Agapios Agapiou

Combined chemical and optical methods for monitoring the early decay stages of surrogate human models.

As the body decays shortly after death, a variety of gases and volatile organic compounds (VOCs) constantly emanate. Ethical and practical reasons limit the use of human corpses in controlled, time-dependent, intervening experiments for monitoring the chemistry of body decay. Therefore the utilization of pig carcasses serves as a potential surrogate to human models. The aim of this work was to study buried body decay in conditions of entrapment in collapsed buildings. Six domestic pigs were used to study carcass decay. They were enclosed in plastic body bags after being partially buried with rubbles, resembling entrapment in collapsed buildings. Three experimental cycles were performed, employing two pig carcasses in each cycle; VOCs and inorganic gases were measured daily, along with daily visible and thermal images. VOCs were collected in standard sorbent tubes and subsequently analyzed using a Thermal Desorption/Gas Chromatograph/high sensitivity bench-top Time-of-Flight Mass Spectrometer (TD/GC/TOF-MS). A comprehensive, stage by stage, detailed information on the decay process is being presented based on the experimental macroscopic observations, justifying thus the use of pig carcasses as surrogate material. A variety of VOCs were identified including almost all chemical classes: sulfur, nitrogen, oxygen compounds (aldehydes, alcohols, ketones, acids and esters), hydrocarbons, fluorides and chlorides. Carcasses obtained from a pig farm resulted in more sulfur and nitrogen cadaveric volatiles. Carbon dioxide was by far the most abundant inorganic gas identified along with carbon monoxide, hydrogen sulfide and sulfur dioxide. Visual monitoring was based on video captured images allowing for macroscopic observations, while thermal camera monitoring which is mostly temperature dependent, resulted in highlighting the local micro-changes on the carcasses, as a result of the intense microbial activity. The combination of chemical and optical methods proved very useful and informative, uncovering hidden aspects of the early stages of decay and also guiding in the development of combined chemical and imaging methods for the detection of dead bodies.

Application of ion mobility spectrometry for the detection of human urine

The aim of the present study was to evaluate the suitability of ion mobility spectrometry (IMS) for the detection of human urine as an indication of human presence during urban search and rescue operations in collapsed buildings. To this end, IMS with a radioactive ionization source and a multicapillary column was used to detect volatile organic compounds (VOCs) emitted from human urine. A study involving a group of 30 healthy volunteers resulted in the selection of seven volatile species, namely acetone, propanal, 3-methyl-2-butanone, 2-methylpropanal, 4-heptanone, 2-heptanone and octanal, which were detected in all samples. Additionally, a preliminary study on the permeation of urine volatiles through the materials surrounding the voids of collapsed buildings was performed. In this study, quartz sand was used as a representative imitating material. Four compounds, namely 3-methyl-2-butanone, octanal, acetone and 2-heptanone, were found to permeate through the sand layers during all experiments. Moreover, their permeation times were the shortest. Although IMS can be considered as a potential technique suitable for the detection, localization and monitoring of VOCs evolved from human urine, further investigation is necessary prior to selecting field chemical methods for the early location of trapped victims.

Temporal profiling of human urine VOCs and its potential role under the ruins of collapsed buildings

Context: The scent profile of human urine was investigated as potential source of chemical markers of human presence in collapsed buildings after natural or man-made disasters. Objective: The main goals of this study were to build a library of potential biomarkers of human urine to be used for the detection of entrapped victims and to further examine their evolution profile in time. Materials and methods: Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to detect and identify the volatile organic compounds (VOCs) spontaneously released from urine of 20 healthy volunteers. Additionally, the evolution of human urine headspace during four days storage at room temperature was investigated. Results: 33 omnipresent species with incidence higher than 80% were selected as potential urine markers. The most represented chemical classes were ketones with 10 representatives, aldehydes (7 species) and sulfur compounds (7 species). The monitoring of the evolution of the urine scent demonstrated an increase in the emission of 26 omnipresent urinary volatiles (rise from 36% to 526%). The highest increase was noted for dimethyldisulfide and dimethyltrisulfide (fivefold increase) and 3-methyl-2-butanone, 4-methyl-2-pentanone and 3-hexanone (fourfold rise). Only three compounds exhibited decreasing trend; dimethylsulfone, octanal and propanal. Conclusion: The ubiquitous urine VOCs identified within this study create a library of potential markers of human urine to be verified in further field studies, involving portable and sensitive instruments, directly applied in the field.

