scholarly journals From Gas Sensors to Biomimetic Artificial Noses

Chemosensors ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 32 ◽  
Author(s):  
Paolo Pelosi ◽  
Jiao Zhu ◽  
Wolfgang Knoll
Keyword(s):  
Gas Sensors ◽  
Olfactory System ◽  
Recent Literature ◽  
State Of The Art ◽  
Olfactory Receptors ◽  
Electronic Circuits ◽  
Gas Detectors ◽  
Extreme Sensitivity ◽  
Novel Approaches ◽  
Human Nose

Since the first attempts to mimic the human nose with artificial devices, a variety of sensors have been developed, ranging from simple inorganic and organic gas detectors to biosensing elements incorporating proteins of the biological olfactory system. In order to design a device able to mimic the human nose, two major issues still need to be addressed regarding the complexity of olfactory coding and the extreme sensitivity of the biological system. So far, only 50 of the approximately 300–400 functioning olfactory receptors have been de-orphanized, still a long way from breaking the human olfactory code. On the other hand, the exceptional sensitivity of the human nose is based on amplification mechanisms difficult to reproduce with electronic circuits, and perhaps novel approaches are required to address this issue. Here, we review the recent literature on chemical sensing both in biological systems and artificial devices, and try to establish the state-of-the-art towards the design of an electronic nose.

scholarly journals Perceptual consciousness and cognitive access: an introduction

2018 ◽  
Vol 373 (1755) ◽  
pp. 20170340 ◽  
Author(s):  
Peter Fazekas ◽  
Morten Overgaard
Keyword(s):  
Recent Literature ◽  
State Of The Art ◽  
Subjective Experiences ◽  
Neural Basis ◽  
Theme Issue ◽  
Perceptual Consciousness ◽  
Cognitive Access ◽  
Methodological Problems ◽  
Novel Approaches ◽  
Access Mechanisms

The problem of perceptual consciousness—the question of how our subjective experiences (colours as we see them; sounds as we hear them; tastes, etc., as we feel them) could be accounted for in terms of brain processes—is often regarded as the greatest unsolved mystery of our times. In recent literature, one of the most pressing questions in this regard is whether the neural basis of perceptual consciousness is independent of the neural basis of cognitive access mechanisms that make reporting and reflecting on conscious experiences possible. The Theme Issue focuses on this central problem of consciousness research and aims to contribute to the field by critically discussing state-of-the-art empirical findings, identifying methodological problems and proposing novel approaches. This article is part of the theme issue ‘Perceptual consciousness and cognitive access’.

scholarly journals Titanium Dioxide-Based64∘YXLiNbO3Surface Acoustic Wave Hydrogen Gas Sensors

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
A. Z. Sadek ◽  
D. Buso ◽  
A. Martucci ◽  
P. Mulvaney ◽  
W. Wlodarski ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Acoustic Wave ◽  
Gas Sensors ◽  
Sol Gel ◽  
Hydrogen Gas ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Helium Atmosphere ◽  
Gas Detectors ◽  
Hydrogen Gas Sensors

Amorphous titanium dioxide (TiO2) and gold (Au) dopedTiO2-based surface acoustic wave (SAW) sensors have been investigated as hydrogen gas detectors. The nanocrystal-dopedTiO2films were synthesized through a sol-gel route, mixing a Ti-butoxide-based solution with diluted colloidal gold nanoparticles. The films were deposited via spin coating onto64∘YXLiNbO3SAW transducers in a helium atmosphere. The SAW gas sensors were operated at various temperatures between 150 and310∘C. It was found that gold doping onTiO2increased the device sensitivity and reduced the optimum operating temperature.

scholarly journals Novel Approaches Towards Highly Selective Self-Powered Gas Sensors

2015 ◽  
Vol 120 ◽  
pp. 623-627 ◽  
Author(s):  
M.W.G. Hoffmann ◽  
O. Casals ◽  
A.E. Gad ◽  
L. Mayrhofer ◽  
C. Fàbrega ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Novel Approaches ◽  
Self Powered

Single Cell Spike Activity in the Olfactory Bulb

1956 ◽  
Vol 186 (2) ◽  
pp. 255-257 ◽  
Author(s):  
Raymond R. Walsh
Keyword(s):  
Olfactory Bulb ◽  
Single Cell ◽  
Spike Activity ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Class I ◽  
Olfactory Stimulation ◽  
Fundamental Characteristic ◽  
Class Iii ◽  
Discharge Patterns

