High-fidelity spin qubit operation and algorithmic initialization above 1 K.

The encoding of qubits in semiconductor spin carriers has been recognized as a promising approach to a commercial quantum computer that can be lithographically produced and integrated at scale1-10. However, the operation of the large number of qubits required for advantageous quantum applications11-13 will produce a thermal load exceeding the available cooling power of cryostats at millikelvin temperatures. As the scale-up accelerates, it becomes imperative to establish fault-tolerant operation above 1 K, at which the cooling power is orders of magnitude higher14-18. Here we tune up and operate spin qubits in silicon above 1 K, with fidelities in the range required for fault-tolerant operations at these temperatures19-21. We design an algorithmic initialization protocol to prepare a pure two-qubit state even when the thermal energy is substantially above the qubit energies and incorporate radiofrequency readout to achieve fidelities up to 99.34% for both readout and initialization. We also demonstrate single-qubit Clifford gate fidelities up to 99.85% and a two-qubit gate fidelity of 98.92%. These advances overcome the fundamental limitation that the thermal energy must be well below the qubit energies for the high-fidelity operation to be possible, surmounting a main obstacle in the pathway to scalable and fault-tolerant quantum computation.

Anti-SSA Ro52 and anti-Ro60 autoantibodies: association with clinical phenotypes.

OBJECTIVES: Anti-SSA autoantibodies can be differentiated according to their antigenic target proteins as anti-Ro60 (60 kDa) or anti-Ro52 (52 kDa). Anti-SSA(Ro60) antibodies are clearly associated with connective tissue diseases (CTD), but the clinical significance of anti-SSA(Ro52) antibodies remains unclear. The aim of the present study was to analyse the disease phenotype of patients with anti-Ro52 and/or anti-Ro60 antibodies. METHODS: A multicentre, cross-sectional study was carried out of positive anti-Ro52 and/or Ro60 antibodies patients followed at 10 Rheumatology centres from January 2018 until December 2021. Patients were categorised into 3 groups: group 1 (Ro52+/Ro60-); group 2 (Ro52-/Ro60+); group 3 (Ro52+/Ro60+). Antinuclear antibodies were evaluated by indirect immunofluorescence assay and further screened for anti-extractable nuclear antigen (ENA) antibodies. Demographicsand clinical data were compared between the 3 groups, by patients' medical chart review. Univariate analysis was performed and subsequently logistic regression was used to identify intergroup differences and calculate the odds ratio with a 95% confidence interval (95% CI). RESULTS: We included 776 patients [female: 83.1%; median age: 59 (46-71) years]. Groups 1, 2, and 3 comprised 31.1%, 32.6%, and 36.3% of the patients, respectively. Anti-Ro52 antibody alone was more frequently associated with non-rheumatic diseases, older age, and men (p<0.05). Among patients with CTD, the diagnosis of systemic lupus erythematosus is 3 and 2 times more prevalent in groups 2 and 3, respectively, than in group 1 [OR 2.8 (95% CI 1.60, 4.97), p<0.001; OR 2.2 (95% CI 1.28, 3.86), p<0.01]. In group 2, the diagnosis of undifferentiated CTD is more frequent than in the other groups. Group 1 was more frequently associated with inflammatory myositis than group 2 [OR 0.09 (95% CI 0.01, 0.33), p<0.001] or group 3 [OR 0.08 (95% CI 0.01, 0.29), p<0.001]. Group 1 was also more frequently associated with arthritis (p<0.01), interstitial lung disease (p<0.01), and myositis (p<0.01). CONCLUSIONS: Anti-Ro52+ antibody alone is frequently found in patients with non-rheumatic diseases. In addition, anti-Ro52+ antibody is also prevalent in patients with CTD and associated with clinical phenotypes that are different from anti-Ro60+ antibody.

Agreement between local and central anti-synthetase antibodies detection: results from the Classification Criteria of Anti-Synthetase Syndrome project biobank.

OBJECTIVES: The CLASS (Classification Criteria of Anti-Synthetase Syndrome) project is a large international multicentre study that aims to create the first data-driven anti-synthetase syndrome (ASSD) classification criteria. Identifying anti-aminoacyl tRNA synthetase antibodies (anti-ARS) is crucial for diagnosis, and several commercial immunoassays are now available for this purpose. However, using these assays risks yielding false-positive or false-negative results, potentially leading to misdiagnosis. The established reference standard for detecting anti-ARS is immunoprecipitation (IP), typically employed in research rather than routine autoantibody testing. We gathered samples from participating centers and results from local anti-ARS testing. As an "ad-interim" study within the CLASS project, we aimed to assess how local immunoassays perform in real-world settings compared to our central definition of anti-ARS positivity. METHODS: We collected 787 serum samples from participating centres for the CLASS project and their local anti-ARS test results. These samples underwent initial central testing using RNA-IP. Following this, the specificity of ARS was reconfirmed centrally through ELISA, line-blot assay (LIA), and, in cases of conflicting results, protein-IP. The sensitivity, specificity, positive likelihood ratio and positive and negative predictive values were evaluated. We also calculated the inter-rater agreement between central and local results using a weighted κ co-efficient. RESULTS: Our analysis demonstrates that local, real-world detection of anti-Jo1 is reliable with high sensitivity and specificity with a very good level of agreement with our central definition of anti-Jo1 antibody positivity. However, the agreement between local immunoassay and central determination of anti-non-Jo1 antibodies varied, especially among results obtained using local LIA, ELISA and "other" methods. CONCLUSIONS: Our study evaluates the performance of real-world identification of anti-synthetase antibodies in a large cohort of multi-national patients with ASSD and controls. Our analysis reinforces the reliability of real-world anti-Jo1 detection methods. In contrast, challenges persist for anti-non-Jo1 identification, particularly anti-PL7 and rarer antibodies such as anti-OJ/KS. Clinicians should exercise caution when interpreting anti-synthetase antibodies, especially when commercial immunoassays test positive for non-anti-Jo1 antibodies.

