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Odour Testing Methods and Regulatory Norms
Published in G. Thilagavathi, R. Rathinamoorthy, Odour in Textiles, 2022
Anton P. van Harreveld, Rajal Shinkre, Carmen Villatoro, Charlotte Tournier, Saisha Naik
Improving the olfactive attributes of any consumer product always involves the questions, “What unwanted olfactive attribute should I suppress?” or “Which desirable olfactive attribute should I enhance or even add?” This challenge can apply to the product or material itself, or it can be applicable within the context of its intended usage, as is the case in “active textiles,” which aim to remove unwanted odours in the user context, e.g., garments that reduce body odours caused by perspiration or textiles used in upholstery or curtains that aim to remove unwanted odours from indoor air, such as cooking odours or tobacco smoke odour. To determine a course of action in improving the olfactive attributes of a textile product, it is helpful to understand the interaction of the odour as human perception and the odorants that are involved on a molecular level. Ultimately, all odour perceptions are caused by volatile odorants, which can reach the olfactive neurons at the top of our nasal cavity to trigger olfactory receptor neurons, causing these to interact with the odorant to fire a neurological signal that is interpreted in the brain as an odour perception.
Homo Sapiens (“Us”): Strengths and Weaknesses
Published in Michael Hehenberger, Zhi Xia, Huanming Yang, Our Animal Connection, 2020
Michael Hehenberger, Zhi Xia, Huanming Yang
Smell or olfaction is a “chemical” sense, just as “taste.” In 1991, Richard Axel and Linda Buck50 discovered that hundreds of genes in our DNA are coding for the odorant sensors located in the olfactory sensory neurons in our noses. When an odorant attaches itself to the receptor, it triggers a protein change and an associated electric signal to be sent to the brain. Smells are composed of a large number of different substances and we interpret the varying signals from our receptors as specific scents. Odor molecules possess a variety of features and, thus, excite specific receptors more or less strongly. This combination of excitatory signals from different receptors makes up what we perceive as the molecule’s “smell.” In the brain, olfaction is processed by the olfactory system. Olfactory receptor neurons in the nose differ from most other neurons in that they die and regenerate on a regular basis. Figure 4.12 shows the peripheral olfactory system, which consists mainly of the nostrils, ethmoid bone, nasal cavity, and the olfactory epithelium, characterized by layers of thin tissue (covered in mucus) that line the nasal cavity. The layers of epithelial tissue include the mucous membranes, olfactory glands, olfactory neurons, and nerve fibers of the olfactory nerves.
Homo Sapiens (“Us”): Strengths and Weaknesses
Published in Michael Hehenberger, Zhi Xia, Our Animal Connection, 2019
Smell or olfaction is a “chemical” sense, just as “taste.” In 1991, Richard Axel and Linda Buck50 discovered that hundreds of genes in our DNA are coding for the odorant sensors located in the olfactory sensory neurons in our noses. When an odorant attaches itself to the receptor, it triggers a protein change and an associated electric signal to be sent to the brain. Smells are composed of a large number of different substances and we interpret the varying signals from our receptors as specific scents. Odor molecules possess a variety of features and, thus, excite specific receptors more or less strongly. This combination of excitatory signals from different receptors makes up what we perceive as the molecule’s “smell.” In the brain, olfaction is processed by the olfactory system. Olfactory receptor neurons in the nose differ from most other neurons in that they die and regenerate on a regular basis. Figure 4.12 shows the peripheral olfactory system, which consists mainly of the nostrils, ethmoid bone, nasal cavity, and the olfactory epithelium, characterized by layers of thin tissue (covered in mucus) that line the nasal cavity. The layers of epithelial tissue include the mucous membranes, olfactory glands, olfactory neurons, and nerve fibers of the olfactory nerves.
Biological function simulation in neuromorphic devices: from synapse and neuron to behavior
Published in Science and Technology of Advanced Materials, 2023
Hui Chen, Huilin Li, Ting Ma, Shuangshuang Han, Qiuping Zhao
Nowadays, gas sensor is increasingly important in our life for gas monitoring, food quality and healthcare applications such as breath based early diagnosis of diseases [139–141]. With the development of artificial intelligence, more and more gas sensors are integrated with memristors/neuromorphic devices to simulate human olfactory system. Li et al. [142] used 2D covalent organic framework (COF) film to develop a gas artificial synapse that can identify the alcohol atmospheres. Inspired by camel noses, Huang et al. [143] developed a highly sensitive and ultradurable neuromorphic capacitive humidity sensor that exhibited a robust capability to discriminate moisture from other volatile compounds. In the biological olfactory sensing system (Figure 10(b-i)), when the gas is sucked up into the nose, the odorant stimulates the olfactory receptors so that the chemical reactions between them trigger electrical signals as an output. These electrical signals are then transmitted to the olfactory bulb through glomeruli. Mitral cells and interneurons in the olfactory bulb can preprocess and transmit the electrical signals into the brain olfactory cortex to identify the odor.
Design and implementation of an electronic nose system for real-time detection of marijuana
Published in Instrumentation Science & Technology, 2021
Lucas Sampaio Leite, Valeria Visani, Paulo César Florentino Marques, Maria Aparecida Barreto Lopes Seabra, Natália Cybelle Lima Oliveira, Priscila Gubert, Victor Wanderley Costa de Medeiros, Jones Oliveira de Albuquerque, José Luiz de Lima Filho
E-nose systems simulate the mammalian olfactory response, where odor specificity, stemming from a unique response pattern, is generated from several hundred olfactory receptors.[25] In an e-nose, volatile compounds are introduced through the sampling mechanism and transferred to a chamber containing a matrix of sensors.[26] Under the influence of an odor stimulus, the sensor array generates a characteristic fingerprint corresponding to the smell of each sample. The sum of these fingerprints provides a recognition pattern for qualitative analysis using appropriate multivariate analysis tools based on these standards.[2,27] The most used algorithms include principal component analysis (PCA), linear discriminant analysis (LDA), discriminant function analysis (DFA), soft independent modeling of class analogies (SIMCA), and artificial neural networks (NAA).[28] These chemometric tools have been successfully applied in the development of methodologies aimed at solving forensic science problems, including gunpowder residues,[29] semen in tissues,[30] and counterfeit documents by identifying the inks.[31]