The trapped human experiment

This experiment observed the evolution of metabolite plumes from a human trapped in a simulation of a collapsed building. Ten participants took it in turns over five days to lie in a simulation of a collapsed building and eight of them completed the 6 h protocol while their breath, sweat and skin metabolites were passed through a simulation of a collapsed glass-clad reinforced-concrete building. Safety, welfare and environmental parameters were monitored continuously, and active adsorbent sampling for thermal desorption GC-MS, on-line and embedded CO, CO(2) and O(2) monitoring, aspirating ion mobility spectrometry with integrated semiconductor gas sensors, direct injection GC-ion mobility spectrometry, active sampling thermal desorption GC-differential mobility spectrometry and a prototype remote early detection system for survivor location were used to monitor the evolution of the metabolite plumes that were generated. Oxygen levels within the void simulator were allowed to fall no lower than 19.1% (v). Concurrent levels of carbon dioxide built up to an average level of 1.6% (v) in the breathing zone of the participants. Temperature, humidity, carbon dioxide levels and the physiological measurements were consistent with a reproducible methodology that enabled the metabolite plumes to be sampled and characterized from the different parts of the experiment. Welfare and safety data were satisfactory with pulse rates, blood pressures and oxygenation, all within levels consistent with healthy adults. Up to 12 in-test welfare assessments per participant and a six-week follow-up Stanford Acute Stress Response Questionnaire indicated that the researchers and participants did not experience any adverse effects from their involvement in the study. Preliminary observations confirmed that CO(2), NH(3) and acetone were effective markers for trapped humans, although interactions with water absorbed in building debris needed further study. An unexpected observation from the NH(3) channel was the suppression of NH(3) during those periods when the participants slept, and this will be the subject of further study, as will be the detailed analysis of the casualty detection data obtained from the seven instruments used.

Physiology and biochemistry of human subjects during entrapment.

A classification of various categories of entrapped people under the ruins of collapsed buildings after earthquakes, technical failures or explosions is proposed. Type and degree of injury at the moment of building collapse and duration of entrapment are the two basic parameters in this classification. The aim is to provide sources and types of volatile organic compounds (VOCs) that can be used for establishing a new method for locating entrapped victims based on human chemical signatures. Potential target compounds, among others, are ammonia, acetone, isoprene, dimethylsulfide, dimethyldisulfide and trimethylamine. In this context, the possible neuroendocrine, metabolic and physical responses of potential victims during the different types of entrapment are correlated with the sources of VOCs such as expired air, urine, blood and sweat. The proposed classification scheme was developed as part of an integrated research project which investigates the use of combined audio, video and chemical methods for the early location of entrapped people under the ruins of collapsed buildings.

Permeation profiles of potential urine-borne biomarkers of human presence over brick and concrete

Headspace solid phase micro-extraction gas chromatography-mass spectrometry (SPME-GC-MS) analysis was performed over an in-house made filling chamber loaded with brick or concrete, mimicking a potential entrapment scene of building collapse following natural or man-made disasters. Permeation profiles of 22 volatile species, released by human urine samples, were quantitatively monitored over the selected debris materials for a time period of 24 hours (LODs ranged from 0.05-0.8 ppb, R(2) varied from 0.991-0.999 and RSDs 3-9%). Ketones were the most abundant constituents of urine vapor with eleven representatives followed by five aldehydes, two furans, two sulphur-containing compounds, one nitrile and one heterocyclic compound. The majority of the detected compounds were found below 10 ppb, with the exception of some ketones including acetone, 2-butanone and 2-pentanone. The influence of debris materials on the permeation profiles of analytes under study depended on their fundamental physicochemical properties. Less volatile and more soluble compounds in urine (ketones and aldehydes) were found to be present for longer time periods in the surroundings of the urine samples than the more volatile and poorly soluble ones (furans, sulphur-containing compounds). More specifically, ketones exhibited longer residence times in the filling chamber and strongly interacted with the debris materials as their molecular masses were increased; their profiles were found to be significantly modified in the presence of concrete. In general, concrete demonstrated a stronger interaction with urine species than brick, affecting the observed concentrations and residence times of released volatiles in the chamber.

