{
  "vercy": "1.0-draft",
  "publication": {
    "status": "research-draft",
    "adjudicationStatus": "unreviewed",
    "publishableCanonical": false,
    "generatedAt": "2026-09-12T11:29:12Z",
    "providers": [
      "Codex"
    ],
    "breadth": "recalled by Codex without web access - no source was read",
    "missingProviders": [],
    "pass": 2,
    "cost": {
      "grok": {
        "seconds": 20.1,
        "error": "Reading additional input from stdin...\nOpenAI Codex v0.153.4\n--------\nworkdir: R:\\02_PROJECTS\\02_Meta_Models_Platforms\\Ver.cy\\current\\thing-registry-backlog\nmodel: gpt-6-astra\nprovider: openai\napproval: never\nsandbox: read-only\nreasoning effort: none\nreasoning summaries: none\nsession id: 01a0955f-d095-7520-8c19-88fcb30ab9b4\n--------\nuser\nDescribe what is already known about one registered thing. Answer as JSON only, no prose around it.\n\nThing: N-acetyl-L-aspartic acid\nSense to describe: (none recorded)\nDomain code: PHY.MAT\nAlso known as: (none)\n\n\nContext for this batch of 1001 things:\n# Batch ",
        "usd": 0.0,
        "recall": true
      },
      "codex": {
        "seconds": 72.8,
        "error": "Reading additional input from stdin...\nOpenAI Codex v0.153.4\n--------\nworkdir: R:\\02_PROJECTS\\02_Meta_Models_Platforms\\Ver.cy\\current\\thing-registry-backlog\nmodel: gpt-6-astra\nprovider: openai\napproval: never\nsandbox: read-only\nreasoning effort: none\nreasoning summaries: none\nsession id: 01a0955f-d095-7072-9523-4080cbff6bf1\n--------\nuser\nYou are drafting a Vercy meta-model for one registered thing. Answer as JSON only, no prose around it.\n\nThing: N-acetyl-L-aspartic acid\nRegistry id: vr.tr.n-acetyl-l-aspartic-acid\nPlane / domain: PHY / PHY.MAT\nRegistry definition: (none recorded)\nNames folded "
      }
    },
    "enrichment": {
      "pass": 3,
      "engine": "claude",
      "producedAt": "2026-10-06T12:00:00Z",
      "ingestedAt": "2026-10-06T08:50:16+00:00",
      "fields": [
        "agent_conduct",
        "ethics",
        "failure_modes_and_hazards",
        "owners",
        "visual_identification"
      ]
    },
    "gate": {
      "passed": true,
      "version": "1.0",
      "at": "2026-10-07T10:10:29+00:00",
      "evidence": [
        "completeness 1.00",
        "sense: Wikidata description",
        "2 live sources",
        "review by codex: pass"
      ]
    }
  },
  "metaModel": {
    "id": "THING-Q2629377",
    "registryId": "vr.tr.n-acetyl-l-aspartic-acid",
    "name": "N-acetyl-L-aspartic acid",
    "version": "0.1.0-research.1",
    "entryKind": "thing",
    "family": "Thing Registry",
    "domain": [
      "PHY.MAT"
    ],
    "status": "research-draft"
  },
  "canonicalUrl": "https://ver.cy/models/thing/q2629377/",
  "model": {
    "registry_id": "vr.tr.n-acetyl-l-aspartic-acid",
    "name": "N-acetyl-L-aspartic acid",
    "purpose": "Enable an agent to recognise N-acetyl-L-aspartic acid, assess the identity and condition of a sample, and determine its suitability for a specified analytical or research use.",
    "definition": "N-acetyl-L-aspartic acid is the N-acetyl derivative of L-aspartic acid, present predominantly as N-acetyl-L-aspartate at physiological pH and abundant in the nervous system, where it participates in neuron-glia metabolism.",
    "scope_statement": "This model owns the chemical identity, material states, quality evidence, measurement interpretation and handling constraints of N-acetyl-L-aspartic acid under registry entry vr.tr.n-acetyl-l-aspartic-acid in PHY / PHY.MAT, with explicit relationships to its ionised forms and neighbouring compounds.",
    "in_scope": [
      "N-acetylated L-aspartic acid identity and stereochemical verification",
      "Distinction between the neutral acid, dissolved ionic species and separately identified salts",
      "Sample composition, purity, water content and physical condition",
      "Analytical identification and quantification in standards and biological matrices",
      "Evidence for storage, handling and suitability for a stated use"
    ],
    "out_of_scope": [
      "D-enantiomer and racemic N-acetylaspartic acid as independent substance identities",
      "L-aspartic acid, N-acetylglutamic acid and N-acetylaspartylglutamate as independent compounds",
      "Complete manufacturing processes and supplier product models",
