Documentation

Introduction to CARA

CARA (Computer Aided Resonance Assignment) is a powerful software application for the analysis of Nuclear Magnetic Resonance (NMR) spectra. Designed by researchers for researchers, CARA provides comprehensive tools for spectral processing, peak detection, and molecular structure analysis.

What You Can Do with CARA

• Process 1D, 2D, 3D, and 4D NMR spectra with advanced algorithms
• Automated and manual peak picking with high precision
• Resonance assignment using integrated chemical shift databases
• Structure elucidation from NOE and coupling constant data
• Interactive 3D visualization of multi-dimensional spectra
• Export publication-quality figures and data tables
• Automate workflows with Python scripting

Installation

Windows Installation

CARA is compatible with Windows 10 and Windows 11 (64-bit).

1. Download the latest installer from the official website
2. Run the installer executable (CARA-Setup-4.0.exe)
3. Follow the installation wizard
4. Launch CARA from the Start Menu or Desktop shortcut

# Download installer via command line
Invoke-WebRequest -Uri "https://cara.nmr-software.org/download/CARA-Setup-4.0.exe" -OutFile "CARA-Setup.exe"

# Silent installation (optional)
.\CARA-Setup.exe /S

macOS Installation

CARA supports macOS 10.15 (Catalina) and later versions.

1. Download the DMG file for macOS
2. Open the downloaded DMG file
3. Drag CARA to your Applications folder
4. Launch CARA from Applications

Linux Installation

CARA is available for major Linux distributions including Ubuntu, Debian, and CentOS.

# Ubuntu/Debian installation
wget https://cara.nmr-software.org/download/cara_4.0_amd64.deb
sudo dpkg -i cara_4.0_amd64.deb
sudo apt-get install -f

# Launch CARA
cara

# CentOS/RHEL installation
wget https://cara.nmr-software.org/download/cara-4.0.x86_64.rpm
sudo rpm -ivh cara-4.0.x86_64.rpm

# Launch CARA
cara

System Requirements

Minimum Requirements

Recommended Requirements

Quick Start Guide

1. Import Your Data

CARA supports multiple NMR data formats. To import your spectrum:

• Click File → Open or press Ctrl+O (Cmd+O on Mac)
• Navigate to your data directory
• Select your spectrum file (Bruker, Varian, JCAMP-DX, etc.)
• Click Open

2. Process Your Spectrum

After importing, apply basic processing steps:

• Fourier Transform: Process → Fourier Transform
• Phase Correction: Process → Phase Correction (or press P)
• Baseline Correction: Process → Baseline Correction

# Automated processing with Python
import cara

# Load spectrum
spectrum = cara.load("path/to/data")

# Apply processing
spectrum.fourier_transform()
spectrum.phase_correct(method='auto')
spectrum.baseline_correct()

# Save processed spectrum
spectrum.save("processed_spectrum.nmr")

3. Peak Picking

Identify peaks in your spectrum:

• Automated: Analysis → Auto Peak Pick
• Manual: Click the Peak Pick tool and click on peaks
• Adjust sensitivity in the Peak Picking dialog

4. Export Results

Export your analysis results:

• Peak List: File → Export → Peak List (CSV, TXT)
• Figure: File → Export → Figure (PNG, SVG, PDF)
• Project: File → Save Project (CARA format)

Troubleshooting

Common Issues and Solutions

Issue: CARA won't start on Windows

Solution:

• Ensure you have the latest Visual C++ Redistributable installed
• Run CARA as Administrator
• Check Windows Event Viewer for detailed error messages
• Temporarily disable antivirus software

Issue: Cannot open Bruker data

Solution:

• Verify the data directory structure is intact (includes fid, acqu, acqus files)
• Check file permissions - ensure read access to all files
• Try importing the parent directory instead of individual files

Issue: Slow performance with large datasets

Solution:

• Increase memory allocation in Preferences → Performance
• Enable GPU acceleration if available
• Close unnecessary applications to free up system memory
• Process data in smaller chunks

Issue: Graphics display problems

Solution:

• Update graphics drivers to the latest version
• Disable hardware acceleration in Preferences → Display
• Adjust OpenGL settings

Frequently Asked Questions

Q: Is CARA free to use?

A: CARA offers both free and commercial licenses. Academic users can obtain a free license for non-commercial research. Commercial users require a paid license.

Q: What data formats does CARA support?

A: CARA supports Bruker TopSpin, Varian/Agilent VNMR, JCAMP-DX, NMRPipe, Sparky UCSF, NMRView, and several other common NMR formats.

Q: Can I automate repetitive tasks?

A: Yes! CARA provides a comprehensive Python API for scripting and automation. You can create custom workflows and batch process multiple datasets.

Q: Does CARA work with protein NMR?

A: Absolutely. CARA includes specialized tools for protein structure determination, including NOE assignment, backbone assignment, and structure validation features.

Q: Can I run CARA on a server or cluster?

A: Yes, CARA supports headless operation for batch processing on servers. Contact us for enterprise licensing options.

Q: How do I cite CARA in my publication?

A: Please use the following citation:
CARA - Computer Aided Resonance Assignment, version 4.0, https://cara.nmr-software.org