Granulomatosis With Polyangiitis and Concomitant Superinfection: A Defying Diagnosis and Management Approach.

Granulomatosis with polyangiitis (GPA) is a systemic necrotizing vasculitis mainly involving the ear, nose, and upper and lower airways. Diagnosis is based on clinical manifestations, positive antineutrophil cytoplasmic antibodies (ANCA) serology, and histopathological findings. We report a case of inflammatory polyarthralgia with a high titer of rheumatoid factor (RF), which was revealed to be GPA after extensive diagnosis workup. However, the disease was complicated by superinfections, which delayed and limited immunosuppressive treatment. Methotrexate was at last initiated with antibiotic prophylaxis, and there was significant clinical improvement. This case underlines the importance of an adequate diagnosis workup and the difficulties that often arise when other entities are present.

10-year experience of early arthritis clinic at a tertiary rheumatology center: achievements and challenges.

OBJECTIVES: To characterize patients evaluated in our Early Arthritis Clinic (EAC) in the first ten years; to assess diagnostic delay and its underlying causes; and to evaluate the level of agreement between the referring physician and the rheumatologist regarding the presence of referral criteria. METHODS: Cross-sectional study including patients attending EAC between 2012 and 2021. Demographic data, provenience, final diagnosis, referral criteria and time related to diagnosis delay were retrieved from clinical files and the Portuguese Registry of Rheumatic Patients (reuma.pt). Characteristics of the patients and the time variables were analysed with descriptive statistical analysis. The agreement between the referring physician and rheumatologist regarding the referral criteria was evaluated using Cohen's Kappa. RESULTS: A total of 440 patients (68.9% females, mean age of 54±16.7 years) were referred, mostly from primary care (71.6%). Inflammatory Rheumatic Disease was diagnosed in 65.7% of the patients, with 58.9% classified as early arthritis. The median time from onset of symptoms to referral for EAC was 76 days (IQR 33.5-144.0); the median time from referral to the first EAC was 34 (IQR 19.0-46.0) days, and the median time from onset of symptoms to first EAC was 114.5 (IQR 66.8-190.3) days (16.3 weeks). Only about 10% were observed by a Rheumatologist before six weeks after symptom onset. The level of agreement between the referring physician and the rheumatologist was slight to fair to clinical criteria and moderate to substantial to laboratory criteria. CONCLUSIONS: A significant delay still is observed in patients with early arthritis suspicion, being the time from onset of symptoms to referral is the most relevant. A low agreement between referral and Rheumatologists suggests that non-rheumatologists education/training is needed. Identifying the barriers that prevent the adequate referral of patients is necessary to define strategies to improve it.

Phytochemical composition of aerial parts and roots of Pfaffia glomerata (Spreng.) Pedersen and anticholinesterase, antioxidant, and antiglycation activities.

The Pfaffia glomerata, a plant popularly called Brazilian ginseng, is widely used in Brazil for the treatment of various pathologies, including those associated with the Central Nervous System. 20-hydroxyecdysone (20E), a phytosteroid present in this plant, can promote adaptogenic effects in the organism, providing greater body resistance to stressors. This study aimed to evaluate the phytochemical composition and the anticholinesterase, antioxidant, and antiglycation effects of extracts and fractions of aerial parts and roots of P. glomerata, also analyzing their possible cytotoxic effects. The fractions were obtained by partitioning methanol extracts from the aerial part and roots of P. glomerata with hexane, dichloromethane, ethyl acetate, n-butanol, and water. The samples were initially tested in anticholinesterase, antioxidant, and antiglycation assays, and the most promising samples were submitted for cytotoxicity and chromatographic analyses. Mass spectrometry and chromatography methods revealed that 20E was the main compound in the dichloromethane fractions, there being 35% more 20E in the aerial part (APD) than in the roots (RD). Added to the higher concentration of 20E, the APD fraction also presented more promising results than the RD fraction in anticholinesterase and antioxidant analyses, indicating that their effects may be related to the concentration of 20E. These same fractions showed no hemolytic effects but were cytotoxic in high concentrations. These new findings contribute to scientific information about P. glomerata and open more perspectives for the understanding of its therapeutic properties, allowing the association of biological activity with the presence of 20E.

Bounds to electron spin qubit variability for scalable CMOS architectures.

Spins of electrons in silicon MOS quantum dots combine exquisite quantum properties and scalable fabrication. In the age of quantum technology, however, the metrics that crowned Si/SiO2 as the microelectronics standard need to be reassessed with respect to their impact upon qubit performance. We chart spin qubit variability due to the unavoidable atomic-scale roughness of the Si/SiO2 interface, compiling experiments across 12 devices, and develop theoretical tools to analyse these results. Atomistic tight binding and path integral Monte Carlo methods are adapted to describe fluctuations in devices with millions of atoms by directly analysing their wavefunctions and electron paths instead of their energy spectra. We correlate the effect of roughness with the variability in qubit position, deformation, valley splitting, valley phase, spin-orbit coupling and exchange coupling. These variabilities are found to be bounded, and they lie within the tolerances for scalable architectures for quantum computing as long as robust control methods are incorporated.