      "Whole metabolic pathways, enzymes and organism models",
      "Clinical diagnosis or treatment decisions based on metabolite measurements"
    ],
    "distinguishing_features": [
      "Verify acetyl substitution on the nitrogen of L-aspartic acid rather than accepting an unmodified aspartic acid identity. [ChEBI identity](https://www.ebi.ac.uk/chebi/chebiOntology.do?chebiId=CHEBI%3A21547)",
      "Require stereochemical evidence for the L designation; molecular formula and an achiral mass measurement alone do not distinguish L, D and racemic material.",
      "Match the neutral molecular formula C6H9NO5 and stereochemically specified record, PubChem CID 65065, rather than matching the name alone. [PubChem identity](https://pubchem.ncbi.nlm.nih.gov/compound/N-Acetyl-L-Aspartic-Acid)",
      "Distinguish the neutral acid from N-acetyl-L-aspartate(2−), which results from loss of both carboxyl protons; preserve charge and counterion information. [ChEBI conjugate base](https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI%3A16953)",
      "Resolve the abbreviation NAA against an explicit structure and analytical method, including exclusion of N-acetylaspartylglutamate where relevant."
    ],
    "characteristics": [
      {
        "name": "Stereochemical identity",
        "kind": "category",
        "unit_or_values": "L confirmed; D detected; racemic; stereochemistry unresolved",
        "why_it_matters": "The registered thing specifies the L form, so an unspecified acetylaspartic acid assignment is insufficient."
      },
      {
        "name": "Identifier and structure concordance",
        "kind": "relation",
        "unit_or_values": "Structure-linked PubChem, ChEBI, CAS and EC records with source and verification date",
        "why_it_matters": "Identifiers must refer to the same stereochemistry and chemical form before records are merged."
      },
      {
        "name": "Acid-base and counterion state",
        "kind": "state",
        "unit_or_values": "Neutral acid, monoanion, dianion or unresolved mixture; pH, solvent and counterions recorded",
        "why_it_matters": "Chemical form affects formula accounting, preparation and interpretation of dissolved material."
      },
      {
        "name": "Chemical assay",
        "kind": "measurement",
        "unit_or_values": "% mass fraction or molar fraction, with method and dry/as-received basis",
        "why_it_matters": "An assay value must distinguish actual substance content from water, impurities and method-dependent peak area."
      },
      {
        "name": "Enantiomeric composition",
        "kind": "measurement",
        "unit_or_values": "% L and % D, or % enantiomeric excess, with chiral method",
        "why_it_matters": "High chemical purity does not establish stereochemical purity."
      },
      {
        "name": "Water and residual solvent content",
        "kind": "measurement",
        "unit_or_values": "% mass fraction or mg/g, with method",
        "why_it_matters": "These contributions alter weighed-dose calculations and may affect stability."
      },
      {
        "name": "Phase and thermal behaviour",
        "kind": "state",
        "unit_or_values": "Solid or solution; melting, transition or decomposition temperature in °C with method and pressure",
        "why_it_matters": "Thermal events must be identified correctly before setting processing or storage conditions."
      },
      {
        "name": "Solubility under preparation conditions",
        "kind": "measurement",
        "unit_or_values": "g/L or mol/L with solvent, pH, temperature and equilibration conditions",
        "why_it_matters": "A nominal concentration is unreliable if dissolution is incomplete."
      },
      {
        "name": "Measured analyte concentration",
        "kind": "measurement",
        "unit_or_values": "mol/L, µmol/L or µmol/g with matrix, calibration and uncertainty",
        "why_it_matters": "Results require a defined analyte basis and cannot be compared solely through the label NAA."
      },
      {
        "name": "Applicable hazard evidence",
        "kind": "relation",
        "unit_or_values": "Form-specific SDS, jurisdiction, revision date, GHS classification and exposure-limit status",
        "why_it_matters": "Handling decisions require applicable evidence; missing classification is not evidence of harmlessness."
