2 research outputs found
Anatomy of b → c τ ν anomalies
No full textIn recent times, one of the strongest hints of Physics Beyond the Standard Model (BSM) has been the anomaly in the ratios RD and RD* measured in the charged current decays of B-mesons. In this work, we perform a comprehensive analysis of these decay modes, first in a model independent way and subsequently, in the context of composite Higgs models. We discuss in depth as to how linearly realised SU(2)L × U(1)Y symmetry imposes severe constraint on the various scenarios because of correlations with other ΔF = 1 processes and Z τ τ and Z ν ν couplings. In the composite Higgs paradigm with partial compositeness, we show that, irrespective of the flavour structure of the composite sector, constraints from ΔF = 2 processes bring the compositeness scale down to ∼ 650 GeV which is in tension with electroweak precision observables. In the presence of composite leptoquarks, the situation improves only marginally (a factor of 2 in the compositeness scale), thus making the new states soon discoverable by direct searches at the LHC. We also comment on the possible explanation of the RK,K* anomalies within the composite Higgs framework. © 2018, The Author(s)
Fluoroquinolone-nitro imidazole fixed-dose combination medication-induced fixed drug eruption with positive re-challenge
No full textFluoroquinolone-nitroimidazole fixed-dose combinations, such as ofloxacin-ornidazole and norfloxacin-tinidazole, are widely prescribed for gastrointestinal infections. However, fixed drug eruptions (FDEs) associated with these combinations are underreported. A 32-year-old female developed generalized itching and painful ulcerative lesions on the buccal mucosa shortly after taking an ofloxacin-ornidazole tablet. Upon discontinuation and substitution with norfloxacin-tinidazole by a physician, her symptoms worsened, indicating a positive rechallenge. Dermatological evaluation led to withdrawal of the drug and initiation of antihistamines and topical analgesics, resulting in symptom resolution. Her clinical course, including lesion recurrence at the same site upon re-exposure, confirmed the diagnosis of FDE, a delayed-type hypersensitivity reaction mediated by CD8+ T cells. Causality assessment using the World Health Organization-Uppsala Monitoring Centre (WHO-UMC) scale classified the reaction as certain. This case highlights the need for thorough drug history taking and the importance of avoiding re-prescription of drugs from the same pharmacological class in patients with suspected drug allergies.
