Drosophila melanogaster odorant receptors as volatile compound detectors in forensic science: a proof-of-concept study.

The ability to detect and identify substances based on the volatile compounds (odors) they emit is relied upon heavily for numerous investigative purposes. Animals have an innate olfactory sensitivity and selectivity that out-performs current instrumentation. This has led to immense interest in their employment as chemical sensors for a range of applications, including forensic science, both as whole organisms and as sensing elements in biosensors. Using electrophysiological and calcium imaging assays, this research examined the response of Drosophila melanogaster olfactory receptors (ORs) to odor compounds significant in forensic science and assessed their potential utility as volatile compound sensors. This investigation illustrated the different sensitivities, selectivities, and sensing features of individual ORs and demonstrated that their employment for detection purposes is feasible. While further research expanding on this study will be required to demonstrate the performance characteristics that an OR-based detection system will ultimately possess, this research provides an encouraging first step towards the goal of utilizing isolated biological ORs as volatile compound sensors in forensic science.

Best interest versus advance decisions to refuse treatment in advance care planning for neurodegenerative illness.

This article describes the role of nurses assisting people with degenerative illness in advance care planning (ACP) for a time when they may lose decision-making capacity. It looks at the concept of advance decisions to refuse treatment (ADRT), as defined in the Mental Capacity Act 2005 , exploring the legal, ethical and philosophical ramifications of carrying out, or overriding, formerly expressed wishes of someone who has subsequently lost decision-making capacity. It uses an illustrative composite case study of an individual with Huntington's disease whose prognosis includes future deterioration in swallowing, together with consideration of whether to have or refuse a percutaneous endoscopic gastrostomy. The author, who as part of his role cares for people with neurodegenerative conditions, including Huntington's disease, discusses the difficulties and dilemmas that nurses experience with ADRTs, drawing on personal experience. He suggests that, rather than focusing on ADRTs, ACP may be most effective in preparing people and their surrogates to make real-time decisions, based on a shared understanding of the individual's values.

Chemosensory genes identified in the antennal transcriptome of the blowfly Calliphora stygia.

BACKGROUND: Blowflies have relevance in areas of forensic science, agriculture, and medicine, primarily due to the ability of their larvae to develop on flesh. While it is widely accepted that blowflies rely heavily on olfaction for identifying and locating hosts, there is limited research regarding the underlying molecular mechanisms. Using next generation sequencing (Illumina), this research examined the antennal transcriptome of Calliphora stygia (Fabricius) (Diptera: Calliphoridae) to identify members of the major chemosensory gene families necessary for olfaction. RESULTS: Representative proteins from all chemosensory gene families essential in insect olfaction were identified in the antennae of the blowfly C. stygia, including 50 odorant receptors, 22 ionotropic receptors, 21 gustatory receptors, 28 odorant binding proteins, 4 chemosensory proteins, and 3 sensory neuron membrane proteins. A total of 97 candidate cytochrome P450s and 39 esterases, some of which may act as odorant degrading enzymes, were also identified. Importantly, co-receptors necessary for the proper function of ligand-binding receptors were identified. Putative orthologues for the conserved antennal ionotropic receptors and candidate gustatory receptors for carbon dioxide detection were also amongst the identified proteins. CONCLUSIONS: This research provides a comprehensive novel resource that will be fundamental for future studies regarding blowfly olfaction. Such information presents potential benefits to the forensic, pest control, and medical areas, and could assist in the understanding of insecticide resistance and targeted control through cross-species comparisons.

Portable gas chromatography-mass spectrometry method for the in-field screening of organic pollutants in soil and water at pollution incidents.