      }
    ],
    "affordances": [
      "Reconcile a sample label with a stereochemically explicit substance identity.",
      "Calculate preparation quantities using measured assay, water content and the declared acid or salt basis.",
      "Select identification and quantification methods that address stereochemistry and relevant interfering compounds.",
      "Assess whether a material lot is suitable as an analytical standard or research reagent.",
      "Track solution preparation, storage history and evidence of chemical change.",
      "Link biological measurements to this substance while retaining uncertainty about signal specificity."
    ],
    "agent_conduct": {
      "may": [
        "Describe N-acetylaspartate and its role in the nervous system from reliable sources.",
        "Explain in general terms why it is measured in brain imaging research."
      ],
      "must_not": [
        "Interpret a person's brain spectroscopy result as a diagnosis without a qualified clinician.",
        "Present supplements of it as treatments for brain disease.",
        "Report the identity or purity of a sample without analysis."
      ],
      "requires_human": [
        "Returning findings of brain metabolite tests to a patient or family."
      ]
    },
    "ethics": {
      "considerations": [
        "Results about brain health can frighten families, especially in rare childhood disorders.",
        "Neurological data is sensitive health information."
      ],
      "affected_parties": [
        "Patients and families",
        "Children with rare metabolic disorders"
      ]
    },
    "owners": {
      "steward": "Nobody owns the compound; the laboratory or supplier answers for each sample.",
      "master_systems": []
    },
    "visual_identification": [
      "The pure acid is a white crystalline solid in a labelled vial."
    ],
    "failure_modes_and_hazards": [
      "Misread metabolite measurements can lead to wrong neurological conclusions."
    ],
    "what_it_is_for": [
      "This compound is encountered in nervous tissue and in biochemical research on metabolism between neurons and glial cells.",
      "Characterised reference samples support analytical identification and quantification in biological samples.",
      "Its signal is also studied in magnetic resonance spectroscopy of the brain."
    ],
    "standards_and_regulation": [
      "The Globally Harmonized System of Classification and Labelling of Chemicals, issued by the United Nations, provides the framework for chemical hazard classification and communication where adopted."
    ]
  },
  "sources": [
    {
      "id": "wikidata",
      "title": "Wikidata item Q2629377: N-acetyl-L-aspartic acid",
      "url": "https://www.wikidata.org/wiki/Q2629377",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    },
    {
      "id": "wikipedia-en",
      "title": "Wikipedia: N-Acetylaspartic acid",
      "url": "https://en.wikipedia.org/wiki/N-Acetylaspartic_acid",
      "url_status": "live",
      "what_it_supports": "general description of the item",
      "checked_by": "wikidata-api sitelink"
    }
  ],
  "structure": {
    "bundles": [
      {
        "id": "chemical-identity",
        "name": "Chemical identity",
        "description": "Establish exactly which acetylated aspartic acid entity is represented.",
        "rationale": "The L designation, acetyl linkage and protonation state prevent incorrect merging with related records.",
        "layers": [
          {
            "id": "structure-and-stereochemistry",
            "name": "Structure and stereochemistry",
            "description": "Separate constitutional identity from confirmation of the L form.",
            "findings": [
              {
                "id": "verify-l-acetylaspartic-identity",
                "name": "Verify L-acetylaspartic identity",
                "description": "Require evidence for both N-acetylated aspartic acid connectivity and the specified stereochemistry.",
                "questions": [
                  {
                    "text": "What structural evidence establishes N-acetylation of aspartic acid?",
                    "kind": "definition",
                    "id": "verify-l-acetylaspartic-identity-q01"
                  },
                  {
                    "text": "Which measurement or traceable certification establishes the L form and constrains D contamination?",
                    "kind": "measurement",
                    "id": "verify-l-acetylaspartic-identity-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "identifiers-and-form-boundaries",
            "name": "Identifiers and form boundaries",
            "description": "Reconcile names and identifiers without collapsing distinct chemical forms.",
            "findings": [
              {
                "id": "resolve-acid-anion-and-salt",
                "name": "Resolve acid, anion and salt",
                "description": "Maintain explicit relationships among the registered acid, its ionic species and counterion-containing materials.",
                "questions": [
                  {
                    "text": "Do the cited CAS, EC, PubChem and ChEBI records resolve to the same stereochemical structure and form?",
                    "kind": "provenance",
                    "id": "resolve-acid-anion-and-salt-q01"
                  },
                  {
                    "text": "Does this record describe the neutral acid, an ionic species in solution or a salt requiring a related identity?",
                    "kind": "boundary",
                    "id": "resolve-acid-anion-and-salt-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "material-composition-and-state",
        "name": "Material composition and state",
        "description": "Describe the actual material being weighed, dissolved or stored.",
        "rationale": "A correct substance name does not establish usable content or preparation behaviour.",
