{aee}≤1.7×10^{-11} at 95% C.L. The scientific run of our haloscope resulted in the best limit on dark matter axions to electron coupling constant in a frequency span of about 120 MHz, corresponding to the axion-mass range 42.4-43.1 µeV. This is also the first apparatus to perform a wide axion-mass scanning by only changing the static magnetic field.

Biomarkers, imaging and disease activity indices in patients with early axial spondyloarthritis: the Italian arm of the SpondyloArthritis-Caught-Early (SPACE) Study.

The study aimed to evaluate biomarkers facilitating early diagnosis of axial spondyloarthritis (axSpA) and correlations between them and disease activity parameters and imaging indexes. Patients with low back pain (LBP) (≥3 months, ≤2 years, onset ≤45 years) participating in the Italian arm of the SpondyloArthritis-Caught-Early SPACE study underwent a physical examination, questionnaires, laboratory tests, X-rays and MRI of the spine and sacroiliac joints (SIJ). An expert rheumatologist formulated axSpA diagnosis in accordance with Assessment of SpondyloArthritis International Society (ASAS) criteria. Disease activity and physical functioning were assessed using imaging, clinical and serological indices. Spine and SIJ MRI and X-rays were scored independently by 2 readers using the SPARCC, mSASSS and NY-criteria. Patients were classified as: subjects with signs of radiographic sacroiliitis (r-axSpA), subjects with signs of sacroiliitis on SIJ-MRI but not on X-rays (nr-axSpA MRI SIJ+) or subjects with no signs of sacroiliitis on MRI/X-rays but with >2 SpA features and signs of bone oedema on MRI spine (nr-axSpA MRI SIJ-/undifferentiated SpA). Significant differences were found in the prevalence of radiographic sacroiliitis, active sacroiliitis on MRI and SPARCC SIJ scores. Biomarker levels were not significantly increased in any of the patient groups. The correlations between IL-17 and IL-23 and other indices were not significant; correlations were found between IL-22 and BASFI, BASG1, HAQ, VAS pain, between mSASSS and MMP3, and between the latter and hsCRP. Although not significantly higher in any of the three groups, IL-22, MMP3 and hsCRP values were correlated with some disease activity indexes and with mSASSS. Large observational studies are required to confirm these preliminary findings.

Optical Manipulation of a Magnon-Photon Hybrid System.

We demonstrate an all-optical method for manipulating the magnetization in a 1-mm yttrium-iron-garnet (YIG) sphere placed in a ∼0.17 T uniform magnetic field. A harmonic of the frequency comb delivered by a multi-GHz infrared laser source is tuned to the Larmor frequency of the YIG sphere to drive magnetization oscillations, which in turn give rise to a radiation field used to thoroughly investigate the phenomenon. The radiation damping issue that occurs at high frequency and in the presence of highly magnetizated materials has been overcome by exploiting the magnon-photon strong coupling regime in microwave cavities. Our findings demonstrate an effective technique for ultrafast control of the magnetization vector in optomagnetic materials via polarization rotation and intensity modulation of an incident laser beam. We eventually get a second-order susceptibility value of ∼10^{-7} cm^{2}/MW for single crystal YIG.

Spine and sacroiliac joints on magnetic resonance imaging in patients with early axial spondyloarthritis: prevalence of lesions and association with clinical and disease activity indices from the Italian group of the SPACE study.

Our aim was to determine the prevalence of spine and sacroiliac joint (SIJ) lesions on magnetic resonance imaging (MRI) in patients with early axial spondyloarthritis (axSpA) and their correlation with disease activity indices. Sixty patients with low back pain (LBP) (≥3 months, ≤2 years, onset ≤45 years), attending the SpA-clinic of the Unità Operativa Complessa Reumatologia of Padova [SpondyloArthritis-Caught-Early (SPACE) study], were studied following a protocol including physical examination, questionnaires, laboratory tests, X-rays and spine and SIJ MRI. Positive spine and SIJ MRI and X-rays images were scored independently by 2 readers using the SPARCC method, modified Stoke ankylosing spondylitis spine score and New York criteria. The axial pain and localization of MRI-lesions were referred to 4 sites: cervical/thoracic/lumbar spine and SIJ. All patients were classified into three groups: patients with signs of radiographic sacroiliitis (r-axSpA), patients without signs of r-axSpA but with signs of sacroiliitis on MRI (nr-axSpA MRI SIJ+), patients without signs of sacroiliitis on MRI and X-rays (nr-axSpA MRI SIJ-). The median age at LBP onset was 29.05±8.38 years; 51.6% of patients showed bone marrow edema (BME) in spine-MRI and 56.7% of patients in SIJ-MRI. Signs of enthesitis were found in 55% of patients in the thoracic district. Of the 55% of patients with BME on spine-MRI, 15% presented presented a negative SIJMRI. There was a significant difference between these cohorts with regard to the prevalence of radiographic sacroiliitis, active sacroiliitis on MRI and SPARCC SIJ score. The site of pain correlated statistically with BME lesions in thoracic and buttock districts. Since positive spine-MRI images were observed in absence of sacroiliitis, we can hypothesize that this finding could have a diagnostic significance in axSpA suspected axSpA.

Emergent geometries and nonlinear-wave dynamics in photon fluids.

