The bright Easter bunny sign: a useful aide-memoire on MRI for costotransverse joint inflammation in axial spondyloarthritis.

AIM: To assess the significance of the "bright Easter bunny" sign on magnetic resonance imaging (MRI) to indicate inflammatory costotransverse joint (CtJ) lesions to diagnose axial spondyloarthritis (ax-SpA). MATERIALS AND METHODS: Consecutive cases of patients with ax-SpA from a specialist rheumatology clinic were analysed retrospectively over two cohorts, between 2012-2014 and 2018-2020, to determine newly diagnosed patients under the Assessment of SpondyloArthritis international Society (ASAS) criteria. Biological naive adult patients who underwent spine MRI and sacroiliac imaging with full immunological work-up and a C-reactive protein reading within 3 months of the scan were included. Blinded images were reviewed by experienced musculoskeletal radiologists. RESULT: From the 1,284 cases that were identified, 40 cases met the inclusion criteria for this study. Seven out of the 40 cases (17.5%) identified inflammatory lesions at the CtJ with five (70%) showing concordance with the bright Easter bunny sign. CONCLUSION: The bright Easter bunny sign is concordant with inflammatory costotransverse enthesitis. This aide-memoire radiological sign is often on overlooked edge-of-field sections and this emphasises the need to ensure adequate coverage of the CtJ on spine MRI protocols as an important anatomical site of inflammatory change in ax-SpA assessment.

A Comparative Analysis of the Physico-Chemical Properties of Pectin Isolated from the Peels of Seven Different Citrus Fruits.

In the present research work, pectin was isolated from the peels of seven citrus fruits (Citrus limon, Citrus limetta, Citrus sinensis, Citrus maxima, Citrus jambhiri, Citrus sudachi, and Citrus hystrix) for a comparison of its physicochemical parameters and its potential use as a thickening agent, gelling agent, and food ingredient in food industries. Among the seven citrus fruits, the maximum yield of pectin was observed from Citrus sudachi, and the minimum yield of pectin was observed from Citrus maxima. The quality of each pectin sample was compared by using parameters such as equivalent weight, anhydrouronic acid (AUA) content, methoxy content, and degree of esterification. It was observed that all seven pectin samples had a high value of equivalent weight (more than 1000), suggesting that all the pectin samples had a high content of non-esterified galacturonic acid in the molecular chains, which provides viscosity and water binding properties. The methoxy content and degree of esterification of all the pectins was lower than 50%, which suggests that it cannot easily disperse in water and can form gel only in presence of divalent cations. The AUA content of all isolated pectins samples was above 65%, which suggests that the pectin was pure and can be utilized as a food ingredient in domestic foods and food industries. From the FTIR analysis of pectin, it was observed that the bond pattern of Citrus maxima, Citrus jambhiri, and Citrus hystrix was similar. The bond pattern of Citrus limon, Citrus limetta, and Citrus sinensis was similar. However, the bond pattern of Citrus sudachi was different from that of all other citrus fruits. The difference in the bond pattern was due to the hydrophobic nature of pectin purified from Citrus limon, Citrus limetta, Citrus sudachi, and Citrus sinensis and the hydrophilic nature of pectin purified from Citrus maxima, Citrus jambhiri, and Citrus hystrix. Hence, hydrophobic pectin can be utilized in the preparation of hydrogels, nanofibers, food packaging material, polysoaps, drug delivery agents, and microparticulate materials, whereas hydrophilic pectin can be utilized for the preparation of gelling and thickening agents.

Spontaneous Rotation of Ferrimagnetism Driven by Antiferromagnetic Spin Canting.

Spin-reorientation phase transitions that involve the rotation of a crystal's magnetization have been well characterized in distorted-perovskite oxides such as orthoferrites. In these systems spin reorientation occurs due to competing rare-earth and transition metal anisotropies coupled via f-d exchange. Here, we demonstrate an alternative paradigm for spin reorientation in distorted perovskites. We show that the R_{2}CuMnMn_{4}O_{12} (R=Y or Dy) triple A-site columnar-ordered quadruple perovskites have three ordered magnetic phases and up to two spin-reorientation phase transitions. Unlike the spin-reorientation phenomena in other distorted perovskites, these transitions are independent of rare-earth magnetism, but are instead driven by an instability towards antiferromagnetic spin canting likely originating in frustrated Heisenberg exchange interactions, and the competition between Dzyaloshinskii-Moriya and single-ion anisotropies.