Chemical Profiling of Trace Odours for Forensic Identification: A Review

@#Trace odour is one of the trace material evidence that has significant value in forensic analysis. The recovery of relevant trace odour components from clothing has the potential to be a form of trace evidence that can be used to assess the likelihood of a contact between individuals in sexual and violent cases. They have the same potential as other trace evidence and can narrow down the suspect in the investigation. Studies conducted previously related to trace odour have succeeded in proving that this trace odour is unique, has its signature profile and can distinguish it from other sources such as fingerprints and DNA. This review highlights these trace odours and their persistence after being transferred, which contribute to a complete picture of the dynamics and potential application in the forensic reconstruction process. The literature was sourced from electronic databases such as Scopus, PubMed, Springer Link, Wiley On¬line Library and Science Direct. Keywords such “odour”, “trace odour”, “scent”, “volatile organic compound”, “forensic identification” were utilised. Further studies on various forms of trace odour are needed to strengthen their evidential values and be admissible to the court.

Characterization of odour-active volatiles and sensory analyses of roasted oak (Quercus humboldtii Bonpl) acorns, a coffee substitute / Caracterización de los compuestos activos olfativamente y análisis sensorial de los frutos tostados del roble (Quercus humboldtii Bonpl), como una bebida sustituta de café

Background: Oak acorns are roasted and grounded to produce a powder that is used to prepare a coffee substitute beverage. Objective: To identify the odour-active volatiles of the powder derived from roasted acorns of Quercus humboldtii and to perform a quantitative descriptive analysis (QDA) of its appearance, odour, and taste. Methods: The odour-active volatiles of roasted oak acorn powder were extracted by SDE and analyzed by GC/MS and olfactory analyses (GC/O). Sensorial analyses of this beverage were done by QDA (Quantitative Descriptive Analysis). Results: Nineteen compounds were identified, showing acid, buttery/caramel, smoke/roasted, and fruity odour notes, which are common to those of roasted coffee. Ketones, aldehydes, aliphatic acids, furanic alcohols and pyrazines were identified as relevant for this coffee substitute beverage. The major volatile compounds were furfural, 5-methyl furfural, furfuryl alcohol, and 3-hydroxy-2-butanone, some of them related to the sugar breakdown by heating. Odour attributes characterized by QDA, were in agreement with those detected by GC-O (Gas Chromatography coupled to Olfactometry), but some off-taste notes were detected. Conclusions: The results of molecular sensory approach confirmed that this product resembles coffee; however, QDA analyses showed the presence of undesirable taste. More studies are needed in order to improve the taste quality of this coffee substitute.

Antecedentes: los frutos del roble se tuestan y muelen para producir un polvo que es empleado en la preparación de una bebida sustituta del café. Objetivos: identificar los compuestos volátiles activos olfativamente presentes en el polvo proveniente de los frutos tostados de Quercus humboldtii; así como llevar a cabo un análisis cuantitativo descriptivo (QDA) de la apariencia, olor y sabor de este polvo. Métodos: os compuestos volátiles activos olfativamente del polvo de los frutos tostados del roble se extrajeron por DES y se analizaron por CG-EM y análisis olfativo (CG-O). La caracterización sensorial de esta bebida sustituta de café fue realizada mediante el empleo de QDA. Resultados: se identificaron diecinueve compuestos y se evidenció la presencia de notas de olor como manteca/caramelo, ahumado/tostado y frutal, similares a las encontradas en el café tostado. Los componentes mayoritarios identificados para este sustituto de café fueron cetonas, aldehídos, ácidos alifáticos, alcoholes furánicos y pirazinas. Los compuestos mayoritarios detectados fueron furfural, 5-metil furfural, alcohol furfurílico y 3-hidroxi-2-butanona, algunos de ellos relacionados con la descomposición térmica de azúcares. Los atributos de olor caracterizados por QDA fueron similares a los detectados por CG-O, aunque se detectaron algunas notas de sabor desagradable. Conclusiones: los resultados del molecular sensory approach confirmaron que este producto se parece al café; sin embargo el QDA mostró la presencia de un sabor desagradable. Estudios adicionales son necesarios para mejorar la calidad del sabor de este sustituto de café.

