Olfactory Odor Research Articles

Odor lateralization test is insensitive to small degrees of intranasal trigeminal activation.

Odors with prominent trigeminal compounds are more easily localized than purely olfactory ones. However, it is still unclear whether adding a small amount of a trigeminal compound to an olfactory odor significantly improves lateralization performance. We included 81 healthy adults aged 25.4 ± 4.8 years to complete odor lateralization tasks using 12 odors: two "olfactory", two "trigeminal" odors, and eight odor mixtures at two low concentrations of "trigeminal" odors (4%, 8%). This task utilized a "Squeezer" delivering odor or air to either nostril, and participants indicated which nostril received the odor. Evaluations also included olfactory function, odor intensity ratings, and individual olfactory importance. Degrees of trigeminal compounds significantly affected lateralization performance (F = 82.32, p < 0.001), with 100% irritants showing higher performance than 0%, 4%, and 8% irritants (p's < 0.001), while no significant differences were found between odors with 0%, 4%, and 8% irritants (p's > 0.05). Chi-square tests confirmed higher percentages of above-chance lateralization with 100% irritants than with 0%, 4%, and 8% irritants (χ2 = 30.89 to 47.33, p's < 0.001). Adding a small amount of a trigeminal compound to a selective olfactory odor does not significantly improve lateralization performance. Trigeminal lateralization likely follows an "accumulative" pattern rather than an "all or none" rule. With only 20 trials, the task may lack sensitivity to detect low levels of trigeminal irritation in selective olfactory odors, though it does not rule out trigeminal activation. The odor lateralization task can screen for odors with prominent trigeminal compounds by comparing group-level performance with that of purely olfactory odors. Future studies should use more ideal stimuli (e.g., PEA for olfactory, CO2 for trigeminal) to test the replicability of the results.

Image presentation and effective classification of odor intensity levels using multi-channel electronic nose technology combined with GASF and CNN

This paper proposes a novel data processing scheme for electronic noses that combines the gramian angular field (GAF) and convolutional neural network (CNN) to achieve high performance in classifying five levels of odor intensity. Specifically, a multi-channel e-nose was developed to detect various gases, including hydrogen sulfide, ammonia, sulfur dioxide, trimethylamine, and alkane gases, among others, in complex odor components. The sensor array was optimized through Spearman correlation analysis of the sensor signals and artificial olfactory odor intensity levels. Moreover, the one-dimensional temporal sensor data was converted into two-dimensional color images using the GAF (GASF/GADF) algorithm. This approach enables a more detailed presentation of deep features while retaining the time-domain dependence of the signals. To enhance the performance of classification, a multi-scale feature fusion network (MFFNet) was designed. Notably, GASF-converted images are more effective in characterizing sensor data for different odor intensity levels than GADF-converted images. Compared to classical CNN classification models such as AlexNet, GoogLeNet, and ResNet18, MFFNet achieved the highest accuracy and macro average F1-score on the test set, which were 93.75% and 93.34%, respectively. The results demonstrate the efficient classification of odor intensity levels by combining multi-channel e-nose technology, GASF, and CNN.

An Integrated Audio-Visual-Olfactory Virtual Reality False Feeding Device: Research, Development, and Design