Environmental pollution incidents generate an emergency response from regulatory agencies to ensure that the impact on the environment is minimised. Knowing what pollutants are present provides important intelligence to assist in determining how to respond to the incident. However, responders are limited in their in-field capabilities to identify the pollutants present. This research has developed an in-field, qualitative analytical approach to detect and identify organic pollutants that are commonly detected by regulatory environmental laboratories. A rapid, in-field extraction method was used for water and soil matrices. A coiled microextraction (CME) device was utilised for the introduction of the extracted samples into a portable gas chromatography-mass spectrometry (GC-MS) for analysis. The total combined extraction and analysis time was approximately 6.5 min per sample. Results demonstrated that the in-field extraction and analysis methods can screen for fifty-nine target organic contaminants, including polyaromatic hydrocarbons, monoaromatic hydrocarbons, phenols, phthalates, organophosphorus pesticides, and organochlorine pesticides. The method was also capable of tentatively identifying unknown compounds using library searches, significantly expanding the scope of the methods for the provision of intelligence at pollution incidents of an unknown nature, although a laboratory-based method was able to provide more information due to the higher sensitivity achievable. The methods were evaluated using authentic casework samples and were found to be fit-for-purpose for providing rapid in-field intelligence at pollution incidents. The fact that the in-field methods target the same compounds as the laboratory-based methods provides the added benefit that the in-field results can assist in sample triaging upon submission to the laboratory for quantitation and confirmatory analysis.

Latent fingermark detection using functionalised silicon oxide nanoparticles: Investigation into novel application procedures.

Investigations into the application of carboxyl-functionalised silicon oxide nanoparticles doped with a ruthenium complex (RuBpy-doped CES-SiO2 NPs) for latent fingermark development on non-porous surfaces were reported in previous studies. These studies suggested that an optimised NP-based method demonstrated advantages in fingermark selectivity and sensitivity. To continue the series of research into using RuBpy-doped CES-SiO2 NPs for fingermark detection, the versatility and overall practicality of the optimised SiO2 NP-based reagent for latent fingermark detection and enhancement was evaluated. When the optimised NP-based method was used in a repeated fashion (application of multiple NP treatment cycles), it was found that the overall fingermark detection quality increased across the evaluated fingermarks without a high risk of overdevelopment. The possibility of incorporating the optimised NP-based reagent for potential operational use (e.g., at crime scenes) was successfully demonstrated via spray application on three test surfaces (aluminium foil, transparent polypropylene film and green polyethylene film). It was also shown that further enhancement of "spray-detected" fingermarks was achievable via subsequent treatment using the NP-based reagent in a colloidal dispersion bath. Additionally, the compatibility of the optimised NP-based method with two-step cyanoacrylate fuming for latent fingermark detection was evaluated. It was concluded that the two techniques are not compatible for application in a fingermark detection sequence. While encouraging results were demonstrated in this study, further optimisation and comparison will be required before the multiple-treatment and spray-treatment approaches can be considered for operational implementation.

The Sydney declaration - Revisiting the essence of forensic science through its fundamental principles.

Unlike other more established disciplines, a shared understanding and broad acceptance of the essence of forensic science, its purpose, and fundamental principles are still missing or mis-represented. This foundation has been overlooked, although recognised by many forensic science forefathers and seen as critical to this discipline's advancement. The Sydney Declaration attempts to revisit the essence of forensic science through its foundational basis, beyond organisations, technicalities or protocols. It comprises a definition of forensic science and seven fundamental principles that emphasise the pivotal role of the trace as a vestige, or remnant, of an investigated activity. The Sydney Declaration also discusses critical features framing the forensic scientist's work, such as context, time asymmetry, the continuum of uncertainties, broad scientific knowledge, ethics, critical thinking, and logical reasoning. It is argued that the proposed principles should underpin the practice of forensic science and guide education and research directions. Ultimately, they will benefit forensic science as a whole to be more relevant, effective and reliable.

Fingermark detection using upconverting nanoparticles and comparison with cyanoacrylate fuming.

