scholarly journals Electronic Nose: Recent Developments in Gas Sensing and Molecular Mechanisms of Graphene Detection and Other Materials

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 80 ◽  
Author(s):  
Sylwia Orzechowska ◽  
Andrzej Mazurek ◽  
Renata Świsłocka ◽  
Włodzimierz Lewandowski
Keyword(s):  
Electronic Nose ◽  
Molecular Mechanisms ◽  
Electronic System ◽  
Radical Change ◽  
Electronic Charge ◽  
Detection Mechanism ◽  
Electronic Density ◽  
Area Of Interest ◽  
Sensitivity Improvement ◽  
Detection Mechanisms

The aim of the study was to present the possibility of the sensitivity improvement of the electronic nose (e-nose) and to summarize the detection mechanisms of trace gas concentrations. Our main area of interest is graphene, however, for the better understanding of the sensing mechanisms, it is crucial to review other sensors of similar functions. On the basis of our previous research, we explained the detection mechanism which may stay behind the graphene sensor’s sensitivity improvement. We proposed a qualitative interpretation of detection mechanisms in graphene based on the theory regarding the influence of metals and substituents on the electronic systems of carbon rings and heterocyclic aromatic ligands. The analysis of detection mechanisms suggests that an increase of the electronic density in graphene by attaching a substituent and stabilization of electronic charge distribution leads to the increase of graphene sensor conductivity. The complexation of porphyrins with selected metals stabilizes the electronic system and increases the sensitivity and selectivity of porphyrin-based sensors. Our research summary and proposed conclusions allow us to better understand the mechanisms of a radical change of graphene conductivity in the presence of trace amounts of various gases.

scholarly journals SybilEye: Observer-Assisted Privacy-Preserving Sybil Attack Detection on Mobile Crowdsensing

Information ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 198
Author(s):  
Junhyeok Yun ◽  
Mihui Kim
Keyword(s):  
Mobile Devices ◽  
Privacy Preserving ◽  
Attack Detection ◽  
Sybil Attack ◽  
Detection Mechanism ◽  
Mobile Crowdsensing ◽  
Detection Model ◽  
System A ◽  
Data Processor ◽  
Detection Mechanisms

Mobile crowdsensing is a data collection system using widespread mobile devices with various sensors. The data processor cannot manage all mobile devices participating in mobile crowdsensing. A malicious user can conduct a Sybil attack (e.g., achieve a significant influence through extortion or the generation of fake IDs) to receive an incentive or destroy a system. A mobile crowdsensing system should, thus, be able to detect and block a Sybil attack. Existing Sybil attack detection mechanisms for wireless sensor networks cannot apply directly to mobile crowdsensing owing to the privacy issues of the participants and detection overhead. In this paper, we propose an effective privacy-preserving Sybil attack detection mechanism that distributes observer role to the users. To demonstrate the performance of our mechanism, we implement a Wi-Fi-connection-based Sybil attack detection model and show its feasibility by evaluating the detection performance.

Enhanced processing of threatening stimuli: The case of face recognition

1995 ◽  
Vol 18 (2) ◽  
pp. 304-305
Author(s):  
Linda Mealey
Keyword(s):  
Face Recognition ◽  
Threat Detection ◽  
Detection Mechanism ◽  
Environmental Features ◽  
Context Dependent ◽  
Detection Mechanisms ◽  
Threatening Stimuli

AbstractBecause of their evolutionary importance, threat-detection mechanisms are likely to exist at a variety of levels. A recent study of face recognition suggests that novel stimuli receive enhanced processing when presented as fear-related. This suggests the existence of a complex, context-dependent threat-detection mechanism that can adaptively respond to spatiotemporally varying and unique environmental features.

scholarly journals A proteomics database for CNS proteins of the great pond snail Lymnaea stagnalis

2021 ◽  
Author(s):  
Sarah Wooller ◽  
Aikaterini Anagnostopoulou ◽  
Benno Kuropka ◽  
Michael Crossley ◽  
Paul R. Benjamin ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Lymnaea Stagnalis ◽  
Model Organism ◽  
Research Area ◽  
Biological Data ◽  
Model Organisms ◽  
Pond Snail ◽  
Data Sets ◽  
Area Of Interest ◽  
Age Related

Applications of key technologies in bioscientific and biomedical research, such as qRT-PCR or LC-MS based proteomics, are generating large biological data sets (omics data) which are useful for the identification and quantification of biomarkers involved in molecular mechanisms of any research area of interest. Genome, transcriptome and proteome databases are already available for a number of model organisms including vertebrates and invertebrates. However, there is insufficient information available for protein sequences of certain invertebrates, such as the great pond snail Lymnaea stagnalis, a model organism that has been used highly successfully in elucidating evolutionarily conserved mechanisms of learning and memory, ageing and age-related as well as amyloid beta induced memory decline. Here, we present the design and benchmarking of a new proteomics database (LymSt-PDB) for the identification of proteins from the Central Nervous System (CNS) of Lymnaea stagnalis by LC-MS based proteomics.