To resolve the problem of the lack of sensory stimulation from the colors and aromas of food when patients are given enteral nutrition support by tube feeding or simple oral administration, an immersive virtual reality (VR) sham feeding device integrating audio, visual, and olfactory sense perceptions was developed independently and the usability of the device was tested. Relying on the multidisciplinary cooperation of nursing, mechanical engineering, and computer science and using as a reference the characteristics of gastric tube and oxygen tube placement in clinical patients, we carried out 3D modeling and printing of the exterior framework of the odor box. Unity 3d.5.x, a mainstream virtual engine tool, was used to create scenarios. The device could create visual stimulation through 3 VR dining scenarios, 23 kinds of food, and comfortable dining environment. The sound of chewing was played to simulate the dining process and provide auditory stimulation. Through the independently researched and developed olfactory odor box, corresponding food aromas were sprayed out for olfactory stimulation. After the equipment prototype was created, 10 patients were recruited to perform users' subjective evaluation of the usability of the equipment. A VR sham feeding device integrating audio-visual-olfactory stimulation was successfully developed. In the visual effect evaluation, all users commented that the vision was clear and unimpeded, and that the menu program could follow their rotation movement. Eight people considered the scenes to be rather realistic. In the auditory effect evaluation, all users stated that the volume of the sound was appropriate, and that they would hear a chewing sound being played when the food was approaching. In the olfactory effect evaluation, 9 people stated that they smelled the food aromas when the food was approaching, and that they thought the odor was real or partially real. On the whole, the equipment was convenient to use and all users thought that the equipment had clear presentation and could run stably and smoothly. No adverse reactions, such as dizziness, occurred in any users. Successfully presenting visual, auditory, and olfactory stimuli, the prototype device passed the subjective usability test. The prototype device effectively expands the application prospects of VR in the medical field. In the future, it will be applied to patient populations, including surgical patients, patients with eating disorders, obesity, and loss of appetite, and other patients who cannot take in food through their mouths. The prototype device provides new ideas for promoting enhanced recovery after surgery and improving patient experience.

The effect of olfactory odour stimulation on serum oxytocin levels and glucose metabolism: Data from the OLFAMET study

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Analyses on the influence of normal nasal morphological variations on odorant transport to the olfactory cleft

Objective Olfaction requires a combination of sensorineural components and conductive components, but conductive mechanisms have not typically received much attention. This study investigates the role of normal nasal vestibule morphological variations in ten healthy subjects on odorant flux in the olfactory cleft. Materials and methods Computed tomography images were used to create subject-specific nasal models. Each subject’s unilateral nasal cavity was classified according to its nasal vestibule shape as Standard or Notched. Inspiratory airflow simulations were performed at 15 L/min, simulating resting inspiration using computational fluid dynamics modeling. Odorant transport simulations for three odorants (limonene, 2,4-dinitrotoluene, and acetaldehyde) were then performed at concentrations of 200 ppm for limonene and acetaldehyde, and 0.2 ppm for dinitrotoluene. Olfactory cleft odorant flux was computed for each simulation. Results and discussion and conclusion Simulated results showed airflow in the olfactory cleft was greater in the Standard phenotype compared to the Notched phenotype. For Standard, median airflow was greatest in the anterior region (0.5006 L/min) and lowest in the posterior region (0.1009 L/min). Median airflow in Notched was greatest in the medial region (0.3267 L/min) and lowest in the posterior region (0.0756 L/min). Median olfactory odorant flux for acetaldehyde and limonene was greater in Standard (Acetaldehyde: Standard = 140.45 pg/cm2-s; Notched = 122.20 pg/cm2-s. Limonene: Standard = 0.67 pg/cm2-s; Notched = 0.65 pg/cm2-s). Median dinitrotoluene flux was greater in Notched (Standard = 2.86 × 10−4pg/cm2-s; Notched = 4.29 × 10−4 pg/cm2-s). The impact of nasal vestibule morphological variations on odorant flux at the olfactory cleft may have implications on individual differences in olfaction, which should be investigated further.

Exposure-response Relationship and Chemical Characteristics of Atmospheric Odor Pollution from a Cigarette Factory

Odor pollution is one of the most complained environmental problems in China. At present, the odor control is mainly aimed at municipal facilities. There is a lack of reports on the atmospheric odor pollution produced by some special industrial emissions. This paper studied the odor impact of a cigarette factory on surrounding residents in order to obtain the exposure-response relationship, which can provide a scientific basis for odor control of cigarette production. Exhaust emission measurement, sample collection and laboratory analysis, as well as community survey were carried out. The air dispersion model Aermod was used to simulate the olfactory odor concentrations in surrounding residential areas. Face-to-face questionnaire was used to collect the information of residential responses to the cigarette odor. The exposure-response relationship between the percentage of highly annoyed people (%) and the 98th percentile of odor concentrations was analyzed using the univariate binomial logistic model. In addition, the typical odor pollutants were found by odor activity value. The results showed that the proportion of highly annoyed people in the residential area was ranged from 5% to 64%, and the acceptable level of exposure odor concentration was 4 OU m–3 at the 98th percentile. The main odor substances of the cigarette factory were oxygenated organic substances including esters, fatty acids and ketones. Based on the chemical composition and the odor character of each substance, the odor wheel of cigarette factory was established for the first time.