        "layers": [
          {
            "id": "assay-and-impurities",
            "name": "Assay and impurities",
            "description": "Resolve substance content, stereochemical composition and non-analyte mass.",
            "findings": [
              {
                "id": "establish-usable-content",
                "name": "Establish usable content",
                "description": "Separate chemical assay from chromatographic area purity, enantiomeric purity and water content.",
                "questions": [
                  {
                    "text": "What assay basis and uncertainty support conversion from weighed material to moles of N-acetyl-L-aspartic acid?",
                    "kind": "measurement",
                    "id": "establish-usable-content-q01"
                  },
                  {
                    "text": "What limits apply to D material, unacetylated aspartic acid, water and residual solvents for the intended use?",
                    "kind": "action",
                    "id": "establish-usable-content-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "phase-and-dissolution",
            "name": "Phase and dissolution",
            "description": "Record physical behaviour under explicit experimental conditions.",
            "findings": [
              {
                "id": "qualify-preparation-conditions",
                "name": "Qualify preparation conditions",
                "description": "Treat solubility, thermal behaviour and solution speciation as condition-dependent evidence.",
                "questions": [
                  {
                    "text": "At what solvent composition, pH and temperature does the intended concentration dissolve completely?",
                    "kind": "measurement",
                    "id": "qualify-preparation-conditions-q01"
                  },
                  {
                    "text": "Which thermal events are experimentally established, and do they represent melting, solvent loss or decomposition?",
                    "kind": "measurement",
                    "id": "qualify-preparation-conditions-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "analytical-recognition",
        "name": "Analytical recognition",
        "description": "Determine whether an observed response identifies and measures this substance.",
        "rationale": "A compatible mass or a signal labelled NAA can be less specific than the registered chemical identity.",
        "layers": [
          {
            "id": "identity-selectivity",
            "name": "Identity selectivity",
            "description": "Match analytical evidence to the distinctions it can actually resolve.",
            "findings": [
              {
                "id": "test-method-specificity",
                "name": "Test method specificity",
                "description": "Record which structural alternatives and stereoisomers the method excludes.",
                "questions": [
                  {
                    "text": "Which reference-standard, retention, fragmentation or spectroscopic evidence supports the assignment?",
                    "kind": "provenance",
                    "id": "test-method-specificity-q01"
                  },
                  {
                    "text": "Can the method distinguish L from D material and exclude relevant related compounds or overlapping signals?",
                    "kind": "boundary",
                    "id": "test-method-specificity-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "quantification-basis",
            "name": "Quantification basis",
            "description": "Preserve calibration, matrix and reporting conventions.",
            "findings": [
              {
                "id": "make-concentration-interpretable",
                "name": "Make concentration interpretable",
                "description": "Attach sufficient evidence to distinguish an absolute concentration from a relative response or metabolite ratio.",
                "questions": [
                  {
                    "text": "What calibration, recovery, matrix-effect and uncertainty evidence supports the reported amount?",
                    "kind": "measurement",
                    "id": "make-concentration-interpretable-q01"
                  },
                  {
                    "text": "Is the result an absolute concentration, a ratio or a combined signal, and on what acid-equivalent or other basis is it reported?",
                    "kind": "definition",
                    "id": "make-concentration-interpretable-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "biological-context",
        "name": "Biological context",
        "description": "Connect chemical observations to biological samples without overextending their interpretation.",
        "rationale": "Biological occurrence and measured abundance need sample-specific evidence and explicit interpretive limits.",
        "layers": [
          {
            "id": "sample-origin",
            "name": "Sample origin",
            "description": "Locate the analyte in its sampled biological context.",
            "findings": [
              {
                "id": "record-biological-provenance",
                "name": "Record biological provenance",
                "description": "Preserve organism, tissue or fluid, preparation and collection context for each observation.",
                "questions": [
                  {
                    "text": "Which organism, tissue, fluid or experimental system supplied the measured material?",
                    "kind": "provenance",
                    "id": "record-biological-provenance-q01"
                  },
                  {
                    "text": "How could collection, extraction or storage have changed the measured abundance?",
                    "kind": "measurement",