This paper reports the synthesis of high-quality upconverting nanoparticles (UCNPs) - sodium yttrium tetrafluoride doped with ytterbium and erbium (NaYF4:Yb,Er) with a silica shell and capped with phenyl functional groups. The main goal of this research was to design tailor-made UCNPs for fingermark detection, to test and validate a nanoparticle-based detection technique and to compare their performance against a benchmark method to assess potential implementation in routine practice by law enforcement agencies. The water-based UCNPs solution was applied to natural fingermarks on a number of substrates. This is the first ever systematic comparative study between UCNPs and a benchmark fingermark detection technique - cyanoacrylate fuming (CAF) followed by luminescent dye staining. Fingermark detection effectiveness was studied by treating 300 latent fingermark specimens on aluminium foil, polyethylene, polypropylene and glass slides. It was concluded that, on average, CAF performed better across the substrates tested. Nevertheless, UCNPs can be advantageous for fingermark detection on multicoloured, patterned or luminescent substrates due to their unique optical properties. There are, however, shortfalls associated with their synthesis and use that need to be addressed before they can be considered for operational purposes.

Application of a Microfluidic Gas-to-Liquid Interface for Extraction of Target Amphetamines and Precursors from Air Samples.

The investigation of clandestine laboratories poses serious hazards for first responders, emergency services, investigators and the surrounding public due to the risk of exposure to volatile organic compounds (VOCs) used in the manufacture of illicit substances. A novel gas sampling interface using open microfluidic channels that enables the extraction of VOCs out of the gas phase and into a liquid, where it can be analysed by conventional detection systems, has recently been developed. This paper investigates the efficiency and effectiveness of such a gas-to-liquid (GTL) extraction system for the extraction of amphetamine-type substances (ATS) and their precursors from the vapour phase. The GTL interface was evaluated across a range of different ATS and their precursors (methamphetamine, dimethylamphetamine, N-formylmethamphetamine, benzaldehyde, phenyl-2-propanone, ephedrine and pseudoephedrine) at concentrations ranging between 10 and 32 mg m-3. These gas samples were produced by a gas generation system directly in Tedlar® bags and gas canisters for controlled volume sampling. When using gas sampled from Tedlar® bags, four of the seven compounds were able to be extracted by the GTL interface, with the majority of the VOCs having extraction yields between 0.005% and 4.5%, in line with the results from an initial study. When samples were taken from gas canisters, only benzaldehyde was able to be detected, with extraction efficiencies between 0.2% and 0.4%. A custom-built mount for the GTL interface helped to automate the extraction process, with the aim of increasing extraction efficiency or reducing variability. However, the extraction efficiency did not improve when using this accessory, but the procedure did become more efficient. The results from the study indicated that the GTL interface could be employed for the collection of gaseous ATS and incorporated into mobile detection systems for onsite collection and analysis of volatile compounds related to ATS manufacture.

Rapid on-site identification of hazardous organic compounds at fire scenes using person-portable gas chromatography-mass spectrometry (GC-MS)-part 1: air sampling and analysis.

Recent advancements in person-portable instrumentation have resulted in the potential to provide contemporaneous results through rapid in-field analyses. These technologies can be utilised in emergency response scenarios to aid first responders in appropriate site risk assessment and management. Large metropolitan fires can pose great risk to human and environmental health due to the rapid release of hazardous compounds into the atmosphere. Understanding the release of these hazardous organics is critical in understanding their associated risks. Person-portable gas chromatography-mass spectrometry (GC-MS) was evaluated for its potential to provide rapid on-site analysis for real-time monitoring of hazardous organic compounds at fire scenes. Air sampling and analysis methods were developed for scenes of this nature. Controlled field testing demonstrated that the portable GC-MS was able to provide preliminary analytical results on the volatile organic compounds present in air samples collected from both active and extinguished fires. In-field results were confirmed using conventional laboratory-based air sampling and analysis procedures. The deployment of portable instrumentation could provide first responders with a rapid on-site assessment tool for the appropriate management of scenes, thereby ensuring environmental and human health is proactively protected and scientifically informed decisions are made for the provision of timely advice to stakeholders.

Rapid on-site identification of hazardous organic compounds at fire scenes using person-portable gas chromatography-mass spectrometry (GC-MS)-part 2: water sampling and analysis.

