| eclipse phase | The time between infection by (or induction of) a bacteriophage, or other virus, and the appearance of mature virus within the cell; an interval of time during which viral infectivity cannot be recovered. Synonym: eclipse phase. (05 Mar 2000) |
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| eruptive phase | That period in the tooth formation which includes the development of the roots, periodontal ligament, and dentogingival junction of the tooth. (05 Mar 2000) |
| external phase | The medium or fluid in which a disperse is suspended. Synonym: continuous phase, dispersion medium, dispersion phase, external medium. (05 Mar 2000) |
| lag phase | <cell culture> The initial growth phase of a culture, during which cell number remains relatively constant prior to rapid growth. (09 Oct 1997) |
| lamellar phase | <biochemistry> A lamellar organisation of phospholipids that are packed as a bilayer with hydrophobic acyl tails inwardly directed and polar head groups on the outside surfaces. It is this bilayer that forms the basis of membranes in cells, though in most cellular membranes a very substantial proportion of the area may be occupied by integral proteins. The triple layered appearance of membranes seen in electron microscopy is thought to arise because the osmium tetroxide binds to the polar regions leaving a central, unstained, hydrophobic region. (31 Dec 1997) |
| follicular phase | <gynaecology, physiology> The follicular phase is the pre-ovulatory phase of a woman's reproductive cycle during which the follicle grows and high oestrogen levels cause the uterine lining to grow. (09 Oct 1997) |
| late luteal phase dysphoric disorder | <syndrome> A combination of emotional, physical, psychological, and mood disturbances that occur after ovulation and normally end with the onset of the menstrual flow. (12 Dec 1998) |
| latency phase | In psychoanalytic personality theory, the period of psychosexual development in children, extending from about age 5 to the beginning of adolescence at age 12, during which the apparent cessation of sexual preoccupation during this period stems from a strong, aggressive blockade of libidinal and sexual impulses in an effort to avoid oedipal relationships; during this phase, boys and girls are inclined to choose friends and join groups of their own sex. Synonym: latency period. (05 Mar 2000) |
| late-phase response | Recurrence of symptoms after an appreciable interval following challenge with an antigen; preceded by an initial early-phase response. (05 Mar 2000) |
| logarithmic phase | <cell culture> The steepest slope of the growth curve of a culture--the phase of vigorous growth during which cell number doubles every 20-30 minutes. (15 Nov 1997) |
| L-phase variants | Bacterial variant's which do not have rigid cell walls but which may contain varying amounts of cell wall material; they are spherical to coccobacillary in shape and vary in size from small bodies that pass through filters which retain bacteria to bodies that are larger than the bacterial form; they are Gram-negative and resistant to penicillin; some revert to the bacterial phase upon removal of the inducing substance, whereas others do not; the variant's differ greatly from the parent bacterial cells in mode of reproduction, physiology, growth requirements, and individual and colonial morphology; they are generally considered to be nonpathogenic, even if derived from a pathogenic bacterium. Origin: L. Fr. Lister Institute (05 Mar 2000) |
| luteal phase | The post-ovulatory phase of a woman's cycle, the corpus luteum produces progesterone, which in turn causes the uterine lining to secrete substances to support the implantation and growth of the early embryo. (09 Oct 1997) |
| luteal phase defect | Inadequate function of the corpus luteum that may prevent a fertilized egg from implanting in the uterus or may lead to early pregnancy loss. (09 Oct 1997) |
| luteal phase deficiency | Inadequate function of the corpus luteum that may prevent a fertilized egg from implanting in the uterus or may lead to early pregnancy loss. (09 Oct 1997) |
| lytic phase | A phase of the virus life cycleduring which the virus replicates within the host cell, releasing a new generation of viruses when the infectedcell lyses. (09 Oct 1997) |