A Study to Verify the Practicality of Introducing an Arson Dog (K-9) Unit in Field Investigations

Combustion improvers are often found in acts of arson. Until recently, in fire investigations in Korea, these substances have been identified only by the olfactory sense of the fire inspectors or conventional gas detectors. These methods are neither efficient nor feasible in damaged buildings or large areas. Research on the canine sense of smell has shown that a dog can distinguish the remains of combusted hydrocarbon compounds, even in a large, open area. Field tests confirmed that arson dogs can find combustion improvers at fire sites in about five to 77 s. Therefore, this study verified the practicality of introducing arson dog units in field investigations of fire sites to identify combustion improvers sprayed for committing arson.

Canine olfactory detection and its relevance to medical detection

The extraordinary olfactory sense of canines combined with the possibility to learn by operant conditioning enables dogs for their use in medical detection in a wide range of applications. Research on the ability of medical detection dogs for the identification of individuals with infectious or non-infectious diseases has been promising, but compared to the well-established and–accepted use of sniffer dogs by the police, army and customs for substances such as money, explosives or drugs, the deployment of medical detection dogs is still in its infancy. There are several factors to be considered for standardisation prior to deployment of canine scent detection dogs. Individual odours in disease consist of different volatile organic molecules that differ in magnitude, volatility and concentration. Olfaction can be influenced by various parameters like genetics, environmental conditions, age, hydration, nutrition, microbiome, conditioning, training, management factors, diseases and pharmaceuticals. This review discusses current knowledge on the function and importance of canines’ olfaction and evaluates its limitations and the potential role of the dog as a biomedical detector for infectious and non-infectious diseases.

Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

The year 2020 became the year of the outbreak of coronavirus, SARS-CoV-2, which escalated into a worldwide pandemic and continued into 2021. One of the unique symptoms of the SARS-CoV-2 disease, COVID-19, is the loss of chemical senses, i.e., smell and taste. Smell training is one of the methods used in facilitating recovery of the olfactory sense, and it uses essential oils of lemon, rose, clove, and eucalyptus. These essential oils were not selected based on their chemical constituents. Although scientific studies have shown that they improve recovery, there may be better combinations for facilitating recovery. Many phytochemicals have bioactive properties with anti-inflammatory and anti-viral effects. In this review, we describe the chemical compounds with anti- inflammatory and anti-viral effects, and we list the plants that contain these chemical compounds. We expand the review from terpenes to the less volatile flavonoids in order to propose a combination of essential oils and diets that can be used to develop a new taste training method, as there has been no taste training so far. Finally, we discuss the possible use of these in clinical settings.

What is the “Status questionis” of the e-nose. The future of artificial nose

An artificial nose (e-nose) is a multipotential electronic device, based on various sensors with the ability to recognize different odours, in the same way that the human olfactory sense does. An updated e-nose system will allow us to detect different oncological and/or degenerative diseases of the human being that today are diagnosed late. Other options would include providing specific information on the quality and condition of food, analysing and detecting the degree of environmental pollution, analysing perfumes and their essences, determining the composition and characteristics of certain beverages such as wine, tea, oil, cocoa and other products. The application of new technologies, such as artificial intelligence and nanotechnology, make it easier to distinguish many different odours in less time. In this paper, we have made a current investigation of the different types of e-nose existing today. Aim of the study Currently nanotechnology, artificial intelligence and computer science are tools that have revolutionary possibilities for the construction of a new e-nose device and progress over the current scopes. If we manage to unite the advantages provided by each of these new technologies that we have mentioned, we will be able to build a very useful device applicable in various fields such as health, food and beverage industry, perfumes and environment. Therefore, the objectives we have in this study are the following: To learn where artificial nose technology stands and what has been developed so far. Based on these findings, ask ourselves the following question: Is it possible to achieve an effective functioning or is it an unreachable project? To compile the majority of scientific articles published mainly in the last 10 years with examples of the use that has been made of artificial noses in the measurement of volatile compounds in the different fields mentioned. In the same way to gather the information published in the last years in relation to the usefulness, existence in the market and purposes of equipment that can measure the olfaction in the human being, what we will call the Smell-o-meter or olfactometer for human use. Material and Methods In the first part of this research we will gather most of the information existing so far in the international bibliography, as well as the achievements and utilities obtained to date. Following we will analyse all the new concepts related to e-nose devices that exist on sensors, gas chromatography, nanotechnology application, electronic engineering, materials and techniques as preliminary ideas for the development of the devices.

