STRC Research

AUDIT-h02

6 min read

AUDIT — h02-piezo (Piezoelectric TM Bioelectronic Amplifier)

  • Tier: C · mech 2 / deliv 1 / misha_fit 5
  • lit_audit before: partial (2026-04-25), free-text lit_audit_note, no lit_audit_blockers list at all
  • lit_audit after: partial, 3 blockers enumerated as a proper YAML list
  • Grounding: GROUNDING/hypc-h02-piezo.md

Schema defect found first

h02’s hub carries its audit state in a single 900-character free-text lit_audit_note: string. There is no lit_audit_blockers: list. Under the route’s done-criteria a non-fixed hub must carry an enumerated blocker list, so a prose blob that buries three open items mid-sentence does not qualify — it cannot be counted, queried by Dataview, or checked off. The note’s content is good; its shape is wrong. apply.sh converts it to a list and retains the narrative history in the audit note.

Prior work read

  • hypotheses/h02-piezo/index.md, log.md
  • phases/STRC h02 Parameter Provenance Audit 2026-04-23.md
  • phases/STRC h02 Parameter Provenance Audit 2026-04-25.md
  • models/piezo_voltage_budget.py, piezo_phase2_frequency_bundle.py, piezo_phase3_delivery_feasibility.py
  • parameters/tectorial-membrane.md, parameters/piezoelectric-materials.md

Parameter-provenance table

#ConstantValueUnitsClaimed sourceLocal sources/lit/ fileStatus
1TM Young’s modulus, basal24.3 ± 25.2kPaTeudt & Richter 2014 JARO 15:675, PMID 248657662026-04-25-teudt-2014-tm-bm-stiffness-cba-mouse.md✅
2TM Young’s modulus, middle / apical5.1 / 1.9kPasamesame✅
3TM Young’s modulus “210 kPa”210kPa”Masaki 2009 PLoS One 4:e4877” — PHANTOM—❌ NO PRIMARY SOURCE; phantom string still live at piezo_voltage_budget.py:262
4TM shear modulus G′2.0–6.5kPaShoelson 2004 Biophys J 87:27682026-04-25-shoelson-2004-…-biophysj.md✅ (context; guinea pig, shear ≠ Young’s)
5TM fiber modulus~1kPaGavara & Chadwick 2009 PLoS One 4:e48772026-04-25-gavara-2009-…-afm.md✅
6TM displacement at 60 dB SPL5–30nmnone — in-house table—🔶 model assumption; anchor Lee 2015 PNAS PMID 25737536
7PVDF-TrFE d33 (80/20)25–28pC/NHu 2021 Front Energy Res 9:6215402026-04-25-hu-2021-…-frontiers-energy.md✅ for 80/20
8PVDF-TrFE d31 (70/30)−12pC/NArkema datasheet (inaccessible)—🔶 inferred from d33 × ratio 0.4–0.5
9OHC specific membrane capacitance0.9µF/cm²Gentet 2000 Biophys J 79:314cited in script✅
10V_saturation_mV70mVnone—❌ NOT-MODELABLE AS POSED — see below
11V_threshold_mV10mVSantos-Sacchi 1991 J Neurosci 11:3096—🔶 “model simplification” per script’s own comment
12OHC specific membrane resistance~kΩ·cm²Ω·m²”generic excitable membrane”—❌ OPEN — retrievable, not yet retrieved (2 attempts)
13PVDF-TrFE Young’s modulus3GPamaterial property—⚙

Retrieval performed this run

targettoolexact queryoutcome
OHC membrane resistanceWebSearchouter hair cell specific membrane resistance kOhm cm2 basolateral input resistance measurement Housley Ashmorequalitative only; numbers stated to live in the primary papers, not the accessible reviews
OHC membrane resistanceWebFetchAshmore 2008 OHC Motility review PDF (UCLA open copy)fetch returned PDF structure, not body text — no values
V_saturationWebSearchprestin nonlinear capacitance Boltzmann parameters Vpkcm valence z Qmax outer hair cell Santos-Sacchi measured valuesreframing found — prestin NLC is Boltzmann (Vh, z, Qmax); no discrete saturation voltage exists

All persisted verbatim in GROUNDING/hypc-h02-piezo.md.

The V_saturation finding

This is the substantive result of the h02 pass, and it is a reclassification rather than a retrieval.

Prestin’s voltage dependence is fit as a Boltzmann — bell-shaped NLC peaking at Vh, charge transfer asymptoting to Qmax. An asymptote has no saturation voltage. So V_saturation = 70 mV is not an unsourced measurement that better searching will find; no paper reports it because the quantity does not exist. Four months of “V_saturation unsourced — needs literature” in the hub was therefore chasing something unfindable.