Machine Learning Refutes Loss of Smell as a Risk Indicator of Diabetes Mellitus.

Because it is associated with central nervous changes, and olfactory dysfunction has been reported with increased prevalence among persons with diabetes, this study addressed the question of whether the risk of developing diabetes in the next 10 years is reflected in olfactory symptoms. In a cross-sectional study, in 164 individuals seeking medical consulting for possible diabetes, olfactory function was evaluated using a standardized clinical test assessing olfactory threshold, odor discrimination, and odor identification. Metabolomics parameters were assessed via blood concentrations. The individual diabetes risk was quantified according to the validated German version of the “FINDRISK” diabetes risk score. Machine learning algorithms trained with metabolomics patterns predicted low or high diabetes risk with a balanced accuracy of 63–75%. Similarly, olfactory subtest results predicted the olfactory dysfunction category with a balanced accuracy of 85–94%, occasionally reaching 100%. However, olfactory subtest results failed to improve the prediction of diabetes risk based on metabolomics data, and metabolomics data did not improve the prediction of the olfactory dysfunction category based on olfactory subtest results. Results of the present study suggest that olfactory function is not a useful predictor of diabetes.

Habitual Exposure to Trigeminal Stimuli and Its Effects on the Processing of Chemosensory Stimuli

Our objective was to compare brain responses to trigeminal and olfactory stimuli in frequent and non-frequent gum chewers in order to explore whether habitual exposure to trigeminal stimuli affects their central-nervous processing. In healthy subjects, fMRI brain scans were obtained for 20 frequent gum chewers (GC) and 20 non-frequent gum chewers (N′GC), in response to four odorous stimuli; 2 ‘trigeminal’ (peppermint and spearmint) and 2 non-trigeminal or ‘olfactory’ (cherry and strawberry). During measurements, subjects reported intensity and pleasantness ratings for all stimuli. In addition, a test for general trigeminal sensitivity test (lateralization test) and an odor threshold test was performed. Brain activations in response to individual odors were investigated for the total study population followed by group wise (GC and N′GC) analysis separately for responses to trigeminal (peppermint + spearmint) and olfactory (cherry + strawberry) odors.(1) The GC group exhibited higher trigeminal sensitivity compared to the N′GC group. (2) Olfactory odors activated bilateral insular cortex and amygdala. Apart from olfactory areas (amygdala, insular cortex), trigeminal odors also produced activations in right thalamus and right substantia nigra. (3) In the GC group, olfactory odors produced higher bilateral insular cortex activation than in N′GC group, but no such differences were observed for trigeminal odors. GC subjects appeared to be more responsive to trigeminal chemosensory stimuli. However, this did not directly translate into differences in central-nervous activations to trigeminal stimuli; instead, the use of chewing gum was associated with stronger brain activation towards olfactory stimuli.

Molecular and functional characterization of buffalo nasal epithelial odorant binding proteins and their structural insights by in silico and biochemical approaches

The olfactory system is capable of detecting and distinguishing thousands of environmental odorants that play a key role in reproduction, social behaviours including pheromones influenced classical events. Membrane secretary odorant binding proteins (OBPs) are soluble lipocalins, localized in the nasal membrane of mammals. They bind and carry odorants within the nasal epithelium to putative olfactory transmembrane receptors (ORs). OBP has not yet been exploited to develop a suitable technique to detect oestrus which is being reported as a difficult task in buffalo. In the present study, using molecular biology and protein engineering approaches, we have cloned six novel OBP isoforms from buffalo nasal epithelium odorant-binding proteins (bnOBPs). Furthermore, 3 D models were developed and molecular-docking, dynamics experiments were performed by in silico approaches. In particular, we found four residues (Phe104, Phe134, Phe69 and Asn118) in OBP1a, which contributed to favourable interactions towards two sex pheromones, specifically oleic acid and p-cresol. We expressed this protein in Escherichia coli from female buffalo urine and validated through fluorescence quenching studies to show similar strong binding affinities of OBP1a to oleic acid and p-cresol. By using structural data, the binding specificity was also verified by site-directed mutagenesis of the four residues followed by in vitro binding assays. Our results enable us to better understand the functions of different nasal epithelium OBP isoforms in buffaloes. They also lead to improved understanding of the interaction between olfactory proteins and odorants to develop highly selective biosensing devices for non-invasive detection of oestrus in buffaloes. Communicated by Ramaswamy H. Sarma

