Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Analytical Chemistry
Dna Recovery From Handwritten Documents Using A Novel Vacuum Technique, Patrick M. Mclaughlin
Dna Recovery From Handwritten Documents Using A Novel Vacuum Technique, Patrick M. Mclaughlin
Student Theses
Investigations of many crimes such as robberies, kidnappings, and terrorism are often associated with the recovery of a paper document which has been written by the perpetrator. Paper can provide a variety of forensic evidence such as DNA, latent fingermarks, and indented writing. The focus of this study was the collection of probative DNA profiles from the text region of a handwritten note through a vacuum suction device without altering or destroying the document. Collection of DNA evidence was carried out in two separate groups. The first group involved 11 volunteers providing a handwritten note sample with unwashed hands. The …
Infrared Laser Ablation For Biomolecule Sampling, Kelin Wang
Infrared Laser Ablation For Biomolecule Sampling, Kelin Wang
LSU Doctoral Dissertations
In this research, an infrared laser at a wavelength of 3 µm was used to ablate material from tissue sections for biomolecule analysis. Pulsed infrared (IR) irradiation of tissue with a focused laser beam efficiently removed biomolecules, such as proteins, enzymes, DNA, and RNA from tissue sections for further analysis. In a proteomics project, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to determine regions of interest (ROI) for laser ablation. The matrix was then washed off. By overlaying the MSI generated heat-map, the section was sampled using IR laser ablation and custom stage-control software. Two ROI were selected …
Atomic Force Microscopy Tip-Enhanced Laser Ablation, Fan Cao
Atomic Force Microscopy Tip-Enhanced Laser Ablation, Fan Cao
LSU Doctoral Dissertations
In the present work, an apertureless atomic force microscope (AFM) tip-enhanced laser ablation (TELA) system was developed and investigated. An AFM was coupled to an optical parametric oscillator (OPO) wavelength tunable laser for sample ablation with a submicron sampling size. The AFM was used to image the surface and hold the AFM tip 10 nm above the sample surface. The AFM tip is coated with a layer of gold with a thickness of 35 nm. The incident laser wavelength was tuned in the visible and near-infrared (IR) region and focused on the AFM tip. With the tip-enhancement effect, ablation craters …