scholarly journals Ολοκληρωμένη συστοιχία αισθητήρων βασισμένη σε πολυμερή για την αναγνώριση πτητικών αερίων

2012 ◽  
Author(s):  
Πέτρος Οικονόμου
Keyword(s):  
Binary Mixtures ◽  
Sensor Array ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Principal Component ◽  
Polymeric Materials ◽  
Integrated Sensor ◽  
Electromagnetic Model ◽  
The Individual ◽  
Electronic Elements

In this research the sensor type of planar InterDigitated Capacitors (IDCs), also known as chemcapacitors, is demonstrated and its application in the detection of Volatile Organic Compounds (VOCs) and humidity is explored. The IDC layout configuration is studied by using a dedicated electromagnetic model and the behavior of different planar IDE structures/geometries coated with different polymeric materials of different dielectric permittivity values (εp) is determined. This study leads to the optimum design geometry of the planar IDCs that will be used for the detection of analytes. In order to identify the more suitable sensing materials for the targeted application, a methodology based on swelling measurements of the polymeric material upon exposure to analytes of interest was developed and applied in the prediction of the response of a chemcapacitor upon exposure to different VOCs. The integrated sensor array is characterized by the responses of each sensor to exposure to several pure analytes, binary mixtures of analytes and complex environments. Several parameters were examined such as sensitivity, selectivity, limit of detection, aging. Also the total response of the sensor array is analyzed by conjunction of the individual responses of each sensor and the use of suitable Principal Component Analysis, PCA, models that have been developed. Fabrication of a hybrid low-power gas sensing module is presented. This module is realized with integration on the same device of the sensor array with the appropriate electronic elements. The latter provide the power, control and read-out electronics of the output signal. The proposed hybrid micro-device is characterized in terms of the response of each sensor of the sensor array upon exposure to different pure analytes and their binary mixtures. Evaluation of the results obtained by the characterization of the hybrid gas sensing module demonstrate the ability of use such a device in analytical methods under conditions of constant or alterable concentration of VOCs/humidity or their mixtures in applications either at constant temperature or at temperature changing over time simulating that way real time applications.

scholarly journals Selective and self-validating breath-level detection of hydrogen sulfide in humid air by gold nanoparticle-functionalized nanotube arrays

Nano Research ◽  
2021 ◽  
Author(s):  
Luis Antonio Panes-Ruiz ◽  
Leif Riemenschneider ◽  
Mohamad Moner Al Chawa ◽  
Markus Löffler ◽  
Bernd Rellinghaus ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Room Temperature ◽  
Sensor Array ◽  
High Selectivity ◽  
Electrochemical Sensors ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Electrical Characteristics ◽  
Sensor Fabrication ◽  
Walled Carbon Nanotubes

AbstractWe demonstrate the selective detection of hydrogen sulfide at breath concentration levels under humid airflow, using a self-validating 64-channel sensor array based on semiconducting single-walled carbon nanotubes (sc-SWCNTs). The reproducible sensor fabrication process is based on a multiplexed and controlled dielectrophoretic deposition of sc-SWCNTs. The sensing area is functionalized with gold nanoparticles to address the detection at room temperature by exploiting the affinity between gold and sulfur atoms of the gas. Sensing devices functionalized with an optimized distribution of nanoparticles show a sensitivity of 0.122%/part per billion (ppb) and a calculated limit of detection (LOD) of 3 ppb. Beyond the self-validation, our sensors show increased stability and higher response levels compared to some commercially available electrochemical sensors. The cross-sensitivity to breath gases NH3 and NO is addressed demonstrating the high selectivity to H2S. Finally, mathematical models of sensors’ electrical characteristics and sensing responses are developed to enhance the differentiation capabilities of the platform to be used in breath analysis applications.

