Detection and identification of body fluids are crucial aspects of forensic investigations, aiding in crime scene reconstructions and providing important leads. Although many methods have been developed for these purposes, no method is currently in use in the forensic field that allows rapid, non-contact detection and identification of vaginal fluids directly at the crime scene. The development of such technique is mainly challenged by the complex chemistry of the constituents, which can differ between donors and exhibits changes based on woman’s menstrual cycle. The use of fluorescence spectroscopy has shown promise in this area for other biological fluids. Therefore, the aim of this study was to identify specific fluorescent signatures of vaginal fluid with fluorescence spectroscopy to allow on-site identification. Additionally, the fluorescent properties were monitored over time to gain insight in the temporal changes of the fluorescent spectra of vaginal fluid. The samples were excited at wavelengths ranging from 200 to 600 nm and the induced fluorescence emission was measured from 220 to 700 nm. Excitation and emission maps (EEMs) were constructed for eight donors at seven time points after donation. Four distinctive fluorescence peaks could be identified in the EEMs, indicating the presence of proteins, fluorescent oxidation products (FOX), and an unidentified component as the dominant contributors to the fluorescence. To further asses the fluorescence characteristics of vaginal fluid, the fluorescent signatures of protein and FOX were used to monitor protein and lipid oxidation reactions over time. The results of this study provide insights into the intrinsic fluorescent properties of vaginal fluid over time which could be used for the development of a detection and identification method for vaginal fluids. Furthermore, the observed changes in fluorescence signatures over time could be utilized to establish an accurate ageing model.
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Non-invasive, rapid, on-site detection and identification of body fluids is highly desired in forensic investigations. The use of fluorescence-based methods for body fluid identification, have so far remain relatively unexplored. As such, the fluorescent properties of semen, serum, urine, saliva and fingermarks over time were investigated, by means of fluorescence spectroscopy, to identify specific fluorescent signatures for body fluid identification. The samples were excited at 81 different excitation wavelengths ranging from 200 to 600 nm and for each excitation wavelength the emission was recorded between 220 and 700 nm. Subsequently, the total emitted fluorescence intensities of specific fluorescent signatures in the UV–visible range were summed and principal component analysis was performed to cluster the body fluids. Three combinations of four principal components allowed specific clustering of the body fluids, except for fingermarks. Blind testing showed that 71.4% of the unknown samples could be correctly identified. This pilot study shows that the fluorescent behavior of ageing body fluids can be used as a new non-invasive tool for body fluid identification, which can improve the current guidelines for the detection of body fluids in forensic practice and provide the robustness of methods that rely on fluorescence.
MULTIFILE
Semen traces are considered important pieces of evidence in forensic investigations, especially those involving sexsual offenses. Recently, our research group developed a fluorescence-based technique to accurately determine the age of semen traces. However, the specific compounds resonsible for the fluoresescent behaviour of ageing semens remain unknown. As such, in this exploratory study, the aim is to identify the components associated with the fluorescent behavior of ageing semen traces. In this investigation semen stains and various biofluorophores commonly found in body fluids were left to aged for 0, 2, 4, 7, 14 and 21 days. Subsequently, thin-layer chromatography (TLC) and ultra-performance liquid chromatography (UPLC) mass spectrometry were performed to identify the biofluorophores present in semen. Several contributors to the autofluorescence could be identified in semen stain, these include tryptophan, kynurenine, kynurenic acid, and norharman. The study sheds light on the.