Building and factory fires pose a great risk to human and environmental health, due to the release of hazardous by-products of combustion. These hazardous compounds can dissipate into the environment through fire water run-off, and the impact can be immediate or chronic. Current laboratory-based methods do not report hazardous compounds released from a fire scene at the time and location of the event. Reporting of results is often delayed due to the complexities and logistics of laboratory-based sampling and analysis. These delays pose a risk to the health and wellbeing of the environment and exposed community. Recent developments in person-portable instrumentation have the potential to provide rapid analysis of samples in the field. A portable gas chromatograph-mass spectrometer (GC-MS) was evaluated for the on-site analysis of water samples for the identification of hazardous organic compounds at fire scenes. The portable GC-MS was capable of detecting and identifying a range of volatile and semi-volatile organic compounds in fire water run-off, and can be used in conjunction with conventional laboratory analysis methods for a comprehensive understanding of hazardous organics released at fire scenes. Deployment of this portable instrumentation provides first responders with a rapid, on-site screening tool to appropriately manage the run-off water from firefighting activities. This ensures that environmental and human health is proactively protected.

Latent fingermark detection using functionalised silicon oxide nanoparticles: Optimisation and comparison with cyanoacrylate fuming.

Among the different types of nanoparticles (NPs) proposed for fingermark detection, silicon oxide nanoparticles (SiO2 NPs) are arguably the most promising due to their unique characteristics. In this study, carboxyl-functionalised SiO2 NPs doped with luminescent ruthenium complex-RuBpy-doped CES-SiO2 NPs-were further studied to investigate their effectiveness for latent fingermark detection. A modified version of the functionalised SiO2 NPs with a lower amount of surface functionalisation is proposed for improved fingermark detection effectiveness. A shaking incubator was also incorporated into the fingermark detection process to offer a more viable treatment approach in comparison to the previously published method. The shaking incubator offered a more robust application approach, as well as improved fingermark detection quality. To gain an insight into fingermark detection effectiveness relative to benchmark techniques, the performance of the optimised RuBpy-doped CES-SiO2 NPs was compared to that of a benchmark fingermark detection method-cyanoacrylate fuming (CAF) followed by luminescent dye staining. Relative fingermark detection effectiveness across the two techniques was evaluated via the treatment of 1724 fingermark specimens. It was concluded that, in general, the benchmark method provided superior detection results. It was evident that the SiO2 NPs are less affected by donor variability but are more dependent on substrate types. Such characteristics are encouraging as they could be favourable to practitioners in casework scenarios where the substrate is known but donor variability is obscure prior to fingermark processing. It should be noted that the overall effectiveness of the proposed NP-based technique will need to be improved before it could be considered for operational implementation.

Single metal deposition versus physical developer: A comparison between two advanced fingermark detection techniques.

Single metal deposition (SMD II) is a fingermark detection technique based on the use of colloidal gold. The technique has been simplified and optimised over the years to become more reliable, sensitive and user-friendly. Physical developer (PD) is a well-established detection method based on silver deposition from a redox solution. This study presents an extensive comparison of SMD II against PD for fingermark detection on porous substrates. The two techniques were compared as (i) standalone methods, (ii) in sequence after the application of routine amino acids reagents (1,2-indanedione/zinc followed by ninhydrin), and (iii) after the substrates have been wet. More than 1000 fingermark specimens were processed. Overall, the performance of SMD II was judged to be inferior to that of PD; therefore, SMD II cannot be recommended as a valid replacement for fingermark detection on porous substrates. Indanedione/zinc and ninhydrin application negatively impacts on SMD II performance and the technique gave inconsistent results across the selected range of porous substrates. Moreover, the detected fingermarks lacked contrast making their visualisation difficult. However, even if PD remains the technique of choice, SMD II showed significant potential. It proved to be less affected by donor variability and it can be applied on both porous and non-porous substrates. It did not lead to uncontrolled background staining that commonly occurs with PD. If contrast and consistency issues can be addressed in future research, SMD II may become a viable alternative to PD.

Latent fingermark detection using functionalised silicon oxide nanoparticles: Method optimisation and evaluation.