Identification of Sulfur Fumigated Chrysanthemi Flos with Electronic Nose Technology / 世界科学技术-中医药现代化

This study was aimed to identify Chrysanthemi Flosbefore and after sulfur fumigation based on its different odour by the electronic nose technology.It was expected to explore a new method for the Chrysanthemi Flos identification according to the odour.The electronic nose technology was used in the detection of peak response values of Chrysanthemi Flos on sensor array.The principal component analysis (PCA) and 10 machine learning (ML) ways were used in the analysis of response values and establishment of optimized identification models.The results showed that there was a significant difference in the odour between sulfur fumigated Chrysanthemi Flos and non-sulfur fumigated ones.The identification models were successful with high correct judge rate by PCA and 6 ML ways including BF Tree,J48 and Random Tree.It was concluded that the electronic nose technology can be used for the accurate identification of sulfur fumigated Chrysanthemi Flos and non-sulfur fumigated ones.The electronic nose technology combined with multiple ML methods can be introduced in the quality evaluation of Chrysanthemi Flos.It provided more ideas for the application of electronic nose in data mining for traditional Chinese medicine (TCM) studies.

Odour correlation study during preparation process of Gastrodiae Rhizoma Formula Granule / 中草药

Objective: To study the change and correlation of odour during the preparation process of Gastrodiae Rhizoma-pieces- extract-formula granules. A new overall evaluation index of preparation process was introduced to investigate the preparation process of Chinese medicinal granules, which was in line with the overall concept of traditional Chinese medicine (TCM). Methods: The odour data of all samples were collected using an electronic nose technology. Then the characteristic data were analyzed through statistical methods, such as principal component analysis (PCA), discriminant factor analysis (DFA), and statistical quality control analysis (SQCA). Results: The odour loss was very small during the preparation process of herb-pieces-extract; while the odour loss during extract-formula granules process was bigger. This prompted that it was feasible to evaluate the technology of TCM formula particles according to the existing mode of chemical drugs, but it was different from the evaluation results using the overall concept of TCM as evaluation index. Conclusion: The electronic nose technology could be used for collecting odour data of Gastrodiae Rhizoma samples in different forms. Through data analysis with various models, the difference and correlation among different odour of Gastrodiae Rhizoma samples could be identified. The odour could be used as the overall evaluation index during the preparation process of Gastrodiae Rhizoma Formula Granule.

Antipredator and alarm reaction responses of silver catfish (Rhamdia quelen) juveniles exposed to waterborne ammonia

Ammonia has relatively toxic effects on fish and other aquatic organisms. This study examined whether juvenile silver catfish exposed to alarm substances released by conspecifics and predators in water with different ammonia levels modify their behaviour in response to the perceived risk of predation. We used juvenile catfish that were naive to predators. The fish were raised from the larval stage in the laboratory and kept in 40-L aquaria at waterborne NH3 concentrations of 0, 0.05, 0.1, or 0.2 mg L-1 for 10 days. The alarm substances used were predator odour and skin extract from conspecifics. The juveniles were transferred to 2-L aquaria for the antipredator and alarm reaction behavioural tests, which were performed on days 1, 5 and 10 after initial exposure to ammonia. The test aquaria contained a shelter at one end of the tank. The trials consisted of a 10-min prestimulus and a 10-min poststimulus observation period. The results of the study suggest that naive juvenile catfish are able to identify predators and skin extract from conspecifics by odour. In addition, waterborne NH3 levels modify the antipredator response of this species.