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Net als in het boek van Dan Brown, de ‘Da Vinci Code’, is de politie altijd op zoek naar aanwijzingen die naar de dader kunnen leiden. Waar in het boek allerlei cryptische symbolen en codes verborgen achtergelaten worden als aanwijzingen, zal in de praktijk bij forensisch onderzoek van de politie of het NFI, sporen gevonden moeten worden op een plaats delict. Het onderwerp van dit projectvoorstel, DaVinciQD, ligt op het dateren van een van dat soort sporen, namelijk vingersporen. Er wordt standaard in forensisch onderzoek naar vingersporen gezocht en indien gedetecteerd en veiliggesteld, worden zij ter plaatse of in het forensisch lab onderzocht en vervolgens vergeleken met een grote databank. Relevant is het om te bepalen of een vingerspoor afkomstig is van de dader en dus relevant voor het forensisch onderzoek. Om dit te bepalen is het niet alleen noodzakelijk om een vingerafdruk zichtbaar te maken en te koppelen aan een persoon, maar ook om deze te kunnen relateren aan het tijdsframe van het gepleegde misdrijf. Daarom de vraag om een methode te ontwikkelen die in staat is om vingerafdrukken te dateren. Het bepalen van het moment van achterlaten van een vingerspoor is cruciaal enerzijds om te bepalen of deze relevant is voor het lopende onderzoek, maar ook in de context van bewijsvoering en een eventuele veroordeling van een dader. Een consortium bestaande uit de onderzoeksgroepen Advanced Forensic Technology en NanoBio van Saxion, het Nederlands Forensisch Instituut, de Nationale Politie, de Universiteit Twente en enkele private bedrijven, zal een methode ontwikkelen om met behulp van quantum dots de datering van vingersporen mogelijk maken. De methode zal niet alleen in het lab, maar ook in de praktijk van de forensisch onderzoeker getest en gevalideerd worden.
Structural colour (SC) is created by light interacting with regular nanostructures in angle-dependent ways resulting in vivid hues. This form of intense colouration offers commercial and industrial benefits over dyes and other pigments. Advantages include durability, efficient use of light, anti-fade properties and the potential to be created from low cost materials (e.g. cellulose fibres). SC is widely found in nature, examples include butterflies, squid, beetles, plants and even bacteria. Flavobacterium IR1 is a Gram-negative, gliding bacterium isolated from Rotterdam harbour. IR1 is able to rapidly self-assemble into a 2D photonic crystal (a form of SC) on hydrated surfaces. Colonies of IR1 are able to display intense, angle-dependent colours when illuminated with white light. The process of assembly from a disordered structure to intense hues, that reflect the ordering of the cells, is possible within 10-20 minutes. This bacterium can be stored long-term by freeze drying and then rapidly activated by hydration. We see these properties as suiting a cellular reporter system quite distinct from those on the market, SC is intended to be “the new Green Fluorescent Protein”. The ability to understand the genomics and genetics of SC is the unique selling point to be exploited in product development. We propose exploiting SC in IR1 to create microbial biosensors to detect, in the first instance, volatile compounds that are damaging to health and the environment over the long term. Examples include petroleum or plastic derivatives that cause cancer, birth defects and allergies, indicate explosives or other insidious hazards. Hoekmine, working with staff and students within the Hogeschool Utrecht and iLab, has developed the tools to do these tasks. We intend to create a freeze-dried disposable product (disposables) that, when rehydrated, allow IR1 strains to sense and report multiple hazardous vapours alerting industries and individuals to threats. The data, visible as brightly coloured patches of bacteria, will be captured and quantified by mobile phone creating a system that can be used in any location by any user without prior training. Access to advice, assay results and other information will be via a custom designed APP. This work will be performed in parallel with the creation of a business plan and market/IP investigation to prepare the ground for seed investment. The vision is to make a widely usable series of tests to allow robust environmental monitoring for all to improve the quality of life. In the future, this technology will be applied to other areas of diagnostics.
Resistance to damage, fracture and failure is critical for high performance polymers, especially so in safety applications where they protect equipment or human life. In this project we investigate the use of molecular mechanochemistry tools for the measurement and analysis of mechanical impact in high performance polymers and their composites. While typically performed in a laboratory setting, these measurements hold promise for studying damage in large scale realistic samples. For this we will to develop fluorescent imaging techniques and chemistry, necessary to produce mechanoresponsive samples. This proposal will also draw correlations between imaging and mechanical testing, which can ultimately allow us to study realistic samples and recover the history of the impact they have sustained during operation.