Nonlinear waves in defocusing media are investigated in the framework of the hydrodynamic description of light as a photon fluid. The observations are interpreted in terms of an emergent curved spacetime generated by the waves themselves, which fully determines their dynamics. The spacetime geometry emerges naturally as a result of the nonlinear interaction between the waves and the self-induced background flow. In particular, as observed in real fluids, different points of the wave profile propagate at different velocities leading to the self-steepening of the wave front and to the formation of a shock. This phenomenon can be associated to a curvature singularity of the emergent metric. Our analysis offers an alternative insight into the problem of shock formation and provides a demonstration of an analogue gravity model that goes beyond the kinematic level.

Molecular mechanisms of pain in crystal-induced arthritis.

Crystal-induced arthritis (CIA) is characterized by an intense inflammatory reaction triggered by the deposition of monosodium urate, calcium pyrophosphate, and basic calcium phosphate crystals in articular and periarticular tissues. Severe, acute pain constitutes the most important clinical symptom in patients affected by these diseases. Pain along with redness, warmness, swelling, and stiffness in the affected joint arises abruptly in gout and disappears when the acute phase of the attack resolves. While an acute joint attack caused by calcium pyrophosphate crystals can mimic a gout flare, basic calcium phosphate crystal arthritis gives rise to a series of clinical manifestations, the most severe of which are calcific periarthritis, mostly asymptomatic, and a highly destructive arthritis known as Milwaukee shoulder syndrome, which is characterized by painful articular attacks. Pain development in CIA is mediated by several inflammatory substances that are formed after cell injury by crystals. The most important of these molecules, which exert their effects through different receptor subtypes present in both peripheral sensory neurons and the spinal cord, are prostaglandins, bradykinin, cytokines (in particular, interleukin (IL)-1ß), and substance P. The pharmacological treatment of pain in CIA is strictly associated with the treatment of acute phases and flares of the disease, during which crystals trigger the inflammatory response. According to international guidelines, colchicines, nonsteroidal anti-inflammatory drugs, and/or corticosteroids are first-line agents for the systemic treatment of acute CIA, while biologics, namely anti-IL-1ß agents, should be used only in particularly refractory cases.

Pain and microcrystalline arthritis.

Microcrystals are responsible for some of the most common and complex arthropathies which are often accompanied by intense, severe pain and inflammatory reactions. The main pathogens are crystals of monosodium urate (MSU), responsible for the gout, calcium pyrophosphate (CPP), which deposits also in various clinical forms of arthopathies, and basic calcium phosphate associated with osteoarthritis. In this context, the microcrystal arthritis is characterized by multiple, acute attacks followed by chronic pain, disability, impaired quality of life, and increased mortality. Given their chronic nature, they represent an ever more urgent public health problem. MSU and CPP crystals are also able to activate nociceptors. The pain in mycrocrystalline arthritis (MCA) is an expression of the inflammatory process. In the course of these diseases there is an abundant release of inflammatory molecules, including prostaglandins 2 and kinins. Interleukin-1 represents the most important cytokine released during the crystal-induced inflammatory process. Therefore, clinically, pain is the most important component of MCA, which lead to functional impairment and disability in a large proportion of the population. It is fundamental to diagnose these diseases as early as possible, and to this aim, to identify appropriate and specific targets for a timely therapeutic intervention.

Nonequilibrium steady-state fluctuations in actively cooled resonators.

We analyze heat and work fluctuations in the gravitational wave detector AURIGA, modeled as a macroscopic electromechanical oscillator in contact with a thermostat and cooled by an active feedback system. The oscillator is driven to a steady state by the feedback cooling, equivalent to a viscous force. The experimentally measured fluctuations are in agreement with our theoretical analysis based on a stochastically driven Langevin system. The asymmetry of the fluctuations of the absorbed heat characterizes the oscillator's nonequilibrium steady state and reveals the extent to which a feedback cooled system departs from equilibrium in a statistical mechanics perspective.

Feedback cooling of the normal modes of a massive electromechanical system to submillikelvin temperature.

We apply a feedback cooling technique to simultaneously cool the three electromechanical normal modes of the ton-scale resonant-bar gravitational wave detector AURIGA. The measuring system is based on a dc superconducting quantum interference device (SQUID) amplifier, and the feedback cooling is applied electronically to the input circuit of the SQUID. Starting from a bath temperature of 4.2 K, we achieve a minimum temperature of 0.17 mK for the coolest normal mode. The same technique, implemented in a dedicated experiment at subkelvin bath temperature and with a quantum limited SQUID, could allow to approach the quantum ground state of a kilogram-scale mechanical resonator.

Upper limits on gravitational-wave emission in association with the 27 Dec 2004 giant flare of SGR1806-20.

At the time when the giant flare of SGR1806-20 occurred, the AURIGA "bar" gravitational-wave (GW) detector was on the air with a noise performance close to stationary Gaussian. This allows us to set relevant upper limits, at a number of frequencies in the vicinities of 900 Hz, on the amplitude of the damped GW wave trains, which, according to current models, could have been emitted, due to the excitation of normal modes of the star associated with the peak in x-ray luminosity.

Wideband dual sphere detector of gravitational waves.

We present the concept of a sensitive and broadband resonant mass gravitational wave detector. A massive sphere is suspended inside a second hollow one. Short, high-finesse Fabry-Perot optical cavities read out the differential displacements of the two spheres as their quadrupole modes are excited. At cryogenic temperatures, one approaches the standard quantum limit for broadband operation with reasonable choices for the cavity finesses and the intracavity light power. A molybdenum detector, of overall size of 2 m, would reach spectral strain sensitivities of 2x10(-23) Hz(-1/2) between 1000 and 3000 Hz.