Study on the characterization of domestic odor facilities by using the olfactory field odor method in a domestic industrial complex area

Study on the characterization of domestic odor facilities by using the olfactory field odor method in a domestic industrial complex area

Odor pollution due to industrial emission of volatile organic compounds: A case study in Hefei, China

Abstract Odor pollution as an environmental nuisance has attracted a lot of public attention. A great number of volatile organic compounds are capable of causing odor problems, most of which are accompanied by adverse health effects. Volatile organic compound samples were collected from different sites in the high-tech industry development zone in Hefei, including various kinds of factories and residential areas. The samples were analyzed by gas chromatography and mass spectrometry detection, and the analysis results showed that the concentrations of total volatile organic compounds ranged from 285.30 to 1802.30 ppbv. Among the 80 specific volatile organic compounds studied, 46 compounds detected could lead to odor pollution according to the odor threshold. To provide comprehensive characterization of odor pollution, instrumental analysis combined with olfactory measurement were conducted in this study. Odor volatile organic compounds were characterized by using olfactory odor concentration, odor index and coefficient of divergence analysis methods. According to the results, the automobile components manufacturing plants and electric products plants exhibited the highest concentrations of odor volatile organic compounds among all the major emission sites, especially during the injection molding and spraying. Specifically, 1,4-diethylbenzene was the most abundant odorous contributor in this study. Furthermore, the profiles of each volatile organic compounds at the industrial sites were quite different from those at the residential sites, which can be deduced that the surrounding residential zones were not strongly affected by the volatile organic compounds emission from the industrial zones.

LncRNA profile of Apis mellifera and its possible role in behavioural transition from nurses to foragers

BackgroundThe behavioural transition from nurses to foragers in honey bees is known to be affected by intrinsic and extrinsic factors, including colony demography, hormone levels, brain chemistry and structure, and gene expression in the brain. However, the molecular mechanism underlying this behavioural transition of honey bees is still obscure.ResultsThrough RNA sequencing, we performed a comprehensive analysis of lncRNAs and mRNAs in honey bee nurses and foragers. Nurses and foragers from both typical colonies and single-cohort colonies were used to prepare six libraries to generate 49 to 100 million clear reads per sample. We obtained 6863 novel lncRNAs, 1480 differentially expressed lncRNAs between nurses and foragers, and 9308 mRNAs. Consistent with previous studies, lncRNAs showed features distinct from mRNAs, such as shorter lengths, lower exon numbers, and lower expression levels compared to mRNAs. Bioinformatic analysis showed that differentially expressed genes were mostly involved in the regulation of sensory-related events, such as olfactory receptor activity and odorant binding, and enriched Wnt and FoxO signaling pathways. Moreover, we found that lncRNAs TCONS_00356023, TCONS_00357367, TCONS_00159909 and mRNAs dop1, Kr-h1 and HR38 may play important roles in behavioural transition in honey bees.ConclusionThis study characterized the expression profile of lncRNAs in nurses and foragers and provided a framework for further study of the role of lncRNAs in honey bee behavioural transition.