Amônia possui efeito relativamente tóxico em peixes e outros organismos aquáticos. Este estudo examinou se juvenis de jundiás modificam seu comportamento em resposta a percepção do risco de predação quando expostos a substâncias de alarme liberadas por conspecíficos e predadores em água com diferentes concentrações de amônia. Foram utilizados juvenis de jundiá nunca expostos a predadores. Os peixes foram criados em laboratório desde a fase larval e mantidos em aquários de 40-L contendo diferentes concentrações de NH3: 0; 0,05; 0,1 e 0,2 mg L-1 por 10 dias. As substâncias de alarme utilizadas foram odor de predador e extrato de pele de conspecíficos. Os juvenis foram transferidos para aquários de 2-L para realização dos testes para comportamento antipredador e resposta à substância de alarme, os quais foram realizados nos dias 1, 5 e 10 a partir do início da exposição à amônia. O aquário teste continha um esconderijo em uma de suas extremidades. Foram feitas observações comportamentais 10-min pré-estímulo e 10-min pós-estímulo. Os resultados do estudo sugerem que juvenis de jundiá nunca expostos a predadores são capazes de identificar predadores e extrato de pele de conspecíficos pelo odor. Além disso, os níveis de NH3 na água alteram a resposta anti-predatória desta espécie.

Oxidation of volatile reduced sulphur compounds in biotrickling filter inoculated with Thiobacillus thioparus

Reduced volatile sulphur compounds generate an impact on the environment, because of the bad smell and its low odour threshold. Compared with the existing physicochemical technologies for their elimination, biotrickling filters are an economically and environmentally sustainable alternative. Usually mixed cultures of microorganisms are used for inoculating biotrickling filters, in this case a pure culture of Thiobacillus thioparus is used for generating a biofilm, allowing to measure its capacity for the oxidation of four volatile reduced sulphur compounds: hydrogen sulphide, dimethyl sulphide, methyl mercaptan and dimethyl disulphide, using a residence time of 0.033 hrs. The viable cells of the biofilm were quantified by epifluorescence microscopy, staining the cells with ethidium bromide and acridine orange, polymerase chain reaction analysis in real time was used for testing the predominance of T. thiopharus in the biofilm. The microorganism was able to adhere and grow on the surface of rings made of polyethylene, with a viable population of 7•10(7) cell•ring-1, a 74 percent of total cells. The real time PCR showed a persistence of the population of T. thioparus for more than 300 days of operation, without being displaced by other microbial species. The maximum elimination capacities for each compound were 34.4; 21.8; 30.8 and 25.6 gS•m-3•h-1 for H2S, dimethylsulphide, dimethyldisulphide and methyl mercaptan, respectively. We conclude that it is possible to implement a biotrickling filter with the bacteria T. thioparus, which can oxidize volatile reduced sulphur compounds efficiently.

Alternativas para o controle de emissões odorantes em reatores anaeróbios tratando esgoto doméstico / Alternatives for the control of odorous emissions in anaerobic reactors treating domestic wastewater

Esta nota técnica busca consolidar as principais características, vantagens e desvantagens dos métodos usualmente empregados para o controle de emissões odorantes, discorrendo criticamente acerca da aplicabilidade de cada um dos métodos para o tratamento de odores em estações de tratamento de esgoto doméstico. Verificou-se que vários métodos são sofisticados, de elevado custo e, muitas vezes, não aplicáveis ao tratamento de odores emitidos em reatores anaeróbios tratando esgoto doméstico. Uma análise qualitativa dos vários métodos indica que a combustão direta e os processos bioquímicos são os que reúnem o maior conjunto de vantagens para o tratamento de gases residuais emitidos em reatores anaeróbios.

This technical note aims at consolidating the main characteristics, advantages and disadvantages of the methods usually applied to the control of odorous emissions, with a critical analysis upon the applicability of each method to the treatment of odours in treatment plants of domestic wastewater. It was verified that several methods are sophisticated, present high cost, and are often non-applicable to the treatment of odour emissions from anaerobic reactors treating domestic wastewater. The qualitative analysis of the various methods points out that direct combustion and biochemical processes gather more advantages for the treatment of waste gases produced in anaerobic reactors.

