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DAx is a general purpose peak analysis program,
yet includes specialised support for
- Capillary Electrophoresis
- Gel Permeation Chromatography
- Calibrations (e.g. DNA Base Pair Count determination)
- HPLC (with Gradient Correction)
- Gas Chromatography
- RFLP analyses (with automatic size calibration)
- SNP analyses
Simple
- DAx is highly customisable: unused options can be hidden from the user
- Measurements are typed (HPLC, GC, CE, GPC, Generic). Options that are not relevant to a certain data type will not be shown
DAx Data Acquisition
- Hardware options include PCI boards and USB solutions
- Multi channel data acquisition
- Hierarchical measurement linking
- Measurement sequences using sample changers
- Automatic re-calibrations during measurement sequences
- Various measurement triggering methods
Data Analysis Algorithms
- Baseline construction and subtraction
- Peak finding … and refusal
- Automatic peak shoulder detection
- Tangent skimming
- Spike removal
- RMS and “Trumpet” noise calculation
Automatic Parameters
Analysis parameters are derived from data
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Baseline construction filter width derived from highest number
of consecutive data points with high derivative values
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Construct and subtract baseline
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Sort by absolute value
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The red lines are extrapolated to give the "Trumpet Noise Level".
This is then used to set up a threshold to find peaks.
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Shoulder Peak Detection
Automatic shoulder peak detection based on up to 4 criteria
Degree of slant
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Skim ratio
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Shoulder detected when ratio
exceeds boundary value
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Relative width
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Relative area
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Manual Editing
- Sizing data (for instance to compare / overlay them)
- Baseline corrections
- Adding, changing, removing peaks
- Marking shoulder peaks (shown)
All edit operations have 20 levels of undo.
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The many equal peaks in the plot at left are turned into shoulder
peaks using a single click and drag operation.
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Peak Qualification
Peaks are identified using an Identification Database
- Various qualifying parameters:
- peak top time, first peak moment
- peak begin or end time [ion chromatography]
- peak top elution volume
- molecular weight
- apparent mobility, effective mobility
- base pair count (calibrated value)
- coordinate relative to other peak(s)
- Various qualifying methods:
- near coordinate
- in interval (with or without area limit)
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Peak Quantification
- Various quantifying parameters:
- peak top height
- peak area
- normalised peak area
- migration time corrected peak area
- migration time corrected normalised peak area
- Various calibration curve types:
- multi-linear
- spline
- polynomial
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- Configurable per component or for entire database
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Peak Comparison Sheets
Comparing duplicate measurements
- Various qualifying parameters to determine which peaks correspond
- peak top time, first peak moment
- peak top elution volume
- molecular weight
- apparent mobility, effective mobility
- base pair count
- Sheets can be one dimensional (list) or two dimensional (binning sheet)
Data Arithmetic
- Add, subtract, multiply, divide data by constants
- Add, subtract, multiply, divide data by other data
- Fourier (optimal) filtering (see below)
- Moving average filtering
- Savitzky-Golay filtering
- Convolution and Deconvolution
Fourier Filtering
Low pass filter results
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High pass filter results
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Detail view
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Original signal
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Optimum Fourier Filtering
Original signal
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Optimum filtered
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Derive characteristics: signal to noise ratio as function of filter width
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Use optimum filter width
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Reports
- Reports can contain the following items:
- Logos (bitmaps or metafiles)
- Texts
- Variables (e.g. "filename)
- Data plots
- Peak lists
- Various calibration curves
- Lines &Rectangles
- Report editor is fully featured drawing program
- Multi page reports
- Several measurements on a single report page
- Automatic report printing when measurement ends
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Analysis Assays
Automatically determine quality of analysis
- Baseline quality (interval, drift, noise)
- Peaks quality (maximum skew, number and area of unrecognised peaks)
- Presence of required peaks
- Presence of unwanted peaks
- Calibration quality (steepness, curvature)
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DNA Fragment Analysis
- Read ABI, Amersham, SCF files
- Automatic size calibration details
- Create binning sheets to compare hundreds of samples
- Command line batch analysis enables processing of thousands of samples per day
- Locate specified base sequences in multiple samples simultaneously
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SNP Base Call Sheets
- Specify base sequence with SNP locations
- Read up to hundreds of trace files
- Base Calls Sheet displays SNP locations in overview:
- Colour-view for alignment overview:
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HPLC / GC Gradient Correction
- User entered or data derived gradients
- Convenient manual editing of gradients
- Gradient Percentages or Temperature Programme displayed as curve
- Subtracting Gradients
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The signal value Gradient Nodes can be dragged using the mouse.
(Gradient shown exaggerated here for clarity.)
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Subtract signal gradient
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The second vertical axis is for the gradient level plot.
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Capillary Electrophoresis
- Apparent and Effective mobility calculations
- Mobility axis
- Mobility tracking
- Recognising components by mobility
- Recognising components by peak begin / end coordinate
- Normalised (corrected) peak areas
- Can be used to quantify components
- Reference peaks mark EOF
- Reads ABI Genescan and Amersham MegaBACE files
Calibrations: DNA Base Pair Count Determination
- Calibration Curves (see below)
- Saving and Loading Calibrations
- Calibrated value axes:
Base Pair Count
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Calibration Curves in DAx
Calibration curves are used:
- for quantitative analysis
- to derive molecular weights in GPC
- to derive calibrated values, such as DNA base pair counts
All calibrations can take several forms:
- poly-line (connecting data points with straight lines)
- cubic spline
- polynomial
- linear and logarithmic calibrations (not for quantitative analysis)
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Example of a calibration curve. The calibration is a first order polynomial.
The two points at the extreme left have been excluded from the calibration (they
are marked with circles rather than dots).
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Gel Permeation Chromatography
- Calibration curves relating molecular weight to elution volume
- multi-linear
- cubic spline
- polynomial
- linear or logarithmic
- Recognising components by Mp, Mn, Mw or Mz
- Tracking molecular weight
- Molecular weight axes
- Elution volume axes
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Data Presentation
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- Data set overlaying (with or without normalising)
- Extensive peak labeling and annotation
- Fully customisable reports (including logos)
- Copying graphs to clipboard using metafiles
- Exporting data
- Several ASCII based files
- Andi (AIA) files
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Data Lists
Quick Reference Overview of Data Files
- Data Lists list numerous properties:
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- File name
- File date & time
- File type
- Data set name
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- Operator name
- Measurement time
- Number of data points
- Frequency
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- Ordinate name
- Description
- Data type
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- Sort by any property
- Search for property values
- Select all files that meet one or more search criteria
- Display component concentrations overview for all data files in list
Command Line Use
Direct analyses entirely from the command line
for very high through-put applications
For details click here
Good Laboratory Practice
- Name registration (with password login)
- Error messages and warnings are logged
- Operations on data are logged
- Preservation of raw measurement data
- File overwrite prevention
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