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Bioresource Technology Oct 2023Wastewater contains chemical compounds that cause malodors, such as ammonium cation, dimethyl sulfide, and volatile organic compounds. Biochar-based reduction in the... (Review)
Review
Wastewater contains chemical compounds that cause malodors, such as ammonium cation, dimethyl sulfide, and volatile organic compounds. Biochar-based reduction in the odorants has been proposed as an effective approach along with maintaining environmental neutrality as biochar is a sustainable material made from biomass and biowaste. Biochar can have high specific surface area and microporous structure with proper activation, appropriate for sorption purposes. Recently, various research directions have been proposed to determine the removal efficiency of biochar for different odorants contained in wastewater. This article is aimed at providing the most updated review of biochar-based removal of odor-causing compounds in wastewater while highlighting the current advances. It was distinguished that the odorant removal performance of biochar is highly associated with the raw material and modification method of biochar, and the kind of odorants. Further research should be required for more practical use of biochar for the reduction of odorants in wastewater.
Topics: Wastewater; Odorants; Adsorption; Charcoal; Water Pollutants, Chemical
PubMed: 37422094
DOI: 10.1016/j.biortech.2023.129419 -
Neuron Jul 2023Although the hippocampus is crucial for social memory, how social sensory information is combined with contextual information to form episodic social memories remains...
Although the hippocampus is crucial for social memory, how social sensory information is combined with contextual information to form episodic social memories remains unknown. Here, we investigated the mechanisms for social sensory information processing using two-photon calcium imaging from hippocampal CA2 pyramidal neurons (PNs)-which are crucial for social memory-in awake head-fixed mice exposed to social and non-social odors. We found that CA2 PNs represent social odors of individual conspecifics and that these representations are refined during associative social odor-reward learning to enhance the discrimination of rewarded compared with unrewarded odors. Moreover, the structure of the CA2 PN population activity enables CA2 to generalize along categories of rewarded versus unrewarded and social versus non-social odor stimuli. Finally, we found that CA2 is important for learning social but not non-social odor-reward associations. These properties of CA2 odor representations provide a likely substrate for the encoding of episodic social memory.
Topics: Mice; Animals; Odorants; CA2 Region, Hippocampal; Smell; Hippocampus; Learning; Discrimination Learning
PubMed: 37192623
DOI: 10.1016/j.neuron.2023.04.026 -
Nature Metabolism Sep 2023It is well-known that food-cue reactivity (FCR) is positively associated with body mass index (BMI) and weight change, but the mechanisms underlying these relationships... (Observational Study)
Observational Study
It is well-known that food-cue reactivity (FCR) is positively associated with body mass index (BMI) and weight change, but the mechanisms underlying these relationships are incompletely understood. One prominent theory of craving posits that the elaboration of a desired substance through sensory imagery intensifies cravings, thereby promoting consumption. Olfaction is integral to food perception, yet the ability to imagine odours varies widely. Here we test in a basic observational study whether this large variation in olfactory imagery drives FCR strength to promote adiposity in 45 adults (23 male). We define odour-imagery ability as the extent to which imagining an odour interferes with the detection of a weak incongruent odour (the 'interference effect'). As predicted in our preregistration, the interference effect correlates with the neural decoding of imagined, but not real, odours. These perceptual and neural measures of odour imagery are in turn associated with FCR, defined by the rated craving intensity of liked foods and cue-potentiated intake. Finally, odour imagery exerts positive indirect effects on changes in BMI and body-fat percentage over one year via its influences on FCR. These findings establish odour imagery as a driver of FCR that in turn confers risk for weight gain.
Topics: Adult; Humans; Male; Adiposity; Odorants; Craving; Obesity; Weight Gain
PubMed: 37640944
DOI: 10.1038/s42255-023-00874-z -
Environmental Microbiology Sep 2023Geosmin may be the most familiar volatile compound, as it lends the earthy smell to soil. The compound is a member of the largest family of natural products, the... (Review)
Review
Geosmin may be the most familiar volatile compound, as it lends the earthy smell to soil. The compound is a member of the largest family of natural products, the terpenoids. The broad distribution of geosmin among bacteria in both terrestrial and aquatic environments suggests that this compound has an important ecological function, for example, as a signal (attractant or repellent) or as a protective specialized metabolite against biotic and abiotic stresses. While geosmin is part of our everyday life, scientists still do not understand the exact biological function of this omnipresent natural product. This minireview summarizes the current general observations regarding geosmin in prokaryotes and introduces new insights into its biosynthesis and regulation, as well as its biological roles in terrestrial and aquatic environments.
