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The Consumer Perception of Odour
Published in G. Thilagavathi, R. Rathinamoorthy, Odour in Textiles, 2022
Ingun Grimstad Klepp, Kirsi Laitala, R. Rathinamoorthy
The sense of smell or olfaction, the ability to perceive odours, is one of the most complex human senses as it depends on unique interactions between the olfactory system and diverse chemical substances. The olfactory system works as a defense mechanism for the human body against malodours and irritants. Much of its function and functionality is still unexplored (Reinarz 2014). The sense of smell is affected by chemical compounds in gaseous form. The olfactory epithelium, located at the top of the nasal cavity on both sides of the nasal septum, is a mucous membrane with olfactory cells, a type of nerve cell that is associated with the olfactory region of the brain. Similar to taste, the sense of smell is a chemical sense. The olfactory cells are stimulated only by volatile substances, i.e., by substances that evaporate and release molecules into the air. The odorants bind to odour receptors on the olfactory cells. This will trigger a biochemical reaction chain that leads to a nerve impulse, which in turn is sent to the brain (Winther 2018).
Acoustic Sensors
Published in J. David, N. Cheeke, Fundamentals and Applications of Ultrasonic Waves, 2017
Despite the interest in the use of arrays and the gas chromatograph described above, these devices are still a far cry from the mammalian nose in reality. The human olfactory system contains about a 100 million olfactory receptors with approximately 350 different types of receptor-binding proteins, distributed along part of the olfactory mucosa in the nose. A very first approximation to this would be to use blocks of sensors distributed along the coated column of a gas chromatograph type channel. This approach has been adopted by the Warwick group by Covington et al. [59] with a theoretical analysis by Sanchez-Montanes et al. [60]. This combines the spatial effect of the array with the temporal effect of the gas column to give an overall spatiotemporal response, which can be treated by the usual principal component analysis (PCA) [1]. The concept was realized by a silicon-based microsensor array coupled with a microfluidic package; while the sensors used in this study were resistive, the results should be valid for almost any sensor type. Each Si die was about 1 cm square and contained 80 microsensors. Five different polymer coatings were used to provide the basis for a number of five sensor arrays. The microfluidic package was fabricated by a microstereolithography machine, with overall channel dimensions 2.4 m × 0.5 mm × 0.5 mm. In the actual device, the channels were stacked so that the overall package was 36 mm × 27 mm × 7 mm in dimension. The channels were coated with parylene C, which has retention characteristics for the gases being studied. The system was initially tested with samples of ethanol and toluene vapor in air. Further tests were made with more complex odors (milk, cream, milk–cream mixture, vanilla, peppermint, and vanilla–peppermint mixture). The PCA analysis on the results was divided into three groups: spatiotemporal, spatial data only, and temporal data only. It was found that the spatiotemporal data gave the best clustering in the PCA plots, whereas the spatial data outperformed the temporal data. The total temporal delay in this study was 106 s, but this and other parameters will surely be improved with further research.
Recent advances in neuromorphic transistors for artificial perception applications
Published in Science and Technology of Advanced Materials, 2023
When interacting with the real, dynamic world, our activities are extremely complex. Each perception system always provides rich surrounding information to our brain to make decision. Thanks to the innovation of various functional materials and device structures, there are rapid progresses in neuromorphic devices to shape and imitate human perception systems. As mentioned previously in this review, artificial visual system, artificial tactile system, artificial auditory system, artificial olfactory system and artificial taste system have been constructed based on three-terminal neuromorphic transistors. Several functions of corresponding sensory systems have been imitated [47,129]. It is worth noting that human perception system is a complex system with multi-cue analysis, good integrity and synergy. However, there are few reports on artificial neuromorphic systems with multi-perception fusion. Therefore, the developments of neuromorphic platforms with multi-perceptual fusions will provide great significances to artificial intelligence and biomedicine.
A new perspective of aroma face mask on COVID-19 pandemic
Published in Journal of Medical Engineering & Technology, 2022
Fahimeh Irandoust, Salome Dini
The use of extracts and essential oils from aromatic plants dates back to ancient civilisations and even small societies and primitive tribes to strengthen and maintain health as well as boost physical and mental abilities. The Chinese people may have been one of the first cultures to use aromatic plants for well-being with 1000 years of history. Today, aromatherapy is one of the natural treatments used in holistic medicine in China [13]. It has even been accepted by the United States' State Board of Nursing as part of holistic nursing [14]. In Iranian Traditional Medicine, medicinal plants such as Carum carvi L. [15], Mentha piperita [16], Zataria multiflora Boiss. [17], Heracleum persicum Desf. ex Fisch [18], Berberis integrrima Bunge. [19], Satureja rechingeri [20] Ferula spp. [21,22], and Cuminum cyminum L. [23] are predominant agents to treatment of physical and mental disorders which have been scientifically proven [24–27]. The impact of aromas on human beings are divided into physiological and psychological effects. Its physiological effect acts directly on the organ and the psychological effect acts via the sense of smell or olfactory system, which in turn may cause physiological effects [24]. Clinical experience in aromatherapy suggests that beneficial effects of aromas or fragrances are not only exerted by inhalation of the vapour but also by absorption of fragrance molecules through the skin [25]. Inhaling the essential oil through the nasal mucosa and lung leads to systemic absorption of the aroma, which appears in the bloodstream only a few minutes after inhalation. Since these substances are lipophilic, they are absorbed by the brain and the nervous system [26]. A large number of studies show that the inhalation of fragrances highly influence on the brain function since the aromatics compositions are capable of crossing the blood-brain barrier and interact with receptors in the central nervous system [27,28]. Additionally, previous researches have suggested that the olfactory stimulation of aromas produces immediate changes in physiological parameters including pupil dilation, muscle tension, skin temperature, pulse rate blood pressure as well as brain activity [29–31]. There are several studies regarding the potential benefits of aromatherapy in anxiety, pain, vital signs, sleep quality, nausea, and stress [32–37]. A number of essential oils are currently in use as aromatherapy agents mainly R. damascena Mill. and E. globules.