PENELITIAN DAN PENGEMBANGAN SENSOR AROMATIK SEBAGAI ALAT DETEKSI ALKOHOL PADA PARFUM DAN WEWANGIAN UNTUK AUTENTIKASI PRODUK PARFUM HALAL

2017 ◽  
Vol 18 (2) ◽  
pp. 302-322
Author(s):  
Fajar Hardoyono
Keyword(s):  
Sensor Array ◽  
Principal Component ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Response Patterns ◽  
Data Recording ◽  
Analysis Method ◽  
Sample Group ◽  
Array Pattern ◽  
Group Data

Abstract: The development of aromatic sensor array instrument for the detection of alcohol in perfume. The research was conducted by developing the sensor array using 8 sensors made of metal oxide semiconductor. The sensor types used in this study consisted of TGS 813, TGS 822, TGS 2600, TGS 826, TGS 2611, TGS 2620, TGS 2612 and TGS 2602. Response patterns of 8 sensors formed a sensor array pattern used to detect the aroma of 2 groups of samples perfume made from the essential oil of ginger. The first sample group is pure ginger atsiri oil without mixed alcohol. The second sample group was made from the ginger atsiri oil mixed with alcohol with a level of 0.02 M. The results of the data recording show that the developed instrument is able to dissect the first sample group with the second sample group. Data analysis using principal component analysis method (PCA shows that the instrument is able to distinguish the contaminated alcohol perfume group 0.2 M with the alcohol-free perfume group with 100% accuracy. Keywords: Sensor Aroma, Perfume.

scholarly journals Using the Variable Geometry in a Planar Inductor for an Optimised Performance

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 721
Author(s):  
Maha Aldoumani ◽  
Baris Yuce ◽  
Dibin Zhu
Keyword(s):  
Smart Cities ◽  
Theoretical Concept ◽  
Displacement Sensor ◽  
Sensor Systems ◽  
Performance Modelling ◽  
Integrated Sensor ◽  
Complex Information ◽  
Electromagnetic Sensor ◽  
The Individual ◽  
Uncertainty Models

In this paper, the performance, modelling and application of a planar electromagnetic sensor are discussed. Due to the small size profiles and their non-contact nature, planar sensors are widely used due to their simple and basic design. The paper discusses the experimentation and the finite element modelling (FEM) performed for developing the design of planar coils. In addition, the paper investigates the performance of various topologies of planar sensors when they are used in inductive sensing. This technique has been applied to develop a new displacement sensor. The ANSYS Maxwell FEM package has been used to analyse the models while varying the topologies of the coils. For this purpose, different models in FEM were constructed and then tested with topologies such as circular, square and hexagon coil configurations. The described methodology is considered an effective way for the development of sensors based on planar coils with better performance. Moreover, it also confirms a good correlation between the experimental data and the FEM models. Once the best topology is chosen based on performance, an optimisation exercise was then carried out using uncertainty models. That is, the influence of variables such as number of turns and the spacing between the coils on the output inductance has been investigated. This means that the combined effects of these two variables on the output inductance was studied to obtain the optimum values for the number of turns and the spacing between the coils that provided the highest level of inductance from the coils. Integrated sensor systems are a pre-requisite for developing the concept of smart cities in practice due to the fact that the individual sensors can hardly meet the demands of smart cities for complex information. This paper provides an overview of the theoretical concept of smart cities and the integrated sensor systems.

scholarly journals Bioactive Phenolic Metabolites from Adriatic Brown Algae Dictyota dichotoma and Padina pavonica (Dictyotaceae)

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1187
Author(s):  
Ivana Generalić Mekinić ◽  
Vida Šimat ◽  
Viktorija Botić ◽  
Anita Crnjac ◽  
Marina Smoljo ◽  
...  
Keyword(s):  
Total Phenolics ◽  
Antioxidant Activities ◽  
Principal Component ◽  
Ultrasound Assisted Extraction ◽  
Antioxidant Power ◽  
Dictyota Dichotoma ◽  
Assisted Extraction ◽  
Sample Data ◽  
Ferric Reducing Antioxidant Power ◽  
The Individual