Olfactory Identification, Odor Hedonics, and Atypical Behaviors

Olfactory Identification, Odor Hedonics, and Atypical Behaviors

Odor Problems in Toilets with Reduced Ventilation Frequencies

Japan’s toilets are generally ventilated 15 times per hour. Despite the development in toilets, the ventilation frequency in toilets has not been changed in recent times. Therefore, there is a possibility that toilets are being excessively ventilated. Reducing the ventilation frequency increases the return air to the heat exchanger and improves the efficiency of the heat exchanger. For an optimal ventilation frequency, we introduce a system that could control the exhaust air using sensors. The primary issue is the odor caused by reducing the ventilation frequency. In this study, we aim to eliminate the odor as quickly as possible by providing an exhaust port at the bottom of the wall (hereinafter referred as “baseboard deodorization”). First, we examined the relationship among the odor sensor, human’s olfactory odor identification and ventilation volumes with the toilet in operation to verify the usefulness of the sensors. Next, the air environment was analyzed using computational fluid dynamics (CFD). The results of the measurements and questionnaire survey indicate a correlation between the degree of contamination in the air and the odor intensity. The CFD analyses demonstrated, even after the frequency of ventilation reduced to 5 times per hour, that the ammonia concentration obtained was equivalent to 15 times per hour. To solve the odor problem due to the ventilation reduction, it is important to evacuate air immediately after the odor is generated. Among others, it was observed that a baseboard deodorization system contributes significantly to the reduction in ammonia concentration.

Remote monitoring and real-time abatement of odor emitted from sewer using odor sensors, wireless communication technique and microbial deodorant

&lt;p&gt;In this study, a new technology was introduced to monitor the odor occurrence situation at the remote site in real time and the technology to reduce sewage odor by using microbial deodorant. Long-term monitoring and full-scale test was carried out to investigate the odor concentration in the combined sewer using the real - time odor monitoring device which consist of 3 odor sensors with the wireless communication technique, and to investigate the effect of the microbial deodorant on the reduction of sewer odor. The odor monitoring device, which was fabricated using metal oxide semiconductor sensors and code division multi access communication technique, was installed at three sites of the gravity-flow type combined sewer (depth 3m and width 5m) in Gangnam, Seoul. Odor monitoring in field was carried out at the interval of 10 minutes for 304 days over the autumn, winter and summer. The measured results were transmitted to Woosong odor research center about 100km away from the site. The measured sensor value was converted to olfactory odor concentration by the co-relation equation of the sensor value and the olfactory odor concentration. As the monitoring results, more than 40,000 sewage odor data were obtained. The average odor concentration of raw sewage in combined sewer was 464 OUk, which was 321 OUk in winter and 412 OUk in autumn and 659 OUk in summer. The commercial microbial deodorant used in this study was the mixture culture of 48 microbial strains, and the microbial deodorant of 1 m3 d-1 to 2 m3 d-1 was mixed with raw sewage at the 1.5 km upstream of the site where odor complaints occurred. As the experimental results, the average odor concentration of sewage mixed with microbial deodorant was 113 OUk, which was 102 OUk in winter and 298 OUk in autumn and 153 OUk in summer. It was estimated that the odor reduction effect of sewer odor by microbial deodorant is about 74%.&lt;/p&gt;

Study on the characterization of domestic odor facilities by using the olfactory field odor measurement method

Study on the characterization of domestic odor facilities by using the olfactory field odor measurement method

RFamidergic neurons in the olfactory centers of the terrestrial slug Limax

BackgroundThe terrestrial slug Limax has long been used as a model for the study of olfactory information processing and odor learning. Olfactory inputs from the olfactory epithelium are processed in the tentacular ganglion and then in the procerebrum. Glutamate and acetylcholine are the major neurotransmitters used in the procerebrum. Phe-Met-Arg-Phe-NH2 (FMRFamide) has been shown to be involved in the regulation of the network activity of the procerebrum. Although there are thought to be various RFamide family peptides other than FMRFamide that are potentially recognized by anti-FMRFamide antibody in the central nervous system of mollusks, identifying the entire repertoire of RFamide peptides in Limax has yet to be achieved.MethodsIn the present study, we made a comprehensive search for RFamide peptide-encoding genes from the transcriptome data of Limax, and identified 12 genes. The expression maps of these RFamide genes were constructed by in situ hybridization in the cerebral ganglia including the procerebrum, and in the superior/inferior tentacles.ResultsTen of 12 genes were expressed in the procerebrum, and nine of 12 genes were expressed in the tentacular ganglia. Gly-Ser-Leu-Phe-Arg-Phe-NH2 (GSLFRFamide), which is encoded by two different genes, LFRFamide1 (Leu-Phe-Arg-Phe-NH2–1) and LFRFamide2 (Leu-Phe-Arg-Phe-NH2–2), decreased the oscillatory frequency of the local field potential oscillation in the procerebrum when exogenously applied in vitro. We also found by immunohistochemistry that the neurons expressing pedal peptide send efferent projections from the procerebrum back to the tentacular ganglion.ConclusionOur findings suggest the involvement of a far wider variety of RFamide family peptides in the olfactory information processing in Limax than previously thought.