The sourced replacement is the Boltzmann triple (Vh, z, Qmax), which is measured routinely — this run surfaced z = 0.92 (guinea pig OHC), z = 1 (mouse OHC), via a modelling paper’s restatement, so a VARIANT and not script-ready. Named follow-up: retrieve Santos-Sacchi’s primary NLC papers, file to sources/lit/, and reparameterize piezo_voltage_budget.py on (Vh, z, Qmax) instead of a ceiling voltage.

Because the parameter as posed is unobtainable in principle, blocker #10 carries a not-modelable reason inside an overall partial hub. The hub cannot be not-modelable as a whole, because blocker #12 is straightforwardly retrievable and #3 is a deletion, not a measurement gap. Mixing the two would misrepresent both.

The phantom that outlived its own correction

models/piezo_voltage_budget.py:262 still contains, today:

"to 210 kPa (basal) per Masaki 2009 PLOS One 4:e4877; PVDF-TrFE "

and line 271 still sets "E_TM_basal_kPa": 210.

“Masaki 2009 PLoS One 4:e4877” was identified as a phantom on 2026-04-23; that DOI is Gavara & Chadwick 2009 (fiber modulus ~1 kPa). The 2026-04-25 audit corrected parameters/tectorial-membrane.md and explicitly noted the script value was “flagged for user decision” — and there it has sat. The measured counterpart (24.3 kPa basal, Teudt 2014) disagrees with 210 kPa by ~10×.

This is the §0c triggering failure mode reproduced in miniature: the provenance table is clean, the executable is not. A future run that greps the parameter tables will see ✅ and never look at line 262. The remedy is a script edit, not a search — out of this route’s scope (I audit literature; I do not edit vault code), so it is enumerated as blocker #1 with the exact file and line numbers so the fix is a two-minute job for whoever owns h02’s code.

Note that this cuts toward h02’s known mechanical-mismatch problem, not away from it: at the real 24.3 kPa basal / 1.9 kPa apical, PVDF-TrFE at 3 GPa is 10⁵–10⁶× stiffer than the TM, worse than the 10⁴–10⁵× the tables record. h02 is C-tier partly for this reason; correcting the number makes the case against the mechanism stronger, not weaker.

Verdict

lit_audit: partial · lit_audit_date: 2026-08-21 · 3 blockers

lit_audit: partial
lit_audit_date: 2026-08-21
lit_audit_blockers:
  - "TM Young's modulus 210 kPa — PHANTOM VALUE STILL LIVE IN CODE. models/piezo_voltage_budget.py:262 still cites 'Masaki 2009 PLOS One 4:e4877' (identified as a phantom on 2026-04-23; that DOI is Gavara & Chadwick 2009, ~1 kPa fiber modulus) and line 271 still sets E_TM_basal_kPa = 210. The measured counterpart is Teudt & Richter 2014 (PMID 24865766): 24.3 +/- 25.2 kPa basal, 5.1 kPa middle, 1.9 kPa apical, already in sources/lit/. Remedy is a SCRIPT EDIT (delete 210, substitute 24.3 basal), not further retrieval. Parameter tables were corrected 2026-04-25; the executable was not."
  - "V_saturation_mV = 70 (models/piezo_voltage_budget.py:94) — NOT MODELABLE AS POSED. Prestin's voltage dependence is a Boltzmann (NLC peaks at Vh; charge asymptotes to Qmax), so no discrete saturation voltage exists and no paper will report one. Confirmed 2026-08-21 by WebSearch over the Santos-Sacchi NLC literature, independently agreeing with parameters/piezoelectric-materials.md:46. Fix is reparameterization on the measured Boltzmann triple (Vh, z, Qmax) — z = 0.92 guinea pig / 1 mouse surfaced this run but only via a modelling paper's restatement, so primary Santos-Sacchi NLC papers still need retrieval into sources/lit/."
  - "OHC specific membrane resistance (~kOhm.cm2) — OPEN AND RETRIEVABLE, not yet retrieved. 2 attempts 2026-08-21 (WebSearch; WebFetch of the Ashmore 2008 open review, which returned PDF structure not body text). This is classical OHC electrophysiology and IS measured; calling it a confirmed absence would be false. Named next step: Housley & Ashmore 1992 J Physiol 448:73-98 via Anna's Archive, parse with 'mineru -p <in> -o <out> -b vlm-engine', file a sources/lit/ note, take specific membrane resistance directly."

Ranking delta

C-tier HELD. No mech/deliv/misha_fit change recommended — see RANKING-DELTA.md.

Graph View