Electron Charge and Current Densities, the Geometrie Phase and Cellular Automata

1993 ◽  
Vol 48 (1-2) ◽  
pp. 134-136
Author(s):  
N. Sukumar ◽  
B. M. Deb ◽  
Harjinder Singh
Keyword(s):  
Current Density ◽  
Electron System ◽  
Time Dependent ◽  
Gauge Potential ◽  
Electronic Charge ◽  
Electronic Density ◽  
Electronic Current ◽  
Finite Set ◽  
The Many ◽  
Electronic Density Distribution

Some consequences of the quantum fluid dynamics formulation are discussed for excited states of atoms and molecules and for time-dependent processes. It is shown that the conservation of electronic current density j(r) allows us to manufacture a gauge potential for each excited state of an atom, molecule or atom in a molecule. This potential gives rise to a tube of magnetic flux carried around by the many-electron system. In time-dependent situations, the evolution of the electronic density distribution can be followed with simple, site-dependent cellular automaton (CA) rules. The CA consists of a lattice of sites, each with a finite set of possible values, here representing finite localized elements of electronic charge and current density (since the charge density rno longer suffices to fully characterize a time-dependent system, it needs to be supplemented with information about the current density j).Our numerical results are presented elsewhere and further developmentis in progress.

scholarly journals A targeted and tuneable DNA damage tool using CRISPR/Cas9

2021 ◽  
Author(s):  
Ioannis Emmanouilidis ◽  
Natalia Fili ◽  
Alexander W. Cook ◽  
Yukti Hari-Gupta ◽  
Ália dos Santos ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mammalian Cells ◽  
Genome Stability ◽  
Molecular Mechanisms ◽  
Low Cost ◽  
Strand Breaks ◽  
Guide Rnas ◽  
Area Of Interest ◽  
Culture Models ◽  
Repair Pathways

ABSTRACTMammalian cells are constantly subjected to a variety of DNA damaging events that lead to the activation of DNA repair pathways. Understanding the molecular mechanisms of the DNA damage response allows the development of therapeutics which target elements of these pathways.Double-Strand Breaks (DSB) are particularly deleterious to cell viability and genome stability. Typically, DSB repair is studied using DNA damaging agents such as ionising irradiation or genotoxic drugs. These induce random lesions at non-predictive genome sites, where damage dosage is difficult to control. Such interventions are unsuitable for studying how different DNA damage recognition and repair pathways are invoked at specific DSB sites in relation to the local chromatin state.The RNA-guided Cas9 (CRISPR associated protein 9) endonuclease enzyme, is a powerful tool to mediate targeted genome alterations. Cas9-based genomic intervention is attained through DSB formation in the genomic area of interest. Here, we have harnessed the power to induce DSBs at defined quantities and locations across the human genome, using custom-designed promiscuous guide RNAs, based on in silico predictions. This was achieved using electroporation of recombinant Cas9-guide complex which provides a generic, low-cost and rapid methodology for inducing controlled DNA damage in cell culture models.

scholarly journals ROS-Mediated Signalling in Bacteria: Zinc-Containing Cys-X-X-Cys Redox Centres and Iron-Based Oxidative Stress

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Darío Ortiz de Orué Lucana ◽  
Ina Wedderhoff ◽  
Matthew R. Groves
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Posttranslational Modifications ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Disulfide Bridge ◽  
Transcriptional Level ◽  
Protein Activity ◽  
Antioxidative Stress ◽  
Detection Mechanisms

Bacteria are permanently in contact with reactive oxygen species (ROS), both over the course of their life cycle as well that present in their environment. These species cause damage to proteins, lipids, and nucleotides, negatively impacting the organism. To detect these ROS molecules and to stimulate the expression of proteins involved in antioxidative stress response, bacteria use a number of different protein-based regulatory and sensory systems. ROS-based stress detection mechanisms induce posttranslational modifications, resulting in overall conformational and structural changes within sensory proteins. The subsequent structural rearrangements result in changes of protein activity, which lead to regulated and appropriate response on the transcriptional level. Many bacterial enzymes and regulatory proteins possess a conserved signature, the zinc-containing redox centre Cys-X-X-Cys in which a disulfide bridge is formed upon oxidative stress. Other metal-dependent oxidative modifications of amino acid side-chains (dityrosines, 2-oxo-histidines, or carbonylation) also modulate the activity of redox-sensitive proteins. Using molecular biology, biochemistry, biophysical, and structure biology tools, molecular mechanisms involved in sensing and response to oxidative stress have been elucidated in detail. In this review, we analyze some examples of bacterial redox-sensing proteins involved in antioxidative stress response and focus further on the currently known molecular mechanism of function.

scholarly journals A Targeted and Tuneable DNA Damage Tool Using CRISPR/Cas9

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 288
Author(s):  
Ioannis Emmanouilidis ◽  
Natalia Fili ◽  
Alexander W. Cook ◽  
Yukti Hari-Gupta ◽  
Ália dos Santos ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mammalian Cells ◽  
Genome Stability ◽  
Molecular Mechanisms ◽  
Low Cost ◽  
Strand Breaks ◽  
Guide Rnas ◽  
Area Of Interest ◽  
Culture Models ◽  
Repair Pathways