In this study, the influences of temperature (20, 40 and 60 °C) and extraction solvents (water, ethanol) on the ultrasound-assisted extraction of phenolics from the Adriatic macroalgae Dictyota dichotoma and Padina pavonica were studied. The extracts were analysed for major phenolic sub-groups (total phenolics, flavonoids and tannins) using spectrometric methods, while the individual phenolics were detected by HPLC. The antioxidant activities were evaluated using three methods: Ferric Reducing/Antioxidant Power (FRAP), scavenging of the stabile 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and Oxygen Radical Antioxidant Capacity (ORAC). The aim of the study was also to find the connection between the chemical composition of the extracts and their biological activity. Therefore, principal component analysis (PCA), which permits simple representation of different sample data and better visualisation of their correlations, was used. Higher extraction yields of the total phenolics, flavonoids and tannins were obtained using an alcoholic solvent, while a general conclusion about the applied temperature was not established. These extracts also showed good antioxidant activity, especially D. dichotoma extracts, with high reducing capacity (690–792 mM TE) and ORAC values (38.7–40.8 mM TE in 400-fold diluted extracts). The PCA pointed out the significant influence of flavonoids and tannins on the investigated properties. The results of this investigation could be interesting for future studies dealing with the application of these two algae in foods, cosmetics and pharmaceuticals.

Genomic immunotherapy (IO) biomarkers detected on comprehensive genomic profiling (CGP) of tissue and circulating tumor DNA (ctDNA).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2541-2541
Author(s):  
Takayuki Yoshino ◽  
Hanna Tukachinsky ◽  
Jessica Kim Lee ◽  
Ethan Sokol ◽  
Dean C. Pavlick ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Predictive Biomarkers ◽  
Principal Component ◽  
Pathogenic Mutation ◽  
Circulating Tumor Dna ◽  
Driver Mutations ◽  
Cancer Type ◽  
Liquid Biopsies ◽  
Mutational Burden ◽  
Relative Prevalence

2541 Background: The dramatic impact of IO on treatment outcomes has heightened interest in predictive biomarkers, including genomic markers such as tumor mutational burden (TMB) and microsatellite instability (MSI). The recent FDA approval of pembrolizumab for previously treated advanced solid tumors with elevated TMB (≥10 mut/Mb on FoundationOne CDx, F1CDx) now requires a better understanding of the prevalence of this and other IO biomarkers detected on CGP, including differences between TMB detected in tissue and mutational burden detected in blood (bTMB). Methods: Tissue and plasma biopsies were profiled with two CGP panels of 324 genes with 0.8 Mb genome coverage (F1CDx and FoundationOne LiquidCDx). Mutational burden was calculated by counting somatic variants (single nucleotide and indels, including synonymous variants, excluding germline and driver mutations) with variant allele frequency (VAF) ≥5% in tissue (TMB) or ≥0.5% in ctDNA (bTMB). MSI score was assessed using 95 repetitive loci and principal component analysis (tissue) or >1,800 repetitive loci (plasma). ctDNA levels were estimated using composite tumor fraction (cTF), a metric based on aneuploidy and VAF. Results: Pan-cancer, TMB ≥10 was detected in 19% of tissue cases (29,238/156,294) and was common in melanoma (53%), small cell (41%), NSCLC (40%), bladder (39%), and endometrial (24%). bTMB ≥10 was detected in 13% of liquid biopsies (806/6,295); prevalence by cancer type was correlated with prevalence of elevated TMB (r = 0.81). Samples with bTMB ≥10 had an elevated cTF (median 13%, IQR 5 - 31%) as compared to samples with bTMB <10 (median 1.8%, IQR 0.6 - 7%, p < 0.001). Among 353 cases with both tissue and liquid CGP results (median 11 months apart), the relative prevalence of TMB ≥10 (12%) and bTMB ≥10 (13%) were similar, with concordant detection in 303 cases (86%). MSI-high (MSI-H) was seen in 2.2% of tissue CGP (3,461/156,294), most often in endometrial (19%), stomach (6.0%), and colorectal (5.3%) cancers, while MSI-H was detected in 0.68% of ctDNA specimens (43/6,295), which were also those with elevated cTF (median 11%, IQR 7 - 23%). Of 3,504 cases with MSI-H signature on tissue or liquid CGP, 1,619 (46%) had a pathogenic mutation detected in MLH1/MSH2/MSH6/PMS2 (15% predicted germline). CD274 amplification was detected in 1,207 cases (0.77%) of tissue CGP and 11 cases (0.17%) in ctDNA. Conclusions: Elevated bTMB is overall less prevalent than elevated tissue TMB, though these biomarkers are detected in similar cancer types. Detection of bTMB ≥10 and MSI-H in liquid biopsy was associated with elevated ctDNA levels, suggesting a limit of detection, and potentially indicating a more aggressive biology in samples positive for these biomarkers. Further investigation is needed to understand the utility of bTMB for identifying high TMB tumors that may benefit from IO.

