Problem Solver

David Hedrick

Areas David Hedrick is Knowledgeable in:

microbial ecology
analytical chemistry
methods development
experimental design

Techniques David Hedrick Uses:

Graphical analysis, factor analysis, pattern recognition, and other statistical methods are judged by results rather than theory. Spreadsheets, lists, and bibliographies are made. A thorough literature review is essential, including similar or analogous problems in other fields that have been solved. Intense study followed by long walks. Often ideas are sparked by discussion with others.

David Hedrick's Problem Solving Skills:

  1. experimental design
  2. multivariate analysis
  3. analytical chemistry
  4. ecology
  5. microbiology
  6. technical writing

David Hedrick's Problem Solving Experience:

  1. Identified several novel microbial fatty acids in environmental samples by gas chromatography-mass spectroscopy and equivalent chain length analysis, including 21 multiply-methyl branched fatty acids, 7 diacids, tetrahydrofuranyl-, and epoxy-fatty acids.
  2. Developed a method to differentiate bacteria from archaea by FTIR (Fourier-transform infra-red spectroscopy).
  3. Developed a suite of microbial lipid biomarkers for environmental studies including 2 new starvation biomarkers, 2 oxidative stress biomarkers, and methods for calculating community diversity.
  4. Derived numerical, statistically testable variables from DGGE (denaturing gradient gel electrophoresis) data. The output of the DGGE analysis is a list of the bacterial 16S rDNA sequences found in the sample, and their closest relatives found in online databases. In order to distinguish aerobic from anaerobic environments, each sequence was assigned 1 if its nearest relative was an obligate aerobe, -1 if it was an obligate anaerobe, or a 0 if it was facultative, a microaerophile, or associated with the oxygen boundary, such as methantrophs. The average of this variable over a sample is a good indicator of the aerobic or anaerobic nature of the microbial community of that sample.
  5. Invented a protocol to extract both lipids and DNA from the same environmental sample. The recovery and purity of lipid and DNA fractions was not adversely affected.
  6. Developed methods for the integrated analysis of lipid, DNA, and geochemical data from environmental samples from, for example, bioremediation projects. Issues dealt with included missing data, unreliable data, combining different data types, and increasing statistical power by transformation of data.
  7. Developed a method to determine respiratory quinones (ubiquinone, menaquinone) in environmental samples by liquid chromatography with electrochemical detection.
  8. Constructed a supercritical fluid chromatograph from equipment available for the analysis of triglycerides and archeal ether lipids.