Forensic Screening
Forensic Screening - Related Videos
11:49
Enhanced Genetic Analysis of Single Human Bioparticles Recovered by Simplified Micromanipulation from Forensic ‘Touch DNA’ Evidence
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Cited by 26 •
2015
Here we describe an optimized and efficient removal strategy for the collection of bio-particles present in ‘touch DNA’ samples, together with an enhanced amplification protocol involving a one-step 5 µl micro-volume lysis/STR amplification, to permit the recovery of short tandem repeat (STR) profiles of the bio-particle donor(s).
05:31
Gas Chromatography-Mass Spectrometry Paired with Total Vaporization Solid-Phase Microextraction as a Forensic Tool
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Cited by 2 •
2021
Total Vaporization Solid Phase Microextraction (TV-SPME) completely vaporizes a liquid sample whilst analytes are sorbed onto a SPME fiber. This allows for partitioning of the analyte between only the solvent vapor and the SPME fiber coating.
07:56
Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts
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Cited by 13 •
2018
Bone mineral density (BMD) is an important factor in understanding nutritional intake. For human skeletal remains, it is a useful metric to assess quality of life in both juveniles and adults, particularly in fatal starvation and neglect cases. This paper provides guidelines for scanning human skeletal remains for forensic purposes.
09:44
High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
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2015
Here we describe a cell-based reporter gene assay as a valuable tool to screen chemical libraries for compounds modulating post-transcriptional control mechanisms exerted through 3’ UTR.
08:50
Genetic Screens
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2023
Genetic screens are critical tools for defining gene function and understanding gene interactions. Screens typically involve mutating genes and then assessing the affected organisms for phenotypes of interest. The process can be “forward”, where mutations are generated randomly to identify unknown genes responsible for the phenotypes, or it can be “reverse”, where specific genes are targeted for mutation to observe what phenotypes are produced.Here, JoVE reviews various types of genetic...
FAQs
These reactions convert a possible substance-related interaction into an observable signal. A color change or fluorescence can indicate a reaction product, while precipitation or selective binding can reveal interaction with a target substance. Because different evidence types may produce different responses, the selected reaction helps investigators rapidly identify samples that warrant more detailed chemical examination.
Controls provide a comparison for deciding whether an observed signal is meaningful. They help distinguish a reaction associated with the evidence from an unreliable or uninterpretable result. In practice, screening findings should be considered alongside the appropriate controls rather than treated as isolated observations, improving the basis for prioritizing samples for confirmatory analysis.
A presumptive reaction indicates that a sample may contain a relevant substance, but it does not by itself provide definitive identification. Similar chemical responses can limit the specificity of a rapid test. For that reason, a positive result guides further examination, while confirmatory methods are needed before investigators draw stronger conclusions about the substance present.
Screening methods provide rapid preliminary indications through observable chemical responses, making them useful for selecting evidence for additional work. Chromatography, spectroscopy, and mass spectrometry serve as confirmatory approaches in the described workflow. The distinction is therefore not simply speed, but the evidentiary role: screening directs attention, whereas confirmatory analysis supports more definitive chemical identification.
A typical workflow begins by applying a suitable rapid chemical test to biological, material, or trace evidence and observing the resulting signal. Investigators interpret that response with appropriate controls, then prioritize samples that require additional examination. Confirmatory analysis can follow using chromatography, spectroscopy, or mass spectrometry, depending on the evidence and investigative need.
The approach can support preliminary examination of biological evidence, materials, and trace evidence. Reported applications include possible detection of drugs, toxins, blood, explosives, and other residues. These uses help laboratories decide which samples deserve confirmatory attention and can guide subsequent forensic investigation without treating the initial screening response as a final identification.
Chemistry supplies the reactions and observations that connect an evidence sample with a possible substance of investigative interest. Signals such as color, fluorescence, precipitation, or selective binding provide an efficient basis for triage. In a forensic workflow, this chemical information helps organize evidence processing and directs later analyses toward the most informative samples.