Studies of single-cell spike discharges in the olfactory bulb of the rabbit indicate the presence of three classes of neurons as characterized by their discharge patterns. Cells of class I discharge continuously and spontaneously; class II cells discharge intermittently in bursts, in synchrony with the passage of air through the nose. Cells of classes I and II are unmodified during olfactory stimulation. It appears there are many cells in the olfactory bulb whose discharge patterns are unrelated to excitation of the olfactory receptors by odors. Cells of class III respond to appropriate odors; the response of such cells to some odors and not others indicates that odor specificity is a fundamental characteristic of the olfactory system.

scholarly journals Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling

2020 ◽  
Author(s):  
Giulia Ischia ◽  
Luca Fiori
Keyword(s):  
Organic Waste ◽  
Review Paper ◽  
Recent Literature ◽  
State Of The Art ◽  
Hydrothermal Carbonization ◽  
Residual Biomass ◽  
Current State ◽  
Potential Applications ◽  
Intrinsic Complexity ◽  
Context Models

Abstract Hydrothermal carbonization (HTC) is an emerging path to give a new life to organic waste and residual biomass. Fulfilling the principles of the circular economy, through HTC “unpleasant” organics can be transformed into useful materials and possibly energy carriers. The potential applications of HTC are tremendous and the recent literature is full of investigations. In this context, models capable to predict, simulate and optimize the HTC process, reactors, and plants are engineering tools that can significantly shift HTC research towards innovation by boosting the development of novel enterprises based on HTC technology. This review paper addresses such key-issue: where do we stand regarding the development of these tools? The literature presents many and simplified models to describe the reaction kinetics, some dealing with the process simulation, while few focused on the heart of an HTC system, the reactor. Statistical investigations and some life cycle assessment analyses also appear in the current state of the art. This work examines and analyzes these predicting tools, highlighting their potentialities and limits. Overall, the current models suffer from many aspects, from the lack of data to the intrinsic complexity of HTC reactions and HTC systems. Therefore, the emphasis is given to what is still necessary to make the HTC process duly simulated and therefore implementable on an industrial scale with sufficient predictive margins. Graphic Abstract

scholarly journals Olfactory Stimulation Effect of Aldehydes, Nonanal, and Decanal on the Human Electroencephalographic Activity, According to Nostril Variation

Biomedicines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 57 ◽  
Author(s):  
Minju Kim ◽  
Kandhasamy Sowndhararajan ◽  
Hae Jin Choi ◽  
Se Jin Park ◽  
Songmun Kim
Keyword(s):  
Olfactory System ◽  
Power Spectra ◽  
Brain Regions ◽  
Eeg Power Spectra ◽  
Beta Power ◽  
Eeg Changes ◽  
Electroencephalographic Activity ◽  
Healthy Participants ◽  
Human Nose ◽  
Better Than

Fragrances play a pivotal role in humans’ psychological and physiological functions through the olfactory system. Aldehydes are important organic compounds with a variety of fragrance notes. Particularly, nonanal (C9) and decanal (C10) aldehydes are important natural fragrant components used to enhance floral, as well as citrus notes in perfumery products. In general, each nostril of the human nose is tuned to smell certain odor molecules better than others due to slight turbinate swelling between the nostrils. Hence, the objective of the present investigation was aimed to evaluate the influence of binasal and uninasal inhalations of C9 and C10 aldehydes on human electroencephalographic (EEG) activity. Twenty healthy participants (10 males and 10 females) participated in this study. The EEG readings were recorded from 8 electrodes (QEEG-8 system) according to the International 10-20 System. The results revealed that C10 exposure exhibited significantly different EEG changes, during binasal and uninasal inhalations. In different brain regions, C10 odor markedly decreased the absolute alpha and absolute beta power spectra. In regards to C9 odor, significant changes of EEG power spectra were noticed only during binasal inhalation. In addition, C10 mainly produced changes at the left parietal site (P3) than other brain sites. In conclusion, the variations in EEG activities of C9 and C10 aldehydes might be owing to their characteristic fragrance quality, as well as the influence of nostril differences.

scholarly journals The role of SNMPs in insect olfaction

2020 ◽  
Author(s):  
Sina Cassau ◽  
Jürgen Krieger
Keyword(s):  
Membrane Proteins ◽  
Olfactory System ◽  
Critical Role ◽  
Olfactory Receptors ◽  
Wide Distribution ◽  
Insect Olfaction ◽  
Survival And Reproduction ◽  
Odorant Binding ◽  
Encoding Genes

