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The Gompertz curve or Gompertz function is a type of mathematical model for a time series, named after Benjamin Gompertz (1779–1865). It is a sigmoid function which describes growth as being slowest at the start and end of a given time period. The right-side or future value asymptote of the function is approached much more gradually by the ...
The doubling time is the time it takes for a population to double in size/value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time. When the relative growth rate (not the absolute growth rate) is constant ...
Proliferative index. Proliferation, as one of the hallmarks and most fundamental biological processes in tumors, [ 1] is associated with tumor progression, response to therapy, and cancer patient survival. [ 2] Consequently, the evaluation of a tumor proliferative index (or growth fraction) has clinical significance in characterizing many solid ...
At the start of his experiment he named the primary culture "phase one". Phase two is defined as the period when cells are proliferating; Hayflick called this the time of "luxuriant growth". After months of doubling the cells eventually reach phase three, a phenomenon he named "senescence", where cell replication rate slows before halting ...
The average doubling time is 19 to 50 hours. 1 mM sodium pyruvate, penicillin (100 units/ml) and streptomycin (100 μg/ml) are also commonly added to inhibit bacterial contamination. Cultures should be maintained at cell densities in the range 2-9x10 5 cells/ml at 37 °C, 5% CO 2. Cells are non-adherent. [5]
The mitotic index is a measure of cellular proliferation. [ 1] It is defined as the percentage of cells undergoing mitosis in a given population of cells. Mitosis is the division of somatic cells into two daughter cells. Durations of the cell cycle and mitosis vary in different cell types. An elevated mitotic index indicates more cells are ...
Agrobacterium tumefaciens[ 3][ 2] is the causal agent of crown gall disease (the formation of tumours) in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. [ 4] Symptoms are caused by the insertion of a small segment of DNA (known as T-DNA, for 'transfer DNA', not to be confused with tRNA that transfers amino acids ...
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all tissues and under a ...