Development of Children’s Olfactory Abilities and Odor Awareness Is Not Predicted by Temperament: a Longitudinal Study

Temperament affects olfaction in cross-sectional studies. However, it is not clear whether it is linked to olfactory development. Here we examined the links between temperament and olfaction over a nearly 2-year period, expecting that children showing higher levels of negative affectivity would exhibit greater odor awareness across repeated testing. As a subsidiary aim, we investigated whether olfactory scores differ as a function of olfactory performance at a younger age. The participants were 73 Czech children (mean age = 5.8 years). Their olfactory abilities were assessed using the Sniffin’ Sticks, and odor awareness was evaluated with the Children’s Olfactory Behaviors in Everyday Life Questionnaire. These were reassessed 21 months later. Mothers provided information on the children’s temperament by completing the Short Form of the Children’s Behavior Questionnaire at the same interval. Children’s temperament was not found to relate to olfactory development over a 21-month period. Odor identification and awareness, but not odor discrimination and threshold, differed as a function of scores achieved at an earlier age. Odor identification and awareness predict themselves over a 21-month period. Links between temperament and olfaction may be only beginning to form at preschool age. While this study suggests that temperament does not play a role in olfactory development, longitudinal studies over a broader timespan are needed to determine the robustness of this finding.

Identification and comparison of candidate odorant receptor genes in the olfactory and non-olfactory organs of Holotrichia oblita Faldermann by transcriptome analysis

A sophisticated olfactory system is part of the explanation for the prominence of insects among animals because of the essential roles of the olfactory system in foraging, host seeking, mating, ovipositing and avoiding toxic substances. In this study, we sequenced and analysed the transcriptomes of olfactory tissue (antennae) and non-olfactory tissue (legs) of the scarab beetle, Holotrichia oblita Faldermann, which is a serious underground pest in China. We obtained approximately 80.2 million 150bp reads that were assembled into 61,038 unigenes with an average length of 890bp. Among the transcripts, 70% of the unigenes were annotated. A total of 44 odorant receptors (ORs) and 9 ionotropic receptors (IRs) were identified based on homology searches. Then, quantitative real-time PCR experiments were performed to investigate the expression patterns of 32 putative chemosensory genes. The results showed that these genes were highly expressed in olfactory organs (antennae) and might play a key role in the olfaction-related behaviours in H. oblita. Based on the results of our phylogenetic analysis and the detailed tissue and sex-biased expression characteristics, the different roles of the receptor proteins in the olfactory system were also indicated. The results of this study will provide the foundation for further understanding of the olfactory odorant receptors of H. oblita at the molecular level and ultimately help to develop novel targets for manipulating this pest.

Characteristics of volatile compound emission and odor pollution from municipal solid waste treating/disposal facilities of a city in Eastern China.

Transfer station, incineration plant, and landfill site made up the major parts of municipal solid waste disposal system of S city in Eastern China. Characteristics of volatile compounds (VCs) and odor pollution of each facility were investigated from a systematic perspective. Also major index related to odor pollution, i.e., species and concentration of VCs, olfactory odor concentration, and theoretic odor concentration, was quantified. Oxygenated compounds and hydrocarbons were the most abundant VCs in the three facilities. Different chemical species were quantified, and the following average concentrations were obtained: transfer station, 54 VCs, 2472.47μg/m3; incineration plant, 75 VCs, 33,129.25μg/m3; and landfill site, 71 VCs, 1694.33μg/m3. Furthermore, the average olfactory odor concentrations were 20,388.80; 50,677.50; and 4951.17, respectively. The highest odor nuisance was detected in the waste tipping port of the incineration plant. A positive correlation between the olfactory and chemical odor concentrations was found with R 2=0.918 (n=15, P<0.01). The result shows odor pollution risk transfer from landfill to incineration plant when adopting thermal technology to deal with the non-source-separated waste. Strong attention thus needs to be paid on the enclosed systems in incineration plant to avoid any accidental odor emission.