Mammalian cells are constantly subjected to a variety of DNA damaging events that lead to the activation of DNA repair pathways. Understanding the molecular mechanisms of the DNA damage response allows the development of therapeutics which target elements of these pathways. Double-strand breaks (DSB) are particularly deleterious to cell viability and genome stability. Typically, DSB repair is studied using DNA damaging agents such as ionising irradiation or genotoxic drugs. These induce random lesions at non-predictive genome sites, where damage dosage is difficult to control. Such interventions are unsuitable for studying how different DNA damage recognition and repair pathways are invoked at specific DSB sites in relation to the local chromatin state. The RNA-guided Cas9 (CRISPR-associated protein 9) endonuclease enzyme is a powerful tool to mediate targeted genome alterations. Cas9-based genomic intervention is attained through DSB formation in the genomic area of interest. Here, we have harnessed the power to induce DSBs at defined quantities and locations across the human genome, using custom-designed promiscuous guide RNAs, based on in silico predictions. This was achieved using electroporation of recombinant Cas9-guide complex, which provides a generic, low-cost and rapid methodology for inducing controlled DNA damage in cell culture models.

scholarly journals Calculate the one – expectation to electronic charge of atomic system contiun two electron

2010 ◽  
Vol 7 (1) ◽  
pp. 6-9
Author(s):  
Baghdad Science Journal
Keyword(s):  
Density Function ◽  
Atomic System ◽  
Electronic Charge ◽  
Electronic Density ◽  
Expectation Value ◽  
Hartree Fock ◽  
The One ◽  
He Atom

The aim of this work is to calculate the one- electron expectation value of the electronic charge of atomic system Z=2,3….7 and we compare with He atom . the electronic density function D(r1) of He atom and like ions are evaluated . using Hartree –Fock wave.

Spectral Bandwidths of Colour Detection Mechanisms

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 44-44
Author(s):  
M D'Zmura ◽  
K Knoblauch
Keyword(s):  
Optimal Strategy ◽  
Spectral Properties ◽  
Spectral Bandwidth ◽  
Detection Mechanism ◽  
Noise Masking ◽  
New Methods ◽  
Masking Noise ◽  
Detection Mechanisms ◽  
Colour Signals

We measured the spectral properties of human colour detection mechanisms with a noise masking paradigm, using two new methods to overcome a potential artefact of previous procedures. Estimation of the spectral bandwidth mediating detection of binary colour signals (eg orange) would be misleadingly narrow if the observer changes strategy as a function of the colour of the masking noise (eg detecting the red component of an orange signal in yellow noise and vice versa). We induce observers to use a single detection mechanism throughout an experiment by adding either biaxial noise or sectored noise to the signal. With biaxial noise, one can eliminate detectability of an orange signal by a red-sensitive mechanism, for instance, by adding a steady source of noise along a red axis. We then measure the remaining (yellow) sensitivity by adding noise along a second, variable axis. Sectored noise consists of noise samples from sectors of variable width in the colour plane, centred around the signal axis. Detection with the use of off-axis mechanisms is a less optimal strategy with such noise. A decline in the potency of such noise with increasing sector width would suggest that the spectral bandwidth is narrow and nonlinear rather than broad and more nearly linear.

scholarly journals Cyclic Nanostructures of Tungsten OxideWO3n  (n=2–6)asNOxGas Sensor: A Theoretical Study

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Izadyar ◽  
Azam Jamsaz
Keyword(s):  
Charge Transfer ◽  
Tungsten Oxide ◽  
Gas Sensors ◽  
Theoretical Study ◽  
Electronic Charge ◽  
Chemical Hardness ◽  
Transfer Enhancement ◽  
Sensitive Layer ◽  
Electronic Density ◽  
Electronic Charge Transfer

Today’s WO3-based gas sensors have received a lot of attention, because of important role as a sensitive layer for detection of the small quantities of  NOx. In this research, a theoretical study has been done on the sensing properties of different cyclic nanoclusters ofWO3n  (n=2–6)forNOx  (x=1,2)gases. Based on the calculated adsorption energies by B3LYP and X3LYP functionals, from the different orientations of  NOxmolecule on the tungsten oxide clusters, O–N⋯W was preferred. Different sizes of the mentioned clusters have been analyzed and W2O6cluster was chosen as the best candidate forNOxdetection from the energy viewpoint. Using the concepts of the chemical hardness and electronic charge transfer, some correlations between the energy of adsorption and interaction energy have been established. These analyses confirmed that the adsorption energy will be boosted with charge transfer enhancement. However, the chemical hardness relationship is reversed. Finally, obtained results from the natural bond orbital and electronic density of states analysis confirmed the electronic charge transfer from the adsorbates to WO3clusters and Fermi level shifting after adsorption, respectively. The last parameter confirms that the cyclic clusters of tungsten oxide can be used asNOxgas sensors.

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