Topics: Odorants; Bacteria; Naphthols; Sensation
PubMed: 36999338
DOI: 10.1111/1462-2920.16381 -
Journal of Agricultural and Food... Dec 2023Because food flavor is perceived through a combination of odor and taste, an analytical method that covers both dimensions would be very beneficial for mapping the...
Because food flavor is perceived through a combination of odor and taste, an analytical method that covers both dimensions would be very beneficial for mapping the consistent product quality over the entirety of a manufacturing process. Such a method, so-called "unified flavor quantitation", has been successfully applied to several different food products in recent years. The simultaneous detection of aroma and taste compounds by means of ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) enables the analysis and quantification of an enormously large number of compounds in a single run. To evaluate the limits of this method, chocolate, a high-fat, complex matrix, was selected. In 38 distinct commercial chocolate samples, 20 flavor-active acids, aldehydes, and sugars were analyzed after a simple, rapid extraction step followed by derivatization with 3-nitrophenylhydrazine using a single UHPLC-MS/MS method. The results obtained highlight the great potential of the "unified flavor quantitation" approach and demonstrate the possibility of high-throughput quantitation of key aroma- and taste-active molecules in a single assay.
Topics: Chocolate; Tandem Mass Spectrometry; Cacao; Odorants; Chromatography, High Pressure Liquid; Taste
PubMed: 38084639
DOI: 10.1021/acs.jafc.3c06868 -
Nature Neuroscience Sep 2023Odor perception is inherently subjective. Previous work has shown that odorous molecules evoke distributed activity patterns in olfactory cortices, but how these...
Odor perception is inherently subjective. Previous work has shown that odorous molecules evoke distributed activity patterns in olfactory cortices, but how these patterns map on to subjective odor percepts remains unclear. In the present study, we collected neuroimaging responses to 160 odors from 3 individual subjects (18 h per subject) to probe the neural coding scheme underlying idiosyncratic odor perception. We found that activity in the orbitofrontal cortex (OFC) represents the fine-grained perceptual identity of odors over and above coarsely defined percepts, whereas this difference is less pronounced in the piriform cortex (PirC) and amygdala. Furthermore, the implementation of perceptual encoding models enabled us to predict olfactory functional magnetic resonance imaging responses to new odors, revealing that the dimensionality of the encoded perceptual spaces increases from the PirC to the OFC. Whereas encoding of lower-order dimensions generalizes across subjects, encoding of higher-order dimensions is idiosyncratic. These results provide new insights into cortical mechanisms of odor coding and suggest that subjective olfactory percepts reside in the OFC.
Topics: Humans; Odorants; Brain; Smell; Amygdala; Neuroimaging
PubMed: 37620443
DOI: 10.1038/s41593-023-01414-4 -
Environmental Pollution (Barking, Essex... May 2024This review would like to point out the state-of-art of the European legislation for the odour pollution determination and management. Odour is generated by a mixture of... (Review)
Review
This review would like to point out the state-of-art of the European legislation for the odour pollution determination and management. Odour is generated by a mixture of more or less volatile and persistent compounds that surround us in daily life. European directives impose the use of corresponding technical standards for the application of the limits imposed. The different approaches (chemicals and/or olfactometries) and integrated evaluation methods for measuring and characterizing odour, even if in a very different way in the European territories, will be reviewed and commented. Specifically, the authors will describe and comment the main procedures for odour concentration determination (e.g., multigas sensors, electronic sensors for odour monitoring). It is important to note that the definition of odour does not take into account if an odour is "good" or "bad", but only if it exists. The limit value must guarantee a total equivalent level of environmental protection and does not involve a greater polluting load in the environment. Further, a deep revision of the Italian situation in terms of legislation and studies, will complete the paper.
Topics: Odorants; Environmental Monitoring; Environmental Pollution; Italy
PubMed: 38336139
DOI: 10.1016/j.envpol.2024.123525 -
Neuropsychopharmacology : Official... Mar 2024Social interactions are rewarding and protective against substance use disorders, but it is unclear which specific aspect of the complex sensory social experience drives...
