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Coauthor of an undergraduate study introducing mammalian cell culture and viability measurements. The educational work connected direct observation of living cells with quantitative assessment of survival and interpretation of experimental variation.^[ref]

Coauthor of an undergraduate study introducing mammalian cell culture and viability measurements. The educational work connected direct observation of living cells with quantitative assessment of survival and interpretation of experimental variation.^[ref]

Coauthor of an undergraduate study introducing mammalian cell culture and viability measurements. The educational work connected direct observation of living cells with quantitative assessment of survival and interpretation of experimental variation.^[ref]

Coauthor of an undergraduate study introducing mammalian cell culture and viability measurements. The educational work connected direct observation of living cells with quantitative assessment of survival and interpretation of experimental variation.^[ref]

Coauthor of an undergraduate study introducing mammalian cell culture and viability measurements. The educational work connected direct observation of living cells with quantitative assessment of survival and interpretation of experimental variation.^[ref]

A biologist who studies molecular mechanisms of living systems, especially how DNA, RNA and proteins store, express and regulate biological information. Reconstituting a process from selected components helps test which interactions are sufficient for an observed effect.

A biologist who studies microorganisms, including their growth, metabolism, interactions and effects on larger organisms. Cultivation, microscopy and sequence-based measurements provide complementary access to organisms that may be difficult to observe directly.

A scientist who studies heredity and variation. A geneticist may connect inherited traits with genes, measure how variants pass through families or populations, or alter a sequence experimentally to test its biological function.

A biologist who studies biological cells, including their organization, molecular machinery, division and interactions. Microscopy can reveal where a component is located, while a perturbation tests what that component contributes to cellular behavior.

A cell lineage follows descent of biological cells through successive divisions. DNA replication can transmit a mutation to descendant biological cells.

The cell cortex is a peripheral layer of cytoplasm beneath the cell membrane, containing the actomyosin ring during typical animal cytokinesis.

Its actin-rich network helps set surface mechanics and couples membrane motion to contractile forces. Local changes in attachment or assembly can produce a membrane bleb, while coordinated actomyosin activity can support constriction or migration. ^[ref]

Cell fusion combines biological cells into a shared cytoplasm bounded by a common cell membrane; it need not immediately fuse their cell nuclei.

A heterokaryon contains genetically different cell nuclei in a shared cytoplasm; cell fusion can create one.

Cell culture maintains biological cells outside their original organism.^[ref]

Glycosylation attaches carbohydrates to other molecules, including proteins and lipids.^[ref]

Peptide mapping compares separated peptides produced by cleavage of a protein. Matching patterns provide a chemical comparison beyond an intact protein's gel electrophoresis position.

Proteolysis cleaves peptide bonds in proteins; it differs from reduction of protein disulfide bonds.

The Rutherford model places a concentrated central electric charge inside a much larger chemical atom. In 1911, Ernest Rutherford argued that rare large deflections were predominantly single close encounters, rather than accumulated small deviations in a diffuse-charge atom. He treated the central electric charge as positive for calculation while noting that the scattering deductions did not establish its sign. He explicitly deferred atomic stability.^[ref]

The physical inference is a compact region generating a strong electric field, not a miniature hard wall. Most impact parameters miss that region, while a small subset give large deflections. The model supplies a way to infer interior structure from outgoing angles, a central use of scattering throughout atomic physics and nuclear physics. This inference does not by itself specify electron quantum states or explain spectral lines.

The repulsive model also sets a probing scale. At closest approach, conservation of energy with zero radial velocity givesFor the numerical model above, even a head-on projectile turns at $r_{\min }=2a=45.504\mathrm{fm}$. This is a calculated closest-approach distance, not a measured atomic nucleus radius. A point-charge fit can constrain how compact the scattering centre must be, but cannot directly resolve structure at distances the projectiles never reach.

The Rutherford differential cross-section must not be extrapolated to zero angle: the unscreened point model has a forward divergence, while real neutral chemical atoms exhibit the screening effect, finite beam acceptance, and accumulated small deflections. At very short separation, finite nuclear size and the nuclear force can change the interaction. Nuclear recoil changes the relation between laboratory and centre-of-mass angles for lighter targets; appreciable energy loss or repeated large deflections invalidates the simple thin-foil scattering counts. These limits delimit the calculation rather than supplying evidence for a nuclear contact collision in the early experiment.

Rutherford scattering is elastic scattering by a Coulomb potential. In the repulsive classical case, a positively charged projectile bends around a positively charged atomic nucleus. A close approach can turn it backwards without a contact collision. The calculation connects an invisible impact parameter with a measurable outgoing angle, then with a differential scattering cross-section and a detector count.

Assume a projectile of mass $m$ and electric charge $ze$, a stationary point atomic nucleus of electric charge $Ze$, and positive $z,Z$. Here $e$ is the elementary charge. Neglect nuclear recoil, electron screening effect, energy loss, and the nuclear force. With vacuum permittivity ${\epsilon }_0$, defineHere $E$ and $v$ are the incident kinetic energy and speed far from the atomic nucleus, $b\ge 0$ is the impact parameter, and $L$ is the magnitude of angular momentum. The nonrelativistic limit requires $v\ll c$, with $c$ the speed of light. The fixed-target approximation requires the target mass to be much greater than $m$. In SI, $\kappa$ has units $\mathrm{J}\mathrm{m}$, $E$ has units $\mathrm{J}$, and $b$ has units $\mathrm{m}$.

The Geiger-Marsden experiment probes the interior of a chemical atom by counting alpha particles deflected by metal foils. The surprising observation was a small population returning towards the incident side. Hans Geiger and Ernest Marsden performed the experiments under Ernest Rutherford's direction; Ernest Rutherford developed the Rutherford model in 1911. Observation and interpretation were distinct contributions.^[ref]

In 1909, a radon source and its radioactive decay products in a conical glass tube supplied alpha particles through a mica window towards a reflector. Lead shielded a fixed zinc sulfide screen from direct hits; an optical microscope resolved individual particle scintillations. Reflectors occupied the same position. Reflector-out counts tested air scattering; stacked gold foils and bare glass tested thickness and support contributions.^[ref]

Nearby source geometry blurred incidence angles. Extrapolating platinum counts uniformly over a hemisphere was an assumption, not a universal reflection probability.^[ref]