                    "id": "record-biological-provenance-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "metabolic-and-interpretive-links",
            "name": "Metabolic and interpretive links",
            "description": "Attach supported biological relationships while retaining chemical-model boundaries.",
            "findings": [
              {
                "id": "qualify-biological-inferences",
                "name": "Qualify biological inferences",
                "description": "Require evidence before assigning a measured change to a particular pathway, cell population or disease mechanism.",
                "questions": [
                  {
                    "text": "Which primary evidence supports the proposed synthesis, turnover or compartment relationship in this system?",
                    "kind": "provenance",
                    "id": "qualify-biological-inferences-q01"
                  },
                  {
                    "text": "Which interpretations require a separate pathway or clinical model beyond identifying and measuring this compound?",
                    "kind": "boundary",
                    "id": "qualify-biological-inferences-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "handling-and-use-suitability",
        "name": "Handling and use suitability",
        "description": "Translate material-specific evidence into preparation, storage and use decisions.",
        "rationale": "Research utility does not establish stability, hazard status or suitability for every application.",
        "layers": [
          {
            "id": "stability-and-storage",
            "name": "Stability and storage",
            "description": "Distinguish storage evidence for solid material from evidence for prepared solutions.",
            "findings": [
              {
                "id": "set-supported-storage-conditions",
                "name": "Set supported storage conditions",
                "description": "Base storage periods and rejection criteria on documented conditions and measured changes.",
                "questions": [
                  {
                    "text": "What evidence supports storage temperature, container, solution pH and maximum storage duration?",
                    "kind": "provenance",
                    "id": "set-supported-storage-conditions-q01"
                  },
                  {
                    "text": "Which changes in assay, impurity profile or appearance require requalification or disposal?",
                    "kind": "action",
                    "id": "set-supported-storage-conditions-q02"
                  }
                ]
              }
            ]
          },
          {
            "id": "hazards-and-grade",
            "name": "Hazards and grade",
            "description": "Connect applicable safety documentation and lot quality to the proposed operation.",
            "findings": [
              {
                "id": "qualify-authorised-use",
                "name": "Qualify intended use",
                "description": "Evaluate the actual material form, operation and grade using current applicable records.",
                "questions": [
                  {
                    "text": "Which current SDS and jurisdiction-specific records establish hazard classification, handling controls and any exposure limits?",
                    "kind": "provenance",
                    "id": "qualify-authorised-use-q01"
                  },
                  {
                    "text": "Does this lot have sufficient identity, assay and traceability evidence for the proposed analytical or research use?",
                    "kind": "action",
                    "id": "qualify-authorised-use-q02"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "evidence-and-external-alignment",
        "name": "Evidence and external alignment",
        "description": "What the world already says about this thing, gathered so the model can be checked against it.",
        "rationale": "A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.",
        "layers": [
          {
            "id": "reported-evidence",
            "name": "Reported evidence",
            "description": "Findings from the breadth pass, kept separate from the structural claims.",
            "findings": [
              {
                "id": "evidence-confidence-notes",
                "name": "Check these first",
                "description": "Recalled without web access and unsourced; every item is a lead to verify.",
                "evidence": [
                  "This description is recalled knowledge; no sources were consulted.",
                  "Verify CAS, PubChem and EC identifiers, physical constants, and grade-specific safety classifications before adding them.",
                  "NAA concentrations and spectroscopy interpretation depend on tissue, age, physiological state, and measurement method; its biological functions remain incompletely resolved."
                ],
                "questions": [
                  {
                    "id": "evidence-confidence-notes-q01",
                    "text": "Which of these check these first hold for the sense of N-acetyl-L-aspartic acid this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-identifiers",
                "name": "Identifiers and schemes",
                "description": "Recalled without web access and unsourced; every item is a lead to verify.",
                "evidence": [
                  {
                    "scheme": "Molecular formula",
                    "value_or_pattern": "C6H9NO5",
                    "note": "Formula of the neutral free acid."
                  },
                  {
                    "scheme": "Chemical nomenclature",
                    "value_or_pattern": "(2S)-2-acetamidobutanedioic acid",
                    "note": "Specifies the stereochemistry of the L form."