Assessment of the difference in detection of pleasant and unpleasant odors in different grades of hyposmia

Background Olfaction is a complex process involving different neurological mechanisms with a correlation between the chemical structure and quality of odors regarding pleasantness. This study aimed to compare the detection of pleasant and unpleasant odors in different grades of hyposmia. A descriptive cross-sectional study was conducted preceded by a preliminary pilot study, including 20 normal subjects without a history of hyposmia. The pilot study was carried out using the University of Pennsylvania Smell Identification Test (UPSIT) with the assessment of pleasantness of odors using a visual analog scale (VAS). Fifty patients diagnosed with organic hyposmia/anosmia were included in the main study and assessed for the degree of hyposmia/anosmia using UPSIT. The number of detected odors out of the five odors with highest VAS for pleasantness and five odors with lowest VAS for pleasantness, as detected by the pilot study, for every patient was assessed and compared. Results There was a significant difference between the detection of pleasant and unpleasant odors in mild, moderate, and severe hyposmia (p value = 0.02, 0.005, and 0.03 respectively) with a highly significant difference in the whole study group ( p < 0.00001) with more loss of ability to detect unpleasant odors compared with pleasant odors. Conclusion The current study showed significantly less ability to detect unpleasant odors compared with pleasant odors in different grades of hyposmia. This finding suggests that the pattern of degeneration of the olfactory sense organ is not uniform with the topographic nature of the olfactory membrane.

Dogs display owner-specific expectations based on olfaction

Most current knowledge about dogs’ understanding of, and reacting to, their environment is limited to the visual or auditory modality, but it remains unclear how olfaction and cognition are linked together. Here we investigate how domestic dogs search for their owners using their excellent olfactory sense. We raise the question whether dogs have a representation of someone when they smell their track. The question is what they expect when they follow a trail or whether they perceive an odour as a relevant or non-relevant stimulus. We adopted a classical violation-of-expectation paradigm—and as targets we used two persons that were both important to the dog, usually the owners. In the critical condition subjects could track the odour trail of one target, but at the end of the trail they find another target. Dogs showed an increased activity when the person did not correspond with the trail compared to a control condition. Moreover, we found huge individual differences in searching behaviour supporting the assumption that dogs are only able to smell when they really sniff, and that the temperature has an influence on dogs performance. Results are discussed in the light of how cognitive abilities, motivation and odour perception influence each other.

Utilization of a Gas-Sensing System to Discriminate Smell and to Monitor Fermentation during the Manufacture of Oolong Tea Leaves

The operational duration of shaking tea leaves is a critical factor in the manufacture of oolong tea; this duration influences the formation of its flavor and fragrance. The current method to control the duration of fermentation relies on the olfactory sense of tea masters; they monitor the entire process through their olfactory sense, and their experience decides the duration of shaking and setting. Because of this human factor and olfactory fatigue, it is difficult to define an optimum duration of shaking and setting; an inappropriate duration of shaking and setting deteriorates the quality of the tea. In this study, we used metal-oxide-semiconductor gas sensors to establish an electronic nose (E-nose) system and tested its feasibility. This research was divided into two experiments: distinguishing samples at various stages and an on-line experiment. The samples of tea leaves at various stages exhibited large differences in the level of grassy smell. From the experience of practitioners and from previous research, the samples could be categorized into three groups: before the first shaking (BS1), before the shaking group, and after the shaking group. We input the experimental results into a linear discriminant analysis to decrease the dimensions and to classify the samples into various groups. The results show that the smell can also be categorized into three groups. After distinguishing the samples with large differences, we conducted an on-line experiment in a tea factory and tried to monitor the smell variation during the manufacturing process. The results from the E-nose were similar to those of the sense of practitioners, which means that an E-nose has the possibility to replace the sensory function of practitioners in the future.

The morphohistology and fine anatomy of the olfactory organ in pabda catfish, Ompok bimaculatus (Bloch, 1794)

The organization of the olfactory system in Ompok bimaculatus (Siluriformes: Siluridae) were investigated by histological and ultrastructural analysis. The nasal chamber was totally engrossed by a boat shaped elongated olfactory rosette with numerous lamella. Histomicroscopically, each lamella was comprised of central core bounded on both sides by the cellular elements of olfactory epithelium. The central core was composed of thick connective tissue, nerve fibres and blood capillaries. The cellular components of the olfactory epithelium were identified based on their staining vigour, architecture, structural characteristics and surface features. The sensory epithelium contained morphologically recognizable ciliated, microvillous and rod receptor neurons. Labyrinth cells, scattered lymphatic cells, secretory mucous cells, stratified epithelial cells bearing microfolds and condensed ciliated supporting cells were observed in the indifferent epithelia. The basal cells were submerged in the deeper zone of mucosa above the basal lamina. Different sensory and nonsensory cells of the olfactory lining were associated with chemical stimulation of the fish studied. This species acquires a well developed olfactory sense for exploring the aquatic environment and able to determine the chemical changes in the surroundings.