Social interactions are rewarding and protective against substance use disorders, but it is unclear which specific aspect of the complex sensory social experience drives these effects. Here, we investigated the role of olfactory sensory experience on social interaction, social preference over cocaine, and cocaine craving in rats. First, we conducted bulbectomy on both male and female rats to evaluate the necessity of olfactory system experience on the acquisition and maintenance of volitional social interaction. Next, we assessed the effect of bulbectomy on rats given a choice between social interaction and cocaine. Finally, we evaluated the influence of olfactory sensory experience by training rats on volitional partner-associated odors, assessing their preference for partner odors over cocaine to achieve voluntary abstinence and assessing its effect on the incubation of cocaine craving. Bulbectomy impaired operant social interaction without affecting food and cocaine self-administration. Rats with intact olfactory systems preferred social interaction over cocaine, while rats with impaired olfactory sense showed a preference for cocaine. Providing access to a partner odor in a choice procedure led to cocaine abstinence, preventing incubation of cocaine craving, in contrast to forced abstinence or non-contingent exposure to cocaine and partner odors. Our data suggests the olfactory sensory experience is necessary and sufficient for volitional social reward. Furthermore, the active preference for partner odors over cocaine buffers drug craving. Based on these findings, translational research should explore the use of social sensory-based treatments utilizing odor-focused foundations for individuals with substance use disorders.
Topics: Rats; Male; Female; Animals; Pharmaceutical Preparations; Odorants; Craving; Cocaine; Self Administration; Substance-Related Disorders
PubMed: 38129664
DOI: 10.1038/s41386-023-01778-y -
Journal of Hazardous Materials Aug 2023Volatile organic compounds (VOCs) are gaseous chemicals found in ambient air and exhaled breath. In particular, highly reactive aldehydes are frequently found in... (Review)
Review
Volatile organic compounds (VOCs) are gaseous chemicals found in ambient air and exhaled breath. In particular, highly reactive aldehydes are frequently found in polluted air and have been linked to various diseases. Thus, extensive studies have been carried out to elucidate disease-specific aldehydes released from the body to develop potential biomarkers for diagnostic purposes. Mammals possess innate sensory systems, such as receptors and ion channels, to detect these VOCs and maintain physiological homeostasis. Recently, electronic biosensors such as the electronic nose have been developed for disease diagnosis. This review aims to present an overview of natural sensory receptors that can detect reactive aldehydes, as well as electronic noses that have the potential to diagnose certain diseases. In this regard, this review focuses on eight aldehydes that are well-defined as biomarkers in human health and disease. It offers insights into the biological aspects and technological advances in detecting aldehyde-containing VOCs. Therefore, this review will aid in understanding the role of aldehyde-containing VOCs in human health and disease and the technological advances for improved diagnosis.
Topics: Animals; Humans; Volatile Organic Compounds; Odorants; Electronic Nose; Receptors, Odorant; Aldehydes; Breath Tests; Biomarkers; Mammals
PubMed: 37156042
DOI: 10.1016/j.jhazmat.2023.131555 -
Frontiers in Neural Circuits 2024In the mouse olfactory system, odor information is converted to a topographic map of activated glomeruli in the olfactory bulb (OB). Although the arrangement of... (Review)
Review
In the mouse olfactory system, odor information is converted to a topographic map of activated glomeruli in the olfactory bulb (OB). Although the arrangement of glomeruli is genetically determined, the glomerular structure is plastic and can be modified by environmental stimuli. If the pups are exposed to a particular odorant, responding glomeruli become larger recruiting the dendrites of connecting projection neurons and interneurons. This imprinting not only increases the sensitivity to the exposed odor, but also imposes the positive quality on imprinted memory. External odor information represented as an odor map in the OB is transmitted to the olfactory cortex (OC) and amygdala for decision making to elicit emotional and behavioral outputs using two distinct neural pathways, innate and learned. Innate olfactory circuits start to work right after birth, whereas learned circuits become functional later on. In this paper, the recent progress will be summarized in the study of olfactory circuit formation and odor perception in mice. We will also propose new hypotheses on the timing and gating of olfactory circuit activity in relation to the respiration cycle.
Topics: Animals; Mice; Sensation; Smell; Odorants; Amygdala; Perception
PubMed: 38434487
DOI: 10.3389/fncir.2024.1342576