A compendium of volatile organic compounds (VOCs) released by human cell lines

Volatile organic compounds (VOCs) offer unique insights into ongoing biochemical processes in healthy and diseased humans. Yet, their diagnostic use is hampered by the limited understanding of their biochemical or cellular origin and their frequently unclear link to the underlying diseases. Major advancements are expected from the analyses of human primary cells, cell lines and cultures of microorganisms. In this review, a database of 125 reliably identified VOCs previously reported for human healthy and diseased cells was assembled and their potential origin is discussed. The majority of them have also been observed in studies with other human matrices (breath, urine, saliva, feces, blood, skin emanations). Moreover, continuing improvements of qualitative and quantitative analyses, based on the recommendations of the ISO-11843 guidelines, are suggested for the necessary standardization of analytical procedures and better comparability of results. The data provided contribute to arriving at a more complete human volatilome and suggest potential volatile biomarkers for future validation. Dedication: This review is dedicated to the memory of Prof. Dr. Anton Amann, who sadly passed away on January 6, 2015. He was motivator and motor for the field of breath research.

Preliminary Investigation of Permeation Profiles of Selected Head-Space Urine Volatiles (2-Heptanone, n-Octanal) Using IMS

The late location of entrapped victims in collapsed buildings is the main reason of high mortality during urban search and rescue (USaR) operations after natural or man-made disasters. Consequently, an effort is currently being made to develop proper rescue searching tools that could improve the early location of trapped casualties. In this context, the knowledge of human scent profile and its behavior in the disaster environment is crucial. The main goal of this study was to investigate the suitability of the ion mobility spectrometry (IMS) for the quantitative monitoring of specific urine-borne volatile members of human scent interacting with the materials of collapsed dwellings. For this purpose, an ion mobility spectrometer with β-radiation source (63Ni) and an in-house made filling chamber mimicking the entrapment scene were employed. In preliminary experiments, quartz sand was used as imitating debris material. The experimental setup was used to investigate the permeation properties of two very promising urine-borne species, 2-heptanone and n-octanal, under the influence of two crucial operational factors; the size of quartz grain and the quartz layer thickness. 2-heptanone was found to penetrate through quartz layer by approximately a factor 4 faster than n-octanal. The twofold and threefold increase of quartz sand thickness lengthened the permeation times on average three and seven times for n-octanal, and three and five times for 2-heptanone. The presented experimental setup can be considered as a useful tool suitable for investigating the interactions of urine markers with the debris materials in the entrapment scene. However, further investigations involving different debris materials (e.g. concrete, brick, cement, wood, plastic, glass) and other urine-borne species are necessary, prior selecting a set of volatile organic compounds (VOCs) that will support the early location method of entrapped victims.

Factors that affect rescue time in urban search and rescue (USAR) operations

Recent structural collapses were studied in order to identify gaps in technology and to propose priorities in enhancing urban search and rescue (USAR) tools. The timelines of the events were examined with the scope of extracting critical factors that affect rescue time and can be used to define priorities in tools and technologies development, so that efficient and fast location, recovery and treatment of victims can be achieved. In this context, seven factors were identified: (1) best practices and lessons learned, (2) rescue technology, (3) community involvement, (4) information systems, (5) technology integration, (6) crisis management and (7) available budget. Each of these factors is reviewed, analyzed and discussed with the scope of providing future developments in tools and technology for USAR operations.

Dynamic vapor generator that simulates transient odor emissions of victims entrapped in the voids of collapsed buildings.

The design, development, and validation of a dynamic vapor generator are presented. The generator simulates human scent (odor) emissions from trapped victims in the voids of collapsed buildings. The validation of the device was carried out using a reference detector: a quadrupole mass spectrometer equipped with a pulsed sampling (PS-MS) system. A series of experiments were conducted for evaluating the simulators performance, defining types and weights of different factors, and proposing further optimization of the device. The developed device enabled the production of stable and transient odor profiles in a controllable and reproducible way (relative standard deviation, RSD < 11%) at ppbv to low ppmv concentrations and allowed emission durations up to 30 min. Moreover, the factors affecting its optimum performance (i.e., evaporation chamber temperature, air flow rate through the mixing chamber, air flow rate through the evaporation chamber, and type of compound) were evaluated through an analysis of variance (ANOVA) tool revealing the next steps toward optimizing the generator. The developed simulator, potentially, can also serve the need for calibrating and evaluating the performance of analytical devices (e.g., gas chromatographers, ion mobility spectrometers, mass spectrometers, sensors, e-noses) in the field. Furthermore, it can contribute in better training of urban search and rescue (USaR) canines.