Effect of single bacterial starter culture on odour reduction during controlled fermentation of cassava tubers for foofoo production

Effects of single bacterial starter culture on odour reduction during controlled fermentation of cassava tubers for foofoo production were investigated. Pure cultures were used to ferment cassava tubers in water for 96 h. The cultures used include Bacillus subtilis, Klebsiela sp., Lactobacillus plantarum and Leuconostoc mesenteroides. L. plantarum exhibited the highest acid producing ability, decreasing the pH of the Cassava tubers from 6.2 to 3.68 with a corresponding increase in total titratable acidity (TTA) from 0.082% to 0.290% during the 96 h fermentation period. The effected changes in pH and TTA by other organisms ranged respectively from 4.88 and 0.135% for Klebsiella sp., 4.68 and 0.136% for L. mesenteroides to 4.90 and 0.139% for B. subtilis with in the period. All the cultures were found to contribute in varying degree to odour reduction in fermented cassava; B. subtilis effected the highest odour reduction followed by L. plantarum.

Drinking water: problems related to water supply in Bahía Blanca, Argentina / Agua potable: problemas en el abastecimiento de la ciudad de Bahía Blanca, Argentina

In April 2000, alterations in drinking water quality, such as turbidity and odors similar to those of organochloride pesticides, were detected at Bahía Blanca (Argentina). This fact was associated to reports of dermic reactions and respiratory problems in the population. Samples drawn from Paso de las Piedras reservoir, two water treatment plants of at inlet and outlet points and at several particular houses were analyzed. Total phytoplankton in the reservoir varied between 49440 and 84832 cells.ml-1, while dominant species was, Anabaena circinalis. Efficiency to remove microorganisms (ER) by the treatment plants considering cell number of total phytoplankton was analyzed. Bacteriological analysis, qualitative and quantitative studies of phytoplankton, pesticides, THM (trihalomethanes) and BTEX (benzene, toluene, ethylbenzene and xylene) analysis were carried out in samples of domestic supply and in the treatment plants. Even though samples were bacteriological potable, Anabaena circinalis and Microcystis aeruginosa algae were found at high concentrations in some cases. No pesticides were detected. THM and BTEX were below guideline values into recommendations for drinking water. Geosmin was responsible for detected odors. Besides, Copaene, another volatile metabolite, which on account in its structure could be considered a Geosmin precursor, was also detected. In Argentina, this was the first report of Cyanobacteria presence in drinking water.

En abril de 2000, en Bahía Blanca (Argentina), se detectaron alteraciones en el agua de bebida, turbidez y olor semejante a "Gamexane". Esto coincidió con la aparición de problemas dérmicos y respiratorios en la población. Para determinar el origen del problema, se analizaron muestras, tomadas en el embalse Paso de las Piedras, en las plantas potabilizadoras y en varios domicilios particulares. En el embalse, la densidad celular del fitoplancton, fluctuó entre 49440 y 84832 cél/ml-1, muy por encima de los valores de referencia. Anabaena circinalis en altas concentraciones fue la especie dominante (48320 - 84032 células por mililitro). Se cuantificó la eficiencia de las plantas de tratamiento (algas-entrada/algas-salida). Anabaena circinalis y Microcystis aeruginosa fueron encontradas a la entrada y a la salida de las plantas, indicando una baja eficiencia de las plantas de tratamiento. Para el agua domiciliaria, se realizaron estudios fitoplanctonicos; análisis bacteriológicos; presencia de plaguicidas, trihalometanos y BTEX. Si bien, bacteriológicamente el agua era potable, se encontraron Cyanobacteria en algunos casos en concentraciones muy altas. La presencia de pesticidas resultó negativa. La media de los THM y de los valores de BTEX resultaron menores a valores guías para agua potable. Se detectó la presencia de Geosmina, resultando el responsable del fuerte olor. Asimismo, se halló otro metabolito volátil, Copaene, que por su estructura pudiera llegar a considerarse precursor de la Geosmina. Este es el primer reporte de la presencia de cianobacterias en aguas de consumo humano en Argentina.