                  },
                  {
                    "scheme": "Biochemical abbreviation",
                    "value_or_pattern": "NAA",
                    "note": "Commonly denotes N-acetylaspartate in neuroscience; not a globally unique identifier."
                  }
                ],
                "questions": [
                  {
                    "id": "evidence-identifiers-q01",
                    "text": "Which of these identifiers and schemes hold for the sense of N-acetyl-L-aspartic acid this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-real-world-use",
                "name": "Real-world use",
                "description": "Recalled without web access and unsourced; every item is a lead to verify.",
                "evidence": [
                  "Measured by proton magnetic resonance spectroscopy as an indicator associated with neuronal integrity and metabolism.",
                  "Used as a reference compound in analytical chemistry and metabolomics.",
                  "Used in research on aspartoacylase activity, Canavan disease, and nervous-system metabolism."
                ],
                "questions": [
                  {
                    "id": "evidence-real-world-use-q01",
                    "text": "Which of these real-world use hold for the sense of N-acetyl-L-aspartic acid this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-measurements",
                "name": "Typical measurements",
                "description": "Recalled without web access and unsourced; every item is a lead to verify.",
                "evidence": [
                  {
                    "quantity": "Molar mass",
                    "typical_range": "175.14",
                    "unit": "g/mol"
                  },
                  {
                    "quantity": "Prominent acetyl-methyl proton resonance in magnetic resonance spectroscopy",
                    "typical_range": "Approximately 2.0",
                    "unit": "ppm"
                  }
                ],
                "questions": [
                  {
                    "id": "evidence-measurements-q01",
                    "text": "Which of these typical measurements hold for the sense of N-acetyl-L-aspartic acid this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-failure-modes-and-hazards",
                "name": "Failure modes and hazards",
                "description": "Recalled without web access and unsourced; every item is a lead to verify.",
                "evidence": [
                  "A reduced NAA spectroscopy signal is not specific to a single disease and does not by itself establish irreversible neuronal loss.",
                  "Overlapping N-acetylaspartylglutamate signals can complicate attribution and quantification of NAA in magnetic resonance spectra.",
                  "Confusing the free acid with a salt can produce incorrect molar concentrations when weighing material."
                ],
                "questions": [
                  {
                    "id": "evidence-failure-modes-and-hazards-q01",
                    "text": "Which of these failure modes and hazards hold for the sense of N-acetyl-L-aspartic acid this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              },
              {
                "id": "evidence-neighbours",
                "name": "Neighbouring kinds and how to tell them apart",
                "description": "Recalled without web access and unsourced; every item is a lead to verify.",
                "evidence": [
                  {
                    "name": "L-aspartic acid",
                    "difference": "Has an unacetylated amino group; NAA has an acetyl group attached to that nitrogen."
                  },
                  {
                    "name": "N-acetyl-L-aspartate",
                    "difference": "Denotes the deprotonated form of the same acid system, predominant at physiological pH."
                  },
                  {
                    "name": "N-acetyl-D-aspartic acid",
                    "difference": "Has the opposite configuration at the single stereogenic carbon."
                  },
                  {
                    "name": "N-acetylaspartylglutamate",
                    "difference": "Contains an additional glutamate residue linked through a peptide bond and is a distinct metabolite."
                  }
                ],
                "questions": [
                  {
                    "id": "evidence-neighbours-q01",
                    "text": "Which of these neighbouring kinds and how to tell them apart hold for the sense of N-acetyl-L-aspartic acid this model covers, and on what evidence?",
                    "kind": "provenance"
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  },
  "openQuestions": [
    "Which CAS and EC identifiers unambiguously identify the L free acid, and how should inconsistent supplier names or stereochemical assignments be reconciled?",
    "What measured acid dissociation constants and solubility data support speciation and preparation across relevant pH, temperature and solvent conditions?",
    "Which thermal constants are experimentally reliable, and is a boiling point meaningful before decomposition under specified conditions?",
    "What primary evidence establishes solid and solution stability, including hydrolysis or racemisation under intended handling conditions?",
    "Which current hazard classifications and exposure limits apply, and which biological analytical methods resolve this compound separately from related or combined NAA signals?"
  ],
  "statistics": {
    "bundles": 6,
    "layers": 11,
    "findings": 16,
    "questions": 26
  }
}