The application of nanoparticles for latent fingermark detection has been reported in the literature over the past two decades. One of the nanoparticles that shows promise to become a routine technique is functionalised silicon oxide nanoparticles (SiO2 NPs). In a recent optimisation of the technique, the use of carboxyl-functionalised SiO2 NPs doped with luminescent ruthenium complex was proposed as a breakthrough for latent fingermark detection. In this study, the aforementioned functionalised SiO2 NPs were extensively evaluated. Modification and optimisation of the original detection parameters were performed to enhance detection quality and improve applicability. Various detection parameters were evaluated and assessed. A lower concentration of the functionalised nanoparticles used in the colloidal dispersion was determined to offer improved detection effectiveness. A combination of increased bath temperature and reduced immersion time was found to produce good overall results. A set of modified detection parameters was suggested for the use of the functionalised SiO2 NPs to detect latent fingermarks. Performance of the modified detection parameters was compared against that of the published detection method. Comparison experiments were carried out on fingermark specimens deposited on aluminium foil, transparent polypropylene plastic and green polyethylene plastic. Three donors (weak, average and strong) and two age intervals (ten days and three months) were considered in the comparison study. Evaluation of the results suggested that the overall performance of the modified method for latent fingermark detection was superior to that obtained using the previously published detection parameters.

Identification of inorganic ions in post-blast explosive residues using portable CE instrumentation and capacitively coupled contactless conductivity detection.

Novel CE methods have been developed on portable instrumentation adapted to accommodate a capacitively coupled contactless conductivity detector for the separation and sensitive detection of inorganic anions and cations in post-blast explosive residues from homemade inorganic explosive devices. The methods presented combine sensitivity and speed of analysis for the wide range of inorganic ions used in this study. Separate methods were employed for the separation of anions and cations. The anion separation method utilised a low conductivity 70 mM Tris/70 mM CHES aqueous electrolyte (pH 8.6) with a 90 cm capillary coated with hexadimethrine bromide to reverse the EOF. Fifteen anions could be baseline separated in 7 min with detection limits in the range 27-240 microg/L. A selection of ten anions deemed most important in this application could be separated in 45 s on a shorter capillary (30.6 cm) using the same electrolyte. The cation separation method was performed on a 73 cm length of fused-silica capillary using an electrolyte system composed of 10 mM histidine and 50 mM acetic acid, at pH 4.2. The addition of the complexants, 1 mM hydroxyisobutyric acid and 0.7 mM 18-crown-6 ether, enhanced selectivity and allowed the separation of eleven inorganic cations in under 7 min with detection limits in the range 31-240 microg/L. The developed methods were successfully field tested on post-blast residues obtained from the controlled detonation of homemade explosive devices. Results were verified using ion chromatographic analyses of the same samples.

Lawsone: a novel reagent for the detection of latent fingermarks on paper surfaces.

Lawsone (2-hydroxy-1,4-naphthoquinone) reacts with latent fingermark deposits on paper surfaces to yield purple-brown impressions of ridge details which are also photoluminescent; this compound represents the first in a completely new class of fingermark detection reagents.

A Systems Approach to Biometrics in the Military Domain.

Forensic biometrics is the application of forensic science principles to physical and behavioral characteristics. Forensic biometrics is a secondary sub-system in the forensic science "system of systems," which describes forensic science as a sub-system in the larger criminal justice, law enforcement, intelligence, and military system. The purpose of this paper is to discuss biometrics in the military domain and integration into the wider forensic science system of systems. The holistic system thinking methodology was applied to the U.S. biometric system to map it to the system of systems framework. The U.S. biometric system is used as a case study to help guide other countries to develop military biometric systems that are integrated and interoperable at the whole-of-government level. The aim is to provide the system of systems framework for agencies to consider for proactive design of biometric systems.

Fit for purpose quality management system for military forensic exploitation.

In a previous publication we described a systems approach to forensic science applied in the military domain. The forensic science 'system of systems' describes forensic science as a sub-system in the larger criminal justice, law enforcement, intelligence, and military systems, with quality management being an important supporting system. Quality management systems help to ensure that organisations achieve their objective and continually improve their capability. Components of forensic science quality management systems can include standardisation of processes, accreditation of facilities to national/international standards, and certification of personnel. A fit for purpose quality management system should be balanced to allow organisations to meet objectives, provide continuous improvement; mitigate risk; and impart a positive quality culture. Considerable attention over the last decades has been given to the need for forensic science quality management systems to meet criminal justice and law enforcement objectives. More recently, the need for the forensic quality management systems to meet forensic intelligence objectives has been considered. This paper, for the first time, discusses the need for a fit for purpose quality management system for military forensic exploitation.

