| covalently closed circular DNA | <molecular biology> A circular molecule of double-stranded DNA which is supercoiled, or coiled up on itself due to internal tensions, because there are no breaks in the phosphate backbone (upon which the nucleotide bases are mounted) to relieve the tensions and allow it to form an open circle. (09 Oct 1997) |
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| head injuries, closed | Organic or functional damage resulting from trauma to the head where continuity of the scalp and mucous membranes is maintained. When brain injury results from closed head injuries, the primary cause is mechanical stretching and shearing of nerve fibres. Also common are focal intracranial lesions including haematomas and contusions. (12 Dec 1998) |
| semi-closed anaesthesia | Inhalation anaesthesia using a circuit in which a portion of the exhaled air is exhausted from the circuit and a portion is rebreathed following absorption of carbon dioxide. (05 Mar 2000) |
| semi-closed circle | A circuit for administration of an inhalation anaesthetic in which partial rebreathing with carbon dioxide absorption is combined with loss from the circuit of a portion of respired gases through valves. (05 Mar 2000) |
| ecological systems, closed | Systems that provide for the maintenance of life in an isolated living chamber through reutilization of the material available, in particular, by means of a cycle wherein exhaled carbon dioxide, urine, and other waste matter are converted chemically or by photosynthesis into oxygen, water, and food. (12 Dec 1998) |
| fractures, closed | Fractures in which the break in bone is not accompanied by an external wound. (12 Dec 1998) |