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We report ongoing experimental work on fracture and brittle-ductile transitions in vanadium, iron and iron-9% chromium single crystals and polycrystals. Tests were carried out by four-point bending of pre-cracked specimens in the temperature range 77-300 K, at a variety of strain rates. For a given material, variation of the brittle-ductile transition temperature with strain rate allows us to estimate an activation energy for the controlling process; for vanadium this was found to be $0.37 eV, for iron $0.21 eV and for iron-9% chromium $0.11 eV.

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We present a case of a malnourished 68-year old man with occult hypothyroidism who presented with malaise, pyrexia, tongue swelling, oral ulceration and dysphagia after a 6-month period of increasing lethargy and failing self-care. Severe necrotic oral ulcerative lesions were accompanied by cutaneous purpura, blood-filled blisters and bedsores. It was concluded that the patient's clinical condition reflected necrotizing stomatitis on a background of malnutrition with scorbutic skin lesions and hypothyroidism. The patient made a good recovery with scrupulous oral hygiene, debridement, intravenous metronidazole and nutritional support. Healing occurred with marked fibrosis and trismus, which has slowly improved with mouth-opening exercises. Necrotizing stomatitis is more commonly encountered in malnourished children in developing countries, and may subsequently result in devastating facial defects and death. Patients in the developed world with poor oral hygiene, malnourishment and immunosuppression are also at risk, but early diagnosis and treatment is life-saving and reduces subsequent disability.