Investigation of some of the factors influencing fingermark detection.

The primary aims of fingermark detection research are to improve the quality and increase the rate of detection of identifiable impressions. This is usually performed through the development of new methods and technologies to provide alternatives to or improve current procedures. While research of this nature is important to pursue, it fails to address the underlying question related to the factors that affect the detection of a latent fingermark. There has been significant research that has examined the differences between techniques, donors and fingermark age, as well as the composition of latent fingermarks. However, they tend not to focus on determining how these factors influence the quality of the developed mark. This study involved the development and evaluation of over 14,000 natural fingermarks deposited on a variety of surfaces to examine the effect of substrate, age, donor variability (both inter- and intra-), depletions and type of finger on fingermark development. Fingermarks were deposited on four substrates (two non-porous and two porous) and developed with either indanedione-zinc (IND-Zn) or cyanoacrylate followed by rhodamine 6G staining (CA+R6G). Three independent assessors graded each mark on the quality of development using an absolute scale proposed by the UK Centre for Applied Science and Technology (CAST). The data generated from these assessments were then analysed for trends or other useful insights. The results from this work reaffirm that individual substrate characteristics (and the choice of development technique) play a significant role in determining the number and quality of marks developed. It was found that fingermarks were more likely to be detected on porous substrates and to also be of a higher quality than on non-porous. The effect of fingermark donor variability was also explored, with significant differences observed between donors and within donors. This research shows that current detection techniques do not detect all available fingermarks, reinforcing the need for further research into the fundamentals of fingermark detection in order to gain a better understanding of the techniques currently used. The study has identified considerations for the development of novel techniques and how we need to account for variability when designing fingermark research experiments.

Metal-Organic Frameworks for fingermark detection - A feasibility study.

Metal-Organic Frameworks (MOFs) are porous crystalline structures, currently used as sensors, separation membranes, and as catalysts. Due to their physicochemical and optical properties, they have been recently proposed for fingermark detection. This study further explored their potential for fingermark detection. Natural fingermarks, as well as charged and protein-enriched marks, were used to test the efficiency of the technique. Various parameters, such as precursor concentration, pH, immersion time and detection protocols, were investigated and optimised. The performance of the optimised MOF-based method was then compared to that of routinely used techniques. The results obtained indicated that MOFs can effectively detect fingermarks, especially protein-rich marks such as marks contaminated with body fluids. However, after comparison and evaluation against benchmark techniques, results were judged to be inferior to those from currently employed detection methods. However, with further research and optimisation MOFs may be promising as an alternative to current powder suspension techniques.

Applying visible hyperspectral (chemical) imaging to estimate the age of bruises.

Hyperspectral (chemical) imaging collects spectroscopic data in a two-dimensional spatial format. The potential application for the determination of the age of bruises is demonstrated and compared to reflectance probe spectrophotometry as well as photography. Blood was deposited on white cotton cloth or injected subcutaneously into pig skin to simulate a 'fresh bruise'. A mixture of blood and bile was used to simulate 'old' bruises. On the cloth background all the photographic methods clearly separated the two groups of samples (i.e. 'blood only' from 'blood plus bile'). However, on the pig skin the two groups could be separated by one of the photographic methods only. Separation of blood from blood and bile mixtures was obtained on the cloth and skin backgrounds using spectrophotometry and hyperspectral imaging. In a test using serial dilutions of blood and bile mixtures, the hyperspectral system performed slightly better than the spectrophotometer. The former also had the advantage of imaging a wider area and providing spatial data. Hyperspectral (chemical) imaging and spectrophotometry are superior to photography for the detection of bilirubin on a background of skin (due to the presence of yellow chromophores); this technology combined with mathematical analysis of the spectral data warrants further investigation.