Combinatorial selectivity with an array of phthalocyanines functionalized TiO2/ZnO heterojunction thin film sensors

2021 ◽  
Author(s):  
Yuvaraj Sivalingam ◽  
Gabriele Magna ◽  
Ramji Kalidoss ◽  
Sarathbavan Murugan ◽  
David Chidambaram ◽  
...  
Keyword(s):  
Sensor Array ◽  
Principal Component ◽  
Optically Active ◽  
Inorganic Materials ◽  
Chemical Sensitivity ◽  
Electronic Noses ◽  
Thin Film Sensors ◽  
Sensor Resistance ◽  
Virtual Array ◽  
Hydrogen Bond Basicity

Abstract The development of electronic noses requires the control of the selectivity pattern of each sensor of the array. Organic chemistry offers a manifold of possibilities to this regard but in many cases the chemical sensitivity is not matched with the response of electronic sensor. The combination of organic and inorganic materials is an approach to transfer the chemical sensitivities of the sensor to the measurable electronic signals. In this paper, this approach is demonstrated with a hybrid material made of phthalocyanines and a bilayer structure of ZnO and TiO2. Results show that the whole spectrum of sensitivity of phthalocyanines results in changes of the resistance of the sensor, and even the adsorption of compounds, such as hexane, which cannot change the resistance of pure phthalocyanine layers, elicits changes of the sensor resistance. Furthermore, since phthalocyanines are optically active, the sensitivity in dark and visible light are different. Thus, operating the sensor in dark and light two different signals per sensors can be extracted. As a consequence, an array of 3 sensors made of different phthalocyanines results in a virtual array of six sensors. The sensor array shows a remarkable selectivity respect to a set of test compounds. Principal component analysis scores plot illustrates that hydrogen bond basicity and dispersion interaction are the dominant mechanisms of interaction.

scholarly journals Qualitative Analysis of Traditional Italian Dishes: FTIR Approach

2018 ◽  
Vol 10 (11) ◽  
pp. 4112 ◽  
Author(s):  
Alessandra Durazzo ◽  
Johannes Kiefer ◽  
Massimo Lucarini ◽  
Emanuela Camilli ◽  
Stefania Marconi ◽  
...  
Keyword(s):  
Qualitative Analysis ◽  
Ftir Spectroscopy ◽  
Functional Groups ◽  
Food Systems ◽  
Principal Component ◽  
Integrated Approach ◽  
Spectroscopic Characterization ◽  
Cooking Methods ◽  
Food Research ◽  
The Individual

Italian cuisine and its traditional recipes experience an ever-increasing popularity around the world. The “Integrated Approach” is the key to modern food research and the innovative challenge for analyzing and modeling agro-food systems in their totality. The present study aims at applying and evaluating Fourier Transformed Infrared (FTIR) spectroscopy for the analysis of complex food matrices and food preparations. Nine traditional Italian recipes, including First courses, One-dish meals, Side courses, and Desserts, were selected and experimentally prepared. Prior to their analysis via FTIR spectroscopy, the samples were homogenized and lyophilized. The IR spectroscopic characterization and the assignment of the main bands was carried out. Numerous peaks, which correspond to functional groups and modes of vibration of the individual components, were highlighted. The spectra are affected by both the preparation procedures, the cooking methods, and the cooking time. The qualitative analysis of the major functional groups can serve as a basis for a discrimination of the products and the investigation of fraud. For this purpose, the FTIR spectra were evaluated using Principal Component Analysis (PCA). Our results show how the utilization of vibrational spectroscopy combined with a well-established chemometric data analysis method represents a potentially powerful tool in research linked to the food sector and beyond. This study is a first step towards the development of new indicators of food quality.

