I need you to analyze the following content and extract dataset metadata following the "Datasheets for Datasets" (D4D) schema.

**Source Information:**
- File: healthnexus_row13.json
- Project Column: VOICE
- File Type: .json
- Validation: ✅ Relevant

**Instructions:**
1. Analyze the content below and extract all available dataset metadata
2. Format the output as valid YAML following the D4D schema structure
3. Include these key sections if information is available:
   - id, name, title, description
   - creators (with names, affiliations, roles)
   - purposes and intended uses
   - instances (data types, counts, representations)
   - collection_mechanisms and timeframes
   - preprocessing_strategies and cleaning
   - distribution_formats and access
   - ethical_reviews and consent
   - license_and_use_terms
   - maintainers and funding

**D4D Schema Reference:**
```yaml
# Key D4D fields (use as template):
id: dataset-identifier
name: Dataset Name
title: "Full Dataset Title"
description: "Detailed description..."

creators:
  - name: "Author Name"
    affiliation: "Institution"
    role: "Principal Investigator"

purposes:
  response: "Why was this dataset created..."

instances:
  representation: "What the data represents"
  data_type: "Type of data (text, images, etc.)"
  counts: 1000

collection_mechanisms:
  description: "How data was collected..."

# Add other relevant sections...
```

**Content to Analyze:**
```
{
  "type": "Health Data Nexus",
  "url": "https://healthdatanexus.ai/content/b2ai-voice/1.0/",
  "row": 13
}
```

**Output Instructions:**
- Provide ONLY valid YAML output (no explanations or markdown formatting)
- Start directly with the YAML content
- If specific information isn't available, omit those fields rather than guessing
- Focus on extracting concrete, factual information from the source material