Domain: Healthcare — Pathophysiology
Target concept: Hepatitis B virus

Video generation prompt: Take liver tissue sections infected with hepatitis B virus and observe the morphology of viral particles under a transmission electron microscope.

Evaluation guide:
(i) Target concept: Visualization of intracellular HBV Dane particles in infected human hepatocytes via transmission electron microscopy.
Minimum mechanism: Hepatocytes must be structurally intact and infected; TEM imaging must occur *after* tissue sectioning and mounting; HBV particles must originate from and reside within hepatocytes, not added externally or mislocalized.
(ii)Storyline: [Frame 0–2] Liver tissue section (thin, rectangular, with visible hepatocyte polygons) is placed flat onto a metallic TEM stage inside a fixed viewport. [Frame 3–6] View transitions to high-magnification TEM field showing hepatocyte cytoplasm/nuclei. [Frame 7–10] Spherical, electron-dense particles appear *only* within those cellular compartments: no particles in extracellular space, stage surface, or vacuum background. Perspective remains fixed frontal TEM viewport throughout; no camera movement; all visibility relies on electron contrast, not color or illumination.

Manual:
Experimental Procedure
1. Mount thin-sectioned human liver tissue infected with HBV onto TEM specimen stage.
2. Insert stage into transmission electron microscope.
3. Focus and acquire high-magnification image of hepatocytes.
Observation of Experimental Phenomena
Spherical, electron-dense HBV Dane particles are visible exclusively inside hepatocyte cytoplasm and nuclei — never extracellularly — and each is clearly smaller than the surrounding nucleus.
Summary of Experimental Principles
HBV replicates intracellularly; nucleocapsids assemble in the hepatocyte cytoplasm and acquire their outer envelope by budding into multivesicular-body/ER-derived membranes (an ESCRT-associated pathway), not by budding at the Golgi. TEM reveals ultrastructure: double-shelled Dane particles with an inner nucleocapsid core and an outer surface-antigen envelope.

Prompt Grounding rubric:
level_1: No liver tissue section is shown; no TEM stage or viewport is shown; no particle-like structures of any kind appear; none of the three required elements (tissue section, TEM apparatus, viral particles) co-occur.
level_2: At least one element appears alone (a generic tissue slice, or a generic microscope field) but the section is never shown mounted on a TEM stage together with particles, or the section-to-imaging sequence isn't represented, or particles are missing or clearly misplaced relative to any cell.
level_3: All three elements appear (a liver tissue section, a TEM viewport, and round particle-like structures inside what read as cells) in the order section-placement then observation; but the particles show no core-plus-rim density contrast that would distinguish them from generic dark dots, and/or some particles float free outside any cell boundary.
level_4: Everything in level 3 holds, plus the particles are uniform in size and consistently confined inside hepatocyte-like cytoplasm or nuclei rather than free space, and no anachronistic elements intrude (no light-microscope parts, no colored histology-style staining, since TEM images are grayscale), but one non-core flaw remains, such as blur obscuring particle detail in part of the field, or vignetting cropping the section's edge.
level_5: Everything in level 4 holds, plus the section sits flush and centered on the TEM stage inside a sharp, fully visible viewport; every particle shown is spherical, similarly sized, and located strictly inside cell cytoplasm or nuclei with none floating in background space; there is no cropping, blur, or extraneous object; the section-to-imaging sequence reads as one continuous, causally ordered shot.

Scientific and Causal Correctness rubric:
level_1: The round structures shown are biologically implausible as a virus (resembling bacteria, mitochondria, or shapeless blobs) with no discernible density pattern; the tissue shows no recognizable hepatocyte architecture (no polygonal cell outlines, no nuclei); there is no electron-density contrast typical of TEM anywhere in the field.
level_2: Particles appear but with implausible features for a Dane particle: strongly irregular or jagged outlines, visible internal organelle-like substructure, or a size clearly out of scale with the surrounding cell (comparable to or larger than the nucleus); the tissue shows a non-hepatic or non-mammalian cell type; particles show no density contrast at all against the surrounding cytoplasm.
level_3: Particles are spherical, consistent in size, clearly smaller than the surrounding nucleus, and sit inside cells with visibly polygonal outlines and central nuclei; but the particles appear as flat, single-density dots rather than showing any inner-versus-outer density difference, so they can't yet be told apart from a generic dark granule.
level_4: Everything in level 3 holds, plus most particles show a two-tier density pattern (a denser core with a fainter surrounding rim) consistent with a nucleocapsid-plus-envelope structure, no particle appears as a bare core sitting where a complete virion should be, and the number of particles per cell looks like a plausible viral load (scattered, not so dense as to fill the cytoplasm solid black); but one flaw remains, such as locally over-enhanced contrast making the background unnaturally pitch-black, or a break in the nuclear membrane outline.
level_5: Everything in level 4 holds, plus every particle consistently shows the two-tier core/rim density contrast, none appear as bare cores lacking the outer rim, particle size stays clearly and consistently much smaller than the nucleus and other visible organelles (mitochondria, rough ER) in the same cell, and the particle count per cell reads as a plausible viral load rather than near-zero or unnaturally saturating; the hepatocyte's own nuclear chromatin pattern and organelles look normal and undistorted around the particles.

Spatiotemporal Consistency rubric:
level_1: The tissue section or TEM viewport appears or disappears abruptly between frames; the viewport jumps to a completely unrelated field of view; particles jump position across the frame with no visible path; brightness flips suddenly between bright and near-black with no transition; the section appears to fracture with mismatched edges mid-sequence.
level_2: The section rotates or changes apparent scale with no plausible mechanical cause; particles blink in or out of existence with no path of motion; the viewport crops in or out erratically; the direction of shading on cell or particle surfaces reverses abruptly between adjacent frames with no camera or lighting cue to explain it; hepatocyte cell boundaries warp, dissolve, and then reappear.
level_3: Only small, easy-to-miss flaws remain: a slight wobble in the viewport framing, one moment where a particle's opacity flickers between translucent and solid with no cause, a barely perceptible shift in the section's position; but there is no vanishing, no structural tearing, and no shading reversal; the scene otherwise reads as essentially still, consistent with a static TEM capture.
level_4: The section stays fixed in position and orientation; the viewport holds steady centering and magnification; particles stay static relative to the surrounding cell landmarks; there is no flicker, jitter, or rescaling; shading and contrast stay consistent frame to frame, aside from one small non-disruptive artifact, such as a single frame of mild ghosting during the transition from mounting to imaging.
level_5: The section sits motionless on the stage with no visible displacement or distortion; the viewport is completely steady with no drift, zoom, pan, or rotation; every particle keeps a fixed position relative to the cell structures around it across the whole clip; contrast and shading stay identical frame to frame; there are no frame-to-frame artifacts, no motion blur, and no break in continuity; the full clip reads as one continuous, static TEM image capture.