scholarly journals Powder properties of binary mixtures of chloroquine phosphate with lactose and dicalcium phosphate

2010 ◽  
Vol 46 (3) ◽  
pp. 531-537
Author(s):  
Michael Ayodele Odeniyi ◽  
Collins Chidi Onyenaka ◽  
Oludele Adelanwa Itiola
Keyword(s):  
Binary Mixtures ◽  
Internal Flow ◽  
Optical Microscope ◽  
Volume Reduction ◽  
Dicalcium Phosphate ◽  
Flow Properties ◽  
Maximum Volume ◽  
Cohesive Properties ◽  
Particle Size And Shape ◽  
The Individual

A study was conducted on the packing and cohesive properties of chloroquine phosphate in binary mixtures with lactose and dicalcium phosphate powders. The maximum volume reduction due to packing as expressed by the Kawakita constant, a, and the angle of internal flow, θ, were the assessment parameters. The individual powders were characterized for their particle size and shape using an optical microscope. Binary mixtures of various proportions of chloroquine phosphate with lactose and dicalcium phosphate powders were prepared. The bulk and tapped densities, angles of repose and internal flow, as well as compressibility index of the materials were determined using appropriate parameters. The calculated and determined values of maximum volume reduction for the binary mixtures were found to differ significantly (P< 0.05), with the Kawakita plot being more reliable in determining the packing properties. Diluent type was found to influence the flow properties of the mixtures, with dicalcium phosphate giving predictable results while mixtures containing lactose were anomalous with respect to flow. The characterization of the packing and cohesive properties of the binary mixtures of chloroquine with lactose and dicalcium phosphate would be useful in the production of powders, tablets, capsules and other drug delivery systems containing these powders with desirable and predictable flow properties.

scholarly journals Comparison and Identification for Rhizomes and Leaves of Paris yunnanensis Based on Fourier Transform Mid-Infrared Spectroscopy Combined with Chemometrics

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3343 ◽  
Author(s):  
Yi-Fei Pei ◽  
Qing-Zhi Zhang ◽  
Zhi-Tian Zuo ◽  
Yuan-Zhong Wang
Keyword(s):  
Fourier Transform ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Chemical Information ◽  
Accurate Identification ◽  
Mid Infrared ◽  
Model Classification ◽  
Paris Polyphylla ◽  
Mir Spectra ◽  
The Individual

Paris polyphylla, as a traditional herb with long history, has been widely used to treat diseases in multiple nationalities of China. Nevertheless, the quality of P. yunnanensis fluctuates among from different geographical origins, so that a fast and accurate classification method was necessary for establishment. In our study, the geographical origin identification of 462 P. yunnanensis rhizome and leaf samples from Kunming, Yuxi, Chuxiong, Dali, Lijiang, and Honghe were analyzed by Fourier transform mid infrared (FT-MIR) spectra, combined with partial least squares discriminant analysis (PLS-DA), random forest (RF), and hierarchical cluster analysis (HCA) methods. The obvious cluster tendency of rhizomes and leaves FT-MIR spectra was displayed by principal component analysis (PCA). The distribution of the variable importance for the projection (VIP) was more uniform than the important variables obtained by RF, while PLS-DA models obtained higher classification abilities. Hence, a PLS-DA model was more suitably used to classify the different geographical origins of P. yunnanensis than the RF model. Additionally, the clustering results of different geographical origins obtained by HCA dendrograms also proved the chemical information difference between rhizomes and leaves. The identification performances of PLS-DA and the RF models of leaves FT-MIR matrixes were better than those of rhizomes datasets. In addition, the model classification abilities of combination datasets were higher than the individual matrixes of rhizomes and leaves spectra. Our study provides a reference to the rational utilization of resources, as well as a fast and accurate identification research for P. yunnanensis samples.

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