Interactions mediated by predators in arthropod food webs / Interações mediadas por predadores em teias alimentares de artrópodes

Studies on interactions among plants, herbivores and natural enemies are important for understanding population dynamics of species in food webs, but they are also important for the practice of pest control with natural enemies. Biological control programs heavily rely on the occurrence of trophic cascades, where the addition of one natural enemy causes a decrease of pest densities and an increase of plant biomass. However, when more that one natural enemy is used to control various pests in the same system, artificial food webs are created and simple tritrophic interactions change to more complicated ones. The occurrence of complex interactions and omnivory in these food webs may modify the sign and the strength of direct effects of natural enemies on pests. In this paper, we show and discuss the experimental results on interactions mediated by predators in an artificial food web that occurs on cucumber plants in greenhouses where biological control is applied. The two pests in this food web are the two-spotted spider mite Tetranychus urticae Koch, and the western flower thrips Frankliniella occidentalis (Pergande). The predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor) are used to control spider mites, and the generalist predatory bug Orius laevigatus (Fieber) and a specialist predatory mite Neoseiulus cucumeris (Oudemans) are predators of thrips. Results from behavioural studies showed that some of these species are attracted to the same patch and do not avoid each other's presence. We show some complex interactions arising from the meeting of these species: (a) the intraguild predation by O. laevigatus on P. persimilis, (b) the use of spider-mite web as a refuge by thrips larvae against their predators. The consequences of such interactions for population dynamics of predators and prey and their implications for success of biological control are discussed.

Estudos sobre interações entre plantas, herbívoros e inimigos naturais são importantes para o entendimento da dinâmica populacional das espécies em teias alimentares, bem como para o sucesso do controle de pragas por inimigos naturais. Os programas de controle biológico fundamentam-se na ocorrência de sucessões tróficas, onde a adição de um inimigo natural causa o decréscimo na densidade da presa/hospedeiro e o aumento da biomassa da planta. Entretanto, quando mais de uma espécie de inimigo natural é usada para controlar várias pragas no mesmo sistema, teias alimentares artificiais são criadas e as interações tritróficas simples transformam-se em outras mais complicadas. A ocorrência de interações complexas e de onivoria nestas teias alimentares pode modificar a direção e a intensidade dos efeitos diretos dos inimigos naturais sobre as pragas. Neste artigo, são apresentados e discutidos os resultados experimentais sobre interações mediadas por predadores em uma teia alimentar artificial. Esta teia é formada em plantas de pepino em casa de vegetação onde o controle biológico é aplicado. A teia constitui-se de duas pragas, o ácaro rajado Tetranychus urticae Koch e o tripes Frankliniella occidentalis (Pergande). Para o controle dos ácaros rajados são liberados os ácaros predadores Phytoseiulus persimilis Athias-Henriot e Neoseiulus californicus (McGregor). O controle dos tripes é feito através de liberações do percevejo generalista Orius laevigatus (Fieber) e do ácaro predador especialista Neoseiulus cucumeris (Oudemans). Resultados de estudos comportamentais mostraram que algumas destas espécies são atraídas para o mesma planta e não evitam plantas ocupados por outras espécies. Quando estas espécies são encontradas na mesma planta, interações complexas ocorrem: (a) predação intraguilda de O. laevigatus sobre P. persimilis, (b) uso da teia produzida pelo ácaro rajado pelas larvas de tripes como refúgio contra seus predadores. As conseqüências ...

The Study of Treatment of Odor Gas Emitted from the Wastewater Plant by the Biofilter / 微生物学通报

A pilot-scale research on purification of odorous gas emitted from wastewater treatment plant using a biofilter was conducted. The aim of this study is to check on the performance of biofilter running in various conditions and the effect of pH fluctuations on the performance of biofilter. The relation between distribution of microorganism and removal of odorous gases were also discussed here. The experimental results show that the predominant odor-causing gas can be efficiently eliminated by a biofilter inoculated with deodoring microorganism which were isolated previously. Moreover the biofilter had been proved having good tolerance to shocking loads of pollutant and can operate well in the condition of low pH.