AbstractThe sense of smell enables insects to recognize olfactory signals crucial for survival and reproduction. In insects, odorant detection highly depends on the interplay of distinct proteins expressed by specialized olfactory sensory neurons (OSNs) and associated support cells which are housed together in chemosensory units, named sensilla, mainly located on the antenna. Besides odorant-binding proteins (OBPs) and olfactory receptors, so-called sensory neuron membrane proteins (SNMPs) are indicated to play a critical role in the detection of certain odorants. SNMPs are insect-specific membrane proteins initially identified in pheromone-sensitive OSNs of Lepidoptera and are indispensable for a proper detection of pheromones. In the last decades, genome and transcriptome analyses have revealed a wide distribution of SNMP-encoding genes in holometabolous and hemimetabolous insects, with a given species expressing multiple subtypes in distinct cells of the olfactory system. Besides SNMPs having a neuronal expression in subpopulations of OSNs, certain SNMP types were found expressed in OSN-associated support cells suggesting different decisive roles of SNMPs in the peripheral olfactory system. In this review, we will report the state of knowledge of neuronal and non-neuronal members of the SNMP family and discuss their possible functions in insect olfaction.

scholarly journals Revisiting 3D chromatin architecture in cancer development and progression

2020 ◽  
Vol 48 (19) ◽  
pp. 10632-10647
Author(s):  
Yuliang Feng ◽  
Siim Pauklin
Keyword(s):  
Phase Separation ◽  
Cancer Progression ◽  
Genome Organization ◽  
State Of The Art ◽  
Human Cancer ◽  
Cancer Development ◽  
Transcriptional Dysregulation ◽  
Chromatin Architecture ◽  
Novel Approaches ◽  
Promoter Interaction

Abstract Cancer development and progression are demarcated by transcriptional dysregulation, which is largely attributed to aberrant chromatin architecture. Recent transformative technologies have enabled researchers to examine the genome organization at an unprecedented dimension and precision. In particular, increasing evidence supports the essential roles of 3D chromatin architecture in transcriptional homeostasis and proposes its alterations as prominent causes of human cancer. In this article, we will discuss the recent findings on enhancers, enhancer–promoter interaction, chromatin topology, phase separation and explore their potential mechanisms in shaping transcriptional dysregulation in cancer progression. In addition, we will propose our views on how to employ state-of-the-art technologies to decode the unanswered questions in this field. Overall, this article motivates the study of 3D chromatin architecture in cancer, which allows for a better understanding of its pathogenesis and develop novel approaches for diagnosis and treatment of cancer.

Phantom Smelling

2002 ◽  
Vol 94 (3) ◽  
pp. 841-850 ◽  
Author(s):  
George Grouios
Keyword(s):  
Neuronal Activity ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Brain Structures ◽  
Neural Representation ◽  
Olfactory Organ ◽  
Olfactory Perception ◽  
Serious Injury ◽  
Normal Input

A case of phantom smelling (phantosmia) is described in a 28-yr.-old man who developed permanent bilateral anosmia after a serious injury to olfaction-related brain structures at the age of 25 years. The findings indicate that, even years after loss of input from olfactory receptors, the neural representation of olfactory perception can still recreate olfactory sensations without any conscious recall of them. This indicates that the neural representation of olfactory sensations remains functional and implies that neuronal activity in the olfactory organ or in other brain structures gives rise to olfactory experiences perceived as originating from the perception of original odor substances. The report suggests the intriguing possibility that the olfactory perception is not a passive process that merely reflects its normal input from the olfactory system but is continuously generated by a neural representation in the olfactory organ or in other olfaction-related brain structures, based on both genetic and sensory determinants. To the author's knowledge this is the first reported case of its kind.

scholarly journals Efficient Self-Heating in Nanowire Sensors: Prospects for Very-Low Power

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 829
Author(s):  
Cristian Fàbrega ◽  
Olga Casals ◽  
Joan Daniel Prades
Keyword(s):  
Gas Sensors ◽  
State Of The Art ◽  
Electronic Devices ◽  
Power Demand ◽  
Heating Effect ◽  
Warm Up ◽  
Self Heating ◽  
Probing Signal ◽  
The Subject ◽  
And Control

Self-heating operation, or the use of the resistance-probing signal to warm up and control the temperature of nanowire devices, has been the subject of research for more than a decade. The state-of-the-art shows that this approach is serving to lower the power demand in temperature-activated devices, especially in conductometric gas sensors, but the simplicity of eliminating the heating element comes with the complexity of integrating 1-dimensional nanomaterials in electronic devices. The advantages of the efficient self-heating effect in nanowires have already been probed in a broad range of systems and materials. But when it comes to transfer this operating principle to new systems and materials natural doubts arise: how to do it?, how much savings in power will be achieved? We will address these questions in this review contribution.

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