Domain: Healthcare — Pathology
Target concept: Atrophy (senile atrophy)

Video generation prompt: A myocardial tissue specimen from an elderly individual is placed on the laboratory bench, and the intracellular structures are observed under a light microscope.

Evaluation guide:
(i) Target concept: Visualization of structural hallmarks of senile atrophy in aged myocardium via light microscopy.
Minimum mechanism: Myocardial tissue must be physically intact, free of processing artifacts, and imaged at appropriate magnification (10x–40x) to resolve myocyte caliber, interstitial proportion, and intracellular pigment; atrophy must manifest as proportional reduction in myocyte cross-section, expanded interstitial space, and visible perinuclear lipofuscin pigment granules within myocyte cytoplasm, without secondary pathology.
(ii)Storyline: [Phase 1] Static wide shot: intact myocardial specimen centered on standard lab bench surface. [Phase 2] Seamless cut or smooth zoom-in to microscope stage showing specimen aligned under objective. [Phase 3] Continuous focus transition yielding stable, in-focus microscopic field. [Phase 4] Final frame holds a static micro-view showing unambiguous atrophic morphology (smaller myocytes, wider interstitial gaps, and visible perinuclear brown-yellow lipofuscin pigment granules within myocyte cytoplasm). All phases maintain a fixed viewpoint, consistent lighting, and zero object replacement. Visibility constraint: No labels, arrows, or annotations; all diagnostic features must be self-evident from raw optical appearance.

Manual:
Experimental Procedure
1. Place myocardial tissue specimen on clean laboratory bench.
2. Position specimen directly under light microscope objective lens.
3. Adjust focus to obtain sharp microscopic field.
Observation of Experimental Phenomena
Under light microscopy: reduced cardiac myocyte diameter, increased interstitial space, preserved cross-striations, perinuclear brown-yellow lipofuscin pigment granules within myocyte cytoplasm ("brown atrophy"), and no inflammatory cells or necrosis.
Summary of Experimental Principles
Senile atrophy: age-related reduction in myocyte size due to protein synthesis decline and autophagy imbalance; histologically characterized by myocyte shrinkage with maintained architecture, accumulation of lipofuscin pigment (a byproduct of incomplete autophagic digestion of oxidized lipids) within myocytes, and expanded connective tissue matrix.

Prompt Grounding rubric:
level_1: No myocardial tissue specimen is visible; no laboratory bench is shown; no light microscope appears; neither the placement of the specimen nor an observation action is depicted.
level_2: At least one of the specimen, bench, or microscope is present, but they are not shown together or functionally connected; the placement and observation actions are missing, or attributed to the wrong objects.
level_3: The myocardial specimen is placed on the laboratory bench, a light microscope is present in the same scene, and the specimen is positioned under the microscope's objective lens with visible alignment; no microscopic field is yet shown at this stage.
level_4: All conditions for score 3 hold, AND the video transitions from the macro view (specimen on the bench) to a clear, static, in-focus microscopic field of the same tissue, with the same orientation preserved and no object teleportation or substitution.
level_5: All conditions for score 4 hold, AND the microscopic field stays in sharp, stable focus for its full duration with no drift into blur, AND the transition between the bench view and the microscope view keeps the specimen's identity and orientation fully consistent with zero object substitution, AND no additional jump cut or discontinuity occurs beyond that single transition.

Scientific and Causal Correctness rubric:
level_1: No scientifically valid atrophy is shown: the tissue looks hyperplastic, inflamed, necrotic, or of normal size; there is no structural correlation to senile atrophy; the color, shape, or density of the tissue contradicts known pathology.
level_2: The tissue is labeled or implied as myocardial but shows non-atrophic morphology (uniform fiber size, densely packed nuclei, no widened interstitial space), or atrophy is suggested only through the wrong cues (discoloration, fragmentation, or a liquefied appearance).
level_3: The microscopic field shows myocytes with a visibly reduced cross-sectional area relative to the surrounding stroma, together with visibly widened perimysial/epimysial connective tissue space; both changes are present at once, with no contradicting features such as inflammatory cells, fibrotic nodules, or vacuolation.
level_4: All conditions for score 3 hold, AND the myocyte cytoplasm shows visible perinuclear brown-yellow pigment granules (lipofuscin) at one or both poles of the nucleus (the classic intracellular marker of 'brown atrophy'), AND there is no sign of ischemic injury (no contraction bands), no compensatory enlargement of remaining fibers, and no more than minimal nuclear pallor.
level_5: All conditions for score 4 hold, AND the field shows no processing artifact (no folding, tearing, or uneven staining), AND the myocyte borders and cross-striations stay clearly visible around the pigment granules, AND the surrounding connective tissue keeps a pale, eosinophilic (pink) appearance rather than turning blue or green, with no fat deposits or waxy amyloid-like material visible.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: the specimen jumps between positions with no motion shown; the microscope disappears and reappears more than the single sanctioned bench-to-microscope transition; the room's brightness swings between very different lighting states within a single cut; the bench surface visibly cracks or bends; the specimen's shape changes suddenly rather than through visible movement.
level_2: Several identifiable breaks occur: the specimen shifts sideways with no hand or tool moving it; outside of the single sanctioned bench-to-microscope transition, the microscope's focus changes with no matching depth-of-field transition; the bench surface's texture changes noticeably between frames; the direction the shadows fall from changes partway through the clip, inconsistent with a single fixed light source.
level_3: The specimen and microscope stay in the same place relative to each other throughout the clip, and aside from the single sanctioned cut or zoom from the bench view to the microscope view, nothing disappears or suddenly appears; the direction and brightness of the lighting stay the same from start to end, and neither the specimen nor the microscope shows any stretching, skewing, or lens-like warping.
level_4: Everything described at the 3-point level holds, AND any motion shown is physically plausible (a hand placing the specimen follows a natural arc, any stage adjustment moves smoothly along a single axis), AND the single bench-to-microscope transition is either a continuous blur-to-sharp zoom or a single clean cut that keeps the specimen's identity and orientation unambiguous, rather than a jarring or mismatched change.
level_5: All conditions for score 4 hold, AND no frame shows flicker or ghosting of the specimen or microscope, AND no visible jitter appears in the specimen's or microscope's edges between frames, AND occlusion stays consistent (the bench edge never appears to cut through the specimen mid-motion), AND within each continuous shot the specimen keeps a constant apparent depth relative to its immediate background, with no additional cut or discontinuity beyond the single sanctioned bench-to-microscope transition.